JPS58202395A - Mixed-flow submergible pump - Google Patents

Abstract

PURPOSE:To reduce the undesirable influence of closing of a flow passage by a cable groove, by setting a cable groove for power source so as to bite into a flow passage on the concaved surface outer wall side of a vane at the max. diameter part of a guide vane and forming said guide vane type flow passage to be flattened in the direction of the three-dimensional curve. CONSTITUTION:On the outer wall 11a of a guide vane 6, a groove 9 for motor power cable 10 is formed in the direction of pump axis on the part corresponding to the outer wall part B of a vane concaved surface at the max. diameter part 12 of the flow passage of the guide vane 6. Therefore, the section of the flow passage is formed flattened in the direction of the three-dimensional curve, as shown in the figure, at the inlet part of the guide vane 6 where the three- dimensional curve is sharp, and thus the secondary stream is suppressed, and the stream on the inner wall A side of a vane convex wall which tends to be exfoliated from the meridian surface flow passage is restrained towards inner- wall side, and generation of exfoliation is delayed. Therefore, the undesirable influence of closing the flow passage 6 of the guide vane 6 due to the cable groove 9 can be utilized for the control of the guide vane 6 inside flow inversely.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the flow path between the guide vanes of a mixed flow submersible pump for a well.

In submersible well pumps, the electric motor for driving the pump is usually installed below the pump in order to obtain as much water as possible in as small a space as possible.

That is, in FIG. 1, l is a pump driving electric motor,
The motor shaft 3 and the pump shaft 4 are coupled by the coupling ZK, while the motor power cable 10F'i is routed from the ground into the well 17 along the discharge pipe 7, and in the pump part, the outer wall of the guide vane 6 Fixed. Due to the required discharge pressure, a plurality of impellers 5 are fixed to the pump shaft 4 and rotated by an electric motor 1. As the impeller 5 rotates, water is drawn in from a suction strainer 8 provided between the electric motor 1 and the pump, and is energized by the impeller 5. Furthermore, while this water passes through the guide vanes 6 distributed behind the impeller 5, it recovers the dynamic pressure component in the energy given by the impeller 5 to static pressure, and from then on, the energy is given by the impeller 5. The discharge pressure is increased while the static pressure is repeatedly recovered by the guide vanes 6, and the discharge pressure flows out into the discharge pipe 7.

Standards have been established for submersible pumps for wells (J
iS, B8324-1977, Submersible Motor Pump for Deep Wells), in addition to the standard well diameter, the maximum pump diameter including cables etc. is specified for each well diameter.

Therefore, conventionally, the maximum diameter of the guide vane flow path and, in turn, the outer diameter of the impeller were determined from the cable dimensions and the guide vane wall thickness.

On the other hand, the amount of water pumped from a well depends on the amount of groundwater springing up, and even if the well diameter and depth are the same, the amount of water that can be pumped differs depending on the land. For this reason, there is a demand to prepare pumps with different water pumping amounts, that is, specific speeds, for each well diameter, and to select the pump that operates most efficiently depending on the spring water amount. In this case, in a high specific speed pump, it is necessary to form a guide vane flow path wide even if the impeller diameter is the same. Therefore, in small-diameter wells where the cable dimension or guide vane wall thickness is relatively large with respect to the well diameter, the high specific speed pump
As shown in the figure, a part of the outer wall of one guide vane 6 has a groove shape 9, and the guide vane has a shape in which a power cable 10 is passed through the groove 9. However, in the guide vane 6 shown in Fig. 2, the guide vane flow path is locally blocked in the circumferential direction at the cable groove 9, and the flow from the impeller 5 collides and suddenly contracts at this part. This resulted in rapid expansion and reduced efficiency.

On the other hand, in order to avoid the influence of the cable #19 on the flow path shape of the guide vane 6, it is also possible to make the inner wall 11b of the guide vane 11 wider inward and reduce the outer diameter of the impeller 5 to obtain the same specifications. It is possible. However, when the impeller is made smaller with the same specifications, the degree of reaction of the impeller decreases, and the slope of the head curve decreases as shown in FIG. Therefore, if the pipe resistance changes due to changes in well water level due to fluctuations in spring water, the operating point of the pump will change significantly, which will not only be disadvantageous in terms of efficiency and suction performance, but also cause excessive flow. This is especially preferable for submersible pumps, since the shaft power becomes significantly excessive when operating on the side, and there is a risk of burning out the motor.

Direction, D, tl pump specification point, RfIII'i piping resistance curved piping resistance real case, fLtzFi is the case of large spring water flow. The case of P, Fi low recoil pump 7, Phd high recoil pump is shown. M (represents the motor capacity.

F is the operating range of the low recoil pump, and Fbd is the operating range of the high recoil pump.

An object of the present invention is to form the guide vane flow path so as to be flat in the direction of three-dimensional bending by selecting the circumferential position of the power cable groove for the electric motor, thereby improving the secondary flow and the meridional flow. The objective is to suppress the separation of surface flow and alleviate the adverse effects of channel blockage by cable grooves.

FIG. 4 shows the outer wall side 11a of the guide vane 11 shown in FIG.
FIG. 4A is a developed view of the inner wall side 11b, and FIG. 4A corresponds to the outer wall side, and FIG. 4B corresponds to the inner wall side. The guide vane 6 is shown in Fig. 2 and Fig. 4.
As shown in the figure, a three-dimensional airflow user forms a curved flow path in each of the meridional flow path and the inter-blade flow path, and recovers the dynamic pressure of the flow from the impeller 5 to static pressure. becomes.

Therefore, in the cross section of the guide vane flow path, as shown in Fig. 5, a secondary flow 0 occurs from the convex inner wall side A of the vane corresponding to the inside of the three-dimensional curve toward the concave outer wall *BK, and the curvature of the three-dimensional curve On the inner wall side A of the blade convex surface where the flow is the steepest, the flow becomes easier to separate.

To suppress this secondary flow C, Japanese Patent Publication No. 49-13524 proposed an improvement in which the blade shape was formed as shown by the broken line in Figure 5, and the guide vane flow path was flattened in the direction of three-dimensional bending. It is publicly known. In the present invention, the position of the motor power cable groove, which blocks the guide vane flow path and adversely affects the flow, is provided in the concave outer wall of the guide vane.
It is characterized by producing the same effect as No. 524.

Embodiments of the present invention will be described below with reference to FIGS. 6 to 8. 6 is a longitudinal cross-sectional view of the guide vane 6, and FIG. 7 is a view taken along the line AA' in FIG. 116. Guide blade 60 blade outer wall 11a
In the guide vane 6, a groove 9t for the motor power cable 10 is provided in a portion corresponding to the root gH of the concave outer wall of the guide vane 6 in a portion corresponding to the root gH of the concave outer wall of the guide vane 6 in the direction of the pump axis. Therefore, Figure 8a~
As shown in Fig. 8b, in the flow path up to the maximum diameter portion 12 of the guide vane, the cable groove 9 bites into the flow path BK on the outer wall side of the concave surface of the blade, which is the outside of the three-dimensional curved flow path, and the flow path after the maximum diameter 12. In the channel, it interferes with the guide vane flow path so as to bite into the outer wall on the convex side of the vane.

Since the guide vane according to the present invention has the above-mentioned configuration, the flow path is tightly forged, and therefore the guide vane 6 is likely to cause secondary flow.
In the 0-input section, the cross-sectional shape of the flow path is flat in the three-dimensional direction, and the linear flow is suppressed by the same effect as in Japanese Patent Publication No. 13524 of 1972.

On the other hand, in the flow path downstream of the guide vane maximum diameter section 12, the cable groove position moves to the outer wall side of the convex surface of the vane, so that the expansion of the meridional flow path is somewhat alleviated among the rapid expansion of the three-dimensional curved flow path on the convex surface of the vane. As a result, the flow D from the convex inner wall portion A of the blade is suppressed.

Note that on the outer wall side B of the concave blade surface downstream of the large diameter portion 12 of the blade, the interference of the cable groove 9 is eliminated, so the flow path rapidly expands in the meridian direction, but this portion is the outflow direction of the main flow of the impeller 51J. , and because the main flow tends to flow along the channel wall due to the centrifugal force of the three-dimensional bend, negative effects from sudden expansion are unlikely to occur.

As explained above, the present invention is characterized in that the cable groove for the submersible pump motor power supply is configured so that the maximum diameter part of the guide vane bites into the channel on the concave outer wall side of the vane. In this section, the cross-sectional shape of the flow channel becomes flat in the three-dimensional direction, suppressing secondary flow and restraining the flow on the inner wall side of the convex blade surface, where the flow tends to separate from the meridian flow channel, toward the inner wall side. By delaying the occurrence of separation and by utilizing the adverse effects of the guide vane flow path blockage by the cable groove to control the internal flow of the guide vane, a highly efficient guide vane can be obtained.

[Brief explanation of the drawing]

@ Figures 1 and 2 are diagrams explaining a conventional submersible mixed flow pump. Figure 1 is a vertical cross-sectional view of the entire pump, Figure 2 is a vertical cross-sectional view of the guide vane, and Figure 3 shows the operation of the pump. The characteristic diagrams to be explained, FIGS. 4 and 5, are diagrams explaining the flow in the guide vane flow path.
Fig. 4 is a developed view of the blade, Fig. 5 is a sectional view of the flow path, Figs. A-A' arrow view in Fig. 6,
FIG. 8 is a sectional view of each flow path in the flow direction. l...Electric motor, 5... Impeller, 6... Guide vane,
9... Cable groove, 10... Power cable, 11.
...Guide vane blade, A... Convex inner wall of the impeller, B... Concave outer wall of the impeller, C... Secondary flow nXD... Foil) Flow. E 1st eye 3rd block'z4 concave

Claims (1)

[Claims] In a mixed flow guide vane in which power is distributed to a pump driving electric motor toward the pump F side, and a groove for the motor power cable is provided on the outer wall of the flow path, the cable groove is installed near the root of the concave outer wall of the guide vane at the maximum diameter part of the guide vane. A diagonal flow submersible pump characterized by being formed to pass through.