This standard specifies the basic type, technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of liquid ammonia cylinder valves. This standard applies to valves on liquid ammonia cylinders with a working temperature of -40 to 60°C and a nominal working pressure of 3MPa. This standard does not apply to valves on liquid ammonia equipment. GB 17877-1999 Liquid Ammonia Cylinder Valve GB17877-1999 Standard download decompression password: www.bzxz.net

GB 17877 --- 1999
In order to improve the design and manufacturing level of gas cylinder valves in my country and ensure the safety and reliability of the use of liquid ammonia cylinder valves, this standard specifies the basic types, technical requirements, and test methods of liquid ammonia cylinder valves in accordance with GB15382-1994 "General Technical Conditions for Gas Cylinder Valves". This standard is proposed and managed by the National Technical Committee for Gas Cylinder Standardization. This standard was drafted by Zhejiang Xiangshan Valve Factory. The main drafters of this standard: Shi Jingen, Chen Dachang, Weng Guodong, Cai Yanxin, Lu Shibiao 156
1 Scope
National Standard of the People's Republic of China
Liquid Ammonia Cylinders
Valves for liquid ammonia cylindersGB 17877- 1999
This standard specifies the basic types, technical requirements, test methods, test rules, marking, packaging, transportation and storage of liquid ammonia cylinder valves (hereinafter referred to as valves).
This standard applies to valves on liquid ammonia bottles with a working temperature of -40 to +60°C and a nominal working pressure of 3MPa. This standard does not apply to valves on liquid nitrogen equipment. 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T699-1988 Technical conditions for high-quality carbon structural steel GB/T7307-1987 Pipe threads for non-threaded seals GB8335-1998 Special threads for gas cylinders
GB/T8336-1998 Special thread gauges for gas cylinders GB/T10922--1989 Pipe thread gauges for non-threaded seals HG/T 2902-1997
JC 68-—1982(1996)
3 Basic types and connection dimensions
Polytetrafluoroethylene resin for molding
Oil-impregnated asbestos packing
3.1 The basic types and connection dimensions of the valve are as specified in Figure 1. 3.2 The inlet thread of the valve is PZ27.8 tapered thread, and the outlet thread of the valve is G1/2. 3.3 The nominal diameter of the valve is 6mm.
4 Technical requirements
4.1 Materials
The materials used for the valve body and main parts shall comply with the provisions of Table 1. When other materials are used, their performance shall not be lower than the materials specified in this standard and shall be resistant to liquid ammonia corrosion.
Approved by the State Administration of Quality and Technical Supervision on October 10, 1999 and implemented on June 1, 2000
Parts name
Safety cap, pressure cap
Seal cap
4.2 Processing requirements
Provisions.
GB 17877—1999
1—Valve stem 2~—Pressure cap; 3—Valve body; 4—Safety cap Figure 1
High-quality carbon structural steel
Oil-impregnated asbestos packing
Polytetrafluoroethylene
Standard No.
GB/T699
HG/T 2902
The valve body must be forged, and there must be no macroscopic cracks, pores, wrinkles, inclusions and incomplete filling that may damage the valve performance on the surface. The inlet thread of the valve shall comply with the provisions of GB8335; the outlet thread shall comply with the B-level accuracy of GB/T7307~-1987. 4.2.3 The surfaces of the valve body and other metal parts shall be treated with anti-corrosion. 4.3 Performance requirements
4.3.1 Opening and closing torque
Under the nominal working pressure, the opening and closing torque of the valve should not be greater than 10N·m. 4.3.2 Air tightness
Under the nominal working pressure, the valve should be leak-free when it is closed or opened at any time. 4.3.3 Vibration resistance
Under the nominal working pressure, the valve should be able to withstand vibration with an amplitude of 2mm and a frequency of 33Hz. All valve connections should be tight and leak-free. 4.3.4 Temperature resistance
GB 17877 - 1999
Under the nominal working pressure, the valve should be leak-free within the temperature range of -40 to +60°C. 4.3.5 Pressure resistance
Under 2 times the nominal working pressure, the valve should be free of leakage and other abnormal phenomena. 4.3.6 Durability
Under the nominal working pressure, the valve should be opened and closed 1000 times in full stroke without leakage or other abnormal phenomena. 5 Inspection and test methods
5.1 Appearance inspection
The valve body surface shall be inspected by visual inspection and shall comply with the provisions of 4.2.1. 5.2 Inlet and outlet thread inspection
The size and accuracy of the valve inlet and outlet threads shall be inspected with a special gauge and shall comply with the provisions of 4.2.2. The gauge for inspecting the inlet thread shall comply with the provisions of GB/T8336, and the gauge for inspecting the outlet thread shall comply with the provisions of GB/T10922. 5.3 Opening and closing torque test
Install the valve on a special device, close the valve with the torque specified in 4.3.1, fill air or inert gas from the valve inlet to the nominal working pressure, immerse in water and observe for 1 minute. During this period, there should be no leakage at the valve outlet; then lift the valve out of the water, open the valve under air pressure and measure the opening torque. This torque should comply with the provisions of 4.3.1. 5.4 Air tightness test
Install the valve on a special device, close the valve with the torque specified in 4.3.1, fill air or inert gas from the valve inlet to the nominal working pressure, immerse in water and observe for 30 seconds. The result should comply with the provisions of 4.3.2; then block the outlet, make the valve in any open state, immerse in water and observe for 30 seconds. The result should comply with the provisions of 4.3.2. 5.5 Vibration resistance test
Install the valve on a special device, close the valve with the torque specified in 4.3.1, and fill the valve with air or inert gas from the valve inlet to the nominal working pressure; then install the special device on the vibration test bench and vibrate in any direction for 30 minutes. The result should meet the requirements of 4.3.3. 5.6 Temperature resistance test
Install the valve on a special device, close the valve with the torque specified in 4.3.1, fill the valve with air or inert gas from the valve inlet to the nominal working pressure, and place it in a thermostatic box at a temperature of 60°C ± 2°C for 1.5 hours. It should meet the requirements of 4.3.4; then block the valve outlet, make the valve in any open state, and place it in a thermostatic box at a temperature of 60°C ± 2°C for 1.5 hours. It should meet the requirements of 4.3.4. According to the above requirements, the valve is placed in a thermostatic box with a temperature of -40℃±2℃, and kept warm for 1.5 hours in the open and closed states. It should comply with the provisions of 4.3.4. 5.7 Pressure resistance test
Install the valve on a special device, block the valve outlet, make the valve in any open state, fill the water pressure from the air inlet to 2 times the nominal working pressure, and continue for 3 minutes. The result should comply with the provisions of 4.3.5. 5.8 Durability test
Install the valve on a special device, block the valve outlet, fill the air or inert gas from the air inlet to the nominal working pressure, and then open and close the valve at a rate of 8 to 15 times per minute and an opening and closing torque of 10N·m. The result should comply with the provisions of 4.3.6 of this standard. After the test, carry out the test specified in 5.4. 6 Inspection rules
6.1 Factory inspection
Products shall pass the factory inspection. The factory inspection shall be carried out one by one. The inspection items are: a) Appearance inspection shall comply with the provisions of 5.1; b) Inlet and outlet thread inspection shall comply with the provisions of 5.2; c) Air tightness test shall comply with the provisions of 5.4. 6.2 Type inspection
6.2.1 Type inspection must be carried out in the following cases: a) When the valve is designed, trial-produced, or identified;
GB 17877—1999
b) When there are major changes in the design, materials, or process of the valve; c) It must be carried out once a year;
d) When resuming production after a suspension of more than 6 months. 6.2.2 Five samples for type inspection shall be drawn from the qualified batches that have recently passed the factory inspection (each batch shall not exceed 3,000). The items for type inspection shall be as specified in Table 2. During the inspection process, if one sample does not meet the requirements of a certain item of this standard, double sampling should be carried out and all items should be re-inspected. If there are still items that fail to meet the requirements, the batch of products will be considered unqualified. Table 2
Test piece group numberwwW.bzxz.Net
7 Marking, packaging, transportation and storage
7.1 Marking
Inspection sequence
The valve should have the following clear and durable markings: a) Valve model;
b) Valve nominal working pressure;
c) Manufacturer's trademark;
d) Production date or batch number.
7.2 Packaging
7.2.1 The water in the valve should be removed before packaging. Inspection items
.5.1 Appearance inspection
5.2 Inlet and outlet thread inspection
5.3 Opening and closing torque test
5.4 Air tightness test
5. 5 Vibration resistance test
5.6 Temperature resistance test
5.1 Appearance inspection
5.2 Inlet and outlet thread inspection
5.3 Opening and closing torque test
5.4 Air tightness test
5.6 Temperature resistance test
5.7 Pressure resistance test
5.1 Appearance inspection
5.2 Inlet and outlet thread inspection
5.4 Air tightness test
5. 8 Durability test
7.2.2 Each product should be packed separately. When packing, the valve should be kept clean and the inlet and outlet threads should be kept free from damage. 7.2.3 Each product shall be accompanied by a product certificate when packaged, which shall include the following contents: a) Manufacturer’s name; b) Valve name and model; sampling number, pieces; c) Valve nominal diameter; d) Valve nominal working pressure; e) Factory inspection mark; f) Inspection date. 7.2.4 The following marks shall be on the packaging box: a) Manufacturer’s name: b) Valve name and model; c) Necessary operation requirement symbol; d) Quantity and gross weight; e) Volume (length × width × height); 1) Factory year and month or batch number.
GB 17877 -- 1999
7.2.5 The packing box should be accompanied by a packing list, which should include the following information: a) Manufacturer's name;
b) Valve name and model;
c) Quantity, net weight and gross weight;
d) Packing personnel's stamp or signature;
e) Packing date.
7.3 Transportation and storage
7.3.1 The products should be handled with care during loading and unloading to prevent heavy pressure, collision and moisture. 7.3.2 The products should be stored in a ventilated, dry and clean room. 161
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