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Gas meter, regulator, valve installation considerations
3/22/2014 2:11:49 PM
Gas meter, regulator, valve installation considerations
Gas Meter
A gas flowmeter Category:
Volume of wet gas flowmeter
Dry film ( slide valve , piston )
Rotor ( Roots table )
Reasoning differential pressure ( plates, nozzles , Venturi )
Velocity ( turbo ) ( flat impeller , spiral impeller )
Vortex style
Second, the use of
1 , the use of film -type pressure is generally not more than 5kpa
Civil, public welfare users <100m3 / h
2 , Roots table
A, the pressure and flow > 100m3 / h
B, high precision, small gap between the rotor and the housing , fewer impurities , to install filtering devices
3 , Wet
A, suitable for low pressure flow rate measurement as a small laboratory
B, can also be used as third-class standard test used to measure gas flow device for household gas meter
4 , differential pressure
A, large flow , gas consumption changed slightly
B, higher cleanliness requirements
C, the temperature required for the metering process , the pressure correction and translation severe
5 , impeller
Used in natural gas
6 , vortex type
Vibratory flowmeter are fluid , it has no moving mechanical parts, large range , measure the volume of traffic when it is almost unaffected by fluid density, pressure, temperature , viscosity and other parameters , faster development.
Third, the film -type gas meter conditions of use
1 , clean coal , gas impurity content is not too high , should follow the " City Gas design specifications " requirement, if the impurity content is too high , it will affect the life and measurement accuracy of gas meters
2 , for low pressure gas pipe -line , apply pressure is generally not more than 5kpa
3, the temperature is generally within the range of claim 0-35 oC, if the temperature is below freezing , freezing the gas in the water condensate , will affect the normal use of the gas meter , when the use of liquefied petroleum gas, a temperature not lower than the dew point temperature.
Fourth, the installation conditions
1, the number of installations
A, each resident piped gas users should set up a separate metering device , just install a gas meter ; civil centralized metering device should be used to display.
B, the public welfare users should at least install a gas meter at each billing unit , such as billing unit is not the same , can be mounted points table
2 , environmental requirements
A, gas meter should be installed in the air temperature is not lower than 0 oC in dry, well ventilated , and easy look-up and maintenance of premises ( film table )
B, prohibited the gas meter installed in bedrooms, bathrooms , steam boiler room, dangerous goods and flammable storage place , and a place similar to the above .
C, Fortune Industrial users of public gas meter should be installed in a separate room.
D, IC card table because there are inheritance circuit board , can not be installed in damp , rain and sun areas.
3, the gas meter itself Conditions
A, factory certification
B, look no obvious damage
C, from the Ministry of factory calibration date more than six months
V. Installation
( A ) mounting height
1 , the flow = 3m3 / h China users
A, high table from the ground = 1.8
B, median tables 1.4-1.7 m from the ground
C, low table is 0.1 meters from the ground
Residents user traffic school table table should be appropriate. When multi-table hanging on the same wall , spacing between tables should be large
0.15 m , should generally be left in front of the table space is not less than 1 m .
2, the flow 3-5 m 3 / h film sheet can be installed on the ground type , can be mounted on a wall. To 1.4 meters away from the center of the dial is appropriate, should be fitted sheet tray.
3 , flow = 57 3 / h, should be installed in the stage floor tiles , brick sets 10-20 cm high , allowed the gas meter on the wall.
( B) The minimum spacing of horizontal projection
1 , with a brick chimney 0.3 m
2 , 0.6 m and metal chimneys
3 , with the low-voltage electrical 1.0 m
4 , and the family stove 0.3 m
5 , and 0.7 m cafeteria kitchen
6 , and water heaters 1.5 m
(C ) the quality requirements
To ensure accurate measurement and service life
1, the gas meter installation requirements smooth vertical and horizontal , not tilted , vertical deviation table is not more than 1 cm , the table should be set up support care not to generate additional stress .
2 , the application of the import and export pipeline gas meter pipe or lead pipe , wire port connected to tight, lead pipe bent into a circular shape , the protection of lead caliber, so that does not dent , former table horizontal branch pipe slope risers, after the table level manifold aspect stove .
3 , the low level kitchen table then branch pipe fittings ranging activities in the kitchen board.
4, note the table to prevent loading the wrong direction ; rubber ring may not be distorted, posted flat to put stability and prevent leakage.
5, the flow rate = 57 3 / h of gas meter bypass pipe should be located and installed a bypass valve , about two meters from the ground .
6 , the back and the wall of the gas meter should be kept 10-20 mm distance.
Six Roots flowmeter installation
1 , welding flange connected with the meter should do first welding mold ( flange spool ) , instead of the location and length of flowmeter flange bolt holes . Non- meter line welding, pressure.
2 , meter installation direction : According to the current pipe network conditions , can only be installed vertically must be purged before the first pipe.
3, before or after the meter can be installed at the same pressure level of bellows to eliminate stress . The mounting location must ensure that both sides parallel to the flange plane and on the same axis . When tightening the bolts , the force should be uniform to avoid abnormal meter housing to withstand external stresses .
4 To select a new pipe installation is not allowed to use the old pipe , should pay attention to clean the wall ( between the filter and flow meter )
5 , the horizontal axis position of the meter must be
6 , plate meter housing can be found in the top or the side , never allowed below .
7 , after aeration , notice sent to the meter manufacturers refuel within two weeks .
8, if the meter is installed after the pressure test , air intake filter must be selected in the position before , must not be selected on the meter backward gas pressure test . Must be discharged from the air when the pressure relief vent pipe allowed air intake vent relief from the pressure test .
9 , to open or close the valve must be slow, do not allow a sudden turned on or off .
Regulator, regulator stations
First, the regulator 's classification
A direct -acting : relying only outlet pressure sensitive element ( film ) deformation felt by moving the regulator valve to adjust. The force sensor is the actuator element . So regulating valve moving energy is transferred media.
2 , the indirect -acting : a gas outlet so that the change in pressure of the operating mechanism ( e.g., air command ) operation , power is turned on ( for an external energy source , can be adjusted as a medium) to adjust the valve to move . Indirect force components acting regulator and transmission of sensitive components are separated .
Direct -acting : ( 1 ) LPG Regulator
( 2 ) User regulator
Indirect -acting regulator :
Self- regulator , etc.
Second, the regulator classification
( A ) by the use of the nature of
1 , door station : long pipeline to receive gas through to the gas, which has filtered , regulation, metering devices
2 , district regulator station
3 , a dedicated regulator : gas consumption larger industrial enterprises and large public buildings Users
4, the user surge tank : usually connected with low pressure and medium pressure pipeline network and pipeline network , gas supply residential users
(B ) by adjusting the pressure points
1, high , high-pressure regulator station
2 , high pressure regulator station
3 , high and low pressure regulator station
4 , in the medium-pressure regulator station
5 , low pressure regulator station
(C ) the classification by architectural forms
1 , ground regulator station
2 underground regulator station
3 , box-type regulator station
First, when the LPG valve installation Note:
1 , for longer obsolete or idle valve, disassemble and clean before installation , dust inside the valve port , sand debris also need to rinse .
2, should be installed upright on a horizontal pipe valve vertical and horizontal pipes
3, the valve should be installed on both sides of the control valve , the valve should be enlarged diameter of at least one standard , and install a bypass pipe to prepare for overhaul.
4 , high- pressure relief valve , the pressure gauge should be set low-pressure pipe , in order to adjust the pressure and the change observed in the operation of the valve before and after the valve .
5 , the guide tube should be connected to the pressure of low-pressure pipe , pressure pipe is no guide to set up a safety valve to ensure the reliability and safety relief valve operation.
6 , relief applies only to clean the pipeline liquefied petroleum gas , natural gas , liquid pressure can not act , can not be used pressure liquid containing solid particles .
7 , in the selection , pay attention to the provisions of the pressure relief valve shall not exceed the scope of work in order to ensure reasonable conditions .
8 , the use of low-pressure valves, gate valves should generally meet the inlet and outlet pressure of not more than required 1.5K .
First, the composition of the regulator station
Regulator station is used to stabilize the pipe network pressure regulator and facilities , usually by the regulator , valves , filters, safety devices, consisting of the bypass pipe and measuring instruments , and some have metering equipment.
1 , the valve
2 , the filter
3 , safety devices,
A, safety valve : safety shut-off valve safety relief valves
B, the monitor apparatus : Series
C, shunt regulator device
4 , the bypass tube
5 , measuring instruments
Other facilities : flowmeters, orifice plate and cam device ( outlet pressure , hydraulic conditions )
Silencer to prevent freezing heating device
First, the surge tank installation
When the intermediate pressure gas pipe network directly ( residential and commercial = 0.4mpa, industrial = 0.8mpa) by the user when the rated pressure regulator reduced the required gas appliances working properly , often the user regulator mounted in a metal box calendar hanging on the wall , called the surge tank .
Structure is relatively simple surge tank features a direct -acting regulator, spring-loaded safety relief , and inlet and outlet pressure gauges , valves , filters , pressure sampling port and other accessories all loaded inside a metal box .
Installation
1, the surge tank and the gas pipeline should surge tank inlet and outlet connections purge pipes and strength and tightness test after passing proceed.
2, requires connection flange and gasket with the same gas pipeline .
3, the surge tank is usually hung on the facades of buildings, the installation location is determined in accordance with the design or user consultation .
4 , can be embedded bracket, the bracket bolts can also be fixed to the wall .
5 , the regulator should be firmly installed Euparagonimus box .
6 , surge tank and out of the flange connection with forehead Mu prohibited powerful connections.
7 , the bottom of the surge tank from the ground should be of 1.0-1.2m, when installed on the exterior walls of buildings with gas , surge tank inlet pipe diameter of not more than DN50.
8 , the level of the surge tank to the building door , window or other access to the interior of the net from the slot hole should meet the following requirements :
a, when the regulator inlet pressure = 0.4mpa, not less than 1.5m
b, when the regulator inlet pressure > 0.4mpa time , not less than 3.0m
Regulators shall be installed on the building 's doors and windows below the bottom of the walls and balconies, shall not be installed in the indoor fan inlet wall.
9, the installation of a permanent wall regulator entities walls of their buildings fire resistance rating not less than two .
10 , should have natural ventilation holes on the surge tank .
11 , the surge tank should be positioned so that the surge tank is not a collision , do not affect the visual impact and unpacking operations Mu does not affect traffic , should be able to meet the regulator 's low relief device installation requirements.
( Regulator or regulator station cabinet installation complexity , temporarily in this discussion )
Valve
First, the type of valve
1 , 2 gas cocks , gate 3 , 4 shut-off valves , throttle
5 , 6 ball , butterfly valves 7 , 8 valve , angle valve
9 , valve 10 , check valve 11 , flow valve 12, the safety valve
13 , emergency shut-off valve
Second, pre- installation check
1 , visual inspection
a, the valve should be installed according to the design before the check valve and flange type , size and number of bolts , review product certification and test records.
b, valve components shall not have cracks, holes , trachoma, casting defects such as insufficient sealing surface without any defects, degree of finish and fit to meet the requirements.
c, the valve operating mechanism and turning device to be adjusted as necessary to make the operation flexible , accurate indication .
d, height and tightness pressed into the filler should remain sealed and do not hinder movement of the spindle , and leave some margin.
e, the plug should be positioned mark , and should be fully open to fully closed limit rotation in the 900 range. Core doors at both ends of the transfer class internally threaded cocks its axis should be in the same center line , thread skewed cocks shall not be used .
2, the strength test and tightness test
Gas pipeline valves used should be individually strength and tightness test .
A, strength test : 1.5 times the working pressure . Not less than 5min. Shell filler no leakage is qualified.
B, tightness test : to be nominal , or 1.25 times more than the working pressure .
Passing the test valve shall promptly drained water inside , seal top coat anti-rust oil ( except skim valve required ) , close the valve port closed entrances.
A valve is installed technical requirements
1 , directional
There are signs on the valve body in general , the forward direction of the arrow that gas flow direction . Special attention must not hold against . Because there are a variety of one-way flow of gas valve requirements , such as safety valves, valves , check valves, throttle valves , etc., in order to facilitate the opening and closing valve maintenance, also called the gas from the bottom up through the seat , but the gate when cocks installation , without limiting the flow direction .
2 , the mounting position
Valve should take a long-term operation and maintenance considerations, as easy operation and maintenance , but also pay attention to the aesthetic appearance when assembled .
A, the valve handle can be vertically upward direction , may be inclined to a certain angle or horizontal , but not down to the hand wheel to turn his face to avoid operation ; preferably ground valve handwheel chest , ease of opening and closing ; stem gate valve can not be used underground to prevent the stem from corrosion .
B, the installation location of some valves have special requirements, such as requirements upright valve installed in horizontal pipelines , not tilted , lift check valve required vertical ; swing check valve pin level requirements . In short, to determine the valve according to the principles of its mounted position , otherwise the valve will not work effectively , or even does not work.
3 , cocks installation
Check the specifications, identify damage, remove the cover and threaded excess oil and debris inside the thread , sealing performance test cocks . The gas cock must be taken when installing the appropriate force , according to the size of the cock specifications use different specifications of pipe wrench or spanner to install.
4 , when the threaded valve installation , make sure the thread is intact ; able to do when using a wrench wrench , do not use a pipe wrench to avoid damaging the body appearance.
5 , flanged valves installed, you must ensure that the two flange sections parallel to each other and on the same axis , tighten the bolts should be crossed , the end face of the valve even by force .
6 , the valve flange and threaded connections should be installed in the closed state . When valves and pipe connections butt weld end TIG welding should be adopted to ensure the internal cleaning , welding , valve not closed to prevent thermal deformation .
7 , under normal conditions , the valve is directly connected with the bellows expansion joint , therefore be based on the valve flange and the bellows expansion joint and the size of the gasket , which was cut on both sides of the pipe , leaving the installation location.
8 , when the valve lifting rope tied to the first round or not the stem to prevent damage , should be light hanging, light, non- collision . When placed on the pier , according to the requirements of steady elevation pad , pad level . There must be a strong buttress or bracket will hold the valve , the valve is not allowed under stress floating valve .
Gas Meter
A gas flowmeter Category:
Volume of wet gas flowmeter
Dry film ( slide valve , piston )
Rotor ( Roots table )
Reasoning differential pressure ( plates, nozzles , Venturi )
Velocity ( turbo ) ( flat impeller , spiral impeller )
Vortex style
Second, the use of
1 , the use of film -type pressure is generally not more than 5kpa
Civil, public welfare users <100m3 / h
2 , Roots table
A, the pressure and flow > 100m3 / h
B, high precision, small gap between the rotor and the housing , fewer impurities , to install filtering devices
3 , Wet
A, suitable for low pressure flow rate measurement as a small laboratory
B, can also be used as third-class standard test used to measure gas flow device for household gas meter
4 , differential pressure
A, large flow , gas consumption changed slightly
B, higher cleanliness requirements
C, the temperature required for the metering process , the pressure correction and translation severe
5 , impeller
Used in natural gas
6 , vortex type
Vibratory flowmeter are fluid , it has no moving mechanical parts, large range , measure the volume of traffic when it is almost unaffected by fluid density, pressure, temperature , viscosity and other parameters , faster development.
Third, the film -type gas meter conditions of use
1 , clean coal , gas impurity content is not too high , should follow the " City Gas design specifications " requirement, if the impurity content is too high , it will affect the life and measurement accuracy of gas meters
2 , for low pressure gas pipe -line , apply pressure is generally not more than 5kpa
3, the temperature is generally within the range of claim 0-35 oC, if the temperature is below freezing , freezing the gas in the water condensate , will affect the normal use of the gas meter , when the use of liquefied petroleum gas, a temperature not lower than the dew point temperature.
Fourth, the installation conditions
1, the number of installations
A, each resident piped gas users should set up a separate metering device , just install a gas meter ; civil centralized metering device should be used to display.
B, the public welfare users should at least install a gas meter at each billing unit , such as billing unit is not the same , can be mounted points table
2 , environmental requirements
A, gas meter should be installed in the air temperature is not lower than 0 oC in dry, well ventilated , and easy look-up and maintenance of premises ( film table )
B, prohibited the gas meter installed in bedrooms, bathrooms , steam boiler room, dangerous goods and flammable storage place , and a place similar to the above .
C, Fortune Industrial users of public gas meter should be installed in a separate room.
D, IC card table because there are inheritance circuit board , can not be installed in damp , rain and sun areas.
3, the gas meter itself Conditions
A, factory certification
B, look no obvious damage
C, from the Ministry of factory calibration date more than six months
V. Installation
( A ) mounting height
1 , the flow = 3m3 / h China users
A, high table from the ground = 1.8
B, median tables 1.4-1.7 m from the ground
C, low table is 0.1 meters from the ground
Residents user traffic school table table should be appropriate. When multi-table hanging on the same wall , spacing between tables should be large
0.15 m , should generally be left in front of the table space is not less than 1 m .
2, the flow 3-5 m 3 / h film sheet can be installed on the ground type , can be mounted on a wall. To 1.4 meters away from the center of the dial is appropriate, should be fitted sheet tray.
3 , flow = 57 3 / h, should be installed in the stage floor tiles , brick sets 10-20 cm high , allowed the gas meter on the wall.
( B) The minimum spacing of horizontal projection
1 , with a brick chimney 0.3 m
2 , 0.6 m and metal chimneys
3 , with the low-voltage electrical 1.0 m
4 , and the family stove 0.3 m
5 , and 0.7 m cafeteria kitchen
6 , and water heaters 1.5 m
(C ) the quality requirements
To ensure accurate measurement and service life
1, the gas meter installation requirements smooth vertical and horizontal , not tilted , vertical deviation table is not more than 1 cm , the table should be set up support care not to generate additional stress .
2 , the application of the import and export pipeline gas meter pipe or lead pipe , wire port connected to tight, lead pipe bent into a circular shape , the protection of lead caliber, so that does not dent , former table horizontal branch pipe slope risers, after the table level manifold aspect stove .
3 , the low level kitchen table then branch pipe fittings ranging activities in the kitchen board.
4, note the table to prevent loading the wrong direction ; rubber ring may not be distorted, posted flat to put stability and prevent leakage.
5, the flow rate = 57 3 / h of gas meter bypass pipe should be located and installed a bypass valve , about two meters from the ground .
6 , the back and the wall of the gas meter should be kept 10-20 mm distance.
Six Roots flowmeter installation
1 , welding flange connected with the meter should do first welding mold ( flange spool ) , instead of the location and length of flowmeter flange bolt holes . Non- meter line welding, pressure.
2 , meter installation direction : According to the current pipe network conditions , can only be installed vertically must be purged before the first pipe.
3, before or after the meter can be installed at the same pressure level of bellows to eliminate stress . The mounting location must ensure that both sides parallel to the flange plane and on the same axis . When tightening the bolts , the force should be uniform to avoid abnormal meter housing to withstand external stresses .
4 To select a new pipe installation is not allowed to use the old pipe , should pay attention to clean the wall ( between the filter and flow meter )
5 , the horizontal axis position of the meter must be
6 , plate meter housing can be found in the top or the side , never allowed below .
7 , after aeration , notice sent to the meter manufacturers refuel within two weeks .
8, if the meter is installed after the pressure test , air intake filter must be selected in the position before , must not be selected on the meter backward gas pressure test . Must be discharged from the air when the pressure relief vent pipe allowed air intake vent relief from the pressure test .
9 , to open or close the valve must be slow, do not allow a sudden turned on or off .
Regulator, regulator stations
First, the regulator 's classification
A direct -acting : relying only outlet pressure sensitive element ( film ) deformation felt by moving the regulator valve to adjust. The force sensor is the actuator element . So regulating valve moving energy is transferred media.
2 , the indirect -acting : a gas outlet so that the change in pressure of the operating mechanism ( e.g., air command ) operation , power is turned on ( for an external energy source , can be adjusted as a medium) to adjust the valve to move . Indirect force components acting regulator and transmission of sensitive components are separated .
Direct -acting : ( 1 ) LPG Regulator
( 2 ) User regulator
Indirect -acting regulator :
Self- regulator , etc.
Second, the regulator classification
( A ) by the use of the nature of
1 , door station : long pipeline to receive gas through to the gas, which has filtered , regulation, metering devices
2 , district regulator station
3 , a dedicated regulator : gas consumption larger industrial enterprises and large public buildings Users
4, the user surge tank : usually connected with low pressure and medium pressure pipeline network and pipeline network , gas supply residential users
(B ) by adjusting the pressure points
1, high , high-pressure regulator station
2 , high pressure regulator station
3 , high and low pressure regulator station
4 , in the medium-pressure regulator station
5 , low pressure regulator station
(C ) the classification by architectural forms
1 , ground regulator station
2 underground regulator station
3 , box-type regulator station
First, when the LPG valve installation Note:
1 , for longer obsolete or idle valve, disassemble and clean before installation , dust inside the valve port , sand debris also need to rinse .
2, should be installed upright on a horizontal pipe valve vertical and horizontal pipes
3, the valve should be installed on both sides of the control valve , the valve should be enlarged diameter of at least one standard , and install a bypass pipe to prepare for overhaul.
4 , high- pressure relief valve , the pressure gauge should be set low-pressure pipe , in order to adjust the pressure and the change observed in the operation of the valve before and after the valve .
5 , the guide tube should be connected to the pressure of low-pressure pipe , pressure pipe is no guide to set up a safety valve to ensure the reliability and safety relief valve operation.
6 , relief applies only to clean the pipeline liquefied petroleum gas , natural gas , liquid pressure can not act , can not be used pressure liquid containing solid particles .
7 , in the selection , pay attention to the provisions of the pressure relief valve shall not exceed the scope of work in order to ensure reasonable conditions .
8 , the use of low-pressure valves, gate valves should generally meet the inlet and outlet pressure of not more than required 1.5K .
First, the composition of the regulator station
Regulator station is used to stabilize the pipe network pressure regulator and facilities , usually by the regulator , valves , filters, safety devices, consisting of the bypass pipe and measuring instruments , and some have metering equipment.
1 , the valve
2 , the filter
3 , safety devices,
A, safety valve : safety shut-off valve safety relief valves
B, the monitor apparatus : Series
C, shunt regulator device
4 , the bypass tube
5 , measuring instruments
Other facilities : flowmeters, orifice plate and cam device ( outlet pressure , hydraulic conditions )
Silencer to prevent freezing heating device
First, the surge tank installation
When the intermediate pressure gas pipe network directly ( residential and commercial = 0.4mpa, industrial = 0.8mpa) by the user when the rated pressure regulator reduced the required gas appliances working properly , often the user regulator mounted in a metal box calendar hanging on the wall , called the surge tank .
Structure is relatively simple surge tank features a direct -acting regulator, spring-loaded safety relief , and inlet and outlet pressure gauges , valves , filters , pressure sampling port and other accessories all loaded inside a metal box .
Installation
1, the surge tank and the gas pipeline should surge tank inlet and outlet connections purge pipes and strength and tightness test after passing proceed.
2, requires connection flange and gasket with the same gas pipeline .
3, the surge tank is usually hung on the facades of buildings, the installation location is determined in accordance with the design or user consultation .
4 , can be embedded bracket, the bracket bolts can also be fixed to the wall .
5 , the regulator should be firmly installed Euparagonimus box .
6 , surge tank and out of the flange connection with forehead Mu prohibited powerful connections.
7 , the bottom of the surge tank from the ground should be of 1.0-1.2m, when installed on the exterior walls of buildings with gas , surge tank inlet pipe diameter of not more than DN50.
8 , the level of the surge tank to the building door , window or other access to the interior of the net from the slot hole should meet the following requirements :
a, when the regulator inlet pressure = 0.4mpa, not less than 1.5m
b, when the regulator inlet pressure > 0.4mpa time , not less than 3.0m
Regulators shall be installed on the building 's doors and windows below the bottom of the walls and balconies, shall not be installed in the indoor fan inlet wall.
9, the installation of a permanent wall regulator entities walls of their buildings fire resistance rating not less than two .
10 , should have natural ventilation holes on the surge tank .
11 , the surge tank should be positioned so that the surge tank is not a collision , do not affect the visual impact and unpacking operations Mu does not affect traffic , should be able to meet the regulator 's low relief device installation requirements.
( Regulator or regulator station cabinet installation complexity , temporarily in this discussion )
Valve
First, the type of valve
1 , 2 gas cocks , gate 3 , 4 shut-off valves , throttle
5 , 6 ball , butterfly valves 7 , 8 valve , angle valve
9 , valve 10 , check valve 11 , flow valve 12, the safety valve
13 , emergency shut-off valve
Second, pre- installation check
1 , visual inspection
a, the valve should be installed according to the design before the check valve and flange type , size and number of bolts , review product certification and test records.
b, valve components shall not have cracks, holes , trachoma, casting defects such as insufficient sealing surface without any defects, degree of finish and fit to meet the requirements.
c, the valve operating mechanism and turning device to be adjusted as necessary to make the operation flexible , accurate indication .
d, height and tightness pressed into the filler should remain sealed and do not hinder movement of the spindle , and leave some margin.
e, the plug should be positioned mark , and should be fully open to fully closed limit rotation in the 900 range. Core doors at both ends of the transfer class internally threaded cocks its axis should be in the same center line , thread skewed cocks shall not be used .
2, the strength test and tightness test
Gas pipeline valves used should be individually strength and tightness test .
A, strength test : 1.5 times the working pressure . Not less than 5min. Shell filler no leakage is qualified.
B, tightness test : to be nominal , or 1.25 times more than the working pressure .
Passing the test valve shall promptly drained water inside , seal top coat anti-rust oil ( except skim valve required ) , close the valve port closed entrances.
A valve is installed technical requirements
1 , directional
There are signs on the valve body in general , the forward direction of the arrow that gas flow direction . Special attention must not hold against . Because there are a variety of one-way flow of gas valve requirements , such as safety valves, valves , check valves, throttle valves , etc., in order to facilitate the opening and closing valve maintenance, also called the gas from the bottom up through the seat , but the gate when cocks installation , without limiting the flow direction .
2 , the mounting position
Valve should take a long-term operation and maintenance considerations, as easy operation and maintenance , but also pay attention to the aesthetic appearance when assembled .
A, the valve handle can be vertically upward direction , may be inclined to a certain angle or horizontal , but not down to the hand wheel to turn his face to avoid operation ; preferably ground valve handwheel chest , ease of opening and closing ; stem gate valve can not be used underground to prevent the stem from corrosion .
B, the installation location of some valves have special requirements, such as requirements upright valve installed in horizontal pipelines , not tilted , lift check valve required vertical ; swing check valve pin level requirements . In short, to determine the valve according to the principles of its mounted position , otherwise the valve will not work effectively , or even does not work.
3 , cocks installation
Check the specifications, identify damage, remove the cover and threaded excess oil and debris inside the thread , sealing performance test cocks . The gas cock must be taken when installing the appropriate force , according to the size of the cock specifications use different specifications of pipe wrench or spanner to install.
4 , when the threaded valve installation , make sure the thread is intact ; able to do when using a wrench wrench , do not use a pipe wrench to avoid damaging the body appearance.
5 , flanged valves installed, you must ensure that the two flange sections parallel to each other and on the same axis , tighten the bolts should be crossed , the end face of the valve even by force .
6 , the valve flange and threaded connections should be installed in the closed state . When valves and pipe connections butt weld end TIG welding should be adopted to ensure the internal cleaning , welding , valve not closed to prevent thermal deformation .
7 , under normal conditions , the valve is directly connected with the bellows expansion joint , therefore be based on the valve flange and the bellows expansion joint and the size of the gasket , which was cut on both sides of the pipe , leaving the installation location.
8 , when the valve lifting rope tied to the first round or not the stem to prevent damage , should be light hanging, light, non- collision . When placed on the pier , according to the requirements of steady elevation pad , pad level . There must be a strong buttress or bracket will hold the valve , the valve is not allowed under stress floating valve .
