Compressor is a kind of driven fluid machinery that promotes low pressure gas to high pressure gas. It is the engine of the air source system. In use, it will inevitably encounter various failures, which will seriously affect work. In order to make it easy for everyone to find the cause for repair in the event of a failure, Xiaobian summarized five types of more common air compressor maintenance!
First, the exhaust volume is insufficient
Insufficient displacement is one of the prone to failure of the compressor. Its occurrence is mainly caused by the following reasons:
1. Intake air filter failure: fouling and fouling reduce the amount of exhaust; the suction pipe is too long and the pipe diameter is too small, which increases the suction resistance and affects the air volume. The filter must be cleaned regularly.
2. Decrease in compressor speed reduces exhaust volume: Improper use of air compressors, because the exhaust volume of air compressors is designed according to a certain altitude, intake temperature and humidity. When it is used above the above standards, When the plateau is high, the intake pressure will decrease, and the exhaust volume will inevitably decrease.
3. The cylinders, pistons, and piston rings are severely worn and out of tolerance, which increases the relevant clearances and increases the leakage, which affects the exhaust volume. When it is normal wear and tear, it is necessary to replace wearing parts such as piston rings in a timely manner. If the installation is not correct and the clearance is not suitable, it should be corrected according to the drawing. If there is no drawing, empirical data may be taken. For the clearance between the piston and the cylinder along the circumference, if it is a cast iron piston, the clearance value is the diameter of the cylinder. 0.06 / 100 ～ 0.09 / 100; for aluminum alloy pistons, the clearance is 0.12 / 100 ～ 0.18 / 100 of air diameter; steel pistons can take the smaller value of aluminum alloy pistons.
4. The stuffing box is not strict, and the air leakage is caused to reduce the gas volume. The reason is firstly that the stuffing box itself is not manufactured properly; secondly, it may be due to the misalignment of the piston rod and the stuffing box center during installation, resulting in air leakage due to wear and tear; generally, the lubricant is filled at the stuffing box. , It can play the role of lubrication, sealing and cooling.
5. The impact of the failure of the compressor suction and exhaust valves on the exhaust volume. Metal fragments or other debris have fallen between the valve seat and the valve disc, resulting in improper closing and leakage. This not only affects the displacement, but also changes in interstage pressure and temperature? This problem may occur due to manufacturing quality issues, such as valve warpage, and second, due to valve seat and valve wear Severe and leaky.
6. The valve spring force is not well matched with the gas force. If the elastic force is too strong, the valve disc will open slowly. If the elastic force is too weak, the valve disc will not close in time. This not only affects the air volume, but also affects the increase of power and the life of the valve disc and spring. At the same time, it will also affect the changes in gas pressure and temperature.
7. The pressing force of the compressed air valve is improper. If the compression force is small, air leakage is required. Of course, too tight will not work, which will deform and damage the valve cover. The general compression force can be calculated by the following formula: p = kπ / 4 D2P2, D is the diameter of the valve cavity, P2 is the maximum Gas pressure, K is a value greater than 1, generally taken from 1.5 to 2.5, K = 1.5 to 2.0 at low pressure, K = 1.5 to 2.5 at high pressure. Taking K in this way has proved to be good in practice. The air valve is faulty, the valve cover must be hot, and the pressure is abnormal.
Second, the pressure is abnormal: the amount of air discharged from the compressor cannot meet the user's flow requirements at the rated pressure, the exhaust pressure must be reduced. At this point, another machine with the same exhaust pressure and large exhaust volume had to be replaced. The main reason that affects the abnormal pressure between stages is the air leakage of the valve or the wear of the piston ring, so we should find the cause and take measures from these aspects.
Third, the temperature is abnormal: abnormal exhaust temperature means that it is higher than the design value. Theoretically, the factors affecting the increase of exhaust gas temperature are: intake air temperature, pressure ratio, and compression index (for air compression index K = 1.4). The actual situation affects the factors of high suction temperature, such as: low intercooling efficiency, or the scale condensation in the intercooler affects heat exchange, the suction temperature of the latter stage must be high, and the exhaust temperature will also be high. In addition, air leakage from the valve and air from the piston ring will not only affect the rise in exhaust temperature, but also change the interstage pressure. As long as the pressure ratio is higher than normal, the exhaust temperature will increase. In addition, for water-cooled machines, the lack of water or insufficient amount of water will increase the exhaust temperature.
4. Abnormal sound: If some parts of the compressor fail, abnormal sound will be issued. Generally speaking, the operator can judge the abnormal sound. The gap between the piston and the cylinder head is too small and directly hits; the connecting rod of the piston rod and the piston is loose or tripped; the end face of the piston is blocked, and the piston moves up and hits the cylinder head; metal fragments fall into the cylinder and water accumulates in the cylinder, etc. Both can make a knock in the cylinder. The crankshaft bush bolts, nuts, connecting rod bolts, crosshead bolts in the crankcase are loose, tripped, broken, etc., the shaft diameter is severely worn, the clearance is increased, the crosshead pin and the bushing are too large or severely worn, etc. There was an impact sound inside the crankcase. The exhaust valve disc is broken, the valve spring is soft or damaged, the load regulator is not adjusted properly, and so on. It can make a knock in the valve cavity. Find faults and take measures from this.
V. Overheating failure: In the friction place of crankshaft and bearing, crosshead and slide, packing and piston rod, the temperature exceeding the specified value is called overheating. Consequences of overheating: one is to accelerate the wear between the friction pairs, and the other is that the excessive heat energy is continuously accumulated, which will cause the friction surface to burn and cause major machine accidents. The main causes of overheating of the bearing are: uneven contact between the bearing and the journal or the contact area is too small; the bearing is skewed, the crankshaft is bent, the viscosity of the lubricant is too small, the oil circuit is blocked, the oil pump is faulty, and the oil is cut off. , Did not find a good clearance, the main shaft and the motor shaft were not aligned, the two axes are tilted, etc.
By understanding the compressor failure, we can solve the failure in a timely manner and reduce losses when a failure occurs. Of course, these are only common faults. If you cannot solve them during maintenance of the air compressor, you can replace them or send them for repair.
Guangdong Guangye Electromechanical Equipment Engineering Technology Co., Ltd. is an enterprise that integrates agent sales and after-sales maintenance to provide customers with air compressors, vacuum pumps, nitrogen machines and post-processing equipment. Our company is an agent of Bola State of Atlas Group. The company respects credit and abides by contracts to ensure product quality.