JPH1130194A - Balance disc structure of centrifugal pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent fine powder from being generated as well as to achieve the stable operation of a balance disc structure by constituting an orifice part without contact of a fixed disc and the balance disc. SOLUTION: A balance disc structure is provided with a balance disc 12 to be rotated together with an impeller 2, and a fixed disc 14 provided between the balance disc 12 and the impeller 2, pressurizing fluid on the impeller back surface is made to escape from a clearance A between the balance disc 12 and the fixed disc 14 to the back surface of the balance disc 12, and thrust force F to act on the impeller is balanced by pressure to act on the balance disc 12. A bearing 3a for a rotor 5 for supporting the impeller 2 is directly attached to the fixed disc 14 fixed to a pump main body 6, and the balance disc 12 is attached to the rotor 5. Moreover, the bearing is constituted of an angular contact bearing, and the supporting point (a) is positioned near the balance disc attaching part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a centrifugal pump, and more particularly, to a balance disc structure of a centrifugal pump.

[0002]

2. Description of the Related Art A centrifugal pump is a pump that rotates an impeller at a high speed in a casing and gives energy to a liquid. FIG. 2 is an overall configuration diagram of such a centrifugal pump. An inducer 1 for introducing a liquid, an impeller 2 for pressurizing the liquid, bearings 3a and 3b for supporting the rotation of the impeller, and
The motor 4 rotates the rotor 5 at a high speed (for example, about 40,000 rpm). The rotating force is transmitted to the impeller 2, and the rotation of the impeller 2 gives energy to the liquid. Pressure.

FIG. 3 is a partially enlarged view of FIG. In the centrifugal pump described above, the impeller 2
A large thrust force F (leftward in the figure) is generated on the back surface of the motor. To support this thrust force F, a so-called balance disk structure (also referred to as a balance piston mechanism) has been conventionally used. As shown in FIG. 3, the balance disk structure includes, as shown in FIG. 3, a flow path 7 through which a pressurized liquid flows on the back surface (right side surface in the figure) of the impeller 2, a balance disk 8 which rotates together with the impeller 2, and a front surface opposed thereto. The pressure in the flow path 7 is released from the gap A between the balance disk 8 and the fixed disk 9 to the back surface of the balance disk 8, whereby the thrust force f (see FIG. To the right) to adjust the position of the balance disk 8 so that the two thrust forces F and f coincide with each other to balance the thrust forces.

The position of the balance disk 8 is adjusted by a gap A shown in FIG. That is, the thrust forces F, f
When the thrust force F increases, the balance disk 8 moves slightly to the left, and a gap A suitable for high-speed rotation is formed. Is closed, the pressure acting on the front face of the balance disk increases, and as a result, the thrust force f increases and the thrust forces F and f are balanced. Conversely, when the thrust force F decreases, the balance disk 8 slightly moves to the right, the gap A widens, and the pressure acting on the front of the balance disk decreases. As a result, the thrust force f decreases and the thrust force F decreases. , F are balanced. Therefore, with such a balance disk structure, the thrust force acting on the bearings 3a, 3b can be made almost zero.

[0005]

As shown in FIG. 3,
In the conventional structure, the counter disk (fixed disk 9) that forms the orifice (gap A) with the balance disk 8 is separately attached to the bearing support member (pump body 6), and the support point a of the rotor shaft 5 is Was far away from

Due to this structure, in the conventional balance disk structure, the occurrence of a parallelism error and a mounting error between the fixed disk 9 and the balance disk 8 is inevitable. The balance disk 8 and the fixed disk 9 may come into contact with each other at the orifice portion (gap A) due to the influence of the shaft runout, which may cause unstable operation of the balance disk portion and generation of fine powder. Was.

The present invention has been made to solve such a problem. That is, an object of the present invention is to provide a centrifugal pump that can form an orifice portion without contact between a fixed disk and a balance disk, thereby stabilizing the operation of the balance disk structure and, at the same time, preventing the generation of fine powder and the like. Another object of the present invention is to provide a balance disk structure.

[0008]

According to the present invention, there is provided a balance disk which rotates together with an impeller, and a fixed disk provided between the balance disk and the impeller. In a balance disk structure of a centrifugal pump in which the pressurized fluid on the back surface is released to the back surface of the balance disk and thereby the thrust force F acting on the impeller is balanced by the pressure acting on the balance disk, the impeller is fixed to the fixed disk fixed to the pump body. A balance disk structure of a centrifugal pump characterized by directly mounting a rotor bearing for supporting the rotor and mounting a balance disk to the rotor.

According to the configuration of the present invention described above, the fixed disk is fixed to the pump body, the bearing for the rotor that supports the impeller is directly mounted on the fixed disk, and the balance disk is mounted on the rotor. By mounting the bearing directly on the balance disk, the deflection of the balance disk and the fixed disk during rotation can be minimized. That is, in the conventional structure, since the pump main body 6 is interposed between both the fixed disk 9 and the balance disk 8, the occurrence of the respective parallelism error and the mounting error with respect to the pump main body 6 is unavoidable. In the configuration of the present invention, the bearing is directly mounted on the fixed disk without the intervention of the pump body, and the balance disk is positioned via the bearing and the rotor. The occurrence of the respective parallelism errors and mounting errors with respect to the main body 6 can be avoided, and the rotational deflection of the balance disk with respect to the fixed disk can be greatly reduced. The bearing is preloaded with a disc spring or the like to eliminate the bearing gap. Therefore, since the parallelism between the balance disk and the other party (fixed disk) can be ensured with high accuracy, contact between the balance disk and the other party can be prevented.

According to a preferred embodiment of the present invention, the bearing for the rotor is constituted by an angular contact bearing, and its supporting point is positioned near the balance disk mounting portion. With this configuration, it is possible to reduce the axial displacement in the vicinity of the balance disk mounting portion, and to reduce the deflection of the shaft of the balance disk portion.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In addition, the same reference numerals are given to the common parts in the respective drawings, and the duplicate description will be omitted. FIG. 1 is a configuration diagram showing a balance disk structure of a centrifugal pump according to the present invention. In this figure, the balance disk structure of the present invention includes a balance disk 12 that rotates together with the impeller 2, and a fixed disk 14 provided between the balance disk 12 and the impeller 2, and a gap between the balance disk 14 and the fixed disk 12. A allows the pressurized fluid on the back of the impeller to escape to the back of the balance disk 14, thereby generating a thrust force f acting on the impeller 2 and a thrust force f acting on the impeller 2 due to the pressure acting on the front of the balance disk. This structure is the same as the conventional balance disk structure shown in FIG.

In the balance disk structure of the present invention, FIG.
As shown in FIG. 2, a bearing 3a for the rotor 5 supporting the impeller 2 is directly attached to a fixed disk 14 fixed to the pump body 6, and the balance disk 12 is mounted on the rotor 5.
Is directly attached. That is, a hollow cylindrical portion 14a is provided on the fixed disk 14, its outer peripheral surface 14b is fitted into the pump body 6, and the bearing 3a is fitted into its inner peripheral surface 14c. With this structure, the fixed disk 14
Of the outer peripheral surface 14b and the inner peripheral surface 14c, and the facing surface 14d (constituting the gap A) with the balance disk can be processed with high accuracy using a lathe or the like, and the concentricity of the outer peripheral surface 14b and the inner peripheral surface 14c The perpendicularity of the facing surface 14d to the axis can be kept extremely high.

Accordingly, in the conventional structure, since the pump body 6 is interposed between both the fixed disk 9 and the balance disk 8, it is inevitable that a parallelism error and a mounting error with respect to the pump body 6 occur. However, in the configuration of the present invention described above, the bearing 3a is directly attached to the fixed disk 14 without the pump body 6 interposed therebetween.
Since the balance disk 12 is positioned via the rotor 5 and the rotor 5, the occurrence of a parallelism error and an attachment error with respect to the pump body 6 can be avoided, and the rotational vibration of the balance disk 12 with respect to the fixed disk 14 is greatly reduced. Can be reduced. The bearing 3a is preloaded by a disc spring 15 to eliminate the bearing gap. Therefore, since the parallelism between the balance disk 12 and the counterpart (fixed disk 14) can be ensured with high accuracy, the contact between the balance disk 12 and the fixed disk 14 can be prevented.

Further, according to the present invention, as shown in FIG. 1, the bearing 3a for the rotor 5 is constituted by an angular contact bearing, and its support point a is positioned near the balance disk mounting portion. With this configuration, it is possible to reduce the axial displacement in the vicinity of the balance disk mounting portion, and further reduce the deflection of the shaft of the balance disk portion.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the spirit of the present invention.

[0016]

As described above, according to the balance disk structure of the centrifugal pump of the present invention, the orifice portion can be formed without the fixed disk and the balance disk coming into contact with each other, thereby stably operating the balance disk structure. At the same time, it can prevent the generation of fine powder and the like.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a balance disk structure of a centrifugal pump according to the present invention.

FIG. 2 is an overall configuration diagram of a conventional centrifugal pump.

FIG. 3 is a partially enlarged view of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inducer 2 Impeller 3a, 3b Bearing 4 Electric motor 5 Rotor 6 Pump main body 7 Flow path 8 Balance disk 9 Fixed disk 12 Balance disk 14 Fixed disk 14a Hollow cylindrical part 14b Outer peripheral surface 14c Inner peripheral surface 14d Opposing surface 15 Disc spring

Claims (2)

[Claims] 1. A balance disk which rotates with an impeller, and a fixed disk provided between the balance disk and the impeller, and pressurized fluid on the back of the impeller is supplied to the back of the balance disk from a gap A between the balance disk and the fixed disk. In a balance disk structure of a centrifugal pump that balances the thrust force F acting on the impeller by the pressure acting on the balance disk, the bearing for the rotor that supports the impeller is directly attached to the fixed disk fixed to the pump body. And a balance disk attached to the rotor. 2. The bearing according to claim 1, wherein the bearing for the rotor is constituted by an angular contact bearing, and a support point a thereof is positioned near a balance disk mounting portion.
The balance disc structure of the centrifugal pump according to 1.