After the project was complete, the Managing Director said “It was nice to work with Darren and the team again after a few years since the install. The silo move was professionally managed and therefore trouble free to plant operations. We would consider the team again on future works.“

For this project, site wanted to free up some space and wanted to make access for tanker collections in an alternative position as the original silo tanker collection position was also a throughfare for production.

We were then also asked to design a bespoke access platform to allow maintenance on the filter separator located on the top of the existing silo.

The new access platform was to be incorporated into the silo body and the silo handrailing needed to be modified.

We carried out FEA analysis on the proposed platform to ensure it was as per BS6399 rated as ‘’for occasional personnel, small tools and light equipment’’.

Once the access platform had been confirmed as appropriate for the standard which requires a load of between 2.0 and 4.0 kN/m² we placed this into fabrication. The site wanted a quick turnaround on this, and we managed to fabricate the access platform and get it galvanised in just under a month.

Prior to relocating the silo, we needed to remove the bellows system:

And the inclined screw:

We had allowed a week on site, with 3 days of contract crane lifts.

The seven year old silo continues to collect ash from the aluminium furnaces filtration plant, ready for tanker discharge – reducing labour involvement in removing the ash from the process continually.

The post Project H – Silo Relocation and Platform Addition appeared first on Filter Designs.

Formerly known as Salisbury Axles, the facility once manufactured components for the British car industry including iconic models such as Aston Martin’s early DB car, a hallmark of British automotive engineering.

Historic Salisbury Transmission advert for Aston Martin DB2 & DB3 (circa 1952)

Today, that same site has transformed into a modern production hub, housing robotic welding booths and a forward-thinking approach to workplace safety and environmental control.

This case study tells the story of how three cartridge filters, installed as part of a custom-designed Local Exhaust Ventilation (LEV) system, now manage the air quality across three robot welding cells— protecting the workforce while respecting the legacy of Birmingham’s iron and fire past. Along the way, we draw parallels between heavy industry and heavy metal, exploring how echoes of the past continue to shape the city’s future.

Birmingham has long been Britain’s beating industrial heart. This factory that now supplies vehicle components to British and European manufacturers was once home to Salisbury Transmissions, later Salisbury Axles — a cornerstone of the UK’s post-war automotive revival. Among its most famous clients was Aston Martin, which sourced components from the site for its DB2 line in the early 1950s. These vehicles blended luxury and power, and the axles beneath them carried the force of an industry rebuilding itself from wartime ashes.

Now acquired by our client, a global leader in drivetrain and e-propulsion systems, the plant now serves the ever-evolving needs of the automotive sector — a technically advanced company, where robotic welding machines on the shopfloor ensure the highest possible standards are met each and every time.

Robotic welding might seem cleaner than manual welding, but the reality is different. Despite the precision of machines, the chemical byproducts remain the same — manganese, chromium, iron oxide, and nitrogen oxides hang in the air long after the arc is extinguished.

Left unchecked, these fumes pose severe risks to both health and equipment. The HSE (Health and Safety Executive) mandates strict control of such airborne contaminants. In 2024, the client committed to investing in a custom-designed LEV system to manage emissions from three of their busiest robotic welding booths

The solution comprised three high-capacity CleanPULSE cartridge filter units, each serving a separate robotic welding booth. Each filter unit was specified with self-cleaning filter cartridges, high-efficiency fans, and VSDs to modulate extraction.

Screenshots of our 3D design, using measurements taken on site for location of the filters.

Design Considerations

Key design challenges included:

• High Extraction Demand: Robotic welders operate in bursts but generate significant fume loads. Each booth required a robust extraction setup capable of handling peak volume.
• Accessibility and Maintenance: The system needed to be easy to service without disrupting production.
• Modularity: Future expansion was inevitable — the system had to be scalable.
• Aesthetic Integration: Though secondary, management also wanted a system that reflected the site’s commitment to modernisation.

The LEV Solution – Three Cartridge Filters, One Clean Future

System Overview

The final solution comprised three high-capacity cartridge filter units, each serving a separate robotic welding booth. Each filter unit was specified with:

• Self-cleaning filter cartridges with pulse-jet technology to maintain pressure drop and extend filter life.
• High-efficiency fans, mounted on vibration-dampened skids, rated for continuous operation at over 95% efficiency.
• Variable Speed Drives (VSDs) to modulate extraction rates based on welding activity, conserving energy during idle periods.

Ductwork and Controls

A network of galvanised steel ducting, with flexible hose drops into each robotic cell, connected the booths to their respective extraction units. The controls featured:

• Automated start/stop, triggered by welding activity.
• Local fault indicators at each booth.
• A central control panel for facility management, allowing live system monitoring and logging.

Installation and Commissioning

Installation was carried out in two phases over three weeks to minimise downtime. Pre-commissioning checks included:

• Airflow measurement at source hoods.
• System balancing.

Birmingham isn’t just known for making metal — it invented heavy metal. In July this year, just around the corner from this factory, so close to where (the late) Ozzy Osbourne grew up and with his band Black Sabbath, took his final bow at Villa Park such a short time before his recent sad passing. The band’s music was forged in the same crucible as the city’s industry, their sound mirroring the thunder of forges and the daily grit of Birmingham’s workers.

Employees note that while the plant now operates with robotic precision, it echoes the spirit of the city’s industrial and musical past (though not too loudly, thanks to the ducted sound attenuators we included in the outlet ducts off each fan). The LEV system represents progress: a modern response to old risks — one that puts people and the planet first.

Investment in LEV technology isn’t just about keeping the workplace tidier it’s a legal requirement for compliance —A statement that a site steeped in the glory of British automotive history can also stand at the cutting edge of a modern workplace.

Just as the Aston Martin DB2 represented a leap into the future, so too does this modernised welding line. The cartridge filters don’t just extract fumes — they extract a cleaner, safer, more responsible future for the employees. Below is our smoke capture test.

This LEV project is a blueprint for how old industrial sites can rise to new challenges — not by abandoning their past, but by building on it. Just as Sabbath closed their final concert a few hundred metres away, the last chords of yesterday’s industry are giving way to a new kind of power: cleaner, smarter, and no less mighty.

In the end, whether it’s an axle or an anthem, Birmingham still knows how to deliver heavy metal.

The post Project DA – From Heavy Metal to Cleaner Air: LEV evolution at the historic Salisbury Site appeared first on Filter Designs.

The fabric filter top sections had been modified back in 2023 where the bag length had been reduced from 6.5m to 4.26m and the pulse tanks have been changed to 8’’ tanks with 1.5’’ double diaphragm valves.

As the tanks were struggling to pulse clean the bags causing high dP the operators had turned up the compressed air from 4 bar (FD standard) to 7 bar.

The issue with this is:

1. Bags will degrade quicker due to excessive compressed air pressure
2. Causes an adverse effect as the dust is known to be fine and potential for re-entrainment (this is where the dust is pulsed off the bags then immediately sucked back onto the bags)

Prior to installing our new reverse jet pulsing system and to counter the second issue above as a precaution site were backing off the furnace to allow the filter to pulse clean down with less gas flow. This was taking approximately 15mins every 24 hours and was accounting for £1.5 million in lost revenue per year.

The current set up before our changes were:

8’’ tanks which have an air volume of approx. 43.30 litres (compressed). With each pulse shot consuming 169,90 litres (uncompressed).

We felt that the pulse tanks and pulse valves were undersized for this application and as an example we used the filter we installed on the same site back in 2023 Partial Offline cleaning Filter which had 8’’ tanks with 1.5’’ double diaphragm valves and each pulse valve only needs to clean a surface area of 14.67m² rather than the 24.75m² on this filter.

We therefore decided to increase the tanks from 8’’ to 10’’ and making the valves 2’’ will give and increased tank volume of 69,90 litres (compressed) and pulse shot of 275,60 litres (uncompressed).

Originally the modified top section had 2 8’’ pulse tanks per filter section (3) which meant 6 tanks in total.

As we increased the pulse tanks from 8’’ to 10’’ and the valves from 1.5’’ to 2’’ we could only fit 1 16-way tank in place rather than the (2) 8-way tanks.

The original cages were split due to the length and had an internal venturi which was causing a build up on the top 150mm of the bags causing high dP. We took a spare filter cage top and designed a cage to match but with our external venturi fitted to allow better cleaning. The new pulse tanks were to be fitted in the same place as the original tanks to allow us to re-connect to the existing compressed air pipe work and electrics (solenoids). This meant designing new support plates for the tanks and jet tubes along with pipe spools with unions. The old tanks were mounted on plates which needed cutting out to facilitate our new mounting plates with connecting spools.

The new 2’’ jet tubes were fitted with nozzles which improve pulse cleaning of the bags.

The installation was planned to take 10 days for 3 men. Due to circumstances out of our control we had to complete the installation in 6 days! This meant our installation team had to put longer hours to get the install completed before the site wanted to start back up, not to mention the 30+ degree heat up on top of the filter!

We set up a plan to complete all the hot works and complete a section at a time so that the client’s night shift team could install the bags and cages prior to us starting the next section which would alleviate the pressure on us.

As the new tanks were extremely large and very heavy, we need to use skates to get these into the building and use the overhead maintenance crane to lift this up onto the filter.

We had pre-arranged a scaffold to be placed above where the tanks were to be fitted to allow us to lift using chain blocks to safely into postion.

Photos of the completed installation:

The post Project ML2 – Fabric Filter Upgrade appeared first on Filter Designs.

After extensive interaction with the technical team based in India and revisions to the requirement specification, which is not uncommon for a pilot plant of this type, at Revision F we received an order for 2 filters and delivery to Denmark where the pilot plant would be built.

Below is the larger 6 x 6 CPCF 30 ‘Pre Heater’ filter

And smaller 4 x 4 ‘CPCF 13 Excess Air’ filter

The 2 filters were designed for quite different gas volumes but both would potentially be operating in the 400-425°C range. Each of the filter consists of 3 main 4mm thick mild steel pieces, (the hopper, the body with gas inlet and at the top the clean section with gas outlet). The complete filter housing sits on top of a galvanized support frame but is isolated from the frame by placing a heat isolation pad under each corner.

The heat isolation pads act as a break to conductive heat transfer. Isolating the support structure from the hot filter steel for safety and avoid the potential for cold spots in the filter where the heat bleeds out into the support and corrosion could occur. The header tank hangs off the top section via flanges which bolt through the 40mm thick heat isolation pads which isolate the tank from the heat of the process gases.  An adjustable height support sits below each tank.

On entry to the filter via the square inlet flange, the hot gasses first pass through a series of distribution plates which are CFD designed to distribute the gasses evenly across the filters and also promote downwards flow which aids the reverse jet cleaning action – CleanPULSE.   The distribution section also lowers the velocity and encourages larger particles to ‘fall out’ of the gas stream directly into the hopper.

The filter body includes the inlet flange and inlet distribution section above which is an access platform where you can access/service the pulse tank and differential pressure tapping points. Under the chequer plated access floor is a series of slabs of rockwool insulation.  The body is stiffened with a series of mild steel angles etc. 

A mild steel Cell Plate sits between the top of the main body and the top section above.  The filter elements sit in 6 rows of 6 for the larger ‘Pre-Heater’ filter and 4 rows of 4 elements for the smaller ‘Excess Air’ filter.

All the filter elements in both filters are off the same 1.8m length 150mm outside diameter irrespective of position in the cell plate. Both filters were designed and manufactured in accordance with EN1090 standards and certificated by the fabricators in Derbyshire. 

Prior to painting, a full test assembly was completed in order to ensure that when the filters arrived in Denmark we could be 100% certain they would be easily assembled by steel erectors with potentially zero previous experience of installing a filter.

A package of safety labels was provided and details of application locations given in the installation guide, these were part of the requirement for CE Marking the filters, required by the client along with the EN1090 certification.

High temperature paint finish was applied to the filter fabrications following trial assembly.  In this instance the filter has to be lagged and clad (on site by the client) for compliance. The handrailing, was painted, packed and labelled per filter for ease of installation on site

At the fabricators premises once each of the numerous pallets, boxes and fabrications was labelled, referenced according to filter, part number/drawing or the electrical component list by the project manager,  the full scope of supply was collected and taken to be packed prior to transportation to Denmark which was early 2025, after some delays to starting the project by HSBC establishing bank guarantees.

This project was delivered on time and budget to Denmark and is now in use.

The post Project FL – CleanPULSE CPCF Ceramic Filters for a Pilot Plant in Denmark appeared first on Filter Designs.

• Clinical Waste Incineration
• SNCR Skid
• Compressed Air and Urea Solution Control Panel
• 2 Bespoke Urea Injection Lances

We were originally contacted via a third party who were putting together a FEED study for an upgrade for a clinical waste incineration based at the Derriford hospital in Plymouth. The main order then subsequently came from Brothwell & Irvine who were the principal contractor who were overseeing the upgrades to the facility.

The specification we were given was:

Using our in-house reagent waste calculator where we can define the sorbent usage based on the raw gas emissions which was NOx in this case.

This spreadsheet can also give the client an approximate OPEX based on the current market prices.

The raw value we were given was to reduce the NOx from 400mg/m³ to 180mg/m³ as defined by the specification given (above) and to allow the site to comply with the BREF requirement for NOx emissions of >180mg/Nm³.

Once we knew how much urea is needed, we can then size the equipment needed to ensure these emissions are met.

The scope of the project is as follows:

• CleanNOx FIBC urea skid compromising:
• Duty / Standby Dosing pumps
• 3-way Diverter Valve
• Duplex Strainer
• Non return valves
• Urea pressure transmitter
• Air pressure transmitter
• Air regulators for Atomising / Barrier Air
• Mains Isolator
• MCB’s c/w Auxiliary trip contacts
• Control Relay’s
• Control Terminals
• Trip Indicator lamps on front of panel

• 2 Bespoke Urea Lances (one spare)
• 2 Urea spray nozzles
• 60m of EPDM hose including fittings

CleaNox control panel comprising:

• Rockwell Micrologix 1400 PLC System
• Our hardware offer is based on a Rockwell architecture
• Supply of all electrical hardware
• Rockwell Low Voltage Control Gear
• Network Switch

Our client provided us with a 3d model and CFD information so we could retrofit the lance into the ducting which would have the correct temperature requirements for the urea dosing and allow us to size the correct spray nozzle.

We then made the long trip down south to take measurements to facilitate the installation and determine where the SNCR skid and control panel would be sited.

Once the FAT on both the SNCR skid and control panel were completed these were sent direct to site and our client had their electrical installation team wire the skid to the control panel.

After a short delay we were then invited back to site to carry out the commissioning of the system.

Due to an issue with the site’s thermocouple reading incorrectly we had to force the temperature in the control panel so that the system would run, we had an interlock in the controls where the system couldn’t dose urea unless it was within the temperature range of 850°c – 1050°c.

Once the thermocouple was replaced, we were then able to log in remotely using the control panel IXON (remote access) to make the changes to the software without the need to visit site. This also allows us to check on the system and diagnose issues if they arise.

Stainless steel SNCR skid and control panel.

Bespoke ceramic coated urea lance with quick release fittings to allow quick removal from the ducting.

Bunded UREA IBC with quick release fittings and fitted with a float switch to identify when the urea IBC needed changing

Sites CEMS (continuous emissions monitoring system) to show us the NOx and Ammonia levels.

The system has been operating well since the install / commissioning and has reduced the NOx level set out in the specification given to us.

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The one tonne liquid copper capacity rotary furnace has an air volume of 25,000Am³/hr.

Our supply scope consisted of:

• CPB264 CleanPULSE reverse jet filter & ancillaries
• Centrifugal fan
• Rotary valve discharge into bulk bag
• Simple push button control panel with VSD & potentiometer
• Packing & Crating for sea freight

As this project was destined for Rwanda this was a supply only.

Due to the size of the filter, we needed to get it  crated for sea freight as it had to be shipped on an open top container and would be open to the elements.

The control panel was a simple push button panel which housed the inverter for the centrifugal fan with control via a pressure transmitter in the ducting or with a potentiometer. Due to the environment being potentially dusty we opted to also house the reverse jet pulse controller in the panel as well as the digital display for the thermocouples. The control panel was completely FAT tested prior to shipping and we provided an in-depth operational guide for the operatives on site.

Once the filter arrived the site installation team erected the filter using the installation guide we provided with associated drawings to facilitate.

Commissioning is yet to take place, but we are still in contact with our client and will offer support if and when it is needed.

The post Project MTR – Fume Capture Filter for a Copper Smelting Plant in Rwanda appeared first on Filter Designs.

An empty warehouse is always a welcome place to start a project.  This is because we have a blank canvas with which to design an ideal layout for a flue gas treatment plant.  Once installed, our system cleans the gases from a waste boiler and waste infeed plant and will allow the end user to stop transporting waste around the country and manage it locally, save on transport costs and produce some electricity too.

Our scope started at the boiler outlet flange and ended at the chimney entry flange.  CEMS, the chimney and compressed air were by others.  Therefore, our scope included:

CleanSPARK spark arrest box

CleanPULSE hot gas bag filter

CleanSORB sodium bicarbonate silo and ash silo’s

CleanPAC activated carbon rip and tip hopper

After a period of layout and design work and a detailed internal design review, with client GA approval fabrications commence and are then periodically checked as the project progresses.

Once the fabrications are ready and have been checked, they are loaded to heavy haulage.

Assembly is checked at the fabricators  premises to ensure correct fitting alignment, then loaded in whatever assembly orientation suits site installation.  In this case due to low roof height and the need to extract filter bags from the top access doors of the filter, we split the installation on the horizontal plane, sending the filter hopper, main case section and top sections separately.

The 4.2m diameter silo just fitted out of the fabricator’s roller shutter doors.  With the silo skated out to the front door, the hiab on the heavy haulage transport lorry is used, with outriggers spanning over the road

Due to the 4.2m width, the first part of the silo’s journey required a police escort. Then a long slow 8 hour journey to site where the first larger pieces of kit are offloaded.

The hiab is made use of again to offload on site.

The use of transport cranes to install the bigger bits of equipment is an efficient use of modern vehicles.  In this case two hiabs are used to offload and install the filter case section on top of the hopper.

The sodium bicarbonate silo installation was particularly tight.  Correct planning using load charts and known weights, considering the capabilities of the lifting equipment is essential.

Once the main equipment is in place it is insulated, clad and painted.  A lot of smaller works can then commence – suction lines, compressed air pipework, electrical connections, blow lines and some operator training.

In the adjacent warehouse which houses the boiler, the CleanSpark box is installed next to the boiler.  This directs the incoming gases, which could contain embers alight if boiler conditions are not optimal, through a torturous path and finally through a grid.  It is optimised for pressure loss using computational fluid dynamics software.  The CleanSPARK box has two hoppers to each discharge point, which are combined into one for discharge into a sealed skip.

With a whole warehouse section dedicated to flue gas treatment, the layout is ideal.  Drawing in the gases from the boiler room in the adjacent warehouse, we dose sodium bicarbonate and activated carbon.  Ash collected by the main filter is drawn up into an ash silo for low maintenance operation.

The ash silo collects around 38 tonnes of waste ash or APCR.  This reduces labour effort and allows the most efficient disposal route via tanker.  The silo has various dust discharge aids all controlled using compressed air and a tidy air management panel.  Silo internal weight is continuously monitoring using the load cells it sits upon.

The silo is then able to discharge to an APCR tanker outside using loading bellows.  These bellows have a pendant control which allows the bellows cone to be raised and lowered.  Once the tanker is in position, the bellows are lowered, an integrated reverse jet pulse filter provides extraction and the dust is discharged.  A rotating paddle level probe indicates when the dust level in the tanker is high and then the process can be repeated at the next tanker loading port.

With this work done, cold commissioning was progressed to prove all of the motors, instruments and valves.  Suitable analogue feedback values are checked from temperature probes, motor directions are proven, air pressure are set ready for hot commissioning. 

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