JPH02102389A - Rotary pump - Google Patents

Abstract

PURPOSE:To prevent a cavitation resulting from a negative pressure by providing a linking passage to pour the dealing liquid from a suction port to a water chamber at the suction port side, in a rotary pump in which flexible impellers are arranged eccentrically in a cylindrical pump chamber. CONSTITUTION:In a rotary pump composed by arranging eccentrically an impel ler 20 which is formed of plural projecting flexible vane members 18-1 to 18-9 in a pump chamber 16 whose inner surface is cylindrical, furnishing a suction port 12 and a discharge port 14, a specific length of linking groove 30 extending from the connection edge position to the rotation direction of the impeller 20 is provided in a recessed form. This linking groove 30 is extended to the circumferential direction near the center in the width direction of the inner surface 16a, and extended up to the position where the vane member 18-3 is slided to the inner surface 16a.

Description

[Detailed Description of the Invention] [Technical Field] The present invention provides a rotatable impeller formed by a plurality of flexible blade members protruding from the outer periphery of a cylindrical member in a pump chamber whose inner peripheral surface is cylindrical. Regarding improvements to the installed rotary pump.

[Conventional technology]

Generally, a rotary pump with a visible impeller consists of a pump chamber with a cylindrical inner peripheral surface and a rubber impeller disposed within the pump chamber.

The impeller is arranged concentrically with respect to the pump chamber, and a presser cam is provided between the discharge port and the suction port in the impeller rotation direction of the pump chamber for causing the impeller to perform a pumping action. . That is, in this type of rotary pump, as the impeller rotates, the handled liquid is sucked into the water chamber formed between the adjacent visible vane members at the suction port and held in the water chamber at the discharge port. The bending blade member is bent by the presser cam and the volume of the ice chamber is reduced to be discharged to the discharge port, thereby performing a pumping action.

However, the conventional rotary pumps described above require a separate presser cam that requires special cutting to be installed inside the pump chamber, which not only makes the structure complex and heavy; There was a drawback that manufacturing costs increased. Therefore,
In order to solve the above-mentioned difficulties, a rotary pump that does not require a presser cam (hereinafter referred to as a camless rotary pump or simply a rotary pump) has been provided. This type of camless rotary pump will be described below with reference to FIG.

In FIG. 7, the main components of the rotary pump 1 are: a pump chamber 16 with a cylindrical inner circumferential surface having a suction port 12 and a discharge port 14 bored in the casing 10; an impeller 20 on which visible blade members 18-1 to 18-9 (9 in the illustrated example) are protruded, and the axis of the impeller 20 is shifted upward by a distance from the axis of the pump chamber. placed eccentrically. In such a configuration, during pump operation, when the flexible vane member 181.18-2 is located at the suction port 12 as the impeller 20 rotates, the visible vane member 18-1
．． Water chamber 22- whose volume is expanded by expansion of 18-2
1, the liquid to be handled is sucked into the visible vane member (18-7.18 in the figure) at the discharge port 14.
-8) is bent and the volume inside the water chamber (corresponding to 22-7 in the figure) is reduced,
It is discharged into the discharge pipe 14, and such a pumping action is continuously performed on the other visible vane members 18-3 to 18-9. In this way, this type of camless rotary pump does not require the presser cam that was conventionally required, so there is no need for special cutting of the presser cam, and the structure is simple and lightweight, so the product can be improved. Costs are reduced.

[Problem 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 handled liquid into the water chamber 22, at least three visible blade members 18-1, 18-2
．． 18-3 is in the process of extension and therefore at least two water chambers 22-1.22-2 are in the process of expansion, so that the water chamber 2
In 2-2, the visible vane member 18-2 is located in the pump chamber 16.
Immediately after passing the lower end of the connection edge between the inner circumferential surface 16a and the suction port 12, the pressure inside the water chamber 22-2 suddenly decreases to negative pressure.

For convenience of explanation, FIG. 5 shows the rotation angles of 0'' and 180 degrees when the temporarily specified water chamber 22-1 passes near the lower end of the connecting edge of the suction port 12 and the discharge port 14, respectively.
The pressure change in the camless rotary pump 10 of this type is represented by a two-dot chain curve (2). Note that the curve (■) will be described later.

For this reason, conventional camless rotary pumps have the fundamental drawback that air bubbles are generated in the water chamber due to the negative pressure caused by the sudden pressure drop in the water chamber, resulting in the so-called cavitation phenomenon. It was something that was done. This reduces pump efficiency and at the same time
This generates a large number of continuous burst sounds called so-called cavitation noises due to the generation and disappearance of bubbles. Incidentally, FIG. 6 shows the Q-H characteristics (curve ■) of a conventional camless rotary pump corresponding to the curve ■ in FIG. Pump Q-H characteristics (Curve TV
).

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rotary pump that can effectively reduce noise without causing a decrease in pump efficiency (in particular, IH characteristics) by avoiding the occurrence of cavitation in a rotary pump without a cam. It's about doing.

[Means to solve the problem]

In order to achieve the above object, the rotary pump according to the present invention has a plurality of visible vanes protruding from the outer periphery of a cylindrical member in a pump chamber whose inner peripheral surface is cylindrical and has a suction port and a discharge port. In a rotary pump in which an impeller to be formed is arranged eccentrically with respect to the pump chamber, an inner circumferential surface of the pump chamber is provided with an impeller extending in the impeller rotation direction from a connecting edge portion between the inner circumferential surface and the suction port. It is characterized by having a conductive groove of a predetermined length recessed therein.

In this case, one or more conductive grooves are provided in the circumferential direction near the widthwise center of the circumferential surface of the pump chamber, or one or more conductive grooves are provided on the circumferential surface of the pump chamber at an angle with respect to the circumferential direction.
It is even more suitable.

[Effect]

When the visible vane member passes through a connection area between the inner circumferential surface and the suction port on the circumferential surface of the pump chamber and negative pressure is generated in the water chamber, the handled liquid flows from the suction port into the water chamber through the conduction groove. Since the negative pressure disappears and the occurrence of cavitation is avoided, pump efficiency does not decrease and noise is effectively reduced.

〔Example〕

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

In FIG. 1, a rotary pump 2 according to the present invention has basically the same structure as the conventional camless rotary pump shown in FIG. 7. That is, the main components of the rotary pump 2 are: a pump chamber 16 having a cylindrical inner circumferential surface and having a suction port 12 and a discharge port 14 bored in the casing 10; The impeller 20 is formed by protruding visible blade members 18-1 to 18-9 (9 blades), and the axis of the impeller 20 is directed upward in FIG. 1 with respect to the axis of the pump chamber 16. The impeller is eccentrically arranged and shifted by a distance L (usually a distance of about 6% of the outer diameter of the impeller). Note that the outer diameter of the impeller 20 is generally about 15% larger than the inner diameter of the pump chamber 16. During pump operation, when the flexible vane members 18-1 and 18-2 (temporarily specified for convenience of explanation) are located at the suction port 12 as the impeller 20 rotates, the flexible vane members 18-1 and 18-2 (temporarily specified for convenience of explanation) are located at the suction port 12. The handled liquid is sucked into the water chamber 22-1 whose volume is expanded by the expansion of the water chamber 22-2, and is then passed through the visible vane member (18-7, 18-8 in the figure) at the discharge port 14. The ice chamber (corresponding to 22-7 in the figure) is bent to reduce the volume in the ice chamber (corresponding to 22-7 in the figure), and the ice is discharged into the discharge port 14, and this pumping action is caused by the other visible vane members 18- 3 to 18-9
It is also done continuously.

However, in the rotary pump 2 of the present invention, the inner circumferential surface 16a of the pump chamber 16 has a connection between the inner circumferential surface 16a and the suction port 1.
A conductive groove 30 of a predetermined length is recessed and extends from the connecting edge portion with the impeller 20 in the direction of rotation of the impeller 20 (in the direction of the arrow in the figure). As shown in FIG. 2, the conduction groove 30 extends in the circumferential direction near the widthwise center of the inner circumferential surface 16a, and is connected to the inner circumferential surface of the blade member 18-3 at the rotational position of the impeller 20 shown in the figure. It is preferable to extend it to the vicinity of the part where it is in sliding contact with 16a.

Incidentally, since it is a well-known structure, it will be briefly described,
Covers (not shown) are attached to both sides of the gauging 10 (on the opposite side and the front side of the paper in FIG. Both sides of the impeller 20 can be slid and rotated in a fluid-tight manner on the inner side of the impeller 20. Further, one end of the drive shaft 32 fixedly fitted in the center of the impeller 20 is connected to the outside of the casing 10 (the first
The shaft protrudes in a direction perpendicular to the plane of the drawing, and a driving body (not shown) such as an electric motor is connected to the shaft end of the shaft.

In the rotary pump 2 of the present invention having such a configuration, the impeller 20 is rotated, and the flexible blade member 1 is rotated in the figure.
8-2 passes through the suction port 12 connection part on the pump chamber peripheral surface 16a, the pressure in the water chamber 22-2 rapidly decreases and becomes negative pressure, but at the same time, the handled liquid in the suction port 12 flows through the conduction groove. 30 into the water chamber 22-2 and acts to eliminate the negative pressure, the pressure drop within the water chamber 22-2 is suppressed to a small extent and cavitation is avoided. Note that the inflow of the handling liquid through the conduction path 30 is as follows:
Of course, while the volume inside the water chamber 22-2 is expanded as the impeller 20 rotates, the water is neutralized.

The above-mentioned curve ■ shown by a solid line in FIG. 5 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. As is clear from the figure, according to the present invention, compared to the conventional system, the pressure drop in the water chamber is slightly suppressed, and at the same time, the volumetric efficiency is increased, resulting in an increase in the discharge pressure. Therefore, as clearly shown in FIG. 6, which is also mentioned above, the Q-H characteristic of the rotary pump of the present invention, indicated by curve IV, is significantly greater than that of the conventional camless rotary pump, indicated by curve ■. will be improved. Moreover, in the rotary pump of the present invention,
Of course, since cavitation does not occur, low-noise operation is achieved.

As explained above, according to the present invention, the rotary pump is configured without a cam and at the same time, the occurrence of cavitation is avoided. Therefore, a rotary pump with high pump efficiency and low noise can be manufactured easily and at low cost. can be provided to

Next, FIGS. 3 and 4 show embodiments in which conductive grooves have different configurations. The conduction grooves 34, which are not shown in FIG. 3, are three narrow conduction grooves extending circumferentially from the connection edge between the inner circumferential surface 16a of the pump chamber 16 and the suction port 12 in the direction of rotation of the impeller. It is composed of 36-1.36-2°36-3. The conduction groove shown in FIG. 4 extends from the right end of the connecting edge between the inner circumferential surface 16a of the pump chamber 16 and the suction port 12 toward the rotation direction of the impeller and is inclined to the left with respect to the circumferential direction.
In the case of the inclined conductive groove 38, the extending end of the inclined conductive groove 38 is within the boundary line projected from the left end of the connection edge portion onto the inner circumferential surface 16a.

According to the conduction groove having such a configuration, in the case of the conduction groove 34, since each of the narrow conduction grooves 36-1 to 36-3 is narrower than the conduction groove 30, it is difficult to slide the inner peripheral surface 16a. The sliding contact ends of the moving visible blade members 18-1 to 18-9 straddle the narrow conduction grooves 36-1 to 36-3, the amount of deformation (deformation to bulge toward the groove bottom) is small; Therefore, the wear in this part becomes slight, and the wear parts are also dispersed in the width direction of the visible blade members 18-1 to 18-9. Since the sliding contact end is as wide as 18-1 to 18-9, the amount of deformation is large when the sliding contact end straddles the inclined conduction groove 38, but as a result, the parts that wear out tend to be uniform in the width direction of the visible blade members 18-1 to 18-9. Both the former 34 and the latter 38 have the effect of extending the service life of the impeller 20. Furthermore, in order to instantly, uniformly, and effectively flow the handled liquid into the water chambers 221 to 22-9, which rotate at a high circumferential speed (approximately 15 m/s), a plurality of conduction grooves are required. It is obvious that the conduction groove 34 or the inclined conduction groove 38 in which the portion into which the handled liquid flows moves in the width direction of the water chambers 221 to 22-9 as they rotate are superior.

Although the present invention has been described above with reference to preferred embodiments, it goes without saying that many design changes can be made to the present invention without departing from its spirit.

〔effect〕

As explained above, the rotary pump according to the present invention is a rotary pump in which a visible impeller is eccentrically arranged in a pump chamber whose inner peripheral surface is cylindrical, that is, a camless rotary pump, which is located on the suction port side. Since the structure is such that a conduit is provided for the handling liquid to flow into the ice chamber from the suction port,
The negative pressure that conventionally occurs in the ice chamber can be eliminated, and cavitation caused by this negative pressure can be effectively avoided. Therefore, it is possible to provide a rotary pump of simple S construction, easy manufacture, excellent pump efficiency, and low noise at a low cost.

[Brief explanation of the drawing]

FIG. 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 A-A in FIG. 1, and FIGS. 3 and 4 are respectively shown in FIG. FIG. 5 is a sectional view corresponding to FIG. 2 in an embodiment different from the conduction groove, and FIG. , FIG. 6 is a Q-H diagram showing the pump characteristics of the rotary pump according to the present invention and the conventional rotary pump, and FIG. 7 is a longitudinal sectional view showing the conventional rotary pump. 2...Rotary pump 12 ...Suction port 14...
Discharge port 16...Pump chamber 16a...Inner peripheral surface 18-1. ...18-9...Visible blade member 20...
・Impeller 22-1. ...22-9...Ice chamber 30...Conducting groove 34...Conducting groove 36-1
．． ...3G-3...Narrow conduction groove 38...Slanted conduction groove

Claims (3)

[Claims] (1) An impeller, which is formed by protruding a plurality of flexible blade members on the outer periphery of a cylindrical member, is placed eccentrically with respect to the pump chamber in a pump chamber whose inner peripheral surface is cylindrical and has a suction port and a discharge port. In the installed rotary pump, a conduction groove of a predetermined length is recessed in the inner peripheral surface of the pump chamber and extends from a connecting edge portion between the inner peripheral surface and the suction port in the impeller rotation direction. A rotary pump characterized by: (2) The rotary pump according to claim 1, wherein the conduction groove is formed by recessing one or more grooves in the circumferential direction near the widthwise center of the circumferential surface of the pump chamber. (3) The rotary pump according to claim 1, wherein the conduction groove is formed by forming one or more grooves on the circumferential surface of the pump chamber at an angle with respect to the circumferential direction.