JPH0134317B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a self-priming centrifugal pump having a steam/water separation chamber.

Conventional structure and its problems In general, a self-priming centrifugal pump consists of a pump case 1, a casing 2, and a casing cover 3, as shown in Figs. 1 to 3, and is directly connected to the prime mover inside the pump case 1. A gasket 5 is interposed between the casing 2 and the casing cover 3 to form a volute chamber 6 and a return water passage 7 together with the casing 2 and a part of the casing cover 3. More volute room 6
A circulation hole 8 is provided that extends to. In the figure, 9 is a steam/water separation chamber, 10 is a suction port, and 11 is a discharge port.

In the above configuration, when the inside of the pump case 1 is filled with water by priming and the impeller 4 rotates, the pump performs a self-priming action. At this time, volute chamber 6
The steam-water mixture discharged from the volute chamber 6 is separated into steam and water in the steam-water separation chamber 9, and the return water passes through the return water passage 7 in the flow direction of the arrow 12 and is then passed through the reflux hole 8 provided on the front side of the impeller of the volute chamber 6. It is returned to the volute room 6.

Problems to be Solved by the Invention However, if the air-water separation chamber 9 is made smaller, the return water containing many bubbles will return to the volute chamber 6 through the above-mentioned path without sufficient air-water separation, reducing the self-priming efficiency. I will let you do it. On the other hand, if the steam/water separation chamber 9 is made larger, the overall shape of the device becomes larger.
Furthermore, a problem arises in which the pumping efficiency decreases after self-priming is completed.

Means for Solving the Problem In order to solve this problem, the present invention provides a return water passage having a shape in which the return water from the steam/water separation chamber provided in the upper part of the volute chamber is lowered and then raised. It consists of a return hole near the end of the return water passage and a rectifying wall that blocks the upper flow of return water near the lowest point of the return water passage.

Effect With this configuration, the return water containing air bubbles that has not been separated in the air-water separation chamber is collected at the top of the flow at the lowest point when passing through the return water passage. The passage of air bubbles is blocked and the amount returned to the volute chamber is reduced.

DESCRIPTION OF EMBODIMENTS FIG. 4 shows a return water passage section of a self-priming centrifugal pump according to an embodiment of the present invention, which is characterized by a rectifying wall hanging down from the upper wall 13 of a part of the return water passage 7. 14. Note that the other configurations are the same as those shown in FIGS. 1 to 3 above.

According to this configuration, the upper wall 1 of a part of the return water passage 7
By the rectifying wall 14 provided so as to hang down from 3,
The flow of air bubbles is blocked, and the return water from which air bubbles have been removed can be guided to the circulation hole 8 through the lower part of the rectifying wall 14. In other words, the larger the bubbles that adversely affect the self-priming action, the greater the buoyancy and the more likely they are to be blocked by the rectifying wall 14 because they move along the upper wall of the return waterway 7. Furthermore, when air bubbles that have been stopped by the rectifying wall 14 accumulate, their buoyancy increases, they go against the flow of the returning water, and are discharged from the discharge port in the direction of the arrow 15, which does not impede the self-priming action in any way. be. In addition, when the pumping operation returns to normal,
The rectifying wall 14 serves as a resistance for the return water passage 7, which is advantageous even during normal water pumping operation that does not require return water.

Effects of the Invention As described above, according to the present invention, the rectifying wall hanging down from the upper wall of the return water passage prevents the self-priming efficiency from decreasing when the air-water separation chamber is downsized. This makes it possible to reduce the size of the steam/water separation chamber, and to avoid the drop in pumping efficiency that would otherwise occur due to the large size of the steam/water separation chamber, thereby providing a pump with high pumping efficiency.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional self-priming centrifugal pump.
Figure 2 is a cross-sectional view taken along line A-A in Figure 1, and Figure 3 is a cross-sectional view of Figure 1.
FIG. 4 is a cross-sectional view of a return water passage of a self-priming centrifugal pump according to an embodiment of the present invention. 1...Pump case, 2...Casing, 3...
...Casing cover, 4... Impeller, 6... Volute chamber, 7... Return water passage, 8... Circulation hole, 9
... Air-water separation room, 14 ... Rectification wall.

Claims (1)

[Scope of Claims] 1. A steam/water separation chamber provided in the upper part of the volute chamber, a return water passage having a shape in which the return water from the steam/water separation chamber is once lowered and then raised; A self-priming centrifugal pump comprising: a return hole provided near a terminal end; and a rectifying wall that blocks an upper flow of return water flowing near the lowest point of the return water passage.