Selecting Wetted End Materials to Handle Chlorine Dioxide
Madden is going to start posting articles on common chemicals being pumped via the JN, MF, and MH Madden Pumps. The intention of this blog is to walk the reader through our process as to better understand how and why we come up with our recommendations.
Some of the more common, harsh chemicals we receive inquiries on and build pumps for are Sodium Hydrochloride, Chlorine Dioxide, and Sulfuric Acid.
So let’s start with Chlorine Dioxide.
Background of Chlorine Dioxide
There are over 1300 municipalities using Chlorine dioxide in the U.S.. to sanitize drinking water, disinfect waste water, rid water of odor and more. Several contacts have told us this substance is becoming more and more popular in the U.S.. and has been widely used in Europe for some time.
According to SABRE’s frequently asked questions page (companies specializing in solving problems and developing solutions related to biological and chemical contamination and pollution) Chlorine dioxide is a water-soluble gas with a slight yellow-green color and an odor similar to that of chlorine. The chemistry of chlorine dioxide is well established and documented through more than 70 years of safe utilization in a variety of industrial applications including:
- Disinfection of drinking water supplies
- Disinfection of wastewater flows
- Sterilization of pharmaceuticals and medical equipment
- Treatment of potentially infectious bio-medical waste
- Sanitization of food processing equipment
- Control of microbial growth in cooling water systems
- Preparation of food products such as flour, spices, shrimp, fruits and vegetables
- Bleaching of pulp to make paper products
- Elimination of odors from industrial processes and sewage systems
You can read more at SABRE’s website http://www.thesabrecompanies.com/faq.aspx
The Recommendation Process
At Madden we rely on a combination of documentation and experience. The documentation includes checking the chemical resistance of wetted end parts using at least three different charts to verify that the diaphragm, valve seats, valve balls, and so on will hold up to the chemical being pumped. However, just looking at charts isn’t always the best route. There are 3 individuals with 20+ years of experience each at Madden and you can’t replace experience. We also rely on customer experience as well. There are some times where a chart will claim a material will hold up to a certain liquid and end users tell us this simply isn’t true. They see it in use and in the field and we adjust to this information. The opposite can be true as well; on occasion an end user will relay information to us stating even though material X is generally stated as something that can’t hold up to the liquid, they have never had a problem.
So when it comes to Chlorine Dioxide, we commonly prescribe a double viton diaphragm, viton valve seats, and teflon balls. This is because Viton is a little less expensive but shows to hold up just as well as Teflon. The reason for the double diaphragm is for when the primary diaphragm wears out, the backup will keep the Chlorine dioxide from entering into the pump body and eating away at those interior components. The Teflon balls are used because they hold up well and cost very little. We would also suggest keeping a spare diaphragm on hand for operations where 24/7/365 pumping is required.
Some of the more frequently used materials that Chlorine Dioxide can, and can’t touch
PVC, CPVC, Viton, Teflon
Polypropylene, Carbon Steel, Stainless Steel, Neoprene
If you have a need to inject chemicals into another fluid give us a call or request a quote. We’ll work with you to find the best pump that will last as long as possible and keep your process running smoothly 24/7/365.