Sealing in Steam

• withstands heat and corrosives

• resists swelling and compression set

A new fluoroelastomer sealing compound, specifically formulated to withstand the heat and corrosive effects of high temperature steam applications, has been developed by Pelmor Laboratories, Inc., a rubber products manufacturer. The new compound’s first application is as the modulator component in a pinch-style steam trap, recently developed and patented by Ogontz Corporation, manufacturer of temperature, pressure and flow control products. The steam trap was designed to eliminate the need for moving parts, which tend to wear out quickly in the hostile environment of high temperature steam. Specs called for the use of a compound with an orifice that would open at low temps and close at high temps. Another requirement was resistance to swelling and compression set, which can affect the orifice diameter. After experimenting with a number of compounds, Pelmor developed ZF9889.

Principal component of the compound is DuPont Dow Elastomers’ VITON GF terpolymer, an elastomer well known for its extraordinary performance characteristics in harsh service environments. VITON products are capable of withstanding temperature extremes of -40° to 400°F and are resistant to attack by the most aggressive chemicals and corrosive liquids, including concentrated nitric, sulfuric and hydrochloric acids, and others.

ZF9889 not only resists heat; it provides improved resistance to the corrosive and swelling effects of solvents as well as system cleansing agents, such as amines, which are typically used in steam applications. When exposed to steam temperatures as high as 475°F, the compound proved extremely durable, exhibited minimal swelling and compression set, and enabled the trap to perform to operating specs. Other high temp steam applications include steam trap seals, steam valve seals and static and dynamic sealing components.