The difference between direct-acting solenoid valve and pilot-operated solenoid valve

With the advent of the industrialization era, the strong demand in the solenoid valve product market is increasing day by day, and it has become one of the products for fluid control automation. According to the opening working mode of solenoid valve, it can be divided into two commonly used categories, pilot-operated solenoid valve and direct-acting solenoid valve. However, if the model is selected improperly, it may easily cause the solenoid valve to not work, and at the same time have a certain impact on the safety of the working conditions. So how to distinguish the differences between the two and their respective characteristics so that they can be better applied? This article provides a detailed introduction. Please check the following introduction: The difference between direct-acting solenoid valves and pilot-operated solenoid valves withstand pressure : The pilot-operated solenoid valve can withstand greater hydraulic pressure than the straight-through solenoid valve. Response time: The starting speed of direct-acting solenoid valve is faster than that of pilot-operated solenoid valve, and it is mostly used in places with rapid cut-off. Because the pilot solenoid valve opens the small valve first and the main valve after power is supplied, while the direct-acting solenoid valve opens the main valve directly. Flow capacity: The flow capacity of the pilot solenoid valve is larger than that of the direct-acting solenoid valve. Generally, the CV value can reach more than 3, while the general CV value of the direct-acting solenoid valve is less than 1. Power and loss: The power and loss of the direct-acting solenoid valve are greater than those of the pilot type. Medium purity requirements: Pilot-operated solenoid valves have relatively high requirements for the purity of the circulating medium, while direct-operated solenoid valves are not so strict. Direct-acting solenoid valve: Direct-acting solenoid valve is generally used in small-diameter, low-pressure environments. When the valve of this structure is opened, it does not require the lowest pressure of the medium and starts at zero pressure. Therefore, compared with the pilot-operated solenoid valve, The starting speed of the valve will be faster, which is especially suitable for places that require quick shutoff. Features: The power consumption is larger than that of the pilot solenoid valve, generally between 5-20w. High-frequency energization can easily burn the coil, but the control is simple and the range of use is wide. It can work normally under vacuum, negative pressure and zero pressure, but the diameter generally does not exceed 50mm. Pilot-operated solenoid valve: Pilot-operated solenoid valve is generally used in large-diameter, high-pressure situations. When the valve of this structure is opened, the minimum pressure of the solenoid valve is required not to be less than 0.03MPa. There must be pilot pressure, otherwise it cannot opened. In addition, the flow capacity of pilot solenoid valves is larger than that of direct-acting solenoid valves, and generally the CV can reach more than 3. The requirements for the purity of compressed air are relatively high, and direct-acting ones are not so strict. Features: Small electromagnetic head, low power consumption, 0.1-0.2w, can be powered on frequently and for a long time without burning out, and it is energy-saving. The upper limit of the fluid pressure range is high and can be installed arbitrarily (customization is required), but the fluid pressure difference condition must be met. However, impurities in the liquid can easily block the pilot valve hole, so it is not suitable for liquid use. Taking the normally closed solenoid valve as an example, the action process is: (1) When the solenoid valve is powered, as shown in the figure below. The electromagnetic force generated by energizing the coil causes the pilot valve to open, and the medium flows to the outlet. The pressure in the upper chamber of the main valve drops rapidly. A pressure difference is formed in the upper and lower chambers of the main valve to overcome the spring force and then move upward. The main valve opens, the medium flows, and the solenoid valve Turn on. (2) When the solenoid valve loses power, it is as shown in the figure below. When the solenoid valve coil is powered off, the electromagnetic force disappears, the moving iron core resets under the action of the spring force, the pilot valve closes, the medium flows in from the guide hole, the pressure in the upper chamber of the main valve core increases, and under the action of the spring force Move downward, close the main valve, cut off the medium flow, and close the solenoid valve. The above is an introduction to the differences between direct-acting solenoid valves and pilot-operated solenoid valves. If you want to know more relevant information, please log in to Sunway Pneumatic www.diancifa.cc.