WO2018226009A1

WO2018226009A1 - Pump with vacuum, self-priming, and booster functions

Info

Publication number: WO2018226009A1
Application number: PCT/KR2018/006392
Authority: WO
Inventors: Yong Kwon Koh; Jang Soon Kwon; Min Hoon Baik; Jae Kwang Lee
Original assignee: Korea Atomic Energy Research Institute
Priority date: 2017-06-09
Filing date: 2018-06-05
Publication date: 2018-12-13
Also published as: KR101881546B1

Abstract

Disclosed herein is a pump with vacuum, self-priming, and booster functions, which includes a rotor housing, a rotor, an upper chamber, a lower chamber beneath the rotor housing, an inlet check valve, an outlet check valve, and an introduction passage connecting the inlet port of the upper chamber to the lower chamber.

Description

PUMP WITH VACUUM, SELF-PRIMING, AND BOOSTER FUNCTIONS

The present invention relates to a pump with vacuum, self-priming, and booster functions, and more particularly, to a pump capable of performing all vacuum, self-priming, and booster functions using a rotary piston pump in which suction, compression, and discharge are performed by a rotating triangular rotor.

German F. Wankel finished the principle of the rotary engine that can generate power only by rotation in 1951. German NSU Motorenwerke AG succeeded in the industrialization of rotary engines around 1960, and had sold compact sports cars with rotary engines since 1963. Thereafter, many manufacturers around the world have studied rotary engines, and, for example, Japanese Mazda Motor Corporation mounted rotary engines to general vehicles.

The so-called Wankel engine is an engine in which a triangular rotor is eccentrically rotated in an epitrochoid curved cylinder, and intake, compression, combustion, and exhaust are performed according to the volume change of three spaces between the rotor and the cylinder. The Wankel engine has a small loss of power because it does not reciprocate unlike pistons, and is therefore advantageous in that it is able to generate high power and smoothly rotate.

Korean Patent No. 10-1655160 discloses a rotary piston pump that compresses a fluid using the principle of the Wankel engine.

The rotary piston pump disclosed in the patent document uses the fact that the space within a rotor housing is repeatedly compressed and expanded by the eccentric rotation of a triangular rotor, and includes a pair of inlet and outlet check valves installed on each of both sides of the rotor housing with the built-in triangular rotor to suck, compress, and discharge a fluid.

The rotary piston pump is advantageous in that it is able to not only transfer a relatively large amount of fluid, but also generate a high pressure, compared to an existing piston reciprocating pump.

Fig. 1 illustrates an example of a rotary piston pump, wherein inlet and outlet check valves are illustrated on the side of a rotor housing for convenience sake. The rotary piston pump illustrated in Fig. 1 has an epitrochoid curved space 1a defined within a rotor housing 1, and includes a triangular rotor 2 installed in the space 1a. The rotor 2 is installed to a circular eccentric member 4 fixed to a rotary shaft 3 so as to rotate freely, thereby sucking a fluid into the space 1a, compressing it therein, and discharging it therefrom while eccentrically rotating about the rotary shaft 3.

Meanwhile, the rotary piston pump includes a pair of

inlet check valves

5a and 5b and a pair of

outlet check valves

6a and 6b, which are installed to communicate with the space 1a in the rotor housing 1. The rotor 2 partitions the space 1a into three variable volume spaces A, B, and C. The rotor 2 increases or decreases (forms a negative pressure or a positive pressure) the volumes of the variable volume spaces A, B, and C while rotating. Thus, in the case where a positive pressure is formed, a fluid is discharged while the inlet check valves communicating with the variable volume spaces having the positive pressure is closed and the outlet check valves are opened. On the other hand, in the case where a negative pressure is formed, a fluid is sucked while the outlet check valves communicating with the variable volume spaces having the negative pressure is closed and the inlet check valves are opened. In this case, the positions of the variable volume spaces A, B, and C vary depending on the rotational position of the rotor 2.

Meanwhile, sealing must be securely carried out between the variable volume spaces A, B, and C in order to smoothly and strongly suck and compress a fluid by the rotor 2. For example, a vane 7 may be installed at each corner of the rotor 2 such that the vane 7 is pressed against the inner peripheral surface of the space 1a, as illustrated in Fig. 2. The vane 7 may be implemented in such a manner that it is pushed by an elastic body 8 to be pressed against the inner peripheral surface of the space 1a.

However, the force of the elastic body 8 for pushing the vane 7 to the inner peripheral surface of the space 1a is constant. Hence, if the pressures in the variable volume spaces A, B, and C are increased due to an increase in rotational speed of the pump, the sealing between variable volume spaces A, B, and C is not kept by the vane 7 after any point in time, resulting in a leakage of fluid therebetween. For this reason, if the fluid-tightness between variable volume spaces A, B, and C is deteriorated, the compression performance of the pump is degraded.

In addition, if a lubricant such as oil is not supplied in the initial stage of operation of the pump, sliding friction necessarily occurs between the rotor 2 and the eccentric member 4, between the rotor 2 and the upper cover (not shown) of the rotor housing 1, and between the rotor 2 and the lower cover (not shown) of the rotor housing 1 when the rotor 2 rotates, which may lead to heating and material deformation.

[Related Document]

[Patent Document]

(Patent Document) Korean Patent No. 10-1655160 (September 01, 2016)

Accordingly, the present invention has been made in view of the above-mentioned problem, and an object thereof is to provide a pump with vacuum, self-priming, and booster functions, capable of reducing friction caused by rotation of a rotor.

Another object of the present invention is to provide a pump with vacuum, self-priming, and booster functions, capable of improving fluid-tightness between variable volume spaces.

A further object of the present invention is to provide a pump with vacuum, self-priming, and booster functions, which is usable as all of vacuum, self-priming, and booster pumps.

In accordance with an aspect of the present invention, a pump with vacuum, self-priming, and booster functions includes a rotor housing having a space defined therein, a rotor installed in the space of the rotor housing and partitioning the space into a plurality of variable volume spaces while eccentrically rotating about a rotary shaft, an upper chamber installed above the rotor housing and having inlet and outlet ports formed at both sides thereof, a liquid being injected into the upper chamber, a lower chamber beneath the rotor housing, the liquid being injected into the lower chamber, an inlet check valve installed within the lower chamber to be opened and closed according to a change in pressure in the variable volume spaces, thereby sucking the fluid in the lower chamber to the space of the rotor housing, an outlet check valve installed within the upper chamber to be opened and closed according to the change in pressure in the variable volume spaces, thereby discharging the fluid in the space of the rotor housing to the upper chamber, and an introduction passage connecting the inlet port of the upper chamber to the lower chamber.

In accordance with the present invention, the liquid (oil or water) provided in the internal space of a pump performs a lubricant function for smooth rotation of a rotor and a sealing function between the corner of the rotor and the inner peripheral surface of a rotor housing.

Therefore, the pump according to the present invention can be used as a vacuum pump and an air booster pump since air is smoothly sucked, compressed, and discharged when the pump is initially operated in the air.

In addition, the pump according to the present invention can be used as a self-priming pump and a liquid booster pump, which more rapidly and easily suck and discharge liquid by the liquid provided in the pump when the inlet pipe of the pump is connected to a liquid reservoir.

In addition, since the liquid provided in the pump according to the present invention performs a sealing function, there is no need for the vane installed at the corner of an existing rotor. Therefore, the pump has a simple configuration since the number of parts is reduced.

In addition, since the pump according to the present invention does not require a vane, friction is not directly caused between the rotor and the inner peripheral surface of the rotor housing. Therefore, the pump has an improved efficiency by a reduction in friction loss.

In addition, since friction is not directly caused between the rotor and the inner peripheral surface of the rotor housing in the pump according to the present invention, heating is reduced in operation, and the pump is cooled by the water provided therein even though heating is caused. Therefore, the safety of the pump against heating is improved.

In addition, both of fluid and air sucked into a lower chamber are discharged to an upper chamber in the pump according to the present invention, in which case the air in the lower chamber more rapidly flows to the upper chamber by the synergy of fluid and air. Therefore, it is possible to rapidly reach a desired degree of vacuum, compared to when the pump is used as a vacuum pump.

In addition, the liquid in the upper chamber is supplied to the lower chamber since the upper and lower chambers are interconnected by a circulation passage in the pump according to the present invention. Therefore, the pump can function as a self-priming pump since the level of liquid at the inlet-side of the inlet check valve is maintained in a certain range.

In addition, in the pump according to the present invention, a floating valve installed at the lower end of the circulation passage in the lower chamber closes the circulation passage when a positive pressure is formed in the upper chamber, thereby blocking the upper and lower chambers. Therefore, it is possible to generate high pressure and transfer a large amount of fluid.

Fig. 1 is a schematic view illustrating a conventional rotary piston pump.

Fig. 2 is a perspective view illustrating a rotor of the conventional rotary piston pump.

Fig. 3 is a perspective view illustrating a pump with vacuum, self-priming, and booster functions according to an embodiment of the present invention.

Fig. 4 is an exploded perspective view illustrating the pump with vacuum, self-priming, and booster functions according to the embodiment of the present invention.

Fig. 5 is an internal schematic view illustrating the pump with vacuum, self-priming, and booster functions according to the embodiment of the present invention.

Fig. 6 is a top cross-sectional view illustrating a rotor installation portion of the pump with vacuum, self-priming, and booster functions according to the embodiment of the present invention, wherein positions of suction and discharge ports are indicated on the plane.

Fig. 7 and Fig. 8 are views for explaining a state of operation of the pump with vacuum, self-priming, and booster functions according to the embodiment of the present invention.

Fig. 9 and Fig. 10 correspond to Fig. 7 and Fig. 8, respectively, and are views for explaining a state in which inlet and outlet check valves are opened and closed according to the rotation of a rotor.

Fig. 11 is a view illustrating another example of a floating valve as one component of the present invention.

Fig. 12 is a view illustrating a further example of the floating valve.

Various variations may be performed on exemplary embodiments of the present invention and the embodiments of the present invention can be embodied in different forms. Reference will now be made in detail to specific exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. However, the present invention will not be limited only to the specific exemplary embodiments of the present invention which are disclosed herein. Therefore, it should be understood that the scope and spirit of the present invention can be extended to all variations, equivalents, and replacements in addition to the accompanying drawings of the present invention. In the drawings, the thickness of each line, the size of each component, or the like may be exaggerated and schematically illustrated for convenience of description and clarity.

In addition, the terms used in the specification are terms defined in consideration of functions of the present invention, and these may vary with the intention or practice of a user or an operator. Therefore, these terms should be defined based on the entire content disclosed herein.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 3 is a perspective view illustrating a pump with vacuum, self-priming, and booster functions according to an embodiment of the present invention. Fig. 4 is an exploded perspective view illustrating the pump with vacuum, self-priming, and booster functions according to the embodiment of the present invention. Fig. 5 is an internal schematic view illustrating the pump with vacuum, self-priming, and booster functions according to the embodiment of the present invention. Fig. 6 is a top cross-sectional view illustrating a rotor installation portion of the pump with vacuum, self-priming, and booster functions according to the embodiment of the present invention, wherein positions of suction and discharge ports are indicated on the plane.

Referring to Figs. 3 to 6, the pump with vacuum, self-priming, and booster functions according to the embodiment of the present invention includes a rotor housing 10, a rotor 20, a rotary shaft 30, an upper cover 40, a lower cover 50, an upper chamber 60, a lower chamber 70,

inlet check valves

100 and 110, and

outlet check valves

120 and 130.

The rotor housing 10 has an epitrochoid curved space 11 defined therein, and the rotor 2 is installed in the space 11.

The rotor 20 has a substantially triangular shape, and rotates in the state in which three corners thereof are in contact with the inner peripheral surface of the space 11.

The rotor 20 has an eccentric member 31 formed therein, and the eccentric member 31 rotates freely relative to the rotor 20. The rotary shaft 30 is fixed through the eccentric member 31 at an eccentric position relative thereto. The rotary shaft 30 and the eccentric member 31 may be integrally manufactured. Thus, when the rotary shaft 30 rotates, the rotor 20 is eccentrically rotated about the rotary shaft 30 by the eccentric member 31. As such, the suction, compression, and discharge of a fluid are performed while three spaces (variable volume spaces A, B, and C (see Figs. 9 and 10)) partitioned by the corners of the rotor 20 are increased in volume by the eccentric rotation of the rotor 20.

The upper cover 40 is tightly installed on the upper surface of the rotor housing 10, the rotary shaft 30 passes through the center of the upper cover 40, and the upper cover 40 has

discharge ports

41 and 42 formed at opposite positions (e.g., with an angle difference of 180°) with respect to the rotary shaft 30. The

discharge ports

41 and 42 are opened and closed by the operation of the

outlet check valves

120 and 130.

The

discharge ports

41 and 42 are formed within a size range corresponding to the space 11, as illustrated in Fig. 6, and does not overlap with the rotation range of the eccentric member 31 (see Fig. 6).

The lower cover 50 is tightly installed on the lower surface of the rotor housing 10, the rotary shaft 30 passes through the center of the lower cover 50, and the lower cover 50 has

suction ports

51 and 52 formed at opposite positions (e.g., with an angle difference of 180°) with respect to the rotary shaft 30. The

suction ports

51 and 52 are opened and closed by the operation of the

inlet check valves

100 and 110.

The

discharge ports

41 and 42 and the

suction ports

51 and 52 are preferably formed at positions with a rotational angle difference of 90° when viewed from the top as in Fig. 6. That is, they are formed at axisymmetric positions on the basis of a lateral centerline (not shown) bisecting the space 11 of the rotor housing 10. Meanwhile, although the embodiment of the present invention is described on the premise that a pair of discharge ports and a pair of suction ports are provided, the number of discharge and suction ports may also be changed within a range in which the discharge and suction ports are used to perform the same function (suction, compression, and discharge functions). That is, within the range in which the discharge and suction ports are used to perform the same function (suction, compression, and discharge functions), a different number of discharge and suction ports will be included within the technical scope of the present invention. The same is applied to openings, inlet check valves, and outlet check valves which will be described later.

The upper and

lower covers

40 and 50 are tightly installed on the respective upper and lower surfaces of the rotor housing 10 to improve the sealing performance of the space 11 of the rotor housing 10 and provide portions for formation of the

suction ports

51 and 52 and the

discharge ports

41 and 42.

The upper chamber 60 has an empty space defined therein, and is tightly installed on the upper surface of the upper cover 40. The upper chamber 60 has an inlet port 61 formed at one side thereof, and an outlet port 62 formed at the other side thereof. In addition, the upper chamber 60 has a pair of openings 63 and 64 (see Fig. 5) formed on the lower surface thereof for communication with the

respective discharge ports

41 and 42 of the upper cover 40.

The lower chamber 70 also has an empty space defined therein, and is tightly installed on the lower surface of the lower cover 50. The lower chamber 70 has a pair of

openings

71 and 72 formed on the upper surface thereof for communication with the

respective suction ports

51 and 52 of the lower cover 50. Meanwhile, although the embodiment of the present invention is described on the premise that a pair of openings and a pair of openings communicating with the respective discharge ports and suction ports are provided, the number of openings may also be changed within a range in which the openings are used to perform the same function (suction, compression, and discharge functions). That is, within the range in which the openings are used to perform the same function (suction, compression, and discharge functions), a different number of openings will be included within the technical scope of the present invention. The same is applied to inlet check valves and outlet check valves which will be described later.

A predetermined amount of liquid (water or oil) is injected into the upper and

lower chambers

60 and 70. The liquid (water or oil) serves as a lubricant and a coolant by acting on the friction portion of the rotor 20 when the pump is driven, and also performs sealing and self-priming functions.

The upper and

lower chambers

60 and 70 define sealed spaces communicating with respective outlet- and inlet-sides of the pump to provide a space into which the liquid is injected, and these spaces are interconnected by a circulation passage 90 to be described later to provide a space for circulation of the injected liquid.

In the assembled state, an introduction passage 80 is formed at one side of the pump to connect the inlet port 61 of the upper chamber 60 to the lower chamber 70. The introduction passage 80 is defined by passage holes 81, 82, 83, 84, and 85 that are respectively formed through the lower surface of the upper chamber 60, the upper cover 40, the rotor housing 10, the lower cover 50, and the upper surface of the lower chamber 70. All the passage holes 81, 82, 83, 84, and 85 are vertically formed at the same position.

The inner end of the inlet port 61 is bent and extends downward so as to be connected to the upper end of the introduction passage 80, namely to the passage hole 81 of the upper chamber 60.

The introduction passage 80 serves to guide gas or liquid, which is introduced through the inlet port 61 from the outside, to the suction-side of the pump, namely to the installation portions of the

inlet check valves

100 and 110 to be described later.

In the assembled state, a circulation passage 90 is formed at the other side of the pump to connect the upper chamber 60 to the lower chamber 70. The circulation passage 90 is defined by passage holes 91, 92, 93, 94, and 95 that are respectively formed through the lower surface of the upper chamber 60, the upper cover 40, the rotor housing 10, the lower cover 50, and the upper surface of the lower chamber 70. All the passage holes 91, 92, 93, 94, and 95 are vertically formed at the same position.

The circulation passage 90 connects the upper chamber 60 to the lower chamber 70 to circulate the liquid in the upper chamber 60 to the lower chamber 70 so that the liquid is continuously supplied to the lower chamber 70 without fluid introduced from the outside even while the pump sucks and discharges gas, thereby enabling lubricating, cooling, sealing, and self-priming functions to be continuously performed by the liquid. In connection with the circulation passage 90, the pump according to the embodiment of the present invention may further include a means for opening and closing the circulation passage 90 (e.g., a floating valve 140 or the like to be described later).

The pair of

inlet check valves

100 and 110 are installed on the upper surface of the lower chamber 70. The

inlet check valves

100 and 110 are installed beneath the

respective openings

71 and 72 of the lower chamber 70.

The pair of

outlet check valves

120 and 130 are installed on the bottom surface of the upper chamber 60. The

outlet check valves

120 and 130 are installed above the

respective openings

63 and 64 of the upper chamber 70.

The

inlet check valves

100 and 110 permit only suction of a fluid into the space 11 of the rotor housing 10 from the lower chamber 70, and prevent the back flow of the fluid in an opposite direction.

The

outlet check valves

120 and 130 permit only discharge of a fluid to the upper chamber 60 from the space 11 of the rotor housing 10, and prevent the back flow of the fluid in an opposite direction.

Each of the

inlet check valves

100 and 110 and the

outlet check valves

120 and 130 is installed within a valve housing 102, and is elastically supported by a spring 101 in a direction (downward direction) opposite to the flow direction (upward direction) of a fluid. Thus, each check valve opens and closes an inlet formed on the lower surface of the associated valve housing accommodating the check valve. Although reference numerals of the valve housing and the spring are illustrated only with respect to one inlet check valve 100, it can be seen in Fig. 5 that the same configuration is applied to the

other check valves

110, 120, and 130.

The inlets formed on the lower surfaces of the valve housings of the

inlet check valves

100 and 110 communicate with the internal space of the lower chamber 70, and the upper surfaces of the valve housings are formed with outlets that communicate with the

openings

71 and 72 of the lower chamber 70.

The inlets formed on the lower surfaces of the valve housings of the

outlet check valves

120 and 130 communicate with the

openings

63 and 64 of the upper chamber 60, and the upper surfaces and both sides of the valve housings are all formed with outlets so that the sucked fluid is smoothly discharged to the internal space of the upper chamber 60. Meanwhile, although the embodiment of the present invention is described on the premise that a pair of inlet check valves and a pair of outlet check valves are provided, the number of inlet and outlet check valves may also be changed within a range in which the inlet and outlet check valves are used to perform the same function (suction, compression, and discharge functions). That is, within the range in which the inlet and outlet check valves are used to perform the same function (suction, compression, and discharge functions), a different number of inlet and outlet check valves will be included within the technical scope of the present invention.

Meanwhile, the pump according to the embodiment of the present invention may further include a floating valve 140 that is installed within the lower chamber 70 to open and close the circulation passage 90. In detail, the floating valve 140 is installed to the lower end of the circulation passage 90, namely to the lower surface of the passage hole 95, and is a floating body (e.g., may have a hollow structure) capable of floating in the liquid by buoyancy.

Meanwhile, the pump according to the embodiment of the present invention may further include a floating valve housing 141 that provides a space for installation of the floating valve 140.

The floating valve housing 141 has a passage formed vertically therethrough for communication between the circulation passage 90 and the lower space of the lower chamber 70, and has an elevation space 142 defined in the middle of the passage for installation of the floating valve 140 therein so that the elevation space 142 has a larger cross-sectional area than the passage.

The lower portion of the floating valve housing 141 extends downward to be submerged in the liquid injected into the lower chamber 70, and the liquid is introduced into the passage of the floating valve housing 141, so that buoyancy acts on the floating valve 140 to float the floating valve 140.

The floating valve 140 has a cross-sectional area that is smaller than the elevation space 142 while being larger than the passage of the floating valve housing 141.

Accordingly, the upper inlet of the elevation space 142 is blocked by the floating valve 140 to close the passage when the floating valve 140 is fully moved up, whereas the lower outlet of the elevation space 142 is blocked by the floating valve 140 to close the passage when the floating valve 140 is fully moved down. Otherwise, the passage is opened. That is, the circulation passage 90 is opened and closed according to the vertical position of the floating valve 140.

The lower chamber 70 has a basic level of liquid under which the inlets of the valve housings of the

inlet check valves

100 and 110 are submerged in the liquid in the state in which the pump is not operated, wherein although it is considered that the basic level of liquid is indicated by line A of Fig. 7 and the liquid is a liquid other than water, the line A is used as a basic level of water A while focusing on water for convenience of description hereinafter.

The floating valve 140 is installed such that it floats up from the basic level of water by buoyancy to block the upper inlet of the elevation space 142 and close the circulation passage 90.

A small amount of water is injected into the upper chamber 60 to a lower position than the bottom of the outlet port 62 (level of water B).

Meanwhile, a mechanical seal 150 may be installed at the upper portion of the rotary shaft 30 to prevent a leakage of fluid through the gap between the rotary shaft 30 and the upper chamber 60, and a bearing 160 may be installed at the lower end of the rotary shaft 30 to rotatably support the rotary shaft 30. Although the mechanical seal 150 and the bearing 160 is illustrated to be each installed only at one place, they may, of course, be additionally installed at places requiring sealing and support of the rotary shaft,

The operation and effect of the pump with vacuum, self-priming, and booster functions according to the present invention will be described now.

Fig. 7 and Fig. 8 are views for explaining a state of operation of the pump with vacuum, self-priming, and booster functions according to the embodiment of the present invention. Fig. 9 and Fig. 10 correspond to Fig. 7 and Fig. 8, respectively, and are views for explaining a state in which the inlet and outlet check valves are opened and closed according to the rotation of the rotor. Although Figs. 9 and 10 illustrate that the check valve is of a ball type for convenience of description, there is no difference in application of principles.

First, the case will be described in which the pump according to the present invention is used as a vacuum pump and an air compression pump.

Left figure of Fig. 7 illustrates a state before the pump is operated, and the

inlet check valves

100 and 110 and the

outlet check valves

120 and 130 are all closed. It can be seen in left figure of Fig. 9 illustrating the same state that all the check valves are closed since the rotor 20 does not rotate and there is no variation in the internal space of the rotor housing 10. In this case, water is injected into the lower chamber 70 to the basic level of water A, and the upper chamber 60 is filled with water to the level of water B lower than the outlet port 62.

When the rotor 20 begins to rotate counterclockwise, the space A and the space C are decreased in volume and increased in pressure, as seen with reference to right figure of Fig. 9. Thus, both of the

outlet check valves

120 and 130 connected to the spaces A and C are opened, the inlet check valve 100 connected to the expanding space B (in which a negative pressure is formed) is opened, and the inlet check valve 110 connected to the compressed space A is kept closed. That is, only one 100 of the

inlet check valves

100 and 110 is opened, and both of the

outlet check valves

120 and 130 are opened. This is the same as that illustrated in right figure of Fig. 7.

Accordingly, water and air are introduced into the rotor housing 10 through the opened inlet check valve 100 (in which case water is initially sucked and then water and air are sucked in a mixed state due to a drop in the level of water), and then discharged to the upper chamber 60 through the opened

outlet check valves

120 and 130.

The discharged water and air are immediately separated from each other, so that the water is accumulated in the lower portion of the upper chamber 60 and the air is discharged through the outlet port 62.

When water is sucked from the lower chamber 70 as described above, the level of water in the lower chamber 70 drops (A → A') and the floating valve 140 drops at a predetermined level to open the upper inlet of the elevation space 142 and open the circulation passage 90. Thus, the water accumulated in the upper chamber 60 is introduced into the lower chamber 70 through the circulation passage 90.

Consequently, the level of water in the lower chamber 70 rises again and returns back to the basic level of water A, and the floating valve 140 is thus moved up again to close the circulation passage 90.

As such, the water in the lower chamber 70 is circulated in a path in which it flows up to the upper chamber 60 and then flows down back to the lower chamber 70 by allowing the floating valve 140 to be opened due to a drop in the level of water in the lower chamber 70. Therefore, the level of water in the lower chamber 70 repeatedly rises and drops (A ↔ A'). In addition, the level of water in the upper chamber 60 repeatedly rises and drops (B ↔ B') since the suction of water from the lower chamber 70 to the upper chamber 60 and the discharge of water from the upper chamber 60 to the lower chamber 70 are repeated.

As illustrated in left figure of Fig. 8 and left figure of Fig. 10, in the state in which the rotor 20 further rotates, the space A and the space B are compressed so that the pressures therein are increased, and the space C is expanded so that a negative pressure is formed therein. Therefore, both of the

outlet check valves

120 and 130 connected to the spaces A and B are opened, the inlet check valve 100 connected to the space B is closed, and the inlet check valve 110 connected to the space C is opened.

Accordingly, water and air are sucked from the lower chamber 70 through the opened inlet check valve 110 to the inside (space C) of the rotor housing 10, and the water and air compressed in the inside (space A and space B) of the rotor housing 10 are discharged through the

outlet check valves

120 and 130 to the internal space of the upper chamber 60. The discharged water and air are separated from each other as described above, so that the water is accumulated in the lower portion of the upper chamber 60 and the air is discharged through the outlet port 62. The circulation passage 90 is repeatedly opened and closed by the vertical movement of the floating valve 140 according to the change in level of water in the lower chamber 70.

Right figure of Fig. 8 and right figure of Fig. 10 illustrate a state in which the rotor 20 further rotates. In this case, the space A and the space B are expanded so that both of the

inlet check valves

100 and 110 are opened, the outlet check valve 130 connected to the compressed space B is opened, and the outlet check valve 120 connected to the space C is kept closed.

Accordingly, the water and air in the lower chamber 70 are sucked through the

inlet check valves

100 and 110, and then discharged through the outlet check valve 130.

As described above, water and air flow from the lower chamber 70 to the upper chamber 60 while the

inlet check valves

100 and 110 and the

outlet check valves

120 and 130 are opened and closed by a change in pressure according to the volume change of the variable volume spaces A, B, and C, and water is circulated by allowing the circulation passage 90 to be opened and closed by the floating valve 140. Thus, water and air can be continuously sucked since the level of water in the lower chamber 70 is maintained by replenishment of water.

Accordingly, in the case where the inlet port 61 is connected to a closed space such as a container, air is continuously sucked to the closed space and discharged through the outlet port 62 so that vacuum may be formed in the closed space (utilization as a vacuum pump). In the case where a pneumatic line is connected to the outlet port 62, compressed air is continuously discharged through the outlet port 62 so that air pressure may be formed in the pneumatic line (utilization as an air booster pump).

Meanwhile, in the case where the inlet port 61 is connected under water through a pipe or a hose, the suction and discharge of water are increased while the operation of the pump is ongoing, and ultimately the lower and

upper chambers

70 and 60 are completely filled with water. In this case, a negative pressure is formed in the lower chamber 70 into which water is sucked, whereas a positive pressure is formed in the upper chamber 60 from which water is discharged.

Accordingly, after the air introduced into the lower chamber 70 is fully discharged, water is sucked through the inlet port 61 by the negative pressure formed in the lower chamber 70. Then, the sucked water flows to the upper chamber 60 by the rotation of the rotor 20 and is then discharged through the outlet port 62. In this case, the floating valve 140 is fully moved down by the difference in pressure between the upper chamber 60 and the lower chamber 70 to block the lower outlet of the elevation space 142, thereby allowing the circulation passage 90 to be closed.

When the pump continues to operate in the state in which the upper and

lower chambers

60 and 70 are completely filled with water, the pressure relationship between the upper chamber 60 and the lower chamber 70 is not changed. Therefore, the closed state of the circulation passage 90 is continuously maintained by the downward movement of the floating valve 140, thereby rendering the circulation passage 90 nonexistent. In this state, since there is no water flowing from the upper chamber 60 to the lower chamber 70, the water in the upper chamber 60 is fully discharged through the outlet port 62 (utilization as a lifting pump with self-priming function).

In this case, since there is no air in the pump, especially the rotor housing 10, the corners of the rotor 20 are perfectly sealed by water, thereby more securely causing the change in pressure according to the volume change of each variable volume space A, B, or C. Thus, it is possible to lift a large amount of water at higher pressure.

Fig. 11 is a view illustrating another example of the floating valve as one component of the present invention. Fig. 12 is a view illustrating a further example of the floating valve.

The floating valve 140 may be manufactured in the form illustrated in Fig. 11 as well as a simple spherical ball shape.

That is, the floating valve 140 consists of an upper hemisphere, a lower hemisphere, and a cylindrical portion that connects the upper hemisphere to the lower hemisphere. In this case, since the volume of the internal space of the floating valve 140 is increased, compared to when the floating valve 140 has a ball shape, the floating valve 140 more surely responds to buoyancy by the liquid injected into the lower chamber 70. Thus, the floating valve 140 is more smoothly moved up and down. Therefore, the circulation passage 90 is surely opened and closed by the floating valve 140.

In addition, the floating valve 140 may have guide rings 140a that are formed at the respective upper and lower portions of the cylindrical portion and have the same diameter. The guide rings 140a serve to accurately maintain the vertical rectilinear posture and elevation path of the floating valve 140 while sliding along the inner peripheral surface of the elevation space 142 of the floating valve housing 141 when the floating valve 140 moves vertically, thereby securely blocking the upper inlet and lower outlet of the elevation space 142 by the floating valve 140. Preferably, each of the guide rings 140a has a plurality of vertical through-holes (not shown) such that water flows in the body thereof through the circulation passage 90.

In addition, the floating valve 140 may have a plurality of guide protrusions 140b that are formed around the upper and lower portions of the cylindrical portion to slide in the state in which the guide protrusions 140b are in contact with the inner peripheral surface of the elevation space 142. The guide protrusions 140b cause less friction with the inner peripheral surface of the elevation space 142, compared to the guide rings 140a, while performing the same function as the guide rings 140a, thereby more smoothly and vertically moving the floating valve 140 according to the change in level of liquid therein and the pressure relationship between the upper and lower portions thereof. In addition, there is no need to form separate through-holes in the guide protrusions 140b.

This enhancement in performance of the floating valve 140 contributes to further improve the vacuum, self-priming, and booster functions of the pump according to the present invention.

As described above, in the pump with vacuum, self-priming, and booster functions according to the present invention, the liquid (oil or water) injected into the internal space of the pump performs a lubricant function for smooth rotation of the rotor and a sealing function between the corners of the rotor and the inner peripheral surface of the rotor housing.

Therefore, the pump according to the present invention can be used as a vacuum pump and a booster pump since air is smoothly sucked, compressed, and discharged when the pump is initially operated in the air.

In addition, the pump according to the present invention can be used as a self-priming pump and a liquid booster pump, which more rapidly and easily suck and discharge liquid by the liquid provided in the pump even when the inlet pipe of the pump is connected to a liquid reservoir (under water).

In addition, the pump according to the present invention is advantageous in that the number of parts is reduced and the pump has a simple configuration since the liquid provided in the pump performs a sealing function and thus there is no need for the vane installed at the corner of an existing rotor.

In addition, since the pump according to the present invention does not require a vane, the pump has an improved efficiency by a reduction in friction loss between the rotor and the inner peripheral surface of the rotor housing.

In addition, both of fluid and air sucked into the lower chamber are discharged to the upper chamber in the pump according to the present invention, in which case the air in the lower chamber more rapidly flows to the upper chamber by the synergy of fluid and air. Therefore, it is possible to rapidly reach a desired degree of vacuum, compared to when the pump is used as a vacuum pump.

In addition, the liquid in the upper chamber is supplied to the lower chamber since the upper and lower chambers are interconnected by the circulation passage in the pump according to the present invention. Therefore, the pump can continuously function as a self-priming pump since the level of liquid at the inlet-side of the inlet check valve is maintained in a certain range.

In addition, in the pump according to the present invention, the floating valve installed at the lower end of the circulation passage in the lower chamber closes the circulation passage when a positive pressure is formed in the upper chamber, thereby blocking the upper and lower chambers. Therefore, it is possible to generate high pressure and transfer a large amount of fluid.

Although the present invention has been described with reference to the specific embodiments illustrated in the accompanying drawings, it should be understood that numerous other modified and equivalent embodiments may be devised by those skilled in the art that will fall within the intrinsic aspects of the embodiments. Therefore, the technical and protective scope of the present invention should be defined by the following claims.

[Description of Reference Numerals]

10: rotor housing, 11: space

20: rotor, 30: rotary shaft

31: eccentric member, 40: upper cover

41, 42: discharge port, 50: lower cover

51, 52: suction port, 60: upper chamber

61: inlet port, 62: outlet port

63, 64: opening, 70: lower chamber

71, 72: opening, 80: introduction passage

81, 82, 83, 84, 85: passage hole, 90: circulation passage

91, 92, 93, 94, 95: passage hole, 100, 110: inlet check valve

120, 130: outlet check valve, 140: floating valve

141: floating valve housing, 142: elevation space

150: mechanical seal, 160: bearing

Claims

A pump with vacuum, self-priming, and booster functions, comprising:

a rotor housing having a space defined therein;

a rotor installed in the space of the rotor housing and partitioning the space into a plurality of variable volume spaces while eccentrically rotating about a rotary shaft;

an upper chamber installed above the rotor housing and having inlet and outlet ports formed at both sides thereof, a liquid being injected into the upper chamber;

a lower chamber beneath the rotor housing, the liquid being injected into the lower chamber;

an inlet check valve installed within the lower chamber to be opened and closed according to a change in pressure in the variable volume spaces, thereby sucking the fluid in the lower chamber to the space of the rotor housing;

an outlet check valve installed within the upper chamber to be opened and closed according to the change in pressure in the variable volume spaces, thereby discharging the fluid in the space of the rotor housing to the upper chamber; and

an introduction passage connecting the inlet port of the upper chamber to the lower chamber.
The pump according to claim 1, further comprising:

an upper cover tightly installed on an upper surface of the rotor housing, and having a discharge port opened and closed by the operation of the outlet check valve; and

a lower cover tightly installed on a lower surface of the rotor housing, and having a suction port opened and closed by the operation of the inlet check valve.
The pump according to claim 2, wherein the introduction passage is defined by passage holes that are respectively formed through a lower surface of the upper chamber, the upper cover, the rotor housing, the lower cover, and an upper surface of the lower chamber, and the passage holes are vertically formed at the same position.
The pump according to claim 2, further comprising a circulation passage connecting the upper chamber to the lower chamber.
The pump according to claim 4, wherein the circulation passage is defined by passage holes that are respectively formed through a lower surface of the upper chamber, the upper cover, the rotor housing, the lower cover, and an upper surface of the lower chamber, and the passage holes are vertically formed at the same position.
The pump according to claim 4, further comprising a floating valve installed within the lower chamber to open and close the circulation passage.
The pump according to claim 6, further comprising a floating valve housing having a passage formed vertically therethrough for communication between the circulation passage and a lower space of the lower chamber, and having an elevation space defined in the middle of the passage for installation of the floating valve therein so that the elevation space has a larger cross-sectional area than the passage.
The pump according to claim 7, wherein a lower portion of the floating valve housing is submerged in the liquid injected into the lower chamber, and the liquid is introduced into the passage of the floating valve housing so that the floating valve is floated.
The pump according to claim 7, wherein an upper inlet of the elevation space is blocked by the floating valve so that the passage is closed when the floating valve is fully moved up, whereas a lower outlet of the elevation space is blocked by the floating valve when the floating valve is fully moved down.
The pump according to claim 7, wherein the inlet check valve is installed on an upper surface of the lower chamber, and the lower chamber has a basic level of liquid under which an inlet of a valve housing of the inlet check valve is submerged in the liquid in a state in which the pump is not operated.
The pump according to claim 10, wherein the floating valve is installed such that it blocks an upper inlet of the elevation space in the basic level of liquid to close the circulation passage.
The pump according to claim 1, wherein the outlet check valve is installed on a bottom surface of the upper chamber, and outlets are formed at all of an upper surface and both sides of a valve housing of the outlet check valve.
The pump according to claim 7, wherein the floating valve consists of an upper hemisphere, a lower hemisphere, and a cylindrical portion connecting the upper hemisphere to the lower hemisphere.
The pump according to claim 13, wherein the cylindrical portion has guide rings formed at upper and lower portions thereof to slide along an inner peripheral surface of the elevation space.
The pump according to claim 13, wherein the cylindrical portion has a plurality of guide protrusions formed at upper and lower portions thereof to slide along an inner peripheral surface of the elevation space.