JPH0447437Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a multi-stage pump with opposed impeller arrangement, and more particularly to an improvement in the final stage discharge portion thereof.

BACKGROUND ART FIGS. 4 to 6 show a conventional impeller-opposed multistage pump, in which FIG. 4 is a cross-sectional view of the final stage discharge portion in the direction perpendicular to the axis, and FIG. 5 is a side view of its discharge flow path. , and FIG. 6 are longitudinal sectional views of the final stage discharge portion.

As shown in these figures, especially in FIG. 6, in a multistage pump with opposed impeller arrangement, the fluid flow of two groups of impellers 9, 9' arranged oppositely with the center stage section 8 in between is controlled. An upper long passage 5 and a lower long passage 6 are provided, and one impeller 9 is the final stage.
An upper discharge passage 3 and a lower discharge passage 4 are provided which connect the upper discharge volute 1 and the lower discharge volute 2 to the discharge port 7, respectively.

In a multi-stage pump, when the impellers are arranged opposite each other as described above, in other words, in order to reduce the horizontal thrust force in the axial direction, the single suction impellers of all stages are divided into two groups, and the impellers of these two groups are When a mechanism for arranging wheels facing each other is adopted, the part that partitions the space between the two groups of impellers 9, 9' facing each other is called a center stage part 8. In such a multi-stage pump with impellers arranged opposite each other, one of the two groups of impellers sandwiching the center stage section 8 is normally used to reduce the pressure resistance of the shaft seals located at both ends of the pump shaft. The impeller 9 is the final stage impeller.

Problems to be Solved by the Invention Incidentally, in the conventional multi-stage pump with opposed impeller arrangement as described above, as shown in FIG. Since the structure is such that the upper discharge passage 3 is provided on the outside and the lower long passage 6 is further provided on the radially outer side of this upper discharge passage 3, the distance from the pump axis of the lower long passage 6 is on the upper side. The height of the pump shaft is greater than the distance from the pump shaft center of the long passage 5, and as a result, a. There were problems in that the height of the pump became high and the weight of the c-pump casing became large.

The present invention was developed in order to solve the problems of the conventional technology.The height of the pump axis is lowered, and the upper long passage and lower long passage are formed at the same height and in the same shape. It is an object of the present invention to provide a multi-stage pump with opposed arrangement of impellers, which has an improved final stage discharge part so as to be easy to manufacture and to reduce the weight of the pump casing.

Means for Solving the Problems In order to solve the above problems, the present invention provides upper and lower long passages that connect the fluid flows of two groups of impellers arranged oppositely across the center stage part. In a multi-stage pump with opposed impeller arrangement, the pump has one impeller as the final stage, and has upper and lower discharge passages connecting the upper and lower discharge volutes of the final stage impeller to the discharge port, respectively. , an upper discharge passage is provided in the center stage portion in parallel with a lower discharge passage in the axial direction, and the upper long passage and the lower long passage are formed in the same shape and at the same height from the pump axis. .

Effect: According to the above means, by providing the upper long passage in the center stage section in parallel with the lower discharge passage in the axial direction, the height of the pump axis can be lowered, and the upper long passage and the lower long passage can be separated. They can be formed with the same height and the same shape, making manufacturing easier and reducing the weight of the pump casing.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 3.

FIG. 1 is a cross-sectional view in the direction perpendicular to the axis of the final stage discharge portion of an embodiment of the impeller array type multi-stage pump according to the present invention, FIG. 2 is a side view of the discharge passage, and FIG.
The figure is a longitudinal sectional view of the final stage discharge portion. In addition,
In FIGS. 1 to 3, the same parts as those shown in FIGS. 4 to 6 are given the same reference numerals, and redundant explanation will be omitted.

As shown in FIGS. 1 to 3, and especially FIG. The center stage section 8 is aligned with the path 4 in the axial direction.
As a result, the height of the pump axis is lower than that of the conventional pump, and the upper long passage 5 and the lower long passage 6 are formed at the same height and in the same shape. This simplifies manufacturing and reduces the weight of the pump casing.

As described above, according to the present invention, the upper discharge flow path 3 is provided using the center stage section 8, but this has become possible due to recent design improvements made by differential users.

In other words, the discharge flow path from the final stage impeller outlet to the discharge port also has a differential user function that converts the kinetic energy given to the discharge fluid by the final stage impeller into pressure energy. In order to obtain efficiency, the discharge flow path is planned to be approximately aligned with the center line of the discharge volute for the final stage impeller, so that the spout in the center stage part cannot be used.
However, due to recent improvements in the design of differential users,
Since it is now possible to guide the discharge flow path to the center stage portion and ensure the same diff user efficiency as before even if bending occurs in the axial direction, the upper discharge flow path 3 is formed in the center stage portion 8 as in the present invention. This has become possible.

Effects of the invention As described above, according to the invention, there is provided a long path on the upper and lower sides that connects the fluid flow of two groups of impellers arranged oppositely across the center stage part, and In a multi-stage pump with opposed impeller arrangement, the impeller is the final stage and has upper and lower discharge passages connecting the upper and lower discharge volutes of the final stage impeller to the discharge port, respectively,
By arranging the upper discharge passage and the lower discharge passage in the center stage section in the axial direction, the height of the pump axis can be lowered, and the upper long passage and the lower long passage can be made to have the same height and the same shape. The pump casing can be easily manufactured and has excellent effects such as reducing the weight of the pump casing.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view in the direction perpendicular to the axis of the final stage discharge portion of an embodiment of the impeller-opposing multistage pump according to the present invention, FIG. 2 is a side view of the discharge flow path, and FIG.
The figure is a longitudinal cross-sectional view of the final stage discharge portion, FIG. 4 is a cross-sectional view perpendicular to the axis of the final stage discharge portion showing a conventional impeller facing array type multi-stage pump, and FIG. 5 is a side view of its discharge flow path. FIG. 6 is a longitudinal sectional view of the final stage discharge portion. DESCRIPTION OF SYMBOLS 1... Upper discharge volute, 2... Lower discharge volute, 3... Upper discharge channel, 4... Lower discharge channel, 5... Upper long passage, 6... Lower longer passage, 7
...Discharge port, 8... Center stage section, 9... Final stage impeller, 9'... Impeller.

Claims (1)

[Scope of utility model registration request] It has upper and lower long passages that connect the fluid flow of two groups of impellers arranged opposite to each other across the center stage part, and one impeller is the final stage, and the upper side of this final stage impeller is provided. and a multi-stage impeller arrangement type pump having upper and lower discharge passages connecting the lower discharge volute to the discharge port, respectively, the upper discharge passage and the lower discharge passage in the center stage portion in the axial direction. 1. A multi-stage pump with opposed impeller arrangement, characterized in that the upper long passage and the lower long passage are arranged side by side and are formed in the same shape and at the same height from the pump axis.