JPH01208599A - Centrifugal pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a complete centrifugal pump with a casing ring.

(Prior Art) Conventional centrifugal pumps are as described in ``Japan Society of Mechanical Engineers Line 9 Iso Mechanical Engineering Section, Volume 9, Chapter 3, Pumps, Pages 9-42, Figure 113''. In other words, as shown in FIG.
The liquid sucked in from a is pressurized by the rotation of one impeller 3, and is discharged into a thin chamber 1b formed in the casing to become a high-pressure liquid and pumped. A portion passes through the gap C between the side plate 3a of the impeller and the casing ring 4 attached to the casing as a swirling flow J, and flows out into the suction flow 1% la. This leakage flow having a swirling component is directed toward the main flow M from the suction flow path 1a toward the impeller inlet.

Because the flow directions were not the same, when the two converged, the main flow was disturbed, causing a decrease in the suction performance and efficiency of the pump.

In addition, Japanese Patent Application Laid-Open No. 59-12899111 is cited as a related technology, which provides a guide vane just before the population of one vane to directly change the flow direction of the main flow toward the inlet (to create a swirling flow). , which improves efficiency, and the technical problem and solution are different from the present invention.

[Problem to be solved by the invention]

As mentioned above, in the prior art, a single flow leaking from the gap between the impeller side plate and the casing ring is opposed to the main flow from the suction flow path to the impeller inlet.

Since the flow directions are not the same, there is a problem in that the main flow is disturbed, thereby reducing the suction performance of the pump. In addition, since the leakage flow blocks the main flow along the inner surface of the side plate of the first impeller, the boundary layer along the side plate of the first impeller develops significantly, resulting in loss due to separation of the boundary layer and backflow. It was also the cause of the decline.

An object of the present invention is to reduce the phenomenon in which the main flow sucked into the impeller is disturbed or separated from the inner surface of the side plate due to the swirling flow leaking from the gap, and to obtain good suction performance and efficiency. be.

[Means to solve the problem]

The above purpose is to provide a plurality of plate-shaped ribs arranged circumferentially on the side surface of the casing ring facing the suction port end surface of the impeller side plate, and to adjust the angle of the ribs with respect to the radial direction from the suction flow path to the impeller inlet. This is achieved by approximately matching the turning angle of the flowing mainstream.

[Effect]

By adopting the above means, the swirling flow that has passed through the gap between the impeller side plate and the casing ring is guided by the ribs to change its swirling angle, and near the rib exit, it is sucked into the impeller inlet. The main flow flows out with almost the same turning angle as the main flow.

Therefore, the leakage flow smoothly merges with the main flow, and the turbulence of the main flow that conventionally occurs can be reduced. This makes it possible to improve pump suction performance.

In addition, since the leakage flow has almost the same speed and direction as the main flow, it is possible to reduce the phenomenon in which the main flow along the side plate inside the impeller is separated from the inner surface of the side plate due to the leakage flow, and the development of a boundary layer in this area can be reduced. It can be suppressed. Therefore, loss caused by separation of the boundary layer, etc. is reduced, and efficiency can be improved.

[Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 3. In FIG. 1, inside the casing 1.

An impeller 3 that is rotated and driven by the rotating shaft 2 is housed. A casing ring 4 is arranged so as to face the outer peripheral surface of the suction port of the side plate 3a of the impeller with a small gap C therebetween.
is fixed to the casing 1, and a plate-shaped rib 5 is provided on the side surface of the impeller side plate 3a of the casing ring that faces the suction port end surface. Note that the rib inner diameter φDa is made larger than the center diameter φDe of the impeller side plate 3a so as not to affect the mainstream flow. 2 and 3 show a cross section taken along the line AA in FIG. 1 in the direction of the arrow, and a plurality of ribs 5 on the side surface of the casing ring are arranged on the circumference. The angle 0 of the rib 5 with respect to the radial direction is set to approximately match the turning angle of the main flow M sucked into the impeller 3. Figure 2 shows the angle 0
In this example, the main flow in the suction flow path has no swirling component (Brillo-Chasion). Figure 3 shows an example in which the angle θ0 is set to the radial direction, This is a case in which the main flow M within has a swirling component.

In the centrifugal pump configured as described above, the rotating shaft 2
When the impeller 3 rotates, liquid is sucked into the impeller 38 from the suction channel of the casing 1. After being pressurized by the single impeller 3, the liquid is discharged into a swirl chamber formed within the casing, and pumped up as a high-pressure liquid. Since this is similar to the conventional pump shown in FIG. 4, the entire structure is omitted in FIG. A part of the high-pressure liquid in the swirl chamber passes through the gap C between the outer circumferential surface of the suction port of the side plate 3a of one impeller and the inner surface of the casing ring 4 facing it, as a swirling flow, and flows into the impeller. When it comes out from the side plate 3a, it collides with the side surface of the casing ring, changes the flow direction downward (in the axial direction), and leaks to the impeller suction port. At this time, the downward swirling flow collides with the plate-shaped rib 5 attached to the side surface of the casing ring, and not only velocity energy is consumed (speed decreases), but also due to the guidance of the rib,
The turning component is zero (Fig. 2) or the required turning angle is 0.
@ (Figure 3).

At the rib outlet, it flows out as a circumferential flow J' that is almost the same as the main flow M, and merges with the main flow M. Therefore, compared to the conventional case where the swirling flow leaking from the gap C merges with the main flow without matching the flow direction, the degree of disturbance of the main flow can be significantly reduced, as described in the [effect] section above. To,
Good suction performance and efficiency can be obtained.

〔Effect of the invention〕

According to the present invention, by controlling the leakage flow from the gap between the impeller side plate and the casing ring so that the flow direction matches the flow direction of the main flow, turbulence in the main flow after merging can be reduced. As a result, the flow sucked into one impeller can be made uniform,
This has the effect of obtaining good suction performance.

Furthermore, since the development of a boundary layer is suppressed at the junction of the leakage flow and the main flow, loss is reduced, pump efficiency is improved, and power costs can be reduced.

The present invention can be widely applied to centrifugal pumps having a casing ring since it is only necessary to slightly change the structure of the casing ring.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of the main part showing an embodiment of the present invention, FIG.
FIG. 3 is a sectional view taken along the line A-A in FIG. 1, showing two examples with different rib angles, and FIG. 4 is a longitudinal sectional view showing the overall structure of a centrifugal pump to which the present invention is applied. be. 1...Casing, 1a...Suction channel of the casing. 1b... Vortex chamber in the casing, 2... Rotating shaft,
3... Impeller, 3a... Side plate of impeller, 4... Casing ring, 5... Rib. 1 b.

Claims (1)

[Claims] 1. Opposed to the outer peripheral surface of the suction port of the side plate of the rotating impeller,
In a centrifugal pump having a casing ring attached to the casing through a minute gap, a plurality of plate-shaped ribs are arranged circumferentially on the side surface of the casing ring facing the suction port end surface of the side plate, and the A centrifugal pump characterized in that the angle of the rib with respect to the radial direction approximately matches the swirling angle of the main flow from the suction channel to the impeller inlet.