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Jiaxing Expert mechanical technology co. LTD

Extraction check valve

  • Pneumatic extraction check valve / hydraulic extraction check valve
  • Pneumatic extraction check valve / hydraulic extraction check valve
  • Pneumatic extraction check valve / hydraulic extraction check valve
  • Pneumatic extraction check valve / hydraulic extraction check valve
  • Pneumatic extraction check valve / hydraulic extraction check valve
  • Pneumatic extraction check valve / hydraulic extraction check valve

1,introduction  

Extraction system is the use of steam in the steam turbine has done part of the work, the introduction of regenerative heaters to heat boiler feed water, improve plant thermal benefits. At the steam outlet are equipped with a quick shutdown of the electric isolation valve and check valve each one. Before the electric isolation valve is placed on the check valve, the check valve acts as an overspeed protection to prevent the turbine from sudden load shedding. It also serves as the first protection to prevent the turbine from entering the water. The isolation valve serves as the first level of protection for the turbine inlet water.

Pumping check valve control not through the air blocking valve, but by the electromagnetic valve to intercept the solenoid valve signal from the DCS leads. The valve is equipped with a cylinder or cylinder actuator mounted on the side of the valve and connected to the valve disc by a movable connecting rod. The cylinder or cylinder acts as a single action. When the valve is open with air pressure or oil pressure, the spring closes the valve when pressure is lost. The device can reliably ensure the quick closing of the suction check valve within 1 s, and provide all the accessories according to the system control requirements, such as the solenoid valve, the travel switch and the like.

The control system of the extraction check valve is the power control center of the extraction check valve in each section of the turbine. According to the requirements of the unit, different given signals are input to the solenoid valves in the system to control the working states of the corresponding check valves so as to meet the requirements of the unit The needs of various conditions. Pneumatic actuators using compressed air 0.6MPa pressure as the power source, with a simple structure, easy to establish a source of air, pollution-free and so on.

When receiving the check valve open signal, the solenoid valve on the pipeline action, pressure or oil pressure into the corresponding check valve actuator chamber, the check valve disc in a free state, the role of the positive flow Under the check valve open.

If the load of the steam turbine or the main steam valve is closed, when the check valve closing signal is received, the electromagnetic valve on each pipe will act to cut off the air pressure or oil pressure of the actuator. The check valve will close by the force of the spring.

2,model description

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3,main implementation of standards

1, the valve standard: GB / T12236-2008 "steel, chemical and related industrial swing check valve"

2, pressure test and seal test standards: GB / T26480

3, casting technical requirements by: GB12229

4, flange standard: according to user requirements

4,main performance parameters


Technical characteristics

 1

The valve is pure reverse type, combined with the globe valve, steam exhaust pipe in the exhaust form a complete protection of the turbine

 2

Close with weight off hydraulically assisted closure, dual closure structure to reduce the weight of the valve to reduce pressure loss, shut down more reliable

 3

Low pressure loss coefficient

 4

Wear-resistant valve shaft design

 5

Valve top of the installation structure, eliminating the need to remove the valve replacement valve difficulties

 6

1Cr13/ stellite 6 The solid seal is welded to the body

 7

Leak rate≤3DN/25 mL/min JB/T9092-1999

 8

Lower operating torque and easy maintenance

Valve material

1

Body

≤400°C   WCB

≤540°C   C5

2

Seat / bonnet / disc / rocker

≤400°C   WCB

≤540°C   C5

3

Welding ring

1Cr13/ stellite 6

4

Valve shaft

35CrMoA GB/t3077

5

Sealed packing

PS-799(Flexible graphite)

6

Sleeve

1Cr18Ni9Ti GB2598

Hydraulic actuator

1

Features

Liquid spring off

2

Imported oil

G1/2”

3

Back to the mouth

G1”

4

Limit switch

According to user requirements with or without explosion-proof




Pneumatic actuator

1

Features

Gas open the spring off

2

Air inlet

Tubeφ18×3

3

Travel switch

According to user requirements with or without explosion-proof

4

Solenoid valve power

According to user requirements