JP2809649B2 - Rotary pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an impeller formed by projecting a plurality of flexible blade members on the outer periphery of a cylindrical member in a pump chamber having a cylindrical inner peripheral surface. The present invention relates to improvement of a rotary pump provided.

[Conventional technology]

In general, a rotary pump of a flexible impeller includes a pump chamber having a cylindrical inner peripheral surface and a rubber impeller disposed in the pump chamber. The impeller is disposed concentrically with respect to the pump chamber, and a holding cam for causing the impeller to perform a pumping operation is provided between the discharge port and the suction port in the impeller rotation direction of the pump chamber. . That is, in this type of rotary pump, with the rotation of the impeller, the handled liquid sucked and sandwiched in the water chamber formed between the adjacent flexible blade members at the suction port, the flexible liquid at the discharge port. The blade member is bent by the pressing cam and the volume of the water chamber is reduced, so that the blade member is discharged to the discharge port, thereby performing a pump action.

However, the conventional rotary pump as described above requires the provision of a separate presser cam that requires special cutting in the pump chamber, so that the structure is not only complicated and heavy, but also the manufacturing cost is increased. Had the drawback of rising. In order to solve the above-mentioned problem, a rotary pump that does not require a holding cam (hereinafter referred to as a rotary pump without a cam or simply a rotary pump) has been provided. Hereinafter, this type of camless rotary pump will be described with reference to FIG.

7, the main components of the rotary pump 1 are a pump chamber 16 having a cylindrical inner peripheral surface having a suction port 12 and a discharge port 14 formed in a casing 10, and a plurality of pump chambers 16 (FIG. In the illustrated example, nine) flexible blade members 18-1 to 18-
9 is provided with an impeller 20, and the eccentric arrangement is such that the axis of the impeller 20 is shifted upward by a distance L with respect to the axis of the pump chamber. In such a configuration, when the flexible blade members 18-1 and 18-2 are positioned at the suction port 12 with the rotation of the impeller 20 at the time of the pump operation, the movable blade members 18-1 and 18- The trapped handling liquid sucked into the water chamber 22-1 whose volume is expanded by the extension of the liquid 2 at the discharge port 14 corresponds to the flexible blade member (corresponding to 18-7, 18-8 in the figure). Is bent and the volume in the water chamber (corresponding to 22-7 in the figure) is reduced, so that the water is discharged into the discharge pipe 14 and such a pumping action is performed by another flexible blade member 18. -3 to 18-9 are also performed continuously. As described above, according to this kind of camless rotary pump, since the pressing cam conventionally required is not required, the special cutting of the pressing cam is not required, and the structure is simple and lightweight, so that the product can be manufactured easily. Costs are reduced.

[Problems to be solved by the invention]

However, the conventional camless rotary pump as described above basically has the following drawbacks.

That is, in the process of sandwiching the handling liquid in the water chamber 22, at least three flexible blade members 18-1, 18-2, 18-3
Are in the process of elongation and therefore at least two water chambers 22-1, 22
In the water chamber 22-2, the flexible blade member 18-2 is connected to the inner peripheral surface 16a of the pump chamber 16 and the suction port 12-2.
Immediately after passing through the lower end portion of the connection edge with the pressure, the pressure in the water chamber 22-2 sharply drops to negative pressure. FIG. 5 shows, for convenience of explanation, the rotation angles when the temporarily specified water chamber 22-1 passes near the lower end portion of the connection edge of the suction port 12 and the discharge port 14 by 0 ° and 180 °, respectively. The water chamber 22-1 in
The pressure change in this type of camless rotary pump 10 is represented by a two-dot chain line curve I.
Is represented by The curve II will be described later.

For this reason, in the conventional camless rotary pump, there is a fundamental disadvantage that air bubbles are generated in the water chamber due to the negative pressure due to the rapid pressure drop in the water chamber, which causes a so-called cavitation phenomenon. I was doing it. This lowers the pump efficiency, and at the same time, generates a large number of continuous plosive sounds called cavitation noise accompanying the generation and disappearance of bubbles. Incidentally, FIG. 6 shows the QH characteristic (curve III) of the conventional camless rotary pump corresponding to curve I in FIG. 5 and the rotation corresponding to curve II (curve of the rotary pump according to the present invention described later). This is a comparison between the QH characteristics (curve IV) of the pump.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rotary pump capable of effectively reducing noise without causing a decrease in pump efficiency, particularly QH characteristics, by avoiding the occurrence of cavitation in a camless rotary pump. To provide.

[Means for solving the problem]

In order to achieve the above object, a rotary pump according to the present invention has a plurality of flexible blade members protruding from the outer periphery of a cylindrical member in a pump chamber having a cylindrical inner peripheral surface having a suction port and a discharge port. A rotary pump having an impeller formed eccentrically with respect to the pump chamber, extending from a connection portion between the inner peripheral surface and the suction port toward an impeller rotation direction on an inner peripheral surface of the pump chamber. A conductive groove having a predetermined length.

In this case, more preferably, one or more conductive grooves are provided in the circumferential direction near the center in the width direction of the circumferential surface of the pump chamber, or one or more conductive grooves are provided in the circumferential surface of the pump chamber inclined with respect to the circumferential direction. .

[Action]

When a negative pressure is generated in the water chamber through the flexible blade member passing through the connection portion between the inner peripheral surface and the suction port on the peripheral surface of the pump chamber, the handled liquid flows into the water chamber from the suction port through the conduction groove. However, an operation is performed such that the negative pressure disappears and cavitation is prevented from occurring, so that the pump efficiency does not decrease and the noise is effectively reduced.

〔Example〕

Next, an embodiment of the rotary pump according to the present invention will be described in detail with reference to the accompanying drawings. For convenience of description, the same components as those of the conventional structure shown in FIG. 7 are denoted by the same reference numerals, and detailed description thereof will be omitted.

1, the rotary pump 2 according to the present invention has basically the same structure as the conventional camless rotary pump shown in FIG. That is, the main configuration of the rotary pump 2 is that the suction port 12 and the discharge port 14
And a plurality of (in the illustrated example, nine) flexible blade members 18 on the outer periphery of the cylindrical member.
-1 to 18-9 projecting from the axis of the pump chamber 16 with respect to the axis of the pump chamber 16 in the upward direction in FIG. 6 of
% Of distance). The outer diameter of the impeller 20 is usually about 15% larger than the inner diameter of the pump chamber 16. During the operation of the pump, the rotation of the impeller 20 causes the flexible blade member 18 to rotate.
-1, 18-2 (temporarily specified for the sake of explanation) is located in the suction port 12, the water chamber 22-1 whose volume is expanded by the expansion of the flexible blade members 18-1, 18-2. The flexible blade member (corresponding to 18-7, 18-8 in the figure) is bent at the discharge port 14 by the handling liquid sucked and inserted into the water chamber, and the water chamber (corresponding to 22-7 in the figure) is bent. Is discharged into the discharge port 14 by reducing the volume of the inside of the flexible blade member 18-3 to 18-9.

However, in the rotary pump 2 of the present invention, the inner peripheral surface 16a of the pump chamber 16 is provided on the inner peripheral surface 16a of the pump chamber 16 from the connection edge portion between the inner peripheral surface 16a and the suction port 12 in the rotational direction of the impeller 20 (the direction of the arrow in the drawing). A conductive groove 30 having a predetermined length is formed to extend. As shown in FIG. 2, the conduction groove 30 extends in the circumferential direction near the center in the width direction of the inner peripheral surface 16a, and the blade member 18-3 is rotated at the rotational position of the impeller 20 as illustrated. It is preferable to extend to the vicinity of the portion slidingly contacting 16a.

It should be noted that since it is a known structure,
Covers (not shown) are attached to both side surfaces (the side facing the paper surface of FIG. 1 and the front side) of FIG. 10 and are appropriately fixed with small screws to make the casing 10 liquid-tight. Both side surfaces of the impeller 20 are slidably and liquid-tightly rotatable on the side surfaces. Further, one end of a drive shaft 32 fixedly fitted to the center of the impeller is projected out of the casing 10 (in a direction perpendicular to the paper surface of FIG. 1) via a seal member attached to the cover, and the shaft is A driving body (not shown) such as an electric motor is connected to the end.

In the rotary pump 2 of the present invention having such a configuration, the impeller 20 is rotated, and the flexible
When -2 passes through the connection portion of the suction port 12 on the peripheral surface 16a of the pump chamber, the pressure in the water chamber 22-2 suddenly decreases to a negative pressure. Flows into the water chamber 22-2 through the air passage, and acts so as to eliminate the negative pressure. Therefore, the pressure drop in the water chamber 22-2 is slightly suppressed, and the occurrence of cavitation is avoided. It is needless to say that the inflow of the handling liquid via the passageway 30 is performed while the volume of the water chamber 22-2 is expanded with the rotation of the impeller 20.

The previously described curve II shown by the solid line in FIG.
FIG. 7 shows the pressure change in the water chamber of the rotary pump of the present invention in comparison with curve I of the conventional camless rotary pump shown in FIG. 7, and as is apparent from the figure, according to the present invention, As compared with the above, the pressure drop in the water chamber is slightly suppressed, and at the same time, the volumetric efficiency is increased and the discharge pressure is increased. Therefore, the sixth
As clearly shown in the figure, the QH characteristic of the rotary pump of the present invention shown by curve IV is greatly improved compared to that of the conventional camless rotary pump shown by curve III. Moreover, in the rotary pump of the present invention, no cavitation is generated, so that a low-noise operation is of course achieved.

As described above, according to the present invention, the rotary pump is configured in a cam-less system, and at the same time, the occurrence of cavitation is avoided, so that a rotary pump with high pump efficiency and low noise can be manufactured easily and at low cost. Can be provided.

Next, FIGS. 3 and 4 show an embodiment in which the conduction grooves are different from each other. Each of the conductive grooves 34 shown in FIG. 3 includes three narrow conductive grooves 36 extending in the circumferential direction from the connection edge portion between the inner peripheral surface 16a of the pump chamber 16 and the suction port 12 toward the rotation direction of the impeller. -1,36-2,36-3. The conduction groove shown in FIG. 4 is a single groove extending from the right end of the connection edge portion between the inner peripheral surface 16a of the pump chamber 16 and the suction port 12 to the left in the circumferential direction toward the rotation direction of the impeller. In the inclined conductive groove 38, the extending end of the inclined conductive groove 38 is within the field line projected from the left end of the connection edge portion to the inner peripheral surface 16a.

According to the conduction groove having such a configuration, in the case of the conduction groove 34, each of the narrow width conduction grooves 36-1 to 36-3 has the conduction groove 30.
The sliding contact ends of the flexible blade members 18-1 to 18-9 sliding on the inner peripheral surface 16a are smaller than the narrow conductive grooves 36-1.
Or the amount of deformation (deforming so as to bulge toward the groove bottom) when straddling over 36-3 is small, so that the wear of this portion is slight and the worn portion is also the flexible blade member 18-.
1 to 18-9 dispersed in the width direction, and
In the case of (1), since the groove width is as wide as that of the conductive groove 30, the amount of deformation when the sliding contact end straddles the inclined conductive groove 38 is large.
The former 34 and the latter 38 tend to be uniform in the width direction of 18-9, and both the former 34 and the latter 38 have the effect of extending the service life of the impeller 20. High peripheral speed (around 15m / s)
In order to instantaneously, uniformly, and effectively flow the handling liquid into the chambers of the water chambers 22-1 to 22-9 which rotate and move, the conduction groove 34 having a plurality of conduction grooves or the handling liquid It is obvious that the inclined conducting groove 38 in which the inflow portion moves in the width direction of the water chambers 22-1 to 22-9 with rotation is excellent.

Although the present invention has been described in connection with the preferred embodiments, it is needless to say that many design changes can be made without departing from the spirit of the present invention.

〔effect〕

As described above, in the rotary pump according to the present invention, a rotary pump in which a flexible impeller is eccentrically arranged in a pump chamber having a cylindrical inner peripheral surface, that is, a rotary pump without a cam, Since it is configured to provide a conducting path for flowing the handling liquid from the suction port to the located water chamber, it is possible to eliminate the negative pressure that has conventionally occurred in the water chamber, and to reduce the cavitation caused by the negative pressure. Can be avoided. Therefore, it is possible to provide a rotary pump that is simple in structure, easy to manufacture, and excellent in pump efficiency and low in noise.

[Brief description of the drawings]

1 is a longitudinal sectional view showing an embodiment of the rotary pump according to the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIGS. 3 and 4 are respectively shown in FIG. FIG. 5 is a sectional view corresponding to FIG. 2 in another embodiment different from the conduction groove, FIG. 5 is a θ-H diagram showing a pressure change in a water chamber in the rotary pump according to the present invention and a conventional rotary pump, and FIG. Q represents the pump characteristics of the rotary pump according to the present invention and the conventional rotary pump.
FIG. 7 is a vertical sectional view showing a conventional rotary pump. 2 ... Rotary pump, 12 ... Suction port 14, ... Discharge port, 16 ... Pump chamber 16a ... Inner peripheral surface 18-1, 18-9 ... Flexible blade member 20 ... Impeller 22-1, ... 22-9 ... water chamber 30 ... conduction groove, 34 ... conduction groove 36-1, ... 36-3 ... narrow conduction groove 38 ... inclined conduction groove

Claims (3)

(57) [Claims] An impeller formed by projecting a plurality of flexible blade members on the outer periphery of a cylindrical member inside a pump chamber having a cylindrical inner peripheral surface having a suction port and a discharge port is eccentric to the pump chamber. In the rotary pump, the conductive groove having a predetermined length extending in the impeller rotation direction from the connection edge portion between the inner peripheral surface and the suction port is formed in the inner peripheral surface of the pump chamber. A rotary pump characterized by the following. 2. The rotary pump according to claim 1, wherein one or more conductive grooves are circumferentially recessed in the vicinity of the center in the width direction of the peripheral surface of the pump chamber. 3. The rotary pump according to claim 1, wherein one or more conductive grooves are formed in the circumferential surface of the pump chamber so as to be inclined with respect to the circumferential direction.