Principle: normally closed direct-acting solenoid valve is energized, the solenoid coil generates electromagnetic suction to the spool lift, so that the closure away from the far open the valve seat sealing subopen; power failure, the electromagnetic force disappeared, relying on the spring force of the closure element to press the valve on the seat valve closure. (Normally open type and the opposite)
Characteristics: in a vacuum, negative pressure, zero differential pressure can work properly, DN50 can be installed arbitrarily, but the electromagnetic head volume is larger. If our company introduces the technology of HERION company to produce direct-acting solenoid valve can be used for 1.33 × 10-4 Mpa vacuum.
Second, recoil type solenoid valve
Principle: its principle is a combination of direct-acting and pilot, when the power is on, the solenoid valve will be the first auxiliary valve to open the main valve cavity pressure is greater than the upper cavity pressure and the use of differential pressure and solenoid valve at the same time to open the valve; when the power is off, the auxiliary valve to use the spring force or medium pressure to promote the closure of the parts, downward movement will be the valve closed.
Characteristics: In zero differential pressure or high pressure can also work reliably, but the power and volume is larger, requires vertical installation.
Third, pilot operated solenoid valve
Principle: When energized, the electromagnetic force drives the pilot valve to open the pilot valve, the main valve upper chamber pressure drops rapidly, forming a pressure difference between the upper and lower chambers of the main valve, relying on the pressure of the medium to push the main valve closure piece upward, the valve opens; power failure, the spring force to the pilot valve closure, the inlet medium pressure through the pilot hole into the upper chamber of the main valve to form a pressure difference in the upper chamber, thus making the main valve closed. Thus, the main valve is closed.
Characteristics: small size, low power, but the range of differential media pressure is limited, must meet the differential pressure conditions.
Two-position three-way solenoid valve is usually used in conjunction with a single-acting pneumatic actuator, two-position is two positions can be controlled: on - off, three-way is three channels through the gas, generally one channel connected to the gas source, the other two channels 1 with the actuator inlet connected to the actuator, 1 with the actuator connected to the exhaust port, the specific principle of operation can be referred to the single-acting pneumatic actuator working principle of the diagram. The specific working principle can be referred to the working principle diagram of single-acting pneumatic actuator.
Two-position five-way solenoid valve is usually used in conjunction with double-acting pneumatic actuator, two-position is two-position controllable: on-off, five-way is five-channel ventilation, one of which is connected to the air source, two with the double-acting cylinder of the external chamber of the inlet and outlet connections, two with the internal chamber of the inlet and outlet connected to the specific working principle can be referred to the principle of double-acting pneumatic actuator
In the air circuit (the air circuit), the other two channels are connected to the actuator inlet, one with the actuator exhaust port connection, the specific operation principle can be referred to double-acting pneumatic actuators
In the gas circuit (or liquid circuit), two three-way solenoid valve has an inlet hole (connected to the inlet air source), an outlet hole (provided to the target device air source), an exhaust hole (generally installed a muffler, if you are not afraid of noise can not be installed @_@). The two-position five-way solenoid valve has an inlet hole (connected to the inlet air source), a positive-action outlet hole and a negative-action outlet hole (provided to the target equipment for one positive and one negative action air source), a positive-action exhaust hole and a negative-action exhaust hole (muffler is installed).For small automatic control equipment, the gas pipe is generally used 8 ~ 12mm industrial rubber gas pipe. Electrically, two three-way solenoid valve is generally a single electric control (i.e., single coil), two five-way solenoid valve is generally a double electric control (i.e., double coil). Coil voltage level is generally used DC24V, AC220V and so on. Two three-way solenoid valve is divided into two types of normally closed and normally open, normally closed type refers to the coil is not energized when the gas path is broken, normally open type refers to the coil is not energized when the gas path is open. Normally closed two three-way solenoid valve action principle: energize the coil, the gas path is connected, once the coil is de-energized, the gas path will be disconnected, which is equivalent to the "point of action". Normally open type two three-way single electronically controlled solenoid valve action principle: energize the coil, the gas path is disconnected, once the coil is de-energized, the gas path will be connected, which is also "point". Two-position five-way double electronically controlled solenoid valve action principle: to the positive action coil is energized, then the positive action airway is connected (positive action air outlet), even if the positive action coil is de-energized after the positive action airway is still connected, will be maintained until the reverse action coil is energized. If the reverse action coil is energized, the reverse action air circuit is turned on (air is supplied to the reverse action air outlet), and even if the reverse action coil is de-energized, the reverse action air circuit is still turned on and will remain on until the positive action coil is energized. This is equivalent to "self-locking". Based on the two five-way dual electric control solenoid valve characteristics, in the design of electromechanical control circuit or the preparation of PLC programs, you can let the solenoid valve coil action 1 ~ 2 seconds, so that the solenoid valve coil can be protected from damage.
The solenoid valve is used in the liquid system to realize the liquid circuit or change the direction of liquid flow, it generally has a spool can be driven in the coil electromagnetism sliding spool, spool in a different position, the solenoid valve access will be different. The spool of the working position of a few, the solenoid valve is called a few solenoid valve: valve body interface, that is, the number of solenoid valve access, there are a few through the interface, the solenoid valve is called a few solenoid valve. Solenoid valve installation, generally all interfaces should be connected, the so-called working position refers to the position of the spool. Spool in the coil is not energized in the A position, in the coil is energized in the B position, the spool in different positions, the interface to play or connect or closed role.
Solenoid valve is a two-position solenoid valve spool has two different working positions (open, close). Solenoid valve two-way, three-way refers to the valve body of the solenoid valve has two, three channel port; for example, two-position two-way solenoid valve is an inlet and an outlet (two channels, the most common common) two-position three-way solenoid valve to control the liquid is an inlet and two outlets (two out of the two were a normally open and a normally closed); pneumatic directional solenoid valve is a one in and one out of the one exhaust; hydraulic in and one out of the one back to the oil.
Domestic and foreign solenoid valve is divided into three categories from the principle (i.e.: direct-acting, step-by-step direct-acting, pilot-operated), and from the valve valve structure and materials on the different principles of the difference is divided into six branches of subclasses (direct-acting diaphragm structure, step-by-step heavy piece of structure, pilot diaphragm structure, direct-acting piston structure, step-by-step direct-acting piston structure, pilot-piston structure).
Direct-acting solenoid valve:
Principle: when energized, the solenoid coil generates electromagnetic force to lift the shut-off piece from the valve seat, and the valve opens; when de-energized, the electromagnetic force disappears, and the spring presses the shut-off piece on the valve seat, and the valve closes.
Features: in vacuum, negative pressure, zero pressure can work normally, but the diameter is generally not more than 25mm.
Distribution of direct-acting solenoid valves:
Principle: it is a combination of direct-acting and pilot-operated principle, when there is no pressure difference between the inlet and the outlet, the energized, electromagnetic force directly to the pilot and the main valve closure of the valve upward in order to lift the valve open. When the inlet and outlet to start the pressure difference, energized, electromagnetic force pilot small valve, the main valve lower chamber pressure rises, the upper chamber pressure drops, thus using the pressure difference to push the main valve upward; power failure, the pilot valve using spring force or medium pressure to push the closing member, move downward, so that the valve is closed.
Features: in zero differential pressure or vacuum, high pressure can also be * action, but the power is larger, the requirement must be installed horizontally.
Pilot solenoid valve:
Principle: when energized, the electromagnetic force to the pilot hole open, the upper chamber pressure drops rapidly, the formation of a low pressure differential around the closing member, the fluid pressure pushes the closing member upward, the valve opens; power failure, the spring force to the pilot hole is closed, the inlet pressure through the bypass hole quickly chamber in the shut-off valve around the formation of a lower low on the high pressure differential, the fluid pressure pushes the closing member downward, the valve closes. The fluid pressure pushes the closing member to move downward and close the valve.
Features: Higher fluid pressure range upper limit, can be arbitrarily installed (need to be customized) but must meet the fluid differential pressure conditions