Talk about equipment inspection

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First of all, I would like to express my sincere gratitude to the Haichuan Chemicals platform. It was my first time posting on this platform – a post titled 【Unmanned】Quickly setting up network monitoring for air compressors in just 10 minutes – and I received many replies from users. Below, I will provide some information regarding routine inspections: What should be taken into account when conducting such inspections? The so-called inspection system is a equipment management method that involves checking specified parts of the equipment at regular intervals and according to certain standards, in order to detect potential faults early and carry out repairs or adjustments promptly, thus ensuring that the equipment maintains its designated functions. It is worth noting that the equipment inspection system is not merely a method of inspection, but also a system and management approach. Before understanding what routine inspections are, let’s first classify the equipment and conduct a preliminary inspection of each type of equipment one by one. Power equipment (including electric motors, internal combustion engines, steam engines, and combined power units used in areas without a power supply) is not used on its own; it usually serves as a driving element connected to the non-driving end of another device. The component that facilitates this connection is called a coupling, and mechanisms such as chains, belts, rigid links, or diaphragms are used to supply power to the equipment, enabling it to function and operate in production processes. Almost all rotating equipment is plagued by two core problems: high temperature and excessive vibration; therefore, we need to be aware of the impact these two factors have on the equipment. The impact of rising temperatures on power equipment: As temperature increases, metals expand due to heat. Bearings, which are a fundamental component of rotating equipment, are highly sensitive to temperature. There are many types of bearings; we will briefly introduce two categories: rolling bearings and sliding bearings. Let’s first briefly discuss the advantages and disadvantages of the two types of bearings! Rolling bearings: Advantages include low cost, low rotational resistance and minimal heat generation, as well as simple lubrication. Disadvantage: poor load-bearing capacity ； Sliding bearing: Advantages include good load-bearing capacity and simple structure; disadvantages include difficulties in lubrication, high rotational resistance and significant heat generation, usually requiring cooling water, as well as high cost. Let’s take a closer look at the structure of rolling bearings and sliding bearings. When the temperature of a bearing rises, its inner and outer rings, cage, and steel balls all expand. During rotation, the lubricant also thins due to the increased temperature, which reduces its ability to adhere to the metal surfaces; as a result, friction increases. This can lead to three situations: 1. The inner side of the outer ring of the bearing is worn by the steel balls, a condition commonly referred to as outer circle wear ； 2. The inner surface of the bearing inner ring is worn by the rotor shaft, commonly known as wear of the inner circle ； 3. Wear of the cage, along with the lack of fixation of the steel balls, leads to their scattering; this is commonly referred to as bearing failure. Speaking of this, another major flaw comes into play: excessive vibration. Mechanical vibration refers to the regular back-and-forth motion of an object around its equilibrium position. Vibrations are divided into three categories: 1. Horizontal vibration: similar to a fish swaying its tail from side to side, usually represented by the symbol “—” ； 2. Vertical vibration: Similar to a bird flapping its wings up and down, usually represented by the “⊥” symbol ； 3. Axial vibration: Similar to piston motion (don’t think dirty things! ), usually represented by the “⊙” symbol. Well, that’s pretty much all there is to say. It’s time for inspections now; for example, inspecting a motor: Method: Look, listen, ask, feel? No, no, that’s traditional Chinese medicine. First, one should check the motor’s nameplate to determine its speed. Generally, motor speeds are divided into three ranges: 500–1000 rpm, 1000–1500 rpm, and 1500–3000 rpm. It is by using these speeds that it is possible to determine whether the vibration and temperature levels of the equipment are within acceptable limits. Secondly, “smelling” involves detecting odors; usually, insulation that has heated up or lubricants exposed to high temperatures emit unusual smells, and experienced workers can tell this just by smelling them. Furthermore, one should use a temperature gauge to check the temperature of the motor, especially at the bearing area. By listening carefully, it is possible to determine whether there are any abnormal noises coming from the motor bearings; healthy bearings produce a clear and steady sound. Finally, there is “pulse measurement”: the horizontal, vertical, and axial vibration values are determined using seismological instruments. Once the data is recorded, diagnosis can begin. Generally, the standard values for motor inspection are as follows: at 500–1000 rpm, the temperature should generally not exceed 60–70°C, and vibration should not exceed 0.1 mm. At 1000–1500 rpm, the temperature should generally not exceed 70–80°C, with vibration not exceeding 0.07 mm. At 1500–3000 rpm, the temperature should generally not exceed 80–90°C, and vibration should not exceed 0.05 mm. In some units, vibration is measured in mm/s; this value represents speed. The inspection criteria depend on specific circumstances, but here the values are given in millimeters. Of course, beyond these limits, the motor under your management will more or less have some issues, and in such cases it is necessary to use a micro-reporting system to inform the maintenance staff about the defects in the motor. By integrating the concept of the inspection system, we can list various issues related to inspection work and address them one by one using scientific methods, thereby creating a sound equipment management system for the enterprise. Some of these issues are listed below: 1. How should one get started with inspection work? With the upgrade carried out in early October, a inspection function was added. By using inspection management to proceed step by step, we can start carrying out inspection tasks. 2. What are the advantages of using a micro-maintenance inspection plan? 1. “Full coverage”: In the previous versions of Micro-Maintenance, when we imported the equipment located throughout the factory premises, we entered that equipment information into the Micro-Maintenance system. By then formulating inspection plans based on each workshop, area, piece of equipment, and the corresponding inspection standards, it became possible to achieve full coverage of the entire factory area, with no gaps or overlooked areas.

2. “Execution capability”: After the inspection plans are established, the personnel responsible for inspecting the equipment can clearly know, depending on their shift, which areas need to be inspected. This ensures that everyone is utilized effectively, inspections are not repeated, and the inspection plans are carried out accurately ； 3. \"Sense of value\": Micro-maintenance offers a paid service to meet the needs of routine inspections. Do not underestimate this aspect of payment, as Nobel Prize in Economics laureate Friedman once said, \"It is most economical to use one’s own money to handle one’s own affairs.\" ； Spending one’s own money to have someone do things is the most efficient way ； Using someone else’s money to do things for oneself is the most wasteful thing ； Using someone else’s money to do things for them is the most irresponsible thing. ”Therefore, for us inspectors, the small amount of money we pay when Micro-Maintenance helps us create a perfect inspection plan becomes less significant. I believe that by mentioning the need to pay, you can also help your boss gain a completely new understanding of the value of your work, after all, knowledge is priceless. 4. “Timeliness” – this is, in my opinion, the most important advantage. In the Internet era, apps such as Didi, Taobao, and Meituan place great emphasis on timeliness, and this is also the core value of the inspection function in MicroMaintenance. In the past, we relied on various paper-based record books according to inspection plans; by the time a defect was reported to the maintenance staff, a considerable amount of time had already passed. With MicroMaintenance’s inspection function, our dedicated inspectors can quickly submit defects to the relevant personnel, and visual dashboards can be used to monitor data such as the failure rate and completion rate, thereby improving equipment management and enabling the equipment to serve the company better. Next, we will introduce the specific standards for some of the relevant functions in micro-maintenance inspection management. During the planning of inspection schedules, it is necessary to determine the frequency at which equipment should be inspected. Generally, for rotating equipment with different speeds, the inspection frequency for temperature and vibration levels is as follows: for speeds of 500–1000 r/min, inspections should be carried out once or twice a week, with oil checks required at least once every six months; for speeds of 1000–1500 r/min, inspections should be done once every two days, with oil checks required at least once every three months; and for speeds of 1500–3000 r/min, inspections should be conducted once or twice a day, with oil checks required at least once a month. As for other items, such as anchor bolts and rotor insulation, these are typically inspected during regular major maintenance sessions. Here’s another bit of little knowledge! When applying lithium-based greases (commonly known as grease) to bearings, if it’s not possible to see the level of grease, too much grease can cause the equipment’s temperature to rise, while too little grease requires more frequent applications, increasing the workload. We can estimate the amount of grease needed using the formula: bearing diameter * bearing width / 2 (in mm); the resulting value, converted to grams, gives an approximate amount of grease required. Additionally, a manual grease gun typically dispenses about 70 grams of grease per press, while a foot-operated grease gun dispenses around 220 grams per press. Based on this, we can determine how many times we need to use the manual or foot-operated grease gun in order to apply the appropriate amount of grease. Since the equipment in different industries varies, and managing such equipment requires a high degree of precision, the information I have provided here is intended solely for reference. I would be honored if it were useful to you; should it not be helpful, I kindly ask for your valuable feedback.