Parallel slide gate valve
key word：Heat exchange element
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Product description
Parallel slide gate valve
1. Introduction
1.1. Purpose
The parallel sliding gate valve has the advantages of simple structure and convenient operation. When it is used with pressure reducing device, it can be used in the minimum flow situation of feed water pump in power plant. In addition, it can also be used in other high pressure drainage systems.
1.2. Model meaning
Z**##$$-@@&&/※※
Z --- gate valve code
**-----Code of structural form (see table 40-1)
##-------D means electric; Q means steam; s means manual
$$- --- code of sealing surface or lining material of valve seat (see table 40-2)
@@------------Nominal pressure (MPA)
&&--------------Body material
※※------------Nominal diameter (mm)
Table 40-1 structural code of gate valve
| structural style | Wedge form | Parallel form | |||
| Elastic ram | Rigid single ram | Rigid double ram | Rigid single ram | Rigid double ram | |
| Code | 0 | 1 | 2 | 3 | 4 |
Table 40-2 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 |
Example: Z4DY-25 C / 80 refers to gate valve, the structure adopts parallel rigid double gate, electric actuator, the sealing surface of valve seat is cemented carbide, the pressure of valve is 25MPa, the material of valve body is carbon steel, and the nominal diameter of valve body is 80mm.
1.3. Structural features
1.3.1. Description of important parts. The valve core of parallel sliding gate valve adopts split structure, as shown in Figure 40 - 1.
In this structure, the valve core and the valve seat are in plane contact, when the valve core is under the pressure of the high pressure side, the up and down position can float in a certain range, the reliability of the seal is good, the requirements for the up and down position are not high, it is not necessary to apply too much push and pull on the valve stem, the working torque is small, the opening and closing speed is fast, and the erosion of the valve core and seat is small.
In addition, a spring is clamped in two different forms of circular valve plates. The two circular valve plates are relatively independent and can freely match with the valve seat. The pressure difference between the high and low pressure areas can provide enough pressure to make the valve have good self sealing performance. The higher the pressure difference is, the better the sealing performance of the valve is.
Under the action of high pressure difference, the valve core and the valve seat are closely connected, and the shear force generated when the valve core moves up and down can eliminate the garbage adhered on the valve seat, so as to reduce the wear of the valve core and the valve seat.
1.3.2. Important characteristics:
1.3.2.1. Two way flow, direct current structure
1.3.2.2. Two parallel sealing surfaces are sealed by the pressure difference on both sides of the valve. The higher the pressure difference is, the better the sealing performance is.
1.3.2.3. The valve stem does not bear thrust and the operating torque is small.
1.3.2.4. Not affected by thermal expansion
1.3.2.5. Parallel split spool, self adjust the parallelism with the valve seat
1.3.2.6. The valve core rubs the valve seat to remove impurities from the system
1.3.2.7. Hardfacing of sealing surface.
1.3.2.8. Diversion hole (Z961Y Series).
1.3.2.9. Self sealing bonnet (PN32)
2. Main technical parameters and product appearance
2.1. Main technical parameters (see table 40-3)
Table 40-3 main technical parameters of Z series parallel sliding gate 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 40-2)
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 interface pipe, reducing joint, etc. are selected according to the user's requirements.
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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