| Double Bleed-Block Special Valve |
Double Bleed-Block Special Valve |
Application：
Double bleed-block Special valve is applicable for cutting off the mediums on pipe of aviation gasoline, crude oil, light oil, nature gas, liquid petroleum gas, gas and chemicals.
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Feature
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① When the valve opened and closed, there is no contact between the sealing surfaces of body and slip slices. So there is no friction and wear-out on the sealing surfaces. The operating (open /close) torque is little and the service life of the valve is long.
② For maintenance and reparation, it is no need to remove the valve from pipe. Maintenance is very easy just to open the bottom gland of valve and change a pair of slip slices.
③ The body and cock is full bore. When the medium flows through valve, there is no flow resistance and the flow could clean the pipe so that it overcomes the shortcoming of the valve with reduced bore.
④ The inside of the body is plated with chrome and the sealing area is hard and smooth.
⑤ The elastic sealing of slip slices is made of fluoroelastomer and is died into the notch on slip slices. The metal–metal sealing with fire-proof function is the back of elastic sealing.
⑥ The valve has automatic bleeder device (optional) which could avoid the pressure in body chamber increase abnormally and check the effectiveness of the valve seal after completely closed valve.
⑦ The switch indicator is synchronous with positioner. It could exactly display the situation of valve action.
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Material of Main Parts
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| Body |
Slip slice |
Cock |
Stem |
Screw sleeve |
Seal ring |
Packing |
| WCB |
QT 500 |
WCB |
2Cr13 |
45 |
F luoroelastomer |
F lexible graphite |
| CF8 |
CF8 |
CF8 |
304 |
304 |
F luoroelastomer |
F lexible graphite |
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Standards and Specifications
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Design & Manufacture API16D
Face to Face Dimension ANSI B16.10
Type of Connection ANSI B16.5
Testing API598, API6D
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| Pressure Test |
| Class |
150Lb |
300Lb |
600Lb |
900Lb |
| Strength test |
3.0MPa |
7.5MPa |
15.0MPa |
22.5MPa |
| High pressure sealing test |
2.2MPa |
5.5MPa |
11.0MPa |
17.5MPa |
| Low pressure sealing test |
0.6MPa |
0.6MPa |
0.6MPa |
0.6MPa |
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Working Principle
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He working principle is the action of two slip slices on the cock. |
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| Closing valve |
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When closing valve, turn the handwheel, rotate the cock and slip slices for 90°.Then the cock moves down forward. With the cock moving, the slip slices are pressed towards the sealing of body chamber till the elastic seal ring is pressed on the bore both top and bottom ends so that forming sealing. |
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| Opening valve |
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When opening valve, turn the handwheel, lift the cock and draw the slip slice from both sides of body sealing surfaces. When the slip slice separates from body sealing surfaces, continue turning handwheel, rotate the cock and slip slices for 90°. Then valve is at opening position.
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| About sealing |
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The elastic sealing is died into the notch on the slip slices. With slip slice moving, the seal ring is pressed gradually into the notch. The metal–metal sealing between slip slices and body bore avoid elastic seal ring be pressed continuously and has fire-proof function.
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| Double bleed-block function |
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Double bleed-block function is completely blocking the pipe both sides, using 2 block valves and another bleed valve in the middle of 2 block valves. Closing 2 block valves and opening bleed valve could improve system safety. If the first block valve leaks, the leaking medium could be drawn off through the opened bleed valve.
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| Double sealing |
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Two independent slip slices are pressed towards both sides of body bore (double blocking). When the valves closing, the bleed valve is open to check the effectiveness of the valve seal (bleeding).
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| Material List of Main Parts |
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| No. |
Name of Part |
Material |
No. |
Name of Part |
Material |
| 1 |
Body |
WCB |
12 |
Bolt |
35# |
| 2 |
Bottom gland |
WCB |
13 |
Yoke |
WCB |
| 3 |
plug |
35# |
14 |
Bolt |
35# |
| 4 |
Slip slice |
QT500-7 |
15 |
Operating device |
discreteness |
| 5 |
Cock |
WCB |
16 |
Indication bar |
1Cr13 |
| 6 |
Bonnet |
WCB |
17 |
Indicator |
ZL104 |
| 7 |
Bolt |
35# |
18 |
Pin |
65Mn |
| 8 |
Nut |
45# |
19 |
Dust wiper |
PVC |
| 9 |
Packing |
lexible graphite |
20 |
O ring |
F luoroelastomer |
| 10 |
Bolt |
35# |
21 |
O ring |
F luoroelastomer |
| 11 |
Packing gland |
WCB |
22 |
O ring |
F luoroelastomer |
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| Performance Parameter |
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| Performance Parameter |
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| Performance Parameter |
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| Performance Parameter |
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