JPH0579840B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sheet metal centrifugal pump, and in particular, it is capable of suppressing deformation of the liner portion of the casing when an external force is applied to the suction flange, and at the same time, The present invention relates to a sheet metal centrifugal pump that can also improve the pump's discharge performance.

[Conventional technology]

In general, a sheet metal centrifugal pump is known in which a single stainless steel plate or the like is deep-drawn using a press to form a casing shell having a suction port, and a suction flange is fixed to the suction port of the casing shell. .

This type of centrifugal pump tends to be weak in strength, and when an external force is applied to the suction flange, there is a risk that this external force will be directly transmitted to the casing shell, causing the liner portion to deform. When the liner part deforms, contact occurs between it and the impeller.
This contact may cause problems such as noise and pump overload, and may even lead to unexpected situations such as contact between the casing shell and the impeller, resulting in damage to the impeller.

Therefore, conventionally, a partition is provided inside the casing shell to separate the suction chamber and the pressure chamber, and
Attach a liner ring to the partition part of this partition body,
and employing a so-called flexible structure in a part of the casing shell extending outside the partition,
When the above external force is applied, this flexible structure deforms only a part of the casing shell and prevents this deformation from being directly transmitted to the casing shell. A structure has been proposed to prevent this from occurring.

[Problem to be solved by the invention]

However, with the above configuration, the structure is complicated, and when connecting the suction pipe to the suction flange, the suction pipe itself must be supported against the foundation with another member. There is a troubling problem.

In addition, a partition is placed inside the casing shell,
If a liner ring is attached to the partitioning portion of the partitioning body, there is a problem in that excess material protrudes into the suction flow path, increasing suction resistance loss and deteriorating the pump's discharge performance.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the problems of the above-mentioned conventional techniques, and to provide a simple structure.
Moreover, to provide a sheet metal centrifugal pump which can suppress the deformation of the liner part of the casing when an excessive external force is applied to the suction flange, and at the same time improve the discharge performance of the pump. There is a particular thing.

[Means to solve the problem]

In order to achieve the above object, the present invention integrally forms a casing shell by deep drawing a steel plate using a press, rotatably supports an impeller inside the casing shell, and a mouse of the impeller. In the sheet metal centrifugal pump, which has a suction port facing the casing shell, a cylindrical suction nozzle is extended to the suction port of the casing shell, and the tip of the suction nozzle is extended into the mouth of the impeller. It is characterized by this.

[Effect]

According to the present invention, the cylindrical suction nozzle is extended to the suction port of the casing shell, and the tip of this suction nozzle is extended into the mouth of the impeller, so that excessive external force is not applied to the suction flange. Even though
This external force passes through the casing shell and reaches the fixed flange side, but does not reach the suction nozzle directly. Therefore, the suction nozzle itself is unlikely to be deformed, and therefore the tip of the suction nozzle and the impeller Collisions with the mouse are avoided. At the same time, since the tip of the suction nozzle extends into the mouth of the impeller, nothing extraneous protrudes into the suction flow path, and fluid suction resistance loss can be suppressed to a low level.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a spiral pump casing made of sheet metal according to the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 indicates a casing shell of a centrifugal pump, and this casing shell 1 is formed by deep drawing a stainless steel plate or the like using a press. A fixed flange 2 is integrally formed at one end of the casing shell 1, and a suction port 3 is opened at the other end of the casing shell 1. This casing shell 1 is connected by a fixed flange 2 to a motor bracket (not shown) or the like.

A volute chamber A extending in the circumferential direction is formed in the center inside the casing shell 1, and the outer periphery of the volute chamber A is defined by an overhanging portion 1a. This overhanging portion 1a is formed by bulging the outer circumferential wall of the casing shell 1 outward in the radial direction, and the height of the overhang is determined by starting the overhang in the middle, as shown in FIG. The height increases continuously along the counterclockwise direction. Thereby, the flow passage cross-sectional area of the volute chamber A gradually increases in the direction of fluid flow.

An impeller 5 is provided inside the casing shell 1, and the impeller 5 is integrated with a boss 6.
This boss 6 is connected to the free end of the main shaft 7.
A shaft sealing device 8 is attached to the main shaft 7, and this shaft sealing device 8 is supported by a casing cover 9 fixed to the casing shell 1.

The wall on the suction side of the casing shell 1 has a shoulder 1b that projects outward to increase the rigidity, so that the cross section is approximately S.
The flange support portion 1c is formed in a letter shape, and furthermore, a substantially cylindrical flange support portion 1c is integrally formed at the tip of the wall portion on the suction side. A suction flange 10 formed by press as a separate member is connected to this flange support portion 1c, and a suction port 11 connected to the above-mentioned suction port 3 is opened in the center of the suction flange 10.

This suction flange 10 is formed with a sealing surface 12 for connecting a companion flange (not shown), and as is clear from FIG. A reinforcing flange 13 is fixed thereto. The suction flange 10 is provided with four bolt holes 14, and the reinforcing flange 13 is provided with four through holes aligned with the bolt holes 14, as is clear from FIG. 15 are drilled.

Further, according to this embodiment, the suction flange 1
A substantially cylindrical suction nozzle 20 that extends toward the impeller 5 is integrally formed on the peripheral edge of the suction port 11 of FIG. The suction nozzle 20 is formed to become thicker toward the impeller 5 side. The periphery of the tip 20a of the suction nozzle 20 is loosely fitted into the mouth 5a of the impeller 5, and at the loosely fitted intersection, the peripheries of the two overlap with an appropriate width in the axial direction. ing. Furthermore, a ring-shaped protrusion or deflector 21 extending in the circumferential direction and having a substantially L-shaped cross section is fixed to the outer peripheral portion of the suction nozzle 20 .

Further, as is clear from FIG. 2, one end of a discharge nozzle 25 is connected to the highest position 23 of the overhanging portion 1a of the casing shell 1, and a discharge flange 26 is connected to the other end of this discharge nozzle 25. ing. This discharge flange 26 is a strip-shaped support member 2.
7 to firmly support the fixed flange 2, and a discharge port 28 is opened in the center of the discharge flange 26. The structure of the discharge flange 26 itself is the same as that of the suction flange 10, so a description thereof will be omitted.

Next, the operation of the centrifugal pump according to this embodiment will be explained.

A main shaft 7 is connected to a drive motor (not shown), and when the main shaft 7 is rotated, the impeller 5 rotates integrally with the main shaft 7, and fluid is sucked from the suction port 3 through the suction nozzle 20. This sucked fluid passes through the inside of the impeller 5, is given a centrifugal force, and is discharged into the volute chamber A from its outer periphery. This discharged fluid flows inside the volute chamber A in the circumferential direction (second direction).
counterclockwise in the figure), passes through the discharge nozzle 25, and is discharged from the discharge port 28 of the discharge flange 26.

According to this embodiment, the suction nozzle 2
Since the inner surface of 0 is formed smoothly and no extra protrusions protrude therein, the fluid flowing through the suction nozzle 20 flows smoothly into the impeller 5, thereby reducing suction resistance loss of the fluid. can be kept to a minimum.

Further, a part of the fluid that passes through the inside of the impeller 5, is applied with centrifugal force, and is discharged from the outer circumference into the volute chamber A, is in the environment between the flange support part 1c and the suction nozzle 20. It flows back into the flow path B. However, since the deflector 21 is disposed there, the fluid flowing backward is directed between the tip 20a of the suction nozzle 20 and the mouth 5a, as shown by the arrow Y.
It is injected into the impeller 5 through the gap between the volute and the volute chamber A, where it is applied with a centrifugal force and is again discharged into the volute chamber A from its outer circumference. According to this, fluid leakage into the so-called annular flow path B is reduced, and therefore the discharge performance of the pump can be improved by about 5%.

Furthermore, according to this embodiment, even when an external force acts on the suction flange 10, this external force reaches the fixed flange 2 through the flange support part 1c of the casing shell 1, and does not directly affect the suction nozzle 20.
does not reach. Therefore, even if the suction flange 10 is deformed due to the action of an external force, the suction nozzle 20 is hardly deformed, and contact between the tip 20a of the suction nozzle 20 and the mouth 5a of the impeller 5 is reliably avoided. be able to.

In addition, a volute chamber A whose flow path area gradually increases in the circumferential direction is formed in the center of the casing shell 1, so the pump performance is extremely improved. Since the casing shell 1 is made to protrude outward and has a substantially S-shaped cross section, the rigidity of the casing shell 1 is greatly increased.

FIG. 3 shows another embodiment. A protrusion 30 is integrally formed in the middle of the outer peripheral wall of the suction nozzle 20, and the protrusion 30 extends in the circumferential direction and is formed to bulge outward in the radial direction. According to this, since the protrusion 30 functions in the same manner as the deflector 21 (FIG. 1) described above, fluid leakage into the so-called annular flow path B is reduced, and the discharge performance of the pump is improved to that of the conventional one. can be improved by comparing.

Moreover, FIG. 4 shows another embodiment. According to this, a liner ring 32 having a substantially linear cross section is provided on the outer periphery of the tip 20a of the suction nozzle 20.
is press-fitted, and the outer periphery of this liner ring 32 is loosely fitted into the mouth 5a of the impeller 5. This liner ring 32 constitutes a so-called partition portion that partitions the annular flow path B and the inside of the mouth 5a of the impeller 5. According to this, fluid leakage from the partition portion is significantly suppressed.

FIGS. 5 and 6 each show other embodiments. According to FIG. 5, a liner ring 33 having a substantially L-shaped cross section is press-fitted onto the outer periphery of the tip 20a of the suction nozzle 20, and according to FIG. 6, a liner ring 34 having a substantially U-shaped cross section is press-fitted onto the outer periphery of the tip 20a of the suction nozzle 20. In this way, fluid leakage from the so-called partitions is significantly suppressed, similar to what is shown in FIG.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a casing shell is integrally formed by deep drawing a steel plate using a press, and an impeller is rotatably supported inside the casing shell. In a sheet metal centrifugal pump with a mouth facing the suction port of the casing shell, a cylindrical suction nozzle extends into the suction port of the casing shell, and the tip of this suction nozzle extends into the mouth of the impeller. Because of this, even if an excessive external force is applied to the suction flange, the suction nozzle is unlikely to be deformed, and it is therefore possible to sufficiently avoid contact between the tip of the suction nozzle and the mouth of the impeller. , as no extra material protrudes into the suction flow path.
Fluid suction resistance loss can be suppressed to a low level, and the pump's discharge performance can be improved compared to conventional pumps.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing one embodiment of a sheet metal centrifugal pump casing according to the present invention, FIG. 2 is a front view of the same, and FIG. 3 is a longitudinal sectional view showing another embodiment.
4 to 6 are longitudinal cross-sectional views showing other embodiments. 1...Casing shell, 3...Suction port, 5...
...Impeller, 10...Suction flange, 20...Suction nozzle, 20a...Tip, 21, 30...Protrusion, 32, 33, 34...Liner ring.

Claims (1)

[Claims] 1. A casing shell is integrally formed by deep drawing a steel plate using a press, and an impeller is rotatably supported inside the casing shell, and the mouth of the impeller is attached to the casing shell. In a sheet metal centrifugal pump facing the suction port, a cylindrical suction nozzle is extended to the suction port of the casing shell, and the tip of the suction nozzle is extended into the mouth of the impeller. Features a sheet metal whirlpool pump. 2. The sheet metal centrifugal pump according to claim 1, wherein a liner ring is attached to the tip of the suction nozzle extending into the mouth of the impeller. 3. The sheet metal centrifugal pump according to claim 1, wherein a protrusion extending in the circumferential direction is provided on the outer periphery of the suction nozzle.