Requirements for the Speed Control Valve in the Stretching Hydraulic Press
Requirements for the Speed Control Valve in the Stretching Hydraulic Press
1.Pressure Difference in the Oil Inlet and Outlet Cavities: The pressure difference in the oil inlet and outlet cavities refers to the pressure difference between the valve's oil inlet and outlet cavities when the throttling port is fully open and the nominal flow is passing through, generally around 1 MPa. A pressure difference that is too low affects the stability of flow since the pressure relief valve cannot compensate for the throttle valve, impacting the stable flow.
2.Flow Adjustment Range: A larger flow adjustment range is generally preferred for hydraulic press flow control, and the flow changes evenly during adjustment, indicating good adjustment performance.
3.Stable Flow: Stable flow refers to the flow at which the speed control valve operates normally, with a change rate not exceeding 10%, and no phenomenon of flow interruption. The stable flow of QF-type speed control valves and QDF-type one-way throttle valves is typically around 10% of the nominal flow.
4.Internal Leakage: Internal leakage, with the throttle valve fully closed, refers to the flow that leaks from the oil inlet cavity to the oil outlet cavity through the clearance between the spool and the valve body when the oil inlet cavity pressure is adjusted to the nominal pressure. Minimal internal leakage is required. Additionally, during the operation of the hydraulic press, the speed control valve should not be prone to blockages. The impact of temperature on the valve's flow should be minimal.