Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB 27790-2011 City gas pressure regulators. In addition to editorial changes, the following main technical changes have been made with respect to GB 27790-2011:
——The scope is modified (see clause 1; clause 1 of Edition 2011);
——Some terms and definitions are modified or added (see clause 3; clause 3 of Edition 2011);
——The classification and model designation are modified (see clause 4; clause 4 of Edition 2011);
——The structure and material are modified (see clause 5; clause 5 of Edition 2011);
——The special requirements for meter pressure regulator are added (see 5.2.3 and 6.13);
——The technical requirements for nondestructive testing of steel pressure-bearing parts are added (see 5.3.2.5);
——The technical requirements for fail state, integrated shut-off device, integrated monitor and integrated release device are added (see 6.9, 6.10, 6.11 and 6.12);
——The requirements for gas strength test are added (see 7.3.1);
——The methods for gas resistance test of diaphragm and low-temperature resistance test of diaphragm are modified (see 7.4.2 and 7.4.3; 7.4.2 and 7.4.3 of Edition 2011);
——The requirement that no intermediate static characteristic test be conducted when the applicable range of inlet pressure and outlet pressure of pressure regulator is too narrow is added (see 7.6.1.1);
——The inspection method for failure state is added (see 7.10);
——The test method for integrated shut-off device is added (see 7.11);
——The test method for integrated monitor is added (see 7.12);
——The test method for integrated release device is added (see 7.13);
——The test methods for torsion resistance and bending resistance of meter pressure regulator are added (see 7.14);
——the inspection rules are modified (see clause 8; clause 8 of Edition 2011);
——The marking and label of pressure regulator are modified (see 9.1; 9.1 of Edition 2011);
——The operating instructions of pressure regulator are modified and the requirements for providing noise and corresponding operating conditions are added (see 9.2; 9.2 of Edition 2011);
——The physical and mechanical properties of rubber materials as well as gas resistance are modified (see Annex A; Annex A of Edition 2011).
This standard was proposed by and is under the jurisdiction of the Ministry of Housing and Urban-Rural Development of the People's Republic of China.
The previous edition of this standard is as follows:
——GB 27790-2011.
City gas pressure regulator
1 Scope
This standard specifies terms, definitions and symbols, classification and labelling, structure and materials, requirements, test methods, inspection rules, marking, label and operating instructions as well as packaging, transport and storage of city gas pressure regulator (hereinafter referred to as pressure regulator).
This standard is applicable to the pressure regulators with a nominal diameter up to 400mm, an operating temperature range not exceeding -20℃~60℃ with the lower limit not less than the dew point temperature of the gas, and an inlet pressure up to 10.0MPa.
This standard is not applicable to the pressure regulators for liquefied petroleum gas in cylinders and those for dimethyl ether.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 150 (all parts) Pressure vessel
GB/T 191 Packaging - Pictorial marking for handling of goods
GB/T 229 Metallic materials - Charpy pendulum impact test method
GB/T 528 Rubber, vulcanized or thermoplastic - Determination of tensile stress-strain properties
GB/T 531.1 Rubber vulcanized or thermoplastic - Determination of indentation hardness - Part 1: Durometer method (Shore hardness)
GB/T 699 Quality carbon structure steels
GB/T 1047 Pipework components - Definition and selection of nominal size
GB/T 1173 Casting aluminium alloy
GB/T 1220 Stainless steel bars
GB/T 1239.2 Cold coiled helical springs technical specifications - Part 2: Compressions spring
GB/T 1348 Spheroidal graphite iron castings
GB/T 1591 High strength low alloy structural steels
GB/T 1681 Rubber - Determination of rebound resilience of vulcanizates
GB/T 1682 Rubber, vulcanized - Determination of low-temperature brittleness - Single test piece method
GB/T 1690 Rubber, vulcanized or thermoplastic - Determination of the effect of liquids
GB/T 3077 Alloy structure steels
GB/T 3191 Aluminium and aluminium alloys extruded bars, rods
GB/T 3280 Cold rolled stainless steel plate, sheet and strip
GB/T 3452.1 Fluid power systems - O-rings - Part 1: Inside diameters, cross-sections, tolerances and size identification code
GB/T 3452.2 Fluid power systems - O-rings - Part 2: Quality acceptance criteria
GB/T 3512 Rubber, vulcanized or thermoplastic - Accelerated ageing and heat resistance tests - Air-oven method
GB/T 4423 Copper and copper-alloy cold-drawn rod and bar
GB/T 6388 Transport package shipping mark
GB/T 7233.1 Steel castings - Ultrasonic examination - Part 1: Steel castings for general purposes
GB/T 7306.1 Pipe threads with 55 degree thread angle where pressure-tight joints are made on the threads - Part 1: Parallel internal and taper external threads
GB/T 7306.2 Pipe threads with 55 degree thread angle where pressure-tight joints are made on the threads - Part 2: Taper internal and external threads
GB/T 7759 (all parts) Rubber, vulcanized or thermoplastic - Determination of compression set
GB/T 7762 Rubber, vulcanized or thermoplastic - Resistance to ozone cracking - Static strain test
GB/T 9124.1 Steel pipe flanges - Part 1: PN designated
GB/T 9124.2 Steel pipe flanges - Part 2: Class designated
GB/T 9440 Malleable iron castings
GB/T 9443 Steel and iron castings - Liquid penetrant inspection
GB/T 9444 Steel and iron castings - Magnetic particle inspection
GB/T 9969 General principles for preparation of instructions for use of industrial products
GB/T 12224 General requirements for industrial steel valves
GB/T 12227 General purpose industrial valve - Specification of spheroidal graphite iron castings
GB/T 12228 General purpose industrial valves - Specification of carbon steel forgings
GB/T 12229 General purpose industrial valves - Specification of carbon steel castings
GB/T 12716 Pipe threads with the thread angle of 60 degrees where pressure-tight joints are made on threads
GB/T 13306 Plates
GB/T 13384 General specifications for packing of mechanical and electrical product
GB/T 13934 Rubber, vulcanized or thermoplastic - Determination of flex cracking and crack growth (De Mattia)
GB/T 15115 Die casting aluminium alloys
GB/T 17213.15 Industrial-process control valves - Part 8-3: Noise considerations - Control valve aerodynamic noise prediction method
GB/T 20801.5 Pressure piping code - Industrial piping - Part 5: Inspection and testing
GB/T 23934 Hot formed helical compression springs - Technical Requirement
GB/T 32249 Aluminum and aluminum-alloy die forgings, hand forgings and rolled ring forgings - General specification
GB/T 38343 Technical specification for flange joints installation
GB 50058 Code for design of electrical installations in explosive atmospheres
CJ/T 180-2014 Manually operated gas valves for gas installations of buildings
CJ/T 335-2010 Slam-shut valves and relief valves for city gas
HG/T 20592 Steel pipe flanges (PN designated)
HG/T 20615 Steel pipe flanges (Class designated)
JB/T 6440 Methods of radiographic examination for steel castings valves
JB/T 7248 Technical specification for low temperature service steel casting for valves
JB/T 7927 Valve cast steel visual quality requirements
JB/T 7944 Coiled helical springs - Sampling inspection
NB/T 47008 Carbon steel and alloy steel forgings for pressure equipment
NB/T 47009 Alloy steel forgings for low temperature pressure equipment
NB/T 47010 Stainless and heat-resisting steel forgings for pressure equipment
NB/T 47013 (all parts) Nondestructive testing of pressure equipments
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this standard, the following terms and definitions apply.
3.1.1
gas pressure regulator
equipment whose function is to automatically regulate the gas outlet pressure to maintain it within certain pressure range
3.1.2
series of pressure regulator
generic term for pressure regulators with the same design concept, similar structure but different nominal diameter
3.1.3
direct acting pressure regulator
pressure regulators which have a direct control by virtue of the outlet pressure variation over the actuator which drives the control members to move
Note: See Figure 1 for an example of the action principle of the direct acting pressure regulator.
Key:
1——setting element;
2——actuator;
3——diaphragm;
4——sensing line;
5——valve seats;
6——seat ring;
7——regulator body;
8——control member;
9——casing of actuator;
10——breather/exhaust line;
11——metallic partition;
1＋3——controller;
Figure 1 Example of direct acting pressure regulator
3.1.4
indirect acting pressure regulator
pressure regulators which control by virtue of the outlet pressure variation over the actuator which drives the control members to move after the amplification of the pilot
Note: See Figure 2 for an example of the indirect acting pressure regulator.
Key:
1——pilot;
2——process line;
3——actuator;
4——sensing line;
5——motorization chamber;
6——valve seats;
7——seat ring;
8——regulator body;
9——control member;
10——metallic partition;
11——casing of actuator;
Figure 2 Example of indirect acting pressure regulator
3.1.5
meter pressure regulator
pressure regulator installed in front of the user's gas meter, with a nominal diameter not greater than DN25 and a maximum inlet pressure not greater than 0.2 MPa
3.1.6
integrated monitor
pressure regulating unit connected in series with the working pressure regulator, which starts to operate when the outlet pressure of the pressure regulator exceeds the set range of the working pressure regulator to maintain the outlet pressure of the pressure regulator within the allowable range
3.1.7
nominal diameter of pressure regulator
nominal diameter of pressure regulator inlet, indicating pressure regulator dimensions.
3.1.8
nominal pressure
numerical marking code concerned to pressure, rounded to an integral
Note: In this standard, it is used to express the nominal pressure at inlet and outlet flange of the pressure regulators.
3.1.9
design pressure
pressure value which is used to determine strength of the casing or other parts at appropriate design temperature
3.1.10
inlet pressure range
pressure range within which the given accuracy class at pressure regulator inlet is guaranteed
Note: The same pressure regulator may have different inlet pressure ranges.
3.1.11
maximum inlet pressure
maximum inlet pressure value permissible within inlet pressure range
3.1.12
minimum inlet pressure
minimum inlet pressure value permissible within inlet pressure range
3.1.13
outlet pressure range
pressure range within which the given accuracy class at pressure regulator outlet is guaranteed
Note: The same pressure regulator may have different outlet pressure ranges, and the pressure regulator may obtain the required outlet pressure range by replacing certain parts.
3.1.14
maximum outlet pressure
maximum outlet pressure value permissible within outlet pressure range
3.1.15
minimum outlet pressure
minimum outlet pressure value permissible within outlet pressure range
3.1.16
reference conditions
gas state where the temperature is 15℃ and absolute pressure is 101.325 kPa
3.1.17
volumetric flow rate
gas volume in reference conditions which flows through the pressure regulator in unit time
Note: The unit is m3/h.
3.1.18
flow coefficient
air flow passed when the absolute pressure is opened fully at the critical condition where the inlet absolute pressure is 0.243kPa and the temperature is 15℃
Note: The unit is m3/h.
3.1.19
performance
expressing the outlet pressure as a function of the inlet pressure and volumetric flow rate
3.1.20
performance curve
graphic representation of the outlet pressure as a function of the volumetric flow rate by changing volumetric flow rate (from increase to decrease) in case of constant inlet pressure and adjustment condition
Note: This standard adopts the performance curve when the inlet temperature is 15℃.
3.1.21
family of performance curves
set of performance curves obtained at different inlet pressures in the same adjustment condition
3.1.22
set point
nominal outlet pressure of a family of performance curves of the pressure regulator
Note: The set point may be equal to the rated outlet pressure.
3.1.23
hysteresis band
difference between two outlet pressure values corresponding to the same volumetric flow rate when the volumetric flow rate increases and decreases on one performance curve
3.1.24
motorization pressure
gas pressure within high pressure chamber of pressure regulator actuator
3.1.25
stable conditions
conditions where the outlet pressure are gradually changing to a stable value after interference generation
3.1.26
accuracy
percentage of average value of the absolute values of maximum positive deviation and maximum negative deviation between actual outlet pressure and set point within operating range on the same family of performance curves to the set point
3.1.27
accuracy class
maximum permissible value of accuracy multiplied by 100
3.1.28
lock-up pressure
outlet pressure at zero volumetric flow rate on performance curve when the control member of pressure regulator is at a lock-up position
Note: The time from the volumetric flow rate at lock-up point to the zero volumetric flow rate shall be greater than the response time for locking up the pressure regulator.
3.1.29
lock-up pressure class
maximum permissible value of ratio of difference between actual lock-up pressure and set point to set point multiplied by 100
3.1.30
maximum accuracy flow rate
minimum one among the maximum flow rates capable of guaranteeing the given accuracy class for inlet pressure range under specified set point
3.1.31
minimum accuracy flow rate
maximum one among the minimum flow rate or the minimum flow rate in quiescent operation capable of guaranteeing the given accuracy class for inlet pressure range under specified set point
3.1.32
lock-up pressure zone
zone between zero flow rate and minimum flow rate on each corresponding performance curve of inlet pressure and set point (see Zone 1 in Figure 3)
Key:
p2——outlet pressure;
p1——inlet pressure;
AC——accuracy class;
SG——lock-up pressure class;
Q——volumetric flow rate;
Qmax,p1——maximum flow rate under p1;
p2s——set point;
Qmin,p1——minimum flow rate under p1;
1——lock-up pressure zone SZ.
Figure 3 Lock-up pressure zone (stable condition)
3.1.33
class of lock-up pressure zone
maximum permissible value of ratio of minimum flow rate to maximum flow rate multiplied by 100
3.1.34
class of lock-up pressure zone of family of performance curves
maximum permissible value of ratio of minimum accuracy flow rate to maximum accuracy flow rate on the family of performance curves multiplied by 100
3.1.35
operating temperature range
temperature range of medium and body in which the pressure regulator components and additional devices are capable of operating normally
3.1.36
control member
movable element installed in the flow passage of the pressure regulator, which is used for controlling the opening degree of the flow passage of the pressure regulator
3.1.37
fail close pressure regulator
pressure regulator that automatically closes or tends to close when the main diaphragm fails or the power system that moves the control member fails
3.1.38
fail open pressure regulator
pressure regulator that automatically opens or tends to open when the main diaphragm fails or the power system that moves the control member fails
3.1.39
integrated release device
self-actuated release unit installed on the pressure regulator body and, when the control pressure reaches the release pressure set value, releasing gas to the atmosphere with limited flow rate
3.1.40
integrated shut-off device
self-actuated shut-off device installed on the pressure regulator body
Note: It is characterized in that when the pressure regulator works normally, the integrated shut-off device is on, when the pressure at the outlet of the pressure regulator reaches the set value of shut-off pressure, the gas passage is automatically cut off by virtue of the gas pressure at the outlet of the pressure regulator, and the actuator is reset manually after troubleshooting the gas system.
3.2 Symbols
For the purposes of this standard, the symbols listed in Table 1 apply.
Table 1 Symbols and explanations
S.N. Symbol Unit Explanation
1 A % Accuracy
2 Amin % Elongation
3 AC — Accuracy class
4 AQ — Shut-off pressure accuracy class
5 Cg — Flow coefficient
6 Cgi — Flow coefficient under test conditions
7 Cgx — Flow coefficient of pressure regulator under partial opening
8 DN — Letter symbol before nominal diameter identification
9 d — Relative density of test medium
10 K1j — Shape coefficient under test conditions
11 K1 — Shape coefficient
12 m — Number of test conditions under subcritical flow condition in the flow coefficient Cg test
13 n — Number of test conditions under critical flow condition in the flow coefficient Cg test
14 p MPa Design pressure
15 p1 MPa Inlet pressure
16 p1av MPa Medium value between maximum inlet pressure and minimum inlet pressure
17 p1t Pa Pressure of test medium in the pressure-bearing chamber at the first measurement
18 p1max MPa Maximum inlet pressure
19 p1min MPa Minimum inlet pressure
20 p2 MPa Outlet pressure
21 p2c MPa Initial outlet pressure
22 p2t Pa Pressure of test medium in the pressure-bearing chamber at the second measurement
23 p2int MPa Initial outlet pressure between p2min and p2max
24 p2max MPa Maximum outlet pressure within outlet pressure range
25 p2min MPa Minimum outlet pressure within outlet pressure range
26 p2s MPa Set point
27 pa MPa或Pa Atmospheric pressure
28 pb MPa Lock-up pressure
29 pb1 MPa Pressure obtained by carrying out thermometric correction for lock-up pressure measured at the first time in the lock-up pressure test
30 pb2 MPa Pressure obtained by carrying out thermometric correction for lock-up pressure measured at the second time in the lock-up pressure test
31 pn Pa Reference pressure
32 pta MPa Actual value of shut-off pressure
33 pts MPa Set value of shut-off pressure
34
MPa Lock-up pressure measured at the second time in the lock-up pressure test
35 pmax MPa Maximum design pressure
36 Q m3/h Volumetric flow rate
37 Qi m3/h Calculated leakage of a pressure-bearing chamber
38 Qm m3/h Volumetric flow rate measured when pressure regulator inlet temperature is t1
39 Qmax m3/h Maximum flow rate
40 Qmax, p1min m3/h Maximum flow rate when inlet pressure is p1min
41 Qmax, p1 m3/h Maximum flow rate at a certain inlet pressure
42 Qmin m3/h Minimum flow rate
43 Qmin, p1 m3/h Minimum flow rate at a certain inlet pressure
44 Qmin, p1av m3/h Minimum flow rate when inlet pressure is p1av
45 Qmin, p1min m3/h Minimum flow rate at minimum inlet pressure
46 Qmin, p1max m3/h Minimum flow rate at maximum inlet pressure
47 QL m3/h Maximum test volumetric flow rate of a characteristic line
48 QR m3/h Maximum flow rate provided by test bench
49 SG — Lock-up pressure class
50 SZ — Class of lock-up pressure zone
51 SZp2 — Class of lock-up pressure zone of family of performance curves
52 t h Pressure-holding time
53 t1 ℃ Test medium temperature in front of pressure regulator
54 t1t ℃ Temperature of test medium within pressure-bearing chamber during the measurement for the first time
55 t2t ℃ Temperature of test medium within pressure-bearing chamber during the measurement for the second time
56 tb1 ℃ Pressure regulator outlet temperature measured for the first time in the lock-up pressure test
57 tb2 ℃ Pressure regulator outlet temperature measured for the second time in the lock-up pressure test
58 V m3 Volume of pressure-bearing chamber
59 △＋ MPa Positive deviation between actual value and set point of outlet pressure
60 △－ MPa Negative deviation between actual value and set point of outlet pressure
61 △p MPa Minimum differential pressure at inlet and outlet at which the accuracy class may be guaranteed by the pressure regulator
62 △t h Interval between two measurements
63 △ph Pa Hysteresis band
64 △pt Pa Corrected pressure drop
65 △pmax MPa Maximum differential pressure borne by diaphragm
66 δ5 % Elongation of steels
67 δp1 MPa Inlet pressure range
68 δp2 MPa Outlet pressure range
4 Classification and model
4.1 Classification
The classification of pressure regulators shall meet the requirements of Table 2.
Table 2 Classification of pressure regulators
S.N. Classification method Category
1 Working principle Action mode Direct acting, and indirect acting
Failure state Fail-open, and fail-close
2 Connection type Flange, and thread
3 Maximum inlet pressure/MPa 0.01, 0.2, 0.4, 0.8, 1.6, 2.0, 2.5, 4.0, 6.3 and 10.0
4.2 Model
4.2.1 Model preparation
Product model preparation shall meet the following requirements:
a) The model preparation of pressure regulators shall be in the following format:
b) The working principle code of pressure regulators shall meet the requirements of Table 3;
Table 3 Operating principle codes of pressure regulator
Operating principle code Operating principle
Action mode Failure state
Direct acting Indirect acting Fail open Fail close
Z1 √ - √ -
Z2 √ - - √
J1 - √ √ -
J2 - √ - √
ZB √ - √ -
Notes:
1. "√" indicates that it is applicable; "-" indicates that it is not applicable.
2 ZB represents the meter pressure regulator.
c) The nominal diameter of pressure regulator refers to the nominal diameter of inlet connection;
d) The maximum inlet pressure, p1max, is divided into 9 grades, i.e., 0.01MPa, 0.2MPa, 0.4MPa, 0.8MPa, 1.6MPa, 2.5MPa, 4.0MPa, 6.3MPa and 10.0MPa, with the pressure value in MPa marked.
e) As for the connection type, L is for threaded connection, and the code is omitted in case of flanged connection;
f) Custom numbers, including manufacturer-defined numbers, such as series of pressure regulator.
4.2.2 Example
Examples for the models of pressure regulators are as follows:
a) RTJ1-150/0.4-A, indicating a fail open indirect acting pressure regulator which has a nominal diameter of DN150, a maximum inlet pressure of 0.4 MPa and a custom number of A, and is subjected to flange connection;
b) RTZB-15/0.01 L, indicating a meter pressure regulator which has a nominal diameter of DN15 and a maximum inlet pressure of 0.01MPa and is subjected to threaded connection.
5 Structure and material
5.1 General requirements
5.1.1 Design pressure
5.1.1.1 Metallic pressure-bearing parts
The design pressure of metallic pressure-bearing parts (include metallic parts bearing pressure at normal operation or metallic parts bearing pressure after diaphragm and differential pressure seal fails) shall meet the following requirements:
a) When the metallic pressure-bearing parts are subjected to inlet pressure p1, their design pressure shall not be less than the maximum inlet pressure and shall not be less than 0.4 MPa;
b) When metallic pressure-bearing parts are protected by safety protection devices, and the pressure to which they are subjected after the diaphragm or differential pressure seal fails is less than the inlet pressure and greater than or equal to normal operating pressure, the design pressure of the metallic pressure-bearing parts shall not be less than 1.1 times the pressure borne by them after the failure of diaphragm or differential pressure seal, or the design pressure specified in Item a) may be adopted;
c) For pressure-bearing parts which are subjected to a pressure less than the normal operating pressure after the failure of diaphragm or differential pressure seal, the design pressure shall not be less than 1.1 times the maximum normal operating pressure, or the design pressure specified in Item a) may be adopted;
5.1.1.2 Metallic partition
The design pressure of metallic partition shall not be less than 1.1 times the difference between maximum pressure at high-pressure side and minimum pressure at low-pressure side, however the design pressure of metallic partition in the valve shall meet the requirements of 5.1.1.1a).
5.1.1.3 Diaphragm
The design pressure of diaphragm shall meet the following requirements:
a) When the maximum differential pressure, △pmax, borne by the diaphragm is less than 0.015 MPa, the design pressure of the diaphragm shall not be less than 0.02 MPa;
b) When 0.015 MPa≤△pmax<0.5 MPa, the design pressure of the diaphragm shall not be less than 1.33△pmax;
c) When △pmax≥0.5 MPa, the design pressure of the diaphragm shall not be less than 1.1△pmax and it shall not be less than 0.665 MPa.
5.1.2 Operating temperature range
The operating temperature ranges of the pressure regulators shall be -10℃~60℃ or -20℃~60℃.
5.2 Structure
5.2.1 Connection type at inlet and outlet
5.2.1.1 The connection between the pressure regulator and the upstream and downstream pipelines shall meet the following requirements:
a) The connection dimension and sealing surface type of the flange shall meet the requirements of GB/T 9124.1, GB/T 9124.2, HG/T 20592 or HG/T 20615.
b) Pipe threads shall only be used for pressure regulators with a nominal diameter not greater than DN50, and shall meet the requirements of GB/T 7306.1, GB/T 7306.2 or GB/T 12716.
5.2.1.2 The nominal pressure of the flange shall not be less than the design pressure of the pressure regulator body, and shall be selected from the following series of values: 0.6 MPa, 1.0 MPa, 1.6 MPa, 2.0 MPa, 2.5 MPa, 4.0 MPa, 5.0 MPa, 6.3 MPa, 10.0 MPa and 11.0 MPa.
5.2.1.3 The nominal pressure of the inlet and outlet flanges of the pressure regulator shall be the same.
Foreword i
1 Scope
2 Normative references
3 Terms, definitions and symbols
3.1 Terms and definitions
3.2 Symbols
4 Classification and model
4.1 Classification
4.2 Model
5 Structure and material
5.1 General requirements
5.2 Structure
5.3 Materials
6 Requirements
6.1 Appearance
6.2 Strength of pressure containing part
6.3 Inspection for finished product of diaphragm
6.4 External seal
6.5 Performance
6.6 Flow coefficient, Cg
6.7 Adaptability at limit temperature
6.8 Durability
6.9 Failure state
6.10 Performance of integrated shut-off device
6.11 Performance of integrated monitor
6.12 Performance of integrated release device
6.13 Torsion resistance and bending resistance of meter pressure regulator
7 Test methods
7.1 General requirements
7.2 Appearance
7.3 Strength of pressure-bearing parts
7.4 Inspection of finished diaphragm
7.5 External seal
7.6 Performance
7.7 Flow coefficient Cg
7.8 Adaptability at limit temperature
7.9 Durability
7.10 Failure state
7.11 Integrated shut-off device
7.12 Integrated monitor
7.13 Integrated release device
7.14 Torsion resistance and bending resistance of meter pressure regulator
8 Inspection rules
8.1 Inspection classification
8.2 Inspection items
8.3 End-of-manufacturing inspection
8.4 Type inspection
8.5 Judging rules
9 Marking, label and operating instructions
9.1 Marking and label
9.2 Operating instructions
10 Packaging, transport and storage
10.1 Packaging
10.2 Transport
10.3 Storage
Annex A (Normative) Physical and mechanical properties of rubber materials and gas resistance
Annex B (Informative) Storage of rubber parts of pressure regulators
Annex C (Normative) Alternative method for determining flow coefficient of mass flow regulators
Annex D (Informative) Flow characteristic
Annex E (Informative) Noise
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB 27790-2011 City gas pressure regulators. In addition to editorial changes, the following main technical changes have been made with respect to GB 27790-2011:
——The scope is modified (see clause 1; clause 1 of Edition 2011);
——Some terms and definitions are modified or added (see clause 3; clause 3 of Edition 2011);
——The classification and model designation are modified (see clause 4; clause 4 of Edition 2011);
——The structure and material are modified (see clause 5; clause 5 of Edition 2011);
——The special requirements for meter pressure regulator are added (see 5.2.3 and 6.13);
——The technical requirements for nondestructive testing of steel pressure-bearing parts are added (see 5.3.2.5);
——The technical requirements for fail state, integrated shut-off device, integrated monitor and integrated release device are added (see 6.9, 6.10, 6.11 and 6.12);
——The requirements for gas strength test are added (see 7.3.1);
——The methods for gas resistance test of diaphragm and low-temperature resistance test of diaphragm are modified (see 7.4.2 and 7.4.3; 7.4.2 and 7.4.3 of Edition 2011);
——The requirement that no intermediate static characteristic test be conducted when the applicable range of inlet pressure and outlet pressure of pressure regulator is too narrow is added (see 7.6.1.1);
——The inspection method for failure state is added (see 7.10);
——The test method for integrated shut-off device is added (see 7.11);
——The test method for integrated monitor is added (see 7.12);
——The test method for integrated release device is added (see 7.13);
——The test methods for torsion resistance and bending resistance of meter pressure regulator are added (see 7.14);
——the inspection rules are modified (see clause 8; clause 8 of Edition 2011);
——The marking and label of pressure regulator are modified (see 9.1; 9.1 of Edition 2011);
——The operating instructions of pressure regulator are modified and the requirements for providing noise and corresponding operating conditions are added (see 9.2; 9.2 of Edition 2011);
——The physical and mechanical properties of rubber materials as well as gas resistance are modified (see Annex A; Annex A of Edition 2011).
This standard was proposed by and is under the jurisdiction of the Ministry of Housing and Urban-Rural Development of the People's Republic of China.
The previous edition of this standard is as follows:
——GB 27790-2011.
City gas pressure regulator
1 Scope
This standard specifies terms, definitions and symbols, classification and labelling, structure and materials, requirements, test methods, inspection rules, marking, label and operating instructions as well as packaging, transport and storage of city gas pressure regulator (hereinafter referred to as pressure regulator).
This standard is applicable to the pressure regulators with a nominal diameter up to 400mm, an operating temperature range not exceeding -20℃~60℃ with the lower limit not less than the dew point temperature of the gas, and an inlet pressure up to 10.0MPa.
This standard is not applicable to the pressure regulators for liquefied petroleum gas in cylinders and those for dimethyl ether.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 150 (all parts) Pressure vessel
GB/T 191 Packaging - Pictorial marking for handling of goods
GB/T 229 Metallic materials - Charpy pendulum impact test method
GB/T 528 Rubber, vulcanized or thermoplastic - Determination of tensile stress-strain properties
GB/T 531.1 Rubber vulcanized or thermoplastic - Determination of indentation hardness - Part 1: Durometer method (Shore hardness)
GB/T 699 Quality carbon structure steels
GB/T 1047 Pipework components - Definition and selection of nominal size
GB/T 1173 Casting aluminium alloy
GB/T 1220 Stainless steel bars
GB/T 1239.2 Cold coiled helical springs technical specifications - Part 2: Compressions spring
GB/T 1348 Spheroidal graphite iron castings
GB/T 1591 High strength low alloy structural steels
GB/T 1681 Rubber - Determination of rebound resilience of vulcanizates
GB/T 1682 Rubber, vulcanized - Determination of low-temperature brittleness - Single test piece method
GB/T 1690 Rubber, vulcanized or thermoplastic - Determination of the effect of liquids
GB/T 3077 Alloy structure steels
GB/T 3191 Aluminium and aluminium alloys extruded bars, rods
GB/T 3280 Cold rolled stainless steel plate, sheet and strip
GB/T 3452.1 Fluid power systems - O-rings - Part 1: Inside diameters, cross-sections, tolerances and size identification code
GB/T 3452.2 Fluid power systems - O-rings - Part 2: Quality acceptance criteria
GB/T 3512 Rubber, vulcanized or thermoplastic - Accelerated ageing and heat resistance tests - Air-oven method
GB/T 4423 Copper and copper-alloy cold-drawn rod and bar
GB/T 6388 Transport package shipping mark
GB/T 7233.1 Steel castings - Ultrasonic examination - Part 1: Steel castings for general purposes
GB/T 7306.1 Pipe threads with 55 degree thread angle where pressure-tight joints are made on the threads - Part 1: Parallel internal and taper external threads
GB/T 7306.2 Pipe threads with 55 degree thread angle where pressure-tight joints are made on the threads - Part 2: Taper internal and external threads
GB/T 7759 (all parts) Rubber, vulcanized or thermoplastic - Determination of compression set
GB/T 7762 Rubber, vulcanized or thermoplastic - Resistance to ozone cracking - Static strain test
GB/T 9124.1 Steel pipe flanges - Part 1: PN designated
GB/T 9124.2 Steel pipe flanges - Part 2: Class designated
GB/T 9440 Malleable iron castings
GB/T 9443 Steel and iron castings - Liquid penetrant inspection
GB/T 9444 Steel and iron castings - Magnetic particle inspection
GB/T 9969 General principles for preparation of instructions for use of industrial products
GB/T 12224 General requirements for industrial steel valves
GB/T 12227 General purpose industrial valve - Specification of spheroidal graphite iron castings
GB/T 12228 General purpose industrial valves - Specification of carbon steel forgings
GB/T 12229 General purpose industrial valves - Specification of carbon steel castings
GB/T 12716 Pipe threads with the thread angle of 60 degrees where pressure-tight joints are made on threads
GB/T 13306 Plates
GB/T 13384 General specifications for packing of mechanical and electrical product
GB/T 13934 Rubber, vulcanized or thermoplastic - Determination of flex cracking and crack growth (De Mattia)
GB/T 15115 Die casting aluminium alloys
GB/T 17213.15 Industrial-process control valves - Part 8-3: Noise considerations - Control valve aerodynamic noise prediction method
GB/T 20801.5 Pressure piping code - Industrial piping - Part 5: Inspection and testing
GB/T 23934 Hot formed helical compression springs - Technical Requirement
GB/T 32249 Aluminum and aluminum-alloy die forgings, hand forgings and rolled ring forgings - General specification
GB/T 38343 Technical specification for flange joints installation
GB 50058 Code for design of electrical installations in explosive atmospheres
CJ/T 180-2014 Manually operated gas valves for gas installations of buildings
CJ/T 335-2010 Slam-shut valves and relief valves for city gas
HG/T 20592 Steel pipe flanges (PN designated)
HG/T 20615 Steel pipe flanges (Class designated)
JB/T 6440 Methods of radiographic examination for steel castings valves
JB/T 7248 Technical specification for low temperature service steel casting for valves
JB/T 7927 Valve cast steel visual quality requirements
JB/T 7944 Coiled helical springs - Sampling inspection
NB/T 47008 Carbon steel and alloy steel forgings for pressure equipment
NB/T 47009 Alloy steel forgings for low temperature pressure equipment
NB/T 47010 Stainless and heat-resisting steel forgings for pressure equipment
NB/T 47013 (all parts) Nondestructive testing of pressure equipments
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this standard, the following terms and definitions apply.
3.1.1
gas pressure regulator
equipment whose function is to automatically regulate the gas outlet pressure to maintain it within certain pressure range
3.1.2
series of pressure regulator
generic term for pressure regulators with the same design concept, similar structure but different nominal diameter
3.1.3
direct acting pressure regulator
pressure regulators which have a direct control by virtue of the outlet pressure variation over the actuator which drives the control members to move
Note: See Figure 1 for an example of the action principle of the direct acting pressure regulator.
Key:
1——setting element;
2——actuator;
3——diaphragm;
4——sensing line;
5——valve seats;
6——seat ring;
7——regulator body;
8——control member;
9——casing of actuator;
10——breather/exhaust line;
11——metallic partition;
1＋3——controller;
Figure 1 Example of direct acting pressure regulator
3.1.4
indirect acting pressure regulator
pressure regulators which control by virtue of the outlet pressure variation over the actuator which drives the control members to move after the amplification of the pilot
Note: See Figure 2 for an example of the indirect acting pressure regulator.
Key:
1——pilot;
2——process line;
3——actuator;
4——sensing line;
5——motorization chamber;
6——valve seats;
7——seat ring;
8——regulator body;
9——control member;
10——metallic partition;
11——casing of actuator;
Figure 2 Example of indirect acting pressure regulator
3.1.5
meter pressure regulator
pressure regulator installed in front of the user's gas meter, with a nominal diameter not greater than DN25 and a maximum inlet pressure not greater than 0.2 MPa
3.1.6
integrated monitor
pressure regulating unit connected in series with the working pressure regulator, which starts to operate when the outlet pressure of the pressure regulator exceeds the set range of the working pressure regulator to maintain the outlet pressure of the pressure regulator within the allowable range
3.1.7
nominal diameter of pressure regulator
nominal diameter of pressure regulator inlet, indicating pressure regulator dimensions.
3.1.8
nominal pressure
numerical marking code concerned to pressure, rounded to an integral
Note: In this standard, it is used to express the nominal pressure at inlet and outlet flange of the pressure regulators.
3.1.9
design pressure
pressure value which is used to determine strength of the casing or other parts at appropriate design temperature
3.1.10
inlet pressure range
pressure range within which the given accuracy class at pressure regulator inlet is guaranteed
Note: The same pressure regulator may have different inlet pressure ranges.
3.1.11
maximum inlet pressure
maximum inlet pressure value permissible within inlet pressure range
3.1.12
minimum inlet pressure
minimum inlet pressure value permissible within inlet pressure range
3.1.13
outlet pressure range
pressure range within which the given accuracy class at pressure regulator outlet is guaranteed
Note: The same pressure regulator may have different outlet pressure ranges, and the pressure regulator may obtain the required outlet pressure range by replacing certain parts.
3.1.14
maximum outlet pressure
maximum outlet pressure value permissible within outlet pressure range
3.1.15
minimum outlet pressure
minimum outlet pressure value permissible within outlet pressure range
3.1.16
reference conditions
gas state where the temperature is 15℃ and absolute pressure is 101.325 kPa
3.1.17
volumetric flow rate
gas volume in reference conditions which flows through the pressure regulator in unit time
Note: The unit is m3/h.
3.1.18
flow coefficient
air flow passed when the absolute pressure is opened fully at the critical condition where the inlet absolute pressure is 0.243kPa and the temperature is 15℃
Note: The unit is m3/h.
3.1.19
performance
expressing the outlet pressure as a function of the inlet pressure and volumetric flow rate
3.1.20
performance curve
graphic representation of the outlet pressure as a function of the volumetric flow rate by changing volumetric flow rate (from increase to decrease) in case of constant inlet pressure and adjustment condition
Note: This standard adopts the performance curve when the inlet temperature is 15℃.
3.1.21
family of performance curves
set of performance curves obtained at different inlet pressures in the same adjustment condition
3.1.22
set point
nominal outlet pressure of a family of performance curves of the pressure regulator
Note: The set point may be equal to the rated outlet pressure.
3.1.23
hysteresis band
difference between two outlet pressure values corresponding to the same volumetric flow rate when the volumetric flow rate increases and decreases on one performance curve
3.1.24
motorization pressure
gas pressure within high pressure chamber of pressure regulator actuator
3.1.25
stable conditions
conditions where the outlet pressure are gradually changing to a stable value after interference generation
3.1.26
accuracy
percentage of average value of the absolute values of maximum positive deviation and maximum negative deviation between actual outlet pressure and set point within operating range on the same family of performance curves to the set point
3.1.27
accuracy class
maximum permissible value of accuracy multiplied by 100
3.1.28
lock-up pressure
outlet pressure at zero volumetric flow rate on performance curve when the control member of pressure regulator is at a lock-up position
Note: The time from the volumetric flow rate at lock-up point to the zero volumetric flow rate shall be greater than the response time for locking up the pressure regulator.
3.1.29
lock-up pressure class
maximum permissible value of ratio of difference between actual lock-up pressure and set point to set point multiplied by 100
3.1.30
maximum accuracy flow rate
minimum one among the maximum flow rates capable of guaranteeing the given accuracy class for inlet pressure range under specified set point
3.1.31
minimum accuracy flow rate
maximum one among the minimum flow rate or the minimum flow rate in quiescent operation capable of guaranteeing the given accuracy class for inlet pressure range under specified set point
3.1.32
lock-up pressure zone
zone between zero flow rate and minimum flow rate on each corresponding performance curve of inlet pressure and set point (see Zone 1 in Figure 3)
Key:
p2——outlet pressure;
p1——inlet pressure;
AC——accuracy class;
SG——lock-up pressure class;
Q——volumetric flow rate;
Qmax,p1——maximum flow rate under p1;
p2s——set point;
Qmin,p1——minimum flow rate under p1;
1——lock-up pressure zone SZ.
Figure 3 Lock-up pressure zone (stable condition)
3.1.33
class of lock-up pressure zone
maximum permissible value of ratio of minimum flow rate to maximum flow rate multiplied by 100
3.1.34
class of lock-up pressure zone of family of performance curves
maximum permissible value of ratio of minimum accuracy flow rate to maximum accuracy flow rate on the family of performance curves multiplied by 100
3.1.35
operating temperature range
temperature range of medium and body in which the pressure regulator components and additional devices are capable of operating normally
3.1.36
control member
movable element installed in the flow passage of the pressure regulator, which is used for controlling the opening degree of the flow passage of the pressure regulator
3.1.37
fail close pressure regulator
pressure regulator that automatically closes or tends to close when the main diaphragm fails or the power system that moves the control member fails
3.1.38
fail open pressure regulator
pressure regulator that automatically opens or tends to open when the main diaphragm fails or the power system that moves the control member fails
3.1.39
integrated release device
self-actuated release unit installed on the pressure regulator body and, when the control pressure reaches the release pressure set value, releasing gas to the atmosphere with limited flow rate
3.1.40
integrated shut-off device
self-actuated shut-off device installed on the pressure regulator body
Note: It is characterized in that when the pressure regulator works normally, the integrated shut-off device is on, when the pressure at the outlet of the pressure regulator reaches the set value of shut-off pressure, the gas passage is automatically cut off by virtue of the gas pressure at the outlet of the pressure regulator, and the actuator is reset manually after troubleshooting the gas system.
3.2 Symbols
For the purposes of this standard, the symbols listed in Table 1 apply.
Table 1 Symbols and explanations
S.N. Symbol Unit Explanation
1 A % Accuracy
2 Amin % Elongation
3 AC — Accuracy class
4 AQ — Shut-off pressure accuracy class
5 Cg — Flow coefficient
6 Cgi — Flow coefficient under test conditions
7 Cgx — Flow coefficient of pressure regulator under partial opening
8 DN — Letter symbol before nominal diameter identification
9 d — Relative density of test medium
10 K1j — Shape coefficient under test conditions
11 K1 — Shape coefficient
12 m — Number of test conditions under subcritical flow condition in the flow coefficient Cg test
13 n — Number of test conditions under critical flow condition in the flow coefficient Cg test
14 p MPa Design pressure
15 p1 MPa Inlet pressure
16 p1av MPa Medium value between maximum inlet pressure and minimum inlet pressure
17 p1t Pa Pressure of test medium in the pressure-bearing chamber at the first measurement
18 p1max MPa Maximum inlet pressure
19 p1min MPa Minimum inlet pressure
20 p2 MPa Outlet pressure
21 p2c MPa Initial outlet pressure
22 p2t Pa Pressure of test medium in the pressure-bearing chamber at the second measurement
23 p2int MPa Initial outlet pressure between p2min and p2max
24 p2max MPa Maximum outlet pressure within outlet pressure range
25 p2min MPa Minimum outlet pressure within outlet pressure range
26 p2s MPa Set point
27 pa MPa或Pa Atmospheric pressure
28 pb MPa Lock-up pressure
29 pb1 MPa Pressure obtained by carrying out thermometric correction for lock-up pressure measured at the first time in the lock-up pressure test
30 pb2 MPa Pressure obtained by carrying out thermometric correction for lock-up pressure measured at the second time in the lock-up pressure test
31 pn Pa Reference pressure
32 pta MPa Actual value of shut-off pressure
33 pts MPa Set value of shut-off pressure
34
MPa Lock-up pressure measured at the second time in the lock-up pressure test
35 pmax MPa Maximum design pressure
36 Q m3/h Volumetric flow rate
37 Qi m3/h Calculated leakage of a pressure-bearing chamber
38 Qm m3/h Volumetric flow rate measured when pressure regulator inlet temperature is t1
39 Qmax m3/h Maximum flow rate
40 Qmax, p1min m3/h Maximum flow rate when inlet pressure is p1min
41 Qmax, p1 m3/h Maximum flow rate at a certain inlet pressure
42 Qmin m3/h Minimum flow rate
43 Qmin, p1 m3/h Minimum flow rate at a certain inlet pressure
44 Qmin, p1av m3/h Minimum flow rate when inlet pressure is p1av
45 Qmin, p1min m3/h Minimum flow rate at minimum inlet pressure
46 Qmin, p1max m3/h Minimum flow rate at maximum inlet pressure
47 QL m3/h Maximum test volumetric flow rate of a characteristic line
48 QR m3/h Maximum flow rate provided by test bench
49 SG — Lock-up pressure class
50 SZ — Class of lock-up pressure zone
51 SZp2 — Class of lock-up pressure zone of family of performance curves
52 t h Pressure-holding time
53 t1 ℃ Test medium temperature in front of pressure regulator
54 t1t ℃ Temperature of test medium within pressure-bearing chamber during the measurement for the first time
55 t2t ℃ Temperature of test medium within pressure-bearing chamber during the measurement for the second time
56 tb1 ℃ Pressure regulator outlet temperature measured for the first time in the lock-up pressure test
57 tb2 ℃ Pressure regulator outlet temperature measured for the second time in the lock-up pressure test
58 V m3 Volume of pressure-bearing chamber
59 △＋ MPa Positive deviation between actual value and set point of outlet pressure
60 △－ MPa Negative deviation between actual value and set point of outlet pressure
61 △p MPa Minimum differential pressure at inlet and outlet at which the accuracy class may be guaranteed by the pressure regulator
62 △t h Interval between two measurements
63 △ph Pa Hysteresis band
64 △pt Pa Corrected pressure drop
65 △pmax MPa Maximum differential pressure borne by diaphragm
66 δ5 % Elongation of steels
67 δp1 MPa Inlet pressure range
68 δp2 MPa Outlet pressure range
4 Classification and model
4.1 Classification
The classification of pressure regulators shall meet the requirements of Table 2.
Table 2 Classification of pressure regulators
S.N. Classification method Category
1 Working principle Action mode Direct acting, and indirect acting
Failure state Fail-open, and fail-close
2 Connection type Flange, and thread
3 Maximum inlet pressure/MPa 0.01, 0.2, 0.4, 0.8, 1.6, 2.0, 2.5, 4.0, 6.3 and 10.0
4.2 Model
4.2.1 Model preparation
Product model preparation shall meet the following requirements:
a) The model preparation of pressure regulators shall be in the following format:
b) The working principle code of pressure regulators shall meet the requirements of Table 3;
Table 3 Operating principle codes of pressure regulator
Operating principle code Operating principle
Action mode Failure state
Direct acting Indirect acting Fail open Fail close
Z1 √ - √ -
Z2 √ - - √
J1 - √ √ -
J2 - √ - √
ZB √ - √ -
Notes:
1. "√" indicates that it is applicable; "-" indicates that it is not applicable.
2 ZB represents the meter pressure regulator.
c) The nominal diameter of pressure regulator refers to the nominal diameter of inlet connection;
d) The maximum inlet pressure, p1max, is divided into 9 grades, i.e., 0.01MPa, 0.2MPa, 0.4MPa, 0.8MPa, 1.6MPa, 2.5MPa, 4.0MPa, 6.3MPa and 10.0MPa, with the pressure value in MPa marked.
e) As for the connection type, L is for threaded connection, and the code is omitted in case of flanged connection;
f) Custom numbers, including manufacturer-defined numbers, such as series of pressure regulator.
4.2.2 Example
Examples for the models of pressure regulators are as follows:
a) RTJ1-150/0.4-A, indicating a fail open indirect acting pressure regulator which has a nominal diameter of DN150, a maximum inlet pressure of 0.4 MPa and a custom number of A, and is subjected to flange connection;
b) RTZB-15/0.01 L, indicating a meter pressure regulator which has a nominal diameter of DN15 and a maximum inlet pressure of 0.01MPa and is subjected to threaded connection.
5 Structure and material
5.1 General requirements
5.1.1 Design pressure
5.1.1.1 Metallic pressure-bearing parts
The design pressure of metallic pressure-bearing parts (include metallic parts bearing pressure at normal operation or metallic parts bearing pressure after diaphragm and differential pressure seal fails) shall meet the following requirements:
a) When the metallic pressure-bearing parts are subjected to inlet pressure p1, their design pressure shall not be less than the maximum inlet pressure and shall not be less than 0.4 MPa;
b) When metallic pressure-bearing parts are protected by safety protection devices, and the pressure to which they are subjected after the diaphragm or differential pressure seal fails is less than the inlet pressure and greater than or equal to normal operating pressure, the design pressure of the metallic pressure-bearing parts shall not be less than 1.1 times the pressure borne by them after the failure of diaphragm or differential pressure seal, or the design pressure specified in Item a) may be adopted;
c) For pressure-bearing parts which are subjected to a pressure less than the normal operating pressure after the failure of diaphragm or differential pressure seal, the design pressure shall not be less than 1.1 times the maximum normal operating pressure, or the design pressure specified in Item a) may be adopted;
5.1.1.2 Metallic partition
The design pressure of metallic partition shall not be less than 1.1 times the difference between maximum pressure at high-pressure side and minimum pressure at low-pressure side, however the design pressure of metallic partition in the valve shall meet the requirements of 5.1.1.1a).
5.1.1.3 Diaphragm
The design pressure of diaphragm shall meet the following requirements:
a) When the maximum differential pressure, △pmax, borne by the diaphragm is less than 0.015 MPa, the design pressure of the diaphragm shall not be less than 0.02 MPa;
b) When 0.015 MPa≤△pmax<0.5 MPa, the design pressure of the diaphragm shall not be less than 1.33△pmax;
c) When △pmax≥0.5 MPa, the design pressure of the diaphragm shall not be less than 1.1△pmax and it shall not be less than 0.665 MPa.
5.1.2 Operating temperature range
The operating temperature ranges of the pressure regulators shall be -10℃~60℃ or -20℃~60℃.
5.2 Structure
5.2.1 Connection type at inlet and outlet
5.2.1.1 The connection between the pressure regulator and the upstream and downstream pipelines shall meet the following requirements:
a) The connection dimension and sealing surface type of the flange shall meet the requirements of GB/T 9124.1, GB/T 9124.2, HG/T 20592 or HG/T 20615.
b) Pipe threads shall only be used for pressure regulators with a nominal diameter not greater than DN50, and shall meet the requirements of GB/T 7306.1, GB/T 7306.2 or GB/T 12716.
5.2.1.2 The nominal pressure of the flange shall not be less than the design pressure of the pressure regulator body, and shall be selected from the following series of values: 0.6 MPa, 1.0 MPa, 1.6 MPa, 2.0 MPa, 2.5 MPa, 4.0 MPa, 5.0 MPa, 6.3 MPa, 10.0 MPa and 11.0 MPa.
5.2.1.3 The nominal pressure of the inlet and outlet flanges of the pressure regulator shall be the same.
Contents of GB 27790-2020
Foreword i
1 Scope
2 Normative references
3 Terms, definitions and symbols
3.1 Terms and definitions
3.2 Symbols
4 Classification and model
4.1 Classification
4.2 Model
5 Structure and material
5.1 General requirements
5.2 Structure
5.3 Materials
6 Requirements
6.1 Appearance
6.2 Strength of pressure containing part
6.3 Inspection for finished product of diaphragm
6.4 External seal
6.5 Performance
6.6 Flow coefficient, Cg
6.7 Adaptability at limit temperature
6.8 Durability
6.9 Failure state
6.10 Performance of integrated shut-off device
6.11 Performance of integrated monitor
6.12 Performance of integrated release device
6.13 Torsion resistance and bending resistance of meter pressure regulator
7 Test methods
7.1 General requirements
7.2 Appearance
7.3 Strength of pressure-bearing parts
7.4 Inspection of finished diaphragm
7.5 External seal
7.6 Performance
7.7 Flow coefficient Cg
7.8 Adaptability at limit temperature
7.9 Durability
7.10 Failure state
7.11 Integrated shut-off device
7.12 Integrated monitor
7.13 Integrated release device
7.14 Torsion resistance and bending resistance of meter pressure regulator
8 Inspection rules
8.1 Inspection classification
8.2 Inspection items
8.3 End-of-manufacturing inspection
8.4 Type inspection
8.5 Judging rules
9 Marking, label and operating instructions
9.1 Marking and label
9.2 Operating instructions
10 Packaging, transport and storage
10.1 Packaging
10.2 Transport
10.3 Storage
Annex A (Normative) Physical and mechanical properties of rubber materials and gas resistance
Annex B (Informative) Storage of rubber parts of pressure regulators
Annex C (Normative) Alternative method for determining flow coefficient of mass flow regulators
Annex D (Informative) Flow characteristic
Annex E (Informative) Noise
