Looking back at the development history of solenoid valves, so far, solenoid valves at home and abroad are divided into three categories in principle (namely: direct-acting, step-by-step direct-acting, pilot-operated), and from the perspective of valve structure and materials The differences and principle differences are divided into six sub-categories (direct-acting diaphragm structure, stepped diaphragm structure, pilot diaphragm structure, direct-acting piston structure, stepped piston structure, pilot piston structure).
(1) Direct-acting solenoid valve
Principle: When the power is turned on, the solenoid coil generates electromagnetic force to lift the closing member from the valve seat, and the valve opens; when the power is turned off, the electromagnetic force disappears, and the spring force presses the closing member against the valve seat, and the valve closes.
Features: It can work normally under vacuum, negative pressure and zero pressure, but the general diameter does not exceed 25mm.
(2) Step-by-step direct-acting solenoid valve
Principle: It is a principle that combines direct action and pilot type. When the pressure difference between the inlet and outlet is ≤ 0.05Mpa, when the power is energized, the electromagnetic force directly lifts the pilot small valve and the main valve closing member upward in sequence, and the valve opens. When the pressure difference between the inlet and outlet is >0.05Mpa, when the power is on, the electromagnetic force opens the pilot small valve first, the pressure in the lower chamber of the main valve rises, and the pressure in the upper chamber drops, thereby using the pressure difference to push the main valve upward; when the power is off, the pilot valve The main valve uses spring force or medium pressure to push the closing member and move downward to close the valve.
Features: It can work reliably under zero pressure difference, vacuum, and high pressure, but the power is large and requires vertical installation.
(3) Pilot solenoid valve
Principle: When the power is turned on, the electromagnetic force opens the pilot hole, and the pressure in the upper chamber drops rapidly, forming an upper, lower, and higher pressure difference around the closing member, pushing the closing member upward to open the valve; when the power is turned off, the spring force closes the pilot hole. , the inlet pressure quickly enters the upper chamber through the bypass hole, forming a lower pressure difference and a higher pressure around the valve closing member, pushing the closing member downward to close the valve.
Features: The upper limit of the fluid pressure range is very high, but the fluid pressure difference condition must be met.
Currently, the commonly used solenoid valves sold in China include more than a dozen varieties of DV (DVF), PGA, PEB (PESB), and BPE series, with diameters ranging from 3/4" to 3". They are mainly used for agriculture, gardening, golf, and industrial dust control. and fountains. Commonly used solenoid valves are mostly diaphragm valves. Their working principle is: the valve body is divided into upper and lower chambers, with a diaphragm in the middle. Under the same water pressure conditions, a pressure difference is generated due to the different stress areas of the upper and lower diaphragms, reaching the point of cutting off the flow of water. Purpose. Solenoid valve open state - when a power signal is given through the remote controller or the solenoid head is manually rotated, the drainage channel opens, the water in the upper diaphragm room is discharged, the indoor pressure decreases, the pressure acting on the upper diaphragm becomes smaller, and the upstream pressure acts Push the diaphragm upward to open the pipeline channel. Solenoid valve closed state - manually close or disconnect the electrical signal of the solenoid head, so that the drainage channel is closed, and the upper diaphragm chamber is slowly filled with water. When the pressure above and below the diaphragm is consistent, due to the larger stress area on the upper side of the diaphragm, large, causing the diaphragm to move downward and close the pipeline channel. The single solenoid control has only one solenoid head. After the power is supplied, the solenoid valve changes direction. After the power is lost, the solenoid valve resets due to the action of the spring. The double solenoid control 2-position solenoid valve has 2 solenoid heads, and only one of them can be powered. After the power is turned on, the solenoid valve changes direction. After the power is lost, the solenoid valve maintains its position. The solenoid head on the other side must be energized before the solenoid valve returns to its original position.
Looking back at the development history of solenoid valves, so far, solenoid valves at home and abroad are divided into three categories in principle (namely: direct-acting, step-by-step direct-acting, pilot-operated), and from the perspective of valve structure and materials The differences and principle differences are divided into six sub-categories (direct-acting diaphragm structure, stepped diaphragm structure, pilot diaphragm structure, direct-acting piston structure, stepped piston structure, pilot piston structure).
(1) Direct-acting solenoid valve
Principle: When the power is turned on, the solenoid coil generates electromagnetic force to lift the closing member from the valve seat, and the valve opens; when the power is turned off, the electromagnetic force disappears, and the spring force presses the closing member against the valve seat, and the valve closes.
Features: It can work normally under vacuum, negative pressure and zero pressure, but the general diameter does not exceed 25mm.
(2) Step-by-step direct-acting solenoid valve
Principle: It is a principle that combines direct action and pilot type. When the pressure difference between the inlet and outlet is ≤ 0.05Mpa, when the power is energized, the electromagnetic force directly lifts the pilot small valve and the main valve closing member upward in sequence, and the valve opens. When the pressure difference between the inlet and outlet is >0.05Mpa, when the power is on, the electromagnetic force opens the pilot small valve first, the pressure in the lower chamber of the main valve rises, and the pressure in the upper chamber drops, thereby using the pressure difference to push the main valve upward; when the power is off, the pilot valve The main valve uses spring force or medium pressure to push the closing member and move downward to close the valve.
Features: It can work reliably under zero pressure difference, vacuum, and high pressure, but the power is large and requires vertical installation.
(3) Pilot solenoid valve
Principle: When the power is turned on, the electromagnetic force opens the pilot hole, and the pressure in the upper chamber drops rapidly, forming an upper, lower, and higher pressure difference around the closing member, pushing the closing member upward to open the valve; when the power is turned off, the spring force closes the pilot hole. , the inlet pressure quickly enters the upper chamber through the bypass hole, forming a lower pressure difference and a higher pressure around the valve closing member, pushing the closing member downward to close the valve.
Features: The upper limit of the fluid pressure range is very high, but the fluid pressure difference condition must be met.
Currently, the commonly used solenoid valves sold in China include more than a dozen varieties of DV (DVF), PGA, PEB (PESB), and BPE series, with diameters ranging from 3/4" to 3". They are mainly used for agriculture, gardening, golf, and industrial dust control. and fountains. Commonly used solenoid valves are mostly diaphragm valves. Their working principle is: the valve body is divided into upper and lower chambers, with a diaphragm in the middle. Under the same water pressure conditions, a pressure difference is generated due to the different stress areas of the upper and lower diaphragms, reaching the point of cutting off the flow of water. Purpose. Solenoid valve open state - when a power signal is given through the remote controller or the solenoid head is manually rotated, the drainage channel opens, the water in the upper diaphragm room is discharged, the indoor pressure decreases, the pressure acting on the upper diaphragm becomes smaller, and the upstream pressure acts Push the diaphragm upward to open the pipeline channel. Solenoid valve closed state - manually close or disconnect the electrical signal of the solenoid head, so that the drainage channel is closed, and the upper diaphragm chamber is slowly filled with water. When the pressure above and below the diaphragm is consistent, due to the larger stress area on the upper side of the diaphragm, large, causing the diaphragm to move downward and close the pipeline channel. The single solenoid control has only one solenoid head. After the power is supplied, the solenoid valve changes direction. After the power is lost, the solenoid valve resets due to the action of the spring. The double solenoid control 2-position solenoid valve has 2 solenoid heads, and only one of them can be powered. After the power is turned on, the solenoid valve changes direction. After the power is lost, the solenoid valve maintains its position. The solenoid head on the other side must be energized before the solenoid valve returns to its original position.