Double seat globe valve
key word：Heat exchange element
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Product description
Double seat globe valve
1. Introduction
1.1. Purpose
By changing the width, depth and number of parallel ring grooves, the double seat stop valve can meet the needs of different flow characteristics. It is generally used in the hot steam drainage of power plant, the main fixed discharge valve of boiler, the regular discharge valve of boiler and other occasions.
1.2. Model meaning
J**##@@-&&$$/※※
J --- stop valve code
**----Structure type code (see table 37-1)
##-----D means electric; Q means steam; s means manual
@@-------Valve seat sealing surface or lining material code (see table 37-2)
&&----------Nominal pressure (MPA)
$$-------Material of valve body
※※------Nominal diameter (mm)
Table 37-1 structure code of stop valve
| structural style | Turn off type | Ring groove type | Double seat | Tee type | Special type |
| Code | 1 | 2 | 3 | 5 | 6 |
Table 37-2 valve seat sealing surface or lining material code
| Seat sealing surface or lining material | Codel |
| Copper alloy | T |
| Rubber | X |
| Nylon plastic | N |
| The alloy steel is acid resistant or non-corrosive | H |
| Fluoroplastics | F |
| Tin base bearing alloy (Babbit) | B |
| Nitriding steel | D |
| Boronizing steel | P |
| Cemented carbide | Y |
| Rubber lining | J |
| Lead lining | Q |
1.3. Structural features
The double annular groove structure can effectively reduce the erosion of the valve seat. The upper water inlet mode makes the valve close with a downward force, so as to make the seal more reliable. Self sealing structure can adapt to high temperature and high pressure difference. The sealing surface of the valve seat is made of stainless steel, and stellite alloy is overlaid on the sleeve seat, and then the sleeve seat is welded with the valve body. The sealing transition layer is good, the welding heat treatment can be well controlled, the service life is long, and the forged valve body has no impurities and pores.
2. Main technical parameters and product appearance
2.1. Main technical parameters (see table 37-3)
Table 37-3 main technical parameters of J series stop valve
| Item | Parameter |
| Nominal pressure（MPa） | 0～75（4500 Poung grade） |
| Nominal diameter (mm) | 20～500 |
| Applicable units | 50～1000MW units |
| Rated flow (t/h) | 0～3600 |
| Working temperature（℃） | ≤620 |
| Working medium | Water, steam, corrosive medium |
| characteristic curve | Linear, equal percentage, corrected equal percentage or other |
| Connection form of inlet and outlet | Flange connection or butt welding connection |
| Supporting actuator | Electric, pneumatic or other |
2.2. Product appearance (see figure 37-1)
3. Selection method
Generally, the selection of valves can refer to the recommended valve structure and type to determine the main technical conditions of the valve. According to the regulation requirements and the working temperature, pressure, density, noise and other conditions of the medium, not only the flow characteristics and flow coefficient should be considered For the inherent static characteristics of valves such as CV or KV, allowable pressure difference and regulation range R, the influence of the dynamic characteristics such as the distortion of flow characteristics caused by the changes of system resistance and operating conditions due to the different parallel and series positions of the valves installed on the actual pipeline must also be considered.
4. Scope of supply and general technical specifications
4.1. Scope of supply
It includes the valve body and the actuator matched with the valve. Other accessories, such as connecting pipe and reducing joint, are selected according to the requirements of users.
4.2. General technical specifications
Valve product design reference standard:
ASTM A182 / A182M-2008 Forged or rolled alloy steel nominal pipe flanges, forged pipe fittings, valves and parts for high temperature service
ASME B16.34-2004 Flanged, threaded and welded valves
ASME B16.10-2000 Valve structure length
ASTM A370-2003a Definite and test method for mechanical properties of steel products
ASTM A-388 / A 388M-2004 Standard Practice for ultrasonic inspection of heavy steel forgings
GB / T12224-2005 General requirements for steel valves
GB / T 10868-2005 Desuperheating and pressure reducing valve for power station
GB / T 13927-1992 General purpose valve pressure test
GB / T 5097-2005 Non destructive testing, penetrant testing and magnetic particle testing observation conditions
GB / T 19672-2005 Specification for pipeline valves
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