Some standard content:
Mechanical Industry Standard of the People's Republic of China
Cutting Torches for Gas Cutting Machines
1 Subject Content and Scope of Application
JB 5101-91
This standard specifies the type, structure, technical requirements, test methods and inspection rules of cutting torches for gas cutting machines. This standard is applicable to cutting torches for various gas cutting machines for cutting carbon steel and low alloy steel. The gas used is oxygen and acetylene, liquefied petroleum gas, coal gas, natural gas and other combustible gases. The cutting thickness is 5 to 300 mm. 2 Reference standards
GB 5107
Hose connector for welding and cutting
GB5108 Isobaric welding torch and cutting torch
GB5110 Injection and suction cutting torch
GB 10860
Quick cutting nozzle
ZBJ33001 Trolley-type flame cutting machine
3 Terms
3.1 Backfire
Flame enters the cutting torch with a popping sound. Whether the flame is extinguished or reignites in the nozzle, it is considered backfire. 3.2 Continuous backfire
Flame enters the cutting torch and causes continuous burning in the cutting torch. It continues to burn in the cutting torch with a popping sound and a flowing hissing sound. It is considered continuous backfire.
3.3 Reflux
Reflux refers to the flow of higher pressure gas into a lower pressure gas pipeline. If the nozzle is clogged, this phenomenon may occur. 4 Type and structure
4.1 According to the general type of the mixed system, the jet suction cutting torch and the isobaric cutting torch are divided. 4.1.1 The general structure of the jet suction cutting torch for gas cutting machine is shown in Figure 1, and the matching angle of the connection between the cutting torch and the cutting nozzle is shown in Figure 2. L
Figure 1 Structure of the jet suction cutting torch
Approved by the Ministry of Machinery and Electronics Industry of the People's Republic of China on July 15, 1991 17
Implemented on July 1, 1992
JB 5101—91
Figure 2 Joint of the jet suction cutting torch and the cutting nozzle
4.1.2 The general structure of the isobaric cutting torch for gas cutting machine is shown in Figure 3, and the matching angle of the connection between the cutting torch and the cutting nozzle is shown in Figure 4. H
Figure 3 Isobaric cutting torch structure
30°+5
Figure 4 Isobaric cutting torch and cutting nozzle joint
5 Basic dimensions of cutting torch
5.1 Cylinder diameter D
Diameter D: 28_8.13mm, 30-0.1amm32.16mm, 350.16mm. 5.2 Cylinder length L
Cylinder length L: 50, 100, 150, 250, 400rmm. 5.3 Rack
The rack module is 1.25, and the rack width b is 8-0.2mm. 5.4 The distance H from the rack index line to the center line of the cylinder is shown in the following formula and Figure 5. H-
Tooth root height, mm;
Where: h\_
Rack width, mm.
+2+h
30°+5
5.5 Pipe joint
JB5101-91
Figure 5 Schematic diagram of rack indexing line to column center line When the column diameter D of the cutting torch is equal to 28mm and 30mm, the pipe joint is M12×1.25; when D is equal to 32mm and 35mm, the pipe joint is M16×1.5. Where threaded connection is required, it shall comply with the provisions of GB5107. 6 Technical requirements
6.1 Under the oxygen working pressure specified in Article 2.2 of GB5110, when the gas pressure is 0.006~0.008MPa, the visible cutting oxygen flow length in the flame of the suction cutting torch shall reach the cutting oxygen flow length value specified in Article 3.1 of GB5110. 6.2 Under the oxygen working pressure specified in Article 1.4 of GB5108, when the gas pressure is 0.02-0.05MPa, the visible cutting oxygen flow length in the flame of the isobaric cutting torch shall reach the cutting oxygen flow length value specified in Table 4 of Article 1.4 of GB5108. 6.3 When using a fast cutting nozzle, the gas pressure and the visible cutting oxygen flow length in the flame shall comply with the provisions of GB10860. 6.4 Each gas valve shall ensure that the gas path can be closed flexibly and the flow rate can be adjusted evenly. 6.5 The flame of the cutting torch shall burn stably. The flame shape shall be uniform and symmetrical, and turbulence, eccentricity, backfire and gas reflux are not allowed. The visible cutting oxygen flow is not allowed to be deflected. When the wind speed is 10m/s and blows vertically to the flame, the flame core shall remain stable. 6.6 All connections and gas valves of the cutting torch are not allowed to leak at the following intake pressures: a. In the oxygen passage, the maximum working pressure of oxygen is increased by 50%, but the maximum is 1.2MPa. b. The pressure in the gas and mixed gas passages is 0.25MPa. 6.7 All gas passage parts of the cutting torch shall be made of corrosion-resistant materials, and acetylene passage parts shall not be made of alloys with a content greater than 70%. 6.8 The fit between the hose connector and the rear connector of the cutting torch shall ensure airtightness and interchangeability. 6.9 The sealing thread fit of the cutting torch shall have an adjustment margin of 1 to 3 pitches. 6.10 Before assembly, all gas passage parts must be degreased. 6.11
The gas flow rate of the cutting torch shall be specified by the manufacturer in the instruction manual. 6.12 The appearance of the cutting torch shall be beautiful and tidy, without obvious mechanical damage, bending and surface defects. Test methods and inspection rules
7.1 Test methods
7.1.1 Cutting oxygen flow length test
Under the gas pressure specified in this standard, adjust the flame to the normal working state, that is, neutral flame, open the cutting oxygen valve, and measure the visible cutting oxygen flow length.
7.1.2 Combustion stability test
Under the gas pressure specified in this standard, adjust the flame to the normal working state, that is, the neutral flame. After stabilization for 30 seconds, make the flame perpendicular to the wind direction and place it at a wind speed of 10m/s. If the flame core of the cutting torch can burn normally within 10 seconds, it is qualified; if the flame core jumps, extinguishes or flashes back, it is allowed to repeat the test twice. If the flame core can burn normally, it is still qualified. 7.1.3 Air tightness test
Under the pressure specified in Article 6.6 of this standard, the cutting torch is passed with oil-free gas. With the gas valve closed and open, it is kept in water for 20 seconds. There should be no bubbles escaping from each gas valve and all joints. 7.1.4. Anti-flashback test
The test device is shown in Figure 6.
L=5×L,+4×Lz+20
Li=1. 25+1. 75Xdz
Lz=0. 50+0. 75Xdz
Center of rotation
Figure 6 Tempering test device
7.1.4.1 Test conditions
The bottom surface of the cutting nozzle is parallel to the surface of the copper plate with grooves, and the contact pressure between the cutting torch and the copper plate is F=5N. The rotation speed of the copper plate is n-5r/min, and the test radius is r=165mm.
7.1.4.2 Procedure
After ignition, adjust to neutral flame. After 30s, place the cutting torch on the rotating copper plate. During the test, it is not allowed to adjust the flame. Extinguish the flame during rotation, and re-ignition is allowed.
7.1.4.3 Evaluation
If the copper plate rotates 5 circles without continuous tempering, the test is qualified. After at least 2 rotations, 30 fire extinguishings occur without continuous tempering, the test is qualified.
The cutting nozzle and cutting torch shall be tested twice at room temperature without continuous tempering. Each rotation is 5 circles. The cutting nozzle and cutting torch shall be cooled when the test is repeated.
7.1.5 Test to prevent gas backflow
The test is carried out with oil-free compressed air or nitrogen. 7.1.5.1 Test to prevent oxygen backflow into the combustible gas pipeline. The test apparatus is shown in Figure 7.
a. Procedure
JB 5101-91
Fully open the gas and preheating oxygen valves, close the cutting oxygen valve, adjust the oxygen pressure to twice the pressure specified by the manufacturer, and record the pressure value of the gas pipeline.
b. Evaluation
If the recorded pressure value is lower than 0.5 times of the minimum fuel gas pressure value specified by the manufacturer for the model of cutting torch nozzle, the requirement of preventing oxygen from flowing back into the combustible gas pipeline is qualified. Pressure gauge connected to the oxygen pipe
Valve fully opened
Compressed air cylinder
Pressure gauge connected to the combustible gas pipe
Figure 7 Test device for preventing oxygen from flowing back into the fuel gas pipeline 7.1.5.2 Test for preventing combustible gas from flowing back into the oxygen pipeline: The test device is shown in Figure 8.
Pressure gauge connected to the preheating oxygen pipe
Compressed air bottle
Valve fully open
Pressure gauge connected to the gas pipeline
Figure 8 Test device to prevent gas from flowing back to the oxygen pipeline a.
Fully open the gas valve and preheating oxygen valve, close the cutting oxygen valve, and adjust the pressure of the gas pipeline to twice the maximum required by the manufacturer for the cutting nozzle (the maximum test pressure is 0.15MPa), record the pressure value of the oxygen pipeline. b. Assessment
If the recorded pressure value is lower than 0.5 times the minimum oxygen pressure value required by the manufacturer for this type of cutting nozzle, the test to prevent the gas from flowing back into the oxygen pipeline is qualified. bZxz.net
7.2 Inspection rules
JB 5101—91
7.2.1 The appearance quality shall be inspected one by one and shall comply with the provisions of Article 6.12 of this standard. 7.2.2 The air tightness test and the cutting oxygen flow length test shall be inspected one by one. 7.2.3 The sampling quantity for the combustion stability test, the anti-backfire test, the gas backflow prevention test and the connection size test shall be 10%, but at least 3 pieces shall be sampled for each batch.
7.2.4 During the random inspection, if there are unqualified items, double sampling shall be carried out for re-inspection of the unqualified items. When all the re-inspections are qualified, only the unqualified products in the initial inspection shall be returned for repair. If there are still unqualified items after re-inspection, no matter how many, the batch of products will be regarded as unqualified and must be repaired and resubmitted for acceptance. 8 Marking and packaging
8.1 Marking
8.1.1 Manufacturer name and trademark.
8.1.2 Gas identification mark
a. Oxygen valve body or head should be marked in blue. b. Gas valve body or head should be marked in red. 8.1.3 Mixing method mark
Injection and suction mixing is indicated by 1.
Isobaric mixing is indicated by 2.
8.2 Packaging
Small packages should be beautiful and sturdy, and the product name, model and manufacturer name should be marked. Large packages should be sturdy, meet transportation requirements and relevant regulations, and the product name, model, quantity, gross weight, net weight, volume, year and month of manufacture and manufacturer name should be marked. The font should be correct and clear. Additional Notes:
This standard was proposed by the National Welding Standardization Technical Committee of the Ministry of Machinery and Electronics Industry. This standard was drafted by the Harbin Welding Research Institute of the Ministry of Machinery and Electronics Industry. The main drafters of this standard are: Lv Zhenjie, Meng Zhaoguang, and Liu Hongge. 544
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