Primary Categories of Electromagnetic Valves
Electromagnetic valves are categorized by function:
Water Solenoid Valves, Steam Solenoid Valves, Refrigeration Solenoid Valves, Low-Temperature Solenoid Valves, Gas Solenoid Valves, Fire Solenoid Valves, Ammonia Solenoid Valves, Gas Solenoid Valves, Liquid Solenoid Valves, Micro Solenoid Valves, Pulsed Solenoid Valves, Hydraulic Solenoid Valves, Normally Open Solenoid Valves, Oil Solenoid Valves, DC Solenoid Valves, High-Pressure Solenoid Valves, Explosion-Proof Solenoid Valves, etc.
Electromagnetic valves are categorized into six subcategories based on their differences in valve structure, materials, and principles.
Direct-acting diaphragm structure, step-by-step direct-acting diaphragm structure, pilot diaphragm structure, direct-acting piston structure, step-by-step direct-acting piston structure, pilot piston structure.
Electromagnetic valves can be categorized into three main types: direct-acting, stepless direct-acting, and pilot-operated.
Direct-acting solenoid valve
There are two types: normally closed and normally open. The normally closed type remains closed when power is off. When the coil is energized, it generates an electromagnetic force, causing the moving armature to overcome the spring force and attract the stationary armature, directly opening the valve and allowing the medium to flow. When the coil is de-energized, the electromagnetic force disappears, and the moving armature resets under the spring force, directly closing the valve and stopping the medium flow. The structure is simple, the operation is reliable, and it operates normally under zero pressure difference and low vacuum conditions. The normally open type is the opposite. This includes electromagnetic valves with flow diameters less than φ6.
The principle is as follows: When energized, the electromagnetic coil generates an electromagnetic force to lift the open piece from the valve seat, opening the valve; when de-energized, the electromagnetic force disappears, and the spring presses the open piece onto the valve seat, keeping the valve open. (The opposite is true for normally open type.)
Features: Operates normally under vacuum, negative pressure, and zero pressure, but the diameter is generally no more than 25mm.
Step-Actuated Electromagnetic Valve
This valve combines a single and double opening mechanism, with the main valve and guide valve operating sequentially to directly open the main valve port via electromagnetic force and pressure difference. When the coil is energized, it generates an electromagnetic force to attract the moving and stationary cores, opening the guide valve port. Since the guide valve port is situated above the main valve port and the moving core is connected to the main valve core, the pressure in the upper chamber of the main valve is relieved through the guide valve port. Under the combined action of pressure difference and electromagnetic force, the main valve core moves upward, allowing the medium to flow through the main valve. Upon de-energizing the coil, the electromagnetic force disappears. The moving core, under the influence of gravity and spring force, closes the guide valve port. The medium then enters the upper chamber of the main valve core through the equalizing port, increasing the pressure in the upper chamber. Under the action of spring复位 and pressure, the main valve closes, and the medium flow is interrupted. The structure is rational, the operation is reliable, and it functions reliably even at zero pressure difference.
The Principle: It combines the direct-acting and pilot-operated principles. When there is no pressure difference between the inlet and outlet, upon applying power, the electromagnetic force directly lifts the pilot valve and the main valve's closure piece sequentially upwards, opening the valve. Once the pressure difference between the inlet and outlet reaches the startup threshold, upon applying power, the electromagnetic force causes the pilot valve to act first, increasing the pressure in the lower cavity of the main valve while decreasing the pressure in the upper cavity, thereby using the pressure difference to push the main valve upwards; when power is disconnected, the pilot valve uses spring force or medium pressure to push the closure piece downwards, closing the valve.
Features: Operates in zero pressure difference or vacuum, as well as high pressure conditions, but requires higher power and must be installed horizontally.
Pioneer Electromagnetic Valve
This electromagnetic valve is composed of a pilot valve and a main valve core, forming a passage assembly; it is normally closed, remaining in a closed state when not powered. When the coil is energized, the generated magnetic force attracts the moving and static cores, opening the pilot valve port, allowing the medium to flow towards the outlet. At this point, the pressure in the upper chamber of the main valve core decreases, becoming lower than the pressure on the inlet side, creating a pressure difference that overcomes the spring resistance and causes the main valve core to move upwards, achieving the purpose of opening the main valve port and allowing medium flow. When the coil is de-energized, the magnetic force disappears, and under the action of the spring force, the moving core resets to close the pilot valve port. At this moment, the medium flows into the balanced hole, increasing the pressure in the upper chamber of the main valve core, and under the action of the spring force, it moves downwards to close the main valve port. The principle of the normally open type is exactly the opposite.
The Principle: When power is applied, electromagnetic force opens the pilot orifice, causing the upper chamber pressure to rapidly decrease and create a pressure difference with lower pressure at the bottom and higher pressure at the top around the closure piece. The fluid pressure then pushes the closure piece upward, opening the valve. When power is disconnected, the spring force closes the pilot orifice, and the inlet pressure passes through the bypass hole, rapidly creating a pressure difference with lower pressure at the bottom and higher pressure at the top around the closure piece. The fluid pressure then pushes the closure piece downward, closing the valve.
Features: Compact size, low power, high upper limit of fluid pressure range, can be installed at will (customization required), but must meet the fluid pressure difference conditions.
