What is the working principle of different types of pressure reducing valves?

Valves have been widely used in various industries, suitable for pipes and equipment such as water and gas. Butterfly valve manufacturers, let us briefly explain the working principles of many different types of pressure reducing valves.
　　 1. Working principle of direct acting pressure reducing valve
　　 The pressure on the outlet side increases, the membrane moves upward, the valve opening decreases, the flow increases, the pressure drop increases, and the pressure behind the valve decreases; the outlet pressure decreases, the membrane moves downward, the valve opening increases, the flow decreases, and the pressure decreases. The droplets decrease and the pressure behind the valve increases. The outlet pressure behind the valve always maintains the constant pressure set by the setting adjustment screw.
　　 2. Working principle of direct acting bellows type pressure reducing valve
The pressure on the outlet side increases, the bellows moves upward, the valve opening decreases, the flow increases, the pressure drop increases, and the pressure behind the valve decreases; the pressure on the outlet side decreases, the bellows moves downward, the valve opening increases, the flow decreases small. The pressure drop decreases and the pressure behind the valve increases. The outlet pressure behind the valve always maintains the constant pressure set by the setting adjustment screw.
　　3. Working principle of pilot piston pressure reducing valve
　　 Tighten the adjusting screw, open the pilot valve cover, and the medium enters the piston from the inlet side. The area of ​​the plug is larger than the area of ​​the main valve cover. Push the piston down to open the main valve. After the valve is balanced, the pressure of the spring adjusts the opening of the pilot valve, thereby changing the pressure above the piston and controlling the opening of the main valve flap. Keep the pressure behind the valve constant.
　　4. Working principle of pilot membrane pressure reducing valve
　　 Operating Principle No. 3. The piston is slowed by the membrane, and the pressure in the upper chamber of the membrane is controlled by the bypass regulating valve.
　　5. Working principle of pilot membrane pressure reducing valve
　　When the adjusting spring is in the free state, both the main valve and the pilot valve are closed. When the handwheel rotates clockwise, the diaphragm of the pilot valve is downward, the pilot valve opens, the medium passes through the pilot valve to the top of the diaphragm, the main valve is pushed, the main valve opens, the medium flows to the outlet, and the cylinder enters the diaphragm under the pilot valve. The outlet pressure rises to maintain balance with the adjusted spring force. If the outlet pressure increases, the pilot diaphragm moves upward and the pilot opening decreases. At the same time, the flow rate of the medium entering the main diaphragm is reduced, the pressure is reduced, the opening of the main valve is reduced, the outlet pressure is reduced, and a new balance is reached, and vice versa.
　　6. ​​Working principle of combined pressure reducing valve
　　 Pressure reducing valve consists of main valve, pilot valve and globe valve. When the adjustment spring is in a free state, the main valve and the pilot valve are closed. Twist the adjusting screw, the medium pushes the pilot valve, enters the chamber 1 and the pressure balance of the adjusting spring, and enters the rubber film chamber 2 of the main valve. The rubber diaphragm is upward, the main valve is opened, and the medium flows to the outlet. The shut-off valve is opened to maintain the pressure at which the chamber 2 moves. The outlet medium is sent back to the upper chamber 3 of the rubber film and the chamber 4 below the pilot valve. When the outlet pressure increases, the diaphragm of the pilot valve moves upward, the opening degree of the pilot valve decreases, and the medium pressure of the chamber 1 decreases. The pressure in the chamber 2 drops, the rubber membrane of the main valve moves downward, the opening of the main valve decreases, the outlet pressure drops, and a new balance is reached, and the perception is the same.
　　7, working principle of lever type pressure reducing valve
　　 This is a pressure reducing valve that balances the pressure by the weight of the lever. Operating principle: When the lever is in a free state, the valve disc and the valve seat of the double valve seat are closed. Under the effect of the inlet pressure, the valve flap is pushed upward, and pressure is formed at the outlet end. Through the balance weight on the lever, adjust the weight to the required outlet pressure. When the outlet pressure exceeds a given pressure, due to the force of the middle pressure acting on the upper valve seat, the force on the valve seat is very large, forming a certain pressure difference, that is, the flap moves downward, reducing the throttle area, the outlet The pressure also drops, reaching a new balance (and vice versa).
　　 8. The working principle of pilot bellows type pressure reducing valve
　　Turn the adjusting screw to open the valve disc of the pilot valve, and the medium enters the piston from the inlet side. Since the area of ​​the piston is larger than the area of ​​the main disc, the piston is pushed down to open the main valve, and the pressure of the spring balance adjustment spring changes. The opening of the valve changes the pressure above the piston and controls the opening of the main flap to keep the pressure behind the valve constant.