Throughout the domestic and foreign solenoid valve, so far, from the action mode can be divided into three categories namely: direct-action, recoil-type, pilot-type, and from the disc structure and material differences and the principle of the difference between the recoil type can be divided into: diaphragm-type recoil solenoid valve, piston-type recoil solenoid valve; The pilot type can be divided into: pilot-type diaphragm solenoid valve, Pilot-type piston solenoid valve, from the seat and sealing materials can be divided into: soft seal solenoid valve, steel sealing solenoid valve, steel sealing solenoid valve.

Let's take a look at the three main categories of action.

Direct-Action solenoid valve

Principle: Constant closed-type Direct action solenoid valve when energized, electromagnetic coil to generate electromagnetic suction to lift the spool, so that the closing part from the far open valve seat sealed pair open, power off, the electromagnetic force disappears, by the spring force on the valve seat closed valve closed. (often open type is opposite)

Features: In the vacuum, negative pressure, 0 differential pressure can work normally, DN50 can be installed below, but the size of the larger electromagnetic head. such as my company introduced Herion company technology production of direct solenoid valve can be used to 1.33x10-4 MPa vacuum.

Second, recoil type solenoid valve

Principle: Its principle is a kind of direct movement and the forerunner unifies, when energized, the solenoid valve opens the auxiliary valve first, the main valve lower chamber pressure is larger than the upper chamber pressure and the use of pressure differential and solenoid valve at the same time to open the valve;

Features: in 0 pressure differential or high pressure can also work reliably, but the power and volume is large, requiring vertical installation.

Three, pilot-type solenoid valve

Principle: When energized, the electromagnetic force driving pilot valve opens the pilot valve, the main valve upper chamber pressure drops rapidly, in the main valve upper and lower cavities forming pressure difference, relying on the medium pressure to promote the main valve close to move, valve open, power off, the spring force to the pilot valve closed, the inlet medium pressure through the pilot hole quickly into the main valve upper chamber in the upper chamber to form a pressure difference, So that the main valve is closed.

Features: small size, low power, but the medium pressure range is limited, must meet the pressure difference conditions.

Two-bit three-wire solenoid valve is usually used with single acting pneumatic actuator supporting use, two-bit is two position controllable: on-off, the tee is three channel ventilation, generally 1 channels are connected with the air source, the other two channels 1 are connected with the actuator inlet, 1 are connected with the actuator vent port, The specific working principle can refer to the working principle diagram of the single acting pneumatic actuator. Two-bit five-pass solenoid valve is usually used in support of two-function pneumatic actuator, two-bit is two position controllable: open-close, five-pass is five channel ventilation, of which 1 are connected with the air source, two with the outer air Chamber of the double acting cylinder connection, two and the inlet and outlet of the internal gas chamber, The specific working principle can refer to the working principle of the double acting pneumatic actuator.

On the gas road (or Liquid Road), two-digit three-way solenoid valve has 1 air intakes (connected to the gas source), an air vent (provided to the target equipment gas source), an exhaust hole (general installation of a muffler, if not afraid of noise can not install @_@). Two-bit five-pass solenoid valve has 1 air intakes (connected to the gas source), 1 positive action vent holes and a reactionary gas vent (respectively provided to the target device one positive and one reverse action air source), 1 positive action exhaust holes and a reverse action exhaust hole (installation muffler).

For small automatic control equipment, the trachea is generally selected 8~12mm industrial rubber pipe. Electrically speaking, two-bit three-wire solenoid valve is generally a single electric control (that is, single coil), two-bit five-pass solenoid valve is generally dual-electric control (that is, dual-coil). Coil voltage grade generally uses dc24v, ac220v and so on. Two-digit three-way solenoid valve is divided into constant and often open type two, often closed-coil does not have power airway road is broken, often open type refers to the coil does not have power airway road is pass. Normally closed two-bit three-way solenoid valve action principle: to the coil power, air circuit, once the coil power off, the gas will be disconnected, which is equivalent to "point move."