Gate valve in the two sealing surfaces are metal, we generally called as hard seal gate valve. This kind of gate valve sealing performance is poor, but high temperature resistance, anti-wear, good mechanical properties and long service life.
Metal Seat Gate Valve because it is a metal seal between. The valve body is required to do hardening treatment, the valve plate and the valve seat between the continuous grinding to make it achieve sealing. Hard seal gate valve production cycle is long.
Soft seal needs to be fireproof, high temperature will leak, while the hard seal will not leak. Emergency shut-off valve hard seal can be used under high pressure, soft seal can not be used.
General media containing solid particles or with wear and tear or temperature higher than 200 degrees is best to use the hard seal. For example, high temperature steam, generally about 180-350 ℃, you must choose hard seal gate valve.