Condition maintenance

Equipment status maintenance (examples)

1. Significance

Equipment is an important material and technical basis for completing railway transportation production. Equipment maintenance is an important measure to ensure that the equipment is in good condition. For a long time, the maintenance of the railway system has followed the regular equipment repair system of the former Soviet Union, which is very blind. It is difficult to accurately grasp whether the equipment has faults, the location of the faults, and the extent of the faults. In addition, due to repeated disassembly of good parts, the mechanical performance is often not ideal, even lower than before maintenance, and there is no necessary advance maintenance, resulting in a huge waste of manpower and material resources. Equipment status maintenance is equipment maintenance that is carried out when the equipment is running or basically not disassembled, using different information generated by the equipment, using instruments to collect, process, and analyze signals, determine the location and cause of the failure, and predict the service life of the equipment. Way. Status detection avoids sudden failures of mechanical equipment, thereby avoiding forced shutdowns that affect production; status detection analysis provides a reliable basis for predicting the maintenance period of mechanical equipment, so that maintenance can be carried out only when necessary. At the same time, it is convenient to prepare maintenance parts and arrange maintenance plans in time, overcome unnecessary economic losses and decrease in equipment performance caused by regular maintenance, avoid blindness in maintenance, make maintenance simple and easy, and greatly shorten the maintenance period.

2. Analysis of the current situation of the enterprise

With the increasing maturity of condition detection theory research and the advancement of modern science and technology, the software and hardware conditions for equipment condition maintenance have been met.

At present, Yanzhou Locomotive Depot has 182 sets of mechanical power equipment, with an original value of fixed assets of 25 million yuan. Among them, there are 24 pieces of Class A equipment, 143 pieces of Class B equipment, and 15 pieces of Class C equipment. In the past, regular maintenance was carried out for Class A and B equipment, and post-event maintenance was carried out for Class C equipment. In order to save maintenance costs, ensure safe production, and improve equipment utilization, regular maintenance supplemented by condition maintenance is now implemented for Class A equipment, condition maintenance is performed for Class B equipment, and post-event repair is performed for Class C equipment. This avoids repeated repairs and excess repairs, reduces labor intensity, improves equipment utilization, and reduces maintenance costs.

3. Steps to carry out condition maintenance

1. Purchase instruments, assign dedicated personnel, and conduct business training

To carry out condition maintenance, the company first purchased mechanical condition detection equipment, thermometers, tachometers, and HG3518 waveform detectors. Dedicated personnel were assigned and a status inspection team was established. The personnel are sent to the manufacturer for training so that they can master the basic knowledge and professional technical knowledge of equipment condition inspection, and then go to units that are good at carrying out condition inspection for on-site learning.

2. Correctly select the measuring points of the equipment under test and number each measuring point

The selection of measuring points is critical, because the selected measuring points will affect the authenticity of the data. The selected measuring points are recorded on the drawings for future reference and verification. The principles for determining detection points are: (1) Sensitive points to machine vibration, key points closest to the core of the machine, and vulnerable points prone to deterioration. (2) Select rigid support points. Such as: machine base, bearing seat, etc. (3) For large machinery, measurements must be made at the front, rear, top, bottom, left, right, and middle parts of the machine. (4) Environmental factors should be considered when selecting measurement points. For example: large vibration sources, avoid high temperature, high humidity points and air outlets. (5) The selection of the number of measuring points should reflect the main operating status of the machine.

3. Establishing enterprise standards

Establishing enterprise standards is an important step in achieving equipment condition maintenance. Equipment status detection and fault diagnosis work are carried out around setting standards and comparing standards.

First of all, refer to the international standards ISO 2372 and ISO 3945, and establish enterprise standards based on the actual situation of the enterprise. The normal values, caution values ??and dangerous values ??of each measuring point of each piece of equipment were determined. The three values ??are divided into four areas, namely: good area, normal area, caution area and dangerous area.

The measured value in the good area indicates that the equipment is operating well; the normal area indicates that the equipment is operating normally; the measured value in the attention area indicates that there are some problems with the operation of the equipment, and monitoring and inspection must be strengthened; and the measured value in the dangerous area indicates that the equipment must be inspected and repaired.

By repeatedly testing each measuring point of a single device or multiple devices of the same type, usually more than 50 times, a large number of measured data values ??under normal conditions (such as: displacement, speed, acceleration, temperature etc.) to obtain an average value, and through collation and analysis, multiplier factors and correction coefficients are introduced to determine normal values, caution values, and dangerous values. Under normal circumstances, 1.1 times the average value is considered the normal value, 2.5 times the normal value is the caution value, and 5 times the normal value is the dangerous value. Establish corporate standards on a device-by-device basis.

4. Determination of the inspection cycle

Formulate the inspection cycle based on the equipment life curve (bathtub curve). The company stipulates that the testing period for newly installed and overhauled equipment is 7 days, the testing period for equipment in normal operation is 15 days, and the testing period for equipment with long service life and unstable condition is 7 days. During the detection process, once changes are found in the measurement data, the detection cycle will be shortened. When the measured data returns to normal, detection will be carried out according to the specified cycle.

5. Data collection and processing

According to the actual measurement points of the enterprise, the unified numbers are input into the computer data processing system, the equipment measurement point file ledger is established, the correct enterprise standards are entered, etc., and the status inspection system is initialized. Then use the HG3518 data collector to collect data from the equipment measurement points during the detection cycle. During the process of collecting data, attention should be paid to the correspondence between each measuring point and the measuring point in the selected equipment ledger, and the ambient temperature and equipment operating conditions should be recorded. Under normal circumstances, only the peak value of each equipment measuring point is measured. If the peak value is in the normal area, it can be detected and recorded according to the normal detection cycle. If the measured peak value is in the caution area or dangerous area, the detection period must be shortened, and HG3518 waveform collection is used. The instrument collects waveforms and provides data for further analysis.

When inputting the collected data into the computer software system, during the waveform or data transmission process, attention should be paid to the correspondence between the measurement points and the ledger. For equipment measurement points where the data exceeds the attention area, waveform spectrum analysis should be performed to determine Fault location and status. Then conduct quality analysis and remaining life prediction of the equipment, and determine the maintenance items and dates.

6. Quality information management

Quality information management is a detailed and large-scale work. First, the original status data of the equipment should be collected, and secondly, the equipment faults should be recorded, including the collection of previous equipment fault information and the record of current equipment faults. Do a good job in recording and excerpting "equipment failures".

The equipment maintenance team establishes equipment testing files for the tested equipment, including text files and computer files.

For faulty equipment, trend analysis and waveform analysis should be conducted, and a fault notification ticket should be issued to notify the relevant team to perform maintenance. The maintenance team should feedback the equipment maintenance order to the status inspection team and establish a dynamic file.

The process flow of equipment detection data collection and analysis is shown in Figure 1.

4. Effects

In 2002, through condition maintenance of all Class A and Class B equipment, *** fault notifications were issued for maintenance 120 times, and the actual maintenance cost 100,000 yuan. In the past, the number of scheduled maintenance was 465 times, and the maintenance cost was 350,000 yuan, saving maintenance cost of 250,000 yuan.

The maintenance downtime was reduced from the original 1860h to 520h, which greatly improved the equipment utilization rate.

Figure 1

5. Consolidation measures

In the future, Chongzhou Locomotive Depot plans to gradually expand the scope of equipment status maintenance, refine enterprise judgment standards, and increase electrical testing Instruments and modern testing equipment, improve the professional quality of condition testing personnel, strengthen business training, and add expert diagnosis systems.

Make the entire equipment in condition maintenance, gradually cancel regular repairs, save maintenance costs, reduce repeated repairs, and improve labor efficiency.