Design of Small-diameter Supercritical Fully Forged Gate Valves
Dec 29, 2022
Design parameters and main materials of small-diameter supercritical fully forged gate valves are as follows:
Working temperatures: 369°C
Working pressure: 313MPa
Nominal diameter: DN 150
Matching pipes: 219 to 35
The valve is mainly used in the secondary desuperheating water main pipeline of the superheater to cut off the medium. The materials of the main parts are shown in Table 1.
Table 1 Materials of main parts
Working temperatures: 369°C
Working pressure: 313MPa
Nominal diameter: DN 150
Matching pipes: 219 to 35
The valve is mainly used in the secondary desuperheating water main pipeline of the superheater to cut off the medium. The materials of the main parts are shown in Table 1.
Table 1 Materials of main parts
| Components | Materials |
| Valve bodies | A105 |
| Discs | 25 |
| Packing rooms | 25 |
| Stems | 38CrMoA1A |
| Column | 35 |
| Seats | A105 |
Calculation
This forged valve adopts ASME B16.34 SPL "Flanged, threaded and welded valves". The main design calculations include the following:
- The thickness of the valve body
- The total force and specific pressure on the sealing surface
- Calculation of the strength of the valve stem
- Stability of the valve stem
- Calculation of the strength of the valve seat and disc
- Calculation of the strength of the valve packing room
- Calculation of stress of the top edge of the valve body
- Calculation of strength of quarter rings
- Calculation of the shear force of the disc guide rib
- Calculation of total torques
- Calculation of strength of stem nuts and screws
- Calculation of strength of bolts connected to pillar
- Calculation of strength of packing glands and pressure plates
Conclusion
This small-diameter supercritical fully forged gate valve is a product of a 600 Mw unit. At present, most of the gate valves developed and designed in China are castings. There are many casting defects, resulting in a large number of welding repairs on the valve body, and even some defects are gradually exposed during the operation project, which brings a severe test to the hydrostatic test and safe operation of the unit. The use of fully forged gate valves can avoid problems caused by casting defects, and is also the development trend of gate valves for high-parameter and high-performance units. Although forged gate valves are more expensive than casting valves, they have a good guarantee for the safe operation of the unit, and save the cost of welding repairs and maintenance, once and for all.
Next: The Sealing of Fully Welded Forged Ball Valves for Natural Gas Pipelines (Part one)
Previous: Working Principles & Structural Characteristics of Supercritical Forged Gate Valves
News
About Us
Best Categories
Useful Links