Brilliant introduces you to what is a throttle valve? What is an overflow valve


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First, the throttle valve

(1) Throttle valve is a valve that controls the flow of fluid by changing the throttle section or throttle length. A flow control valve and a check valve can be combined in parallel to form a check flow control valve. Throttle valve and one-way throttle valve is a simple flow control valve, in the quantitative pump hydraulic system, the throttle valve and the relief valve are coordinated, which can form three throttle speed regulation systems, namely the inlet throttle speed regulation system, the return circuit throttle speed regulation system and the bypass throttle speed regulation system.

(2) The throttle valve does not have a negative flow feedback function, which cannot compensate for the speed instability caused by load changes, and is generally only used in occasions where the load changes little or the speed stability is not required. A hydraulic pressure control valve. In hydraulic equipment, it mainly plays the role of constant pressure relief and safety protection.

(3) The performance requirements for the throttle valve are: 1. The flow adjustment range is large, and the flow pressure difference changes smoothly; The amount of internal leakage is small, if there is an external leakage of oil port, the external leakage amount should also be small; The adjustment torque is small and the action is sensitive.



Second, the relief valve

(1) Constant pressure relief effect of the relief valve: In the quantitative pump throttling adjustment system, the hydraulic oil pump provides a constant flow. When the system pressure increases, the flow demand decreases. At this time, the relief valve is opened, so that the excess flow overflows back to the oil tank, and the pressure at the inlet of the relief valve is guaranteed, that is, the pump outlet pressure is constant (the valve port is often opened with pressure fluctuations).

(2) Safety protection: when the system is working normally, the valve is closed. Only when the load exceeds the specified limit (the system pressure exceeds the set pressure), the relief is turned on and overload protection is carried out, so that the system pressure does not increase (usually the set pressure of the relief valve is 10%~20% higher than the maximum working pressure of the system).

(3) Practical applications generally include: as a discharge valve, as a remote pressure regulating valve, as a high and low pressure multi-stage control valve, as a sequence valve, used to generate back pressure (string on the return circuit). Relief valves generally have two structures: 1. Direct-acting relief valves. 2. Pilot type relief valve.