Is the use of the control valve gas valve opening and closing parts of the body opening to

regulate the flow of media , the media pressure reduced, while the role of back pressure

valve with adjustable opening and closing parts of the opening , so that the valve after

the pressure was maintained at a certain range, and the valve body or the valve sprayed

into the cooling water, and the lower the temperature of the media , such valves as

pressure temperature relief valve .
The valve characteristics, is in the inlet pressure to changing circumstances , to maintain

the gas valve outlet to listen to pressure and temperature values ​​within a certain range,

the valve in the pipeline in this category generally should be installed horizontally.
This series belongs to the pilot valve piston valve . From the main valve and pilot valve

two parts. Mainly by the main valve seat , the main valve plate , piston, springs and other

parts. Mainly by the pilot valve seat , valve , diaphragm, spring, adjusting springs and

other parts. By adjusting the outlet pressure adjusting spring pressure setting , the use

of outlet pressure sensing diaphragm , the drive piston through the guide opening and

closing the valve adjust the main throttle valve flow area size of the parts to achieve the

pressure regulator function .
This product is mainly used for gas piping, such as air , nitrogen, oxygen , hydrogen,

liquefied petroleum gas, natural gas and other gases.
Form of the structure can be divided into the film , spring diaphragm , piston , lever and

bellows ; according to the number of seats can be artificially single -block and two-seater

; press the valve can be divided into different positions and is acting reaction type .
By the use of the media can be divided into steam valve , air valve, gas valve and so on.
Direct acting pressure reducing valve
Compressed air pressure is P1 , the left input port 10 through the throttle valve , the

pressure drop P2 output. The size of P2 adjusted by adjusting spring 2,3 . Turn the knob

clockwise 1 , 2, 3 and diaphragm compression spring 5 spool 8 down , increasing the degree

of opening of the valve port 10 so that P2 increases. When knob 1 is rotated

counterclockwise , the opening degree of the valve port 10 is decreased , P2 decreases .

If the transient elevated P1 , P2 will subsequently increases, so that the diaphragm

pressure chamber 6 increases , the thrust force generated on the diaphragm 5 increases

accordingly , this thrust force destroyed the original balance of the diaphragm 5 up

movement , a small part of the flow through the overflow hole 12 , the discharge vent 11 .

While the diaphragm moves , because the role of the return spring 9 , the valve body 8 is

moved upward, turn it into the valve port 10 , to increase the throttling effect , the

output pressure decreases until a new equilibrium until the output pressure of basic went

back to the original values. If you enter the instantaneous pressure drop , the output

pressure also drops , the diaphragm 5 down, then down the spool 8 , the intake valve port

10 open big, throttling effect decreases, so that the output pressure is basically back to

the original values. Rotate the knob counterclockwise one . 3 the adjusting spring

relaxation , the gas acts on the membrane 5 is greater than the thrust force of the spring

regulating the diaphragm upward curved , by the action of the return spring closing the

intake valve port 10 . Then rotate the knob one , the top of the intake valve 8 , Block 4

will disengage with the relief valve diaphragm chamber 6 will air through the overflow hole

12 , the discharge vent 11 so that the valve is no output state .

Pilot type valve
When the valve output pressure higher or larger diameter , the use of direct pressure

regulator pressure regulator spring , the spring stiffness necessarily too large, flow

changes , the output pressure fluctuations, the valve structure size will increase. To

overcome these shortcomings, and pilot type valve . Pilot valve works with direct-acting

basically the same. Pilot gas valve regulator used is determined by the small direct-acting

valve supply . If the small direct acting pressure reducing valve mounted on the valve body

, it is called an internal pilot type valve ; If small direct acting pressure reducing

valve installed in the main body outside , then called external pilot type valve . Compared

with the direct acting pressure reducing valve , the valve is increased by the nozzle 4 ,

baffles fixed orifice 9 and the gas chamber B is composed nozzle flapper enlarge link. When

the distance between the nozzle and baffle small changes , it will cause the pressure in

chamber B root significant changes occur , thereby causing the diaphragm 10 has a large

displacement , to control the vertical movement of the spool 6 , the inlet valve port 8 to

open large or off small, increases the sensitivity control on the spool , which improves

the regulation accuracy .
Setpoint control
Setting a high-precision valve is mainly used in pressure value . There are currently two

specifications setpoint pressure control: the gas supply pressure was 0.14MPa and 0.35MPa,

output pressure ranges of 0 and a 0-0.1MPa 0.25MPa. Its output pressure fluctuation is less

than 1% of the maximum output pressure , commonly used in the required supply air pressure

and precise signal pressure of the occasion, such as pneumatic laboratory equipment,

pneumatic automatic devices.
Since setting utilizes the output pressure and nozzle baffle feedback control of the main

valve amplification , making it less able to respond to changes in pressure , so that the

output pressure has been timely in order to maintain the basic stability of the outlet

pressure , namely setting regulation accuracy is higher.
Value is in non- working condition, compressed air from the air source input through the

filter a filtered into the room and A 's wife . Main spool 19 and supply pressure of the

spring 20 under the action of pressure on the seat , so that A and B Room Room

disconnected. A gas flow into the chamber via a valve port ( also known as valve ) 12 to F,

and then through the step-down constant orifice 13 , Room G and D , respectively, into the

room. As time has yet to patch 8 afterburner , baffles 5 and larger spacing between the

nozzle 4 , the gas flow from the nozzle 4 less resistance when airflow , G and D on the

lower pressure chamber , the diaphragm 3, and 15 to maintain its original position. Only

trace gases into the chamber through the main chamber through the valve port B 2 from the

exhaust vent ; another part from the output port emptying. At this point no airflow output

of the output port , emptying from the nozzle outflow trace gas nozzle flapper device is to

maintain the necessary work , because it is a reactive gas consumption , so I hope its

consumption as small as possible .
Value is in working condition, turn the handle 7 , pressing the diaphragm spring 6 and 8

push down together with the flap 5 , flap 5 and the narrow pitch of the nozzle 4 , the air

resistance increases, the chamber G, and D pressure rise. Chamber pressure diaphragm 16 in

the D down under the action of the valve port 2 closed, and push the main valve 19 to open

the valve port , compressed air through the chamber B, and H from the output port . At the

same time , H chamber pressure rises to the diaphragm 8 and the feedback , the feedback

suffered when the diaphragm 8 and the spring force of the force balance , the fixed value

is a gas under pressure is output . When the input pressure fluctuations, such as pressure

rises , B and H chamber pressure chamber transient increased, so that the diaphragm 8 on

the move, resulting baffle 5 and increase the spacing between the nozzle 4 , G and D

chamber chamber pressure drops . Since increased pressure chamber B , D chamber pressure

drops , the diaphragm 15 is moved upward under the action of pressure , the main valve port

is reduced, the output pressure decreases until stabilized to the set pressure . In

addition, the input pressure increases , E and F, chamber pressure transient pressure also

rises , the diaphragm 3 under the action of the upper and lower pressure on the move, off a

small regulator valve port 12. Since throttling strengthen , F chamber pressure drops , and

always maintain the differential pressure across the orifice 13 is constant, so through the

orifice 13 of the gas flow constant, so that the nozzle plate sensitivity is improved. When

the input pressure decreases , B and H chamber pressure chamber instantaneous drop ,

together with the diaphragm 8 baffle 5 due to the destruction of the force balance down,

the nozzle 4 with baffle 5 spacing decreases , G and D chamber chamber pressure rise ,

diaphragm 3 and 15 down . Diaphragm 15 downward so that the main valve opening increased,

Room B & H, the chamber pressure rise until the set pressure balance so far. The diaphragm

3 down, allowing the regulator to port 12 open big , F chamber pressure rise , and always

maintain a constant differential pressure across the orifice 13 is constant. Similarly ,

when the output pressure fluctuation when the pressure fluctuation of the input obtained

when the same adjustment.
Pressure range
It refers to the valve output pressure P2 adjustable range , in this range required to

achieve the required accuracy. Pressure range regulator spring stiffness mainly related .
Pressure characteristics
It refers to the flow of g is constant , because the input pressure fluctuations caused by

pressure fluctuations in the output characteristics . Output pressure fluctuation is

smaller, the better the valve characteristics . Output pressure must be less than the input

pressure - it does not substantially set value changes with the input pressure .

Flow characteristics
It refers to the input pressure - time , the output pressure with output flow g and change the hold of . G When the flow changes , the output pressure changes as small as possible . Usually the lower the output pressure , which changes with fluctuations in the output flow is smaller.
Gas valve installation and maintenance should note the following:
1 , in order to facilitate the operation and maintenance of the valve is usually installed upright in horizontal pipelines .
2 , the installation should pay attention to the direction of the arrow shown on the valve body and the pipeline flow of medium consistency .
3, in order to prevent overpressure valve , should be less than 4M away from the valve outlet to install a pressure reducing valve .