Quick Crossover Safety (Relief) Valve (GAKH)

Quick Crossover Safety (Relief) Valve Introduction
Quick Crossover Safety((Relief) Valve is a further developped and improved Double Port Safety Valve. It mainly composed two spring loaded double port safety valves, a switching mechanism and a Y Shaped Pipe. The valve inlet is at the bottom of the Y Shaped Pipe. By rotating the Handwheel of the Switching mechanism, one safety valve will open, and the other one will close. These two valves may work by turns. According to the working medium, temperature and pressure,the switching mechanism may be equipped with various types of safety valves so as to adapt the various working condition. The connecting dimension of Flanges may selected according to clients' request.

Quick Crossover Safety (Relief) Valve Application
Working Medium: Gas, Liquid
Sizes: 1"-10"
PN: Class 150LB-600LB.
Applicable Temperature: -196°C~-540°C

 

Product Description

I. Summarize:
Double interlocking switch safety device is a new product independently developed by

Luofu based on the original safety valve and changeover valve. According to the

design of API520 and BS1873, the inlet and outlet of the safety valve on the pipeline

can be switched jointly, allowing for simultaneous opening and closing. This

instruction primarily introduces the changeover valve. About the safety valve, please

refer to our Operating Instructions for Spring Type Safety Valve.

II. Use & Performance Specification

2.1. Use: The product is widely applied as an overpressure protection device on the

corrosive medium and non-corrosive medium pipelines such as water, oil, natural gas

and steam. It has the advantages of small flow resistance, flexible opening/closing,

long service life, superior safety and reliability and compact structure, it is able to achieve
following functions:
 

<1. Non-stop operation. While one safety valve is operating, the other can be

taked down for maintenance on the premise of non-stop operation so as

to achieve the maximum economic profits due to reduce the shutdown

period.
 

<2. Two safety valves share one pipeline, which can reduce both the pipeline

number and cost.
 

<3. The inlet and outlet changeover valve of the safety valve are allowed for

synchronous operation as well as simultaneous opening/closing, making

the operation more easily and reliably.
 

2.2. Scopes of application: chemical industry, petroleum refining, oil and natural

gas pipeline transportation, etc.

2.3. Performance standard (changeover valve):

Pressure Grade(Lb)	Normal temperature test pressure (MPa)			Applicable temperature (ºC)	Applicable media
	Shell	Pressurization and upper seal	Low pressure seal
150	3.0	2.2	0.6	-29~300	Water,gas, oil
300	7.5	5.5	0.6	-29~300	Water,gas, oil

2.4. Maximum working pressure rating of valve (pressure-temperature standard ) (gauge pressure: MPa)

Valve body material WCB:

Temperature (ºC)	-29~38	100	300
Rating Value	1.96	1.77	1.02
Rating Value	5.11	4.66	3.98

 
Valve body material CF8:

Temperature (ºC)	-29~38	100	300
Rating Value	1.90	1.57	1.02
Rating Value	4.96	4.09	3.09

Note: The temperature in the table above refers to the temperature of the pipeline media under working

condition. The pressure in the table is a sustained non-impact pressure.

III. Main Standards:

3.1. The design and manufacture is in accordance with API 520 and BS 1873;
3.2. The flange connection is in accordance with ASME B16.5;
3.3. The inspection and test is in accordancewith API 527 and API 598;
3.4. The pressure-temperature standard is in accordance with ASME B16.34.

 

IV. Demonstration of the type (changeover valve):

GAKH-150C

GAKH--Goole Changeover Valve;
150--Nominal pressure is 150Lb;
C--Material of valve is carbon steel.

V. Structural features:
5.1. Device Structure:

1. Bottom reducing joint	2. Inlet changeover valve	3. Inlet reducing joint
4. Outlet changeover valve	5. Safety valveI	6. Safety valveII
7. Chain	Â	Â

5.2. Structure of changeover valve:

1. Valve body	2. Valve clack	3. Valve stem
4. Valve deck	5. Packing	6. Packing bushing
7. Valve stem nut	8. Valve bearing	9. Chain wheel
10. handle wheel	11.Anti-rotation screw	12. Plug Screw

5.3. The changeover valve adopts three-way structure.
5.4. The changeover valve body is connected with valve deck by MFM flange.
5.5. The changeover valve is connected with pipeline by RF flange.
5.6. Planar seal is used for the changeover valve clack.

VI.Working principles:

The handle wheel and chain wheel of the changeover valves located at inlet and

outlet are all installed on the valve stem nut. The handle wheel, chain wheel and valve

stem nut will rotate together. There is a chain located between two chain wheels

through the chain, the two changeover valves and valve stem nuts will rotate at the

same time. Through the trapezoidal nut, the valve stem nut will drive the valve rod to

move up and down then the valve rod drives the valve clack so that two changeover

valve will act synchronously, allowing for simultaneous opening and closing.

As the figure shows, the changeover valve is designed with two sealing surface,

allowing one closing while the other opening. Rotating the handle wheel clockwise and

the valve clack will move far away from it so that the sealing surface which is far from

the handle wheel will be closed while the nearby one will be open. In that way, the

inlet and outlet changeover valve of the safety valve which are close to the handle will

be open so as to play a protection role, while the inlet and outlet changeover valve of

the safety valve far away from the handle will be closed, taking no effects and can be

able to disassembled for maintenance. Otherwise, rotating the handle counterclockwise

and the valve clack will move close to the handle wheel so that the sealing surface

which is close to it will be closed while the distant one will be opened. In that way, the

inlet and outlet changeover valve of the safety valve which is far away from the handle

will be opened so as to play a protection role, while the changeover valves of the safety

valve at inlet and outlet which is close to the handle wheel will be closed, taking no

effects and can be able to disassembled for maintenance.