Startventil

摘要

The valve comprises a housing with first and second apertures connected by a channel together with a piston (2) moving forwards and backwards between closed and open positions. The piston in the closed position works in conjunction with a valve seat (1c) and thereby closes the channel. A device is provided for maintenance of a low pressure medium flow, during the closed position of the piston, between an area with high pressure on the one side of the valve seat and an area in which pressure is building up on the other side of the valve seat. A spring component (5) impels the piston into the closed position. The piston has effective surfaces (2c-f) exposed to the high pressure and to the pressure which is building up. These surfaces produce force components, which impel the piston into its opening and closed positions. The piston moves into the opening position when the difference between the high and the building-up pressure is less than a threshold value.