Overview of Main Points

This guide explains how to evaluate a gas filter manufacturer before placing an order. It covers the gas stream details to be gathered, filter types and filtration ratings, materials of construction, technical range, customisation, common selection errors, maintenance and the questions to put to a supplier.

Why the Choice of Manufacturer Matters

A Gas Filter removes dust, sand, rust, oil, moisture and other contaminants from a gas line before they reach downstream equipment. In refineries, power plants, chemical units and similar facilities, contaminants in the gas can damage valves, compressors, burners and instruments.

A poorly selected filter leads to frequent pressure drop, unplanned downtime and loss of output. For this reason, the manufacturer should be chosen on technical capability, build quality and support, and not on price alone.

Define Your Gas Stream First

Before approaching any manufacturer, the buyer should have the process details ready. A reliable supplier will ask for these in any case.

The key details are the line size, flow rate, operating pressure, operating temperature and the filtration rating required. The type of gas, whether it is compressed air, nitrogen or process gas, should also be stated, along with the contaminants to be removed. If the gas is corrosive, this must be mentioned, as it decides the housing material.

Incomplete information is the most common reason for a wrong recommendation. A short data sheet prepared at the start saves considerable time later.

Filter Types and Filtration Ratings

Gas filters are generally grouped by the job they perform.

Particle removal filters are used to remove dirt, dust, rust and metal particles, typically down to about 1 micron.

High efficiency filters remove oil, moisture and very fine particles, with ratings going down to 0.01 micron. These are used where the gas must be clean for sensitive downstream equipment.

Carbon filters are meant for oil vapour, taste and odour, and are chosen when vapour-phase contamination is the concern.

The manufacturer should be able to explain which type, or which combination, suits your process. Where moisture is heavy, a scrubber system for moisture separation may also be required. Overall filtration ratings from a capable supplier can range from 0.01 micron to 6000 micron, which covers both fine polishing and coarse cleanup.

Materials and Housing Construction

The filter element and the housing are both important.

Filter media may include paper, synthetic, polyester, polypropylene, coalescing media, borosilicate glass fibre, activated carbon, non-woven material, stainless steel wire mesh, sintered bronze, sintered wire mesh and sintered powder. The right media depends on the contaminant and the required micron level.

The housing may be made of aluminium, carbon steel or stainless steel. For standard construction, grades such as CS, MS, SS304, SS304L, SS316, SS316L and SS317L are used. The choice depends on operating pressure and on how corrosive the gas stream is. Stainless steel grades are preferred for corrosive service, while carbon steel suits many general applications.

Ask the manufacturer to justify the material recommended for your conditions.

Technical Range to Verify

A good manufacturer should be able to cover a wide operating envelope. As a reference, GTS Filters and Systems lists the following range for its gas filters:

  • Line size: ¼" NB to 30" NB
  • Operating pressure: 0 to 50 bar
  • Operating temperature: 15°C to 500°C
  • Flow rate: up to 80,000 NM³/hr and more
  • End connections: flanged (150# and 300#), Table E and Table F flanges, DIN flanges, butt weld, NPT/BSP threaded and other connections

Whichever supplier you consider, compare their stated range against your actual site figures. A narrow range may mean your requirement has to be forced into a standard design, which affects performance and life.

Customisation and Vessel Replacement

Many plants have unique process conditions. A manufacturer that offers customisation can design the filter around your flow, pressure and temperature, instead of asking you to adjust the process.

Replacement of existing vessels is another point to check. Older vessels can be replaced with modern designs having a larger filtration area, lower pressure drop and longer service life. This is useful for plants that wish to upgrade without redesigning the whole line.

Ask whether the manufacturer can supply drawings and a clear specification for a customised filter before manufacture begins.

Industry Experience and Testing

Experience in your industry matters. Gas filters are used in refineries and petrochemicals, power plants, oil and gas, chemical industries, steel, cement, fertilisers, pharmaceuticals, textiles, food and dairy and several other sectors. Each has different gas conditions and standards.

Ask for details of similar installations. A manufacturer with around 25 years of experience, as GTS Filters and Systems states, will usually have handled a wide variety of conditions and can anticipate problems.

Also confirm that the filters are tested and designed in line with current industrial standards. Request test certificates and material test reports where your project requires them.

Common Selection Errors

Several errors are seen again and again in gas filter purchases.

Selecting on price alone. The cheapest filter may have a lower filtration area, causing early clogging and frequent replacement.

Wrong micron rating. A rating that is too coarse lets contaminants through. One that is too fine causes rapid pressure drop and short element life.

Ignoring pressure drop. A high pressure drop raises energy cost and reduces flow. Pleated configurations help here, as they give a larger filtration area and lower resistance.

Incorrect housing material. Using an unsuitable material in a corrosive stream leads to early failure of the housing.

Incomplete data. Submitting an enquiry without flow, pressure or temperature leads to a mismatched design.

Maintenance and Support

A gas filter needs regular attention. The differential pressure across the filter should be monitored, since a steady rise indicates that the element is loading up and needs cleaning or replacement.

Elements should be replaced on schedule, and housings inspected for corrosion and leakage at the seals. Records of each change help in planning stock of spares.

Before ordering, find out how the manufacturer supports its customers. Check the availability of spare elements, delivery time, technical guidance and response to service requests. A supplier who supports the product after delivery reduces your total cost over its life.

Questions to Ask Your Manufacturer

The following questions may be put to the supplier before an order is finalised:

  • Which filter type and micron rating do you recommend for my gas stream?
  • What housing and media materials are suitable for my conditions?
  • What are your limits for line size, pressure, temperature and flow?
  • Can the filter be customised to my parameters?
  • Can you replace or upgrade my existing vessel?
  • Are the filters tested, and can test reports be provided?
  • What are the delivery time and the availability of spare elements?

Clear and specific answers will show how capable the manufacturer is.

Requesting a Recommendation

Before approaching a manufacturer, note down the line size, flow rate, operating pressure, temperature, gas type, contaminants and required filtration rating. Share a simple data sheet or drawing and ask for a written recommendation. Compare offers on technical fit, construction and support, and not on price alone.

GTS Filters and Systems Pvt. Ltd, based in Vadodara, Gujarat, manufactures a range of gas filters including dry gas filters, nitrogen gas filters and oil mist filters, along with filter housings, cartridges and complete systems. Buyers are welcome to share their process details with the team and request a suitable recommendation.

Frequently Asked Questions

Q. What details should be shared before ordering a gas filter?
Ans. The line size and flow rate are needed first, followed by operating pressure and temperature, the required micron level and the housing material. The type of gas and the contaminants should also be stated.

Q. What is the difference between particle removal, high efficiency and carbon filters?
Ans. Particle removal filters handle dirt, dust and rust down to about 1 micron. High efficiency filters remove oil, moisture and fine particles down to 0.01 micron. Carbon filters are used for oil vapour, taste and odour.

Q. Can a gas filter be customised?
Ans. Yes. A capable manufacturer can design the filter according to your process parameters. Share the flow, pressure, temperature and gas details so the team can suggest the right design.

Q. Can an existing filter vessel be replaced or upgraded?
Ans. Yes. Older vessels can be replaced with modern designs offering a larger filtration area, lower pressure drop and longer service life. The existing vessel details should be shared for a proper recommendation.