Pressure equalising system for hot chamber diecasting machine - uses relief valve inside piston, between pressure vessel and overflow tank

摘要

The injection head for a hot chamber diecasting machine has a hollow piston containing a valve member with a spring around it, tending to hold it closed. During injection, this valve member is forced back against the spring so that the chamber above the piston is connected to the space below. The upper chamber is connected to the pressure vessel and the lower chamber is connected to the overflow tank, so that pressure in the upper chamber is reduced when the valve opens. Between the valve chamber and the lower chamber, are channels through the piston. There is also a clearance inside the piston spindle for the valve member.