For filtration, we need to pay attention not only to the selection of the cartridge but also need to pay attention to the inspection of the filter. The first thing you need to do after receiving a filter housing is to check every detail of it and test its performance of it.

Most cartridge filter housings are made of stainless steel and fiberglass materials, which are available in multiple round configurations and structures. We are willing to help you inspect all kinds of different cartridge filter housings. Read this blog and follow the directions, you could be a cartridge filter housing expert as well.

First step: Package checking

Package checking

Stainless steel cartridge filter housings after fabrication are normally packed into paper cartons or wood cases. Packages of housings have to be rigid and strong enough to endure accidental pressure during shipment.

Inside the package, we need to ensure that no moving or shaking happens in the packing box. Otherwise, during the long journey of transportation, damages may be caused to the cartridge filter housing, and future filtration performance could be affected.

Stainless steel cartridge filter housings

What’s more, the filter housing must be covered by a packing membrane on every corner before being put into the carton/case. Scratches can be avoided to keep the filters in good status when customers receive them.

There is one more tip for you when your cartridge filter housings are equipped with outside painting, please check with the supplier whether they have put one more extra small tank of painting inside the package.

Because some marks or defects might be caused on the finishing surface when unloading the cartridge filter housing to the operation site. It will be easy to repair if you have the same color painting on hand. This convenience service will also help you to gain more satisfaction from your cartridge filter housing end users.

Second step: Product checking

Now let’s move on to the real challenge, the whole checking, and testing for cartridge filter housing. It will take some time and effort to accomplish the checking process, but for the perfect filtration performance, it is worth doing.

Hydro test report

After welding, very cartridge filter housing will go through a hydro test under a pressure even larger than the design pressure for a fixed period after. It is for the assurance that no leakage problem and complete integrity sealing under the expected operating environment. It is important and essential to archive all the test reports and videos, which are the best evidence to show the performance of the filter housing.

Inspection for welding procedure

Communicate with the manufacturer timely, if a root opening needs to be left. If the root opening is too tight, an inadequate penetration can be caused. However, a larger root opening can cause an over-penetration.

Same principle to the groove angles. If groove angles are too small, may cause a lack of fusion, and if too large, can result in distortion of the weld joint from overheating and excessive shrinkage stress.

Check the physical appearance of the weld seam. The good weld seam is continuous, average, and neat like a fish scale. Cautions need to be paid on the surface discontinuities. It might represent other discontinuities within the body of the weld.

The most common weld discontinuities found during the visual inspection were undersized welds, nibbling, lap joints, surface cracking, surface porosity, bottom filling, incomplete root penetration, excessive root penetration, burn through, and excessive reinforcement.

Good welding before surface finishing is gold color as below the first picture. Good welding on the final product is in a continuous fish scale pattern, as below the second picture.

Inspection for welding procedure
Inspection for filter housing parameters

Inspection for filter housing parameters

At this point, a key factor is the drawing design of the filter housing. You’d better print out the technical drawing of the housing and double-check every detail of it. Make sure that all elements are the same as the drawing design. You need to pay attention to the following factors.

Materials identifying

Many materials can be chosen for filter housings, and we need to identify whether the materials accord with the requirement and materials are based on the contracts.

Materials identifying

Taking our Stainless Steel Filter Housing as an example, generally, the body, up closure, bottom closure, in/outlets are made of stainless steel 316 while the davit arm or the legs might be stainless steel 304. Customization is available by many manufacturers, all stainless steel 316 made is also acceptable.

At this point, verifying the materials of all parts is important.

Davit arm or swing arm

Generally, a davit arm is equipped with filter housings that load more than 12~15 pcs filter cartridges. But it can be customized with any amount of filter cartridges. So when you received filter housing, remember to check the condition of the davit arm, and make sure it meets the standard.

Davit arm or swing arm

Closure design: Clamp, swing bolt, and Flange

There are three different designs for closure, which are clamp, swing bolt and flange. Clamp is suitable for low operation pressure around 4Bar. Both swing bolt and flange are designed for higher operation pressure around 6~7Bar.

When opening the lid during maintenance, using a swing bolt design is more convenient. Accordingly, it costs more, because it needs more welding processes compared to Flange. The flange is easy to accomplish and only needs hole drilling.

After you receive the filter housing, don’t forget to check the closure design, which should be conformed to the requirement.

Body diameter and shell thickness

The max design pressure is mainly determined by body diameter. The higher pressure of cartridge filter housing requires a thicker shell.

Checking all these dimensions is also important for your filter housing inspection.

In/outlet design and type

Many different directions are offered for inlet and outlet. For inlets, there are side-in and top-in designs. Side-out and bottom-out are both available for an outlet. According to the customer’s need, a side-in and side-out type of filter housing can be made at the same side or on different side.

Flange and thread types of inlet/outlet ports can be optioned by customers. Based on various country’s standards, different flange size can be provided. To check and measure the inlet/outline details, make sure no mistakes on filter housings.

Seat plates for the cartridge filters

DOE, SOE 222/FIN, SOE 226/FIN, and so on, different cartridge filters are suitable for different seat plates. Checking the seat plate, that is matched with your filter cartridges.

Seat plates for the cartridge filters

Surface finish checking: painting, acid passivation, polishing, and sandblasting

Compared with other factors, the surface finish is conspicuous and more obvious. It can be confirmed at first sight.

Surface finish checking


The filter housing is also something crucial for filtration. Facing different operating conditions, it can be made of different materials and different flow directions with the optional sealing method. Generally, filter housings travel a long journey to the consumers.

Damages might be caused during the transportation and sometimes complex design requirements may confuse manufacturers, so the checking and inspection of filter housings are very essential. The only filter housing and filter cartridge are both in good condition and can perform good filtration.

Brother Filtration would like to help you solve any problem with filtration. We have years of experience in the filtration area, and produce all kinds of filter products. If you want to know more about filter housing, please feel free to contact us.

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