Teach you how to choose a hydraulic control valve

Hydraulic control valves are the components with the most varieties and specifications and the most widely used in hydraulic technology. What are the types and performances of commonly used hydraulic control valves? How should we choose?

1. Type. The type of valve should be selected according to the working characteristics of the system. For example, ordinary hydraulic valves, superimposed valves or cartridge valves can be used for hydraulic transmission systems mainly based on power transmission. For occasions requiring high control performance, electro-hydraulic control valves are selected, and the type and specification of the valve and its supporting electric control amplifier can be selected according to the control content, control accuracy, response characteristics, and stability of the actuator.

2. Specifications and models, specifications and models of various hydraulic control valves, based on the maximum pressure of the system and the actual flow through the valve, taking into account the control characteristics, stability, oil port size, external dimensions, installation and connection methods, operation methods, etc. of the valve , choose from a catalog or brochure.

3. Actual flow, rated pressure and rated flow. The actual flow of the hydraulic valve is related to the series and parallel connection of the oil circuit; the flow of each oil circuit in series is equal; the flow of the parallel oil circuit working at the same time is equal to the sum of the flow of each oil circuit. In addition, for a system using a single piston rod hydraulic cylinder, attention should be paid to the difference in oil return flow when the piston is extended and retracted.

4. The rated pressure and rated flow of each hydraulic valve should generally be close to its operating pressure and flow. For systems with high reliability requirements, the rated pressure of the valve should be higher than its working pressure. If the rated pressure and rated flow rate are lower than the operating pressure and flow rate, it will easily cause hydraulic clamping and hydraulic force and have an adverse effect on the working quality of the valve; for the sequence valve and pressure reducing valve in the system, the flow rate should not be much lower than the rated flow, otherwise vibration or other unstable phenomena may easily occur. For the flow valve, attention should be paid to its minimum stable flow.

5. The installation and connection method, because the installation and connection method of the valve has a decisive influence on the structural form of the subsequent design of the hydraulic device.

6. Volume and structure. When the working flow rate of the hydraulic system is below 100l/min, superimposed valves can be selected first, which will greatly reduce the number of oil circuit blocks, thereby reducing the volume and weight of the system; the working flow rate of the system is 200l/min In the above cases, the cartridge valve can be preferred, because a series of advantages of the cartridge valve can be fully utilized; when the system flow rate is 100l-200l/min, the conventional plate valve is preferred.

7. Price: when achieving the same function, compared with valves of the same specification but different types, the price of the conventional plate hydraulic valve is the lowest, followed by the superimposed valve, and the highest price of the cartridge valve. With the increase of domestic manufacturers of stacked valves and cartridge valves and the continuous improvement of technology, their prices will be close to those of conventional valves.

8. Supply of goods. The domestic production of conventional valves has a long history and many manufacturers, and the technology is relatively mature, so the supply of goods appears to be sufficient and the price is low.