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Extraction steam check valve
Extraction quick close check valve is a special valve for the extraction system pipeline in thermal power plants to prevent the pressure in the steam turbine from suddenly decreasing when the load is suddenly turned off
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Application
The suction quick close check valve is a special valve for the steam extraction system pipeline in thermal power plants. It is used to prevent the steam turbine component from suddenly reducing the pressure in the steam turbine when the load is suddenly turned off. The steam in the extraction pipe and the heater flows back into the steam turbine causing the steam turbine blade to break and the malignant accident of destroying the steam turbine generator. In order to protect the safe operation of the steam turbine, the leakage of the heater system pipeline makes the water from the extraction pipeline into the steam turbine and the water hammer accident occurs. The extraction check valve can be closed in 0.5 seconds quickly and closely to ensure that when the water level of the feed heater is too high, the pneumatic device components receive the liquid countercurrent signal, and quickly separate the turbine, to maximize the protection of the turbine and the extraction system.
Characteristic
• The valve adopts swing type structure, casting body adopts streamline body design, the valve flow resistance is small;
• Body sealing face tilt 30°, reduce check valve closing time, ensure fast closing;
• The valve disc of the closing part is connected with the valve stem by rocker, and the valve disc is rotated around the valve stem, which can make the valve disc fall on the valve body sealing surface accurately and ensure the anastomosing of the sealing surface;
• A heavy hammer can be designed to balance the heavy torque of the disc assembly when the valve diameter is large. When the medium is flowing forward, it helps to open the check valve and keep the check valve stable during operation, reducing vibration;
• The side-mounted actuator is spring return single acting straight stroke pneumatic device or hydraulic device. The gas/hydraulic unit is installed on the left side by default (looking in the direction of airflow), if the user has special requirements, it should be indicated in the contract, and the gas/hydraulic unit can be installed on the right side.
Design Guides
| Design and manufacture | Pressure and temperature reference | Inspection and test |
| NB/T47044 | NB/ T47044 | NB/ T47044 |
| ASME B16.34 | ASME B16.34 | ASME B16.34 、MSS-SP-61 |
Product Range
| Nominal pressure | PN16～PN160（Class150—Class900） | |
| Nominal size | DN80～DN1000（NPS3～NPS 40） | |
| Body matenal | WCB 、WC6、WC9、ZG20CrMoV | |
| Test pressure(MPa) | Strength test (Water pressure) | 1.5×P(38℃ pressure rating) |
| Sealing test (Water pressure) | 1.1×P(38℃ pressure rating) | |
| Applicable Temperature | -29℃～575℃ | |
| Applicable medium | Steam, water | |
Note：
1、The valve beyond the above specifications can be customized according to user requirements;
2、The applicable temperature range of each valve shall be subject to the actual pressure bearing material of the valve.