How to effectively repair screw wear of screw refrigeration compressor

How to effectively repair screw wear of screw refrigeration compressor

If you want to solve the problem effectively and quickly, you should first find out the cause of the problem, then let's first look at the cause of screw wear in the screw refrigeration compressor.

　　 1. Reasons for screw wear

　　1. The screw rotates in the barrel, and the lubricating oil and compressed gas rub against the screw and the body, causing the working surface of the screw to gradually wear out: the diameter of the screw gradually decreases, and the diameter of the inner hole of the body gradually increases. In this way, the matching diameter gap between the screw and the body increases a little as the two gradually wear. However, because the resistance of the nose and the splitter plate in front of the body has not changed, this increases the leakage flow of the squeezed gas forward, that is, the flow of gas and lubricating oil from the diameter gap to the intake direction increases. As a result, the flow rate of the discharge machine decreases.

　　2. If there are corrosive substances such as acid in the gas, it can accelerate the wear of the screw and the body.

　　3. The abrasion of the machine, or metal foreign matter mixed into the material, suddenly increases the torque of the screw. This torque exceeds the strength limit of the screw and causes the screw to twist. This is an unconventional accident damage.

　　 2. Screw repair

　　1. The twisted screw should be considered according to the actual inner diameter of the body, and the outer diameter deviation of the new screw should be given according to the normal clearance of the body.

　　2. After the surface of the thread with the reduced diameter of the worn screw is treated, it is thermally sprayed with wear-resistant alloy, and then ground to size. This method is generally processed and repaired by a professional spraying factory, and the cost is relatively low.

　　3. Wear-resistant alloy is built-up on the threaded part of the worn screw. According to the degree of screw wear, surfacing welding 1~2mm thick, and then grinding the screw to size. This wear-resistant alloy is composed of materials such as C, Cr, Vi, Co, W, and B to increase the wear resistance and corrosion resistance of the screw. The professional surfacing factory has a high cost for this kind of processing, except for the special requirements of the screw, it is generally rarely used.

　　4. Hard chrome plating can also be used to repair the screw. Chromium is also a wear-resistant and corrosion-resistant metal, but the hard chrome layer is easier to fall off.

　　 Three, body repair

　　The inner surface of the body is harder than the screw, and its damage comes later than the screw. The scrapping of the body is the increase in the inner diameter due to time wear. Its repair method is as follows:

　　1. For the machine body with increased diameter due to wear, if there is a certain nitriding layer, the hole in the machine body can be directly bored and ground to a new diameter size, and then a new screw can be prepared according to this diameter.

　　2. The inner diameter of the machine body is machined and trimmed to recast the alloy, the thickness is between 1~2mm, and then it is finished to size.