JB/T 6445-1992 Fan impeller overspeed test JB/T6445-1992 Standard download and decompression password: www.bzxz.net

Machinery Industry Standard of the People's Republic of China
Ventictor Impeller Overspeed Test
1 Subject Content and Scope of Application
JB/T 6445—92
This standard specifies the fan impeller Overspeed test conditions, preparation before test, test procedures, evaluation of test results and test report. This standard is applicable to the overspeed test of centrifugal and axial flow fan impellers, as well as the overspeed test of fan rotors. 2 Reference standards
GB3177 Inspection of dimensions of smooth workpieces
ZBJ72042 Fan rotor balance
3 Test conditions
3.1 Overspeed test and measurement of impeller unless otherwise specified + should be carried out at normal temperature; when measuring dimensions before and after the test, the temperature difference of the impeller should not be greater than 10°C. If correction is needed, the value of 20°C should be used as the standard, and the measured temperature should be recorded. 3.2 Testing instruments and measuring tools should meet the following requirements: a. The accuracy of the speedometer is ±1%;
b. The accuracy of the vernier caliper should comply with the regulations of GB3177. 3.3 The instruments and measuring tools used for testing must be checked and calibrated before and after the test, and their performance and errors should comply with the relevant standards. 3.4 The test equipment should meet the rotation speed and load required for the impeller overspeed test. The operation must be stable and reliable, and equipped with a safety shield. The control and speed measuring device should be installed in a safe, reliable and easy-to-observe place. The foundation of the test equipment is easily located below the ground level, and the depth from the ground is determined according to the size of the impeller to ensure that the test equipment does not exceed the ground level. Safety guardrails should be set up around the test equipment at least 1050mm above the ground level. 3.5 It is recommended to conduct overspeed test in vacuum state, and it is also allowed to install a baffle at the impeller inlet. 4 Preparation before the test
4.1 The impeller must comply with the requirements of the drawings and process documents, and be balanced and calibrated according to the requirements of 2BJ72042. 4.2 Check the complete set of technical documents, instruments, measuring instruments and tools. 4.3 Check the integrity of the test equipment.
4.4 Check that the welds, rivets, discs, wheel covers, wheel hubs, etc. of the impeller should be free of cracks and looseness. 4.5 Carry out the following measurements in two mutually perpendicular radial directions of the impeller, make records, and mark the corresponding parts. 4.5.1 Centrifugal impeller:
The inlet inner diameter of the wheel cover;
a.
b. The outer edge diameter of the impeller;
“c. The diameter of the blade at the impeller outlet Verticality. 4.5.2 Axial flow impeller:
a．inch wheel diameter;
blade installation angle at impeller outer diameter
b.
People's Republic of China. The Ministry of Mechanical and Electronic Industry approved the implementation on 1993-01-01 on 1992-07-20
329
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5 Test steps
JB/T6445--92
5.1 Install the impeller on the main shaft of the test equipment, clamp it firmly and turn it by hand to confirm that it is flexible, and cover it with a safety guard Cover and move all personnel away to a safe and reliable area.
5.2 If a vacuum device is provided, the vacuum should reach the specified value. 5.3 Start the test equipment and observe the tachometer to ensure that the impeller rotates at no less than the maximum working speed of the impeller. Run at % speed, and the duration shall not be less than 2 minutes
5.4 Stop the machine and remove the impeller, conduct the following inspections, and make records; re-measure the corresponding dimensions of the parts marked before the test; Re-measure the verticality of the blades at the marked parts; b.
c.
d.
Re-measure the installation angle of the blades for the axial flow impeller: check the welds and discs of the impeller , wheel covers, wheel hubs, etc., and whether the rivets are loose or cracked. 6 Evaluation of test results
6.1 There must be no cracks in the welds, wheel discs, wheel covers, wheel hubs, etc.; the rivets must not be loose or cracked. 6.2 The dimensional deformation of the inlet diameter and impeller outer diameter of the centrifugal impeller cover or the axial flow impeller diameter shall not exceed the requirements in the table below
Impeller type
Centrifugal|| tt||Axial flow type
position
position
wheel cover inlet inner diameter
impeller outer rim diameter
impeller diameter
after test Dimensions
Dimensions before test
Note: Dimensional deformation 1
1 The verticality shall not exceed the provisions of the drawing. 6.4 The installation angle of the blade at the outer diameter of the axial flow impeller shall not exceed the provisions of the drawing. The dimensional deformation
≤0.5/1000
6.5 When any of the above does not apply. When the regulations are met, it is allowed to rework and redo the balance correction, and then do another (only one) overspeed test. The results should comply with the provisions of Articles 6.1 to 6.4. Otherwise, the product will be deemed unqualified if the number of loose rivets is less than 5%. When the machine is repaired, no overspeed test is allowed after repair
7 Test Report
After the overspeed test, the tester should fill in the "Impeller Overspeed Test Report" (see Appendix A) and keep it on file for at least 5 years. . 330
Company name
Test number
Fan model
Maximum operating speed
Serial number
1
Item| |tt||Welding
Riveting
Impeller outer rim diameter
mm
Wheel cover inlet inner diameter
Imm
5||tt ||8
Additional notes:
mesh
seam
nail
blade verticality, mm
axial flow impeller outer diameter, mm
Axial flow impeller blade installation angle
Impeller temperature, ℃
1
JB/T 6445--92
Appendix A||tt| |Impeller overspeed test report format
(reference part)
Impeller overspeed test report
Test time
Impeller number
r/minj||tt| |Test speed
Actual measurement before test
2—2
3—3
4-—4
This standard is proposed and approved by Shenyang Blower Research Institute Return to home. Actual measurement after test
Conclusion
r/min
hour
minute to
standard
ambient temperature
size and position
set deformation
standard value
no cracks
year
disk
month
minute|| tt||Comments
No looseness,
No cracks
Dimensional deformation
≤0.5/1000
(Pattern tolerance)
≤0.5/1000
(Pattern tolerance)
Temperature difference ≤10℃
Qualified
Unqualified
Tester
Responsible person| |tt||This standard was drafted jointly by Chongqing General Machinery Factory and Shenyang Blower Research Institute. The main drafters of this standard are Liu Guanghua and Wang Lan. (Signature)
(Signature)
its
C
determined
331
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