Classification of hydraulic solenoid valves for press machines and cleaning steps for hydraulic valves

Classification of hydraulic solenoid valves for press machines and cleaning steps for hydraulic valves

The hydraulic solenoid valve of the press is a component used to control the pressure, flow rate and direction of the liquid in hydraulic transmission. Among them, the pressure control valve is called a pressure control valve and is classified into relief valves, pressure reducing valves and sequence valves according to its application.

(1) Relief valve: When the set pressure is reached, it can control the hydraulic system to maintain a constant state. The relief valve used for overload protection is called a safety valve. When the system malfunctions and the pressure rises to the limit value that may cause damage, the valve port will open and overflow to ensure the safety of the system.

(2) Pressure reducing valve: It can control the branch to obtain a stable pressure lower than the oil pressure in the main circuit. According to their different pressure control functions, pressure reducing valves can be classified into constant pressure reducing valves (with a constant output pressure), constant difference pressure reducing valves (with a constant pressure difference between the input and output), and fixed ratio pressure reducing valves (with the input and output pressures maintaining a certain proportion).

(3) Sequence valve: It can make one actuator (such as a hydraulic cylinder, hydraulic motor, etc.) act, and then make other actuators act in sequence. The pressure generated by the oil pump first pushes the hydraulic cylinder 1 to move, and at the same time acts on area A through the oil inlet of the sequence valve. When the hydraulic cylinder 1 is fully moved, the pressure rises, and the upward thrust acting on the area A is greater than the set value of the spring. The valve core rises, connecting the oil inlet and outlet, thereby causing the hydraulic cylinder 2 to move.

Cleaning steps for the hydraulic valve of the press:

The hydraulic valve of the press is designed to be non-detachable. Forcibly disassembling and reassembling it is very likely to damage the hydraulic valve. Therefore, before disassembly, one should master the structure of the hydraulic valve of the press and the connection method between its parts, and record the positional relationship between the parts during disassembly.

After disassembly, inspect the accumulation of dirt on the valve body, valve core and other components of the press, and clean the concentrated dirt with cotton yarn, brushes and non-metallic scrapers.

Clean the hydraulic valves of the press with hydraulic oil or working test oil. However, kerosene, gasoline, alcohol, steam or other liquids must not be used to prevent corrosion of hydraulic components, pipes, oil tanks and seals.

During the cleaning process, the valve body, valve core and other parts of the press should be placed on the tray of the cleaning tank for immediate hot soaking. Compressed air should be introduced to the bottom of the cleaning tank to clean the remaining dirt through the agitation of bubbles. If conditions permit, ultrasonic cleaning can be used. Non-metallic hammers can strike the oil pipe. The oil pipe can be continuously struck to remove the accessories in the pressure pipe.

After cleaning the hydraulic valve of the press according to the hydraulic assembly drawing or the part transfer relationship diagram recorded during the disassembly process, be careful not to damage the parts during the assembly process. The original sealing material is prone to damage during disassembly and should be replaced during assembly.