Gate valve and butterfly valve both play the role of switching and regulating flow in pipeline use. Of course, there is still a method in the selection process of butterfly valve and gate valve. In order to reduce the depth of soil covering of the pipeline in the water supply network, generally larger diameter pipes are equipped with butterfly valves, which have little effect on the depth of soil covering, and strive to select gate valves.
What is the difference between butterfly valve and gate valve?
According to the function and use of gate valve and butterfly valve, the gate valve has small flow resistance and good sealing performance. Because the flow direction of the gate valve plate and the medium is at a vertical angle, if the gate valve is not switched in place on the valve plate, the scouring of the medium on the valve plate will make the valve plate vibrate. It is easy to damage the seal of the gate valve. Butterfly valve, also known as flap valve, is a kind of regulating valve with simple structure. Butterfly valve that can be used for on-off control of low-pressure pipeline medium means that the closing member (disc or butterfly plate) is a disc, which rotates around the valve shaft to achieve opening and closing. A valve that can be used to control the flow of various types of fluids such as air, water, steam, various corrosive media, mud, oil, liquid metal and radioactive media. It mainly plays the role of cutting and throttling on the pipeline. The butterfly valve opening and closing part is a disc-shaped butterfly plate, which rotates around its own axis in the valve body to achieve the purpose of opening and closing or adjustment. The butterfly plate is driven by the valve stem. If it turns 90°, it can complete one opening and closing. By changing the deflection angle of the disc, the flow of the medium can be controlled.
Working conditions and medium: Butterfly valve is suitable for conveying various corrosive and non-corrosive fluids in engineering systems such as producer, coal gas, natural gas, liquefied petroleum gas, city gas, hot and cold air, chemical smelting and power generation environmental protection, building water supply and drainage, etc. On the pipeline of the medium, it is used to adjust and cut off the flow of the medium.
The gate valve has an opening and closing member gate, the movement direction of the gate is perpendicular to the direction of the fluid, and the gate valve can only be fully opened and fully closed. To improve its manufactor ability and make up for the deviation of the sealing surface angle during processing, this gate is called an elastic gate.
When the gate valve is closed, the sealing surface can only rely on the medium pressure to seal, that is, only relying on the medium pressure to press the sealing surface of the gate to the valve seat on the other side to ensure the sealing of the sealing surface, which is self-sealing. Most gate valves are forcibly sealed, that is, when the valve is closed, the gate must be forced against the valve seat by external force to ensure the tightness of the sealing surface.
Movement mode: The gate of the gate valve moves in a straight line with the valve stem, which is also called OS&Y gate valve. Usually, there are trapezoidal threads on the lift rod. Through the nut at the top of the valve and the guide groove on the valve body, the rotary motion is changed into a linear motion, that is, the operating torque is changed into the operating thrust. When the valve is opened, when the lift height of the gate is equal to 1:1 times the diameter of the valve, the fluid channel is completely unobstructed, but this position cannot be monitored during operation. In actual use, the apex of the valve stem is used as a sign, that is, the position where it cannot be opened, as its fully open position. In order to take into account the lock-up phenomenon due to temperature changes, it is usually opened to the top position, and then back to 1/2-1 turn, as the position of the fully open valve. Therefore, the fully open position of the valve is determined according to the position of the gate (ie stroke). Some gate valve stem nuts are set on the gate, and the rotation of the handwheel drives the valve stem to rotate, which makes the gate lift. This kind of valve is called Rotary stem gate valve or NRS gate valve.