The development of electromagnetic valves has a long and rich history. To date, solenoid valves worldwide are generally categorized into three types based on their operating principles: direct-acting, step-by-step pilot, and pilot-operated. Additionally, depending on the valve structure and material differences, they can be further divided into six subcategories: direct-acting diaphragm type, step-byreshold structure, leading diaphragm type, direct-acting piston type, step-by-step piston type, and pilot piston type.
A direct-acting solenoid valve operates by using electromagnetic force generated when power is applied. This force lifts the closing member away from the valve seat, allowing the valve to open. When the power is turned off, the electromagnetic force disappears, and a spring pushes the closing member back onto the valve seat, closing the valve. One of the key advantages of this type is that it can function properly under vacuum, negative pressure, or zero pressure conditions. However, the flow passage is typically limited to around 25mm.
The direct-acting and pilot-type solenoid valve combines both direct action and pilot operation. When there is no pressure difference between the inlet and outlet, power is applied, and the electromagnetic force directly lifts both the pilot valve and the main valve's closing member, opening the valve. Once a pressure difference is established, the solenoid activates the pilot valve, causing the pressure in the lower chamber of the main valve to increase. This pressure then pushes the main valve open. When power is removed, the pilot valve closes, and the spring force or fluid pressure pushes the closing member down, resulting in the valve being closed. This type of valve is reliable even in zero-pressure, vacuum, or high-pressure environments, but it requires more power and must be installed horizontally.
A pilot solenoid valve works by using electromagnetic force to open a small pilot hole when power is applied. This causes the pressure in the upper chamber to drop rapidly, creating a pressure differential across the closing member. The fluid pressure then pushes the closing member upward, opening the valve. When power is turned off, the spring forces the pilot hole to close, and the inlet pressure flows through a bypass, creating a low pressure differential across the valve. This allows the fluid pressure to push the valve closed. These valves can handle high fluid pressure ranges and are often customizable for different applications, but they require specific pressure conditions to operate effectively.
Military Truck,Isuzu Military Truck,Fsr Military Truck,Isuzu Nps Military Truck
FUYA VEHICLE , https://www.fuyavehicle.com