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    2. External dimension, flange dimension and bolt hole dimension of telescopic butterfly valve

      Column:Technology Frontier Time:2019-08-23

      Expansion butterfly valve, as a component used to realize on-off and flow control of pipeline system, has been widely used in many fields such as petroleum, chemical industry, metallurgy, hydropower and so on. The butterfly plate of the telescopic butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical channel of the butterfly valve body, the disc butterfly plate rotates around the axis, and the rotation angle is between 0 ~90 and when the rotation angle is between 0 and 90 the self-operated valve is fully open. This valve is generally installed horizontally.

      Structural characteristics of telescopic butterfly valve:

      The expansion butterfly valve has the characteristics of simple structure, small volume, light weight, low material consumption, small installation size, switching rapidly, 90 degree reciprocating rotation, small driving moment, etc. It is used to cut off, connect and regulate the medium in the pipeline, and has good fluid control characteristics and sealing performance. When the expansion butterfly valve is in full open position, the thickness of the expansion 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 better flow control characteristics. The expansion butterfly valve has elastic seal and metal seal. Elastic sealing valve, sealing ring can be embedded in the valve body or attached to the butterfly plate.

      Metal-sealed telescopic butterfly valves generally have longer life than elastic-sealed valves, but it is difficult to achieve complete sealing. Metal seal can adapt to higher working temperature, while elastic seal has the defect of temperature limitation. If the expansion butterfly valve is required to be used as flow control, the main thing is to correctly select the size and type of the valve. The structure principle of telescopic butterfly valve is especially suitable for making large caliber valves. Telescopic butterfly valves are not only widely used in petroleum, gas, chemical industry, water treatment and other general industries, but also used in the cooling water system of thermal power plants.

      The commonly used telescopic butterfly valves are butterfly valves with pair clamps, manual flanged telescopic butterfly valves and butt welded butterfly valves. The butterfly valve is connected between two pipeline flanges by double-head bolts; the flanged butterfly valve is connected with flanges on the valve, and the flanges on both ends of the valve are connected with pipeline flanges by bolts; the two ends of butterfly valve are welded with pipeline flanges. The streamlined design of butterfly plate can reduce the loss of fluid resistance, so it is an energy-saving product. The valve stem is a through-rod structure. After quenching and tempering treatment, it has good comprehensive mechanical properties, corrosion resistance and scratch resistance. When the butterfly valve is opened and closed, the stem is only rotated but not lifted. The filler of the stem is not easy to destroy and the seal is reliable. Fixed with the butterfly plate cone pin, the extension end is anti-washout design, so as to avoid the valve stem collapse when the connection between the stem and the butterfly plate accidentally breaks.

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

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

      3. Flow characteristic tends to straight line and has good regulation performance.

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

      5. Seals can be replaced, and the seals are reliable to achieve bidirectional seals.

      6. The butterfly plate can be sprayed with coating according to user's requirements, such as nylon or PTFE.

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

      8. The driving mode can be manual, electric or pneumatic.

      Standard for use of telescopic butterfly valves

      Design criteria: GB/T12238-1989

      Flange connection dimensions: 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

      Expansion butterfly valve is a kind of valve which uses circular butterfly plate as opening and closing parts and rotates with the 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 passage of the telescopic butterfly valve body, the disc butterfly plate rotates around the axis, and the rotation angle is between 0 ~90. When the rotation angle is between 0 ~90, the valve is fully open.


       image.png

      Structural diagram of telescopic butterfly valve

      Main technical parameters of telescopic butterfly valve:


      Nominal diameter

      DN(mm)

      50~2000

      Nominal pressure

      PN(MPa)

      0.6

      1.0

      1.6

      Test pressure

      strength test

      0.9

      1.5

      2.4

      Sealing test

      0.66

      1.1

      1.76

      Gas seal test

      0.6

      0.6

      0.6

      Applicable temperature

      ≤80℃

      Applicable medium

      Air, water, steam, gas, oil, etc.

      Driving form

      Manual, worm and worm gear transmission, pneumatic transmission, electric transmission.

       

      Material of main parts of telescopic butterfly valve

      Part name

      Material Science

      valve body

      Cast iron, cast steel, stainless steel, chromium-molybdenum steel, alloy steel

      Disc

      Cast steel, alloy steel, stainless steel, chromium-molybdenum steel

      Seal ring

      Rubber, PTFE, Polylactone, Stainless Steel

      Stem

      2Cr13, stainless steel, chromium-molybdenum steel

      Telescopic tube

      Cast iron, cast steel, stainless steel, chromium-molybdenum steel

      filler

      Flexible graphite

       

      External dimension, flange dimension and bolt hole dimension of telescopic butterfly valve


      Nominal path

      Shape size (reference value)

      Flange size and bolt hole size (standard value)

      H

      H1

      Design Maximum Length

      Design Minimum Length

      Design Length

      A

      B

      0.6MPa

      1.0MPa

      1.6MPa

      millimeter

      D

      D1

      D2

      n-d

      D

      D1

      D2

      n-d

      D

      D1

      D2

      n-d

      50

      80

      309

      186

      156

      171

      180

      200

      140

      110

      88

      4-14

      165

      125

      99

      4-18

      165

      125

      99

      4-18

      65

      95

      337

      190

      160

      175

      180

      200

      160

      130

      108

      4-14

      185

      145

      118

      4-18

      185

      145

      118

      4-18

      80

      98

      347

      198

      166

      182

      180

      200

      190

      150

      124

      4-18

      200

      160

      132

      8-18

      200

      160

      132

      8-18

      100

      114

      373

      228

      188

      208

      180

      200

      210

      170

      144

      4-18

      220

      180

      156

      8-18

      220

      180

      156

      8-18

      125

      128

      405

      240

      201

      220

      180

      200

      240

      200

      174

      8-18

      250

      210

      184

      8-18

      250




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