JP2001065484A - Multi-stage pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-stage pump capable of easily connecting pumps at the front and rear thereof with a reduced size and pressure loss. SOLUTION: In this multi-stage pump, an impeller 7 fixed to an input shaft 1 is formed so that a front shroud 10 is larger in diameter than a rear shroud 8, and delivery ports 17 and 22 are provided at the center of the front shroud 10 at a position where the delivery ports faces the front shroud 10 on the outer periphery of spiral casings 13 and 19 for storing a suction part 9 and the impeller 7 so as to form pump mechanisms 4 and 5. A plurality of the mechanisms 4 and 5 are disposed on the input shaft in parallel with each other, and the delivery port 17 of the pump mechanism 4 positioned at the front is communicated with the suction part 9 of the pump mechanism 5 positioned at the rear so as to form the multi-stage pump.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized multi-stage pump in which a plurality of pump mechanisms are connected in series to improve the discharge pressure.

[0002]

2. Description of the Related Art Several types of pumps have been conventionally used for pumping liquid, and centrifugal pumps are one of them. A centrifugal pump rotates an impeller incorporated in a pump chamber. The structure is such that liquid sucked from a suction portion provided at the center of the front surface of the pump chamber is discharged to the outer periphery of the impeller by centrifugal force generated by rotation of the impeller.

[0003]

As means for improving the discharge pressure and the pumping height by using the centrifugal pump as described above, a multistage pump in which a plurality of centrifugal pumps are connected in series is considered. However, since the conventional centrifugal pump has a structure in which the liquid is discharged to the outer periphery of the impeller, the process of connecting the discharge part of the pump located at the front part and the suction part of the pump located at the rear part is structurally performed. Complicated and difficult,
There is a problem that the shape of the whole multi-stage pump becomes large, and the connection portion becomes long and complicated, so that the pressure loss increases.

It is an object of the present invention to provide a multi-stage pump which can easily connect the front and rear pumps, is small in size, has low pressure loss, and can obtain a high head.

[0005]

According to a first aspect of the present invention, an impeller fixed to an input shaft is formed such that a front shroud has a larger diameter than a rear shroud. A suction mechanism is provided at the center of the front of the guide chamber for accommodating the impeller, and a swirl chamber and a discharge section are provided at a position facing the front shroud outside the outer periphery of the rear shroud to form a pump mechanism. A configuration is adopted in which a plurality of pump units are arranged on a shaft and the discharge unit of the pump mechanism located at the front is connected to the suction unit of the pump mechanism located at the rear.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

As shown, the input shaft 1 rotatably penetrates a cover 3 for closing a casing 2 in a watertight manner and a portion protruding outside the cover 3 is connected to a drive source.
Two pump mechanisms 4 and 5 are mounted side by side in a state of being separated by an intermediate guide wall 6 before and after a portion located inside the casing 2.

The impeller 7 of each of the pump mechanisms 4 and 5 has a disk-shaped rear shroud 8 fixed to the input shaft 1 and a disk shaped larger in diameter than the rear shroud 8 and has a suction portion 9 at the center. And a plurality of blades 11 provided between the rear shroud 8 and the front shroud 10. The blades 11 are provided over the entire length in the radial direction so as to reach the outer periphery from the suction portion 9 of the front shroud 10. The space between the opposing surfaces of the rear shroud 8 and the front shroud 10 forms a liquid passage.

A pump mechanism 4 located at a front portion rotatably accommodates an impeller 7 in a spiral chamber 13 of an annular guide 12 incorporated in a casing 2, and a front wall 14 provided in the casing 2 has a front shroud 10. The rear wall 15 of the guide 12 approaches and approaches the rear shroud 8,
A suction port 16 communicating with the suction section 9 at the center of the front wall 14
Is provided.

The guide 12 is provided with a discharge port 17 communicating with an annular spiral chamber 13 at a position outside the outer periphery of the rear shroud 8 and facing the front shroud 10 with the blades 11 interposed therebetween.

The front pump mechanism 4 sucks the liquid from the central suction part 9 by the rotation of the impeller 7 and sends it out to the outer peripheral side by centrifugal force due to the rotation. The guide 12 is fed in the axial direction opposite to the front shroud 10 and flows out to a discharge port 17 provided on the outer periphery of the guide 12.

The rear pump mechanism 5 rotatably stores the impeller 7 in a spiral chamber 19 of an annular guide 18 incorporated in the casing 2, and the intermediate guide wall 6 in the casing 2 is attached to the front shroud 10. The rear wall 20 of the guide 18 approaches and opposes the rear shroud 8,
A suction port 21 communicating with the suction section 9 is provided at the center of the intermediate guide wall 6.

The spiral chamber 19 of the guide 18 is located outside the outer periphery of the rear shroud 8 at a position facing the front shroud 10 with the blades 11 interposed therebetween or the guide 18.
Outlet 2 opening in cover 3 of casing 2 on the peripheral wall of
2 are provided.

The liquid flowing out of the discharge port 17 of the front pump mechanism 4 passes through a passage 23 formed between the rear wall 15 of the guide 12 and the intermediate guide wall 6 so as to flow radially inward. Then, the air is sucked into the rear pump mechanism 5 from the suction port 21 of the intermediate guide wall 6.

A front wall 14 is provided on the front side of the casing 2.
A suction passage 24 communicating with the suction port 16 is provided, and a discharge port 25 and a priming port 26 are provided at positions outside the two pump mechanisms 4 and 5 of the casing 2.
By injecting priming water into the casing 2 from
Although both pump mechanisms 4 and 5 are non-self-priming pumps, they can also be used as self-priming pumps.

Although two pump mechanisms 4 and 5 are arranged in series on the rotating shaft 1 in the illustrated example, the number of pump mechanisms can be further increased as necessary.

The multi-stage pump according to the present invention has the above-described structure, and the suction passage 24 is connected to the water source, and the pumping water is injected into the casing 2 so that the impellers 7 are immersed therein. When the rotating shaft 1 is rotated by the activation of the drive source, the impellers 7, 7 fixed to the rotating shaft 1 rotate integrally, and the front pump mechanism 4 generates a suction force by the rotation of the impeller 7. The liquid sucked into the suction section 9 from the suction port 16 is pressurized through the impeller 7, flows out of the spiral chamber 13 to the discharge port 17, and is sent to the rear pump mechanism 5, and the rear pump mechanism 5 After being pressurized again at 5, it flows out of the discharge port 25 of the casing 2, and the high pressure and high head of the liquid can be discharged by pressurization by both pump mechanisms 4 and 5.

As described above, the two pump mechanisms 4 and 5 discharge the liquid in the axial direction facing the front shroud 10 and the blade 11 by the rotation of the impeller 7.
The outer diameters of both pump mechanisms 4 and 5 can be made as small as possible, and the shape of the multi-stage pump can be made compact.

[0019]

As described above, according to the present invention, the impeller is formed such that the front shroud has a large diameter with respect to the rear shroud, and the suction portion is provided at the center of the front of the spiral chamber accommodating the impeller. A pump mechanism is formed by providing a discharge section on the side facing the front shroud on the outer periphery, and a plurality of the pump mechanisms are arranged on the input shaft, and the discharge section of the pump mechanism located at the front is located at the rear. Since the suction is conducted to the suction part of the mechanism, both pump mechanisms have a structure in which the liquid is discharged to the side facing the front shroud in the axial direction of the impeller, and the connection of both pump mechanisms is processed within the inner diameter of the spiral chamber, The connection structure can be simplified, the size of the multi-stage pump can be reduced by minimizing the outer diameter, and the high-pressure and high-head discharge can be realized by the multi-stage pump mechanism.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view of a multistage pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input shaft 2 Casing 4 Pump mechanism 5 Pump mechanism 6 Intermediate guide wall 7 Impeller 8 Rear shroud 9 Suction part 10 Front shroud 11 Blade 12 Guide 13 Swirling chamber 16 Suction port 17 Discharge port 18 Guide 19 Swirl chamber 21 Suction port 22 Spit Outlet 23 Passage 24 Suction passage 25 Discharge port

Claims (1)

[Claims] An impeller fixed to an input shaft is formed such that a front shroud has a large diameter with respect to a rear shroud.
A suction mechanism is provided at the center of the front of the guide chamber for accommodating the impeller, and a spiral chamber and a discharge part are provided at a position outside the outer periphery of the rear shroud and facing the front shroud to form a pump mechanism. A multi-stage pump in which a plurality of pumps are arranged side by side, and a discharge part of a pump mechanism located at a front part is connected to a suction part of a pump mechanism located at a rear part.