Patent ID: 6273686
Filing Date: 2001-08-14
Classification: F15B,G05D,Y10T

Abstract:
A pressure control system for maintaining a rated system pressure at a pressure input (I) and at a pressure output (O), said pressure control system comprising a pressure supply line (11, 8) for feeding fluid under pressure from said pressure input (I) to said pressure output (O), a pressure return line (9) for returning fluid to a pressure pump (1), a pressure relief valve (2) for connecting said pressure supply line (11) to said pressure return line (9) in response to an excess pressure in said pressure supply line (11, 8), a first pressure adjustment member (13) for adjusting a response pressure of said pressure relief valve (2), a check valve (4) connected in said pressure supply line (11, 8) between said input (I) and said output (O), a second pressure adjustment member (12) for adjusting a response pressure of said check valve (4), a pressure sensor (3) arranged for sensing an actual pressure in said pressure supply line to provide a respective actual pressure signal for operating said pump, a microcontroller (5) having an input connected to receive an output signal from said pressure sensor (3) for generating in said microcontroller (5) a pump control signal, a switch (10) for enabling said pump control signal when said pressure relief valve is to be adjusted to a higher or lower system pressure, a conductor (10A) connecting said switch (10) to said microcontroller (5), and means (16, 17) cooperating with said first and second pressure adjustment members for permitting an adjustment of said pressure relief valve (2) through said first pressure adjustment member (13) only if said second pressure adjustment member (12) is in a position signifying that said check valve (4) is open and said pump (1) is enabled through a signal from said switch (10).