Common problems and solutions of piston refrigeration compressors

Common problems and solutions of piston refrigeration compressors

Piston compressors are inconvenient to maintain, but piston compressors have an irreplaceable role in many fields. Therefore, it is very important for many companies to ensure its smooth operation. The analysis and treatment of common problems of piston compressors are summarized below. Method for your reference.

　　 One, hit the cylinder

　　 During the operation and start of the piston compressor, when the piston reaches the inner or outer (or upper and lower) dead points, it directly or indirectly collides with the end surface of the cylinder, which is called "cylinder collision".

problem analysis:

The reasons for cylinder collision are as follows: During compressor operation, the relative position of piston and cylinder changes due to various reasons. When this change is greater than the gap between the piston and the cylinder head, it will happen. The direct collision between the cylinder head and the piston; a large amount of cooling water or lubricating water (for the old oxygen compressor) enters the cylinder, which will cause an indirect collision between the piston and the cylinder head. Cylinder collision caused by this reason is also called a "hydraulic accident" ; Foreign matter enters the cylinder, causing indirect impact between the piston and the cylinder head.

Approach:

　　 During maintenance and installation, strict attention must be paid to the various gaps that can affect the piston position to prevent cylinder collision due to the movement of the piston position. However, under the premise of ensuring the clearance volume, try to reduce the clearance volume, and check and adjust after each overhaul to ensure unobstructed gas flow and improve the efficiency of the entire compressor. In order to prevent hydraulic accidents, in addition to doing a good job in equipment maintenance and plugging various loopholes, be sure to crank and check before starting. Make sure that there is no water in the cylinder before starting the car. It is also necessary to prevent foreign matter from entering the cylinder during maintenance. Crank before starting. During operation, pay attention to the working conditions of the air valve and listen to whether there is any abnormal noise in the cylinder to prevent cylinder collision accidents.

　　 Two, air leak

　　 Failure analysis:

　　As there are gaps in the joints of the relatively moving components in the compressor due to wear, gas leakage is caused. Also, due to the low purity of the gas, frequent suction and discharge will cause great friction on the contact surface, until the suction and exhaust valve leaks. In addition, due to the low quality of the gas and the valve disc, valve seat, and limiter, the joint surface of the valve disc and the valve seat is worn or adhered to grease, which causes the valve to not close tightly and leaks.

Approach:

　　 Regular maintenance can ensure that the compressor does not reduce efficiency. Develop a maintenance and cleaning plan for the suction and exhaust valves, select high-quality valve discs and valve seats, and replace worn valve discs and valve seats in time, clean the existing grease, ensure that the gas is clean and water-free, and make the valve discs and valve seats , The generation limiter runs in the design environment.

　　 Three, the valve (air valve) is stuck

problem analysis:

　　 Valve jams and breaks are caused by poor movement of the valve plate and spring.

Approach:

　　 1) If there is too much sludge in the valve chamber, it may stick to the valve plate and make it inoperative; if the old oxygen compressor lubricated with water, if there is too much dirt in the valve chamber, the valve plate may also be stuck. At this time, the valve and valve chamber should be cleaned;

　　2) If the gap between the inner and outer circles of the annular valve plate and the guide boss is too small, the valve is prone to jamming; and when the edge of the annular valve plate is worn too much, it may become stuck on the guide block. At this time, the valve plate should be replaced;

　　3) The valve center bolt is loose, so that the valve plate cannot be guided normally when it rises and falls, which may cause the valve plate to jam. At this time, remove the valve and tighten the center bolt;

　　4) If the valve spring is wound with a round cross-section steel wire, when the winding is relatively large, the spring coils are prone to misalignment, causing the spring to jam. In this case, the only way to deal with this is to switch to other forms of springs.

　　 Fourth, there is a problem with the spring

problem analysis:

　　 Spring with excessive spring force. This kind of spring causes the valve to close in advance, but lags behind to open, so that the intake and exhaust are small, which not only reduces the overall efficiency of the compressor, but also affects the air supply quality; the spring is fatigued and broken, which makes the valve lift. The scope is directly connected with the gas in the cylinder and the external pipeline, which makes it difficult to increase the gas pressure. These two conditions have obvious effects on the efficiency of the compressor. In addition, improper selection of the spring will result in power loss and increase costs. For example: the spring force is too large, so that the compressor starting current is significantly increased, causing management difficulties.

Approach:

In work, in addition to actual records, most of them judge whether there is air leakage by touching the casing of the suction valve by hand. This method is feasible, but this method cannot know whether there is a problem with the exhaust valve, so detailed maintenance must be performed Planning and operation records. Be sure to strictly control the quality of accessories and choose a spring that meets the requirements of the compressor.

　　 Five, vibration

problem analysis:

　　 The fundamental reason for the vibration of the piston compressor is the alternating load. There are two types of alternating loads acting on the piston compressor device: one is the unbalanced piston inertia force; the other is the interference caused by the discontinuous air supply of the piston compressor and the strong pressure pulsation of the gas pipeline force.

Approach:

　　 For the vibration caused by the imbalance of inertial force, it should be eliminated and reduced as much as possible from the structure of the machine. In addition, strict requirements must be imposed in the design and construction of the compressor foundation, and the installation of the machine must also comply with the regulations, so as to minimize the vibration of the machine, and the horizontal and vertical amplitudes can be kept within the allowable range.

　　 For device vibration caused by airflow pressure pulsation, the following methods are often used to eliminate:

Set up a buffer near the cylinder exhaust pipe connection; set an orifice plate on the gas pipeline. This method is usually used in the pipeline with a long distance from the cylinder to the buffer tank and the connection is long; apply a shock absorber; reasonably install the pipeline fulcrum , The pipeline layout should be as straight as possible, especially to avoid turning at right angles.

　　 Six, cooling system precautions

problem analysis:

During the operation of the compressor, heat is generated by the friction between the piston and the cylinder, and the compression heat generated by the compressed gas of the piston increases the temperature of the cylinder wall and the piston. The increase in temperature will have a great impact on the efficiency and power consumption of the compressed gas and the lubricating oil. When the intake gas is heated and expanded, it will inevitably occupy a part of the cylinder volume, that is to say, the amount of gas drawn into the cylinder each time is less than the amount under normal cooling conditions.

Approach:

　　 According to different working environment and models, set the composition of the compressor cooling system. The cooling system generally consists of three parts: the cylinder cooling system, the lubricating oil cooling system, and the compressed gas cooling system. To achieve a good cooling effect, it is necessary to reduce the temperature of the cooling water, regularly clean the dirt of the cooling system, so as not to reduce the circulation area of ​​the cooling water, and ensure that the cooling water quality is within the national cooling water standards to avoid the cooling system. Fouling, blockage, etc., hinder the exchange of heat, increase the temperature, reduce the cooling efficiency of the equipment, and have a great impact on the safety and economic operation of the compressor. Distributing water has a corrosive effect on the surface of the metal, so it is particularly corrosive, causing it to be difficult to repair after water leakage and huge losses.

　　 Seven, unloading device failure

problem analysis:

　　The oil pressure is not enough or there is dirt in the oil pipe or cylinder.

Approach:

　　 Adjust the oil pressure to 0.15-0.3Mpa or clean the oil pipes and cylinders.