What is the difference between electromagnetic directional valve and electrohydraulic directional valve?

- Jul 22, 2019-

The electromagnetic directional valve is divided into AC and DC electromagnetic directional valves. The AC electromagnetic reversing valve has large suction force and short commutation time, but the impact and the noise is large, and it is easy to burn when overloaded. The reliability is not as good as the DC electromagnetic reversing valve.The electromagnetic reversing valve has small starting force, long commutation time, small commutation impact, safe use and long service life. The electro-hydraulic reversing valve has smooth commutation and long commutation time, which is mainly composed of an electromagnetic reversing valve and a hydraulic reversing valve. The electromagnetic reversing valve functions as a pilot valve, and the hydraulic reversing valve functions as a main valve. A simple hydraulic system with an electromagnetic reversing valve

 General speaking,electromagnetic reversing valve for small flow, electrohydraulic reversing valve for high flow hydraulic system.


What is a balancing valve and what does it do?

  The balance valve, also known as the speed limit lock, is an externally controlled internal discharge type one-way sequence valve. It is used by a one-way valve and a sequence valve. In the hydraulic circuit, the oil in the hydraulic cylinder or motor oil circuit can be blocked. The liquid makes the hydraulic cylinder or motor not fall due to the load's own weight, and at this time it acts as a lock. When the hydraulic cylinder or the motor needs to move, the movement is achieved by passing the liquid to the other oil passage and simultaneously opening the circuit through the internal valve of the balance valve control sequence valve. Since the sequence valve itself is different from the structure of the two-way hydraulic lock, it is said that a certain back pressure is established in the working circuit during operation, so that the main work of the hydraulic cylinder or the motor generates a negative pressure due to the self-weight overspeed falling, so no Shock and vibration like a two-way hydraulic lock. Therefore, the balancing valve is generally applied to a circuit that has high speed and heavy load and has a certain speed stability requirement.

  Hydraulic locks, hydraulically controlled check valves, what are the two functions in the hydraulic system? What is the difference between the pressure relief valve and the relief valve? What is the speed control valve used for? Adjust the flow? Is the flow rate of the pump adjusted?

  The function of the relief valve: overflowing the excess hydraulic oil in the hydraulic system and maintaining a certain pressure on the oil in the hydraulic system. It can also be used to prevent the system from being overloaded and to provide safety protection.

  The role of the pressure reducing valve: used to reduce the pressure of a part of the hydraulic system, so that this part gets a lower steady pressure.

  The hydraulic lock is often used in combination with two hydraulic control check valves, which are respectively in the oil inlet and outlet, and the control direction is opposite. Generally, the position of the hydraulic cylinder is strictly locked in the system. The hydraulic control check valve can only control the oil passage in one direction; the relief valve controls the inlet pressure, the pressure reducing valve controls the outlet pressure, and the difference between the working principle of the hydraulic control check valve and the one-way valve

  Check valves are divided into two categories: ordinary check valves and pilot operated check valves. Ordinary check valves only allow liquid flow in one direction. Hydraulically controlled check valves have the function of a common check valve and are only controlled remotely. The mouth is controlled by a certain pressure, and the flow can be reversed. In the engineering application, two hydraulic control one-way valves are commonly used to form a hydraulic lock.

  The opening of the hydraulic pressure control valve is mainly used in the reverse direction.

  Mainly the forward direction can pass, when the reverse pass, the check valve needs to be opened by the reverse control oil circuit control, so that it can pass in the reverse direction.

  A check valve is generally a valve that allows a single flow of liquid to pass through, but not in the reverse direction. The main pump outlet is used to prevent backflow of hydraulic oil and damage the pump. Sometimes it is combined with other single valves to form valves with special functions, such as discharge relief valve; our pump In fact, it is also the simplest example, but his medium is gas instead of hydraulic oil. In order to make the hydraulic fluid flow backward under the permission of a certain license, combined with the characteristics of the hydraulic pressure, the pressure oil of another oil circuit is used. Control is performed, and when the reverse control pressure is greater than its set value, the spool is opened, and the main oil passage realizes reverse oil flow. Mainly used in front of hydraulic actuators for pressure protection.