Chlorine dioxide is widely used as a bleaching agent in the pulp and paper industry. This chemical also has widespread use as a disinfectant in the wastewater management, and chemical, pharmaceutical, and food processing industries.
As a compound, chlorine dioxide is toxic and hazardous. Inhaling the vapours can cause pulmonary edema, while skin contact can result in irritation and burning. Chlorine dioxide gas is also highly flammable and reactive, presenting a significant fire and explosion hazard.
Applications requiring gaskets for chlorine dioxide service require the use of gaskets that reliably seal while withstanding the aggressive chemical attack. CRG often recommends gaskets for chlorine dioxide service that are manufactured from Tealon, PTFE or Viton® materials. These gaskets and materials are discussed below.
Gaskets from Tealon TF1580 sheet
Gaskets made from Tealon TF1580 sheet are suitable for applications involving caustic media. Tealon TF1580 sheet is filled with barium sulfate and is suitable for strong caustic fluids. It meets FDA conformance for service within food and pharmaceutical applications. TF1580 can be used in a wide range of applications due to its vast resistance to most chemical products. It is compatible with strong acids along with strong caustics, making it the most diverse material within the Tealon family. With the off-white color of TF1580, gaskets made from this material are also suitable for processes where contamination is not tolerated. Tealon 1580 is approved by DVGW, TA-Luft, FDA, BAM, and the Chlorine Institute.
Made from a polymer with exceptional chemical resistance, Polytetrafluoroethylene (PTFE) gaskets are widely used for the sealing of aggressive chemicals, such as chlorine dioxide. The only media that can chemically attack PTFE are liquid alkaline metals and free fluorine. PTFE gaskets have excellent properties for electrical insulation, anti-stick, impact resistance and an extremely low coefficient of friction.
Extruding, laminating and sintering either pure PTFE or mixed with other materials, results in gasket products with distinct physical and chemical properties to meet the needs of each sealing application. CRG offers PTFE gaskets for chlorine dioxide service that are made from two styles of PTFE sheet:
Structured PTFE gasket sheet
To reduce creep in a finished gasket, structured PTFE sheet is used. With structured PTFE sheet, the gasket material is subjected to lamination before sintering, creating a highly multidirectional fibrillated structure. Creep, at both, room and high temperature, is substantially reduced. To meet the chemical resistance needed, different mineral or synthetic fillers are used, like Barite, mineral and synthetic Silica, Barite (Barium Sulphate) or Hollow-Glass-Micro-Spheres. Each filler meets specific service applications, with Barite filled sheet suitable for strong caustic service involving chemicals such as chlorine dioxide.
Expanded PTFE (ePTFE) gasket sheet
To minimize the creep associated with normal, sintered PTFE, expanded PTFE sheet uses a thermal expansion process before sintering. Gasket products expanded in one direction (cords or tapes) or multi-direction (tapes or sheets) are being produced this way. Expanded PTFE has excellent chemical resistance; it also exhibits very high compressibility and is therefore ideal for use with fragile or glass lined flanges. Its main drawback is the handling and installation of large gaskets or where it is not possible to separate the flange faces. It is often used as a replacement for the sheet filled with hollow glass microspheres.
Fluoroelastomers have become materials of choice for use in industrial equipment subjected to severe service conditions. Viton® is perhaps the most widely known example of a fluoroelastomer and is a registered trademark of The Chemours Company (formerly DuPont). Viton® is an excellent material choice for applications involving chlorine dioxide where optimal elastic properties and high mechanical strength are required.
CRG provides a wide range of material choices for buyers requiring gaskets for chlorine dioxide service. Our experienced team will be pleased to review your application and propose on the preferred material for your needs.
To find out more about the gaskets for chlorine dioxide service that CRG can supply, please contact our sales team at firstname.lastname@example.org.