How does a coalescing filter work?

Posted on Nov 20, 2019 by Tiffanie Gupton

passive dehydration oil and gas

What is a coalescing filter?  

Coalescing filtration or Coalescing gas separators are designed specifically for the removal of mist, fogs, and dust from gas streams. These contaminants usually exist with the bulk of the particles having diameters considerably less than 10 microns; therefore, standard separators or scrubbers are not capable of effectively removing these minute particles. You can read more about what a coalescing filter is from our previous blog. 

How do they work?  

Gas containing entrained liquid, mist, fog, dust, rust or scale enters the vessel through the inlet connection into the large inlet chamber ahead of the coalescing elements. This allows the gas to distribute around the coalescing elements for efficient use of the available filter surface area. Solid particulate materials are trapped by the filter element fibers as the gas and liquids pass through. The liquid, mist or fog is retained by the fibers of the filter element until enough liquid accumulates to form a large drop. The gas then forces the large drops through the filter element. These large drops are then separated from the gas by gravity or by the action of the mist extractor section.

The liquid accumulates in the liquid chamber where it is removed by the action of the liquid level controller and dump valve. The liquid accumulation may have a specially constructed wire screen divider which prevents liquid from being re-entrained into the gas stream. The gas, free from its particulate contaminants and liquids, leaves the vessel through the gas outlet.

Gas containing entrained liquid, mist, fog, dust, rust, scale enters the vessel through the inlet connection near the top of the vessel. The gas is deflected around the shell of the large inlet chamber by a deflector plate so that the gas stream does not impinge upon the coalescing elements. This allows the gas to distribute around the coalescing elements for efficient use of the available filter surface area. Solid particulate materials are trapped by the filter element fibers as the gas and liquids pass through. The liquid mist or fog is retained by the fibers of the filter element until enough liquid accumulates to form a large drop. The gas then forces the large drops through the filter element. These large drops are then separated from the gas by gravity or by the action of the mist extractor section.

The liquid accumulates upon the center diaphragm plate immediately above the gas outlet and then flows through the center downcomer into the lower liquid accumulation section where it is removed by the action of the liquid level controller and dump valve. The gas also flows through the center downcomer into the liquid accumulation section, where it reverses direction and passes through the wire mesh mist extractor. The gas, free from its particulates, contaminates and liquids, leaves the vessel through the gas outlet in the center of the vessel. Liquid accumulating in the coalescing element chamber is removed by the action of the liquid level controller and dump valve.

In our previous blog, What is a Coalescing Filter? we explained what it is and its functions. Below is the picture to show the process.

CF Process Picture - Single

Coalescing filters can be equipped with standard accessories. These can be used for both vertical and horizontal filters. Many of these accessories can be purchased at CroftSupply.com.

Coalescing filters

Need to buy parts for a coalescing gas separator click here.

If you have any used coalescing gas separator for sale click here.

Need to buy used coalescing gas separator click here.

Need to buy a new manufactured coalescing gas separator click here.

Tiffanie Gupton

Do NOT follow this link or you will be banned from the site!
Scroll to Top