Patent ID: 7178335
Filing Date: 2007-02-20
Classification: F02C,F05D,G05D,Y10T

Abstract:
1. A pressure regulator comprising a housing, a metering spool movable within the housing to control the degree of opening of a metering orifice of the regulator, a first inlet through which hydraulic fluid at high pressure is supplied to said metering orifice, a first pressure chamber within the housing and containing hydraulic fluid at a reference pressure (P ref ) to which one end of said metering spool is exposed, compression spring means within said first pressure chamber and acting at one end against said one end of said metering spool, an outlet from the housing downstream of said metering orifice, for hydraulic fluid at regulated pressure (P reg ) from said metering orifice, a second pressure chamber containing hydraulic fluid at said regulated pressure P reg to which the opposite end of said metering spool is exposed, such that the metering position of the metering spool relative to the housing is a position of equilibrium between the force of the spring and P ref acting on one end of said metering spool and P reg acting on the other end of the metering spool, said equilibrium position changing to maintain a predetermined pressure difference (P diff ) between P ref and P reg , and the regulator further including an abutment against which the opposite end of said compression spring means reacts and a third pressure chamber containing hydraulic fluid at a control pressure (P con ) acting on said abutment, whereby the value of P con can be changed to adjust the position of said abutment relative to the housing of the regulator to change the pre-load of said compression spring means thereby to adjust the value of P diff .