JPS63302189A - Eccentric screw pump - Google Patents

Abstract

PURPOSE:To provide a non-leak pump which is simple in structure and decreased in size, by a method wherein a rotor is followingly rotated through rotation of a stator. CONSTITUTION:A stator 1 is formed in an oblong in cross section, and is pro vided with a female screwlike inner surface. A rotor 2 is formed in the shape of a female screw formed in a circle in cross section being eccentric to a rotary shaft, and is mounted to the inner surface of the stator 1 so that the axes thereof are positioned eccentrically to each other by a distance (e). In which case, when a pulley 17 is rotated with the aid of a motor, as a result of a drive magnet 18 and a driven magnet 19 being attracted to each other, a rota tion force is transmitted to the stator 1. With the stator 1 rotated, the rotor 2, mounted such that it is positioned eccentrically to the axis of the stator 1 by the distance (e), performs planetary movement for rotation, and as a result, a pump action is produced to feed fluid with a pressure from a suction port 5 to a delivery port 6. This constitution enables an eccentric screw pump to be prevented from leak through simple structure, and facilitates maintenance since there is entirely no joint part, and permits the use of the pump for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an eccentric screw pump suitable for transporting highly viscous fluids.

[Conventional technology]

Eccentric screw pumps have the advantage of being able to pump even highly viscous fluids and have quantitative properties, so they were used to pump highly viscous fluids such as oil, paint, and pulp liquids, as well as chemical solutions and foods.

As shown in Fig. 3, the structure of this eccentric screw pump consists of a male screw-shaped rotor R having a circular cross section that is eccentric with respect to the rotation axis, and a male screw rotor R having an oval cross section and a pitch twice that of the rotor R. The stator S has a female threaded inner surface, and the rotor R has two universal screws J, J.
, a shaft F was connected via a connecting rod C and sealed with a shaft seal H. When the rotor R is rotated by the shaft F, the rotor R rotates around the rotation axis and moves eccentrically with respect to the axis of the fixed stator S, thereby moving the fluid from the suction port A to the discharge port. It was now possible to send it under pressure to B.

Further, the stator S was made of metal, and the rotor-shaped connecting rod c1 shaft F, etc. were all made of metal.

[Problems with conventional technology]

However, the conventional eccentric screw pump has a structure in which torque is transmitted to the rotor R by the shaft F, and requires a shaft seal H, which causes the handled liquid to leak, resulting in highly corrosive liquid, high vapor pressure, and explosion and ignition. This method has the disadvantage that it is not suitable for handling dangerous liquids, toxic liquids, expensive liquids, liquids that deteriorate when exposed to outside air, etc.

Further, the shaft F and the rotor R are connected by two universal joints J, J so that the rotor R can perform eccentric movement around the axis of the stator S, and the universal joint J is in the pumped fluid. Therefore, fluid easily seeped into the universal joint J and caused a malfunction.

For example, in an eccentric screw pump used for pumping pulp, the universal joint J tends to become difficult to rotate after about three months of use, and the universal joint J must be disassembled and maintained each time, or the universal joint J must be replaced with a new one. However, it was extremely time-consuming.

Further, the conventional eccentric screw pump requires many parts such as two universal joints J, a connecting rod C, and a shaft F, and has a complicated structure, making it difficult to downsize.

In addition, since the rotor R rotates while being in strong pressure contact with the inner surface of the stator S, the stator S made of metal or rubber is prone to wear, and wear debris gets mixed into the pumped fluid, which is especially important when pumping food. This had become a problem.

[Means for solving problems]

In view of the above, the present invention provides an eccentric screw pump in which a rotor and a stator are rotatably supported, and when the stator is rotated, the rotor is rotated dependently, and fluid is pumped. It is composed of

〔Example〕

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

In FIG. 1, l represents a stator, which has an oval cross section and an internally threaded inner surface. 2 is a rotor;
The rotor 2 has a male screw shape with a circular cross section eccentric to the rotating shaft, and the rotor 2 is mounted on the inner surface of the stator 1 so that their axes are offset by a distance e. These stator 1 and rotor 2 are completely sealed by a suction casing 3 with a suction port 5 and a delivery casing 4 with a discharge port 6, forming a leak-free pump. The stator 1 is rotatably supported by a bearing 7.8, and the part of the stator 1 in contact with the bearing 7 is provided with a sleeve 9 and a thrust washer 10, and the part in contact with the bearing 8 is provided with a sleeve 11 and a thrust washer 12. The rotor 2 also has a thrust bearing 13.1.
5. It is rotatably supported by radial bearings 14 and 16.

Furthermore, a pulley 17 is rotatably provided outside the suction casing 3, and the pulley 17 is provided with a drive magnet 18, and the stator 1 is provided with a driven magnet 19, respectively.

The operation of the leak-free eccentric screw pump configured as in the above embodiment is as follows: First, when the boolean IJ 17 is rotated by a motor (not shown), the driving magnet 18 and the driven magnet 19 attract each other, thereby transmitting rotational force to the stator 1. be done. Stator 1
When the rotor 2 rotates, the rotor 2, which is mounted eccentrically by a distance e from the axis of the stator 1, performs planetary motion and rotates, and as a result, a pumping action is generated and fluid can be pumped from the suction port 5 to the discharge port 6. It looks like this.

Additionally, a groove is formed in the bearing 7.8, and the high pressure liquid on the discharge port 6 side passes through the groove in the bearing 7 by utilizing the pressure difference from the high pressure discharge port 6 side to the suction port 5 side. Then, the liquid passes through the outer circumference of the stator l, passes through the groove of the bearing 8, and flows back toward the suction port 5, and this circulating liquid performs a lubricating and cooling action.

Note that in the above embodiment, the stator 1, which is a wetted part,
, rotor 2, suction casing 3, delivery casing 4, bearing 7.8, sleeve 9° 11, thrust washers 10, 12, thrust bearing 13.15, radial bearing 14.16, etc. are all made of ceramic.
more effective.

The eccentric screw pump according to the embodiment of the present invention has a simple structure and can be leak-free, and since there are no joints, maintenance is easy and it can be used for a long period of time. Furthermore, if the wetted parts are made of ceramic,
Even corrosive fluids can be pumped with less wear.

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

The eccentric screw pump shown in FIG. 2 has almost the same structure as the one shown in FIG.
0 is arranged to form a canned motor, and the stator 1 is rotated.

In addition, in these eccentric screw pumps, the rotor 2
The stator 1 rotates in strong pressure contact with the inner surface of the stator 1, but if the stator 1 is made of ceramic as described above, there will be less wear and there is less risk of mixing abrasion particles into the pumped fluid.

The stator 1 has an oval cross section and an internally threaded inner surface so as to rotate the oval. In order to form the stator 1 from ceramic, it is necessary to Using a male-threaded medium mold with a smooth outer surface, it is molded using a rubber press method or casting method.
After molding, the inner mold may be removed while being twisted. After the stator 1 formed in this manner is fired, the inner surface is polished to give a smooth surface for use.

The ceramics forming the stator l and other liquid-contact parts include alumina, zirconia, silicon carbide, silicon nitride,
Sialon and the like are used, but silicon carbide and silicon nitride are the most superior in terms of wear resistance and corrosion resistance.

〔Effect of the invention〕

According to the present invention, in an eccentric screw pump, the rotor and the stator are each rotatably supported, and the stator is rotated to cause the rotor to rotate dependently, thereby pumping the fluid easily. The compact structure makes it possible to create a small leak-free pump, and since there is no joint part, it is possible to maintain excellent performance over a long period of time without causing failure. Furthermore, if the wetted parts are made of ceramic, it is possible to provide an eccentric screw pump that has many features such as being able to pump even corrosive fluids and having increased wear resistance.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an eccentric screw pump according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing another embodiment of the invention. FIG. 3 is a longitudinal sectional view showing a conventional eccentric screw pump. 1: Stator 2: Rotor 3: Suction casing 4: Delivery casing 5: Suction port 6: Discharge port

Claims (1)

[Claims] It consists of a male-threaded rotor whose circular cross-section center is eccentric with respect to the rotation axis, and a stator which has an oval cross-section and a female-threaded inner surface, and the axis of the stator and the rotation axis of the rotor are eccentric. In an eccentric screw pump in which a rotor is housed in a stator, the rotor and the stator are each rotatably supported, and by rotating the stator, the rotor is rotated dependently, and fluid is pumped. Features: Eccentric screw pump.