Types of solenoid valves

Tracing the development history of solenoid valves, so far, solenoid valves at home and abroad are divided into three categories in principle (ie: direct-acting, step-by-step pilot-operated), and the differences in valve structure and materials The principle difference is divided into six sub-categories (direct-acting diaphragm structure, step-by-step re-plate structure, pilot diaphragm structure, direct-acting piston structure, step-by-step direct-acting piston structure, pilot piston structure).

  Principle of high-temperature solenoid valve: When energized, the electromagnetic coil generates electromagnetic force to lift the closing member from the valve seat, and the valve opens; when the power is off, the electromagnetic force disappears, and the spring presses the closing member on the valve seat and the valve closes. Features: It can work normally under vacuum, negative pressure and zero pressure, but the diameter generally does not exceed 25mm.

  Principle of distributed direct-acting solenoid valve: It is a principle that combines direct-acting and pilot-operated. When there is no pressure difference between the inlet and the outlet, the electromagnetic force directly lifts the pilot small valve and the main valve closing member in turn. The valve opens. When the inlet and outlet reach the starting pressure difference, after power on, the electromagnetic force pilots the small valve, the pressure in the lower chamber of the main valve rises, and the pressure in the upper chamber drops, so that the pressure difference pushes the main valve upward; when the power is off, the pilot valve uses a spring The force or medium pressure pushes the closing piece and moves downward to close the valve.

Features: It can be operated under zero pressure difference or vacuum and high pressure, but the power is large and it must be installed horizontally.

  Principle of pilot solenoid valve: When power is applied, the electromagnetic force opens the pilot hole to the magnetic turning column level gauge, the pressure in the upper chamber drops rapidly, forming a high pressure difference around the closing part, and the fluid pressure pushes the closing part to move upward, and the valve Open; when the power is off, the spring force closes the pilot hole, and the inlet pressure quickly passes through the bypass hole to form a low and high pressure difference around the closing valve member. The fluid pressure pushes the closing member to move downward and close the valve.

Features: The upper limit of the fluid pressure range is high, and it can be installed arbitrarily (customization is required) but must meet the fluid pressure difference condition.

  Installation and maintenance of the solenoid valve Read the product manual carefully before installation, check whether the product meets the requirements for use, remember the installation points, and make preparations. Check whether the parameters on the nameplate are consistent with the parameters of the selected product. The power supply voltage should meet the fluctuation range of the rated voltage: AC +10%~-15%, DC +10%~-10%. Usually the coil components should not be disassembled. Flush the pipeline with a pressure of 0.3 MPa before taking over the pipeline to remove the metal powder and sealing material residues in the pipeline, rust, etc. Pay attention to the cleanliness of the medium. If the medium is mixed with dirt, impurities, etc., which hinder the normal operation of the solenoid valve, a filter valve filter screen ≥ 60 mesh should be installed in the pipeline.

  Solenoid valve should not be installed in the low recess of the electric actuator pipe, installed in the discharge pipe of the container, pay attention not to lead out from the bottom of the container, but should be installed slightly above the bottom of the container. If the medium will have water hammer, you should choose a solenoid valve with waterproof hammer function or take corresponding preventive measures.

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