Analysis of high temperature shutdown failure of Fusheng SA15-37A air compressor unit

Industrial technology Fusheng SA15-37A air compressor unit high-temperature shutdown failure analysis Wang Zhenlin (China Petroleum United Pipeline Co., Ltd. West part of the company Jiuquan company Gansu Jiuquan body, so that maintenance personnel can have a deep understanding of the air compressor and lifted. At the same time, it can effectively enhance the judgment level of the operator when the unit has a certain fault.

At present, the oil-injected screw air compressor has become the mainstream product in the air compressor, which has the characteristics of reliable performance, low vibration, low noise, high efficiency and no damage to the device, and under the same exhaust pressure, It has more advantages than piston compressors. However, since only the rotors are meshed with each other, the piston does not need to be repeatedly moved, thereby reducing the vibration source and reducing noise.

1 Failure phenomenon At 8 o'clock in the morning, the air compressor was turned off during the operation of the offshore platform. After careful inspection on the site, the main motor overload protection relay was reset. After that, normal loading was initiated, and when loading, a sudden high temperature shutdown occurred. After careful inspection at the site, the electrical control system did not appear any bad or problem, and then started twice, the unit has a high temperature shutdown after a short run, in the oil system After a certain inspection and replacement of the new oil-disconnecting solenoid valve, the test is still in progress.

1-cylinder; 2-transmission gear; 3-cylindrical roller bearing; 4-yang screw; 5-positioning pin; 6-adjusting washer; 7-bearing; 8-thrust bearing; 9-bearing end cap; Screw injection screw compressor structure injection screw compressor structure principle The structure of the oil injection screw compressor is similar, the following figure is the structure of the oil injection screw compressor: (for example) the oil injection screw compressor mainly consists of two The screw and cylinder form a sealed system. The male screw is the active screw and the female screw is the driven screw. The axial force direction of the rotor is directed from the exhaust end to the intake end, and is received by a pair of tapered roller bearings and mounted on the non-drive end. The radial force that the rotor is subjected to is supported by a cylindrical roller bearing and is mounted on the drive end of the rotor as a free end to digest the amount of thermal expansion of the rotor. The motor drives the male screw through the speed increasing gear, and then the male screw drives the female screw.

The working quantity of the screw compressor: the working process of the screw compressor is divided into four stages: suction, sealing, compression and exhaust. When the air is inflated, the male screw and the female screw are disengaged, and the space is increased to form a negative pressure. At this position, the air enters the screw gap. The screw continues to rotate, the gas is sealed in the sealed space formed by the screw and the cylinder, the male screw is equivalent to the piston, the female screw is equivalent to the cylinder sleeve, the body is pushed to the exhaust end and is continuously compressed; when the screw is rotated to the outlet, the sealing is performed The gas in the screw is removed to complete a cycle. When the oil-injected screw compressor works, the pressure generated by itself drives the lubricating oil circulation. The lubricating oil is continuously injected into the screw cylinder and the front and rear bearings, which not only takes away the heat generated by the compressed air, but also lubricates and seals the screw. Therefore, The working life is very long, as long as the maintenance is good, you can continuously move for three to five years to overhaul.

3 Air compressor organization system components and function maintenance personnel to analyze this fault item by item, in order to find out the various factors causing the fault, the air compressor unit is Fusheng SA15-37A type. The following picture shows the system diagram of the oil-injected screw air compressor unit: (for example) the oil-injected screw air compressor unit is powered by the oil-injected screw compressor, the main motor, the oil separator, the cooler, the intake valve, and the minimum pressure. Valves, temperature control valves, steam traps, loading and unloading solenoid valves, air volume regulating valves, oil shutoff solenoid valves, air filters, oil filters, oil and gas separation filters, instrument control systems, etc., can be divided into several according to their working principles. System or loop. 3.1 Oil system The oil system is mainly composed of oil cooler, temperature control valve, oil filter, oil shut-off solenoid valve and pipeline. After the compressor exhaust enters the oil separator, the temperature of the oil is consistent with the temperature of the exhaust gas, and then the temperature of the oil is effectively reduced by the radiator so that it is within a reasonable temperature range. Then, finally enter the compressor for recycling. In order to fully guarantee the relevant performance of the oil, and at the same time, the moisture in the air is continuously condensed, and the temperature of the exhaust gas must be controlled within a certain range. In real life, the temperature of the oil is usually controlled within 70100 ° C, and the maximum temperature is usually not more than 120 ° C. The main role of the temperature control bottom is to maintain the temperature of the oil relatively stable, generally at 65C When it is left or right, it automatically opens.

3.2 Air system intake and after cooling system, which is mainly divided into oil and gas separator, minimum pressure valve, filter and orifice, safety valve, cooler, water separator and discharge pipeline. The compressor forms the pressure inside the cylinder of the oil separator during the compression of the air and oil mixture, and after the oil and gas mixture enters the separator, the gas will pass through the separator core due to the important role of the oil in the container. The top of the container is drained.

4 Fault Analysis From the inspection situation at the site, there seems to be no correlation between the main motor overload and the unit exhaust high temperature shutdown, but the fault happens just in this respect. As can be seen from the table below, the motor overload is largely due to the high compressor discharge pressure. There are two possibilities for high exhaust pressure: one is that the minimum pressure maintains the valve jam, and the other is that the oil in the separator does not flow smoothly. (As shown in Table 1) The final confirmation, the main reason for the main temperature of the head exhaust is due to the blockage caused by the drain pipe, which makes the main motor overload and high temperature of the exhaust have a reasonable explanation. The specific principle for generating this fault is that due to the fact that the oil and gas separator is not cleaned at the time of the annual inspection, a series of troubles and problems are caused.

Conclusion At present, the treatment plants of various oilfields generally adopt the oil-injected screw-type compressor unit. The degree of automation in this way is very high, and the requirements for professional level are also very high during operation and maintenance. Only by fully understanding the air compressor principle and related characteristics of each brand can it be well operated and maintained.

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