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Machinery Industry Standard of the People's Republic of China
JB/T6896-1993
Surface cleanliness of air separation equipment
Published on July 13, 1993
Ministry of Machinery Industry of the People's Republic of China
Implementation on July 1, 1994
Machinery Industry Standard of the People's Republic of China
Surface cleanliness of air separation equipment
1 Subject content and scope of application
This standard specifies the surface cleanliness, inspection methods and assessment rules of air separation equipment JB/T 68961993
This standard applies to the cleanliness of the surfaces of parts and components in contact with oxygen in air separation equipment and the surfaces of parts and components that may be brought into contact with oxygen by dirt during equipment operation.
Surface cleanliness of air separation equipment
2.1 Solid matter
Solid matter includes: organic matter such as organic rust inhibitor, essence, paper, paint, etc.: welding slag and spatter, metal chips, welding wire and similar metals: sand and similar granular matter, as well as other substances that may dissolve under working conditions. 2.2 Cleaning fluid and water.
2.3 Rust scars.
2.4 Oil and grease.
3 Inspection methods and assessment rules
The inspection of cleanliness includes inspection of solid matter, cleaning fluid and water, rust scars and inspection of oil and grease residues. 3.1 Inspection of solid matter, cleaning fluid and water, rust scars 3.1.1 Visual inspection method
In bright light, directly use your eyes to inspect the inspection objects specified in Articles 2.1 to 2.4, and pay special attention to those parts that are not easy to clean.
3.1.2 Evaluation rules
The maximum diameter (or diagonal) of the solid particles remaining on the inspected surface shall not exceed 0.5mm, and the total number of solid particles with a diameter (or diagonal) between 0.25 and 0.5mm shall not exceed 100 particles/m; there shall be no obvious accumulation of fibers and dust, and the length of individual residual fibers shall not exceed 2mm; there shall be no cleaning fluid and water, the surface shall be dry, and there shall be no rust (rusty parts shall be derusted and inspected again).
3.2 Inspection of oil and grease residues
3.2.1 Gravimetric method
3.2.1.1 Principle
The method of cleaning the surface to be tested with carbon tetrachloride and heating it to volatilize the carbon tetrachloride in the cleaning fluid to obtain the residual oil content. 3.2.1.2 Apparatus and materials
300mL beaker:
b. Water bath:
Dryer:
Approved by the Ministry of Machinery Industry on July 13, 1993
Implemented on July 1, 1994
d Carbon tetrachloride (analytical grade);
e. Medium-speed qualitative filter paper:
f. Gauze:
g. Constant temperature box:
h. Balance.
3.2.1.3 Determination steps
JB/T6896-1993
The cleaning liquid used for inspection is carbon tetrachloride. If the final cleaning liquid of parts and components is not carbon tetrachloride, the inspection should be carried out after the final cleaning liquid is completely volatilized.
Step 1: Test carbon tetrachloride. Take 300mL of carbon tetrachloride with the same residual oil volume as this test, filter it with medium-speed qualitative filter paper washed with carbon tetrachloride, and pour it into a weighed beaker. Place the beaker in a water bath at 85±5℃ to volatilize the carbon tetrachloride (this operation is carried out in a good fume hood). After it is almost dry, place it in a constant temperature box at 50±5℃ to dry for 30 minutes, then put it in a dryer to cool for 30 minutes and weigh it. Calculate the weight difference m before and after the beaker. Step 2: Test the residual oil volume. Use carbon tetrachloride with a quantitative amount B to clean the residual oil on the surface to be tested. The cleaning area should be greater than 1m2, and if it is less than 1m2, it should be completely cleaned. Take 300mL of carbon tetrachloride containing oil after cleaning, filter it with medium-speed qualitative filter paper, collect the filtrate in a weighed beaker (300mL), place the beaker in a water bath at 85±5℃ to volatilize the carbon tetrachloride, and after it is almost dry, place it in a constant temperature box at 50±5℃ to dry for 30min, then put it in a dryer to cool for 30min and weigh it, and calculate the weight difference mi before and after the beaker. The grease residue on the measured surface is calculated according to formula (1): P=m-mo
Where: P
The grease residue on the measured surface, mg/m2:
Oil content of carbon tetrachloride containing oil after cleaning, mg: Oil content of carbon tetrachloride reagent, mg;
Cleaning area, m
Calculate according to formula (2):
Where: B-check the amount of carbon tetrachloride used in the cleaning solution, mL. B
For the parts that are inconvenient to clean, you can use tweezers to hold clean gauze without oil and soak carbon tetrachloride to wipe the residual oil on the surface to be tested. The wiped area is the same as the cleaned area. The total amount of carbon tetrachloride containing oil after wiping should not exceed 300mL. After filtering with medium-speed qualitative filter paper, pour it into a weighed beaker with a volume of 300mL, put it in a water bath pot at 85±5℃ to volatilize the carbon tetrachloride. After it is almost dry, place it in a dryer at 50±5℃ to dry for 30min, and then put it in the dryer to cool for 30min and weigh it. Calculate the weight difference m2 before and after the beaker. Then, according to the method of testing carbon tetrachloride in 3.2.1.3, take carbon tetrachloride of the same specifications and quantity (the quantity squeezed out after wiping) as this wiping inspection, and follow the same steps to calculate the weight difference m3 before and after the beaker. The residual amount of grease on the tested surface is calculated according to formula (3): P_mz -m3
Where: P—residual amount of grease on the tested surface, mg/m2; Oil content of carbon tetrachloride after wiping, mg: m2
JB/T 6896-1993
m3—Oil content of carbon tetrachloride with the same amount of wiping, mg: A—Wipe inspection area, m2.
Note: ①If the test is limited by equipment and other conditions, it is allowed to evaporate 300mL of carbon tetrachloride in a fume hood first, concentrate it to less than 100mL, and then test it according to this method.
②After cleaning, check whether the cleaned surface is rusty. If rusty, remove the rust and check it again after cleaning. 3.2.2 Oil concentration determination method
3.2.2.1 Principle
The tested surface is cleaned with carbon tetrachloride, and the residual oil content of the cleaning liquid is checked by an oil concentration meter. 3.2.2.2 Apparatus and materials
a. Oil concentration tester;
b. Medium-speed qualitative filter paper:
c. Beaker;
d. Carbon tetrachloride.
Wash the surface to be tested with carbon tetrachloride of quantitative B. For areas that are inconvenient to clean, use tweezers to hold clean, oil-free gauze soaked in carbon tetrachloride and wipe the surface to be tested, squeeze out the carbon tetrachloride B after wiping, take a portion of the carbon tetrachloride containing oil after cleaning or wiping, filter it with medium-speed qualitative filter paper, and then inject it into the oil concentration meter according to regulations to measure the oil concentration of the oil-containing carbon tetrachloride. The residual oil on the tested surface is calculated according to formula (4): P=M×_B
0.85=85×10~MB
The residual oil on the tested surface, mg/m2:
Where: P
M—reading of the oil concentration meter, Ppm; A
(4)
B—the amount of carbon tetrachloride used in the cleaning solution, mL (for wiping inspection, it should be the total amount of oil-containing carbon tetrachloride squeezed out after wiping): A—the cleaning or wiping inspection area, m2: 0.85—the average density of oil, mg/mL.
3.2.3 Other inspection methods
3.2.3.1 Irradiate the tested surface with ultraviolet light of wavelength 320~380nm. There shall be no grease fluorescence. However, this method cannot be used to inspect residual animal oil and vegetable oil.
3.2.3.2 Blow the tested surface with oil-free steam, take the condensate, put in pure camphor grains with a diameter of less than 1mm, and the camphor grains are qualified if they rotate continuously. bzxz.net
3.2.3.3 For the parts that are difficult to inspect with the above inspection methods, it is allowed to wipe the tested surface with white, clean, dry filter paper or silk cloth. There should be no oil marks on the paper or silk cloth when observed with the eyes. 3.2.4 Assessment rules
The residual amount of grease on the surfaces of parts and components that come into contact with oxygen, and the surfaces of parts and components that may be brought into contact with oxygen by residual oil during operation, shall not exceed 125mg/m2.
3.2.5 Inspection rules
3.2.5.1 Parts and components (and parts) that must be inspected quantitatively according to the design shall be inspected quantitatively according to the provisions of 3.2.1 or 3.2.2.
JB/T6896-1993
3.2.5.2 Other parts and components (and parts) may be inspected according to 3.2.3. In case of dispute, 3.2.1.
Processing of qualified parts and components
After the qualified parts and components are inspected, wipe off the cleaning fluid, blow dry and pack immediately. Additional remarks:
This standard is proposed and managed by Hangzhou Oxygen Concentrator Research Institute of the Ministry of Machinery and Electronics Industry. This standard is drafted by Hangzhou Oxygen Concentrator Research Institute. The main drafter of this standard is Zhang Hua.
People's Republic of China
Mechanical Industry Standard
Surface Cleanliness of Air Separation Equipment
JB/T68961993
Published and issued by the China Academy of Mechanical Science
Printed by the China Academy of Mechanical Science
(No. 2 Shouti South Road, Beijing
Postal Code 100044)
Format 880×1230
Sheet 1/2
Word Count 8,000
First Printing in July 1994
First Edition in July 1993
Print Quantity 1-500
Price 1.50 Yuan
Mechanical Industry Standard Service Network: http://www.JB.ac.cn661_9689/F
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