Air compressor operating temperature control and tripping problem solving

1 Working principle of air compressor The screw air compressor is a volumetric air compressor, which achieves the purpose of gas compression by gradually reducing the working volume. The working volume of the screw air compressor is composed of a pair of slots of a rotor which are placed in parallel with each other and mesh with each other, and a casing which accommodates the pair of rotors. When the machine is running, the teeth of the two rotors are inserted into each other's tooth slots, and the teeth inserted into the tooth grooves of the other side move toward the exhaust end as the rotation of the rotor rotates, so that the volume enclosed by the other teeth is gradually reduced, and the pressure is gradually increased until the position is reached. At the required pressure, the cogging side communicates with the exhaust port to achieve exhaust.

When one tooth groove is inserted into the tooth which is engaged with the tooth, two spaces separated by the teeth are formed, the tooth groove close to the suction end is the suction volume, and the volume close to the exhaust end is the volume of the compressed gas. With the operation of the air compressor, the teeth of the opposite rotor inserted into the tooth gap move toward the exhaust end, so that the suction volume is continuously expanded, and the volume of the compressed gas is continuously reduced, thereby realizing the inspiratory compression process in each of the slots. When the pressure of the compressed gas in the cogging reaches the required discharge pressure, the gullet is just in communication with the vent opening and the venting process begins. The change in the suction volume and the compression volume divided by the teeth of the rotor of the other rotor is repeated, and the air compressor continuously inhales, compresses and exhausts.

During the air suction process, air is drawn into the compression chamber via the filter and mixed with the lubricating oil injected into the main engine. During the compression process, the volume of the compression chamber is gradually reduced, and the pressure is gradually increased, after which the oil and gas mixture is discharged through the exhaust port.

Air compressors are transmission machinery. High-speed equipment will generate high temperature if it is not properly lubricated or cooled. Excessive temperature will change the physical coefficient of the rotor and bearing materials. In severe cases, the whole host will burn out. .

Large air compressors are fixed equipment and safety protection is very important. If the over-temperature is severe and the safety protection is not in place, the entire host will be burned and there is a serious consequence of the explosion of the equipment. Old-fashioned piston air compressors are difficult to achieve safety protection, while screw air compressors are equipped with frequency converters, which use inverters to change the speed and adjust the air compressor exhaust volume to achieve constant discharge pressure. At the same time, the electronic protection is complete, the equipment is slightly abnormal, it will automatically stop, that is, trip, and display the fault record on the display, providing a basis for maintenance and repair.

2 Air compressor exhaust temperature control When the air compressor temperature is higher than 80 ft, the temperature control valve will automatically open, the oil will be cooled by the radiator, and the air compressor temperature will drop. When the air compressor exhaust temperature is lower than 75*C for a long time, a lot of condensed water will be generated. If the condensed water cannot be discharged in time, it will enter the air compressor lubricating oil system, causing the lubricating oil to emulsifie and deteriorate, which leads to the air compressor. Parts such as bearings are rusted and affect the service life.

2.1 The possible reasons for the air compressor exhaust temperature below 75 and the corresponding treatment measures 2.1.1 The amount of cooling water is too large, the amount of cooling water is too large, not only causes waste, but also causes the temperature of the papermaking chemical gas to be lower than 75 ft. Adjust the cooling water outlet valve in time; if it is an air-cooled cooler, reduce the cooling area of ​​the cooler.

2.1.2 Ring i temperature is low. Take measures: Increase the ambient temperature appropriately.

23 Oil flow is too large to take measures: adjust the small oil flow control valve.

24 exhaust thermometer not correct measures: replace the exhaust thermometer.

2.1.5 Temperature control valve failure, always in the open position Take measures: replace the temperature control valve.

2.2 The possible reasons for the exhaust gas temperature of the air compressor unit over the 110t setting and the corresponding measures taken 2.2.1 The amount of lubricating oil in the unit is insufficient. The oil level in the oil sight glass is lower than the scale green area.) The air compressor is in The oil level should be kept at more than two-thirds when loading, and must be seen when loading. If there is no oil in the pipeline during shutdown or unloading, the oil will return to the oil and gas tank. At this time, the oil level is not accurate.

Take measures: check the oil surface in time. If it is lower than *L*, please stop and refuel to *H*. 2.2.2 Ambient temperature exceeds the specified range 38T Take measures: increase exhaust air and lower room temperature.

2.2.3 Oil cooler The heat dissipating fin is blocked by dust. It is necessary to take measures from the inside to the outside: check the temperature difference between the inlet and outlet of the oil cooler. The normal temperature difference is 5 ft. If it is greater than 9 ft, the oil cooler may be blocked and removed. Drug cleaning.

2.2.4 Incorrect oil specifications The type of lubricant used in each type of air compressor may be different. Lubricants that meet the equipment requirements must be selected. Otherwise check the oil number and replace the oil.

2.2.5 Temperature control valve failure The temperature control valve functions as a constant temperature control. When the oil temperature measured by the temperature control valve temperature sensing element is lower than the action value (the temperature sensing element action value is generally 71 feet), the lubricating oil directly from the oil and gas The barrel returns to the main machine. When the oil temperature measured by the temperature sensing element of the temperature control valve is higher than the action value, the temperature control valve sensible element ejector action, pushing the valve core to open the bypass valve of its own equipment, so that the lubricating oil enters the oil cooler Cooling (if the temperature measured by the temperature sensing element is higher, the bypass valve is opened more), and the cooled lubricating oil is returned to the main unit. It can be seen that temperature control is very important. When a fault occurs, it should be checked in time whether the oil has been cooled by the oil cooler. If not, replace the heat control valve.

2.2.6 Imported air filter When the dirty air filter is blocked, the intake air is small, and when it is unloaded, the intake valve is closed, and the valve hole is inhaled, generating a small amount of compressed air to ensure The circulation speed of the oil inside the air compressor. At this time, the dust in the intake air is blocked in the filter to prevent the air compressor from being worn prematurely and the oil separator being blocked, usually running at 1000 h or 1a. After that, replace the air filter. In dusty areas, reduce the interval between replacements. The filter must be shut down during maintenance. To reduce downtime, replace it with a new or cleaned spare filter.

The steps for cleaning the inlet air filter are as follows: (1) Tap the flat faces to tap the ends of the filter to remove most of the heavy dry sand; (2) Apply pressure Dry air of less than 0.2 MPa is blown in the opposite direction of the suction air (from the inside to the outside), the nozzle is at least 25 mm away from the folded paper, and is blown up and down in the direction; (3) If there is grease on the filter element, the new filter element should be replaced. (4) Place the illuminator in the filter for inspection. If it is found to be thin, pinholes or damage should be discarded; clean the air filter with low-pressure air. 2.2.7 Oil filter core blockage The oil supply passage should be unobstructed and ensure normal lubrication, which is a way to reduce heat generation. Therefore, if it is found that the oil filter core is clogged, the oil filter should be replaced in time.

2.2.8 Air cooler air duct obstruction, or cooling fan failure The radiator blockage will cause the oil not to be cooled when passing through the radiator, and the oil temperature will rise, causing the air compressor temperature to rise.

Take action: Clean the cooler with low pressure air or replace the cooling fan.

2.2.9 Temperature switch failure Take measures: repair or replace.

2.2.10 Temperature sensor Therefore | 5 early measures: timely replacement.

2.2.11 Cooling water: Insufficient measures: Check the temperature difference between the inlet and outlet pipes, whether the water pressure of the cooling water is low, and whether there is scale.

2.2.12 Cooling Water Temperature Bureau Take measures: Check the inlet water temperature and make the necessary adjustments.

2.2.13 Too little oil flow Injection of an appropriate amount of Atlas air compressor oil into the compression chamber of a single screw air compressor can effectively cool and seal the gas in the compression chamber and form a good relationship between the screw and the star wheel. lubricating. The Atlas air compressor oil injected into the compression chamber greatly increases the heat exchange area between the oil and gas due to atomization, and has a strong cooling effect on the compressed high temperature gas, which greatly reduces the exhaust gas temperature and operates the air compressor. The reliability is significantly improved; after the lubricating oil is injected into the compression chamber, it will enter the leakage gap of the compression chamber, effectively blocking the leakage of high-pressure gas, thereby reducing the energy loss during gas compression; due to the good lubricating properties of the oil, the injection The lubricating oil in the compression chamber enters the screw-star wheel meshing section Aegean. The control of the operating temperature of the air compressor and the solution of the tripping problem form a lubricating oil film between them, which reduces friction and wear and prolongs the use time of the star wheel. On the other hand, the presence of oil increases the loss of viscous shearing, friction, agitation and inhalation preheating, increases the power consumption of the air compressor, and affects the performance of the air compressor. Therefore, the amount of lubricating oil sprayed into the air compressor should be optimal.

It can be seen that when the oil flow rate is too small, the oil flow regulating valve should be adjusted to the appropriate position in time.

3 Air compressor temperature control reduces the heat generated by the air compressor, ensuring the quality of the machine installation or maintenance, in order to reduce heat generation.

Control the exhaust temperature below the set value (here is 100 feet).

Check the main rotor for abnormal noise (friction heat generation). The heat dissipation of the air compressor should be normal: whether it is air-cooled or water-cooled, the cooling passage should be unimpeded, the cooling medium should flow quickly, the flow rate of the cooling medium should be appropriate, too much is waste, too little will not be able to cool.

4 The reason for the air compressor tripping and the corresponding measures taken continuously, the air compressor is continuously operated, the exhaust temperature is increased, when it reaches a certain level (can be set according to the operating environment, the system is set to 100*), the fan Start running, used to reduce the working temperature of the host, the fan runs for a period of time, the host temperature decreases, when the temperature drops to 75 feet, the fan stops.

The problem we encountered was that the operating air compressor often tripped during hot weather in summer, causing the paper machine to suddenly stop. Since we are making paper from grass raw materials, the paper strength is poor. Therefore, the long net machine needs to take the lead several times after stopping every time, even pulling the chartered car, the labor intensity is increased, water, electricity and steam are wasted, which seriously affects the output. After investigation, it was found that the self-tripping of the air compressor was caused by the high exhaust gas temperature (when the air compressor room temperature reached 3,738 ft, the air compressor reached the tripping temperature of 100 ft and the air compressor tripped). Since the system temperature setting has reached the upper limit, it is no longer possible to solve the tripping problem by increasing the system temperature setting.

Take measures: use the tunnel excavated in the 1960s to introduce the tunnel wind into the air compressor room, and reduce the temperature in the air compressor room by about 8 feet without increasing the cost, so that the air compressor exhaust temperature is reduced to About 92 feet, lower than the trip temperature, effectively solve the problem of air compressor self-tripping.

5 Conclusion To ensure the normal operation of the air compressor, we must first understand its working principle, in order to carry out effective maintenance and ensure its normal operation. The control of air compressor temperature and exhaust temperature is very important. If the air compressor exhaust temperature is too high or too low, it will cause damage to the air compressor and trip in severe cases. During the operation, parameters such as operating voltage, current, outlet gas pressure, outlet exhaust temperature and oil level of the air compressor should be recorded regularly to provide basis for maintenance. The exhaust temperature of the air compressor should be controlled at 75110 feet to ensure the normal operation of the air compressor, so as to ensure the normal operation of the paper machine.

To: pulp and papermaking process and paper chemicals; E-mail: daq670129163.com. Format: Duan Aiqin. Air compressor operating temperature control and tripping problem solving several paper chemicals, 2012, 24): 37-39. 2011 global paper and paperboard production record according to the "Global Pulp and Paper Statistics 2012" released by Ruisi Summary>: Although production in North America, Europe and Africa has declined, positive growth in Asia, Latin America, Oceania and the Middle East has led to a new record of 399 million tons of global paper and board production in 2011.

According to senior economists at the World Recording Paper Division, China has ranked first in terms of total paper and board demand and total production for three consecutive years, while the US remains in second place. In 2011, China's total paper and paperboard demand accounted for 24% of the world's total paper and paperboard demand. Paper and board production accounted for 25% of global paper and board production. However, from the perspective of pulp production, the United States in 2011 was 4970. The output of 10,000 tons has maintained the number one position in the world's pulp producing countries. China's pulp production is 19.5 million tons, ranking second. Li Haiming) Tianma Jinghua announced its third quarter 2012 operating results. So far, the only domestic paper chemicals listed company, Suzhou Tianma Fine Chemicals Co., Ltd. announced this year. The third quarter report showed that the total operating income in the third quarter was 238 million yuan and the net profit was 15.3 million yuan. In May, the total operating income was 501 million yuan and the net profit was 26.67 million yuan. The company expects net profit for 2012 to increase by 20% from last year. The main reason for the limited growth in performance is that the company's 2012 acquisition of Tianan Chemical and Nabaiyuan Chemical has been integrated into the operation and management, resulting in a significant increase in costs; the production cost of the GMP certification of the raw materials in the Tianma Refined Suzhou plant. As the corresponding raw materials have not been put into production, the gross profit margin of the products has been squeezed; the company has adjusted the production layout of the leading product AKD raw powder, and the production and sales of AKD raw powder have been affected. Heart-to-heart)

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