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The following main changes have been made with respect to JB/T 4750-2003:
——the following changes have been made to the standard structure: Clause 6 "head", Clause 7 "opening and opening reinforcement for nozzles” and Clause 8 "flange” in the former standard are incorporated into Clause 6 “head, opening and flange” in this standard; the thermal physical property parameters and safety grouping of common refrigerants are adjusted from Annex C in the former standard to Clause 3 in this standard; Annex D in the former standard is adjusted to 5.3 in this standard; Annex E in the former standard is adjusted to Clause 8 in this standard;
——the “pressure vessels for refrigerant equipment” in 1.1 is modified as "pressure vessels for refrigerant equipment (including tubular heat exchangers, etc., hereinafter referred to as vessels)";
——1.4 “for the pressure elements of which structural dimension cannot be determined according to this standard, the following methods may be adopted for design after being evaluated and approved by the National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China (SAC/TC 262) and the National Technical Committee on Refrigeration & Air-conditioning Equipment of Standardization Administration of China (SAC/TC 238)” is added;
——in 3.4.2 c), “the design pressure on high-pressure side shall be higher than the saturation vapor pressure corresponding to the condensing temperature specified below” is modified as "the design pressure on high-pressure side shall be higher than the saturation vapor pressure corresponding to the condensing temperature (dew point temperature for mixed refrigerant) specified below"; "the possible maximum condensing temperature of refrigerant under normal operating condition should be checked according to Annex C" is modified as “the possible maximum condensing temperature of refrigerant under normal operating condition is shown in Table 1 (this table covers the properties of common refrigerant; the properties of other refrigerants may refer to the relevant refrigerant instruction manual)”;
——a brief description of safety grouping of refrigerant is added in Table 2;
——in 3.4.2 d), “the design pressure is generally determined by the saturation vapor pressure of the refrigerant at 38℃, and should be checked according to Annex C” is modified as “the design pressure is generally determined by the saturation vapor pressure of refrigerant at 38℃, see Table 1”; “Where the specified ambient temperature exceeds 38℃, the design pressure on low-pressure side is determined by the possible maximum pressure of refrigerant” is modified as “Where the ambient temperature may exceed 38℃, the design pressure on low-pressure side is determined by the maximum pressure of refrigerant”;
——“where the design temperature obtained by using the above method is not lower than 0℃ and not higher than 38℃, the design temperature on low-pressure side shall be 38℃" in 3.5.1.2 is modified as “where the design temperature obtained by using the above method is not lower than 0℃, the design temperature on low-pressure side shall not be lower than 38℃";
——the "and vessels with design pressure not greater than 1.0MPa” is deleted in 3.8.1 c);
——the corrosion allowances of copper, aluminum and their alloy in different corrosive environments are modified from 0.2, 0.1 and 0 to 0.1, 0.05 and 0 in Table 3;
——the safety coefficient of copper and aluminum is modified as 3 in Table 4;
——the requirements for vacuum test are added in 3.12;
——the requirement “The steels with other steel grades other than those specified in this clause and cast iron materials, if adopted, shall also meet the relevant requirements of Annex A” is added in 4.1.4;
——Q235B "shall not be used for vessels containing Group B3 refrigerant in Table 1" is added in 4.2.2.1;
——permissible stresses of Q245R thick plate (>60~100mm) and Q345R thick plate (>60~100mm and >100~120mm) are added in Table 6;
——the 16Mn thick-walled tube of 17~40mm is deleted in Table 8;
——the copper tube with designation of TP2 is added in Table 11; the mechanical properties of copper material in Table 11 and aluminum material in Table 12 are taken from JB/T 4755 and JB/T 4734 respectively;
——the requirements for tube plate used as support are added in 5.3.1.4;
——the requirements for calculation of non-circular tube flanges (square, waist-shaped, ellipsoidal, quincuncial, etc.) and those for use of standard tube flanges and pressure vessel flanges are added in 6.3;
——Clause 7 "design of components in special shape” is added;
——the requirement “where the cylinder diameter is greater than 600mm, GB 151 or other verified calculation methods are adopted for calculation” in the tube plate calculation is added in 8.1.2.1;
——the permissible deviation requirements for (steel/copper/ aluminum) heat exchange tubes in Tables E.4~E.6 in the former standard are deleted, and only those for tube orifice are reserved as Tables 22~24 in this standard, with the table name changed from “permissible deviation for (steel/copper or copper alloy/aluminum or aluminum alloy) heat exchange tubes and their orifices” to “permissible deviation for orifice of (steel/copper or copper alloy/aluminum or aluminum alloy) heat exchange tube plate”. The deleted permissible deviation requirements for the (steel/copper/aluminum) heat exchange tubes in such tables shall be expressed according to corresponding standard;
——the permissible deviation is consistent with that in GB 151 as indicated in Table 22, 8.1.7;
——the Equation (27) Bmin≥Bg-(0.05~0.15) is changed to Bmin≥Bg-(0.05~0.10) in 8.1.8;
——the tube diameter in wall thickness calculation equation is changed from do≤200mm to do≤57mm in 8.3.1;
——the requirements for the method of connection between the tube with outer diameter do>57mm~150mm and tube plate in 8.3.2.5 are deleted;
——"vessels containing Group B3 refrigerant in Table 1 as indicated in the drawing" is added in 9.5.1.1;
——"Classes II and III vessels containing Group A3 refrigerant in Table 1 as indicated in the drawing" are added in 9.5.1.2;
——the requirements for inspecting test pieces and specimens batch by batch other than set by set are deleted;
——“3) The technical grade of the ultrasonic testing is Grade B” is added in 9.6.4 b);
——requirements for vacuum test operation are added in 9.7.7;
——requirements for steel substitution are added in Annex A and those for Q235A.F substitution are deleted.
Clause 7 "design of components in special shape" and Clause 8 "main components of tubular heat exchanger" are identical to relevant contents of JIS B 8240-1986.
In Clause 6 “head, opening and flange”, requirements for inspection opening and non-circular tube flanges are proposed; in addition, the head, opening and opening reinforcement shall be designed according to relevant contents of GB 150.
Annexes A and B in this standard are normative while Annex C is informative.
This standard was jointly proposed by the Subcommittee on Stationary Pressure Vessels of National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China (SAC/TC 262) and the National Technical Committee on Refrigeration & Air-conditioning Equipment of Standardization Administration of China (SAC/TC 238).
This standard is under the jurisdiction of National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China (SAC/TC 262).
This standard is interpreted by the National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China (SAC/TC 262).
The previous edition of this standard is as follows:
——JB/T 4750-2003.
Pressure vessels for refrigerant equipment
1 Scope
1.1 This standard specifies the requirements for design, manufacturing, inspection and acceptance of pressure vessels for refrigerant equipment (including tubular heat exchangers, etc., hereinafter referred to as "vessels") with liquefied gas as refrigerant, design pressure not higher than 4.0MPa and design temperature not higher than 200℃.
1.2 The vapor compression refrigeration cycle and similar cycle (including heat pump) shall be adopted as the working cycle of refrigerant equipment.
1.3 This standard is not applicable to the generators of vessels with inner diameter (the diagonal of rectangular section) less than 150mm or volume less than 0.025m3, the shellless double-tube heat exchanger, the cooling coil and the direct-fired absorption refrigerant equipment.
1.4 For the pressure elements of which the structural dimension cannot be determined according to this standard, the following methods may be adopted for design after being evaluated and approved by the National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China (SAC/TC 262) and the National Technical Committee on Refrigeration & Air-conditioning Equipment of Standardization Administration of China (SAC/TC 238).
a) stress analysis, including finite element method;
b) comparative experience design by the comparable structure that have been used.
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 150 Pressure vessels
GB 151 Tubular heat exchangers
GB/T 244 Metallic materials - Tube - Flattening test
GB 536 Liquefied anhydrous ammonia
GB/T 699-1999 Quality carbon structure steel
GB/T 700-2006 Carbon structural steels
GB/T 711-2008 Hot-rolled quality carbon structural steel plates sheets and wide strips
GB 712-2000 Hull structural steel
GB 713-2008 Steel plates for boilers and pressure vessels
GB/T 985.1 Recommended joint preparation for gas welding, manual metal arc welding, gas-shield arc welding and beam welding
GB/T 985.2 Recommended joint preparation for submerged arc welding
GB/T 1226 General pressure gauge
GB/T 1348-2009 Spheroidal graphite iron castings
GB/T 1527 Drawn tube of copper and copper alloys
GB/T 1804-2000 General tolerances－Tolerances for linear and angular dimensions without individual tolerance indications
GB/T 3077-1999 Alloy structure steels
GB 3087-2008 Seamless steel tubes for low and medium pressure
GB/T 3098.1-2000 Mechanical properties of fasteners - Bolts, screws and studs
GB/T 3098.2-2000 Mechanical properties of fasteners - nuts - coarse thread
GB/T 3274-2007 Hot-rolled plates, sheets and strips of carbon structural steels and high strength low alloy structural steels
GB/T 4436-1995 Wrought aluminium and aluminium alloy tubes－Dimensions and deviations
GB/T 5117 Carbon steel covered electrodes
GB/T 5118 Low alloy steel covered electrodes
GB/T 5293 Carbon steel electrodes and fluxes for submerged arc welding
GB 6479-2000 Seamless steel tubes for high-pressure for chemical fertilizer equipments
GB/T 6893-2000 Aluminium and aluminium alloy cold drawn (rolled) seamless tubes
GB/T 7778 Number designation and safety classification of refrigerants
GB/T 8163-2008 Seamless steel tubes for liquid service
GB/T 8890-2007 Seamless copper alloy tube for heat-exchanger
GB/T 9119 Slip-on-welding plate steel pipe flanges
GB/T 9439-2010 Grey iron castings
GB 9948-2006 Seamless steel tubes for petroleum cracking
GB/T 14957 Steel wires for melt welding
GB/T 17791-2007 Seamless copper tube for air conditioner and refrigeration equipment
GB/T 20928 Seamless inner grooved copper tube
GB/T 25198 Heads for pressure vessels
NB/T 47008-2010 Carbon steel and alloy steel forgings for pressure equipments
NB/T 47014
(JB/T 4708) Welding procedure qualification for pressure equipment
NB/T 47015
(JB/T 4709) Welding specification for pressure vessels
NB/T 47016
(JB/T 4744) Mechanical property tests of product welded test coupons for pressure equipment
JB/T 4701 A-type socket-weld flange
JB/T 4702 B-type socket-weld flange
JB/T 4707 Stud bolts
JB/T 4712.1-2007 Vessel supports - Part 1: Saddle support
JB/T 4712.2-2007 Vessel supports - Part 2: Leg support
JB/T 4712.3-2007 Vessel supports - Part 3: Lug support
JB/T 4712.4-2007 Vessel supports - Part 4: Bracket support
JB/T 4730.2 Nondestructive testing of pressure equipment - Part 2: Radiographic testing
JB/T 4730.3 Nondestructive testing of pressure equipment - Part 3: Ultrasonic testing
JB/T 4730.4 Nondestructive testing of pressure equipments - Part 4: Magnetic particle testing
JB/T 4730.5 Nondestructive testing of pressure equipments - Part 5: Penetrant testing
JB/T 4730.6 Nondestructive testing of pressure equipments - Part 6: Eddy current testing
JB/T 4734-2002 Aluminium welded vessels
JB/T 4755-2006 Copper pressure vessels
JB/T 6918 The sintered metal and glass visual lens and liquid meter for refrigeration
JB/T 10503 Specification for high performance tubes for air conditioning and refrigeration field service
TSG R0004 Supervision regulation on safety technology for stationary pressure vessel
3 General requirements
3.1 Basic requirements
The design, manufacturing, inspection and acceptance of the vessels shall not only meet the requirements of this standard, but also meet those of relevant laws, regulations and safety technical codes issued in China.
3.2 Qualification and responsibility
3.2.1 The design and manufacturing organizations of the vessels shall have sound quality assurance system. The design organization shall hold Design License for Special Equipment (Pressure Vessels), and the manufacturing organization shall hold Manufacturing License for Pressure Vessels.
3.2.2 The design and manufacturing of the vessels under the jurisdiction of Supervision regulation on safety technology for stationary pressure vessel shall be under the supervision of the safety supervision organization of special equipment.
3.2.3 Responsibilities of design organization:
a) the design organization shall be responsible for the accuracy and completeness of design documents;
b) the design documents of vessels at least include strength calculation sheets, design drawings, manufacturing technical conditions and risk assessment report (applicable to Class III pressure vessels); the installation, operation and maintenance instructions shall also be included if necessary;
c) the general design drawing of vessels shall be stamped with the design licensing seal of pressure vessels;
d) the design organization shall preserve all design documents within the design service life of vessels.
3.2.4 Responsibilities of manufacturing organization:
a) the manufacturing organization shall manufacture in accordance with the requirements of design drawing; if the original design needs to be modified, written certificate document of the original design organization for modification agreement shall be obtained, and the modified parts shall be recorded in detail;
b) the inspection department of the manufacturing organization shall carry out various specific inspections and tests for the vessels according to the requirements of this standard and the drawing during and after manufacturing of vessels, propose inspection report and be responsible for the report accuracy and completeness;
c) the manufacturing organization shall at least preserve the following technical documents of each vessel product for future reference, and these documents shall be preserved for at least 7 years:
——manufacturing process drawing or manufacturing process card;
——product quality certificates;
——documents on welding process and heat treatment process of vessels;
——records on items for selection by the manufacturer in this standard;
——inspection records during and after the manufacturing;
——the original design drawings and completion drawings of vessels.
d) after obtaining the confirmation of the inspection organization on that the vessel quality meets the requirements of this standard and the drawings, the manufacturing organization shall fill in the product quality certificate and submit it to the user.
3.3 Scope of vessels
3.3.1 The vessels under this standard refer to the shells and the pressure parts and components and stressed elements connected to shells, see 3.3.2 for details.
3.3.2 Connection between the vessel and the external tube:
a) the groove end face of the first girth joint of welded connection;
b) the end face of the first threaded joint of threaded connection;
c) the first flange sealing surface of flange connection;
d) the first sealing surface of special connecting piece or tube fittings connection.
3.3.3 Stressed elements such as supports and lugs.
3.4 Pressure (gauge pressure, unless otherwise specified)
3.4.1 Working pressure
The possible maximum pressure on the vessel top during normal operation or shutdown of refrigerant equipment.
The high-pressure side and low-pressure side shall be the possible maximum pressure on the vessel top respectively during normal operation and shutdown of refrigerant equipment.
3.4.2 Design pressure
It refers to the set maximum pressure on the vessel top, which shall be taken as the design load condition together with the corresponding design temperature; it shall not be less than working pressure.
a) Where the vessel is composed of more than two pressure chambers and the pressures acting on each chamber are different, the design pressure shall be determined respectively according to the pressure of each chamber.
b) In order to ensure its working pressure not exceeding the design pressure of vessel, the charging capacity limit of refrigerant is as follows:
1) reservoir: the charging capacity of refrigerant liquid shall not exceed 80% of the vessel volume;
2) cascade refrigerant equipment: the charging capacity of refrigerant on the low-temperature side is determined by calculation.
c) Design pressure on high-pressure side
In the refrigeration cycle system, the part bearing condensing pressure due to the action of compressor belongs to the high-pressure side.
The design pressure on high-pressure side shall be higher than the saturation vapor pressure corresponding to the condensing temperature (dew point temperature for mixed refrigerant) specified below:
1) the possible maximum condensing temperature of refrigerant under normal operating condition is shown in Table 1 (this table covers the properties of common refrigerant; the properties of other refrigerants may refer to the relevant refrigerant instruction manual);
2) where the condensing temperature is higher than 65℃, the design pressure on high-pressure side shall be determined by the possible maximum condensing temperature of refrigerant.
d) Design pressure on low-pressure side
The part other than the high-pressure side in the refrigeration cycle system. The intermediate-pressure part of the intercooler of two-stage compression refrigerant equipment and the condensing evaporator with condensing temperature not higher than -15℃ in cascade refrigerant equipment also belong to the low-pressure side.
The design pressure on low-pressure side shall meet the following requirements:
1) the design pressure is generally determined by the saturation vapor pressure of refrigerant at 38℃, see Table 1;
2) where the ambient temperature may exceed 38℃, the design pressure on low-pressure side is determined by the maximum pressure of refrigerant.
Foreword i
1 Scope
2 Normative references
3 General requirements
4 Materials
5 Cylinder
6 Head, opening and flange
7 Design of components in special shape
8 Main components of tubular heat exchanger
9 Manufacturing, inspection and acceptance
Annex A (Normative) Supplementary requirements for materials
Annex B (Normative) Safety accessories
Annex C (Informative) Requirements for liquid ammonia in pressure vessels for steel ammonia refrigerant equipment and filling procedures
