Trochoid pump stage and multistage trochoid pump
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- PYATOV IVAN SOLOMONOVICH
- Filing Date
- 2026-01-16
- Publication Date
- 2026-07-30
Smart Images
Figure RU2026000003_30072026_PF_FP_ABST
Abstract
Description
[0001]
[0002] STAGE OF A TROCHOID PUMP AND A MULTISTAGE TROCHOID PUMP
[0003] The group of inventions relates to the field of mechanical engineering, in particular to positive displacement pumps designed for pumping liquids.
[0004] A known multi-stage rotary pump comprises a housing closed by end covers and, located inside the cavity of the housing, at least one shaft mounted on bearing supports, and rotors rigidly mounted on the shaft, separated by radial partitions secured to the housing, with the formation of successive stages of compression of the working medium, made with working chambers and suction and discharge windows, communicated with the inlet and outlet fittings by means of channels, respectively, wherein the discharge window of each stage of compression of the working medium is communicated with the suction window of the adjacent stage, subsequent in the direction of movement of the flow of the working medium.
[0005] The rotors of each pump stage are internally geared, with each inner rotor's tooth fully meshing with the outer rotor. In adjacent compression stages of the working fluid, the outer rotors are offset circumferentially by 180°. The outer rotor is provided with internal teeth, while the inner rotor, rigidly mounted on the shaft, is eccentric relative to the outer rotor and is equipped with external teeth, the number of which is one less than the number of teeth on the outer rotor (according to patent RU55896, IPC F04C 13 / 00, published
[0006] 27.08.06).
[0007] The disadvantage of this pump is that the liquid enters and exits the stages perpendicular to the pump axis, which increases the diameter of the pump and limits its use in the well.
[0008] A well-known multistage trochoidal pump consists of two or more trochoidal stages, including a stator and inner and outer rotors, mounted with internal engagement and the ability to rotate relative to each other. The rotors are mounted on a shaft with circumferential locking and without axial locking. The rotors are mounted eccentrically within the stators in an axial friction bearing. In adjacent stages, the rotors are offset circumferentially by 180°. The shaft is mounted in bearing supports. The stages are separated by a guide vane, which contains one through hole and two blind holes separated by a partition. The hole connects the outlet below the installed stage with the inlet above it.In the stator of the stage, two bypass channels are made, one of which connects the output of the stage with the opening below the installed apparatus, and the other connects the input of the stage with the opening above the installed apparatus (according to patent RU2739932, IPC F04C 11 / 00, F04C 2 / 10, published.
[0009] 29.12.20).
[0010] The disadvantage of this pump is that the difference in pressure at the inlet and outlet of the stage creates a radial force that acts on the rotors and creates a bending moment on the shaft, reducing its service life and increasing stator wear.
[0011] The closest technical solution is a multistage borehole trochoidal pump, which consists of two or more trochoidal stages, including a stator with end caps, one of which contains the inlet and the other the outlet. The inner and outer rotors are mounted with internal engagement and mutual rotation. The rotors are mounted on a shaft with circumferential locking. The rotors are eccentrically mounted within the stators of the stages in an axial friction bearing. In adjacent stages, the rotors are offset circumferentially by 180°. The shaft is mounted in bearing supports. The stages are separated by a guide vane. In the cavities of the outer rotor, radial holes are made, connecting the internal cavities between the outer and inner rotors with the gap between the rotor and the bearing (according to patent RU2775052, IPC F04C 11 / 00, F04C 2 / 10, published 06 / 27 / 22).
[0012] Radial holes in the outer rotor valleys of this pump reduce bending loads on the shaft by equalizing the pressure inside and outside the outer rotor, but they do not solve the problem of wear on the rotor end surfaces. Furthermore, rigidly fastening the inner rotor to the shaft radially, even with slight dimensional deviations, can also lead to bending loads on the shaft, wear, and failure of the rotors.
[0013] The technical result achieved by using the invention consists in increasing the operational reliability and service life of a multi-stage trochoidal pump due to the design solutions employed. The said technical result is achieved in that the stage of the trochoidal pump comprises a stator with a cylindrical cavity with an external rotor with internal teeth located in this cavity; an internal rotor with an opening and external teeth is installed inside the external rotor with an eccentricity and the possibility of mutual rotation, forming working cavities for suction and compression, wherein the number of teeth of the internal rotor is less than the number of teeth of the external rotor and is taken from the series i = 3 / 4...9 / 10, end disks are adjacent to the ends of the stator, one of which has an inlet window, and the other - an outlet window, is distinguished in that the profile of the teeth of the outer rotor is made cylindrical, radial stops are made in the opening of the inner rotor for transmitting torque from the shaft to the inner rotor mounted on the shaft with a radial clearance, and an axial clearance is made between the end disks and the ends of the outer and inner rotors, radial grooves are made on the ends of the outer rotor for supplying liquid compressed between the teeth of the outer and inner rotors as a lubricant into the axial clearance between the end disks and the ends of the outer and inner rotors and a cylindrical cavity between the outer rotor and the stator.
[0014] In addition, the inter-tooth engagement of the rotors can be performed with a lateral clearance in the range from 20 to 100 µm.
[0015] In addition, the inner rotor can be made of steel, and the outer rotor can be combined, the inner part with teeth made of a polymer composite, reinforced on the outside with a steel shell.
[0016] In addition, the stator and end discs can be made of a carbon-containing ceramic-like composite.
[0017] In addition, the end disk with the discharge window can be equipped with a damping elastic ring that contacts the end of the inner rotor, and an antifriction layer of elastomer is applied to the end disk with the entry window on the rotor side, which functions as a thrust bearing.
[0018] In addition, radial holes can be made in the cavities between the teeth of the outer rotor, connecting the internal cavities between the outer and inner rotor with the cylindrical cavity between the outer rotor and the stator.
[0019] In addition, the cavity between the outer rotor teeth and the inner rotor tooth forms a minimum volume corresponding to a compression ratio of 8...10.
[0020] In addition, a hydrophobic coating from the fluoroparaffin family can be applied to the inner surface of the stator and the end discs of the stator.
[0021] The technical result is also achieved in that the multi-stage trochoid pump consists of an input module, a discharge manifold, a shaft mounted in at least two bearing supports, and sequentially installed trochoid stages, wherein the input window of the first stage is connected to the input module, and the discharge window of the last stage with the discharge manifold, the input window of each subsequent stage is connected to the discharge window of the previous stage, characterized in that the trochoid stages are made according to the proposed invention, the internal rotors of each stage are mounted on the shaft with a radial clearance, and grooves are made on the shaft at the location of the installation of the stages, repeating the shape of the radial stops in the holes of the internal rotors and serving to transmit torque to the internal rotors of the stages.
[0022] In addition, the discharge manifold can be connected to the shaft cavity, and a shaft seal with damping properties is installed in front of the first stage inlet window, preventing the flow of liquid from the shaft cavity into the inlet module.
[0023] In addition, each subsequent stage can be rotated 180° along the axis relative to the previous one, with the ejection window of the previous stage oriented toward the entry window of the subsequent stage, and the end disks of the stages are unified with each other.
[0024] In addition, the stages can be made coaxial, with the end disks of the stage being made as two-part components that form an annular cavity with the function of a guide vane, with the inlet window located on one half of the disk and the discharge window on the other half of the disk.
[0025] In addition, the stages can be made coaxial, with the end disk of the previous stage being made as a single unit with the end disk of the next stage, the exit window of the previous stage being connected to the entry window of the next stage by an annular cavity.
[0026] In addition, a filter and / or gas separator can be installed at the inlet.
[0027] In addition, the pump body can be made of silica pipes, such as glass basalt. The proposed group of inventions is explained by the following drawings, which depict:
[0028] Fig. 1 - trochoid steps, longitudinal section;
[0029] Fig. 2 - trochoid step, front view;
[0030] Fig. 3 - inter-tooth engagement of rotors;
[0031] Fig. 4 - inner and outer rotors, axonometry;
[0032] Fig. 5 - shaft with internal rotor, axonometry;
[0033] Fig. 6 - multistage trochoid pump, longitudinal section; Fig. 7 - borehole multistage trochoid pump in a borehole; Trochoid pump stage 1 (Fig. 1) contains stator 2 with cylindrical cavity 3, inside which outer rotor 4 with inner teeth 5 is placed. Inside outer rotor 4, with eccentricity and with the possibility of mutual rotation, inner rotor 6 with hole 7 and outer teeth 8 is installed with the formation of working cavities of suction 9 and compression 10 (Fig. 2). The number of teeth 8 of inner rotor 6 is less than the number of teeth 5 of outer rotor 4 and is taken from the series i = 3 / 4... 9 / 10 depending on the dimensions of the stage. End disks I are adjacent to the ends of the stator 2, one of which has an inlet window 12, and the other has an outlet window 13. In the opening 7 of the inner rotor 6, radial stops 14 are made. Between the end disks 11 and the ends of the outer rotor 4 and the inner rotor 6, an axial gap is made.The end disk 11 with the discharge window 13 is provided with a damping elastic ring 15, which contacts the end of the inner rotor 6, and on the end disk 11 with the entry window 12 on the side of the rotors 4 and 6 an antifriction layer of elastomer 16 is applied, which performs the function of a thrust bearing.
[0034] The profile of the teeth 5 of the outer rotor 4 is made cylindrical with a diameter D. The intertooth engagement of the rotors 4 and 6 is made with a lateral clearance H in the range from 20 to 100 µm (Fig. 3).
[0035] On the ends of the outer rotor 4, radial grooves 17 are made (Fig.
[0036] 4) for supplying liquid compressed between the teeth 5 of the outer rotor 4 and the teeth 8 of the inner rotor 6 as a lubricant into the axial gap between the end disks 11 and the ends of the outer rotor 4 and the inner rotor 6 and the cylindrical cavity 3 between the outer rotor 4 and the stator 2. In the cavities between the teeth 5 of the outer rotor 4, radial holes 18 are made, connecting the working cavities 9 and 10 between the outer rotor 4 and the inner rotor 5 with the cylindrical cavity 3 between the outer rotor 4 and the stator 2.
[0037] The inner rotor 6 is mounted on the shaft 19 (Fig. 5) with a radial clearance. On the shaft 19, at the location where stage 1 is installed, grooves 20 are made that repeat the shape of the radial stops 14 in the opening 7 of the inner rotor 6 and serve to transmit torque from the shaft 19 to the inner rotor 6.
[0038] A multistage trochoid pump (Fig. 6) consists of an inlet module 21 and a discharge manifold 22 connected by a housing 23, a shaft 19 mounted in bearing supports 24, and trochoid stages 1 arranged in series. The inlet window 12 of the first stage is connected to the inlet module 21, and the discharge window 13 of the last stage is connected to the discharge manifold 22. The inlet window 12 of each subsequent stage is connected to the discharge window 13 of the previous stage. This can be realized by rotating each subsequent stage by 180° so that the discharge window 13 of the previous stage coincides with the inlet window 12 of the next stage. In this case, the end disks 11 of the stages can be unified with each other. Or the stages can be arranged coaxially, then the end disks 11 can be composed of two parts or a single whole with the formation of an annular cavity 25, which performs the function of a guide apparatus and connects the discharge window 13 of the previous stage with the entry window 12 of the next stage.The discharge manifold 22 is connected to the shaft cavity formed by the gap between the internal rotors 6 and the shaft 19. In front of the inlet window 12 of the first stage, a shaft seal 26 with damping properties is installed, preventing the flow of liquid from the shaft cavity into the inlet module 21.
[0039] Multistage trochoid pump 27 (Fig. 7) can be used as part of a borehole pump installation consisting, in addition to pump 27, of a submersible electric motor 28, hydraulic protection 29, filter 30, and gas separator 31. The installation is connected to a tubing string (TUB) 32 secured to the wellhead. Power supply to submersible electric motor 28 is provided via cable 33.
[0040] The multistage borehole pump operates as follows. Pump 27, as part of the unit, is lowered into the wellbore on tubing string 32. Power is supplied via cable 33 to electric motor 28, which transmits torque to shaft 19 of pump 27. Inner rotor 6 rotates with shaft 19 and, through engagement with outer rotor 4, transmits rotation to it. As a result, fluid is transferred from inlet port 12 to discharge port 13 of stage 1 and enters through annular cavity 25 into inlet port 12 of the next stage, where the process is repeated. The fluid enters the inlet of the lower pump stage through filter 30, gas separator 31, and inlet module 21. After passing through all stages, the fluid enters tubing string 32 and is pumped to the surface.
[0041] The cylindrical profile of teeth 5 of outer rotor 4 ensures improved contact and reliable sealing with inner rotor 6 during their engagement. A lateral clearance H in the range of 20 to 100 µm in the intertooth engagement reduces wear on the stage without compromising the sealing reliability of the contact area between outer rotor 4 and inner rotor 6, as sealing occurs through linear tooth contact and full contact between the gullet of teeth 8 of inner rotor 6 and tooth 5 of outer rotor 4 is not required. Furthermore, lateral clearance H ensures the relative positioning of rotors 4 and 6, eliminating radial pressure on shaft 19.
[0042] Radial grooves 17 on the ends of the outer rotor 4 allow the pumped fluid, which acts as a lubricant, to be supplied to the lower end of the inner rotor 4 using the compressive energy of the working fluid from the top dead center. This reduces friction and, consequently, wear and heat.
[0043] The installation of a damping elastic ring 15 on end disk I with discharge port 13, which contacts the end of inner rotor 6, prevents fluid from flowing into the stage. The implementation of an elastomer layer 16 on end disk 11 with an entry port reduces mutual wear between rotors 4 and 6 and end disk 11.
[0044] The installation of the inner rotor 6 on the shaft 19 with a radial clearance, which became possible due to the radial stops 14 in the opening 7 of the inner rotor 6 and the grooves 20, repeating the shape of the radial stops 14, on the shaft 19. This made it possible to eliminate the radial load on the shaft 19, arising due to the difference in pressure at the input and output of stage 1. The radial load on the shaft 19 is also reduced by the radial holes 18 in the outer rotor, which ensure pressure equalization in the cavity 3.
[0045] The connection of the discharge window 13 of the last stage of the pumped liquid in the direction of movement with the cavity of the shaft 19 and the installation of the first stage of the shaft seal 26 with damping properties in front of the inlet window 12 makes it possible to eliminate the flow of liquid from the pump outlet to the inlet along the shaft, and, consequently, the clogging of the radial clearance between the inner rotor 6 and the shaft 19.
[0046] The implementation of each subsequent stage, rotated 180° relative to the previous one, with the discharge window 13 of the previous stage oriented towards the inlet window 12 of the subsequent stage, allows for the simplification and unification of the pump design, which will have a positive effect on its reliability and service life.
[0047] Making the stages coaxial allows eliminating multidirectional radial loads on shaft 19, and when making the end disk of the previous stage as a single unit with the end disk of the next stage, it also reduces the flow of liquid at the junction of the end disks.
[0048] The production of the inner rotor 6 from steel, the outer rotor 4 as a combined one, when the inner part is made of a polymer composite, reinforced on the outside by a steel shell, as well as the production of the stator 2 and end disks 11 from a carbon-containing ceramic-like composite makes it possible to increase the strength, and, consequently, the reliability of the stage.
[0049] Application of a hydrophobic coating from the fluoroparaffin family reduces various deposits (salts, ASPO, etc.) on the surface of stage parts.
[0050] The construction of the pump body from silica pipes, such as glass basalt, ensures high strength and a relatively low weight of the pump.
[0051] The use of a filter and gas separator in a trochoid pump system improves reliability, as the liquid entering the pump is cleaned of mechanical impurities and separated from any gas that may be dissolved in the liquid.
[0052] Thus, the technical solutions proposed in the invention increase the operational reliability and service life of the multi-stage trochoid pump and contribute to the achievement of the technical result.
Claims
CLAUSES OF THE INVENTION 1. A stage of a trochoid pump containing a stator with a cylindrical cavity with an external rotor with internal teeth placed in this cavity, inside the external rotor with eccentricity and with the possibility of mutual rotation, an internal rotor with an opening and external teeth is installed with the formation of working cavities for suction and compression, wherein the number of teeth of the internal rotor is less than the number of teeth of the external rotor and is taken from the series i = 3 / 4...9 / 10, end disks are adjacent to the ends of the stator, one of which has an inlet window, and the other - an outlet window, characterized in that the profile of the teeth of the outer rotor is made cylindrical, radial stops are made in the opening of the inner rotor for transmitting torque from the shaft to the inner rotor mounted on the shaft with a radial clearance, and an axial clearance is made between the end disks and the ends of the outer and inner rotors, radial grooves are made on the ends of the outer rotor for supplying liquid compressed between the teeth of the outer and inner rotors as a lubricant into the axial clearance between the end disks and the ends of the outer and inner rotors and a cylindrical cavity between the outer rotor and the stator.
2. A stage according to paragraph 1, characterized in that the intertooth engagement of the rotors is made with a lateral clearance in the range from 20 to 100 µm.
3. A stage according to paragraph 1, characterized in that the inner rotor is made of steel, and the outer rotor is combined, the inner part with teeth is made of a polymer composite, reinforced on the outside with a steel shell.
4. The stage according to item 1, characterized in that the stator and end disks are made of a carbon-containing ceramic-like composite.
5. A stage according to claim 1, characterized in that the end disk with the discharge window is provided with a damping elastic ring that contacts the end of the inner rotor, and an antifriction layer of elastomer is applied to the end disk with the entry window on the rotor side, which performs the function of a thrust bearing.
6. A stage according to claim 1, characterized in that radial openings are made in the cavities between the teeth of the outer rotor, connecting the working cavities between the outer and inner rotor with the cylindrical cavity between the outer rotor and the stator.
7. The stage according to paragraph 1, characterized in that the cavity between the teeth of the outer rotor and the tooth of the inner rotor forms a minimum volume corresponding to a compression ratio of 8...10.
8. The stage according to paragraph 1, characterized in that a hydrophobic coating from the fluoroparaffin family is applied to the inner surface of the stator and the end disks of the stator.
9. A multi-stage trochoid pump consisting of an input module and a discharge manifold connected by a housing, a shaft mounted in at least two bearing supports, and trochoid stages installed in series, wherein the input window of the first stage is connected to the input module, and the discharge window of the last stage is connected to the discharge manifold, the input window of each subsequent stage is connected to the discharge window of the previous stage, characterized in that the trochoid stages are made according to paragraphs 1-6, the internal rotors of each stage are mounted on the shaft with a radial clearance, and grooves are made on the shaft at the location where the stages are installed, repeating the shape of the radial stops in the holes of the internal rotors and serving to transmit torque to the internal rotors of the stages.
10. The pump according to paragraph 9, characterized in that the discharge manifold is connected to the shaft cavity, and a shaft seal with damping properties is installed in front of the first stage inlet window, preventing the flow of liquid from the shaft cavity into the inlet module.
11. The pump according to paragraph 9, characterized in that each subsequent stage is rotated 180° along the axis relative to the previous one, while the discharge window of the previous stage is oriented toward the inlet window of the next stage.
12. A pump according to item I, characterized in that the end disks of the stages are unified with each other.
13. A pump according to paragraph 9, characterized in that the stages are made coaxial, and the end disks of the stage are made as two-part components that form an annular cavity with the function of a guide vane, with the inlet window located on one half of the disk and the discharge window on the other half of the disk.
14. The pump according to paragraph 9, characterized in that the stages are made coaxial, and the end disk of the previous stage is made as a single unit with the end disk of the next stage, the outlet window of the previous stage is connected to the inlet window of the next stage by an annular cavity.
15. The pump according to paragraph 9, characterized in that a filter and / or gas separator device is installed at the inlet.
16. The pump according to paragraph 9, characterized in that the pump body is made of silica pipes, for example, glass basalt.