German REXROTH Rexroth solenoid valve Aventics

German REXROTH Rexroth solenoid valve Aventics

The selection of solenoid valves should first follow the four principles of safety, reliability, applicability, and economy. Secondly, the selection should be based on six aspects of on-site conditions (i.e. pipeline parameters, fluid parameters, pressure parameters, electrical parameters, action mode, and special requirements).
Solenoid valve is an industrial equipment controlled by electromagnetic force, which is an automation basic component used to control fluids. It belongs to actuators and is not limited to hydraulic and pneumatic systems. It is used in industrial control system to adjust the direction, flow, speed and other parameters of medium. Electromagnetic valves can be used in conjunction with different circuits to achieve the desired control, while ensuring the accuracy and flexibility of the control. There are many types of solenoid valves, and different solenoid valves play a role in different positions of the control system, such as one-way valves, safety valves, directional control valves, speed regulating valves, etc. Principle: It is a combination of direct action and pilot operated principle. When there is no pressure difference between the inlet and outlet, after being 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 inlet and outlet reach the starting pressure difference, after being energized, the electromagnetic force pilot small valve, the lower chamber pressure of the main valve rises, and the upper chamber pressure drops, thereby using the pressure difference to push the main valve upwards; When the power is cut off, the pilot valve uses spring force or medium pressure to push the closing member downwards, causing the valve to close.
Features: It can also operate under zero pressure difference, vacuum, and high pressure, but with high power, it must be installed horizontally.
Pilot operated solenoid valve
Principle: When powered on, the electromagnetic force opens the pilot hole, causing the pressure in the upper chamber to rapidly decrease, creating a pressure difference of high and low around the closing element. The fluid pressure pushes the closing element to move upward, and the valve opens; When the power is cut off, the spring force closes the pilot hole, and the inlet pressure quickly forms a lower and higher pressure difference around the closing valve through the bypass hole. The fluid pressure pushes the closing valve to move downward and close the valve.
Features: The upper limit of the fluid pressure range is relatively high, and it can be installed freely (customized), but it must meet the fluid pressure difference conditions.
2REXROTHElectromagnetic valves are divided into six sub categories based on 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, and pilot piston structure.
3. Electromagnetic valves are classified according to their functions: 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, miniature solenoid valves, pulse solenoid valves, hydraulic solenoid valves, normally open solenoid valves, oil solenoid valves, DC solenoid valves, high-voltage solenoid valves, explosion-proof solenoid valves, etc. Selection criteria:
1. Select the solenoid valve based on pipeline parameters: diameter specification (i.e. DN), interface method
1) Determine the diameter (DN) size according to the on-site pipeline inner diameter size or flow requirements;
2) Interface method, generally>DN50 requires flange interface, ≤ DN50 can be freely selected according to user needs.
2. Select the material and temperature group of the solenoid valve based on fluid parameters
1) Corrosive fluids: corrosion-resistant solenoid valves and all stainless steel should be selected; Edible ultra clean fluid: It is recommended to use food grade stainless steel solenoid valves;
2) High temperature fluid: It is necessary to choose electromagnetic valves made of high-temperature resistant electrical materials and sealing materials, and to choose piston type structures;
3) Fluid state: up to gaseous, liquid, or mixed state, especially when the diameter is greater than DN25, it must be distinguished;
4) Fluid viscosity: Usually below 50cSt, it can be freely selected. If it exceeds this value, a high viscosity solenoid valve should be used.
3. Selecting solenoid valves based on pressure parameters: principles and structural types
1) Nominal pressure: This parameter has the same meaning as other general valves and is determined based on the nominal pressure of the pipeline;
2) Work pressure: If the work pressure is low, the principle of direct action or step-by-step direct action must be selected; When the working pressure difference is above 0.04Mpa, direct acting, step-by-step direct acting, and pilot operated can all be selected.
4. Electrical selection: The voltage specifications should preferably be AC220V or DC24, which are more convenient.
5. Choose based on the duration of continuous work: normally closed, normally open, or continuously powered on
1) When the solenoid valve needs to be opened for a long time and the duration exceeds the closing time, the normally open type should be selected;
2) If the opening time is short or the opening and closing time is not long, choose the normally closed type;
3) However, for some working conditions used for safety protection, such as furnace and kiln flame monitoring, the normally open type cannot be selected, and the long-term electrified type should be selected.
6. Select auxiliary functions according to environmental requirements: explosion-proof, check, manual, waterproof fog, water shower, and diving.

German REXROTH Rexroth solenoid valve Aventics