Installation method of compressor double-stage screw and double-stage screw compressor

Abstract

The present application relates to the technical field of screw compressor, especially to a kind of installation method of compressor double-stage screw and double-stage screw compressor.The compressor is except rotor, exhaust seat and cover plate, still includes two pressing plates, two groups of tapered roller bearings, two compression rings and two groups of disc springs, wherein pressing plate, tapered roller bearing, compression ring and disc spring are all arranged in exhaust seat;Two groups of tapered roller bearings are respectively sleeved on the top of male rotor and female rotor, and two pressing plates are respectively fixedly connected on the top of male rotor and female rotor by bolt and are all abutted to tapered roller bearing;Two compression rings are respectively arranged above two groups of tapered roller bearings, and two groups of disc springs are respectively arranged on the top of two compression rings, and its other side is abutted to the bottom of cover plate, wherein gap is additionally provided between the top surface of rotor thread and exhaust seat.By this installation method, female rotor and male rotor can not be mutually rubbed with exhaust seat, and exhaust pressure is also not affected.

Description

Technical Field

[0001] This invention relates to the field of screw compressor technology, and in particular to a method for installing a two-stage screw compressor and a two-stage screw compressor. Background Technology

[0002] A screw compressor consists of a pair of parallel, meshing male and female screws, and is the most widely used type of rotary compressor. It comes in single-screw and twin-screw types, with the term "screw compressor" usually referring to a twin-screw compressor. Screw compressors can also be classified as dry or wet. A dry compressor does not inject liquid into the working chamber, preventing contamination of the compressed gas. A wet compressor injects lubricating oil or other liquids into the working chamber to cool the compressed gas, improve sealing, lubricate the male and female rotors and bearings, and enable self-drive. A high-precision filter then removes oil or other liquid impurities from the compressed air to obtain higher quality compressed gas.

[0003] Since the screw compressor operates through three stages—intake, compression, and exhaust—an axial force is generated during this process. The high-speed rotor constantly exerts this axial force from the high-pressure end to the low-pressure end, causing axial displacement of the rotor towards the low-pressure end. This axial displacement at high speed will cause relative sliding between the journal and the thrust bearing. Because the threaded top surfaces of the female and male rotors are in close contact with the bottom of the exhaust housing, friction between the female and male rotors and the exhaust housing during compressor operation can easily damage the compressor. Furthermore, excessive distance between them can affect the exhaust pressure; therefore, the distance between them needs to be adjusted. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a method for installing a two-stage screw compressor. This method involves adjusting the gap between the female rotor, the male rotor, and the exhaust seat during the installation of the pressure plate. By setting this precise gap, friction between the female rotor and the male rotor and the exhaust seat can be prevented without affecting the overall exhaust pressure.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for installing a two-stage screw compressor, the compressor comprising a male rotor, a female rotor, an exhaust seat, a cover plate, and a pressure plate, wherein the bottom end of the exhaust seat is provided with a first rotor hole and a second rotor hole, and the upper ends of the first rotor hole and the second rotor hole are respectively provided with bearing mounting ports; the method includes the following steps:

[0007] S1. Insert the female rotor's thread into the male rotor's thread gap, and insert the male rotor and female rotor into the first rotor hole and the second rotor hole respectively. Install the bearing assembly at the upper end of the male rotor and female rotor in the bearing mounting port.

[0008] S2. Set several pads of the same height on the bottom of the exhaust seat, and then fix the pressure plate to the top of the female rotor and the male rotor with bolts, so that the plane D of the female rotor and the plane G of the male rotor fit into the bottom surface of the exhaust seat, where plane D is the top of the threaded part of the female rotor and plane G is the top of the threaded part of the male rotor.

[0009] S3. Measure the actual gap between the plane D of the female rotor and the plane G of the male rotor and the bottom of the exhaust seat to obtain the deviation between the gap and the predetermined value.

[0010] S4. Remove the pressure plates installed on the top of the male and female rotors. When the actual gap is greater than the predetermined value, cut the bottom of the pressure plate and push the male and female rotors towards the exhaust seat so that the gap between the plane D of the female rotor and the plane G of the male rotor and the bottom of the exhaust seat reaches the predetermined value. When the actual gap is less than the predetermined value, tap the top surface of the female rotor and the top surface of the male rotor so that the gap between the plane D of the female rotor and the plane G of the male rotor and the bottom of the exhaust seat reaches the predetermined value. Then install the pressure plates on the top of the male and female rotors.

[0011] Preferably, the bearing assembly uses tapered roller bearings.

[0012] Preferably, the tapered roller bearing assembly is composed of two tapered roller bearings stacked together, with the tips of the two tapered roller bearings facing the male rotor or the female rotor.

[0013] As a preferred embodiment, S5, a pressure ring is provided on the tapered roller bearing assembly, and a disc spring is provided at the upper end of the pressure ring. By measuring the height of the disc spring and the height of the top of the exhaust seat, it is ensured that the height of the disc spring is higher than the height of the top of the exhaust seat.

[0014] S6. Place a cover plate on top of the exhaust seat and tighten it with bolts.

[0015] Preferably, in step S1, the bearing assembly is installed at the upper ends of the male and female rotors by heating.

[0016] Preferably, in step S4, the bottom end of the pressure plate is machined, and two parts, a first ring and a second ring, are machined. The first ring abuts against the inner ring of the tapered roller bearing assembly, and the outer diameter of the second ring abuts against the inner ring of the tapered roller bearing assembly.

[0017] Preferably, the method further includes: providing an oil tank groove on the side of the exhaust seat that abuts against the tapered roller bearing assembly, and providing an oil passage communicating with the oil tank groove on the tapered roller bearing assembly.

[0018] Preferably, the method further includes: providing an annular groove and an oil hole on the pressure ring, wherein the annular groove is provided on the outer annular surface of the middle part of the pressure ring, and the oil hole is provided laterally in the middle part of the pressure ring and communicates with the annular groove.

[0019] Preferably, the size of the gap 33 is in the range of 0.03mm-0.17mm.

[0020] Furthermore, a two-stage screw compressor is characterized in that the compressor is equipped with a two-stage screw using the method described in any one of claims 1-9.

[0021] In summary, the advantages of this invention are:

[0022] This method involves adjusting the gap between the female rotor, male rotor, and exhaust seat when installing the pressure plate. The gap size ranges from 0.03mm to 0.17mm. By setting this precise gap, friction between the female rotor and male rotor and the exhaust seat can be prevented without affecting the overall exhaust pressure. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a two-stage screw compressor;

[0024] Figure 2 This is a cross-sectional schematic diagram of the compressor rotor when it is attached to the exhaust seat.

[0025] Figure 3 A cross-sectional schematic diagram showing the gap between the compressor rotor and the exhaust seat;

[0026] Figure 4 This is a schematic diagram of the pressure plate structure;

[0027] Figure 5 This is a schematic diagram of the pressure ring structure;

[0028] Figure 6 This is a schematic diagram of the structure of a tapered roller bearing assembly;

[0029] Figure 7 This is a schematic cross-sectional view of the area through which the oil flows.

[0030] Reference numerals: 1. Male rotor; 2. Female rotor; 3. Exhaust seat; 4. Cover plate; 5. Pressure plate; 6. Tapered roller bearing assembly; 7. Pressure ring; 8. Disc spring; 9. Pad block; 31. First rotor hole; 32. Second rotor hole; 33. Clearance; 34. Oil tank groove; 51. First ring; 52. Second ring; 63. Oil passage; 71. Ring groove; 72. Oil hole. Detailed Implementation

[0031] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0032] like Figures 1 to 7As shown, a method for installing a two-stage screw compressor is disclosed. The compressor includes a male rotor 1, a female rotor 2, an exhaust seat 3, and a cover plate 4. The bottom end of the exhaust seat 3 is provided with a first rotor hole 31 and a second rotor hole 32. The upper ends of the first rotor hole 31 and the second rotor hole 32 are respectively provided with bearing mounting ports. The male rotor 1 and the female rotor 2 are respectively inserted into the first rotor hole 31 and the second rotor hole 32. The upper ends of the male rotor 1 and the female rotor 2 are located inside the bearing mounting ports. The cover plate 4 is fixedly installed on the upper end of the exhaust seat 3 to close the two bearing mounting ports. Tapered roller bearing assemblies 6 are respectively provided on the male rotor 1 and the female rotor 2 and connected to the side walls of the bearing mounting ports. Pressure plates 5 are respectively provided above the upper ends of the male rotor 1 and the female rotor 2. The bottom of the outer ring of the pressure plate 5 abuts against the inner ring of the tapered roller bearing assembly 6. A pressure ring 7 is provided on the upper end of the outer ring of the tapered roller bearing assembly 6. An elastic element is provided on the upper end of the pressure ring 7. The elastic element is pre-compressed and disposed between the pressure ring 7 and the cover plate 4. The tapered roller bearing assembly 6 is composed of two tapered roller bearings stacked together, with the tips of the two tapered roller bearings facing either the male rotor 1 or the female rotor 2. The elastic element is a disc spring 8, with the bottom of its outer ring abutting the upper end of the pressure ring 7 and the upper part of its inner ring abutting the cover plate 4. The exhaust seat 3 has an oil tank groove 34 on the side abutting the tapered roller bearing assembly 6, and an oil passage 63 communicating with the oil tank groove 34 is provided on the tapered roller bearing assembly 6. The pressure ring 7 has an annular groove 71 and an oil hole 72. The annular groove 71 is located on the outer annular surface of the middle part of the pressure ring 7, and the oil hole 72 is laterally located in the middle of the pressure ring 7 and communicates with the annular groove 71. The pressure plate 5 includes a first ring portion 51 and a second ring portion 52. The second ring portion 52 is located at the bottom middle of the first ring portion 51, the first ring portion 51 abutting the top surface of the inner ring of the tapered roller bearing assembly 6, and the second ring portion 52 is located at the top of the female rotor 2 and the male rotor 1. The size of the gap 33 ranges from 0.03mm to 0.17mm.

[0033] like Figure 2 As shown, when installing the entire screw, the female rotor 2, male rotor 1, and exhaust seat 3 are all vertically downward. Since the shape of the male rotor 1 is larger than that of the female rotor 2, that is, the diameter of the hole in the first rotor hole 31 is larger than the diameter of the hole in the second rotor hole 32, it is convenient to insert the male rotor 1 into the first rotor hole 31 and the female rotor 2 into the second rotor hole 32, and the threads of the male rotor 1 and the female rotor 2 mesh.

[0034] like Figure 2 , Figure 3 and Figure 6As shown, two tapered roller bearings stacked one on top of the other form a tapered roller bearing assembly 6. The upper tapered roller bearing is the first bearing section 61, and the lower tapered roller bearing is the second bearing section 62. When the female rotor 2 and the male rotor 1 are inserted into the exhaust seat 3, the tapered roller bearing assembly 6 is first heated. After heating, it is installed on the top shaft ends of the male rotor 1 and the female rotor 2. The first bearing section 61 and the second bearing section 62 are connected in a face-to-face series configuration to maximize the offsetting of the axial force of the load. In the tapered roller bearing assembly 6 located at the top of the male rotor 1, the cone tips of the tapered rollers in the first bearing section 61 and the second bearing section 62 both face the male rotor 1; in the tapered roller bearing assembly 6 located at the top of the female rotor 2, the cone tips of the tapered rollers in the first bearing section 61 and the second bearing section 62 both face the female rotor 2. The tapered roller bearing assembly 6 consists of two bearing sections, and the tapered rollers inside are all arranged at an angle. This design can effectively reduce axial forces in both directions and better protect the bearing.

[0035] like Figure 2 , Figure 3 and Figure 6 As shown, after the tapered roller bearing assembly 6 is fitted onto the tops of the female rotor 2 and the male rotor 1, the pressure plate 5 is fixedly connected to the tops of the female rotor 2 and the male rotor 1 by bolts and abuts against the tapered roller bearing assembly 6. At this time, the plane D of the female rotor 2 and the plane G of the male rotor 1 are in contact with the bottom surface of the exhaust seat 3. Since there is no gap 33 here, it will directly affect the exhaust pressure. First, the actual gap 33 between the plane D of the female rotor 2, the plane G of the male rotor 1, and the bottom surface of the exhaust seat 3 is measured using a feeler gauge. If the actual gap 33 between the plane D of the female rotor 2, the plane G of the male rotor 1, and the bottom surface of the exhaust seat 3 is too small, a copper rod can be used to tap the top surface of the female rotor 2 or the top surface of the male rotor 1 to cause the female rotor 2 and the male rotor 1 to move axially under external force, thereby enlarging the gap 33 between the plane D of the female rotor 2, the plane G of the male rotor 1, and the bottom surface of the exhaust seat 3, so that the gap between the plane D of the female rotor 2 and the plane G of the male rotor and the bottom of the exhaust seat reaches the predetermined value. If the actual gap 33 between the plane D of the female rotor 2, the plane G of the male rotor 1, and the bottom surface of the exhaust seat 3 is too large, the bottom end of the pressure plate is cut and the male rotor and female rotor are pushed towards the exhaust seat to make the gap between the plane D of the female rotor and the plane G of the male rotor and the bottom of the exhaust seat reach the predetermined value. The size of the gap 33 is mainly selected from 0.03mm to 0.17mm depending on the specific situation. At this point, by adjusting the first ring 51 and the second ring 52 of the pressure plate 5, the female rotor 2 and the male rotor 1 are fixed here. The bottom end of the second ring 52 abuts against the top of the female rotor 2 and the male rotor 1, and its outer diameter abuts against the tapered roller bearing assembly 6. The bottom end of the first ring 51 abuts against the tapered roller bearing assembly 6.

[0036] like Figure 2 and Figure 3 As shown, two or more pads 9 of the same height are set on the bottom of the exhaust seat 3, which can facilitate the measurement of the actual gap 33 by the feeler gauge and the subsequent adjustment of the gap 33; it can also play a supporting role during installation.

[0037] When the tapered roller bearing assembly 6 is subjected to the force transmitted from the female rotor 2 and the male rotor 1, a backward axial force is generated. The force is transmitted to the pressure ring 7 at its top and then to the disc spring 8. The disc spring 8 in this device has a strong rebound characteristic. Since the height of the disc spring 8 is higher than the height of the top of the exhaust seat 3, the exhaust seat 3 restricts the preload distance of the disc spring 8 so that it can rebound the axial force. When the axial force is forward, the tapered roller bearing assembly 6 is connected in series and face to face to directly provide axial load. The bottom of the second ring 52 of the pressure plate 5 of the adjustment clearance 33 is close to the inner ring size on the back of the bearing.

[0038] like Figure 2 , Figure 3 and Figure 7 As shown, an oil tank groove 34 is provided on the side of the exhaust seat 3 that abuts against the tapered roller bearing assembly 6, preventing high temperatures in that section due to lack of oil when the equipment is started. This facilitates oil storage and lubrication of the entire device. An oil passage 63 connecting the first bearing section 61 and the second bearing section 62 is provided on the tapered roller bearing assembly 6. An annular groove 71 and an oil hole 72 are provided on the pressure ring 7. The annular groove 71 is located on the outer annular surface of the middle part of the pressure ring 7, and the oil hole 72 is laterally located in the middle of the pressure ring 7 and communicates with the annular groove 71. During operation, oil flows from the oil tank groove 34 backward into the oil passage 63 in the tapered roller bearing assembly 6 to lubricate the tapered rollers, and then flows into the pressure ring 7. The oil flows into the annular groove 71 through the oil hole 72. Excess oil is carried out of the device during operation. The face-to-face arrangement of the first bearing section 61 and the second bearing section 62 ensures proper pairing without oil gaps. However, the remaining oil clearance is only present on the roller side slope. When the bearing working oil clearance is too large, the bearing's load capacity cannot be fully utilized. For bearings operating at low speeds and subjected to vibration, zero-clearance installation or preload installation should be adopted; the purpose is to ensure good contact between the rollers and raceways of the crossed tapered roller bearing assembly 6, uniform load distribution, and to prevent damage to the rollers and raceways from vibration and impact.

[0039] There are two methods for controlling the oil gap on the side slope: ① Subtract the total oil gap of the side slope of the first bearing part 61 and the second bearing part 62 from the gap 33 of the exhaust end face; ② Use the preload of the disc spring 8 to offset part of the oil gap. To ensure the bearing performs optimally, the appropriate preload needs to be correctly adjusted. Excessive preload will lead to increased wear on the bearing rollers and the inner and outer rings of the bearing, as well as an increase in operating temperature, which will shorten the bearing's lifespan.

[0040] like Figure 1As shown, the cover plate 4 is fixedly connected to the top of the exhaust seat 3 by bolts to prevent the pressure plate 5, tapered roller bearing assembly 6, pressure ring 7 and disc spring 8 inside from detaching from the exhaust seat 3 during the movement of the device, thus ensuring the overall stability.

[0041] The installation method is as follows:

[0042] S1. Insert the thread of the female rotor 2 into the thread gap of the male rotor 1, and insert the male rotor 1 and the female rotor 2 into the first rotor hole 31 and the second rotor hole 32 respectively. Install the heated tapered roller bearing assembly at the upper end of the male rotor 1 and the female rotor 2 in the bearing mounting port. The tapered roller bearing assembly 6 is composed of two tapered roller bearings stacked together, and the cone tips of the two tapered roller bearings are facing the male rotor 1 or the female rotor 2.

[0043] S2. Set several pads 9 of the same height on the bottom of the exhaust seat 3, and then fix the pressure plate 5 to the top of the female rotor 2 and the male rotor 1 with bolts, so that the plane D of the female rotor 2 and the plane G of the male rotor 1 fit against the bottom surface of the exhaust seat 3, where the plane D is the top of the threaded part of the female rotor 2 and the plane G is the top of the threaded part of the male rotor 1.

[0044] S3. Measure the actual gap 33 between the plane D of the female rotor 2 and the plane G of the male rotor 1 and the bottom end of the exhaust seat 3, and obtain the deviation of the gap 33 from the predetermined value.

[0045] S4. Remove the pressure plate 5 installed on the top of the male rotor 1 and female rotor 2. First, process the bottom end of the pressure plate 5 to form two parts: a first ring 51 and a second ring 52. Make the first ring 51 abut against the inner ring of the tapered roller bearing assembly 6, and make the outer diameter of the second ring 52 abut against the inner ring of the tapered roller bearing assembly 6. When the actual gap 33 is greater than the predetermined value, cut off part of the second ring 52 of the pressure plate 5 and push the male rotor 1 and female rotor 2 towards the exhaust seat 3 so that the gap 33 between the plane D of the female rotor 2 and the plane G of the male rotor 1 and the bottom end of the exhaust seat 3 reaches the predetermined value. When the actual gap 33 is less than the predetermined value, tap the top surface of the female rotor 2 and the top surface of the male rotor 1 so that the gap 33 between the plane D of the female rotor 2 and the plane G of the male rotor 1 and the bottom end of the exhaust seat 3 reaches the predetermined value. Then install the pressure plate 5 on the top of the male and female rotors.

[0046] S5. Set a pressure ring 7 on the tapered roller bearing assembly 6, and set a disc spring 8 at the upper end of the pressure ring 7. By measuring the height of the disc spring 8 and the height of the top of the exhaust seat 3, ensure that the height of the disc spring 8 is higher than the height of the top of the exhaust seat 3.

[0047] S6. Place the cover plate 4 on top of the exhaust seat 3 and tighten it with bolts.

[0048] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A method for installing a two-stage screw compressor, the compressor comprising a male rotor (1), a female rotor (2), an exhaust seat (3), a cover plate (4), and a pressure plate (5), wherein the exhaust seat (3) has a first rotor hole (31) and a second rotor hole (32) at its bottom end, and the upper ends of the first rotor hole (31) and the second rotor hole (32) are respectively provided with bearing mounting ports; characterized in that, The method includes the following steps: S1. Insert the thread of the female rotor (2) into the thread gap of the male rotor (1), and insert the male rotor (1) and the female rotor (2) into the first rotor hole (31) and the second rotor hole (32) respectively. Install the bearing assembly at the upper end of the male rotor (1) and the female rotor (2) in the bearing mounting port. The bearing assembly adopts a tapered roller bearing assembly (6). The tapered roller bearing assembly (6) is composed of two tapered roller bearings stacked together. The cone tips of the two tapered roller bearings are facing the male rotor (1) or the female rotor (2). S2. Set several pads (9) of the same height on the bottom of the exhaust seat (3), and then fix the pressure plate (5) to the top of the female rotor (2) and the male rotor (1) with bolts, so that the plane D of the female rotor (2) and the plane G of the male rotor (1) fit against the bottom surface of the exhaust seat (3), where the plane D is the top of the threaded part of the female rotor (2) and the plane G is the top of the threaded part of the male rotor (1); S3. Measure the actual gap (33) between the plane D of the female rotor (2) and the plane G of the male rotor (1) and the bottom end of the exhaust seat (3) to obtain the deviation of the gap (33) from the predetermined value. S4. Remove the pressure plate (5) set on the top of the male rotor (1) and female rotor (2). When the actual gap (33) is greater than the predetermined value, cut the bottom of the pressure plate (5) and push the male rotor (1) and female rotor (2) towards the exhaust seat (3) so that the gap (33) between the plane D of the female rotor (2) and the plane G of the male rotor (1) and the bottom of the exhaust seat (3) reaches the predetermined value. When the actual gap (33) is less than the predetermined value, tap the top surface of the female rotor (2) and the male rotor (1). The top surface of the male rotor (2) and the plane D of the female rotor (2) and the plane G of the male rotor (1) are made to achieve a predetermined gap (33) with the bottom end of the exhaust seat (3); then the pressure plate (5) is installed on the top of the male and female rotors; the bottom end of the pressure plate (5) is machined, and two parts, the first ring (51) and the second ring (52), are machined, and the first ring (51) abuts against the inner ring of the tapered roller bearing assembly (6), and the outer diameter of the second ring (52) abuts against the inner ring of the tapered roller bearing assembly (6); S5. A pressure ring (7) is set on the tapered roller bearing assembly (6), and a disc spring (8) is set on the upper end of the pressure ring (7). By measuring the height of the disc spring (8) and the height of the top of the exhaust seat (3), it is ensured that the height of the disc spring (8) is higher than the height of the top of the exhaust seat (3). An annular groove (71) and an oil hole (72) are set on the pressure ring (7). The annular groove (71) is set on the outer annular surface in the middle of the pressure ring (7), and the oil hole (72) is set laterally in the middle of the pressure ring (7) and is connected to the annular groove (71). S6. Place a cover plate (4) on top of the exhaust seat (3) and tighten it with bolts.

2. The method according to claim 1, characterized in that, In step S1, the bearing assembly is installed at the upper ends of the male rotor (1) and female rotor (2) by heating.

3. The method according to claim 1, characterized in that, The method also includes: An oil tank groove (34) is provided on one side of the exhaust seat (3) that abuts against the tapered roller bearing assembly (6), and an oil passage (63) communicating with the oil tank groove (34) is provided on the tapered roller bearing assembly (6).

4. The method according to claim 1, characterized in that, The size of the gap (33) ranges from 0.03mm to 0.17mm.

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