Coalescing Filter Housing: The Ultimate FAQ Guide

I know you’re looking for high quality coalescing filter housing.

Or, you would like to learn more about coalescing filter housing.

Today’s guide covers everything you would like to learn about coalescing filter housing such as functions, designs, and quality standards, amongst others.

Keep reading.

What is a Coalescing Filter Housing?

This is a pressure vessel which holds the coalescing filter elements and other integral parts such as the ports, drains, etc.

Usually, the housing comprises of the head and the bowl but can include more components.

Coalescer filter housing

 Coalescer filter housing

What are the Functions of Coalescing Filter Housing?

The main function of the housing is to ensure that the filtration process is smooth and efficient through holding the coalescing filtration elements in place.

What are the Components of Coalescing Filter Housing?

The coalesce filter housing comprise of the following components:

Coalescer filter housing

 Coalescing filter system

Inlet and outlet ports Allow the process fluid into and out of the filter assembly.

O-rings: These rings help prevent leakage from the housing.

Differential pressure gauge: It measures the pressure drop across the filter element and alerts you when the elements are due for replacement.

Bawl: This is where you place the coalescing cartridge. The bawl should be big enough to hold the required number of cartridges and space for coalesced water collection.

Head: It closes the bowl after the installation of the filter elements. It contains the pressure relief valve,: checks valves, and air eliminator valve.

Vent/air eliminator: It allows air that is trapped in the housing vessel to escape upon filling with the process fluid. It will close automatically after all the air has escaped.

Check valve: It helps avoid air ingression into the housing vessel after the air has been eliminated.

Pressure relieve valves: This helps the system eliminate excess pressure that has built up in the system. It has an automatic sensor that detects if the levels are beyond the preset levels and signals for automatic release.

Sample ports: They are located right at the incoming and outgoing process fluid ports. You will use them to draw an inlet and outlet samples for quality tests.

Sump: The sump is located at the bottom part of the housing bowl. It holds the coalesced water and large solid particles.

Drains: It is located in the lower parts of the housing.

You use drains to remove the contents of the sump.

They are also helpful when you want to collect fluid samples in the filter and access the condition of the coalescing element.

Stand/Mounting holes: The stand offers support to a large housing assembly while the mounting holes help fix the housing in a pipeline.

You can also use it to remove the process fluid in the filter when replacing elements.

The drain can be manual or automatic.

What are the Characteristics of a Good Coalescing Filter Housing?

A good coalescing filter housing should:

  • Meet the quality standards provided by the regulatory authorities. Such standards include ASMA, PED, etc
  • It should have a large filtration space
  • The housing should have curved corners. This helps in reducing breakage from high pressure and facilitates easy cleaning.
  • It should subject a very low-pressure loss to the process fluid
  • Possess very high filtration precision
  • The separation effects should be good
  • Must be compatible with the requirements of your process application
  • The material of construction must be compatible with the chemical characteristics of the process fluid and contaminants
  • Should withstand the process flow rates, operating pressure, and temperature
  • Should be easy to open and clean for fast replacement of elements
  • Should have a nicely done surface furnishing
  • The internal surface must be free from cracks and crevices that can hold dirt.

What are the Best Materials for Constructing a Coalescing Filter Housing?

You can construct a coalescer filter housing using several materials.

However, the choice of materials will highly depend on the requirements of your process application.

The following are some of the commonly used materials for construction of coalescing filter housing:

Coalescing filter element and housing

Coalescing filter element and housing

1) Carbon Steel

This material is a combination of carbon and iron alloys although it can also contain some amounts of metal alloys such as silicon, copper, and manganese.

The strength of carbon steel will depend on the amount of carbon added to steel during manufacturing.

The grades of carbon steel include:

· Low or Mild Carbon Steel

This material constitutes between 0.05 and 0.3% carbon content.

It is widely used for constructing filter housing which operates under less stringent conditions.

This type of carbon steel will make filter housing which is lower priced given that it is cheaper.

Although it has low tensile strength, it is easy to work with.

You can also increase its surface hardness through carburizing.

· Medium Strength Carbon Steel

The carbon content in this material range from 0.25 to 0.60%.

The percentage of manganese can vary between 0.6 to 1.65%.

It has more hardiness than low strength carbon steel which also makes it harder to work with.

You can also improve the mechanical hardiness of the materials through heating while adding alloying metals such as chromium, nickel, or molybdenum.

· High Carbon Steel

It has a carbon content varying between 0.6 to 1.7% and manganese content ranging from 03 to 0.9%.

The resulting material is usually very hard with very high resistance to wear and tear.

You can add different quantities of an alloying element to improve the hardiness of the materials.

Carbon steel is less likely to break or crack under high pressure compared to other types of steel.

However, carbon steel is more susceptible to rust and corrosion compared to stainless steel hence not suitable for sanitary applications.

2)  Stainless Steel

Stainless steel is one of the best materials for constructing a coalescing filter housing.

The material is manufactured by combining low quantities of carbon, ranging from 0.03 to 1% with iron.

However, the resistance to corrosion is achieved by adding at least 11% chromium.

There are different grades of stainless steel depending on the quantities of alloys added to enhance its resistance to corrosion.

They include 200, 300, and 400 series depending on the metal alloys.

Stainless steel grade 300 series are the best for making filter housing because they have the highest resistance to corrosion.

The most common are:

· Stainless Steel (SS) 304

This grade of stainless steel comprises of 18% chromium and 8% nickel. Nickel significantly improves the ductility of the material.

The material also has small amounts of manganese, carbon, silicon, and traces of molybdenum.

Though this material is not as resistant as SS 316, you can steel use it in applications with little corrosive agents.

The main advantage of SS 304 is that it has excellent formability and is cheaper compared to SS 316.

· Stainless Steel 316

This grade of stainless steel comprises chromium, nickel, and molybdenum at 16, 10, and 2-3%, respectively.

The high quantities of molybdenum tremendously increase its resistance to pitting corrosion.

You can select this material for constructing filter housings which deal with highly corrosive material or where the housing is constantly exposed to water.

It is also stronger and more expensive compared to SS 304

3) PTFT Housing

You can construct the housing using a high quality solid plastic PTFT bar which has high chemical resistance.

They have stainless steel support disc on the outside to increase strength between the bowl and head connection.

The material is hydrophobic and suitable for constructing membrane housings for coalescing filters that remove water from a gas stream.

The membrane repels the water allowing only the gas to pass.

They are also suitable for filtering water from a hydrocarbon-based liquid such as diesel.

You can use PTFT filter elements together with these types of housings to achieve 100% PTFT filtration solutions.

4) Plastic Housing

You can construct plastic filter housing using PTFT, nylon, polypropylene, and PVDF.

The plastic filters are suitable for use in applications that operative under high corrosive environments with low operation pressure and flow rates.

They are ideal for applications that require lightweight, non-corrosive materials.

Housings constructed from polyethylene and polypropylene are usually cheaper compared to PVDF which can operate at a relatively higher temperature.

· Aluminium Housing

You can use aluminium filter housing in a wide range of applications, thanks to its lightweight and gullibility.

However, aluminium is less durable and weaker compared to steel and carbon steel.

It is also susceptible to corrosion by chemicals.

What Designs of Coalescing Filter Housing are there?

There are two main designs of coalescing filter housing’ that is horizontal and vertical.

Both designs can be modelled to use single or multiple cartridges.

The vertical design is suitable in applications where the installation space is limited because it needs a small floor area.

Vertical coalescing filter housing

 Vertical coalescing filter housing

The horizontal coalescer filter needs a large floor area but also provides a bigger filtration space and allows for a higher flow rate compared to vertical housing.

 Horozontal coalescing filter housing

 Horizontal coalescing filter housing

When installed in-line, a horizontal filter housing will offer a lower pressure drop compared to a vertical housing.

How do you Select Coalescing Filter Housing?

Selection of the most appropriate filter housing depends on several factors which include:

· Porting options

The location and size of the housing port are very critical when selecting the design.

Ensure that the design and model of the housing you select is compatible with your piping system.

You have to match the size of the housing port to that of the piping system.

· Mounting Process

The installation of the filter housing in your system will significantly impact the effectiveness and cost of the overall filtration system.

When your system requires different fluid cleanliness standards, then installing smaller filters at the point of use will offer more effective filtration than central installation.

Ensure that you appropriately install the filter in a visible location along the system pipeline.

So that the maintenance personnel does not overlook it. Label the filter appropriately.

Take consideration of the pressure drop which arise from the use of a filter housing when sizing the filtration system.

· Drainage Option

Coalescing filter housing can either drain automatically or manually.

Depending on the requirements and available manpower, you can select either.

The main advantage of the automatic drainage is that you will not need personnel to drain it daily unlike a manual filter.

· Pressure Rating

Unlike the above factors which depend on the housing design, the pressure rating is determined by the application process requirements.

The choice of a filter’s pressure rating will depend on where you intend to install the filter within the system.

Ensure that the filter housing you select can withstand the pressure spikes as well as the normal pressure under normal operating conditions.

· Operating Temperature

Similarly, the operating temperature will depend on the characteristic of your system.

Ensure that the filter housing you select can withstand the system temperature or otherwise it will deform and result in poor fluid filtration or leakage.

You also need to ensure that the housing can withstand the system temperature spikes, both on the lower and upper limits, without risking the quality of filtration.

· Flow Rate

It is prudent that the housing you select is compatible with the system flow rate.

A housing with a lower flow rate will significantly reduce the system fluid velocity due to out of range pressure drop.

Similarly, having a housing whose flow rate is higher than that of your system will significantly affect the quality of your fluid

· Design Configuration and Size

You can use either vertical or horizontal filter housing for your application.

However, the special filtration requirements of your process may demand a particular design.

When selecting a design, ensure that you factor in the system configuration and the available installation floor area.

Also, ensure that the design you are selecting is having the right size to host all the number of cartridges necessary to achieve the desired filtration levels.

Research also shows that filter housings with more space for filtration give better filtration performance.

· Material of Construction

The material for constructing a coalescing filter housing depends on different factors.

When selecting the material, it is vital to confirm that its properties are compatible with the chemical properties of your process fluid and contaminants.

The material should be durable, strong, and easy to clean.

Some applications require specific materials which should meet special needs like cleanliness or temperature tolerance.

· Cost

The cost of owning the filter housing should not exceed your budget.

Include the cost of purchase, installation, special inclusions, and maintenance.

What is the difference between a Duplex and a Simplex Coalescing Filter Housing?

 Simplex coalescer housing

Simplex coalescer filter

The main difference between these housing models lies in their operation.

You can only use simplex coalescing filters in batch applications which you can stop and replace the filter elements.

Simplex housings should be easy to open and clean to reduce downtime for element replacement.

On the other hand, you will need a duplex coalescing filter housing when working with continuous filtration processes which you cannot stop.

The duplex housing comprises of a pair of simplex housing that joins together through a three-way valve.

When the filter element in one housing is filled, you can divert the operations to the other housing using the valve without shutting down the operation.

Once switched, you can then remove the elements and replace them with clean cartridges in a similar manner to the simplex element.

What are the Advantages of Duplex Coalescing Filter Housing?

Duplex coalescing housing

Duplex coalescing housing

Duplex coalescing filter housing has numerous advantages. Some of the most outstanding advantages include:

  • Longer service life because of the high dirt holding capacity
  • Maximum system operation and output production due to Zero downtime
  • Uninterrupted operations
  • Faster and easy access and replacement of the filter elements thanks to conducive bolting methods
  • Ease of handling and operating.
  • Enhanced filtration results due to availability of large filtration space
  • Flexibility in use. You can easily change operation from one application to the other without new equipment.
  • Meets all the international quality standards for a wide range of application
  • Compatible with a wide range of filtration media of different materials.

How can you Test the Quality of a Coalescing Filter Housing?

You can perform pressure-proof and leakage tests to confirm the ability of a filter to withstand pressure and free from gas leakage.

· Proof and burst test

You will conduct this test to confirm the operating pressure of the housing.

For validation, you should hydraulic oil and 1.5 times higher pressure to the indicated allowable pressure for 15 minutes or more.

· Helium leak test

You can use this test to check for any gas leakage across the seals and welded joints.

Submerge the housing in the water while applying the desired amount of pressure on helium gas for one minute.

Increase the pressure at 25%, 50%, 75%, and 100% of the operating pressure while checking the seals for any leakage.

· Flow test

The test measures the amount of pressure drop conferred by the housing.

You can use water for liquid coalescers or helium for gas/air coalescers filters.

Measure the differential pressure at the inlet and outlet of the filter then work out the difference.

What Determines the Size of a Coalescing Filter Housing?

The performance of a coalescing filter is proportional to the size of the filter.

Some of the factors which are critical when sizing the filter housing include:

  • The flow rate of your system
  • The quantity and characteristics of the contaminants
  • The filter replacement frequency
  • Filtration efficiency

Are there any Quality Standards for Coalescing Filter Housing?

Generally, designing, construction, and use of coalescing filter housing should comply with requirements of the following standards:

  • Pressure Equipment Directive 2014/68/EU
  • ASME Code Section VIII and
  • ISO 9001:2015

However, individual industries and application may have special standards which must be met with the coalescing filter housing.

Why Choose Stainless Steel Coalescing Filter Housing?

As mentioned earlier, stainless steel is one of the best and widely used materials for the construction of coalescing filter housing.

Though there are other good materials, you should use stainless steel for the following reasons:

  • It can withstand high system pressure and flow rate
  • It can withstand a relatively wide temperature, ranging for -22°C to above 250°C without any deformities
  • It can withstand corrosion over a wide range of agents.
  • It has high aesthetic properties.
  • It is easy to clean

What Factors will Influence the Price of a Coalescing Filter Housing?

The price of coalescing filter housing depends on:

  • The material of construction
  • The size of the housing
  • The process application
  • The design and model
  • The pressure and flow rate ratings

How can you Clean a Coalescing Filter Housing?

Coalescing filter ousing

Coalescing filter housing

· Automatic Cleaning

Auto backwash filters operate from outside to inside cleaning where unfiltered fluids get into the filter from the lower region.

Also, the particulate contaminants stick on the outside of the cartridge, and the clean fluid pass through the inside part and exit through the top.

Besides, the differential pressure signals for the automatic shutdown of the inlet and outlet ports once the preset pressure drop has reached.

Furthermore, the backwash valve and drain open for some time and wash down the particles sticking on the surface of the cartridge.

The washing interval is set as per the requirements of the process application.

To enhance uninterrupted operation, these filters have multiple elements.

This allows the operation of one of the elements when the others are being washed to facilitate uninterrupted operation.

· Manual Cleaning

For applications such as water filtration, you can use warm soapy water and a brush to scrub off dirt from both the interior and exterior surfaces of a filter housing.

Rinse of the surfaces using clean water then prepares a solution of bleach by adding one-third of unscented household bleach to 1 gallon of clean water.

The suspension is a sanitizer that disinfects the filter housing and piping.

Add a single cup full of the solution to the sump of each filter housing then connect the housing back to the piping without the cartridge.

Let the water flow through the cutoff valves to fill the housing then close the faucets as soon as the water starts flowing out.

Let the water settle and contact all the parts of the lines, housing, and faucets for at least 30 minutes before removing the housing and discarding the sanitizer.

Replace the cartridges, fix the housing into the piping then check for leakage.

Other applications like fuel coalescing filters recommend the use of clean fuel instead of soapy water to clean the filter housing.

How do you Install a Coalescing Filter Housing?

Proper installation of a filter vessel will have an impact on the effectiveness and overall cost of filtration in the long run.

  • Identify the inlet and outlet by the markings on the housing. Proper installation is mandatory for appropriate filtration.
  • Align the piping appropriately to avoid pressing on the vessel. You can include shutoff valves on both sides of the filter to enable you only to drain the contents of the vessel during cartridge replacement.
  • Choose sable support or base and bolt the vessel
  • Install the correct sizes of vessels on the inlet and outlet ports before connecting to the piping
  • Install all the required accessories and cartridges as illustrated on the filter manual.
  • Ensure that the seals and cover gaskets are properly aligned and close.
  • Open the shut-off valves to let the fluid flow into the vessel. Check the differential pressure reading and confirm if it is tandem with specifications on the manual.

How do you Maintain a Coalescing Filter Housing?

The lifespan and performance of a coalescing filter housing greatly depend on the maintenance services you perform on the filter housing.

For proper operations, you can follow these tips:

  • Ensure that the internal surface is free of cracks and crevices which can hold any dirt
  • Check for any welded joints for leakages. Also, inspect the gaskets and O-rings to ensure that they are airtight. Replace leaking housing immediately.
  • When loosening or tightening the filter, take not to damage the threads. Always apply a lubricant on the thread and gasket before tightening.
  • Clean the filter housing using a brush and an appropriate detergent if applicable. Depending on your process application, you can select different detergents or even use a clean process fluid, like in the case of fuel coalescing filters.
  • When opening the hosing for filter maintenance, ensure that you shut down all the systems and release the pressure and fluid inside housing before you open. Follow the appropriate guidelines in case you are dealing with toxic gas.
  • After servicing, ensure that you close all the drains before reopening the system.

 What is the Pressure Equipment Directive for Coalescing Filter Housing?

These are guidelines specify how to design, construct, and test the pressure equipment which exceeds 0.5 bars of maximum allowable pressure.

The guidelines address 21 themes on different aspects and include an annex and appendices.

These guidelines aim to ensure the free flow of safe commodities.

The guidelines are not legally binding.

Coalescerf filter system

 Coalescer filter system

What is the Best Surface Finishing for Coalescing Filter Housing?

There are several metal furnishing technologies that you can choose to use for polishing the surface of the metals used to construct a coalescing filter housing.

Some of the most suitable technologies include:

· Electropolishing:

Electropolishing is the reverse of electroplating and revives the valleys and surface roughness in metal pieces through an electrochemical process.

This process also removes embedded contaminants, pits, micro-cracks, burrs, oxide scales, and other imperfections through stripping of a thin and uniform layer of the surface layer.

You can use this furnishing method on all types of steel.

It has about 30 times better resistance to corrosion compared to passivation.

The polished parts have an appealing and lasting bright appearance.

· Passivation

This method removes free iron and other ferrous impurities from the surface of steel using nitric or citric acid.

The process leaves a protective oxide layer that is very resistant to corrosion.

However, you cannot use this method for grades of stainless steel which have low levels of nickel and chromium.

Also, you cannot use to furnish surfaces that have been subjected to welding or brazing as well.

· Pickling

This is the removal of the low chromium content layer and high-temperature scale from the surface of a metal using a mixture of nitric and hydrofluoric acids.

The chemicals also remove ferric acid oxide and ferrous contaminants.

The removal of the low chromium layer enhances the resistance of the metal to corrosion

· Electroplating

The process uses electric currents to deposit another type of metal onto the surface of a substrate metal.

It increases resistance to corrosion, wear and tear, and aesthetic appeal of the metal.

How long can a Coalescing Filter Housing last?

The service life of a coalescing filter housing varies greatly depending on the material of construction and the application provided it does not get physically damaged.

Most plastic coalescing water filter housings can take up to 10 years before the need for replacement.

Coalescing filter housing constructed using metal can take longer or even last the lifetime of the application.

In short, before choosing coalescing filter housing consider everything in this guide.

With this information, you will definitely get a suitable coalescing filter for your applications.

Contact us today for custom coalescing filter housing.

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