1、 How it works
(1). Electromagnetic valve:
The electromagnetic valve is composed of solenoid coil (electromagnet), valve core and valve body. When the solenoid coil is electrified or cut off, it drives the valve core to move and make the fluid pass through the valve body or be cut off;
(2). Electric valve:
2、 Valve type:
(1). electromagnetic valve:
1) Two way electromagnetic valve: the valve body has an inlet and an outlet which are connected with the pipeline. There are two control modes: normally open (when the electromagnetic valve is powered on, the fluid is cut off), normally closed (when the electromagnetic valve is powered on, the fluid passes through the valve);
2) Three way electromagnetic valve: the three ports of the valve body are connected with the pipeline and have two holes, which can be used for three control modes: normally closed (the pressure port is closed when the power is off, the exhaust port is connected to the cylinder port, when the power is on, the pressure port is connected to the cylinder port, and the exhaust port is closed); when the valve is powered on, the pressure port is closed, and the cylinder port is connected to the exhaust port Air port), general type (allowing the valve to be connected to one of the normally closed or normally open positions);
3) four way electromagnetic valve: general operation and operation double acting cylinder, there are four or five pipeline connection ports, one pressure port, two cylinder ports and one or two exhaust (oil) ports.
(2). Electric valve:
1) Electric valve matching the valve body and electric angle travel actuator: the electric actuator rotates the valve plate angle to control and adjust the valve closing and control the flow of the pipeline. The rotation of the output shaft of the electric actuator is less than one week, i.e. less than 360 degrees, generally 90 degrees to achieve the valve opening and closing process control. This kind of electric valve is mainly butterfly valve, ball valve, plug valve, etc;
2) valve body and electric actuator with multi turn electric process control (>360 degree), the rotation of the output shaft of the multi turn electric actuator is greater than a week, that is, greater than 360 degrees. This kind of electric valve is mainly gate valve, stop valve, etc;
3) Electric valve matching the valve body and the direct stroke electric actuator (linear motion): the movement of the output shaft of the driving part of the electric actuator is linear motion, not rotation, and the opening and closing control is realized by lifting the valve plate. This kind of electric valve is mainly control valve, single seat control valve, double seat control valve, etc;
3、 Control mode
(1). The electromagnetic valve is driven by the coil, which can only play the role of opening or closing;
(2). The electric valve is driven by a motor. It takes longer time to complete the opening or closing action than the electromagnetic valve, and the flow can be adjusted by inputting current and voltage signals to the actuator. The general control signals are: current signal (4 ~ 20mA, 0 ~ 10mA) or voltage signal (0 ~ 5V, 1 ~ 5V).
4、 Application range:
(1). The electromagnetic valve is driven by the solenoid coil with small driving force, which is easy to be damaged by voltage shock. It is generally suitable for the pipeline with the diameter less than DN50 and below. The action time is short when opening and closing, and there is a special high-frequency electromagnetic valve, especially suitable for the pipeline with high action frequency or short switching time;
(2). The electric valve is usually driven by a motor, which is more resistant to voltage impact and has large driving force. It can control the valve with large diameter. Moreover, the electric valve can adjust the flow of the pipeline, which is especially suitable for the large diameter pipeline or the place where the pipeline flow is required to be adjusted;
(3). Generally, the electromagnetic valve can be reset after power failure, and the electric valve needs additional reset device;
(4). The medium suitable for electromagnetic valve is relatively wide, such as acid, alkali, water, gas, oil, steam and other media. However, there are high requirements for the viscosity and cleanliness of the medium. A filter should be installed before the installation of the electromagnetic valve to ensure the normal operation of the electromagnetic valve, with low leakage rate and high safety;
(5). The electric valve is not only suitable for controlling the general fluid medium, but also especially suitable for controlling pulp, sewage, medium containing fibers and tiny solid particles. The cleanliness requirement of the medium is not high, and the leakage rate should be higher than that of the electromagnetic valve.