Output regulation in hydraulic and hydropneumatic systems

Claim 1

Apparatus for regulating the output of a system fed with a fluid medium irrespective of the instantaneous pressure in the system, said system having a primary line (31 a and b), the apparatus comprising a regulating device (20) connected to said primary line and including a throttling (21), which can be adjusted, an inlet connection (22) to said throttling and an outlet connection (23) connected to said throttling, which connections are connected to said primary line (31 a and b), a pre-set non-return valve (24), a spring-loaded non-return valve (25) fitted with a leakage connection (26), and further connections (27, 28, 29) for flow of medium between the connections and valves, a control line (32) connected with the connection (27) between the pre-set non-return valve (24) and the spring-loaded non-return valve (25), said pre-set non-return valve (24) sensing pressure drop at the throttling (21), and when this pressure drop reaches a certain value the non-return valve opens so that medium is transferred via the connection (29) to the connection (27), so that the pressure in the connection (27) and connected control line (32) increases, control device (34) for regulation of the quantity of flow to the primary line (31 a and b), said control device (34) comprising a spring-loaded piston (33) activated by increased pressure in control line (32) such that on the basis of the output pressure in the control line, the flow of medium to the primary line (31 a and b) is lower than said output pressure, when the pressure in the control line exceeds said output pressure, and is higher when the pressure in said control line is below said output pressure, whereby the pressure in the connection (27) and consequently the control line (32) will decrease continuously when the pre-set non-return valve (24) is closed, because the medium is pressed from the connection (27) through the leakage connection (26) in the spring-loaded non-return valve (25).