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Bag filters for aluminium dust extraction

Odsávání při broušení explozních prachů

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In our catalog we have included filter units that are by design directly made for use in aluminum dust extraction applications. This dust is created by grinding aluminum or other non-metallic materials. Our catalog includes 18 basic baghouse units for dust created by grinding aluminum or other explosive material.  This dust forms an explosive atmosphere with air. The bag filter units are graded according to the required volumetric airflow.

Parameters of dust resulted from aluminium grinding

When grinding aluminum materials, dust particles are released into the work area, which can form an explosive atmosphere with the air. This dust is very important to extract efficiently, as even the dust sediments in the working environment are undesirable. Explosive dusts are specific by their values of Kst (bar.m/s) and Pmax (bar). The baghouse units included in the catalog are designed for the fine aluminum powder produced by grinding.

Dedusting when grinding aluminium

Extraction at the source

Extraction at the source of dusting is the most effective way of capture.The dust particles are sucked out using stationary hoods or suction tables. Exhaust hoods of abrasive aluminum dusts are best used at worktables where smaller pieces are abraded. The suction hood provides dust extraction so that the worker does not come into contact with the abrasive dust aspirating away from the dust source. Exhausting desks are advantageous by allowing extraction to the suction worktable itself and by the suction hood away from the worker.  For suction hoods, count with extraction flow rate up to 1500 – 2000 m3/h for 1 meter of hood lenght. For suction worktables count with extraction flow rate of at least 2000 – 2500 m3/h for 1 meter of the table lenght.

Dedusting of automated aluminium grinders

In terms of extraction and determination of extraction flow rate, it is always necessary to meet the requirements of the manufacturer of the grinding machine. Dedusting here with its proper function ensures suction of explosive dust that would otherwise settle in the interior of the machine and could result in an explosive atmosphere. The formation of an explosive atmosphere in the machine needs to be avoided. One of the options is to regularly clean the machine so that the sedimented dust does not create deposits in the corners and non-extracted areas of the machine. The grinding machines are almost always already equipped with suction hoods and covers, but it is very important to keep the manufacturer’s prescribed flow velocity in the connecting ducts, which is usually set at 30 meters per second.

Parameters of extracting explosive dust resulted from aluminium grinding

The design and implementation of extracting explosive dust must adhere to at least these basic rules. The suction line must be properly electrically connected between the components from the suction device to the baghouse unit. The whole system must be properly grounded. The baghouse must be equiped with proper explosion vents directed into a safe location. The filter housing must be pressure resistant, the bag medium must be antistatic. The exhaust duct must be fitted with a non-return backflap valve to prevent baghouse explosion spreading into the suction line, and the suction ducting flow rate must not fall below 20 meters per second.

Parameters of baghouse units for extracting Al dust

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience of individual extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter. The filter medium does not contain folds where the dust be sedimented and is very mechanically resistant to tearing or scraping. The amount of residual dust particles ranges from 0,25 mg/m3 to 1 mg/m3, which allows for cleaned air to be recirculated back into the plant for heating and save costs.  When returning the filtered air, it is necessary to place a residual dust sensor in the exhaust pipe so that the purity of the filtered air can be continuously monitored. If the set dust limit should be exceeded, the system must shut down immediately or switch the exhaust to the outdoor environment without delay. The filtering device must be positioned so that the explosion vents are directed into a safe space.

Recommended ducting solution for aluminium dust extraction

For aluminum dust extraction applications, we recommend to design the ducting with a combination of straight sections in spirally wound piping (a.k.a. SPIRO) with flanged joints and fittings (tapping, knees, flaps) in Group II welded flanged finish. We recommend this combination because of the extraction of the slightly abrasive dust, which usually abrades the places of  air direction change = branches and elbows. We do not recommend using riveted joints so that the inside of the pipeline remains smooth throughout its length. The part of the ducting between the baghouse unit and the backflap valve must be made of a pressure resistant pipe Group II or Group III.

Baghouse units for aluminium dust extraction in the GIDLY catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Manual aluminium grinding EX“. In the next step, select the required volumetric airflow of the bag filter unit. The result will be a set of items – baghouse unit+ explosion dust design parameters + fan +  silencer box, all of which form a dedusting system. You can then insert the items into the costing.

 

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Bag filters for coal dust extraction

Odprášení dopravních cest uhlí

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In our catalog we have included filter units that are by design directly made for use in explosive dust extraction applications. This specific dust is emerging when working with coal. Our catalog includes 18 basic baghouse units for coal dust that forms an explosive atmosphere with air. The bag filter units are graded according to the required volumetric airflow.

Parameters of coal dust

When handling coal, dust particles are released into the air and these can easily form an explosive atmosphere when mixed with air. This dust is very important to extract efficiently, as even the dust sediments in the working environment are undesirable. Explosive dusts are specific by their values of Kst (bar.m/s) and Pmax (bar). The baghouse units included in the catalog are designed for the fine coal dust normally found in enviroments such as power plants or coking plants.

Coal dust extraction

Dedusting of coal unloading pits

In the operation of the coal pits or coal dumps, wagons are unloaded into the underground reservoirs from where the coal is transported to further processing. Upon unloading, coal from the wagon drains off within seconds and dust leaks into the operator area. An efficient dedusting system ensures dust extraction before the dust rises to the operator’s work area. We recommend to place suction fittings in the space between the grates and the wagon operator ramps.  We recommend to extract circa 40 000 m3/h per one unloaded coal wagon.

Coaling space dust extraction

Coaling is the path from the coal dump to the bunkers in the boiler room. Part of the coaling path is an hourglass station, where conveyors of conveyor belts can change the way of conveyed coal and other belt conveyors. Part of the coaling path is an drift station, where different conveyor belts can change the way of conveyed coal to other belt conveyors. At the end of the conveying route, coal is filled into one of the bunkers. Dust extraction is always divided into individual dedusted areas that can dedust one central bunker. The Overp (drift) stations extract dust by a separate central extraction technology and the top over area with bunker filling station also by a separate dedusting system. The dust from the filter device is always returned to the conveyor belt conveyor so as to avoid any losses of coal.  The extraction flow rate for drifts is always set down to at least Q= 2500 – 3500 m3/h and Q= 6000 – 8000 m3/h for bunker dedusting.

Parameters for extraction of explosive coal dust

The design and implementation of extracting explosive dust must adhere to at least these basic rules. The suction line must be properly electrically connected between the components from the suction device to the baghouse unit. The whole system must be properly grounded. The baghouse must be equiped with proper explosion vents directed into a safe location. The filter housing must be pressure resistant, the bag medium must be antistatic. The exhaust duct must be fitted with a non-return backflap valve to prevent baghouse explosion spreading into the suction line, and the suction ducting flow rate must not fall below 20 meters per second.

Parameters of baghouse units for extracting coal dust

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience of individual extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter. The filter medium does not contain folds where the dust be sedimented and is very mechanically resistant to tearing or scraping. The amount of residual dust particles ranges from 0,25 mg/m3 to 1 mg/m3, which allows for cleaned air to be recirculated back into the plant for heating and save costs.  When returning the filtered air, it is necessary to place a residual dust sensor in the exhaust pipe so that the purity of the filtered air can be continuously monitored. If the set dust limit should be exceeded, the system must shut down immediately or switch the exhaust to the outdoor environment without delay. The filtering device must be positioned so that the explosion vents are directed into a safe space.

Recommended ducting solution for coal dust extraction

For aluminum dust extraction applications, we recommend to design the ducting with a combination of straight sections in spirally wound piping (a.k.a. SPIRO) with flanged joints and fittings (tapping, knees, flaps) in Group II welded flanged finish. We recommend this combination because of the extraction of the slightly abrasive dust, which usually abrades the places of  air direction change = branches and knees. We do not recommend using riveted joints so that the inside of the pipeline remains smooth throughout its length. The part of the ducting, ie between the baghouse unit and the backflap valve must be made of a pressure resistant pipe Group II or Group III.

Baghouse units for coal dust extraction in the GIDLY catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Coal dust extraction – EX“. In the next step, select the required volumetric airflow of the bag filter unit. The result will be a set of items – baghouse unit+ explosion dust design parameters + fan +  silencer box, all of which form a dedusting system. You can then insert the items into the costing.

 

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Bag filters for ceramic dust extraction

Odsávání živcového prachu

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The GIDLY catalog includes baghouse filter units designed for use in aplications of ceramic dust extraction. Our catalog includes 18 basic baghouse units for ceramic dust graded according to the required volumetric airflow.

Parameters of ceramic dust extraction

By the term ceramic and stony dust, we mean the dust arising in the production lines of stone processing in quarries and products in plants for production of building materials such as tiles, bricks, roofing etc. Ceramic dust is highly abrasive, very fine, dry and does not stick.

Extraction of ceramic dust

Dedusting in quarries

Dedusting in quarries is often a combination of wet sprinkling and dry extraction. By means of dry baghouse systems, the main extracted work places are crushers, screeners, belt conveyors and fill nozzles. The crushers are usually equipped with a suction fitting for the suction duct and thus the required amount of exhausted air is defined by its manufactorer. For sorting machines it is necessary to ensure a sufficiently tight hood with fittings for connection of the exhaust pipe. Individual belt conveyor overhangs must be properly covered and dedusted at the point of the hopper from the belt and impact on the downstream conveyor belt. The usual extraction flow rate for conveyor belt drifts is circa 2500–3500 m3/h. With filling nozzles the required extraction flow rate is usually set by its manufacturer,normally about 1500 m3/h.

Dedusting in production lines of ceramic products

Central dust extraction systems are frequently used both at complete production lines and at single-purpose machines. An example of dust extraction from a single-purpose machine is the dedusting of precision brick grinders. When grinding, it is necessary to have a high extraction flow rate to ensure that the abrasive is extracted from the grinder into the baghouse. Extremely fine dust particles as well as fragments of bricks are normally getting into the ducting. Dust is very abrasive and causes the pipeline to be scraped through in places of change in the direction of air – such as  elbows and branches. Unfortunately, the scraping and stripping cannot be eliminated because of the air speed needed to drift larger fragments away.  The air speed in the ducting pipeline should be at least 22-24 m / s. With this specific technology, it is needed to have a extraction flow rate of at least 24 000 m3/h for one grinder. The required extraction flow rates are usually determined by the manufacturer of the grinding machines.

Recommended ducting solution

We recommend using Group III Ducting for ceramic dust extraction – a thick-walled, welded ducting. Pipeline components such as elbows, flaps, and branches are subject to abrasion from the dust particles and material fragments. Despite the thick walls of these components, it can not be ruled out that after a certain period of time they will be damaged by abrasion.

Baghouse units for ceramic dust extraction in the GIDLY catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Ceramic dust“. In the next step, select the required volumetric airflow of the bag filter unit. The result will be a set of items – baghouse unit+ explosion dust design parameters + fan +  silencer box, all of which form a dedusting system. You can then insert the items into the costing.

 

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Bag filters for lime and cement dust extraction

Odprášení cementového a vápenného prachu

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The GIDLY catalog includes baghouse filter units designed for use in aplications of lime and cement dust extraction.Our catalog includes 18 basic baghouse units for lime and cement dust graded according to the required volumetric airflow.

Parameters of lime and cement dust

The lime and cement dusts are specific by their hygroscopicity. The dust exhausted in the filtering device is very fine and tends to clog the pores in the bag medium and thus increase the pressure drop of the baghouse. The lime and cement dust is fine, abrasive and sticky.

Extraction of lime and cement dust

Central exhaust systems are often used to extract the production lines of lime and cement itself, as well as various mortar mixtures. In the production lines, individual sources of dust are extracted, such as mills, mixers, weighing stations and packing lines.  The baghouse is specific by a heat insulated housing with electricaly heated hopper.

Parameters of baghouse units

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience of individual extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter. The filter medium does not contain folds where the dust be sedimented and is very mechanically resistant to tearing or scraping. The amount of residual dust particles ranges from 0,25 mg/m3 to 1 mg/m3, which allows for cleaned air to be recirculated back into the plant for heating and save costs.  When returning the filtered air, it is necessary to place a residual dust sensor in the exhaust pipe so that the purity of the filtered air can be continuously monitored. If the set dust limit should be exceeded, the system must shut down immediately or switch the exhaust to the outdoor environment without delay. The filtering device must be positioned so that the explosion vents are directed into a safe space.

Recommended ducting solution

We recommend using Group III Ducting for ceramic dust extraction – a thick-walled, welded ducting. Pipeline components such as elbows, flaps, and branches are subject to abrasion from the dust particles. Despite the thick walls of these components, it can not be ruled out that after a certain period of time they will be damaged by abrasion.

Baghouse units for lime and cement dust extraction in the GIDLY catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Lime and cement dust“. In the next step, select the required volumetric airflow of the bag filter unit. The result will be a set of items – baghouse unit+ explosion dust design parameters + fan +  silencer box, all of which form a dedusting system. You can then insert the items into the costing.

 

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Bag filters for solid fuel boiler dedusting

Odprášení stacionárních tepelných zdrojů

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The Gidly catalog includes baghouse units that are directly designed for use in applications for solid fuel boiler dedusting. We are offering 13 basic baghouse units for extraction of dust from solid fuel boilers. The baghouse units are graded according to the required volumetric airflow.

Parameters of the dust

The temperature of the gases exhausted from the boiler is about 150 ° C to 180 ° C depending on the boiler operation status and type. Because it is a combustion source, the exhausted media are products of combustion. The proportion of water in the fuel increases the moisture content of the exhaust gas – there is therefore a risk of vapor condensation inside the ductwork and the baghouse. The extraction technology has to be thermally insulated and its hopper heated. The dust from the boiler is very fine, dark, dry and abrasive.

Boiler dedusting

The boiler manufacturer always provides the required ammount of vacuum and the amount of gas exhausted at a defined temperature. The function of the extraction system then directly affects the function of the boiler. The flue gas temperature is usually as low as 150 ° C to 180 ° C when sucked into the extraction system. A cyclone deduster must be installed in front of the baghouse to ensure the separation of coarse particles from exhaust gases – including sparks resulted from combustion. The cyclone deduster then reduces the risk of burning of the bags by the burning particles The bag medium of the must be made of materials with a temperature resistance of up to 200 ° C. The filtering device should be thermally insulated, the hopper of the baghouse is electrically heated by a resistive cable. We also recommend to heat the conveyors. The extraction flow rate of the dedusting system is controlled with the fan speed through an invertor. The fan is located on the clean baghouse side, ie behind. The vacuum sensor is placed in the pipeline behind the boiler. It is necessary to include a bypass of baghouse which is active during the boiler startup, before it approaches the target temperature. Bypass is important to prevent vapour condensation occuring when exposed to the low temperature of the flue gases.

Parameters of the baghouse

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience of individual extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter and a temperature resistance for up to 200° Celsius. The filter medium does not contain folds where the dust be sedimented and is very mechanically resistant to tearing or scraping. The amount of residual dust particles ranges from 5 mg/m3 do 10 mg/m3.

Recommended ducting solution

We recommend using Group III Ducting – a thick-walled, welded ducting. It is possible to use a pipe with a surface finish of chemical and thermal resistant insulating paints.

Baghouse units for boiler dust extraction in the GIDLY catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Solid fuel boiler dedusting“. Choose the required volumetric airflow value in the next step – marked in QV [m3/h] at t= 150°C . The result will be a set of components – baghouse + thermal insulation of the housing + thermal insulation and heating of the hopper + surface finish + stainless parts – fan – which all together result in the dedusting system. You can then insert the products in your costing.

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Bag filters for gas fired melting furnaces

Odsávání spalin tavící pece

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The Gidly catalog includes baghouse units that are directly designed for use in applications of gas fired melting furnaces dedusting. We are offering 14 basic baghouse units for extraction of dust from gas fired melting furnaces, graded according to the required volumetric airflow.

Dust parameters

The dust resulted from gas fired melting furnaces is dry and made up of light particles. The exhaust gas temperature ranges from 300 ° C to 400 ° C depending on the furnace operating condition. The resulted exhaust is a product of gas combustion. The gas fired furnace increases the humidity of the extracted dust, and therefore poses a risk of vapour condensation inside the ducting and baghouse. The extraction technology has to be thermally insulated and its hopper heated. The dust from the furnace is very fine, dark, dry and slightly abrasive.

Dedusting of the gas fired melting furnace

The modern dedusting systems of gas fired melting furnaces are separated into two groups: raw flue gas extraction without dilution by coolant ambient air for cooling and to dust extraction from the filling lid above the furnace opening.

Flue gas extraction during the melting

The furnace manufacturer always provides the required ammount of vacuum and the amount of gas exhausted at a defined temperature. The function of the extraction system then directly affects the function of the furnace. The flue gas temperature is usually  about 400 ° C to 300 ° C when sucked into the extraction system. In practice, there are two ways to cool the flue gas for the baghouse filter operating temperature. The first option is to control the additional amount of extracted ambient air into the ducting and thereby regulate the temperature. The disadvantage of this solution is the growth in size, in electricity consumption and in investment costs of the whole dedusting technology.

Another option is to cool the extracted hot furnace gas before the baghouse with a heat exchanger. The gathered heat can then be use either for heating the air burned in the furnace or for heating the plant in winter seasons. With heat exchange, the extracted flue gas shrinks in volume and the baghouse can be smaller. The minimum temperature of air in the extraction ducting should not drop lower than 100°C (min 80°C) to prevent condensation of vapour. Please note that the flue gas includes a portion of HF and HCL acids, excluding the use of zinc coated steel. The zinc coated steel would last only a few days while used with a gas fired furnace. We recommend to dose Ca(OH)2 into the extraction ducting to lower the content of HF and HCl acid and improve the regenerativnes of the bag medium. The amount of gas extracted is reported by the furnace manufacturer, indicated either by QN [Nm3/h] at a specific temperature, or by QV [m3/h], also with conjuction to a specific operation temperature.

Extracting smoke from the furnace lid

The extraction hood in the furnace is placed right over the charging inlet. The extraction is neccessary only when the lid is open and the charging occurs. The extraction hood provides smoke extraction so that it does not extend into the workspace. Since the burner is not open when the lid is open, it is not a combustion that is dedusted but just the in the plant. The extration duct is therefore not to be insulated because the air is not extracted at a higher humidity than the surrounding environment and there is no risk of condensation inside the ducting or baghouse. We still dont advise to galvanize the ducting. We recommend applying a temperature-resistant and chemically resistant coating. The amount of exhaust air is given by the manufacturer but can also be determined empirically at a minimum of 4000 to 5000 m3 / h per 1m length of the suction hood.

Parameters of the baghouse for gas fired melting furnaces dedusting

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience of individual extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter and a temperature resistance for up to 200° Celsius.  The filter medium does not contain folds where the dust be sedimented and is very mechanically resistant to tearing or scraping.  The amount of residual dust particles ranges from 1 mg/m3 do 5 mg/m3, but the filtered air cannot be recirculated back into the plant because the flue gas contains CO, CO2, HF, HCl, NOx and other toxic substances. However, the heat from the filtered air can be recovered using special tube heat exchangers with heat exchange surface regeneration technology.

Recommended ducting solution

We recommend using Group III Ducting – a thick-walled, welded ducting. When extracting hot flue gas, it is neccesary to use stainless ducting with heat insulation, and with furnace lid extraction to use ducting  with a temperature-resistant and chemically resistant coating.

Bag filters for gas fired melting furnaces in the GIDLY Catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Gas fired melting furnaces“. Choose the required volumetric airflow value in the next step – marked in QV [m3/h] at t= 150°C . The result will be a set of components – baghouse + thermal insulation of the housing + thermal insulation and heating of the hopper + surface finish + stainless parts – fan – which all together result in the dedusting system. You can then insert the products in your costing.

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Bag filters for induction melting furnaces

Odsávání spalin z indukčních pecí

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The Gidly catalog includes baghouse units that are directly designed for use in applications of gas fired melting furnaces dedusting. We are offering 18 basic baghouse units for extraction of dust from induction melting furnaces, graded according to the required volumetric airflow.

Dust parameters

The dust resulted from gas fired melting furnaces is dry and made up of light particles. The exhaust gas temperature ranges from 40 ° C to 60 ° C depending on the furnace operating condition. Since it is an electric induction furnace, it is not a true combustion because all the extracted air comes from the environment of the hall and is not a flue gas by definition. The induction furnace itself does not increase the humidity of the extracted air and therefore there is no risk of vapor condensation inside the ducting and the baghouse. The extraction technology does not need to be heat-insulated.  The dust from the furnace is very fine, dark, dry and slightly abrasive.

Dedusting of the induction furnace

Modern induction furnaces come with an integrated lid that can be used in one of two states. When melting, the lid is always closed. The extraction flow rate is then regulated to about 30% of its total capacity. The regulation is achieved with valves or flaps in the extraction ducting. The fan power is then regulated with respect to the vacuum in the ducting by the usage of an power invertor. When the lid is open and the furnace is charging the extraction flow rate is at maximum.  In this moment, the smoke generated is to be extracted by the open lid to prevent spreading into the plant. The regulation valve is open to 100% and the fan power is increased to a desired value.

In most cases, a pair of melting furnaces is dedusted by the bag filter. Regulation valves and the power inverter of the fan is controled automaticaly, linked to the operation state of the furnaces or the lids positions. The extraction flow rate amount required for open lid situation is determined by the furnace manufacturer. So far, we have not met with the induction furnace manufacturer determining a extraction flow rate when the lid is closed. This state is necessary to regulate when operating the technology. The regulation then allows for energy savings when operating the furnace by not extracting too much heat and thereby unncecesarily cool the product. Another benefit of regulating the extraction flow rate during the operation of the induction furnace is also the energy saving of the baghouse and longer life of the bags. The extraction flow rate required for sufficient extraction of the induction furnace is about 5000 to 40,000 m3 / h depending on the size of the induction furnace.

Parameters of the baghouse

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience of individual extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter and a temperature resistance for up to 200° Celsius.  The filter medium does not contain folds where the dust be sedimented and is very mechanically resistant to tearing or scraping. The amount of residual dust particles ranges from 1 mg/m3 do 5 mg/m3 but recirculation of the filtered air is not advised – the flue gas contains a significant odor. The heat from the filtered air can be recovered using any conventional heat exchanger.

Recommended ducting solution

We recommend using Group II welded, thick walled ducting when extracting dust from induction furnaces. The proven surface treatment of the ducts is galvanizing. The ducting itself is not subject to a significant abrasion, but we do not recommend to use Group I spirally wound ducts with respect to the thermal jumps between different operating states of the furnace.

Bag filters for induction melting furnaces in the GIDLY Catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Induction melting furnaces“. Choose the required volumetric airflow value in the next step. The result will be a set of components – baghouse – fan – which result in the dedusting system. You can then insert the products in your costing.

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Bag filters for cast iron dust

Odsávání při obrábění litiny

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The Gidly catalog includes baghouse units that are directly designed for use in applications of cast iron dust extraction. We are offering 17 basic baghouse units for extraction of dust from cast iron works, graded according to the required volumetric airflow.

Cast iron dust parameters

Among the cast iron dusts in this filter group belong dusts resulted from grinding, shot blasting or working of iron castings. The cast iron dust contains a very fine fraction which tends to clog the filter bag pores. The dust separated in the baghouse is sticky, hard to regenerate and requires a larger cloth area than the usual foundry dust. The cast iron dust is abrasive, heavy and contains particles from a coarse and a very fine fraction. When on the floor, the dust is very slippery due to the graphite content.

Cast iron dust extraction

Dedusting of portable blast machines

Blast machines are used for basic cleaning of the cast iron casting from foundry sand residues. In the blasting process, both the abrasive particles from the blasting machine and some of the sand and cast iron dust get into the extraction dedusting system. Separators are therefore included in the extraction ducting to ensure that only the dust particles of the cast iron are filtered by baghouse and the abrasive recirculates in the blaster only. The blasting machine is usually pre-equipped with dust separators from the manufacturer, and the manufacturer also sets requirements for the extraction system. The extraction flow rate for cast iron blast machines should be around Q= 3000 – 10 000 m3/h per machine.

Dedusting of shot blasting chambers

Blasting chambers are used for surface treatment of large cast iron castings. Blasting is performed manually by a worker using a pressure nozzle with compressed air and the abrasives. Blasting chambers are very demanding for consuption of extraction flow rate. Air and dust extraction is done by suction grills located at the bottom of the blasting chamber, drawn through the ducting into the baghouse, and the cleaned air is then returned to the top of the blast chamber. Determination of the extraction flow rate is based on the volume of the blasting cabin – the air should be replaced 100 to 150 times per hour. The extraction flow rate therefore ranges from 10,000 to 100,000 m3 / h, according to the size of the blasting box.

Dedusting of cast iron grinding –  large spaces

The extraction is carried out in the grinding shop floor by means of concrete extraction channels. The lower extraction of the grinding workplace is carried out in a closed grinding cabin, where air is extracted downwards, then carried by ducting into the baghouse where its cleaned and then returned to the grinding cabin ceiling. The airflow direction inside the grinding cabin upwards and at speeds of approx. 0.3 m / s. The extraction flow rate should range between 800-1000 m3 / h per 1m2 floor area of the grinding cabin. With respect to the large extraction flow rate requirement of the lower extraction method, it is recommended to separate the grind area into several sections separated from the extraction line by controlable valves, thus concentrating extraction flow rate into areas where it is required the most.

Dedusting of cast iron machining

When machining the castings by milling or turning, shred pieces and dust is spreading around the tool. Extraction in this case does not serve to extract the shred pieces but to eliminate the spread of dust particles to the surrounding area. The dust extracted is very fine, sticky and, if not sufficiently extracted can cause problems with wiring because it is electrically conductive.

Baghouse parameters

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience of cast iron dust extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter. The filter medium does not contain folds where the dust be sedimented and is very mechanically resistant to tearing or scraping. The amount of residual dust particles ranges from 1 mg/m3 to 5 mg/m3, which allows for cleaned air to be recirculated back into the plant for heating and to save on heating costs.

Recommended ducting solution

We recommend using Group III Ducting for cast iron dust extraction – a thick-walled, welded ducting. Pipeline components such as elbows, flaps, and branches are subject to abrasion from the dust particles and material fragments. Despite the thick walls of these components, it can not be ruled out that after a certain period of time they will be damaged by abrasion.

Baghouse units for cast iron dust extraction in the GIDLY catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Cast iron dust extraction“. In the next step, select the required volumetric airflow of the bag filter unit. The result will be a set of items – baghouse unit+ fan +  silencer box, all of which form a dedusting system. You can then insert the items into the costing.

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Bag filters for foundry dust extraction

Odsávání prachu ve slévárnách

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In our catalog we have included filter units that are by design directly made for use in foundry dust extraction applications. This specific dust is emerging when working with coal. Our catalog includes 18 basic baghouse units for foundry dust that forms an explosive atmosphere with air. The bag filter units are graded according to the required volumetric airflow.

Foundry dust characteristics

Among the foundry dust in this filtering group are specks of dust that are created when handling the foundry sands, when regenerating the sands and when shot blasting the castings. The most common applications of dedusting are related to knockout machines, sand coolers, conveyor drifts, elevators, pneuconveying vents, sand cleaner, shot blasting machines and others. The Foundry dust is very abrasive, rough and heavy.

Foundry dust extraction

Dedusting of knockout machines

The knockout machine is one of the major sources of dust in foundries. For the extraction of foundry dust, this task is very specific, because it is necessary to provide dust extraction from a relatively large space of the knockout machine where the castings are loaded by a crane. Knockout machines are thus often enclosed in cabins to ensure efficient dust extraction. The castings are mostly hot and the released dust tends to quickly climb upwards to the top of the box. The extraction is designed so that the extraction occurs at the top of the box and at the sides near the crane rope grooves.  The required extraction flow rate is determined by the size of the knockout machine and ranges around Q = 20000 – 30000 m3 / h for smaller knockout machines and 50000 – 80,000 m3 / h for larger ones.

Foundry sand cleaner machines dedusting

The foundry sand cleaner machines have an important task to keep the required sand quality for its another use. They are always included in the technological system of sand regeneration.  This is a specific task for the extraction system because the cleaner machines are very sensitive to an extraction flow rate difference which directly influences the proper function of the cleaner. We recommend that the extraction flow rate is controlled with a vacuum sensor in the ducting, placed directly behind the cleaner. The fan thus increases/decreases its RPM so that the airflow conditions are as constant and invariable as possible on factors such as fluctuating pressure drop of the bag medium, the amount of dust extracted, and others. The extraction flow rate for each type of cleaner is usually determined by the manufacturer of the technology and ranges from about 5,000 to 10,000 m3 / h, and maybe even higher.

Conveyor and elevator drift dedusting

Usually, belt conveyors and elevators are used to handle foundry sand. Sands are transported over relatively long distances, and these transport paths form a link between knockout machines and sand regeneration technology. The biggest dust sources in belt conveyors are their drifts. In the drift, whether it is a transfer between belt conveyors or an inlet/outlet to the elevator, there is a significant leakage of dust into the surrounding area. The dust extraction is then carried out by connecting the extraction pipe to the cover, which is built around each draft. For larger conveyors and drifts that reach through each floor, it is necessary to provide extraction both in the top and bottom of the cover. The extraction flow rate is designed according to the width and speed of the individual conveyor belts and ranges from 1500 to 5000 m3 / h per drift

Shot blaster dedusting

Blast machines are used for basic cleaning of the cast iron casting from foundry sand residues. In the blasting process, both the abrasive particles from the blasting machine and some of the sand and cast iron dust get into the extraction dedusting system. Separators are therefore included in the extraction ducting to ensure that only the dust particles of the cast iron are filtered by baghouse and the abrasive recirculates in the blaster only. The blasting machine is usually pre-equipped with dust separators from the manufacturer, and the manufacturer also sets requirements for the extraction system. The extraction flow rate for cast iron blast machines should be around Q= 3000 – 10 000 m3/h per machine.

Shot blasting chambers dedusting

Shot blasting chambers are used for surface treatment of large cast iron castings. Blasting is performed manually by a worker using a pressure nozzle with compressed air and the abrasives. Blasting chambers are very demanding for consumption of extraction flow rate.  Air and dust extraction is done by suction grills located at the bottom of the blasting chamber, drawn through the ducting into the baghouse, and the cleaned air is then returned to the top of the blast chamber. Determination of the extraction flow rate is based on the volume of the blasting cabin – the air should be replaced 100 to 150 times per hour. The extraction flow rate, therefore, ranges from 10,000 to 100,000 m3 / h, according to the size of the blasting box.

Specification of the filtration medium

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience of foundry dust extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter. The filter medium does not contain folds where the dust is sedimented and is very mechanically resistant to tearing or scraping. The amount of residual dust particles ranges from 1 mg/m3 to 5 mg/m3, which allows for cleaner air to be recirculated back into the plant for heating and to save on heating costs. The solids are collected into a big bag or a steel container with the help of a rotary valve.

Recommended ducting solution

We recommend using Group III Ducting for foundry dust extraction – a thick-walled, welded ducting. Pipeline components such as elbows, flaps, and branches are subject to abrasion from the dust particles and material fragments. Despite the thick walls of these components, it can not be ruled out that after a certain period of time they will be damaged by abrasion.

Baghouse units for foundry dust extraction in the GIDLY catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Foundry dust extraction“. In the next step, select the required volumetric airflow of the bag filter unit. The result will be a set of items – baghouse unit+ fan +  silencer box, all of which form a dedusting system. You can then insert the items into the costing.

 

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Bag filters for automatic grinding machines

Odsávání od andromatů

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In our catalog we have included filter units that are by design directly made for filtering of non-explosive grinding machine dust. Our catalog includes 16 basic baghouse units graded according to the required volumetric airflow.

Parameters of dust resulted from automated machine grinding

Automatic grinding machines are working with high efficiency and speed. The extracted dust is marginally different to the dust resulted from manual grinding. Due to the high speeds of the grinding process, the resulted dust is formed by coarse material particles and also the abrasive material of the grinding wheels. At the same time the extraction of the very fine flue-like dust occurs. This dust resulted from the high temperature during the grinding process. Very fine dust causes a high load on the bag filter, which must ensure its continuous operation without significant pressure drops which would have an effect on the extraction efficiency.

Dedusting of automatic grinding machines

Grinding machines are already equipped with suction hoods from the manufacturer. Manufacturers often recommend the minimum required extraction speed in the suction nozzle. Frequently the required suction speeds are around 30 m / s. When designing pipeline routes, it is advisable to extend the suction line along the suction extension so that the resulting suction line speed is 20-22 m / s.  At the same time, it is not advisable to choose the naturally shortest way of the ducting line into the baghouse, as with the dust a large number of sparks are sucked into the ducting line, which can cause a fire in the baghouse. When the sparks come into contact with the ducting, they lose a part of their heat energy and can go out easily, especially in ducting elbows. It is very appropriate to include a minimal of 3 to 5 90°, 1,5D radius elbows in the ducting to protect the baghouse from a possible burning.

Baghouse parameters

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience with individual grinding dust extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter. The filter medium does not contain folds where the dust be sedimented and is very mechanically resistant to tearing or scraping. The amount of residual dust particles ranges from 0,25 mg/m3 to 1 mg/m3, which allows for cleaned air to be recirculated back into the plant for heating and to save on heating costs. The bag filters are equipped with an integrated pre-separator for rougher particles and sparks so that these particles are knocked down right into the hopper and they dont come into contact with the filter bags.

Recommended ducting solution

We recommend to use ducting made of combination of Group II straight pipes and Group III for other parts (elbows and branches). The use of flanged joints is neccesary. Please note that this type of extracted dust is abrasive and is subject to a high amount of wear. Some parts may eventually need to be replaced or refurbished. The increase of steel thickness on these components can only extend the lifetime but wont stop the abrasion.

Baghouse units for automatic grinder machine dust extraction in the GIDLY catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Automatic grinding machines dust extraction“. In the next step, select the required volumetric airflow of the bag filter unit. The result will be a set of items – baghouse unit+ fan +  silencer box, all of which form a dedusting system. You can then insert the items into the costing.

 

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Bag filters for steel polishing dust extraction

Odsávání od leštění kovu

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The Gidly Catalog includes bag filters designed for use with polishing paste. Our catalog includes 18 basic baghouse units graded according to the required volumetric airflow.

Parameters of dust resulted from steel polishing

When polishing steel materials, dust particles are released into the workspace that the workers come into contact with. The dust is made up of steel particles, polishing paste and fibers from the polishing wheel. The dust is slightly abrasive, combustible and due to usage of the polishing paste also explosive. After filtering, the powder is soft, fibrous, light, sticky and tends to form clumps. Due to the polishing paste and the polishing wheel fibers content, there is a possibility of burning.

Dust extraction

Dedusting through the covers of polishing wheels

Is the most effective method of dust extraction. The dust particles are extracted by the covers on the polisher wheels. The connection of the polisher to the central suction duct is made using a flexible hose. The correct determination of extraction flow rate is in practice somewhere in the following values: With polishing wheels up to a diameter of 200 mm is recommended to set the flow rate to at least 600 m3/h and for wheels with diameter from 200 to 300 mm flow rate of at least 1000 m3/h, for diameters of 300 – 400 mm at least 1400 m3/h  and with atypical wheels, the determination is always individual.

Dedusting of automatic polishing machines

From the point of extraction and determination of the required flow rate, it is always neccessary to meet the requirements of the polishing machine manufacturer. The dedusting with its correct funciton ensures extraction of the explosive dust which would otherwise sediment in the inner cabin space and could result in forming an explosive atmosphere. The emergence of an explosive atmosphere inside the polishing cabin is needed to be avoided by regural cleanup so that the unextracted dust will not form sediments in the corners. Generally speaking, the extraction flow rate of the polishing cabin needs to be chosen rather higher than lower. Even with the smallest cabins, the flow rate starts at 5000 m3/h and more.

Parameters of dust extraction

When designing the extraction system, it is neccessary to follow at least these basic rules: Extraction ducting must be properly electrically connected through each components – from the extraction cover/hood to the baghouse. The whole system must be properly grounded. The baghouse must be equiped with proper explosion vents directed into a safe location. The filter housing must be pressure resistant, the bag medium must be antistatic. The exhaust duct must be fitted with a non-return backflap valve to prevent baghouse explosion spreading into the suction line, and the suction ducting flow rate must not fall below 20 meters per second.

Parameters of baghouse for polisher dedusting

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience of individual extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter. The filter medium does not contain folds where the dust be sedimented and is very mechanically resistant to tearing or scraping. The amount of residual dust particles ranges from 0,25 mg/m3 to 1 mg/m3. The baghouse design allows for filtered air to be recirculated back into the workshop and to save on heating costs during winter months.

When returning the filtered air, it is necessary to place a residual dust sensor in the exhaust pipe so that the purity of the filtered air can be continuously monitored. If the set dust limit should be exceeded, the system must shut down immediately or switch the exhaust to the outdoor environment without delay. The filtering device must be positioned so that the explosion vents are directed into a safe space.

Recommended ducting solution

In polishers dedusting, we recommend to use ducting made of combination of Group II straight pipes and Group III for other parts (elbows and branches), with the use of flanged joints.  This combination is recommended due to the extraction of an abrasive dust, wearing the places of airflow direction change the most = elbows and branches. It is neccesary to avoid riveted joints at all costs – the inner ducting space must remain smooth on the whole pipeline. Any sharp edge inside the ducting will result in the fibers clogging up the pipe. The part of the ducting between the baghouse unit and the backflap valve must be made of a pressure resistant pipe Group II or Group III.

Bag filters for steel polishing dedusting in the GIDLY catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Polishing with a paste – EX“. In the next step, select the required volumetric airflow of the bag filter unit. The result will be a set of items – baghouse unit + explosive dust precautions + fan +  silencer box, all of which form a dedusting system. You can then insert the items into the costing.

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Bag filters for grinding

Odsávání při broušení

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The Gidly Catalog includes bag filters directly designed to be used for extraction of non-explosive grinding dust. Our catalog includes 18 basic baghouse units graded according to the required volumetric airflow.

Parameters of dust resulted from grinding

When grinding steel materials, dust particles are released into the workspace that the workers come into contact with. Grinding dust is made up of metallic particles, rust and grinder particles. The dust is abrasive and with iron materials also non-explosive. After filtering, dust is coarse, heavy and partially oily. Because grease is contained , there is a possibility of burning.

Extraction of steel material grinding

Extracting right at the dust source

Is the most effective capture method. The dust particles are extracted by means of positioning arms or stationary hoods. Unfortunately, the workers frequently do not use the extraction arms, or they do not properly position them, as this is an extra work for them – largerly with sizable workpieces. The dust extraction hoods are successfully used at work benches where smaller workpieces are abraded. The suction hood provides dust extraction so that the worker does not come into contact with the dust extracted away from the worker. For smaller extraction arms we reccomend a suction power of 1000 – 1200 m3/h for one extraction arm and for suction hoods 1500 – 2000 m3/h per 1 meter of hood lenght.

Lower extraction – through the floor

This solution is used on larger working spaces where the extraction at the worktable is not possible because the workpiece needs to be accesible from all sides. The extraction is built into the floor of the grinding shop and the dust is extracted through concrete extraction canals.  The lower extraction of the grinding workplace is usually carried out in closed grinding cabins, where the polluted air is sucked down, followed by a baghouse where the dust particles are filtered out and then returned to the top of the grinding cabin. The airflow direction inside the grinding cab is from the top to the bottom – the recommended speed is about 0.3 m / s. Extracting suction power is recommended between 800-1000 m3 / h per 1 square meter of the grinding cabin floor area. Due to the high suction power requirement for the floor extraction system, it is recommended to divide the grinding workspace into several sections separated in ducting by valves, so that suction power can be concentrated in areas where it is required.

Bag filter specification

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience of cast iron dust extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter. The filter medium does not contain folds where the dust be sedimented and is very mechanically resistant to tearing or scraping. The amount of residual dust particles ranges from 0,25 mg/m3 to 1 mg/m3, which allows for cleaned air to be recirculated back into the plant for heating and to save on heating costs.

Recommended ducting solution for grinding dust

With manual grinding dedusting, we recommend to use ducting made of combination of Group II straight pipes and Group III for other parts (elbows and branches), with flanged joints. This combination is recommended due to the extraction of an abrasive dust, wearing the places of airflow direction change the most = elbows and branches.

Baghouse units for manual grinding dust extraction in the GIDLY catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Manual grinding“. In the next step, select the required volumetric airflow of the bag filter unit. The result will be a set of items – baghouse unit+ fan +  silencer box, all of which form a dedusting system. You can then insert the items into the costing.

 

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Bag filters for welding shops

Odsávání od svařovacích automatů

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The Gidly Catalog includes bag filters directly designed to be used for extraction of welding smokes and aerosols. Our catalog includes 18 basic baghouse units for welding shops graded according to the required volumetric airflow.

Parameters of smoke resulted from welding

Smokes that are emerging when welding are very harmful to health, and therefore its very neccessary to use an effective extraction system to preserve the worker’s health.  When welding stainless steel parts, nickel, chromium and other heavy metals are present in the smoke. These elements have undesirable cancer-causing effects on the human organism. When exhausting into the environment without filtration, the are will be polluted with dust and rust. After filtering, the dust resulted from the smoke is very fine, light and oily. Because grease is contained , there is a possibility of burning.

Capturing the welding smoke

Capturing the smoke near the source

Is the most effective capture method. The smoke is extracted by means of positioning arms or stationary hoods. Unfortunately, the workers frequently do not use the extraction arms, or they do not properly position them, as this is an extra work for them – largerly with sizable workpieces. The dust extraction hoods are successfully used at work benches where smaller workpieces are welded. The suction hood provides dust extraction so that the worker does not come into contact with the smoke and there is no need to use an air mask. For smaller extraction arms we recomend extraction flow rate  from 1000 to 1200 m3/h per one arm and for suction hoods 1200 – 1500 m3/h per 1 meter of hood lenght.

Capturing the smoke with an extractor hood

Used at larger workspaces, where its not possible to extract near the source. The hood is located directly above the welding workstation. This is the workplace of manual or robotic welding. We recommend setting the extraction flow rate to 600 – 800 m3/h per 1m2 of extraction hood. For robotic welding we recommend extraction flow rate of 800 – 1000 m3/h per 1m2 of extraction hood. In the case of manual welding, the welding smoke unfortunately comes into contact with the worker sooner than it is extracted by the hood. The extractor hood serves to stop spreading the smoke further into the welding shop area, but it wont protect the health of the worker himself. The usage of extractor hoods does not rule out the usage of personal protective equipment, such as air masks.

Spatial welding smoke extraction

This is used for sizeable welding shops where the usage of suction hoods or arms is not possible. This is mainly a workplace where the welding workpieces are handled by bridge cranes. Exhaust duct is located between the ceiling of the hall and the crane track. It is always good to design the suction duct so as to ensure extraction of dust above the welding compartment, not above the corridors, storage, etc. Since welding smoke is caught in the space above the ceiling, welders are exposed to welding smoke and the spatial smoke extraction does not rule out the usage of personal protective equipment, such as air masks. The extraction flow rate needs to set for each individual application, with respect to sizes and layout of welding workspaces, welding intensity and the height of the plant ceiling.

Parameters of bag filters for welding shops

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience of welding shop extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter. The filter medium does not contain folds where the dust be sedimented and is very mechanically resistant to tearing or scraping. The amount of residual dust particles ranges is 0,25 mg/m3  at the worst case scenario, which allows for cleaned air to be recirculated back into the plant for heating and to save on heating costs. If the welding shop is not equipped with a sufficient air conditioning system for feeding clean air, we recommend to replace a part of the extracted filtered air with an outside air with usage of a heat exchanger.

Recommended ducting solution

When extracting air from welding shops, we recommend to use spirally wound ducting of Group I for straight pipes, elbows and even branches of Group I folded and galvanized. The dust and smoke is not abrasive, so the ducting wont be subject to any wear.

Baghouse units for welding shops in the GIDLY catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Welding shops“. In the next step, select the required volumetric airflow of the bag filter unit. The result will be a set of items – baghouse unit+ fan +  silencer box, all of which form a dedusting system. You can then insert the items into the costing.

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Bag filters for welding shop ambient ventilation

Prostorové odsávání ve svařovnách

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The Gidly Catalog includes bag filters directly designed to be used for spatial extraction of welding shops, ie extraction of welding smokes and aerosols. Our catalog includes 18 basic baghouse units for welding shops graded according to the required volumetric airflow.

Parameters for welding shop ambient ventilation

Ambient ventilation of welding shops is succesfully applied at plants where the welding smokes cannot be extracted near their source. Local extraction solutions, such as extractor hoods or arms cannot be used here. The common application of this technology are welding shops where manipulation with bridge cranes occurs and the usual local extraction methods cannot be used. The spatial extraction ensures capture of the welding smokes in the area under the plant´s ceiling – usually above the bridge crane track. The extraction is ensured by a central ducting with grids. These grids are distributed so that they maintain an air extraction effect right over the welding smoke source.  The central ducting is led into a bag filter device, which provides filtration of the air. The filtered air is then distributed back into the plant.  If the welding shop is not equipped with a sufficient clean air intake system, it is possible to join these two technologies together and run the filtered air into a heat exchanger air conditioning unit. Fresh air will then be exhausted into the plant through this unit and replace the spent air.

Filter unit specification for ambient ventilation usage

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience of welding shop extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter. The filter medium does not contain folds where the dust be sedimented and is very mechanically resistant to tearing or scraping. The amount of residual dust particles ranges is 0,25 mg/m3. We are often encountering users with negative experiences, complaining to the need of frequent and expensive replacements of folded filter elements. From this reason, our catalog includes a type of a bag filter technology that guarantees lifetime of the filter elements to at least 20 000 operating hours, without the need of any manual refinement or cleaning. We hold an opinion that the filter technology should serve the user, not the other way around.

Recommended ducting solution for welding shops

When extracting air from welding shops, we recommend to use spirally wound ducting of Group I for straight pipes, elbows and even branches of Group I folded and galvanized. The dust and smoke is not abrasive, so the ducting wont be subject to any wear.

Bag filters for ambient welding ventilation in the GIDLY catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Welding shops“. In the next step, select the required volumetric airflow of the bag filter unit. The result will be a set of items – baghouse unit+ fan +  silencer box, all of which form a dedusting system. You can then insert the items into the costing.

 

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Common mistakes in aplications of dust extraction

The most frequent mistakes that we occasionally find in the dust extraction systems of dedusting suppliers, both in the design and in the implementation phase are:

Inappropriately chosen extraction flow rate

This mistake can be easily identified due to the dusting of the extracted places when the exhaust system is switched on in the case of undersize extraction flow rate. Another possibility is the disproportionately high power consumption of the exhaust system with an over-sized extraction flow rate. We discuss the issue of proper extraction flow rate design in a separate chapter of our Academy –  „Determining the right amount of extraction flow rate for different dust types

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Determining the correct extraction flow rate for different dust types

Determining the right amount of extraction flow rate is the first step in solving any dust extraction project and is crucial to the proper function of the system. If a wrong determination of the flow rate occurs – in the worst case its under-dimensioning – the project is invaluable right from the start-up. Ductings and low-capacity baghouse technologies will be designed, constructed and installed, which will be immediately apparent when you start the system itself. The repair cam be very expensive, sometimes needing even a complete replacement of the entire technology. The design of the flow rate is best to be checked with more experienced designers or suppliers before you move into the realisation phase.

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Bag medium lifetime

Focusing on the operating costs associated with the use of dust extraction and filtration technology, it is necessary to include not only the electricity costs. Another operating costs are induced by compressed air for filter medium regeneration and refurbishment costs. It is also important to focus on the lifetime of the bag media and other important parts of the dust extraction system and the cost of replacing them.

For baghouse extraction system, one of the most costly, periodically variable parts is the bag medium itself. The bag media has different, manufacturer-defined lifetimes for different types of filtering devices.

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Optimal baghouse pressure drop

 

The reason to focus on optimizing pressure drops in the dust extraction system is that each excess pascal – pressure loss – is manifested by an increase in operating costs for the operation of the extraction  fan. The pressure losses of the ducts are discussed in a separate chapter. The largest pressure drop of the entire system is caused by the bag filter itself.

To save the operating costs of the dust extraction system, it is most important to choose a bag filter of a design that ensures the required suction power is maintained at the lowest pressure drops of the filter medium.

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Determining the correct elbow type

Selecting the correct type and radius of elbows is very important for balanced pressure conditions in the air extraction and dedusting system. Generally speaking, when choosing the correct elbow for dust extraction we decide on two requirements:

  • Requirement of the lowest possible ducting pressure drop
  • Requirement of the elbow durability

Continue reading Determining the correct elbow type