High-pressure screw compressor
By using a thrust disc pretensioner in a high-pressure screw compressor, the pretension force is accurately applied by using the friction of the push bolt, the problem that traditional locking round nuts cannot accurately apply sufficient pretension force under high-pressure conditions is solved, and higher pretension force and more uniform thread load are achieved.
Patent Information
- Application Number
- CN202421778334.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-25
- Publication Date
- 2025-05-30
- Estimated Expiration
- 2034-07-25
AI Technical Summary
In the high-pressure screw compressor, the traditional locking round nut compression method cannot accurately apply sufficient preload force, resulting in the thrust disc that may disengage the rotor's shoulder, causing the thrust bearing to be loaded and the rotor threads to be damaged.
A thrust disc pretensioner is adopted, including a nut body and at least four push bolts, and the pretension force is accurately applied through a constant torque wrench. The friction diameter of the push bolt is small, and a large push bolt can be achieved with a smaller torque.
Accurate pretension of the thrust disc is achieved, ensuring that a sufficient pretension force can be applied under high pressure conditions, avoiding the problems of thrust disc disengagement and bearing bias, and improving the strength and uniformity of the threaded connection.
Smart Images
Figure CN222924607U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of compressors. Background Art
[0002] Under the normal working condition of the compressor, the direction of the gas axial force received by the rotor is from the exhaust end to the suction end. In the existing compressor products, in order to balance the gas axial force received by the rotor, a thrust disc is usually installed at the exhaust end of the rotor. The thrust disc is pressed against the shoulder of the rotor shaft by a locking round nut screwed onto the rotor. The mating surface of the thrust disc and the thrust bearing bears the axial force of the rotor, and the axial force is finally transmitted to the locking round nut.
[0003] For a high-pressure screw compressor (gas pressure above 2.5 MPa), the higher gas pressure causes a greater axial force on the rotor. At this time, it is required that the pre-tightening force between the thrust disc and the rotor shoulder is also large enough. Otherwise, during the normal operation of the main engine, the thrust disc may disengage from the rotor shoulder, causing uneven loading of the thrust bearing and damage to the rotor thread. The traditional method of pressing the thrust disc with a locking round nut has the following disadvantages when applied to high-pressure working conditions: Since the required rated pre-tightening torque of the locking round nut is large, the rated tightening torque of the round nut cannot be achieved by using an extended lever arm. During assembly, only a round nut wrench can be used, and the pre-tightening is achieved by knocking on the round nut wrench. This method cannot quantify the pre-tightening force. If the knocking force is small, the pre-tightening force of the locking round nut is insufficient. If the knocking force is large, the threads will be jammed during the process of tightening the locking round nut. Summary of the Invention
[0004] The technical problem to be solved by the utility model is to provide a high-pressure screw compressor that can accurately apply a pre-tightening force to the thrust disc, and the pre-tightening force can be applied large enough.
[0005] A high-pressure screw compressor according to an embodiment of the utility model includes a housing, a male rotor, and a female rotor. A thrust disc is installed at the exhaust end of each rotor, and the inner end face of the thrust disc abuts against the shoulder of the rotor. The feature is that a thrust disc pre-tightener is also installed at the exhaust end of each rotor. The thrust disc pre-tightener includes a nut body and at least four jacking bolts; the nut body is spirally sleeved outside the rotor and is located outside the thrust disc. At least four threaded through holes, the same number as the number of jacking bolts, are opened on the outer end face of the nut body, and the at least four threaded through holes are evenly distributed along the circumferential direction of the nut body; at least four jacking bolts are respectively spirally connected to the at least four threaded through holes in a one-to-one correspondence, and the top end of each jacking bolt abuts against the outer end face of the thrust disc.
[0006] Compared with the prior art, the utility model has the following advantages and features:
[0007] 1. In the embodiment of the present utility model, a thrust disk pre-tightener is used to replace the traditional round nut. The friction diameter of the jacking bolt is small, and a constant-torque wrench can be used to accurately apply the pre-tightening force. A large jacking force can be achieved with a small torque, and a powerful pre-tightening force can be generated by tightening multiple jacking bolts.
[0008] 2. The nut body of the thrust disk pre-tightener in the embodiment of the present utility model has the advantages of a suspended nut. Compared with the traditional round nut, the load distribution on the thread teeth is more uniform, and the thread connection strength is higher. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Figures 1 to 3 The front view schematic diagram, top view schematic diagram, and sectional view schematic diagram of a high-pressure screw compressor according to an embodiment of the present utility model are respectively shown.
[0010] Figure 4 The structural schematic diagram of the suction seat according to an embodiment of the present utility model is shown.
[0011] Figure 5 The structural schematic diagram of the cylinder block and the exhaust seat according to an embodiment of the present utility model is shown.
[0012] Figure 6 The structural external shape schematic diagram of the female rotor and the male rotor according to an embodiment of the present utility model is shown.
[0013] Figure 7 The schematic diagram of the end face tooth profile of the female rotor and the male rotor according to an embodiment of the present utility model is shown.
[0014] Figure 8 The partial sectional view schematic diagram of the thrust disk pre-tightener according to an embodiment of the present utility model is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0015] The following further describes the present utility model with reference to the accompanying drawings.
[0016] Please refer to Figures 1 to 8 . The high-pressure screw compressor according to an embodiment of the present utility model includes a housing 1, a male rotor 21, and a female rotor 22.
[0017] In this embodiment, the housing 1 includes a suction end cover 1a, a suction seat 1b, a cylinder block 1c, an exhaust seat 1d, and an exhaust end cover 1e that are connected in sequence. An axial suction orifice is provided on the suction seat 1b, and an axial exhaust orifice, a radial exhaust orifice, and a radial suction orifice are provided on the cylinder block 1c. Among them, the cylinder block 1c and the exhaust seat 1d are integrally cast. Compared with the structure in which the cylinder block and the exhaust seat are provided as two independent parts, the housing structure of this embodiment ensures concentricity, reduces processing and assembly errors, simplifies the assembly process, and the housing can also be more resistant to high pressure and prevent process gas leakage.
[0018] The male rotor 21 and the female rotor 22 mesh with each other in parallel. Both ends of the male rotor 21 and both ends of the female rotor 22 are rotatably mounted on the housing 1 respectively. In this embodiment, a radial bearing 31 is sleeved at the suction end of each rotor, and a combined radial-thrust bearing 32 is sleeved at the discharge end of each rotor. The radial bearing radially positions the rotor and bears the radial force of the rotor; the thrust bearing axially positions the rotor and bears the axial force of the rotor. Preferably, the radial bearing 31 and the combined radial-thrust bearing 32 adopt sliding bearings. The radial bearing 31 installed at the suction end of the rotor and the radial bearing in the combined radial-thrust bearing 32 both adopt two-lobe journal bearings, and the thrust bearing in the combined radial-thrust bearing adopts a tilting pad bearing. The thrust bearing adopts a tilting pad bearing, and the stability of the bearing is relatively good at high speeds, and the oil film is not easily unstable. The operation of the bearing requires lubricating oil, and lubricating oil holes are opened on the compressor housing and the bearing seat.
[0019] A shaft seal 4 is provided between the bearing at each end of each rotor and the working chamber 10 of the compressor. The shaft seal 4 is used to isolate the medium gas from the lubricating oil system. On the one hand, it prevents the medium gas from leaking into the lubricating oil system and damaging the lubricating oil quality. On the other hand, it prevents the lubricating oil from leaking into the medium gas and polluting the medium gas. In some specific embodiments, the shaft seal 4 adopts a labyrinth seal plus a tandem dry gas seal. The primary seal gas adopts the clean process gas at the outlet of the compressor, bears all the medium pressure, and nitrogen will not be mixed into the process gas system; the secondary seal gas adopts nitrogen, bears a relatively low pressure during operation, and has low requirements for the pressure of nitrogen; the isolation gas is used to block the oil mist and prevent the oil mist from entering the seal and causing seal damage, and the isolation gas also adopts nitrogen.
[0020] A thrust disc 5 and a thrust disc pre-tightener 6 are also installed at the discharge end of each rotor. The inner end face of the thrust disc 5 abuts against the shaft shoulder 23 of the rotor. The combined radial-thrust bearing 32 is located inside the thrust disc 5, and the thrust bearing in the combined radial-thrust bearing 32 is close to the thrust disc 5.
[0021] The thrust disc pre-tightener 6 includes a nut body 61 and at least four thrust bolts 62. The nut body 61 is helically sleeved on the outside of the rotor and is located outside the thrust disc 5. At least four threaded through holes 63, the same number as the number of the thrust bolts 62, are opened on the outer end face of the nut body 61, and the at least four threaded through holes 63 are evenly distributed along the circumferential direction of the nut body 61. At least four thrust bolts are respectively helically connected to the at least four threaded through holes 63 in one-to-one correspondence, and the top ends of the thrust bolts 62 abut against the outer end face of the thrust disc 5. The thrust disc pre-tightener 6 presses the thrust disc 5 against the shaft shoulder 23 of the rotor, and the axial force of the rotor is borne through the cooperation of the thrust disc 5 and the thrust bearing in the combined radial-thrust bearing 32, and the axial force is finally transmitted to the thrust disc pre-tightener 6. The specific number of the thrust bolts 62 is determined according to the total pre-tightening force required to be applied to the thrust disc and the pre-tightening force that each thrust bolt can apply. Preferably, the number of the thrust bolts 62 is six to twelve.
[0022] When installing the thrust disc pre-tightener 6, first screw the nut body 61 onto the rotor to press the thrust disc 5. Then screw the nut body 61 back to keep a little clearance between the nut body 61 and the thrust disc 5. Use a torque wrench to tighten the jacking bolt 62. The jacking force of the jacking bolt 62 acts on the thrust disc 5, and the reaction force acts on the nut body 61. The jacking force can generate a strong pre-tightening force between the thrust disc 5 and the rotor shoulder 23. Since each jacking bolt 62 is tightened with a torque wrench, the pre-tightening force can be accurately applied, and a strong pre-tightening force can be generated by tightening multiple jacking bolts 62.
[0023] In this embodiment, the tooth number ratio of the male rotor 21 to the female rotor 22 is 5:7. Compared with the conventional screw rotor with a tooth number ratio of 4:6 for the male rotor and the female rotor, the bottom diameter of the rotor is larger, and the shaft diameters of the sealing section and the bearing section can be designed larger. This improves the rotor strength, reduces the bearing specific pressure, and enables the compressor to withstand the load under high-pressure working conditions.
[0024] In this embodiment, the high-pressure screw compressor is an oil-free liquid-injected process gas twin-screw compressor. The oil-free liquid-injected process gas twin-screw compressor includes a synchronous pinion 71 and a synchronous gear 72. The synchronous pinion 71 is installed at the suction end of the male rotor 21, and the synchronous gear 72 is installed at the suction end of the female rotor 22. The synchronous pinion 71 and the synchronous gear 72 mesh with each other.
[0025] The male rotor 21 is connected to the prime mover. The male rotor 21 drives the female rotor 22 to rotate through the synchronous pinion 71 and the synchronous gear 72, and the male and female rotors do not contact each other. Preferably, the synchronous gear 72 adopts a thick-thin tooth structure. The synchronous gear 72 includes a thick tooth ring, a thin tooth ring, and a hub. Both the thick tooth ring and the thin tooth ring are sleeved on the hub, and the clearance between the male and female rotors is ensured by adjusting the staggered angle between the thick tooth ring and the thin tooth ring.
[0026] When the high-pressure screw compressor works, the suction, compression, and exhaust processes are completed by the rotary motion of the working volume between the male and female rotors, realizing the pressurization of the process gas.
Claims
1. A high-pressure screw compressor, comprising a housing, a male rotor and a female rotor, wherein a thrust plate is mounted at the exhaust end of each rotor, wherein the inner end surface of the thrust plate abuts against the shaft shoulder of the rotor, wherein: A thrust disc preloader is also installed at the exhaust end of each rotor, and the thrust disc preloader includes a nut body and at least four thrust bolts; The nut body is spirally sleeved outside the rotor and located outside the thrust plate. The outer end surface of the nut body is provided with at least four threaded through holes, the number of which is the same as the number of the thrust bolts. The at least four threaded through holes are evenly distributed along the circumferential direction of the nut body. The at least four thrust bolts are respectively and one by one screw-connected with the at least four threaded through holes, and the top end of each thrust bolt abuts against the outer end surface of the thrust plate.
2. A high pressure screw compressor according to claim 1, characterized in that: The number of the jacking bolts is six to twelve.
3. A high pressure screw compressor according to claim 1, characterized in that: The shell comprises an air intake end cover, an air intake seat, a cylinder body, an exhaust seat and an exhaust end cover which are connected in sequence, and the cylinder body and the exhaust seat are integrally cast.
4. A high pressure screw compressor according to claim 1, characterized in that: The gear ratio of the male rotor to the female rotor is 5:
7.
5. The high-pressure screw compressor according to claim 1, characterized in that: The suction end sleeve of each rotor is provided with a radial bearing, and the exhaust end sleeve of each rotor is provided with a radial thrust joint bearing, and the radial thrust joint bearing is located on the inner side of the thrust plate.
6. A high pressure screw compressor according to claim 5, characterized in that: The radial bearing installed at the suction end of the rotor and the radial bearing in the radial thrust combined bearing both adopt two-oil-leaf cylindrical bearings; The thrust bearing in the radial thrust combined bearing adopts a tilting pad bearing.
7. A high pressure screw compressor according to claim 1, characterized in that: The high-pressure screw compressor is an oil-free liquid injection process gas twin-screw compressor, which includes a synchronous pinion and a synchronous gear. The synchronous pinion is installed at the suction end of the male rotor, and the synchronous gear is installed at the suction end of the female rotor. The synchronous pinion and the synchronous gear are meshed with each other.