WO2007083872A1

WO2007083872A1 - Rotor structure of rotary positive displacement pump

Info

Publication number: WO2007083872A1
Application number: PCT/KR2006/003821
Authority: WO
Inventors: Sung Wang RO
Original assignee: Jinmyung21 Co., Ltd.
Priority date: 2006-01-18
Filing date: 2006-09-26
Publication date: 2007-07-26
Also published as: KR100593208B1

Abstract

The present invention relates to a rotor structure of a rotary positive displacement pump including a main rotor (10) and a subsidiary rotor (20), each of which has a plurality of compressing protrusions (12), (24). In the rotor structure of the present invention, a plurality of seating grooves (40) is formed in the surfaces of the compressing protrusions of the main rotor and the subsidiary rotor, and an elastic protrusion member (16), (22), which has a '(I)' shape, is seated into each of the seating grooves. Furthermore, rubber layers (42) are applied on respective circumferential outer surfaces of the main rotor and the subsidiary rotor between the elastic protrusion members. The thickness of the rubber layer is less than the height of the protruding part of the elastic protrusion member.

Description

ROTOR STRUCTURE OF ROTARY POSITIVE DISPLACEMENT PUMP

Technical Field

[1] The present invention relates, in general, to rotor structures of rotary positive displacement pumps and, more particularly, to a rotor structure of a rotary positive displacement pump for compressing fluid, which includes a main rotor, which rotates at the center of a casing of the pump, a subsidiary rotor, which rotates at a position adjacent to the main rotor in a state of being in contact with the main rotor, and a plurality of elastic protrusion members, which are provided in each compressing protrusion of the main and subsidiary rotors, so that the elastic protrusion members prevent the compressing protrusions and depressions, into which associated compressing protrusions are inserted when the main and subsidiary rotors are rotated, from interfering with each other, thus increasing the flow rate and the pump head of the pump, even if the pump is relatively small, and ensuring superior performance of the pump at a high speed as well as at a low speed. Background Art

[2] Generally, a centrifugal pump, which is one of the available kinds of pumps, ensures a relatively high flow rate but has a limited pump head. Thus, as the head coefficient increases, the efficiency of the centrifugal pump reduces. Furthermore, to increase the flow rate of the centrifugal pump, the volume of the pump must be increased, thereby it is difficult to satisfy the recent trend towards smallness and lightness. In addition, there is a disadvantage in that the pump cannot conduct its intended function at a low speed.

[3] Meanwhile, a gear pump, which is a kind of conventional rotary positive displacement pumps, has a relatively high pump head and can conduct its intended function even at a high rotating speed. However, there are problems in that the flow rate of the pump is relatively low, the efficiency of the pump is reduced at a low speed, and noise occurs and gears are worn at high pressure and at a high rotating speed.

[4] Therefore, a pump that ensures a high flow rate and a high pump head, is able to conduct its intended function at a high speed as well as at a low speed, that is, regardless of the rotating speed, and ensures high efficiency and superior performance has been required.

[5] Meanwhile, a rotary positive displacement pump that satisfies the above requirements was proposed in Korean Patent Registration No. 127650, which was filed by the inventor of the present invention. However, this rotary positive displacement pump is problematic in that efficiency is reduced at a low flow rate, impact is applied to rotors and a casing when the rotors are rotated, and the sealing ability is poor.

[6] In an effort to overcome the above-mentioned problems, another rotary positive displacement pump, in which a plurality of separation pins is provided in main and subsidiary rotors and elastic material is applied to the surface thereof by molding, was proposed in Korean Utility Model Registration No. 20-0239382. However, when the main rotor and the subsidiary rotor are rotated, pressure is directly applied to the elastic layer applied to the main rotor and the subsidiary rotor. Furthermore, due to friction between contact parts of the main rotor and the subsidiary rotor, there is a problem in that the elastic layer is worn. Disclosure of Invention Technical Problem

[7] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a rotor structure of a rotary positive displacement pump, the main rotor and subsidiary rotor of which have improved shapes and structures, thus markedly increasing the flow rate of the pump, reducing impact with a casing of the pump, and improving the seal between the main and subsidiary rotors and the casing of the pump. Technical Solution

[8] In order to accomplish the above object, the present invention provides a rotor structure of a rotary positive displacement pump, including a main rotor fitted over a rotating shaft provided at a central position in a casing of the pump and having a plurality of compressing protrusions thereon, and a subsidiary rotor rotating at a position adjacent to the main rotor and having a plurality of compressing protrusions thereon. A plurality of seating grooves, each of which is open at one side, is formed in a surface of the compressing protrusions of the main rotor and the subsidiary rotor at positions spaced apart from each other at regular intervals, an elastic protrusion member, which has leakage prevention and fluid compression functions and has a "β" shape, is seated into each of the seating grooves, and rubber layers are applied on respective circumferential outer surfaces of the main rotor and the subsidiary rotor between the elastic protrusion members. A thickness of each rubber layer is less than a height of a protruding part of each elastic protrusion member.

Advantageous Effects

[9] The present invention, of course, has the effects of a typical rotary positive displacement pump, in which the pump head is high and superior performance is exhibited regardless of the rotating speed. As well, in the rotary positive displacement pump according to the present invention, the shapes of a main rotor and a subsidiary rotor are improved compared to the conventional art, and a plurality of elastic protrusion members is provided in the main and subsidiary rotors, thus increasing the capacity and efficiency of the pump, and extending the lifetime of the pump thanks to reduced friction and impact during pumping operation.

Brief Description of the Drawings

[10] FlG. 1 is an exploded perspective view showing the structures of a main rotor and a subsidiary rotor of a rotary positive displacement pump according to an embodiment of the present invention;

[11] FlG. 2 is a sectional view showing the engagement structure between the main rotor and the subsidiary rotor according to the present invention;

[12] FIGS. 3 through 5 are views showing examples of an engagement structure of a main rotor and a subsidiary rotor of a rotary positive displacement pump according to the present invention; and

[13] FlG. 6 is a view showing the operation of the main rotor and the subsidiary rotor according to the present invention. Best Mode for Carrying Out the Invention

[14] Hereinafter, the present invention will be described in detail with reference to the attached drawings.

[15] FlG. 1 is an exploded perspective view showing the structures of a main rotor 10 and a subsidiary rotor 20 of a rotary positive displacement pump according to the present invention. FlG. 2 is a sectional view showing the engagement structure between the main rotor 10 and the subsidiary rotor 20.

[16] Referring to the drawings, the rotor structure of the rotary positive displacement pump of the present invention includes the main rotor 10, which is fitted over a rotating shaft provided at the center in a casing of the pump and has a plurality of compressing protrusions 12 on the circumferential outer surface thereof and carrying depressions 14 defined between the compressing protrusions 12, and the subsidiary rotor 20, which is rotated in place at a position engaging with the main rotor 10 and has a plurality of compressing protrusions 24 on the circumferential outer surface thereof and carrying depressions 26 defined between the compressing protrusions 24.

[17] Furthermore, a plurality of seating grooves 40, each of which is open at one side, is formed in the surface of the compressing protrusions 12 and 24 of the main rotor 10 and the subsidiary rotor 20 at positions spaced apart from each other at regular intervals. An elastic protrusion member 16, 22, which has leakage prevention and fluid compression functions and has a "β" shape, is seated in each seating groove 40. Rubber layers are applied on respective circumferential outer surfaces of the main rotor and the subsidiary rotor between the elastic protrusion members. The thickness of the rubber film 42 is less than the height of the protruding part of the elastic protrusion member 16, 22.

[18] In the present invention, when the main rotor 10 and the subsidiary rotor 20 are rotated, the elastic protrusion member 22 of the subsidiary rotor 20 is positioned between the elastic protrusion members 16 provided in the compressing protrusion 12 of the main rotor 10.

[19] Meanwhile, as shown in FIGS. 3 through 5, the ratio of the number of revolutions between the main and subsidiary rotors 10 and 20 may be changed by changing the number of compressing protrusions of the main and subsidiary rotors 10 and 20. It is preferable that the ratio of the number of compressing protrusions of the subsidiary rotor 20 to the number of compressing protrusions of the main rotor 10 be 1 :2 or 1 :3.

[20] The operation and effect of the present invention having the above-mentioned structure will be explained herein below. As shown in FlG. 6, the main rotor 10 and the subsidiary rotor 20 are coupled to each other through gears (not shown), which are provided on the rotating shafts. When the main rotor 10 is rotated by power transmitted from a motor or the like, the subsidiary rotor 20, which engages with the main rotor 10 through the gears, is simultaneously rotated in the opposite direction.

[21] One compressing protrusion 12 of the main rotor 10, which has entered a carrying depression 24 between compressing protrusions 24 of the subsidiary rotor 20, moves while engaging a compressing protrusion 24 of the subsidiary rotor 20 and exits the compressing protrusion 24. A subsequent compressing protrusion 12 of the main rotor 10 enters a subsequent carrying depression 24 between compressing protrusions 24 of the subsidiary rotor 20. This operation is repeated.

[22] During the above process, fluid around the inlet 34 of the pump is carried to an outlet 36 through the carrying depressions 14 of the main rotor 10. That is, fluid is forcibly carried from the inlet 24 to the outlet 36 of the pump. The pumping operation is conducted by repeating such process.

[23] In the present invention, the main rotor 10 and the subsidiary rotor 20 have shapes such that a contact line is defined on a circle forming the carrying depressions 14 of the main rotor 10. Therefore, friction and impact are markedly reduced during rotation of the rotors, while the sealing ability thereof is markedly increased.

[24] Furthermore, to prevent the fluid pressure and the flow rate of the pump from being reduced by the backflow of fluid through gaps between the main rotor 10 and the subsidiary rotor 20, between the subsidiary rotor 20 and the casing 11 of the pump, and between the main rotor 10 and the casing 11 of the pump, and thus to prevent the efficiency from being reduced, the elastic protrusion members 16 and 22 for fluid leakage prevention and for compressing fluid are provided in the respective seating grooves 40 formed in the compressing protrusions 12 and 24 of the main and subsidiary rotors 10 and 20. Therefore, the elastic protrusion members 16 and 22 of the present invention prevent gaps from occurring between elements during the operation of the pump, thus increasing the performance of the pump and extending the lifetime of the pump.

[25] As such, the present invention increases the sealing ability of the pump and thus has the advantages of increasing the performance of the pump and extending the lifetime of the pump.

[26] In addition, in the present invention, the efficiency of the pump may be increased by appropriately changing the construction of the casing 11 depending on the installation conditions and the intended purpose of the pump.

[27] Meanwhile, as shown in FIGS. 3 through 5, the geometrical shapes of the main and subsidiary rotors 10 and 20 are determined by the size ratio and the ratio of the number of revolutions between the main rotor 10 and the subsidiary rotor 20. Furthermore, depending on the number of depressions formed in the subsidiary rotor 20 and on the number of compressing protrusions provided on the main rotor 10, the pump has a 5x10, 4x8 or other structure. As well, depending on the ratio of the number of revolutions between the main rotor 10 and the subsidiary rotor 20, the shape of the depressions may be changed.

[28] In other words, the shape of the main rotor 10 is changed depending on the ratio of the number of revolutions between the main rotor and the subsidiary rotor and depending on the number of compressing protrusions thereof, and the shape of the subsidiary rotor 20 is determined by the shape of the main rotor. The reason for this is that, because there is a basic characteristic in which the subsidiary rotor is rotated along with the main rotor while maintaining the state of engagement with the main rotor, there is only one shape for the subsidiary rotor that corresponds to a given shape of the main rotor.

[29] Meanwhile, typically, a plurality of subsidiary rotors 20 is provided around one main rotor 10 in the casing. An inlet 34 and an outlet 36 are formed at respective opposite sides of each subsidiary rotor 20 in the casing, in which the main rotor 10 and the subsidiary rotors 20 are installed. Furthermore, a close contact part is provided in the casing between the subsidiary rotors 20, so that the main rotor 10 is in close contact with the close contact part while rotating.

[30] In addition, an inlet path, which is connected to the inlet, and an outlet path, which is connected to the outlet, are formed at predetermined positions in the casing.

[31] Hereinafter, construction examples of the pump to embody the present invention will be explained in detail with reference to the attached drawings.

[32] FIGS. 3 through 5 are partial sectional views showing examples of installation of the main rotors 10 and the subsidiary rotors 20 in the casing 11. In these examples, the ratio of the number of revolutions between the main rotor 10 and the subsidiary rotor 20 is 1 :2. Because the ratio of the number of depressions 26 of the subsidiary rotor 20 to the number of compressing protrusions 12 of the main rotor 10 must be 1 :2 in order to rotate the main and subsidiary rotors 10 and 20 without interference between the compressing protrusions 12 of the main rotor 10 and the depressions 26 of the subsidiary rotor 20, in the example of FlG. 3, the number of depressions 26 of the subsidiary rotor 20 is five and the number of compressing protrusions 12 of the main rotor 10 is ten.

[33] Furthermore, one main rotor 10 and two subsidiary rotors 20 are provided in the casing 11.

[34] Here, the space defined between adjacent compressing protrusions 12 of the main rotor 10 is the space for carrying fluid.

[35] In the example shown in FlG. 4, the number of depressions 26 of the subsidiary rotor 20 is four, and the number of compressing protrusions 12 of the main rotor 10 is eight.

[36] Furthermore, two main rotors 10 and four subsidiary rotors 20 are provided in the casing 11.

[37] FlG. 5 illustrates another example in which the number of depressions 26 and the number of compressing protrusions 12 are changed depending on the rotating speed ratio of the rotors. In the example shown in FlG. 5, the number of depressions 26 of the subsidiary rotor 20 is three, and the number of compressing protrusions 12 of the main rotor 10 is six, so that they are provided at a ratio of 1 :2.

[38] In this case, the shapes of the main rotor 10 and the subsidiary rotor 20 are different from those of FIGS. 1 and 2. The geometrical shape of the subsidiary rotor 20 is determined depending on the number of compressing protrusions 12 of the main rotor 10.

[39] The inlets 34 and the outlets 36 are defined at opposite sides of each subsidiary rotor 20 in the casing 11. Furthermore, close contact parts 30 are provided in the casing 11 between the two related subsidiary rotors 20 and between the inlet 34 and the related outlet 36, so that the maximum outer diameters of the main and subsidiary rotors 10 and 20 are in close contact with the close contact parts 30, thus maintaining the sealed state during the rotation of the main and subsidiary rotors 10 and 20. Industrial Applicability

[40] As described above, as well as the effects of a typical rotary positive displacement pump, in which the pump head is high and superior performance is exhibited regardless of the rotating speed, in the rotary positive displacement pump according to the present invention, the shapes of a main rotor and a subsidiary rotor are improved compared to the conventional art, and a plurality of elastic protrusion members is provided in the main and subsidiary rotors, thus increasing the capacity and efficiency of the pump, and extending the lifetime of the pump thanks to reduced friction and impact during pumping operation.

[41] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

[42]

[43]

Claims

[1] A rotor structure of a rotary positive displacement pump, comprising a main rotor fitted over a rotating shaft provided at a central position in a casing of the pump and having a plurality of compressing protrusions thereon, and a subsidiary rotor rotating at a position adjacent to the main rotor and having a plurality of compressing protrusions thereon, wherein a plurality of seating grooves, each of which is open at one side, is formed in a surface of the compressing protrusions of the main rotor and the subsidiary rotor at positions spaced apart from each other at regular intervals, an elastic protrusion member, which has leakage prevention and fluid compression functions and has a "β" shape, is seated into each of the seating grooves, and rubber layers are applied on respective circumferential outer surfaces of the main rotor and the subsidiary rotor between the elastic protrusion members, wherein a thickness of each rubber layer is less than a height of a protruding part of each elastic protrusion member.

[2] A rotor structure of a rotary positive displacement pump, comprising a main rotor fitted over a rotating shaft provided at a central position in a casing of the pump and having a plurality of compressing protrusions thereon, and a subsidiary rotor rotating at a position adjacent to the main rotor and having a plurality of compressing protrusions thereon, wherein a plurality of seating grooves, each of which is open at one side, is formed in a surface of the compressing protrusions of the main rotor and the subsidiary rotor at positions spaced apart from each other at regular intervals, an elastic protrusion member, which has leakage prevention and fluid compression functions and has a "β" shape, is seated into each of the seating grooves, and rubber layers are applied on respective circumferential outer surfaces of the main rotor and the subsidiary rotor between the elastic protrusion members, wherein a thickness of each rubber layer is less than a height of a protruding part of each elastic protrusion member.