Metallized Carbon Corporation, a manufacturer of oil-free, self-lubricating, carbon-graphite materials for severe service lubrication applications, has announced the availability of carbon-graphite ball valve seats for use in valves designed to handle hot liquids or hot gases. The ball valve seats are available in more than 150 grades of Metcar’s proprietary carbon/graphite material.
The carbon-graphite ball seats are ideal for use in temperatures from approximately 350 F, where plastic ball valve seats begin to soften. They can be used in temperatures up to 800 degrees in oxidizing environments, where high temperature carbon-graphite materials start to oxidize. They are also excellent for fire safe petroleum industry ball valves, which must operate freely after a simulated fire test in which the valve is heated to 1400 to 1800 F.
The ball valve seats are produced by shrink fitting a carbon-graphite ring into a metal retaining ring, which is available in Carpenter alloys, Hasteloy, Inconel, stainless steels, steel and titanium. After shrink-fitting, the carbon-graphite is pre-stressed in compression and exhibits the same coefficient of thermal expansion as the metal retaining ring. The concave face of the carbon graphite ring is polished to make a pressure tight fit with the ball, and the back face of the carbon-graphite is lapped flat to make a pressure tight fit with the valve housing.
Metallized Carbon Corporation