JB/T 50149-2000 Product reliability assessment method for small roller mill
Some standard content:
Machinery Industry Standard of the People's Republic of China
JB/T50149-2000
Small Roller Mill
Product Reliability Assessment Method
(Internal Use)
Published on 2000-08-18
National Machinery Industry Bureau
Implemented on 2000-12-01
JB/T50149-2000
This standard is specially formulated to implement the reliability assessment and certification of small roller mill products. Appendix A of this standard is the appendix of the standard.
This standard is proposed and managed by the National Agricultural Machinery Standardization Technical Committee. The responsible drafting unit of this standard: Shandong Agricultural Machinery Science Research Institute. The drafting units of this standard include: Henan Penguin Group Co., Ltd., China Agricultural Mechanization Science Research Institute, Shandong Flour Machinery Factory, Henan Zhongyuan Roller Co., Ltd., Henan Xiuwu Yongle Grain Machinery Group, Henan Luohe Roller Factory, Hebei Zanhuang Machinery Factory, Anhui Wuhe Machinery Factory, Henan Nanyang Guanghui Machinery Factory, Shandong Hushan Grain and Oil Machinery Co., Ltd. The main drafters of this standard include: Zhou Qingnong, Sun Zhongpei, Ma Nailan, Li Zhiqing, Li Yunliang. 1 Scope
Machinery Industry Standard of the People's Republic of China
Small Roller Mill
Product Reliability Assessment Method
(Internal Use)
JB/T50149—2000
This standard specifies the reliability assessment method, use test method and fault judgment rules of small roller mill products. This standard applies to the reliability assessment of small roller mill (hereinafter referred to as mill) products. 2 Referenced 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. JB/T5681-1991 Test method for small roller mill 3 Definition of terms
This standard adopts the following definitions.
3.1 Failure
Any phenomenon in which the mill cannot complete its specified function or the performance drops beyond the specified range is called a failure or failure. 3.2 Essential Failure
Failures caused by inherent defects of the mill are called essential failures, such as: the magnetic metal content of the processed flour exceeds the specified value due to unqualified roller material or improper roller drawing, the noise value exceeds the specified value due to improper motion parameter design or the machine processing quality does not meet the requirements or the assembly quality is poor, and the excessive deformation, breakage, excessive wear of the machine parts caused by hand strength, material, processing and assembly, bearing overheating, loose or failed fasteners, bearing oil leakage, screen leakage, etc. are all essential failures. 3.3 Subordinate Failure
Derived failures caused by essential failures are called subordinate failures. For example: if the mill breaks the screen and other parts are damaged due to damage to the moving parts of the screen body, the damage to the moving parts of the screen body is an essential failure, and the damage to other parts caused by this is a subordinate failure. 3.4 Misuse Failure
Failures caused by users not using and operating the mill according to the instructions are called misuse failures. For example, the failure of misuse may be caused by the hopper being empty and the two grinding rollers grinding in vain, resulting in premature wear of the grinding rollers, or the magnetic metal content in the flour exceeding the limit. 4 Reliability assessment method
4.1 Reliability assessment indicators
4.1.1 Mean time before first failure MTTFF Approved by the State Machinery Industry Bureau on August 18, 2000, and implemented on December 1, 2000
Where: MTTFF
JB/T50149-2000
-Mean time before first failure of grinding mill, h: Number of grinding mills investigated or tested:
Number of grinding mills investigated or tested that had their first failure (excluding minor failures) during use or testing; t
The accumulated working time when the first failure of the th grinding mill occurred, h; ()
The accumulated working time of the th grinding mill that did not have its first failure at the end of the user survey or reliability test, which is the timed truncation test time for the grinding mill undergoing reliability test, h. If the mill under evaluation and test does not have any failure within the specified time (except for minor failures), it is stipulated that MTTFF>) 4.1.2 Mean time between failures MTBF
Where: MTBF-
Mean time between failures of the mill, h;
Number of mills under investigation or test:
(2)
The cumulative working time of the mill under investigation, for the mill under reliability evaluation test, the specified timing cut-off time ter
, h;
The number of failures that occurred during the use or test of the mill under investigation or test (except for minor failures). If all the mills under test do not have any failure (except for minor failures) within the specified test period, it is stipulated that MTBF>.
4.1.3 Reliability R
MTBF+MTTR
Reliability, the proportion of time that the product can maintain its specified function during the reliability assessment period, %: Where: R
Mean time between failures, h;
Mean time to repair, h;
MTTR=-
The repair time required for the first failure, including the sum of the time for fault diagnosis, repair implementation and debugging, that is, the time from shutdown due to failure until diagnosis, repair completion, and restart of operation, h. 4.2 Assessment method
4.2.1 Data source
The data used for the reliability assessment of the grinding mill can come from the following three aspects. 4.2.1.1 Use test
Data obtained by conducting reliability tests in combination with production use in accordance with the provisions of the use test method of this standard. 4.2.1.2 User survey
Reliability data of the actual use of the grinding mill obtained by conducting a sampling survey among users. 4.2.1.3 Laboratory reliability test
JB/T50149-2000
Data obtained from the reliability test of the grinding mill conducted in a laboratory under controlled conditions according to a specific method. To conduct this test, the equivalent relationship between the test time and the actual user usage time must be known in advance. 4.2.2 Fault determination
All grinding mill faults are determined one by one according to the provisions of this standard for fault determination, and the nature and category of each fault are used as the basis for calculating relevant indicators.
5 Use test method
The use test method of this standard is mainly used for the reliability assessment use test of mass-produced grinding mills, and the reliability use test of trial-produced prototypes can also be implemented as a reference.
5.1 Test prototype
5.1.1 Number of test prototypes
2 complete grinding mills.
5.1.2 Sampling method
Supervised by the sampling personnel of the reliability assessment test unit, random sampling is conducted from qualified products produced in the factory in the past year. The sampling base is not less than 16 units, and the number of samples is 4 units.
5.1.3 Each test sample sent to the test site should have the following documents and spare parts: a) Mill sampling registration form;
b) Mill factory certificate;
c) Mill instruction manual:
d) Spare parts that should be brought according to the instruction manual or relevant documents of the reliability assessment test. 5.2 Test method
5.2.1 The use conditions of the mill should comply with the relevant provisions of the instruction manual. 5.2.2 After the mill is installed, run it idle for 15 minutes. 5.2.3 After the mill is run idle, grind it with bran for 15 minutes to clean the grinding roller, grinding chamber and screening equipment. 5.2.4 After the mill has completed the idling run-in and the cleaning of the ground bran, the mill use test shall begin. 5.2.4.1 The use test stipulates the processing of standard flour. 5.2.4.2 During the use test, the output of the grinding roller centimeter when processing standard flour should not be less than 5.0kg powder/(cm·h). 5.2.4.3 The reliability assessment time of the use test is 200h (the cumulative working time of each prototype). 5.2.4.4 During the use test, three performance tests shall be carried out in accordance with the provisions of JB/T5681 at the initial stage (during normal operation), middle stage (after 100h) and late stage (near the end of the test), and the test results shall be filled in Table 1. 5.2.4.5 Keep a record of the daily use test. Fill in the working conditions of each shift in Table 2. 5.2.5 All faults that occur during the test (including idling running-in, bran grinding and performance testing) should be recorded in detail, including the time, situation, cause analysis, repair measures, and repair work time, and the category of the fault should be determined according to the relevant provisions of this standard and recorded in Table 3.
5.2.6 During the test (including performance testing), general faults and serious faults that occur must be eliminated before continuing the test. 5.2.7 During the test, if there is any major damage caused by non-essential reasons, the spare prototype can be used to re-test. 5.2.8 After the test, fill in the comprehensive summary table of the mill reliability assessment test according to the requirements of Table 4, and fill in the reliability assessment test result summary table according to the requirements of Table 5.
5.3 Test report
JB/T50149-2000
After the test, sort out the test results and prepare a reliability test report based on the test data. The reliability test report should include the following contents:
a) Test responsible unit and participating units:
b) Test purpose, requirements, start date and location: c) Main technical specifications and parameters of the mill:
d) Test conditions:
e) Test results;
f) Test conclusion.
6 Fault judgment rules
The fault judgment rules of this standard are used to analyze and evaluate the faults that occur during the use and test of the mill. 6.1 Fault Classification
According to the degree of harm caused by the mill fault and the difficulty of eliminating the fault, the fault can be divided into four categories: fatal fault, serious fault, general fault and minor fault. Its categories, names, codes and descriptions are as follows: Category
Fatal failure
Serious failure
General failure
Minor failure
6.2 Judgment rules
Failures that endanger or cause personal injury or death, cause the scrapping of major components or cause major economic losses. Failures that seriously affect the normal use of the mill, or the specified important performance indicators drop beyond the specified range and must be shut down for repairs, and the repair cost is high. It cannot be eliminated within a short effective time and requires replacement of more important parts, or the body must be disassembled to replace parts. Failures that obviously affect the normal use of the mill and have medium repair costs. Failures that can be eliminated within a short effective time, that is, failures that require replacement or repair of external parts. Failures that slightly affect the use of the mill and will not cause temporary work interruption. Failures with low repair costs, that is, failures that can be eliminated with random tools during daily maintenance. 6.2.1 Reliability assessment should count the essential failures of the mill. If the essential failure and subordinate failures occur at the same time, they should be recorded once as the failure with the most serious consequences. Misuse faults are not counted in the number of faults, but should be recorded in the fault registration form truthfully. 6.2.2 When determining the type of mill fault, the type of fault should be determined based on the final consequences, and can only be determined as one of the four types of faults.
6.2.3 Maintenance and scheduled replacement of random spare parts in accordance with the instructions for use are not considered fault handling, but records should be kept. 6.2.4 When counting the number of faults, such as oil leakage, powder leakage, bran leakage, and loose fasteners, one sealing joint surface is counted as one time. 6.2.5 After troubleshooting, the same fault that recurs repeatedly should be counted separately. 6.2.6 When determining the type of fault, refer to the fault examples in Appendix A (Appendix to the standard) for judgment. Due to the different structures of various mills, the consequences and difficulty of troubleshooting caused by the same fault will vary greatly. Therefore, when actually judging the fault, it should be judged according to the definition of each type of fault and the specific situation with reference to the fault examples. 4
Product model:
Prototype number:
Test location:
Test items
Power consumption per ton of flour
kw·h/t
Magnetic metal objects in flour
Grinding roller output per centimeter per hour
kg flour/(cm·h)
Noise dB
Maximum bearing temperature rise
Flour processing accuracy
Gluten quality (wet)
Flour ash content (dry)
Flour coarseness
Flour smell and taste
Maximum temperature of milled material
Test participants:
JB/T501 49-2000
Table 1 Summary of performance test results of grinding mill
Manufacturing unit:
Date of manufacture:
Test start and end date:
Pre-test period
Prototype No. 1
Prototype No. 2
Mid-test period
Prototype No. 1
Prototype No. 2
Verification:
Post-test period
Prototype No. 1
Prototype No. 2
Product model:
Prototype number:
Test location:
Grinding mill operator:www.bzxz.net
Reliability assessor:
Product model:
Prototype number:
Test location:
Fault occurrence
Date of occurrence
Grinding mill operator:
Reliability assessor:
JB/T50149-2000
Table 2 Grinding mill reliability assessment test shift record sheetManufacturer:
Factory date:
Test start date:
Working hours
h, min
Fault name
Processing volume
Power consumption
Record:
Table 3 Reliability assessment test fault registration sheet
Manufacturer:||tt ||Factory date:
Test start date:
Damaged parts
Fault cause
Fault troubleshooter:
Grinding roller cm-hour
kg powder/
(cm·h)
kw·h/t
Fault troubleshooting
Cost of troubleshooting
(Yuan)
Product model:
Prototype number
Accumulative idling time
Accumulative working time h
Accumulative processing volume
Accumulative maintenance time
Accumulative repair time h
Accumulative power consumption kW·h
Average power consumption per ton of powder Consumption
kw·h/t
Average grinding roller output per centimeter hour
kg/(cm·h)
Test location
Test participants
Assessor:
Product model:
Test location:
Fault category
Fatal fault
Serious fault
General fault
Minor fault
Fault accumulation
Reliability index:
MTTFF=
JB/T50149-2000
Table 4 Comprehensive summary of reliability assessment test of grinding millManufacturer:
Prototype No. 1
Table 5 Summary of reliability assessment test results
Manufacturing unit:
Test start and end date:
Prototype No. 1
Prototype No. 2
Prototype No. 2
General parts
Casing, frame
Parts inside the body
Important parts outside the body
Important fasteners outside the body
Oil leakage, powder leakage, bran leakage
Protective cover
General parts outside the body
Important fasteners outside the body
Oil leakage, powder leakage, bran leakage
Surface paint film
Electroplating layer
General fasteners on the outside of the machine body
Oil leakage, powder leakage, bran leakage
Surface paint film
Performance part
Power consumption per ton of powder
Magnetic metal objects
Bearing temperature rise
Power consumption per ton of powder
Grinding roller output in centimeters per hour
Magnetic metal objects
Bearing temperature rise
Power consumption per ton of powder
JB/T50149-2000
Appendix A
(Appendix to the standard)
Examples of powder machine failures
Failure mode
Breakage, disengagement
Damage or failure
Damage or failure
Multiple damage or shedding
Serious leakage
Damage or failure
Individual damage or shedding
General leakage
Large area shedding
Multiple point peeling and rusting
Damage or shedding
Minor leakage
Local shedding
Failure mode
Exceed the specified value by more than 15%
Exceed 0.005g/kg
Exceed 50℃
Exceed the specified value by 3~5dB
Exceed the specified value by within 10%~15%
Less than 5.0kg/（cmh）
Exceed 0.003g/kg
Exceeds 25℃, below 50℃
Exceeds the specified value by 1~3dB
Exceeds the specified value by less than 10%
Situation description
Causes connection failure
Repair requires replacement of parts
Does not cause connection failure
Repair requires replacement of parts
Does not cause connection failure
Repair can be made without replacing parts
Situation description
Fault category
Fault category
A3 grinding head part
Gap adjustment mechanism
Pulley, bearing seat, gear and other parts|| tt||Filling block,:
Flow regulating mechanism
Grinding distance regulating mechanism
Feeding mechanism
Gear box
Flow regulating mechanism
Grinding distance regulating mechanism
A4 screen body
Bearing seat, pulley, etc.
Brush, beating plate
Screen silk fastening device
JB/T50149-2000
Failure mode
Loosening of grinding roller shaft
Bearing failure
Failure, unable to adjust
More than 2 broken wires
Failure, unable to adjust
Closing Locking failure
Material leakage from both ends of the grinding wheel
Ineffective adjustment
Ineffective adjustment
Failure mode
Bran leakage, bran in powder
Powder leakage, bran leakage
Situation description
Grinding roller must be replaced
The journal must be repaired or the bearing must be replaced
Repair can only be carried out by replacing parts
Repair can be carried out by adjustment
Situation description
Failure category
Failure category
People's Republic of China
Mechanical industry standard
Small roller mill
Product reliability assessment method||tt| |(For internal use)
JB/T50149-2000
Published by the China Academy of Mechanical Science
Printed by the China Academy of Mechanical Science
(No. 2, Shouti South Road, Beijing
Postal Code 100044)
Sheet size 3/4, word count 20,000
Format 880X1230
First edition in November 2000
First printing in November 2000
Print run 1-500
Price RMB 15.00
2000-164
Mechanical Industry Standards Service Network: 00
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