At CRS we have several customizable filter options to fit your specific application. Below we have outlined some common questions in the selection process.

What Contaminants Can Be Filtered? 

We have filters that remove oxygen, moisture, hydrocarbons, carbon dioxide, and combo filters that remove several of these impurities. Other contaminants can be removed in trace amounts such as halogenated compounds, carbon monoxide, siloxanes, sulfur-containing molecules, and ammonia. You can use search filters on the website product pages to get a complete listing of which filters remove certain impurities or you can contact a CRS team member by phone, email, or online chat.

Do I Need Brass or Stainless Steel Fittings?

Before selecting brass for long-term applications, the local compliance rules should be studied. Brass alloys nearly always contain lead (3% by weight would be typical), and while presently permitted in most world markets, their status is under review. In some cases, special notifications might be required.

We are seeing labs switching to all steel tubing and fittings. If you have stainless steel tubing, then you should always use stainless steel fittings; and if you have copper tubing then you should use brass fittings. You may want to consider switching to all steel!

Using brass fittings on stainless steel tubing is not recommended. Brass is softer than steel and may not seal onto the tubing as well, risking leaks. You might also see galvanic corrosion, which is a process where the corrosion is accelerated by 2 dissimilar metals contacting one another.


Which Fitting Type Do I Need?

There are many kinds of fittings on the market for gas filters, including standard compression fittings, CRS quick connect fittings, and push to connect fittings to name a few.

Compression Fittings: These are by far the most common type of fitting found in all applications. An inner ferrule is compressed or “swaged” around the tube by the outer compression nut. The ferrule is designed either to bite into the tubing, or compress without biting, depending on the manufacturer. They seal well and the seal can be broken and re-made many times, but must not be over tightened.

In general, gas purifiers with stainless steel fittings should be used with stainless steel lines. Brass fittings are ideally used with softer copper tubing. It is not recommended to use stainless steel lines with brass or nickel-plated brass fittings (see Do I Need Brass or Stainless Steel Fittings? above).

Quick Connect Fittings: These have become more and more popular. They are used to provide a fast connection without tools. They have two parts, a male and female, that screw together to provide a make-or-break seal. Once they are installed on the gas lines, replacing the filters is much quicker and easier than compression fittings because the Quick Connect pieces have O-ring seals and check valves to protect the gas line from outside contaminants when they are disconnected (a benefit over competitor click-on fittings that do not reseal). Brass Quick Connects should be used with copper tubing and Stainless Steel Quick Connects should be used with stainless steel tubing.

Metal Push to Connect Fittings: These are used to connect plastic tubing only. The connection is quick and easy to make, just insert the plastic tubing into the fitting until it “clicks”. They are not recommended for carrier gas lines because of potential oxygen and water permeation through the tubing.

Which Fitting Size Do I Need?

Fitting size is determined by the gas line tubing size. 1/8” Fittings should go on 1/8” tubing and ¼” fittings should go on ¼” tubing.

How Do I Mount a Gas Filter?

Gas Filters should always be mounted vertically to ensure full capacity. For more information please see our blog “Gas Purifier Installation - Vertical or Horizontal?”.

We have several clip sets available for mounting gas filters into your laboratory setup. The correct set is determined by the size filter you have selected.

205705- The standard mounting kit is for use with our smaller 130 cc ZPure Filters, the glass indicating ZPure Filters, and our 88 cc and 116 cc SPure Filters.

205706- This wide filter mounting kit is for our wider filters: ZPure 500 cc and 750 cc filters, the SPure 240 cc and 400 cc Filters, and the Legacy Models 300, 500, 1000, and the Legacy CO2 Filter.

205707- This clip set is explicitly for our 475 cc ZPure LS Filters.

How Long Will This Filter Last?

There are many factors that determine how long a specific filter will last. To get accurate lifetime estimates on any CRS filters we will need to know the following:

  • Average flow rate
  • Usage: Hours a day that gas will be flowing through the filter
  • Contamination levels of each impurity in the source gas
  • Pressure

Gather your application information and fill out the form below to give us a complete picture of your application!

Purifier Recommendation and Lifetime Estimate