【Mechanical Equipment Technology Edition】Daily Question 201803022: Screw Refrigeration Compressors — Basic Structure and Characteristics (4)
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This post was last edited by YORK Industrial Refrigeration on 2018-3-26 at 15:21. This year’s 【Daily Question】is divided into three categories: screw refrigeration compressors, refrigeration systems, and oil circuits, aiming to provide a comprehensive understanding of refrigeration technology. (If you encounter something you don’t know or can’t answer, please actively look up information; by doing so, your skills will improve!) ) All participants in the comments on this post will receive 1-3 wealth points; those who give complete answers will receive 10-15 points, with the validity period being two days. ============================== Basic structure and characteristics of screw refrigeration compressors (4): The principle and forces acting on the oil pressure balance piston. 1. The function of the balance piston is to balance the axial force on the rotor. 2. Working principle of the balance piston: On both sides of the rotor in a screw compressor, an axial force directed toward the intake side exists due to the pressure difference between the intake and exhaust gases. The balance piston exerts an opposite axial force on the rotor under the action of oil pressure (around 0.5 MPa). Thus achieving balance. The horizontal piston generally bears 70% of the axial force, with the remainder being carried by the positioning bearings. The balance piston is generally located on the male rotor, as the axial force acting on the male rotor is much greater than that on the female rotor. 3. Force application: One end of the balance piston is subjected to the force exerted by the oil, as well as an axial force in the opposite direction, generated by the pressure difference between the intake and exhaust gases. ============================== High-quality promotions: Mechanical equipment——Videos on the repair and calibration of York compressors https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1806833 Mechanical equipment——Maintenance procedures for York screw compressors https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1806833 Mechanical equipment——Upgrading of York Quinton control centers https://bbs.hcbbs.com/thread-1804837-1-1.html Mechanical equipment——Major repairs of GEA Grasox screw compressors https://bbs.hcbbs.com/thread-1800467-1-1.html Mechanical equipment——Disassembly and maintenance of British HOWDEN screw compressors https://bbs.hcbbs.com/thread-1832529-1-1.html Mechanical equipment——Disassembly and maintenance of Japanese Maekawa MYCOM screw compressors https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=
Due to the structural differences, the axial force acting on the male screw, caused by the pressure difference between the suction and exhaust sides, is much greater than the axial force acting on the female screw. Therefore, in addition to a thrust bearing, an oil-pressure balancing piston is also installed on the male screw to reduce the load exerted by the male screw on the end face of the sliding bearing, thereby reducing the axial force on the thrust bearing.
The function of the balance piston is to counteract the axial force on the rotor. On both sides of the rotor in a screw compressor, an axial force directed toward the intake side exists due to the pressure difference between the intake and exhaust gases. The balance piston exerts an opposite axial force on the rotor under the action of oil pressure. Thus, balance is achieved. The horizontal piston generally bears 70% of the axial force, with the remainder being taken up by the positioning bearings. The balance piston is generally located on the male rotor, as the axial force acting on the male rotor is much greater than that on the female rotor. The comb teeth serve to provide sealing and throttling functions.
The function of the balance piston is to counteract the axial force of the rotor. On both sides of the rotor in a screw compressor, an axial force directed toward the intake side exists due to the pressure difference between the intake and exhaust gases. The balance piston exerts an opposite axial force on the rotor under the action of oil pressure. Thus achieving balance. The horizontal piston generally bears 70% of the axial force, with the remainder being carried by the positioning bearings. The balance piston is generally located on the male rotor, as the axial force acting on the male rotor is much greater than that on the female rotor. The female rotor consists of a sealing disk with staggered teeth on its interior and an external oil supply sealing disk; the oil pressure acts between these two components, similar to a disk placed in a basin with the same inner diameter, where the basin contains high-pressure oil. The function of the staggered teeth is merely to provide sealing, thereby enabling the high-pressure oil to maintain a stable pressure. This oil pressure acts on the disk, which is fixedly installed at the inlet end of the male rotor, thus helping to balance the axial forces.
1. The function of the balance piston is to counteract the axial force on the rotor. 2. Working principle of the balance piston: On both sides of the rotor in a screw compressor, an axial force directed toward the intake side exists due to the pressure difference between the intake and exhaust gases. The balance piston exerts an opposite axial force on the rotor under the action of oil pressure (around 0.5 MPa). Thus achieving balance. The horizontal piston generally bears 70% of the axial force, with the remainder being carried by the positioning bearings. The balance piston is generally located on the male rotor, as the axial force acting on the male rotor is much greater than that on the female rotor. 3. Force application: One end of the balance piston is subjected to the force exerted by the oil, as well as an axial force in the opposite direction, generated by the pressure difference between the intake and exhaust gases.
The balance piston is fixed to one end of the suction side of the driving rotor by bolts (or keys); it rotates together with the rotor within the balance piston sleeve, and uses oil pressure to counteract part of the axial force. Its purpose is to extend the service life of the thrust bearings.
1. High-pressure oil is injected into the oil chamber at the top of the plug, creating a pressure that counteracts the axial force, thereby balancing it. 2. The balance plug is located at the main shaft neck and tail section on the intake side of the rotary piston, and it is used to reduce the load on the bearing surface of the main shaft caused by the pressure difference between the exhaust side and the intake side, as well as to lessen the axial force exerted on the secondary shaft bearings. 3. The use of balanced spacers to balance axial forces can significantly reduce the load on the thrust bearings as well as their geometric dimensions, thereby saving metal consumption.
The balance piston exerts an opposite axial force on the rotor under the action of oil pressure. Thus, balance is achieved. The horizontal piston generally bears 70% of the axial force, with the remainder being taken up by the positioning bearings. The balance piston is generally located on the male rotor, as the axial force acting on the male rotor is much greater than that on the female rotor. The comb teeth serve to provide sealing and throttling functions.
To balance the axial force: In multi-stage centrifugal equipment, such as series-connected centrifugal compressors or multi-stage pumps, the pressure at the end is usually high. Relying solely on thrust bearings to counteract this force is too costly; that’s why this component is added
1. The function of the balance piston is to counteract the axial force on the rotor. 2. Working principle of the balance piston: On both sides of the rotor in a screw compressor, an axial force directed toward the intake side exists due to the pressure difference between the intake and exhaust gases. The balance piston exerts an opposite axial force on the rotor under the action of oil pressure (around 0.5 MPa). Thus achieving balance. The horizontal piston generally bears 70% of the axial force, with the remainder being carried by the positioning bearings. The balance piston is generally located on the male rotor, as the axial force acting on the male rotor is much greater than that on the female rotor. 3. Force application: One end of the balance piston is subjected to the force exerted by the oil, as well as an axial force in the opposite direction, generated by the pressure difference between the intake and exhaust gases.
1. The function of the balance piston is to counteract the axial force on the rotor. 2. Working principle of the balance piston: On both sides of the rotor in a screw compressor, an axial force directed toward the intake side exists due to the pressure difference between the intake and exhaust gases. The balance piston exerts an opposite axial force on the rotor under the action of oil pressure (around 0.5 MPa). Thus achieving balance. The horizontal piston generally bears 70% of the axial force, with the remainder being carried by the positioning bearings. The balance piston is generally located on the male rotor, as the axial force acting on the male rotor is much greater than that on the female rotor. 3. Force application: One end of the balance piston is subjected to the force exerted by the oil, as well as an axial force in the opposite direction, generated by the pressure difference between the intake and exhaust gases.