This standard specifies the method for evaluating the cleanliness of hydraulic components by the weight of residual contaminants inside hydraulic components and the cleanliness index determined by the allowable residual amount of contaminants inside hydraulic components. JB/T 7858-1995 Hydraulic component cleanliness evaluation method and hydraulic component cleanliness index JB/T7858-1995 standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T7858-95
Evaluation Method of Hydraulic Component Cleanliness
And Hydraulic Component Cleanliness Index
Published on December 1, 1995
Ministry of Machinery Industry of the People's Republic of Chinawww.bzxz.net
Implementation on July 1, 1996
Method of Hydraulic Component Cleanliness Evaluation
And Hydraulic Component Cleanliness Index
1 Subject Content and Scope of Application
JB/T7858-95
This standard specifies the method of evaluating the cleanliness of hydraulic components by the weight of residual contaminants inside hydraulic components and the cleanliness index determined by the allowable residual amount of contaminants inside hydraulic components. This standard applies to all kinds of hydraulic components and accessories with mineral oil as the working medium. 2 Definition
2.1 Inner cavity wet volume; the volume of the inner cavity in contact with the oil. 2.2 Inner cavity wet area: the inner cavity area in contact with the oil. 3 Equipment and instruments
One set of membrane filters.
3.2 Several mixed cellulose ester microporous filter membranes, diameter 60mm, pore size 0.45μm, 0.8μm. 3.3 One vacuum ticket.
3.4 ​​One balance with an accuracy of 0.5mg.
3.5 One non-air-cooled drying oven with a temperature of 80℃. 3.6 Other supplies (suction bottle, flat mouth forge, measuring cup, culture dish, small box, manual oil gun, syringe, white cloth, sampling bottle, etc.), environment and conditions
4.1 The cleanliness of the testing studio should reach Class 100000 (GBS73 <Cleanroom Design Specifications>), and the operator should wear special diving work clothes. 4.2 The tested component should be a component that has completed all processing and testing procedures. The cleaning container should be a pre-cleaned sampling bottle and other required containers. Its cleanliness shall not exceed 4.3 of the cleanliness of the tested component.
4.4 The cleaning liquid should be pre-filtered petroleum aldehyde (boiling range 60~90℃) or 120# industrial gasoline and other solvents. Its cleanliness shall not exceed 10% of the cleanliness of the tested component.
Note: It is recommended to filter with a microporous membrane with a pore size of 0.45μm. 5. Testing procedures
5.1 Measure the scene and record the magnetism. Demagnetize to below 12Gs when necessary. 5.2 Clean the outer surface of the tested component.
5.3 Determine the wet volume of the inner cavity of the tested component. 5.4 Disassemble the tested component (do not disassemble the process screw plugs and interference fit parts). 5.5 Remove the seals of each joint surface (except the hydraulic cylinder piston seal) and wipe the sealing surface with a white silk cloth. 5.6 Place all disassembled inner cavity parts into a clean container. Approved by the Ministry of Machinery Industry on December 1, 1995
Implemented on July 1, 1996
JB/T 785895
5.7 Spray the parts in contact with the working medium with a cleaning liquid. For parts that are partially in contact with the working medium, only clean the contact part of the parts. Parts that are not in contact with the working medium (such as the flange of the pump, the handle of the reading, the earrings of the cylinder, etc.) are not cleaned. The amount of cleaning liquid used is 2 to 5 times the wet volume of the inner cavity of the measured component.
5.8 Collect the flushing liquid in 5.7 into a container that meets the cleanliness requirements and mark the container number (such as sample No. 1). 5.9 Repeat procedures 5.6 to 5.8 twice, for sample No. 2 and sample No. 3 in turn. 5.10 Perform gravimetric analysis on sample No. 1, sample No. 2, and sample No. 3 according to the following single-membrane or double-membrane gravimetric analysis procedure. Note: Single-membrane and double-membrane gravimetric analysis methods are two optional gravimetric analysis methods. When the filter membrane can be fully rinsed by centrifuge, single-membrane analysis can be selected.
5.11 Single-membrane gravimetric analysis procedure
5.11.1 Take an appropriate amount of spare filter membrane (0.8μm) and place it in the culture medium, half-close the cover and put it in a drying oven, keep it at 80°C for 30 minutes, take it out and cover it to cool for 30 minutes
5.11.2 Take out a piece of dried filter membrane from the culture medium and weigh its original weight Gs. 5.11.3 Fix the filter membrane on the filter device, stir the sample to be tested thoroughly, and then put it into the filter device. Then flush the sample container with 50mL of clean washing liquid and put it into the filter device. Cover the funnel cover and filter. When about 2mL of residual liquid is left after filtration, remove the funnel cover and rinse the side wall of the funnel with clean washing liquid. Put on the funnel cover and continue filtering until the filter membrane is dry. 5.11.4 Use a syringe to absorb the clean washing liquid and inject it along the funnel wall to clean until there is no oil on the filter membrane. 5.11.5 Stop filtering. Carefully remove the filter membrane, place it in a culture dish, half-open the cover and place it in a drying oven, keep it at 80°C for 30 minutes, close the cover and take it out to cool for 30 minutes, then weigh it. Ga
5.11.6 The weight of the pollutant in the sample under test is G = Ga-Ga.5.12 Double filter membrane weight analysis procedure
5.12.1 Take an appropriate amount of spare filter membrane (0.8μm) and place it in a culture dish, half-open the cover and place it in a drying oven, keep it at 80°C for 30 minutes, take it out and close the cover to cool for 30 minutes.
5.12.2 Take out two dried filter membranes E and T from the culture dish and weigh their original weights E and Ta. 5.12.3 Fix the filter membrane on the filter device, with the filter membrane E on the top and T on the bottom. After fully stirring the sample to be tested, pour it into the filter device, rinse the sample container with 50mL of clean washing liquid and put it into the filter device. Cover the funnel cover and filter. When about 2mL of residual liquid is filtered, remove the funnel cover and rinse the side wall of the funnel with clean washing liquid. Cover the funnel cover and continue filtering until the filter membrane is dry. 5.12.4 Remove the full funnel cover, use a syringe to absorb the clean washing liquid, and inject and clean the funnel wall until there is no oil on the filter membrane. 5.12.5 Stop filtering. Carefully remove the filter membrane, put it into the culture medium, put it into the drying oven with the half-open cover, keep it at 80℃ for 30 minutes, close the cover, take it out and cool it for 30 minutes, and weigh its weight E and Ts. 5.12.6 The weight of impurities in the sample to be tested G = (E-E)(TT.). 5.12.7 If the value of (T.-T) is greater than 0.5 mg, it means that the filter membrane is not rinsed sufficiently, and 5.12.1 to 5.12.7 should be repeated. 6 Cleanliness test data processing and report format 6.1 Record the weight of pollutants G, GG of sample No. 1, sample No. 2, and sample No. 3 respectively, and calculate their total weight G=G+G+G. If G≤0.1G, the test result is considered valid. Otherwise, repeat 5.6 to 5.8, and obtain sample No. 4, sample No. 5* in turn, until the pollutant weight of the nth sample G,≤0.1G, and its total weight G=G,+G,+G,+G,+G,++**+G. 6.2 Record the test results. The total weight G of residual pollutants in the tested component is the sum of the weights of pollutants in all samples, that is, G=G,+G+G,++G.
6.3 Fill in the hydraulic component cleanliness test report. The format is specified in Table 1. 2
Inspected unit
Inspected product
Dense film pore size
Inspection time
Cleanliness index
Acceptance criteria
JB/T785895
Table 1 Hydraulic component cleanliness inspection report
Sample test location
Avoidance induction intensity
Inspector
Total weight of residual rat pollutants
According to the cleanliness index of main hydraulic components and accessories in Table 2 Regulations, acceptance of inspected components and accessories, Table 2 Cleanliness indicators of main hydraulic components and accessories
Product name
Gear pump and
Vane pump
Auxiliary column cold
Pump, motor
Low-build high-torque motor
Pressure control type
Throttle valve
Nominal displacement
Nominal displacement
Nominal diameter
Nominal diameter
10
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