Telescopic Butterfly Valve Size, Flange Size And Bolt Hole Size

- Jul 03, 2020-

The telescopic butterfly valve has been widely used in many fields such as petroleum, chemical industry, metallurgy, hydropower, etc. The butterfly plate of the telescopic butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical passage of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, and the rotation angle is between 0° and 90°. When it rotates to 90°, the self-operated valve is fully opened. This valve is generally installed horizontally.


Structural characteristics of telescopic butterfly valve:


The telescopic butterfly valve has the characteristics of simple structure, small size, light weight, low material consumption, small installation size, rapid switching, 90° reciprocating rotation, and small driving torque. It is used to cut off, connect, and adjust the medium in the pipeline. Good fluid control characteristics and sealing performance. When the telescopic butterfly valve is in the fully open position, the thickness of the telescopic butterfly valve is the only resistance when the medium flows through the valve body, so the pressure drop generated by the valve is very small, so it has good flow control characteristics. There are two types of telescopic butterfly valve: elastic seal and metal seal. Elastic sealing valve, the sealing ring can be embedded on the valve body or attached to the periphery of the butterfly plate.


Telescopic butterfly valves with metal seals generally have a longer life than elastic seals, but it is difficult to achieve complete sealing. Metal seals can adapt to higher operating temperatures, while elastic seals have the disadvantage of being limited by temperature. If the telescopic butterfly valve is required to be used as a flow control, the main thing is to choose the valve size and type correctly. The structural principle of the telescopic butterfly valve is especially suitable for making large-diameter valves. Telescopic butterfly valves are not only widely used in general industries such as petroleum, gas, chemical, and water treatment, but also in cooling water systems of thermal power stations.


Commonly used telescopic butterfly valves include wafer-type butterfly valves, manual flange-type telescopic butterfly valves, and butt-welded butterfly valves. Wafer type butterfly valve is to connect the valve between the two pipeline flanges with stud bolts; flange type butterfly valve is to have a flange on the valve, and use bolts to connect the flanges on both ends of the valve to the pipeline flange; butt welding Both ends of the butterfly valve are welded to the pipeline. The streamlined design of the butterfly plate makes the fluid resistance loss small, which can be described as an energy-saving product. The valve stem is a through-rod structure, after quenching and tempering, it has good comprehensive mechanical properties, corrosion resistance and scratch resistance. When the butterfly valve is opened and closed, the valve stem only rotates and does not move up and down. The packing of the valve stem is not easy to damage and the seal is reliable. It is fixed with the taper pin of the butterfly plate, and the outgoing end is designed to prevent the outgoing type, so as to prevent the valve rod from collapsing when the connection between the valve rod and the butterfly plate is accidentally broken.


1. Small and light, easy to disassemble and maintain, and can be installed at any position.

2. The structure is simple and compact, the operation torque is small, and the 90-degree rotation is quickly opened.

3. The flow characteristics tend to be straight and the adjustment performance is good.

4. The connection between the butterfly plate and the valve stem adopts a pinless structure, which overcomes the possible internal leakage points.

5. The seal can be replaced, and the seal is reliable to achieve two-way sealing. 

6. The butterfly plate can be spray coated according to user requirements, such as nylon or PTFE.

7. The valve can be designed as flange connection and wafer connection.

8. The drive mode can be selected from manual, electric or pneumatic.

Telescopic butterfly valve adopts standard

Design standard: GB/T12238-1989

Flange connection size: GB/T9113.1-2000; GB/T9113.2-2000

GB/T9115.1-2000; GB/T9115.2-2000

Pressure test: GB/T13927-1992; JB/T9092-1999

Working principle of telescopic butterfly valve

The telescopic butterfly valve is a valve that uses a circular butterfly plate as an opening and closing member and rotates with the valve stem to open, close, and adjust the fluid passage. The butterfly plate of the telescopic butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical channel of the valve body of the telescopic butterfly valve, the disc-shaped butterfly plate rotates around the axis, the rotation angle is between 0° and 90°, and when it is rotated to 90°, the valve is fully open.

Butterfly-valve