Some standard content:
Mechanical Industry Standard of the People's Republic of China
Stop valve for refrigeration equipment
Subject content and scope of application
JB/T 7245--94
This standard specifies the type and basic parameters, technical requirements, test methods, inspection rules, packaging, marking and storage of stop valves for refrigeration equipment.
This standard applies to general-purpose pipeline stop valves for refrigeration equipment with nominal pressure PN≤3MPa, nominal diameter DN4~~300mm, temperature 50~~160C and R12.R22, R502 and R717 as refrigerants (hereinafter referred to as stop valves). Refrigeration stop valves for other purposes shall be implemented as a reference.
Cited standards
G13/T13306 Label
JB3/Z224 Stop valve static pressure life test procedure JB/T4119 Refrigeration solenoid valve
3 Types and basic parameters
3.1 Type
3.1.1 Stop valves are divided into two types according to the passage type: straight-through type and right-angle type. 3.1.2 Stop valves are divided into five types according to the connection type: threaded, flanged, flared pipe, brazing and butt welding. 3.2 Model
The stop valve model consists of uppercase Chinese phonetic letters and Arabic numerals, and the representation method is as follows: ■
Model marking example:
Nominal pressure: expressed in numbers, MPa
Connection type code: L for thread, K for flared pipe, F for flange, Q for brazing, D for butt welding (two codes are used for different interfaces at both ends) Passage type code: Straight-through type is not represented, right-angle type is represented by "Nominal diameter: expressed in numbers, mm
Stop valve code
Applicable working fluid code: Freon is represented by F, ammonia is represented by A. FJ6JKQ-2 indicates that the inlet is flared, the outlet is brazed, right angle, used for Freon refrigerant, the nominal pressure is 2MPa, and the nominal diameter is 6mm. AJ100F-25 indicates flange connection, straight-through type, used for nitrogen refrigerant. The nominal pressure is 2.5MPa and the nominal diameter is 100mm. The stop valve approved by the Ministry of Machinery Industry of the People's Republic of China on July 18, 1994 and implemented on July 1, 1995. 3.3 Basic parameters 3.3.1 Nominal pressure PN is 2.0.2.5.3MPa. 3.3.2 Nominal diameter IN a. Diameter of valve for copper pipe connection:
JB/T 7245--94
4.6.8,10,(13),(15),(16)-(19).20,25.32.40,50,65,80 mms Note: The diameters in brackets are not recommended. b. Diameter of valve for steel pipe connection:
6,10,15.20.25,32,40,50,65.80,100,125,150,200,250,300 mm3.3.3 For pipe sizes, see Appendix A (reference). 4 Technical requirements
4.1 General requirements
Stop valves shall comply with the requirements of this standard and be manufactured in accordance with drawings and technical documents or agreements approved by the prescribed procedures. 4.2 Materials
4.2.1 The materials of the valve body and main parts shall have the certificate of chemical composition and physical properties. 4.2.2 The materials of the valve body and main parts shall meet the following requirements: The materials of the valve body and main parts shall be compatible with the temperature, pressure and refrigerant used; a.
The materials of the valve body and main parts shall meet the performance and strength requirements of the stop valve: The valve stem material shall not corrode under humid air conditions and maintain its metallic luster. c.
4.2.3 The sealing material shall meet the following requirements: a.
Capacitance;
The various non-metallic sealing materials used in the valve shall be resistant to changes in temperature and pressure and meet the corresponding standards; The various non-metallic sealing materials used in the valve shall have good compatibility with the refrigerant, lubricant, corresponding metal materials and their mixtures; The valve shall be able to maintain good airtightness during use. 4.3 Structure
4.3.1 The valve stem rotates clockwise to close, and the valve shall be flexible and reliable to open and close under standard conditions, and the valve cover shall not rotate with the opening and closing operation.
The stop valve body connected by the flared pipe joint should have a wrench clamp and its substitute. 4.3.3 The stop valve for Freon should generally be equipped with a safety cap. 4.3.4 For safety and maintenance, the stop valve is generally equipped with an upper seal. 4.3.5 The stop valve with an upper seal should be able to tighten and replace the packing in the compressed state, and the valve stem should be prevented from rotating out when the packing is replaced. 4.4 Quality of internal and external surfaces
4.4.1 The internal and external surfaces of the casting should not have defects such as pores, flash, sand adhesion, sand inclusion, cracks, etc. that hinder use. The internal and external surfaces of the forging should not have defects such as interlayers, folds, flash, cracks, etc. that hinder use. 4.4.2t
4.4.3 The internal and external surfaces of the welded parts should not have defects such as incomplete penetration along the entire length of the weld. The machined surface should not have defects such as burrs, dents, scars, and different processing precision. 4.4.4wwW.bzxz.Net
5 The edges or corners without dimension shall be properly chamfered or rounded. 4.4.5
The refrigerant passage shall be smooth and clean. 4.5 Performance
4.5.1 The pressure resistance of the valve body: The valve body shall not have abnormal deformation and leakage at 1.5 times the nominal pressure. 2 Air tightness: The sealing of the closing seal, upper seal and sealing cap of the stop valve shall not be short under the nominal pressure and the torque specified in the design. 4.5.2
JB/T 7245- -94
4.5.3 Durability: The stop valve shall still meet the requirements of 4.5.2 after 6500 times of full stroke opening and closing under the design closing torque. 4.5.4 High temperature resistance: The stop valve used on the high pressure and high temperature side should be able to work normally at 50~~160C. 4.5.5 Low temperature resistance: The stop valve used on the low pressure and low overflow side should be able to work normally at 50~160C. 4.5.6 Flow capacity: The flow value expressed in m/h when water flows through the stop valve to produce a pressure drop of 0.1MPa. 4.6 Warranty period
If the user complies with the provisions of the product manual, within 18 months from the date of shipment from the manufacturer, if the stop valve is damaged or cannot work normally due to poor manufacturing quality, the manufacturer shall be responsible for repair or replacement. 5 Test method
5.1 Internal and external surface quality
Inspect by visual inspection.
5.2 Valve body pressure resistance strength test
5.2.1 Close the valve inlet and outlet, press the packing gland, make the opening and closing parts in the half-open position, fill the valve body with liquid (water or lubricating oil), exhaust the air, and then gradually pressurize to 1.5 times the nominal pressure, maintain the pressure for more than 1 minute, the shell should have no leakage or abnormal deformation. After the test, it should be dried.
5.2.2 When there is a safety protection device, the forged valve can be tested for strength with gas (air or nitrogen) instead of liquid at 1.25 times the nominal pressure. 5.3 Air tightness test
5.3.1 Put the stop valve into water in the open state, pressurize the air in the valve body to the nominal pressure, and maintain the pressure for more than 30: There should be no leakage on the face and other parts of the stop valve.
5.3.2After closing the stop valve under the torque specified in the design, put it into the water, then gradually add air to the nominal pressure from the inlet of the stop valve, keep the pressure for more than 30 seconds, and check that there should be no gas leakage from the valve seal and each connection. 5.3.3For the stop valve with upper seal, first press the valve stem against the upper seal seat (fully open state) according to the torque specified in the design, then loosen the packing gland, and in the free state, gradually pressurize the air in the shell to the nominal pressure, keep the pressure for more than 30 seconds, and check that there should be no leakage in the upper seal. 5.3.4For the stop valve with cap, first put the valve stem in the open position, then loosen the packing gland, and in the free state, gradually pressurize the air in the valve body to the sealing performance test pressure, keep the pressure for more than 30 seconds, and check that there should be no leakage at the connection between the cap and the valve cover. 5.3.5The air tightness test should be carried out after the strength test. 5.4Durability test
Carry out the life test according to the provisions of JB/Z224. 5.5 High temperature resistance test
Install the valve on a special fixture, the valve is in a closed state, fill it with nitrogen or air from the inlet end and pressurize it to 0.7 times the nominal pressure of the valve: then put it in a high temperature box at 150-160°C, keep it for 4 hours, take it out, cool it to room temperature, there should be no leakage. 5.6. Low temperature resistance test
Install the valve on a special fixture, the valve is in a closed state, fill it with nitrogen or air from the inlet end and pressurize it to 0.2 times the nominal pressure of the valve: then put it in a low temperature box at 45-50°C, keep it for 4 hours, take it out, heat it to room temperature, there should be no leakage. 5.7 Flow capacity test
Perform according to Article 6.13 of JB/T4119.
6 Inspection rules
6.1 The items for factory delivery, sampling and type inspection of stop valves shall be in accordance with the provisions of Table 1: 153
Inner and outer surface quality
Strength test
Air tightness test
Flow capacity
Factory inspection
Each stop valve shall be subject to factory inspection.
6.3 Sampling inspection
IB/T7245—94
Sampling inspection
Type inspection
Products produced in batches shall be subject to sampling inspection to check the stability of the production process. 6.3.2
Technical requirements
The number of products of the same model in a year shall be regarded as an inspection batch. The sampling time shall be evenly distributed in a year. The sampling plan shall be in accordance with the provisions of Table 2
>50100
>100～500
6.4 Type inspection
Sample size II
Qualified judgment number 1.
Test method
Unqualified judgment number R.
6.4.1 Newly manufactured stop valves and those with major changes in design, process or materials that may affect product performance shall be subject to type inspection. Each test sample shall not be less than 5 pieces.
6.4.2 The results of the flow capacity test shall be recorded in the product manual. 7
Marking, packaging and storage
Each stop valve shall have the marking of nominal pressure and nominal diameter in an obvious position. The size and technical requirements of the label shall comply with the provisions of 7.1
GB/T13306
7.2 The stop valve shall be accompanied by the following documents:
Product certificate;
b. Product manual;
Packing list.
7.3 The stop valve and technical documents shall be wrapped in plastic film and placed in the packaging box. The gap between the product and the packaging box shall be filled with cushioning materials. 7.4 The stop valve shall be placed in a ventilated and dry place and shall not be stored in the open air. 154
A1 See Table A1 for recommended pipe sizes.
Nominal diameter
Additional instructions:
JB/T724594
Appendix A
Connection size
(reference)
Copper pipe connection size
Outer diameter mmx wall thickness mm
This standard was proposed by the Hefei General Machinery Research Institute of the Ministry of Machinery Industry and is under the jurisdiction of Nominal diameter
This standard was drafted by Shaoxing Refrigeration Equipment Factory and Shaoxing Chunhui Refrigeration Equipment Co., Ltd. The main drafters of this standard are Zhang Jiarui, Xu Xiaojuan, and Gu Qigang. Steel pipe connection size
Outer diameter mx wall thickness mn
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