JPH0115716B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a pump having a pump casing and an impeller rotatably provided within the pump casing and having a single spiral blade formed on a conical hub. The present invention relates to a pump useful for transporting a fluid containing a gas therein.

This type of pump is particularly used for transporting sludge, gas-containing oil, etc., and as shown in Figure 7, a truncated conical casing part 2 surrounding a spiral vane communicates with a discharge port. In the pump casing, there is provided an impeller in which a single blade 7 is spirally wound around a conical hub 8 extending in the axial direction. While the impeller is rotating, inside the truncated cone-shaped casing part 2, the blades function similar to a positive displacement pump, and since there is only one blade, a gentle flow occurs, and the centrifugal force causes a gentle flow of air or gas. Separation is difficult to occur, and even liquids containing some air can be transported without reducing the transporting force much, but in the swirl chamber casing part 3,
When the liquid is discharged by centrifugal force, air stagnation occurs as described below, reducing the pumping action. (General centrifugal pumps have a large number of blades, so most of the air is discharged as fine bubbles.) In other words, since the blade meridian cross section at the blade outlet is a mixed-flow type impeller, it is not parallel to the rotational axis as shown in the figure, but is tilted, and the pressure in the maximum diameter part A is large and the minimum diameter part B pressure is small. For this reason, a circulating flow as shown by the arrow in FIG.
happens inside. At this time, the air or gas becomes relatively fine bubbles in the large diameter portion of the impeller and is guided to the pump outlet and discharged, but some of the air or gas is carried by the circulating flow shown in Figure 7 and During this time, the air is constantly centrifuged and the pressure in part B is low, so the air expands and collects in part B as a large mass of air or gas, which flows to the pump outlet. It is not guided and stays in part B. As this develops, the impeller passage becomes narrowed by the trapped air or gas, reducing pumping performance. As this tendency increases, stagnant air or gas eventually reaches the pump inlet, making pumping impossible. The above mechanism was actually observed using a transparent acrylic casing.

SUMMARY OF THE INVENTION The object of the present invention is to provide a single-blade impeller pump that eliminates the above-mentioned drawbacks and improves the efficiency of transporting gas-containing liquids.

The above object is achieved according to the invention by providing a plurality of stirring blades on the outer periphery of the conical hub of the impeller.

According to this configuration of the present invention, when the liquid containing air is discharged by the centrifugal force in the volute chamber casing part, the large air bubbles that collect near the B part (FIG. 7) of the impeller are stirred by the stirring blade. The air is made into fine bubbles and discharged along with the above-mentioned circulating flow, and the rotation of the stirring blade increases the pressure in the low-pressure part of the small blade diameter so that the air does not expand, thereby doubling the action of making the bubbles fine and discharging them. Therefore, the pump flow rate is significantly increased compared to conventional single-blade impeller pumps. A pump having an impeller with stirring blades according to the invention is particularly effective in the case of highly viscous liquids that are difficult to escape from, such as sludge, gas-laden oil, etc.

Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, the pump casing for a single-blade impeller pump consists of a frusto-conical casing part 2 with an inlet 1 and a volute casing part 3. FIG. Prime mover (not shown)
The shaft end 4a of the rotating shaft 4 is supported by a bearing on the side.
, an impeller flange 5 is fixed by a nut 6, and a conical hub 8 having a single spiral blade 7 is attached to the impeller flange 5 by a bolt 9 screwed into the center of the rotating shaft end 4a. Fixed.

A large number of stirring blades 10 are provided on the outer periphery of the impeller flange 5, which exceeds the outer diameter of the base of the conical hub 8, according to the present invention. The stirring blades 10 can be arranged in a radial manner as shown in FIG. 4, or at an angle as shown in FIG. Moreover, as shown in FIG. 6, it is of course possible to arrange the blades in a curved line.

FIG. 3 shows another embodiment of the invention. Components similar to those in FIG. 2 are numbered similarly.
The difference between this embodiment and the embodiment shown in FIG. 2 is that the impeller flange 10 fixed to the rotating shaft end 104a
5 has a small outer diameter, and a large number of stirring blades 110 are provided directly on the outer periphery of the conical hub 108 of the impeller that extends beyond the outer diameter.

In operation, during the rotation of the single-bladed impeller 5, the vane section within the frusto-conical casing section 2 acts similar to a positive displacement pump, transporting the aerated liquid, and also transporting the aerated liquid into the volute chamber casing section 3. In this method, a liquid containing air is discharged by centrifugal force, but at this time, the large air bubbles that tend to collect near part B of the impeller (Fig. 7) are turned into fine air bubbles that are stirred by the stirring blade 10, and the agitator 10 is used to create fine air bubbles. The air is discharged along with the circulating flow inside the casing (Figure 7), and the rotation of the stirring blade increases the pressure in the low-pressure part of the small blade diameter, preventing air expansion and doubling the action of atomizing and discharging air bubbles. .

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of only the casing of a single-blade impeller pump equipped with stirring blades according to the present invention;
FIG. 2 is a vertical cross-sectional view of the pump shown in FIG. 1, with the impeller attachment part also taken in section, FIG. 3 is a vertical cross-sectional view similar to FIG. 2 of another embodiment of the present invention, and FIGS. 4 to 6 7 is a front view showing various ways of arranging the stirring blades of the present invention, and FIG. 7 is a longitudinal sectional view of a conventional single-blade impeller pump. 2, 3... Pump casing, 7... Single blade, 8... Conical hub, 10, 110... Stirring blade.

Claims (1)

[Claims] 1. In a pump having a pump casing and an impeller rotatably provided within the pump casing and having a single spiral blade formed on a conical hub, a plurality of impellers are provided on the outer periphery of the conical hub of the impeller. A single-blade impeller pump characterized by being equipped with a stirring blade.