What are the main features of Pneumatic solenoid valves, and how to judge the quality of Pneumatic solenoid valves
The main features of Pneumatic solenoid valves
The solenoid valve, as a valve accessory to the pipeline, is a device used to change the cross-sectional area of the passage and the direction of medium flow, and to control the movement of the conveyed medium. Its main features are:
1. External leakage is completely blocked, internal leakage is easy to control, and it is safe to use. Internal and external leakage of valves is one of the safety factors in on-site installation. Other valves, such as self-controlled valves, usually extend the valve stem and control the rotation or movement of the valve core by electric, pneumatic, or hydraulic actuators. This requires solving the problem of external leakage of the dynamic seal of the valve stem due to long-term operation. The solenoid valve works by applying electromagnetic force to the iron core sealed in the magnetic isolation sleeve. There is no dynamic seal, so external leakage is prone to blockage. For instance, due to the limited torque control of electric valves, they are prone to internal leakage and may even break the valve stem head. The solenoid valve has a simple structure, reliable sealing, and is easy to control internal leakage. Therefore, compared with other valves, Pneumatic solenoid valves are relatively safer to use and are even more suitable for corrosive, toxic, or high and low temperature media.
2. The solenoid valve itself has a simple structure and a low price. It is easier to install and maintain than other types of actuators, such as control valves. More significantly, the automatic control system it forms is simple. Since the solenoid valve is controlled by a switch signal, it is very convenient to connect it to an industrial control computer.
3. It features quick action, low power consumption, and a lightweight design. The response time of Pneumatic solenoid valves can be as short as a few milliseconds, and even pilot-operated Pneumatic solenoid valves can be controlled within tens of seconds. Because it forms a self-contained circuit, it responds more sensitively than other automatic control valves. A well-designed solenoid valve coil has very low power consumption and is an energy-saving product. Through an appropriate circuit arrangement, it can also be achieved that the valve position can be automatically maintained simply by triggering the action, and it does not consume power under normal circumstances. The greatest advantage of Pneumatic solenoid valves lies in their relatively small external dimensions, which not only save space but also are lightweight and aesthetically pleasing.
Observe.
4. The control accuracy adjustment is limited, and it is not applicable to certain media. Pneumatic solenoid valves usually have only two states: open and closed. The valve can only be in two extreme positions and cannot be continuously adjusted (there are many new ideas attempting to break through, but they are all still in the experimental and trial use stage). Therefore, the precision adjustment is subject to certain limitations. The solenoid valve has a relatively high requirement for the cleanliness of the medium. It is not suitable for media containing particles. If there are impurities, they must be filtered out first. In addition, due to the inapplicability of viscous media, the applicable viscosity range of the media is relatively narrow.
5. Diverse models and wide applications. Although Pneumatic solenoid valves have inherent shortcomings, their advantages are still very prominent. Therefore, they are designed into a wide variety of products to meet various needs and have extremely wide applications. The progress of solenoid valve technology is also centered around how to overcome inherent deficiencies and how to better leverage inherent advantages. From the perspective of the working principle, state, and characteristics of Pneumatic solenoid valves, the structure of Pneumatic solenoid valves is simple, and the working process is not complicated. As long as the design is reasonable and the operation is reliable during normal use, there are generally no problems. Moreover, when in normal use, since no sparks or dangerous temperatures are produced, the possibility of causing an explosion is very small. However, in a faulty state, due to the lack of necessary protection, the possibility of the solenoid valve causing an explosion hazard will increase significantly.
Ii. How to Judge the Quality of an electromagnetic Valve
The quality of an electromagnetic valve mainly depends on two aspects: the coil and the valve body. Therefore, the test should mainly focus on these two aspects. You can find a 24V power supply and connect it to the coil. If you can hear a sound, it indicates that both the coil and the valve core of the solenoid valve are normal and can be engaged normally. Then check if there is any leakage. If there is a gas source, it's best to directly connect the gas source, and you can determine if there is any leakage. If there is no gas source, block the air outlet and blow it out with your mouth. In addition, the coil can also be inspected with a multimeter.
1. Power on the solenoid valve, unplug the plug, and use a multimeter to measure if there is electricity.
2. When the solenoid valve is powered on, bring a thin steel wire close to the coil to see if there is any suction.
3. Repeatedly test the solenoid valve by turning it on and off. Use a very fine Allen wrench to poke the "small pit" in the brass color on the solenoid valve's axis to see if it can be sucked in and ejected.
The methods for detecting the quality of Pneumatic solenoid valves:
First, connect the medium to be controlled (pressurized liquid, gas < air >, with the pressure value being the middle of the solenoid valve's operating pressure range) to the solenoid valve, and then supply power to the solenoid valve coil. If the controlled medium undergoes a state change from on to off or from off to on, then the solenoid valve is in good condition; otherwise, there is a problem.
Common faults of Pneumatic solenoid valves
1. Short circuit or open circuit of the coil
Detection method: First, measure its on-off state with a multimeter. If the resistance value approaches zero or infinity, it indicates that the coil is short-circuited or open-circuited. If the measured resistance value is normal (approximately a few ohms), it does not necessarily mean that the coil is in good condition. Please conduct the following final test: Find a small screwdriver and place it near the metal rod inserted through the solenoid valve coil. Then supply power to the solenoid valve. If you feel magnetism, the solenoid valve coil is in good condition; otherwise, it is broken. Solution: Replace the solenoid valve coil.
2. There is a problem with the plug/socket
Fault phenomenon: If the solenoid valve is of the type with a plug/socket, there may be problems such as the metal spring plate of the socket or the wiring on the plug (for example, the power cord is connected to the ground wire), which prevent the power from being delivered to the coil. It is best to develop a habit: after the plug is inserted into the socket, screw on the fixing screw; after the coil is inserted into the valve core rod, screw on the fixing nut.
If the plug of the solenoid valve coil is equipped with an LED power indicator light, then when using DC power to drive the solenoid valve, it must be connected correctly; otherwise, the indicator light will not light up. In addition, do not swap power plugs with light-emitting diode power indicators of different voltage levels. This may cause the light-emitting diode to burn out/short-circuit the power supply (switch to a plug of a lower voltage level) or very weak light emission of the light-emitting diode (switch to a plug of a higher voltage level).
If there is no power indicator light, the polarity of the solenoid valve coil does not need to be distinguished (unlike transistor time relays with a DC coil voltage and intermediate relays with a DC coil voltage and a diode/resistor leakage circuit connected in parallel to the coil (most of these intermediate relays are original Japanese ones), which require polarity distinction).
Solution: Correct wiring errors, repair or replace plugs and sockets.
3. Valve core issue
Fault Phenomenon 1: When the pressure of the medium passing through the solenoid valve is normal, pressing the red manual button of the solenoid valve does not cause any response (the pressure medium does not show any on-off change), indicating that the valve core must be faulty. Solution: Check if there are any issues with the medium, such as whether there is a lot of water accumulation in the compressed air (sometimes the oil-water separator does not play a significant role, especially when the pipeline design is poor, there will be a lot of water accumulation in the compressed air passing through the solenoid valve), and whether there are many impurities in the liquid medium being passed through. Then remove the accumulated water or impurities in the solenoid valve and pipelines. If it still doesn't work, please repair or replace the valve core, or simply replace the entire solenoid valve.
Fault phenomenon 2: After inspection, it is found that the coil is the original one and the magnetic property is normal when the coil is energized, but the solenoid valve still does not act (at this time, the function of the manual button of the solenoid valve may be normal), indicating that the valve core is faulty.
Solution: Please repair or replace the valve core, or simply replace the entire solenoid valve.
Above is what the main features of Pneumatic solenoid valves are, and how to judge the quality of Pneumatic solenoid valves content, To learn more related information, visit https://www.joosungauto.com/.
