JP2011122506A - Multistage turbine pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a multistage turbine pump preventing deflection of a bottom plate of a first stage intermediate casing without increasing the plate thickness of the first stage intermediate casing. <P>SOLUTION: In the multistage turbine pump, the interior of a cylindrical outer barrel 1 serves as a pump chamber 2, a plurality of impellers 3 and intermediate casings 4 are arranged in the pump chamber 2 while being stacked up in a multistage manner, a suction port casing 6 having a suction port is mounted to an opening portion at one end of the outer barrel 1 and a discharge port casing 8 having a discharge port is mounted to an opening portion at the other end, and the intermediate casings 4 are supported by the suction port casing 6 and the discharge port casing 8. A seat part 13 abutting against a suction port sided end face 12a of the first stage intermediate casing 4a on a suction port side is provided inside of the suction port casing 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a multistage turbine pump provided with a plurality of impellers.

  Conventionally, the inside of a cylindrical outer cylinder is used as a pump chamber, a plurality of impellers and intermediate casings are stacked in a multi-stage manner in the pump chamber, and a suction port having a suction port at one end opening of the outer cylinder A multi-stage turbine pump is known in which a casing is attached with a discharge port casing having a discharge port at the other end opening, and the intermediate casing is supported by the suction port casing and the discharge port casing (for example, Patent Document 1, 2).

  In the multi-stage turbine pump having such a structure, the fluid pressure of the sucked fluid is increased in each intermediate casing, and the pressure between the fluid pressure in the first-stage intermediate casing and the fluid pressure in the suction port on the suction port side. Due to the difference, a phenomenon occurs in which the bottom plate of the first stage intermediate casing is bent toward the suction port side. However, in the conventional multistage turbine pump disclosed in Patent Documents 1 and 2, the first pressure generated by the pressure difference between the fluid pressure in the first-stage intermediate casing on the suction port side and the fluid pressure in the suction port. No particular consideration is given to the bending of the bottom plate of the stage intermediate casing.

JP 2002-31073 A Japanese Utility Model Publication No.7-10076

As described above, in the multistage turbine pump disclosed in Patent Documents 1 and 2, the first pressure generated by the pressure difference between the fluid pressure in the first-stage intermediate casing on the suction port side and the fluid pressure in the suction port. Although no particular consideration is given to the bending of the bottom plate of the first stage intermediate casing, if the bottom plate of the first stage intermediate casing is bent each time due to repeated start and stop of the pump, the bottom plate and the impeller of the first stage intermediate casing There is a problem that the pump performance may be deteriorated, and there is a possibility of fatigue failure and lack of durability.
To prevent this, it is conceivable to increase the thickness of the first stage intermediate casing. However, if the thickness of the intermediate casing is increased, for example, when the intermediate casing is press-molded, a large press pressure is not required. Manufacturing equipment is required and material costs increase, resulting in increased costs and increased weight and difficulty in handling.

  An object of the present invention is to provide a multi-stage turbine pump that can prevent the bottom plate of the first stage intermediate casing from being bent without increasing the thickness of the first stage intermediate casing.

  In order to achieve the above object, according to the first aspect of the present invention, the inside of a cylindrical outer trunk is used as a pump chamber, and a plurality of impellers and intermediate casings are stacked in a multistage manner in the pump chamber. A suction port casing having a suction port at one end opening of the outer body and a discharge port casing having a discharge port at the other end opening are attached, and the intermediate casing is supported by the suction port casing and the discharge port casing. The multi-stage turbine pump is characterized in that a seat portion that abuts the suction port side end surface of the first stage intermediate casing on the suction port side is provided inside the suction port casing.

  A second aspect of the present invention is characterized in that the seat portion according to the first aspect is provided in a plurality radially from an inner surface to a central portion of the suction port casing.

  A third aspect of the invention is characterized in that a plurality of the seat portions according to the first aspect are provided in a circumferential direction.

  According to a fourth aspect of the present invention, the flow passage cross-sectional area around the seat portion according to any one of the first, second, and third aspects is larger than the flow passage cross-sectional area of the suction port. Features.

According to the multistage turbine pump of the first aspect, since the seat portion that contacts the suction port side end surface of the first stage intermediate casing on the suction port side is provided inside the suction port casing, the first stage intermediate Even if a large stress is applied to the bottom plate of the first stage intermediate casing due to the fluid pressure in the casing, the bottom plate of the first stage intermediate casing is brought into contact with the suction side end face of the bottom plate of the first stage intermediate casing. Bending can be prevented.
Thereby, it is not necessary to increase the thickness of the first stage intermediate casing, the cost can be reduced, and the weight can be reduced. In addition, since the bending of the bottom plate of the first stage intermediate casing is prevented, there is no change in the gap between the bottom plate of the first stage intermediate casing and the impeller even when the pump is repeatedly started and stopped. Can be maintained, and durability can be improved.
Also, since the bending of the bottom plate of the first stage intermediate casing is prevented, the capacity of the pump can be increased, that is, the diameter of the impeller can be increased, and the amount of pressure increase per stage of the intermediate casing can be increased. Even so, the strength of the bottom plate of the first stage intermediate casing can be maintained, and the number of stages of the intermediate casing can be reduced, so that the multistage turbine pump can be made compact.

  According to the multistage turbine pump of the second aspect, since the plurality of seats according to the first aspect are provided radially from the inner side surface of the suction inlet casing toward the central portion, the flow of the fluid to be sucked Without obstructing the path, it is possible to more effectively prevent the bottom plate of the first stage intermediate casing from being bent, and it is possible to further improve the strength of the bottom plate of the first stage intermediate casing.

  According to the multistage turbine pump of the third aspect, since the plurality of seat portions according to the first aspect are provided in the circumferential direction, the bending of the bottom plate of the first stage intermediate casing is performed in the entire circumferential direction. Can be prevented over.

  According to the multistage turbine pump of the fourth aspect, the flow passage cross-sectional area around the seat portion according to any one of the first, second, and third aspects is larger than the flow passage cross-sectional area of the suction port. Therefore, it is possible to reliably ensure the flow rate of the fluid to be sucked.

It is a vertical side view which shows one Example of the multistage turbine pump which concerns on this invention. It is a principal part enlarged view of FIG. FIG. 3 is a partially omitted bottom view of FIG. 2. It is a bottom view of the suction inlet casing shown in FIG. It is explanatory drawing which shows the other example of the seat part shown in FIG.

Hereinafter, an example for carrying out the multistage turbine pump concerning the present invention is explained in detail with reference to drawings.
1 is a longitudinal side view showing an embodiment of a multi-stage turbine pump according to the present invention, FIG. 2 is an enlarged view of a main part of FIG. 1, FIG. 3 is a partially omitted bottom view of FIG. 2, and FIG. FIG. 5 is an explanatory view showing another example of the seat portion shown in FIG. 1.

As shown in FIG. 1, the multistage turbine pump of this example uses a cylindrical outer body 1 as a pump chamber 2. In the pump chamber 2, a plurality of impellers 3 and intermediate casings 4 are stacked in a multistage manner. A suction port casing 6 having a suction port 5 is attached to one end opening of the outer body 1, and a discharge port casing 8 having a discharge port 7 is attached to the other end opening, and these suction port casing 6, discharge port casing 8, Thus, the intermediate casing 4 is sandwiched and fixed.
The suction port casing 6 and the discharge port casing 8 are fastened by bolts 9 and are fastened at 3 to 4 locations equally in the circumferential direction. The impeller 3 is fixed to the pump shaft 10 and is fixed to the drive shaft of the motor 11.

In the multi-stage turbine pump configured as described above, a seat portion 13 is provided on the inner side of the suction port casing 6 so as to contact the suction port side end surface 12a of the bottom plate 12 of the first stage intermediate casing 4a on the suction port side. The seat portion 13 is provided so as to protrude from the inner side surface of the wall portion 14 of the suction port casing 6 toward the suction port side end surface 12a of the bottom plate 12 of the first stage intermediate casing 4a. Is not particularly limited as long as the suction hole 15 provided in the bottom plate 12 of the first stage intermediate casing 4a is not blocked.
In this example, a plurality of seats 13 are provided radially from the inner surface of the suction port casing 6 toward the center, that is, the suction holes 15 provided in the bottom plate 12 of the first stage intermediate casing 4a. In this example, the flow path cross-sectional area around the seat portion 13 is larger than the flow path cross-sectional area of the suction port 5.
In addition, in the seat part 13, as shown in FIG. 5, as another example, a plurality of seat parts 13 can be provided in the circumferential direction inside the inlet casing 6.

In this example, a mechanical seal chamber 17 having a mechanical seal 16 for sealing a portion of the pump shaft 10 is provided between the pump chamber 2 and the motor 11. The mechanical seal chamber 17 is provided in contact with the outer surface of the wall portion 14 of the suction port casing 6, and the mechanical seal chamber 17 and the first-stage intermediate casing on the suction port side are provided on the wall portion 14 of the suction port casing 6. 4 a, the communication passage 18 for introducing fluid from the first stage intermediate casing 4 a to the mechanical seal chamber 17, the mechanical seal chamber 17 and the suction port casing 6 are communicated and accumulated in the mechanical seal chamber 17. A communication hole 19 for discharging gas is provided. This configuration is a known technique (Japanese Utility Model Publication No. 7-10076).
In this example, one of the plurality of seats 13 provided on the inner side of the above-described suction port casing 6 has a seat 13a, the above-described mechanical seal chamber 17 and the inside of the first-stage intermediate casing 4a on the suction port side. A communication path 18 is provided to communicate with each other.

  According to the multistage turbine pump of the present example configured as described above, the seat portion that is in contact with the suction port side end surface 12a of the bottom plate 12 of the first stage intermediate casing 4a on the suction port side is disposed inside the suction port casing 6. 13 is provided, even if a large stress is applied to the bottom plate 12 of the first stage intermediate casing 4a due to the fluid pressure in the first stage intermediate casing 4a, the suction side of the bottom plate 12 of the first stage intermediate casing 4a The seat 13 that contacts the end surface 12a prevents the bottom plate 12 of the first stage intermediate casing 4a from being bent.

  As a result, it is not necessary to increase the thickness of the first stage intermediate casing 4a, and the cost can be reduced and the weight can be reduced. Further, since the bending of the bottom plate 12 of the first stage intermediate casing 4a is prevented, the gap between the bottom plate 12 of the first stage intermediate casing 4a and the impeller 3 is changed even if the pump is repeatedly started and stopped. The pump performance can be maintained, and the durability can be improved.

  In addition, since the bending of the bottom plate 12 of the first stage intermediate casing 4a is prevented, the capacity of the pump can be increased, that is, the diameter of the impeller 3 can be increased. Even if the pressure increase amount increases, the strength of the bottom plate 12 of the first stage intermediate casing 4a can be maintained, and the number of stages of the intermediate casing 4 can be reduced, so that the multistage turbine pump can be made compact. .

Moreover, in this example, since the seat part 13 is provided with two or more radially from the inner surface of the suction inlet casing 6 toward the center part, without interfering with the flow path of the fluid to be sucked, the first stage intermediate casing The bending of the bottom plate 12 of 4a can be more effectively prevented, and the strength of the bottom plate 12 of the first stage intermediate casing 4a can be further improved. Moreover, since the flow path cross-sectional area around the seat portion 13 is larger than the flow path cross-sectional area of the suction port, the flow rate of the fluid to be sucked can be reliably ensured.
Further, as another example, since the seat portion 13 shown in FIG. 5 is provided in a plurality in the circumferential direction inside the suction inlet casing 6, the bending of the bottom plate 12 of the first stage intermediate casing 4a is caused over the entire circumferential direction. Can be prevented.

  Moreover, in this example, the mechanical seal chamber 17 and the inside of the first stage intermediate casing 4a on the suction port side are communicated with one seat portion 13a among the plurality of seat portions 13 provided inside the suction port casing 6. Since the communication path 18 is provided, the structure can be simplified.

DESCRIPTION OF SYMBOLS 1 Outer cylinder 2 Pump chamber 3 Impeller 4 Intermediate casing 4a First stage intermediate casing 5 Suction port 6 Suction port casing 7 Discharge port 8 Discharge port casing 9 Bolt 10 Pump shaft 11 Motor 12 Bottom plate 12a Suction port side end surface 13, 13a Seat portion 14 Wall portion 15 Suction hole 16 Mechanical seal 17 Mechanical seal chamber 18 Communication path 19 Communication hole

Claims (4)

The inside of the cylindrical outer cylinder is used as a pump chamber, and a plurality of impellers and intermediate casings are stacked in a multistage shape in the pump chamber, and a suction port casing having a suction port at one end opening of the outer cylinder, In a multistage turbine pump in which a discharge port casing having a discharge port is attached to the other end opening, and the intermediate casing is supported by the suction port casing and the discharge port casing,
A multi-stage turbine pump characterized in that a seat portion that abuts on the suction port side end surface of the first stage intermediate casing on the suction port side is provided inside the suction port casing.   2. The multi-stage turbine pump according to claim 1, wherein a plurality of the seat portions are radially provided from an inner surface of the suction port casing toward a center portion.   The multi-stage turbine pump according to claim 1, wherein a plurality of the seat portions are provided in a circumferential direction.   4. The multistage turbine pump according to claim 1, wherein a flow passage cross-sectional area around the seat portion is larger than a flow passage cross-sectional area of the suction port.

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