I. Introduction
To modernize equipment management, enterprises should actively promote advanced equipment management methods and take equipment maintenance techniques based on equipment condition monitoring.
Equipment condition monitoring and fault diagnosis techniques are prerequisites for preventive maintenance of equipment. Especially in our water supply industry, our work continuity and safety and reliability requirements are high. With the promotion of condition monitoring, we can gradually grasp the working status of major water supply equipment such as pumps and motors, find out the deterioration trend of some wearing parts, And the repair cycle more in line with the actual needs of the equipment, saving maintenance costs, eliminate downtime accidents and improve economic efficiency of enterprises.
Second, the pump overhaul management status quo
At present, there are generally two types of determining the major repair cycle of a pump group in a water supply enterprise: a cumulative or regular maintenance when running the platform. Most of the water division is based on the pump station run time, that is, when the pump total run to 4000 to 5000 hours, as a major repair cycle, began to pump overhaul. However, when some water companies do not evaluate the operation platform, only the pump set is repaired in annuals, that is, one year is a major repair cycle. Before annual peak water supply, all pump sets are routinely serviced. Whether it is based on the stage or the annual maintenance of large repair cycle methods are too old, but also belong to the experience of management planning maintenance, lack of scientific, such maintenance model that has been too suspect, there is the possibility of accident downtime. To get out of the traditional maintenance mode, the planned periodic maintenance is gradually transitioned to the status of predictive maintenance, to overcome the unnecessary economic losses caused by regular maintenance and the decline of equipment performance, so that the major repairs and management of water supply enterprises from experience management Gradually move towards scientific management, but also need to do a lot of hard work, of which rely on advanced scientific instruments as a means of detection is effective, essential.
Third, the current use of several vibration meter
1, France produced 4576DA multi-function portable vibrometer, the measurement parameters of acceleration, speed, displacement, rolling defects, mainly used for random testing equipment running status.
2. Beijing HG-3518 data acquisition fault diagnosis system produced by Beijing Airline Co., Ltd. The measurement parameters are acceleration, speed, displacement, temperature and rotational speed. The main equipment is at the first-class equipment management department and is equipped with application analysis software.
3, Beijing Beijing Airlines company produced a HG-2506 Pocket Vibration Meter for low frequency (5Hz) to measure acceleration, speed, displacement. Mainly to the water plant equipment managers and operating workers configuration.
Fourth, the use of vibration meter
In recent years, the national water supply enterprises have carried out their work in different aspects in the equipment condition monitoring. At the beginning of the nineties, water division used pulse vibrometer, oil analyzer, multi-channel timer and other instruments. Due to the lack of standardized management and technical guidance, the instrument is sent to the workshop maintenance workers or operators in view of the different technical levels, the application has a lot of randomness, combined with the instrument itself is not stable, the operation is not easy In all aspects, this work has not been carried on well. However, after a period of work carried out, it is necessary to deeply understand the application status monitoring technology of water supply enterprises, especially waterworks. Tianjin, Fuzhou, Lanzhou, Guangzhou, Ningbo and other water divisions, have carried out using vibrometer instrumentation pump overhaul work. Some water divisions have achieved good results, gained a lot of valuable experience, while others have just started or are about to do this work.
Take Tianjin Company as an example. In 1996, Tianjin Company utilized the opportunity of introducing new capital by expanding Xinkaihe waterworks. At the same time of introducing water equipment, it introduced a batch of equipment for condition monitoring. This time, we accepted the previous practice of Building Blocks. From the selection of equipment and staffing to the management mode, we have put our emphasis on practicality and effectiveness. The equipment department of the company is responsible for promoting the monitoring work. According to the characteristics of the equipment and the specific conditions of the equipment to be seized, the necessary reports are designed and the tests are carried out in a combination of specific groups. The Company selects the key plants and key equipment for regular (monthly) In order to increase the monitoring density and monitoring surface, the instrument is distributed to the waterworks at the grassroots level under the premise of the permission of the instrument possession. After the plant manager of the training plant is trained, the instrument can be applied to the measurement. The grassroots water works fill the measured data into the field test record sheet (Table 1) and report it regularly to the equipment department of the company. The inspectors of the equipment department of the company draw the change curves according to the test results of the upper and lower levels (Table 2) , Analysis analysis software can also be used to make analysis curves so as to keep abreast of the running status of the equipment and guide the waterworks to timely replace the lubricating oil and wearing parts until the disassembly and overhaul so as to keep the equipment running in a good state.
in conclusion:
Xinkaihe water plant to pump a pump 7 # pump, model 32SA a 10, the motor capacity of 100 kilowatts. In December 1997 to 5875 hours of operation, according to past practice should be overhauled, but the application of vibrometer test results normal (speed value of up to 1.46mm / s, the highest acceleration value of 3.54m /, the highest displacement 13μm) can continue to use. Therefore, the company equipment management and plant consultation on the basis of this pump to strengthen the inspection tour to extend the overhaul cycle, when the pump operation 6700 hours, found at the bearing pad temperature is too high (1 # bearing pad side of the 56 ~ 63 ℃ ), But the measured value is still normal. Through the analysis is too much impurities in the oil, the proposed water change oil, oil change after temperature measurement, the temperature is normal (47 ~ 50 ℃), and continue to run until January 4, 1999; pump a total of 9536 hours of operation, Taking into account the pump running more million hours, but also before the peak water supply, so the pump for normal overhaul. Disintegration of the bearings did not find the problem.
Mustard Park pump 6 # pump room, model 28SA ~ 10A, the motor capacity of 630 kilowatts. After a major overhaul, the acceptance test with the instrument itself and found that the measured value is not normal, the equipment managers do not sign acceptance, repair workers recommended maintenance again, to avoid the sick pump operation. Through the use of vibrometer for a period of time, it really tasted the sweetness of using a vibrometer to guide the overhaul of the pump, and was also approved by waterworks leaders and maintenance workers. From their cooperation with the company, they detected their active application of the equipment to detect At the same time through the testing work carried out to improve the technical level of equipment management and maintenance workers.
Fifth, the measurement method and determine the basis
1, measuring point selection: the use of vibrometer, the main pump group of bearing parts and the axial end of a total of 14 measuring points for testing, together with the corresponding field test record form (Table 1), each measuring point must be a A correspondence.
2, the measurement period: depending on the pump operation may be. Generally just after the pump overhaul or close to overhaul should be two weeks once; normal operation once a month; in case of the measured value and the last time there is a significant change in the value of the test density should be strengthened to prevent accidents The result of downtime.
3, the measured value to determine the basis: with reference to international standards ISO2372
A: Good B: Better C: Allow D: Not allowed
The first category: small machinery (such as 15kW motor below)
The second category: medium-sized machinery (such as 15-75kW motor and the following 300kW machinery)
The third category: large institutions (installed on a rigid basis)
The fourth category: large institutions (installed on a more flexible basis)
Speed: 600-1200r / min, vibration measurement range: 10-1000Hz
Provisional in combination with the situation of water supply enterprises: When the pump is in normal operation, the detection speed value is in the range of 4.5 ~ 11.2mm / s (75kW and above) for monitoring and control, and over 7.1mm / s should be considered for overhauling. In addition to taking into account the capacity of the unit, this value is also taken into consideration for the low speed of the pump set used by the water supply enterprises and the high continuity of work and the high safety and reliability requirements.
Six, summary
Through the development of equipment testing, summarize the vibration meter in the water supply pump pump overhaul management applications, we get two inspiration:
1, water supply enterprises vibrometer state inspection of the pump group, although not as a pump overhaul cycle to determine the only basis, but as a reference condition is indeed very necessary. As the pump speed is low, low frequency, therefore, the harm caused by vibration is not the only. For example, some pump vibrometer detection is no problem, but impeller cavitation serious, also need to do big repair. Therefore, to determine the pump overhaul period should be measured from the vibrometer results, the cumulative running time of the pump and pump efficiency and other aspects to consider.
2, the application of vibrometer detection, as a major repair after the pump means of acceptance is also very necessary. It should be pointed out here is that due to the different levels of new and old pump, so the acceptance of the test values should not do a unified regulation should be accepted pump test before the overhaul of the test value, the value of the repair value after the test value Should not be unified provisions should be based on the pump unit is overhauled detection value, the repair value should be lower than the pre-repair value, and then run through the short-term operation after the situation should be better. In addition, the application of vibrometer can also be found in the pump group installation problems (including poor, anchor bolts loose long-term operation, etc.), as well as pump cavitation.
It is worth to explain one point: vibrometer and other testing instruments used in conjunction with more conducive to the pump running status analysis. Such as vibrometer and oil analyzer, motor fault detector, instrument and other instruments used in conjunction, will be able to more accurately determine the pump operation. In view of other testing equipment is not the focus of this article, it will not elaborate here.
Vibration meter in water supply enterprise overhaul management process has achieved initial success. Through this work, extending the continuous trouble-free operation of equipment, extending the maintenance cycle of equipment and reducing the number of overhaul, has brought considerable economic benefits to the enterprise. However, this has only just begun and needs to be further improved, enhanced and widely promoted, and the work is gradually institutionalized. We will continue this work to make the water supply equipment management more scientific and economical, and strive to bring it to a new level.
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