A screw axial flow hybrid pump adopting a composite support method

Abstract

The present invention provides a screw axial flow mixed transport pump adopting a composite support mode, which includes a pump casing with a round inner and square outer shape, an impeller and a shaft. One end of the shaft penetrates into the interior of the pump casing. An inlet support pipe and an outlet support pipe are respectively installed at both axial ends of the pump casing. A radially fixed inlet support is installed between one axial end of the pump casing and the inlet support pipe, and a radially fixed outlet support is installed between the other axial end of the pump casing and the outlet support pipe. The inlet support and the outlet support respectively support both ends of the shaft. Bearing cavities are respectively arranged inside the inlet support and the outlet support. An inlet guide vane is installed at one end of the inlet support. A first through hole communicating with the bearing cavity of the inlet support is arranged on the inlet guide vane for introducing the fluid at the inlet into the bearing cavity as a coolant. The present invention can ensure the stability during the operation of the mixed transport pump and reduce the load borne by the pump body.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluid machinery engineering, and particularly relates to a screw axial flow hybrid pump adopting a composite support method. Background Art

[0002] With the progress and development of human society, the demand for energy is increasing continuously, and the development of offshore oil and gas fields is in an upward stage. The products of offshore oil fields are multiphase mixtures containing oil, gas, water and various impurities, and their gas-liquid ratio exceeds the normal working range of ordinary pumps or compressors. The screw axial flow hybrid pump can directly transport multiphase media, and its direct transportation method simplifies the production process of chemical enterprises and reduces the infrastructure cost.

[0003] The screw axial flow multiphase hybrid pump has the performance characteristics of both centrifugal pumps and axial flow compressors in terms of type, has a wide applicable gas content range and a long service life. The screw axial flow gas-liquid hybrid pump is a series-type multistage pump, and each compression stage includes an impeller and a diffuser. The medium obtains kinetic energy under the rotation of the impeller and then enters the diffuser stage. Through the pressure increasing effect of the diffuser, the kinetic energy of the transported medium is converted into pressure energy, ensuring the normal operation of the pump.

[0004] Both the front and rear supports of traditional screw axial flow hybrid pumps adopt rolling bearings. Rolling bearings require oil lubrication and a corresponding bearing housing is set, with a complex structure. Moreover, the inner cavity of the rolling bearing adopts a sealing method, which does not solve the problem of heat generation due to friction between the bearing and the shaft. At the same time, the sealing wear causes the bearing to come into contact with the medium and is prone to rusting, reducing the service life of the hybrid pump. The traditional cast iron material support requires the shaft to be thickened to ensure strength due to its excessive weight, increasing the weight of the pump body. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention provides a screw axial flow hybrid pump adopting a composite support method. The outer shell of the rotating part can be made of plexiglass, making the visualization during the experiment clearer and facilitating the observation of the gas-liquid mixing condition at the inlet and outlet and the hydraulic condition at the impeller diffuser. The adjacent structures of the overall hybrid pump are convenient for disassembly and replacement. The axial force is balanced by the front and rear sliding bearings and rolling bearings to ensure the stability of the screw axial flow hybrid pump during operation. O-rings are arranged between adjacent pump casings to ensure the sealing performance of the hybrid pump during operation. The radial center of the inlet inducer is perforated through to facilitate the fluid to enter the gap between the sliding bearing and the shaft sleeve, playing a role in water lubrication. A hole is perforated through the lower end of the outlet support to relieve the internal space pressure change caused by the wear of the mechanical seal inside the outlet support and cool the rolling bearing to avoid cavitation.

[0006] The present invention achieves the above technical objectives through the following technical means.

[0007] A screw axial-flow hybrid pump adopting a composite support method, comprising a pump casing with a square outside and a circular inside, an impeller and a shaft. One end of the shaft penetrates into the inside of the pump casing, and a number of stages of impellers are installed on the shaft. A guide vane installed on the pump casing is provided between each stage of impellers. Axial inlet and outlet support pipes are respectively installed at both ends of the pump casing. The inlet support pipe is connected to the inlet pipe, and the outlet support pipe is connected to the outlet pipe. A radially fixed inlet support is installed between one axial end of the pump casing and the inlet support pipe, and a radially fixed outlet support is installed between the other axial end of the pump casing and the outlet support pipe. The inlet support and the outlet support respectively support both ends of the shaft. Bearing cavities are respectively arranged inside the inlet support and the outlet support. An inlet flow guide is installed at one end of the inlet support. A first through hole communicating with the bearing cavity of the inlet support is provided on the inlet flow guide for introducing the fluid at the inlet into the bearing cavity as a coolant, saving the bearing housing required for setting the bearing.

[0008] Further, a sliding bearing is installed in the bearing cavity of the inlet support. A thrust disc is coaxially arranged near the outlet end of the sliding bearing. A shaft sleeve installed on the shaft is arranged on the radially inner side of the sliding bearing 5. The shaft sleeve near the outlet section contacts the thrust disc.

[0009] Further, a gap of 0.2 - 0.5 mm is provided between the thrust disc and the sliding bearing. The coolant passes through the gap between the sliding bearing and the shaft sleeve and the gap between the thrust disc and the sliding bearing for cooling and lubricating the sliding bearing and the thrust disc.

[0010] Further, a rolling bearing is installed in the bearing cavity of the outlet support. A sealing cavity is provided on one side of the bearing cavity of the outlet support. A sealing component is installed in the sealing cavity. A second through hole is provided at the bottom of the sealing cavity. The second through hole communicates the sealing cavity of the outlet support with the inner flow path of the casing, ensuring that the medium entering the cavity of the outlet support from the sealing component is discharged smoothly, avoiding dead water in the internal area, and at the same time cooling the rolling bearing.

[0011] Further, an outlet flow guide is installed in the outlet direction of the outlet support. An axial gap of 0.2 - 0.3 mm is provided between the rolling bearing near the inlet side and the bearing cavity of the outlet support to balance the axial force during the operation of the pump and avoid the axial movement of the rotating part during operation.

[0012] Further, a tip clearance of no more than 0.5 mm is provided between each stage of impeller and the pump casing. The cross-section of each stage of impeller is set as an "I" shape, saving material usage and reducing the burden on the shaft.

[0013] Further, the radially inner part of the guide vane is a hollow structure, saving material usage and reducing the burden on the shaft.

[0014] Further, the pump casing is made of transparent organic material.

[0015] The beneficial effects of the present invention are as follows:

[0016] For the screw axial flow hybrid pump adopting the composite support method of the present invention, the outer shell of the rotating part can be made of plexiglass, making the visualization during the experiment clearer and facilitating the observation of the gas-liquid mixing condition at the inlet and outlet and the hydraulic condition at the impeller guide vane; the adjacent structures of the overall hybrid pump are convenient for disassembly and replacement; the axial force is balanced by the front and rear sliding bearings and rolling bearings to ensure the stability of the screw axial flow hybrid pump during operation; O-rings are arranged between adjacent pump casings to ensure the sealing performance of the hybrid pump during operation; the radial center of the inlet inducer is perforated through, facilitating the fluid to enter the gap between the sliding bearing and the shaft sleeve, playing a role in water lubrication. A hole is provided through the lower end of the outlet support to relieve the internal space pressure change caused by the wear of the mechanical seal inside the outlet support and cool the rolling bearing to avoid cavitation. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. The drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained obviously without creative efforts based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of the screw axial flow hybrid pump adopting the composite support method of the present invention.

[0019] Figure 2 It is a schematic diagram of the front support structure in the screw axial flow hybrid pump adopting the composite support method of the present invention.

[0020] Figure 3 It is a schematic diagram of the rear support structure in the screw axial flow hybrid pump adopting the composite support method of the present invention.

[0021] In the figure:

[0022] 1 - inlet pipe; 2 - inlet inducer; 3 - inlet support pipe; 4 - inlet support; 5 - sliding bearing; 6 - thrust disk; 7 - last-stage impeller; 8 - last-stage guide vane; 9 - rotary seal; 10 - rolling bearing; 11 - outlet inducer; 12 - outlet pipe; 13 - shaft; 14 - pull rod; 15 - outlet support pipe; 16 - outlet support; 17 - pump casing; 18 - second shaft sleeve; 19 - first-stage guide vane; 20 - first-stage impeller; 21 - flange; 22 - shaft sleeve; 23 - O-ring. Detailed Embodiments

[0023] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0025] In the present invention, unless otherwise clearly specified and defined, the terms "mount", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] As Figure 1 shown, the screw axial flow hybrid pump adopting a composite support method according to the present invention includes a pump casing 17 with a round inner and square outer shape, an impeller and a shaft 13. The pump casing 17 can be axially spliced by multiple sections of pump casings, and an O-ring 23 is provided between adjacent pump casings; both axial ends of the pump casing 17 are respectively installed with an inlet support pipe 3 and an outlet support pipe 15. The inlet support pipe 3 is connected to the inlet pipe 1, and the outlet support pipe 15 is connected to the outlet pipe 12; flanges 21 are respectively provided between the pump casing 17 and the inlet support pipe 3 and between the pump casing 17 and the outlet support pipe 15 by mating with a spigot. One end of the inlet pipe 1 and one end of the outlet pipe 12 are respectively installed with flanges 21, and several flanges 21 are connected by a tie rod 14 to seal the connection of the pump casing 17, the inlet support pipe 3, the outlet support pipe 15, the inlet pipe 1 and the outlet pipe 12.

[0027] A radially fixed inlet support 4 is installed between one axial end of the pump casing 17 and the inlet support pipe 3, and a radially fixed outlet support 16 is installed between the other axial end of the pump casing 17 and the outlet support pipe 15; the inlet support 4 and the outlet support 16 respectively support both ends of the shaft 13; one end of the shaft 13 penetrates into the interior of the pump casing 17, and a number of stages of impellers are installed on the shaft 13, and a guide vane installed on the pump casing 17 is provided between each stage of impellers; bearing cavities are respectively provided inside the inlet support 4 and the outlet support 16.

[0028] As Figure 2 shown, the outer radial edge of the inlet support 4 is clamped and fixed with the flange 21 through the inlet support pipe 3. An inlet flow deflector 2 is arranged on the inlet support 4 close to the inlet side. The inlet flow deflector 2 is coaxially fixed to the inlet support 4 through a pin. The sliding bearing 5 is fixed to the radial inner side of the bearing cavity of the inlet support 4 through a pin. A thrust disc 6 is coaxially arranged at the outlet end of the sliding bearing 5. A shaft sleeve 22 is arranged on the radial inner side of the sliding bearing 5. A nut is arranged at the inlet end of the shaft sleeve 22 for fixation. The shaft sleeve 22 is in contact and fixed with the thrust disc at the outlet section. The first-stage impeller 20 is coaxially in contact and fixed with the thrust disc 6 at the inlet side. A second shaft sleeve 18 is arranged on the outlet side of the first-stage impeller 20. The first-stage impeller 20 and the second shaft sleeve 18 are radially fixed to the shaft 13 through a key and rotate coaxially. The outer edge of the first-stage guide vane is clamped and fixed by the adjacent pump casing 17. Two groups of impeller guide vane shaft sleeves are coaxially arranged in sequence in the outlet direction of the second shaft sleeve 18. The impeller shaft sleeves are coaxially fixed to the shaft 13 through a key. The guide vane is clamped and fixed by the pump casing 17. The last-stage impeller 7 is clamped and fixed by the pump casing 17 and the steel plate 21. O-rings 23 are arranged on the axial contact surfaces of the adjacent pump casings 17.

[0029] One end of the inlet support 4 is provided with an inlet flow deflector 2. The inlet flow deflector 2 is provided with a first through hole communicating with the bearing cavity of the inlet support 4 for introducing the fluid at the inlet into the bearing cavity as a coolant. Part of the medium flows into the gap between the sliding bearing 5 and the shaft sleeve 22, playing a role in cooling and lubrication, avoiding the problem of excessive temperature caused by friction, and at the same time preventing cavitation. There is a gap between the sliding bearing 5 and the shaft sleeve 22, which is conducive to forming a lubricating oil film and ensuring the stability of the operation of the hybrid pump.

[0030] As Figure 3As shown, both ends of the radial outer side of the outlet support 16 are clamped and fixed to the outlet pipe 12 through flanges 21. A sealing cavity is provided on one side of the bearing cavity of the outlet support 16. A rotary seal 9 is arranged near the inlet direction in the sealing cavity of the outlet support 16. The radial inner side of the rotary seal 9 is fixed to the shaft 13. A rolling bearing 10 is arranged near the outlet direction in the bearing cavity inside the outlet support 16. The radial inner side of the rolling bearing 10 is fixed to the shaft 13. The outlet diffuser 11 is coaxially fixed to the outlet side of the outlet support through a pin. A rotary seal is arranged near the inlet direction on the radial inner side of the outlet diffuser 11. A second through hole is provided at the bottom of the sealing cavity. The second through hole communicates the sealing cavity of the outlet support 16 with the inner flow passage of the housing. With the pressure increasing effect of the impeller guide vane, the working medium enters the outlet support 16. Due to the possible wear caused by the friction between the rotation of the shaft 13 and the rotary seal 9, part of the medium enters the oil seal area inside the outlet support 16 radially. A hole is drilled at the lower part of the outlet support 16 to ensure the smooth discharge of the medium, and the bearing cavity where the rolling bearing 10 is installed is cooled to avoid stagnant water in the internal area.

[0031] During operation, the gas-liquid mixture enters the pipeline through the inlet pipe 1 and enters the working area through the inlet diffuser 2. A central hole is provided in the inlet diffuser 2 so that a small part of the medium flows into the inside of the inlet diffuser 2. Due to the initial velocity of the medium, the medium passes through the gap between the sliding bearing 5 and the shaft sleeve 22 and flows into the working area from the gap between the inlet support 4 and the first-stage impeller 20. Most of the medium enters the working area through the inlet support 4, successively passes through the first-stage impeller 20 and the first-stage guide vane 21, and enters the next compression stage. With the rotation of each stage of the impeller, the pressure increases, and finally it flows into the outlet support pipeline 15 through the last-stage guide vane 7.

[0032] The inlet pipe 1, the pump casing 17, the outlet pipe 12 and the guide vanes are all made of plexiglass materials. The mixing situation of the incoming gas-liquid mixture can be observed through the inlet pipe 1. The inlet support 4 ensures the smoothness of the incoming medium, reduces the flow loss, and at the same time supports the inlet support pipeline 3 and the shaft 13, reducing the axial force burden on the shaft. The outlet support 16 supports the outlet support pipeline 15 and the shaft 13, reducing the axial force burden on the shaft.

[0033] There is a 0.5 mm tip clearance between each stage of the impeller and the pump casing, and each stage of the impeller is subjected to material reduction treatment inside radially. The cross-section is set in the shape of "I", saving material usage and reducing the shaft burden. The inside of the guide vane is hollowed out radially, reducing the burden of the pump casing clamping and fixing the guide vane.

[0034] There is a 0.4 mm clearance between the thrust disk 6 and the sliding bearing 5, and there is a 0.3 mm clearance between the rolling bearing 10 and the outlet support near the inlet side. The above design balances the axial force of the pump during operation and avoids the axial movement of the rotating part during operation. In the embodiment, both the impeller and the guide vane are provided with 3 stages.

[0035] It should be understood that although this specification is described in accordance with various embodiments, not every embodiment contains only one independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0036] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent embodiments or changes made without departing from the technical spirit of the present invention should be included within the protection scope of the present invention.

Claims

1. A screw axial flow hybrid pump adopting a composite support method, comprising a pump casing (17), an impeller and a shaft (13), one end of the shaft (13) penetrates into the interior of the pump casing (17), a plurality of stages of impellers are installed on the shaft (13), and a guide vane installed on the pump casing (17) is provided between each stage of impellers; characterized in that, The inlet support pipe (3) and the outlet support pipe (15) are respectively installed at both axial ends of the pump casing (17). The inlet support pipe (3) is connected to the inlet pipe (1), and the outlet support pipe (15) is connected to the outlet pipe (12). A radially fixed inlet support (4) is installed between one axial end of the pump casing (17) and the inlet support pipe (3), and a radially fixed outlet support (16) is installed between the other axial end of the pump casing (17) and the outlet support pipe (15). The inlet support (4) and the outlet support (16) respectively support both ends of the shaft (13). Bearing cavities are respectively provided inside the inlet support (4) and the outlet support (16). One end of the inlet support (4) is installed with an inlet flow guide (2), and the inlet flow guide (2) is provided with a first through hole communicating with the bearing cavity of the inlet support (4) for introducing the fluid at the inlet into the bearing cavity as a coolant. A sealing cavity is provided on one side of the bearing cavity of the outlet support (16), a sealing component is installed in the sealing cavity, a second through hole is provided at the bottom of the sealing cavity, and the second through hole communicates the sealing cavity of the outlet support (16) with the internal flow passage of the casing. A sliding bearing (5) is installed in the bearing cavity of the inlet support (4). A thrust disk (6) is coaxially arranged near the outlet end of the sliding bearing (5). A shaft sleeve (22) installed on the shaft (13) is arranged on the radial inner side of the sliding bearing (5), and the shaft sleeve (22) near the outlet section contacts the thrust disk (6). A gap of 0.2 - 0.5 mm is provided between the thrust disk (6) and the sliding bearing (5). The coolant passes through the gap between the sliding bearing (5) and the shaft sleeve (22) and the gap between the thrust disk (6) and the sliding bearing (5) to cool and lubricate the sliding bearing (5) and the thrust disk (6).

2. The screw axial flow hybrid pump adopting the composite support method according to claim 1, characterized in that, A rolling bearing (10) is installed in the bearing cavity of the outlet support (16).

3. The screw axial flow hybrid pump adopting the composite support method according to claim 2, wherein, An outlet flow guide (11) is installed in the outlet direction of the outlet support (16). An axial gap of 0.2 - 0.3 mm is provided between the rolling bearing (10) near the inlet side and the bearing cavity of the outlet support (16).

4. The screw axial-flow hybrid pump adopting a composite support method according to claim 1, characterized in that, There is a tip clearance of no more than 0.5 mm between several stages of impellers and the pump casing (17) respectively, and the cross-section of each stage of impeller is set as an "I" shape.

5. The screw axial flow hybrid pump adopting the composite support method according to claim 1, wherein, The radial interior of the guide vane is a hollow structure.

6. The screw axial flow hybrid pump adopting the composite support method according to claim 1, characterized in that, The pump casing (17) is made of transparent organic material.

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