Filson Seal Gas Filter

  • Long service life and large dirt holding capacity
  • Available in single and duplex configurations based on your requirements
  • Comply with ASME , PED or other pressure vessel code on request
  • Inlet, outlet, drain and vent connections can be fitted to all industry standard connections
  • A wide size ranging from 1/2 inch to 4 inch in all pressure grades
  • Complete filter system design available to meet customer request

Filson seal gas filter contains vent and drain valves, differential pressure gauge, pressure safety or thermal relief valves. Its filter element material could be 316L stainless steel, fiber glass to suit various applications.

  • Construction material: glass fiber, 316L stainless steel
  • Dimensions: according to your final application
  • Coalescing efficiency: 99.9%<001 pm
  • Filtration micron rating: down to 0.001 micron
  • Filtration efficiency: up to 99.99%
  • Operating temperature range: from -70 ℃ to 250 ℃
  • Maximum working pressure: up to 21KPa
  • Connection: flange connection
  • Connection size: ASME or DIN 3/4 inch to 8 inch or DN 20-DN 200

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Filson Seal Gas Filter

Your Best Seal Gas Filter Supplier in China

Filson seal gas filter is specially designed to remove liquid and solid contamination and maximize reliable dry gas seal operation. Filson seal gas filtration systems are available in single and duplex configuration by using stainless steel or high grade alloy as a standard material.

In addition to complying with filtration requirements. Filson high-quality seal gas filter can eliminate contaminants down to 0.1 micron or smaller at filtration efficiencies of 99.9%, coalescing performance is down to 0.005 ppm , all within a smaller footprint.

Filson seal gas filters comply with international pressure vessel and design codes. They were designed in ASEM code and EU certification. Beside, we can manufacture replacement seal gas filter of some leading brands like Indufil duplex filter, John Crane Indufil seal gas filter.

If you have any needs for Filson seal gas filter, we are always here to support you satisfied service and awesome product. Send us your inquiry for Filson seal gas filter!

Any other questions? Click Here for more information.

Seal Gas Filters: The Ultimate FAQ Guide

Today’ guide answers all questions you have about seal gas filter.

Whether you want to learn about seal gas, types of filters, working principle, cost, quality testing or any other concept, you will find answers here.

Let’s dive right in:

What is Seal Gas Filter?

A seal gas filter is a device that you will use to remove contaminants from your seal gas.

Seal gas filters are some of the most vital components of the dry seal filtration process.

The continued operation of the seal gas system relies on the provision of clean and quality.

The filters will ensure that the seal gas supplied is free from solid, liquid, and aerosol contaminants that can cause premature seal collapse.

Seal gas filter element

What is Seal Gas?

This gas is also known as a buffer gas.

It is a highly filtered gas that you inject on the space created between the primary and rotating mating faces of the dry gas seal.

The gas will provide a conducive working fluid in the running space.

Also, it will protect the cover from the atmosphere.

Additionally, it protects the process gas inside the centrifuge processor.

You should choose an inert and nonflammable gas as your seal gas.

In some cases, the process gas discharged from the compressor is filtered and pumped back as the seal gas.

But in some cases, nitrogen is used as a buffer gas.

Other inert gases such as argon, helium, or neon can serve as an external source of seal gas.

What is a Dry Gas Seal?

You will use a dry gas seal when you want to create a barrier between the atmospheric gas and the process gas.

It will prevent the contamination of the process gas by atmospheric gas.

Besides, it is also fundamental in preventing the escape of process gas into the atmosphere.

The non-contacting, dry running mechanical seals consist of a stationary primary ring and a rotating mating ring.

When in operation, the grooves found in the mating ring will generate fluid dynamic force.

This force will lift off the primary ring, creating a running gap between the two surfaces.

Onboard of the dry gas seal is a labyrinth seal that separates the process gas and gas seal.

You will inject your sealing gas.

In most cases, a filtered process gas is between the gas seal and the inner labyrinth seal.

On the onboard of a dry seal gas, you will find the barrier seals that separate the compressor shaft bearings and the gas seal.

How does Seal Gas Filter Work?

Gas filtration

The seal gas enters the filter through the inlet port.

In particulate filters, particles are removed from outside to inside direction.

While in coalescence filters, filtration occurs from inside-out direction.

In particulate filters, filtration of most particles occur in contaminants that can’t float in the gas flow.

They hit and stick on the filters through impaction.

Diameter of the sieve restrains the medium size solids that are suspended in the air and follow a turbulent flow through interception.

The diffusion process removes the light particles which follow the Brownian motion principle.

Diffusion occurs when they slow down due to random collisions with gas molecules.

In coalescence filters, you find the fine mesh on the inside and coarse mesh on the outside.

When gas molecules pass through the fine mesh, liquid droplets are blocked and trapped on the mesh.

The fine mesh holds the small droplets long enough to allow the combination with other molecules as the gas continues to flow.

As the droplets increase in size, they move towards the coarse mesh.

This allows them to combine and form more massive drops.

The large drops flow down the side of the elements.

Normally, it is the collection sump, where they can drain automatically or manually using drains valves.

How many Types of Seal Gas Filters are there?

Seal gas filter system

These filters should be installed immediately after the connection point to a seal gas system.

They will provide the last chance of filtration of the seal gas.

Therefore, they should abide by the gas quality requirements and regulations.

The following are the types of filters available for seal gas filtration:

· Demister Filter

You can use this device as a pre-separator when the seal gas is highly contaminated.

They are specifically crucial for removing and reclaiming liquid droplets from a flowing seal gas.

This device achieves effective removal of droplets through the repeated diversion of gas flow through it.

The gas passes through a wire mesh, which removes the droplets through inertia.

The droplets clash with the wire and collect at the crossover of the mesh.

The process results in large drops that flow down the sump through gravity.

Demister filter

They can only achieve a limited degree of separation, and the outflow seal gas will still need to pass through the coalescence filter to remove the finer droplets.

These devices are also susceptible to fluctuations in operating conditions.

· Cyclone Filter

You will use this device as a pre-separator when the seal gas is full of particulate and liquid contaminants.

It removes contaminants through centrifugal force.

The seal gas gets into a fast rotating cyclone through a special introduction.

The centrifugal force will carry the contaminants to the outer wall of the cyclone.

Once separated, the particles redirect to the collection zone through the inner wall of the cyclone.

Cyclone gas filter system

Gas decontamination using a cyclone is always associated with high-pressure loss as a result of very high gas velocity for efficient separation.

Moreover, its efficiency highly relies on the operation conditions.

· Particulate Filters/Strainers

You will use this filter to remove solid contaminants from the seal gas.

The efficiency of the filters will depend on the mesh sizes.

Particulate filters remove different sizes of particles using different procedures and processes.

They will remove large solid particles through impaction.

Here, the particles cannot float on the seal gas and therefore collide and stick on the filters.

The filters remove the medium size particles through interception.

This occurs through restraining because they cannot go through a sieve mesh with narrow openings.

The smallest particles are filtered out through diffusion.

This process relies on random movement and collision of particles.

Eventually, the particles slow down and stick on filters medium.

HEPA Particulate Filter

· Coalescence Filters

These filters remove liquid from the seal gas.

You should use these filters in all your seal gas applications.

This is because the dry seal gas must be free from a liquid at all times to avoid damage and possible leakage of the process gas.

These filters are specifically crucial in removing very fine liquid aerosols that cannot be removed by gravity drainage, physical barriers, and other pre-filters.

Coalescing filter

Here, the seal gas will pass through the filter element.

It will capture and retain the small liquid droplets for an extended period.

This will allow for coalescence with other liquid particles to form bigger particles.

The large particles will be released on the exit end of the filter element and drained into the sump for by gravity force.

This filter should be able to filter out particles of at least 3 microns and above to achieve a standard quality seal gas cleanliness.

Why should you Filter Seal Gas?

You should always ensure that your seal gas is very clean.

In most cases, it is advisable to use filters that can remove particles that are 3 microns and above.

Furthermore, your filtration system should be able to remove up to 99.97% of the liquid in the seal gas before injecting it into the application.

When you inject a contaminated seal gas into the system application, the contaminants will block the grooves of the seal.

Remember, this is necessary for the creation of the running gap.

It will result in face contact leading to damage of seal faces, which can lead to contamination and loss of process gas.

How does the Seal Gas Filtration System Work?

Gas filtration process

The seal gas filtration system’s primary function is to provide a clean and dry seal gas to the compressors’ seal system.

Usually, the source should be able to provide a seal gas with enough pressure for the entire system.

If you are using compressor discharge gas as your source, then you can use a booster to increase the pressure.

The seal gas is passed through a pre-filter, which is either a cyclone or demister.

These are situations where the seal gas is highly contaminated.

The gas then proceeds to a particulate filter for removal of solid particles then coalescence filter for removal of water and moisture particles.

Some filters have merged particulate and coalescence filters.

The filters should remove particles that are 3 microns and above, achieving at least 99.9% particle removal efficiency.

The clean gas moves into the dry gas seal.

This seal has a rotating mating ring and a stationary primary ring.

When the mating ring rotates, the grooves in the mating ring create a dynamic pressure, which forms a running gap between the two faces.

This running gap receives the clean seal gas, which acts as a barrier between the atmospheric gas/air and the process gas.

A separation gas, usually inert one, is supplied to prevent contamination of the dry gas seals from lubricants applied to the compressors running joints.

What are the Components of the Seal Gas Filter?

The main components include:

· Housing

Gas filter housing

There are two types of housing, the simplex, and the duplex housings.

The housing hosts all the components of the filter.

The design and size of the house will depend on the requirement of your operation.

Ensure that the housing is compatible with the piping system and the filter elements before you place a purchase order.

· Filter Elements

Air filter element

These devices have the filter medium and perform the actual filtering of the seal gas.

Some manufacturers provide filters that have both particulate and coalesce filters.

· Sump

It is in the lower section of the filter housing.

They allow for the collection of liquids originating from the filtration process.

· Drains

These can either be automatic or manual.

If you are using manual drains, then you will have to check and drain the accumulated liquids from each filter daily.

Ensure that you maintain minimal liquid accumulation normal operations on the filter to achieve higher quality seal gas filtration.

· Valve

They mainly include:

· Differential Pressure Gauge

This device will let you know when you need to change the filter elements.

You should have a pressure gauge on the upstream of the filter assembly to record the supply pressure of the seal gas.

Through the pressure gauge, you will know when to consider filter replacement.

· Inlet and Outlet Valves

This will allow you to pump the seal gas in to and out of the filter.

The location of these will depend on the design of the individual filters.

What will Determine the Choice of Seal Gas Filter?

The following factors will determine the choice of seal gas filters:

i. Operation Conditions

You should ensure that you select a filter that can withstand maximum temperature and pressure for your operating environment.

If you choose a filter with a lower working pressure and temperature, then your filtration system is going to be disintegrated

ii. Filtration Requirements

This type of filtration will determine what kind of filter you purchase.

For example, particulate filters will have housings with different designs and configurations compared to coalescence and bypass adsorbent filters.

iii. Type of Contaminants to you want to Remove

Every filter will remove particular type of pollutants.

Contamination levels of your seal gas will influence this.

If it is having a lot of solid particle and liquid, then you will install a pre-filter, particulate and a high quality coalescing filter

iv. Physical and Chemical characteristics of the Seal Gas

The properties of the seal and process gas will determine the filter element material.

If you are working with corrosive gasses, then you must choose materials that are resistant to corrosion.

v. The Level of Filtration Required

Different models of filters have different abilities, ratings, and grades.

For example, a filter can be a coalescence filter but with varying capacities of filtration.

Many seal gas suppliers recommend that the filter should be able to filter particles that are 3 microns and above.

However, some filters can achieve up to 1-micron filtration.

vi. Sizing of the Filter

You must consider the size of the filter.

Small filters are cheap, have a fast response rate, and require little space for installation.

On the contrary, a large filter has a longer service interval and a lower pressure drop.

What are the Quality Standards for Seal Gas Filter?

A high-quality seal gas filter is mandatory for a smooth and continued operation of the seal filtrations system.

ISO 12500 gives directions on quality standards for manufacturing and testing of seal gas filters.

These standards regulate the testing of filters for compressed air systems.

You should know what characteristics you require for your seal gas to select a proper seal gas filter.

At the moment, many manufacturers demand that a seal gas filter should be able to remove particles that measure 3 microns with 99.9% removal efficiency.

You should also know that different countries have their regulations, laws, and directives outlined in various codes.

For example, Codes TR CU 010 (EAC), TR CU 012 (EAC), and TR CU 032 (EAC) contain specifications used by Belarus, Kazakhstan, and Russia for quality control.

Canada has CRN and China has TSG 21-2016.

Internationally, other relevant code includes the ISO 10438-1.

It gives directive on the quality standards associated with petroleum, petrochemical, and natural gas industries.

What are the Properties of Good Seal Gas?

You should ensure that your seal gas meets the following requirements.

  • Be an inert gas
  • Not toxic to human health or potential environmental hazard
  • It process should be able to tolerate it contaminating the process gas
  • Be clean and dry
  • It should withstand a wide variation of temperature and pressure

Is Buffer Gas the same as Seal Gas?


Seal gas and buffer gas are interchangeable as they refer to the same gas.

How long can Seal Gas Filter Last?

The service life of a seal gas filter will depend on the level of seal gas contamination.

You should have a differential pressure indicator to alert you when your filters require replacement.

Generally, a big filter housing and cartridges will also translate to an extended filter shelf life.

Other materials like microfibers also have higher dirt holding capacity and will, therefore, have a longer service life.

You can choose to use disposable filters or cleanable filters.

How do you Install and Maintain Seal Gas Filter?

You should ensure that you conduct a routine inspection and maintenance servicing of the filters’ housing and elements.

Ensure that you select the most appropriate material for your filters.

Check for signs of wear and tear or corrosion on the housing.

In case of any visible indicators, immediately replace the housing to avoid any leakage and bypass.

Use disposable microfiber elements for polishing filtration of endpoint use only.

They have to be protected by a pre-filter since they cannot perform continuous bulk filtration.

You should also routinely test the quality of seal gas.

You can use a compatible pipe sealant while fitting the filter house on the port.

It will ease disassembling at a later period.

Fit the filter elements according to the arrows indicated on the filter.

Take care so that you keep the head and housing as pair.

How do you Replace your Seal Gas Filter Elements?

Follow the following steps and instructions when changing your filter elements:

  • Release the line and housing pressure and remove the bowl, filter element, and retainer.
  • Drain any liquid in the housing and clean it using soapy water and a clean cloth.
  • When fixing the stainless steel, insert gaskets at both ends of the filter before placement in the housing.
  • If indicated, seal the elements by tightening the thread element retainer on the housing.
  • Check for any damages on the sealing surface and mating thread. Clean the sealing surfaces and the thread then lubricate them using silicone grease.
  • Tighten back the bowl firmly but don’t overtighten.
  • Before resuming operations, ensure that all connection ports, housing, elements, drain plugs have been correctly installed

How much does Seal Gas Cost?

The cost of a seal gas varies depending on the type of filters, size, material, working pressure, temperature, flow rate, among other things.

For example, you can pay as little as $3 for a PTFT replacement filter element.

While a replacement stainless steel filter element can cost you up to $ 280.

Ensure that you check and confirm the prices for the filter model you need before placing an order.

How can you Test the Effectiveness of Seal Gas Filter?

You can test the effectiveness of your seal gas filter using guidelines provided for under ISO 12500 standards.

For testing the removal of aerosol oils by coalescing filters, you will follow the guidelines of ISO12500-1.

For vapor filtration by adsorbent filters, you can refer to procedures under ISO 12500-2.

For removing solid particulates, you can use procedures under ISO 12500 part three.

How do Simplex and Duplex Seal Gas Filters compare?

Simplex gas filter

Duplex gas filter

Duplex seal gas filters have two identical seal filter housings connected with a transfer valve.

They allow for easy and quick changeover from the operating to the standby filters in case of servicing, maintenance, or breakage without interruption the gas flow.

Simplex seal gas filters, on the other hand, only have a single filter housing, and the gas flow has to completely stopped in case of operation and maintenance.

What Material can you use to Make Seal Gas Filter?

The seal gas systems operate under very harsh working conditions such as refining and oil extractions, oil explorations, chemical processing, and petrochemical industries

You must choose seal gas filters with a material that can withstand a harsh operation condition.

· Housing

You can have the housing made from several materials.

Filters made from exotic and standard materials are available to ensure that the products can accommodate even the harshest of conditions.

Some of the common materials include carbon steel, stainless steel, aluminum, SS 304, SS 316L steel, nylon, and some high-end exotic materials.

· Filter Elements

Similarly, you will select the filter elements depending on your application and operation conditions.

Several materials are available for making seal gas filter elements.

They include:

· Borosilicate Glass Microfiber

These materials are suitable for making coalescence filters with very high efficiency.

It consists of boron and silica.

The fibers are treated and made into a very tight labyrinth with a large free area.

The open regions make aerosols particles continuously change direction, which leads to a reduction in speed and filtration.

You can have a finer layer of this fiber on the inside with a coarse layer on the outside.

These two layers enable the thread to filter the gas from the inside out.

The fine layers will trap the aerosols and form droplets.

However, the growth of the droplets in the fine layer is usually restricted.

Once the droplets get to the outer course layer, they will form large visible drops where they run down the sides of the element into the sump.

Because of the numerous free spaces, the elements can hold the most amount of dirt.

· Pleated Cellulose

You can use pleated cellulose to make the inner layers of pre-filters.

A course matrix of glass fiber will form the outer layer.

The coalescence filter will perform bulk filtration where low-pressure drop and high efficiency is required.

You can use this filter when you want elements with a high capacity to hold dirt and filter finer particles as well.

· PTFE Filter Elements

These elements are also known as Teflon filter elements.

You can construct them by pure sintering granules of PTFE without mixing with another substance.

You can use this filter when your application system demands plastic filters.

They are characteristically well suited because they offer a wide range of chemical resistance and can withstand up to 200°C.

Even though you can clean them ultrasonically, using disposable type K PTFE filters will give you better performance and are economically friendlier.

· Stainless Steel Filters

Stainless steel elements can filter a very heavy contaminated gas.

Because of the material durability, you can always reuse it when cleaned through ultrasound or back flashing.

You can select the most suitable filter element depending on your contaminants.

There are different products than can filter particles as small as 0.5 microns and up to 200 microns.

· Sintered Polyethylene (PEL) Sintered Polyethylene Elements

This filter consists of a virgin polyethylene (H.D.P.E.).

Once you crash the material into powders and granules, compress it into a sintered tube.

The process frees the elements from foreign binders.

Only polyethylene can raise any compatibility concerns.

The filters are naturally hydrophobic.

They can act as coarse particulate pre-filter or pre-coalesce filters in seal gas filtration.

They are relatively cheap and economical to use and dispose of even though they are cleanable.

Are Seal Gas Filters Reusable?

Yes, seal gas filter elements can be cleaned and reused.

However, some filter elements are for one-time use only.

An attempt to clean them will destroy the filter elements.

In most cases, the manufacturers will provide directions on how to clean the filters.

There are two main methods you can use to clean the filter.

They include:

· Ultrasonic Cleaning

You will use an ultrasonic cleaning machine to remove dirt from the filter elements.

In principle, this transmits sound wave that produces a cleaning effect on the filter element.

The filter has to submerge in water inside an ultrasonic tank completely.

Transducers introduce ultrasonic energy into the water.

The energy causes vibration of the tank as it produces sound waves within the container.

Rapid oscillation of the sound waves results in microscopic implosions that are responsible for the effective cleaning of the filters.

These waves will have a cleaning effect on every part of the element submerged underwater.

The process will efficiently get rid of all the dirt in the filter medium.

· Backflushing

When conducting backflushing, you apply water from the inside out.

The water pressure is usually very high to force out particles inside the pores.

Since the pressure is very high, you will use the shortest time possible to achieve effective cleaning of the element pores.

How does Seal Gas Filters compare to Process Gas Filters?

In most cases, seal gas filters have a higher capacity and filtration efficiency than other standard gas filters.

It is because the cleanliness standards of the seal gas are usually higher.

Most seal gas filters should have a filtration capacity that is 2 to 5 times higher.

The diameter of the filter elements should be 3 to 4 times narrower than standards gas filters.

Similarly, differential pressure indicators usually have a higher alarm to signal for element replacement.

Do Seal Gas Filter have a Warranty?

Yes, many manufactures offer limited warrant cover for their goods.

Although most provide a cover for upto one year from the date of shipment, some manufacturers may offer less or more.

Depending on the nature of the warranty, the manufacture may decide to repair, replace, or refund for any defective goods.

However, most warranty covers are limited and will not cover your goods in case of neglect, misuse, abuse, poor installation, and poor handling.

The warranty may also not cover goods that have been altered, repaired, reconstructed, or used by other third-party hardware or products.

Ensure to confirm with the manufacturer the nature and period of the warranty they will offer for their goods.

Choosing a suitable seal gas filter requires an in-depth understanding of every concept highlighted in this guide.

However, if you have any question on seal gas filtration systems, contact FilSon Filters team.

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