To prolong the life of your industrial fluid processing equipment, you must install filters. Filters remove unwanted particles and contaminants from the process fluid before it is allowed to proceed into other machinery.
But what happens when your filters become so dirty themselves, that they can no longer do their job? At that point, you should hire cleaning professionals to clean your filters so you can keep using them without needing to replace them outright.
What does the filter cleaning process look like? In this article, we’ll explain the types of filter cleaning processes that a professional cleaning service like ours, Precision Fabricating & Cleaning (PFC), typically uses, the benefits of filter cleaning, and the types of filter elements that are able to undergo a cleaning process.
Over time, filters get dirty due to the very nature of their function.
A filter’s function is to remove particulates up to a certain size from a process media. The media could be liquid or a gas.
The ability of a filter to remove contaminants is indicated by its micron rating. A micron is a unit of measure in the metric system equal to 1 millionth of a meter in length (about 39 millionths of an inch). The average cross-section of a human hair is 88 microns.
There are two types of micron ratings.
This rating indicates the ability of the filter to capture particles of a specified size at an efficiency between 50 percent and 98.6 percent. For instance, a filter with a nominal rating of 50 percent at 10 micron means that the filter is able to capture 50 percent of contaminants that measure 10 microns in size.
This rating tells us that the filter is capable of removing at least 98.7% of a specific size particle. This rating is determined through a single pass or multi-pass test in which fluid containing measurable particles is passed through a flat sheet of filter material. The particles that pass through the filter are measured and counted. This rating is more informative than the nominal micron rating.
All this tells us that filters trap large amounts of contaminants. These contaminants build up over time and need to be manually removed through a cleaning process. Otherwise, the efficiency and even the functionality of the filter will become compromised.
At PFC, we perform four types of filter cleaning.
For the ultrasonic method of filter cleaning, we first immerse the filter in a process solution. Next, we hit them with high-frequency sound waves (ultrasound), which agitate the solution and cause cavitation bubbles to form. These bubbles eventually implode, causing the contaminants and debris on the surface of the filter to dislodge.
If some debris still remains on the filter following the ultrasonic procedure, we may scrub the filter with a soft nylon brush or a swab before flushing the filter with demineralized (DM) water.
The forward flow cleaning method involves flushing contaminants out of the filter. During this process, the filter is submerged in DM water in an ultrasonic tank. Next, the filter inlet is connected to a solvent flushing station supply port, while the filter outlet is routed to return. A solvent will flow from the inlet to the outlet.
In the next step, the ultrasound tank is turned on for at least thirty minutes. Then we activate a pump, which starts the flushing operation. The flushing operation is allowed to run for 5 minutes, after which the cleaning process is complete.
The reverse flow cleaning process is identical to forward flow cleaning, with one key difference: the filter outlet is connected to the solvent flushing station supply port, and the inlet is routed to return. This causes the solvent to flow the opposite direction.
The fourth and final cleaning process is called impingement. We begin this procedure by submerging the filter in a solvent in an ultrasonic tank, subjecting it to ultrasonic waves for 10-30 minutes, and then performing an impingement spray on the interior and exterior surfaces of the filter.
Impingement is basically a form of pressure washing. It involves spraying the filter at a high enough pressure to remove debris and contaminants without damaging the filter membrane.
Below are the top three benefits of filter cleaning.
The main benefit of filter cleaning is it helps industrial companies save money on filter replacements.
When performed properly (by professionals), cleaning processes such as the ultrasonic method restore filters to 100 percent functionality.
The four filter cleaning methods we discussed in this article work for multiple types of filters.
In case you’re curious about the types of filter elements that can be cleaned using the above methods, here are four of the most common ones.
Dutch Twill, Wire Mesh
Twill Dutch wire mesh combines the Dutch and twill weaving processes to produce an extremely fine mesh filtering cloth. It is created by passing Shute wires over and under two warp wires. This process packs a greater volume of wires into a given area, resulting in finer mesh counts and lower flow than standard Dutch weaves.
Stack disc filters are any and all multiple “etched” disc assemblies, supported and compressed by a mechanical, screw-type inner core.
Sintered filters consist of tiny spheres of metal that are pressed, heated, and bonded together. The sintered material removes particulates from the process media by trapping them within its own structure.
Sinter bonded filter elements are used in low flow systems, typically to filter gas.
Depth filters are made of tiny, separate strands of material, pressed and heat fused together in a random pattern to form a “tortuous” path filter element. The surface of the depth filter is smooth to the touch, and no discernable weave pattern can be seen in the material.
The processes of filter cleaning, while effective, are also delicate. They require skill and expertise to perform properly so that the filter retains its integrity.
At PFC, we provide safe and professional filter cleaning backed by years of experience and the highest quality cleaning equipment. Contact us today to learn more.