JPS63295891A - Screw centrifugal pump - Google Patents

Abstract

PURPOSE:To enable a corrosive fluid to be forcibly delivered by forcibly feeding fluid by means of an impeller, on the nearly cylindrical inner surface of whose ceramic body a tapered female-screw-shaped screw centrifugal vane is formed, and a conical fixed body. CONSTITUTION:An impeller 1 is made up of a ceramic body on the inner surface of which a tapered female-screw-shaped screw centrifugal vane 1a is formed. A conical fixed body 2 is so arranged that its outer surface nearly conforms to the tapered shape of the inner surface of the impeller 1. A turning force is given to the impeller 1 by means of a driven magnet 15 and a driving magnet 16, and the liquid contacting parts are made of ceramics. Thus, even a corrosive fluid can be forcibly delivered, and abrasion also can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a screw centrifugal pump for pumping fluids such as sewage, mud, and chemical solutions, and particularly to a leak-free screw centrifugal pump.

[Conventional technology]

Screw centrifugal pumps are less prone to clogging even when pumping liquids containing solids, have higher suction capacity than general centrifugal pumps, and have limit-load shaft power characteristics that eliminate the risk of over horsepower. Because of these characteristics, it is used for pumping liquids containing solids and slurry materials.

As shown in Fig. 4, the structure of this screw centrifugal pump is such that an impeller I fixed to a rotating shaft K is disposed inside a casing C, and is equipped with a suction port A and a discharge port B communicating with the casing C. there were.

The impeller I is formed with blades H having a tapered male thread shape, and when the rotating shaft K is rotated by a drive device (not shown), the screw centrifugal action accompanying the rotation of the blades H causes fluid to be sucked in and absorbed. It was designed to be able to be fed under pressure to the discharge port B.

Furthermore, when pumping highly corrosive or toxic liquids, leak-free pumps are used that do not have any shaft seals and do not leak any of the liquid being handled. As shown in Fig. 5, the structure of this leak-free pump is such that a rotating body R is connected to the rear of an impeller l by a shaft, and the rotating body R is sealed with a partition tank S.
The rotating body R is equipped with a driven magnet H8, and by rotating a driving magnet M2 provided on the outside across the partition tank S, the rotating body R generates rotational motion, and the rotation is transmitted to the impeller I. It was like that.

[Problems with conventional technology]

However, in the screw centrifugal pump shown in Fig. 4, the impeller I, casing C, etc. are made of gray cast iron or high chromium cast iron, which not only makes it impossible to pump highly corrosive fluids (also, it cannot be used for long periods of time due to high wear). There was a problem that it was not possible to use .

In order to solve the above problems, a screw centrifugal pump in which the impeller I, casing C, etc. are made of ceramic has also been developed, but the impeller I has a complicated blade H, and the blade H is machined by cutting. It was very time-consuming and costly. Furthermore, it has been difficult to firmly fix the impeller l made of ceramic to the rotating shaft K made of metal.

In addition, the leak-free pump shown in Fig. 5 has a rotating body R at the rear of the impeller I, so the structure is complicated and it is difficult to make it compact. The structure for circulating the fluid was complicated.* [Means for solving the problem] In view of the above, the present invention provides an impeller in which a tapered female thread-shaped screw centrifugal blade is formed on the inner surface of a substantially cylindrical ceramic body; A screw centrifugal pump is constructed of a conical fixed body arranged to match the inner surface of the impeller, and the impeller is rotated to pump liquid.

〔Example〕

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

FIG. 1 shows a cross section of a screw centrifugal pump according to an embodiment of the present invention, in which the impeller is made of a ceramic body with a tapered female screw-shaped screw centrifugal vane 1a formed on its inner surface. A conical fixed body 2 is arranged so as to substantially match the tapered inner surface of the impeller 1, and a pump internal space is formed by combining a casing 4 to which the fixed body 2 is fixed and a front cover 3. The impeller 1 is rotatably supported by a bearing 8.11 in the internal space of the pump, and the part of the impeller 1 in contact with the bearing 8 is provided with a sleeve 9 and a thrust washer 10, and the part in contact with the bearing 11 is provided with a sleeve 12 and a thrust washer 10. Washers 13 are respectively provided, and when the impeller 1 rotates, fluid can be pumped from the suction port 5 to the discharge port 6.

Further, the size of the gap between the boss 2 and the centrifugal screw blade 111a can be adjusted using the clearance adjustment screw 7.

Furthermore, the impeller 1 is equipped with a driven magnet 15 covered with a sleeve 1b, and a pulley 14 equipped with a drive magnet 16 is rotatably arranged on the outside across the casing 4. By rotating the pulley 14, rotational force can be generated in the impeller 1.

In addition, a groove is formed in the bearing 8.11, and high-pressure liquid from the high-pressure discharge port 6 side passes through the groove in the bearing 11, passes through the outer circumference 1q of the impeller l, and passes through the groove in the bearing 8. The liquid then flows back to the suction port 5, and has a sparse structure so that the reflux liquid lubricates and cools the bearing.

Note that not only the impeller 1 (but also the fixed body 2, which is a wetted part)
, front cover 3, casing 4, bearing 8.11. It is more effective if the sleeve 9.12 and the thrust washer 10.13 are all made of ceramic.

In the screw centrifugal pump according to the embodiment of the present invention, the liquid-contact parts are made of ceramic, so that corrosive fluid can be pumped under pressure, and there is little wear.

In addition, by rotating the impeller l having screw centrifugal blades 1a formed on its inner surface by magnetic force from the outside, and by forming the discharge port 6 horizontally, it is possible to obtain a small leak-free pump with a very compact structure. Furthermore, the area of the root portion of the centrifugal screw blade 1a is thicker than that of the conventional screw centrifugal blade 1a, so the strength of the centrifugal screw blade 1a is large.

Next, another embodiment of the present invention will be described.

The screw centrifugal pump shown in FIG. 2 has almost the same structure as the one shown in FIG. 1 is rotated.

Next, a method for manufacturing the impeller 1 will be explained. The impeller 1 is a substantially cylindrical body made of ceramic, and has a tapered internally threaded centrifugal screw blade 1a formed on its inner surface, but such a shape can be formed by a rubber press method, a casting method, etc. .

For example, when using the rubber press method, as shown in Figure 3, a middle mold 2 with a tapered male thread shape and a smooth surface is
0 is prepared, a ceramic raw material powder 22 is put between the inner mold 20 and the rubber mold 21, and the space is sealed.Then, the ceramic raw material powder 22 is placed between the inner mold 20 and the rubber mold 21, and the mixture is sealed. 1
00100O/cm2). After molding,
Since the ceramic expands when the pressure is reduced and a minute gap is created between the ceramic and the middle mold 20, and the middle mold 20 has a tapered male thread shape, the middle mold 20 can be removed while being twisted.

In this way, the impeller 1 is homogeneous, the particles are well packed, and the deformation and shrinkage due to sintering are small and uniform, so the impeller 1 with excellent precision can be easily obtained without grinding the inner surface.

In addition, alumina, zirconia, silicon carbide, silicon nitride, nylon, etc. are used as the ceramic for forming the impeller 1 and other liquid-contact parts, but from the viewpoint of wear resistance and corrosion resistance, silicon carbide, silicon nitride was the best.

As an example of the present invention, the screw centrifugal pump shown in Fig. 1 was prototyped with all wetted parts made of alumina, and was used for pumping slurry together with the conventional screw centrifugal pump made of high chromium cast iron shown in Fig. 4. We compared the lifespan and performance using In the conventional type, the impeller etc. were severely worn after six months to one year and the performance deteriorated so much that it could not be continued to be used, whereas the type according to the present invention has a lifespan of about 2 to 3 times longer. It was also excellent in terms of performance.

〔Effect of the invention〕

According to the present invention, there is no leakage from the impeller made of a ceramic body with a tapered female thread-shaped screw centrifugal vane formed on the inner surface and the conical fixed body arranged to match the inner surface of the impeller. By configuring the screw centrifugal pump, it is possible to pump even corrosive fluids, and it can be used for a long period of time due to less wear. It also has a very simple structure and can be made into a small pump. Furthermore, the impeller can be formed easily and at low cost by a rubber press method or the like, and the screw centrifugal pump has many features such as increased strength of the screw centrifugal vanes.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a screw centrifugal pump according to an embodiment of the invention, and FIG. 2 is a sectional view showing another embodiment of the invention. FIG. 3 is a sectional view showing a method of forming an impeller constituting the screw centrifugal pump of the present invention. FIG. 4 is a sectional view showing a conventional screw centrifugal pump, and FIG. 5 is a sectional view showing a conventional leak-free pump. 1: Impeller 2: Fixed body 3: Front cover 4: Casing 5: Suction port
6: Discharge port 8.11: Bearing

Claims (2)

[Claims] (1) An impeller consisting of a tapered internally threaded screw centrifugal blade formed on the inner surface of a substantially cylindrical ceramic body, and a conical fixed body arranged to match the inner surface of the impeller, which rotates the impeller. A screw centrifugal pump characterized in that it pumps fluid under pressure. (2) The screw centrifugal pump according to claim 1, wherein a magnetic material is disposed in the impeller, and the impeller is rotated by an external driving magnet.