Double Disc Gate Valve
- Used for the isolation of gases, especially in coke oven gas lines where tar content is very high. Ideal valve for isolation of highly toxic gas lines and gases with tar content.
- The valve mainly consists of the body, bonnet, disc, stuffing box, stem, superstructure, and drive mechanism.
- The actuator and bevel gearbox combination drives the stem nut of the bevel gearbox which is coupled with the valve stem and discs.
- This mechanism works like a screw jack and results in upward/downward movement of the disc resulting in open/close condition of valve.
- During valve operation, a centrally placed collapsible wedge (connected to the valve stem) exerts sealing force on discs while moving in downward/close direction and collapses in upward/open direction (avoids rubbing of seating surfaces while opening).
| 1. Size Range : | -400 to 3500mm |
| 2. Maximum Operating Pressure : | – Up to 0.3Mpa |
| 3. Maximum Operating Temperature : | – Up to 2500C |
| 4. Type of Sealing : | – Metal to Metal |
| 5. Connection to Pipeline : | – Flanged ends |
| 6. Installation in Pipeline : | – Vertical in horizontal pipeline |
| 7. Drive : | – Electric – Manual |
| 8. Testing : | – Body test – Seat leakage test – Operational test |
Special Features :
- The valve has a rising spindle and flexible wedge with an angular seat design.
- Metal-to-metal double sealing of hard-faced, machined, ground, and lapped seating surfaces achieves a high degree of isolation.
- Water can be filled between two discs of the valve to act as a water seal for 100% man-safe isolation.
- Steam purging arrangement for melting tar and drain ports for removal of molten tar and other trapped material.
- For high-pressure and large-size valves, a long stem nut arrangement can be provided.
