JPS63154898A - Submersible pump - Google Patents

Abstract

PURPOSE:To prevent water hammer, by arranging a first bearing, a flywheel, a rotor and a second bearing sequentially in an air chamber formed in a motor section and securing the flywheel to a rotary shaft. CONSTITUTION:Upon rotation of a rotor 9 at a motor section 1, an impeller 16 sucks/delivers water and a portion of delivered water enters through a back face space 18 into a cavity 19 so as to cool the interior of the motor section 1. Rotation of a flywheel 11 causes production of a circulation flow passing through a through-hole 9a and an air gap section 6a so as to cool the rotor 9. When shaft sealing 13 is incomplete, water leaks upward along a rotary shaft 10 to the stator 8 side then stored in a leak water sump 12a through water-cut function of the flywheel 11 and said condition is detected through a water leak detector 14. When the operation is stopped, the pump is not stopped abruptly because of the flywheel 11 and since the components are arranged in an air chamber 20, rotation of pump is decreased gradually thereby water hammer can be prevented effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a submersible pump whose main purpose is to prevent water hammer.

[Conventional technology and its problems] Conventionally, measures to prevent water hammer caused by long distance piping in land pumps include the use of a surge tank or air tank, and the addition of a flywheel to the pump motor or direct coupling. The method of doing so was adopted. Further, in this case, a configuration has been adopted in which rotating parts such as bearings of the motor rotation shaft are filled with oil (for example, US Pat. No. 3,215,083).

On the other hand, since the mainstream for submersible pumps is a structure in which the shaft of the submersible motor also serves as the pump shaft, it is possible to use a simple structure such as the direct coupling that also serves as the flywheel, as described above for land use. There was no way to make a monthly decision. If an attempt is made to extend the pump shaft passing through the impeller to the outside of the pump and provide a flywheel outside the pump, it will be extremely difficult to employ a bearing means for the pump shaft. Moreover, not only does the overall length of the pump become longer, but also various problems occur, such as an exposed flywheel or resistor, and depending on the environment around the suction port, long foreign objects may become entangled. In addition, it is difficult to adopt a configuration in which oil can be supplied to a submersible pump, even though a rotating part such as a bearing of a motor rotating shaft is filled with oil. Therefore, a surge tank or an air tank has generally been used as a solution for submersible pumps.

Unfortunately, all such tanks require a considerable height or volume, which not only poses various problems in terms of installation space, but also increases equipment costs.

SUMMARY OF THE INVENTION In view of the above-mentioned current situation, an object of the present invention is to provide an inexpensive submersible pump that does not generate resistance due to water during operation and can prevent water hammer with a simple structure.

[Means for solving problems] The submersible pump according to the present invention includes; Motor part, shaft seal part including mechanical seal.

The pump parts are connected in sequence on the same rotating shaft, an air chamber is formed in the motor part, and in the air chamber, in order from the shaft seal part side, a first bearing;
The present invention is characterized in that a flywheel, a rotor, and a second bearing are provided, and the rotating shaft and the flywheel are integrally fixed.

[Operation] When the motor starts, water is sucked into the pump.
It is discharged.

The first bearing, flywheel, rotor, and second support are arranged within the air chamber. That is, since the rotating parts such as bearings are not configured to be filled with oil, there is no need to form a special oil passage for oil supply.

When the operation is stopped, the inertia of the flywheel prevents the pump from stopping abruptly, and the speed of the discharge flow gradually decreases due to the slow deceleration of rotation. Therefore, even if the discharge piping is long, water hammer can be prevented from occurring. Furthermore, since the flywheel is placed inside the air chamber, the rotation of the flywheel is not hindered by oil or water.

Therefore, there is no flywheel resistance loss due to water or oil, and the slow deceleration rotation when the pump is stopped is highly effective in preventing water hammer. Furthermore, since the flywheel is integrally fixed to the rotating shaft, there is no play between the flywheel and the rotating shaft, resulting in a long life.

[Embodiment] As is clear from FIG. 1 showing an embodiment of the submersible pump according to the present invention, a motor part 1, a shaft seal part 2, and a pump part 3 are successively arranged from above, It consists of a vertical submersible pump with a watertight structure.

Although not shown in the drawings, there is provided a connection means that can be automatically connected to the discharge pipe fixed to the bottom of the tank in advance, for example, by known hanging means and lifting guide means.

The motor part 1 mainly includes an upper lid 4 having an electric wire take-out part, a lid fitting 5 having a temporary wire connection, an inner cylinder 6 and an outer cylinder 7 arranged concentrically with each other, and is attached to the inner circumferential surface of the inner cylinder 6. a stator 8, a rotor 9 disposed on the inner peripheral side of the stator 8,
It consists of a rotating shaft 10 that is integrally fixed to the rotor 9 and serves as both a pump shaft and a motor shaft. An air chamber 20 is formed inside the inner cylinder 6 between the lid fitting 5 and the shaft seal part 2. Inside the air chamber 20, in order from the shaft sealing part 2 side, a first bearing 21a1, a flywheel co 1, a rotor 9, and a second bearing 2 are installed.
1b is placed. The rotating wheel] 0 is rotatably supported by a pair of bearings 21a and 21b. The flywheel 11 disposed between the first bearing 21a and the rotor 9 is integrally supported with its center part fitted and fixed to the rotating shaft 10.

An appropriate number of blades 11a are formed on the flywheel 11 on the side facing the stator 8, so that the flywheel 11 also serves as a fan. An appropriate number of through holes 9a formed in the rotor 9 are suction passages, and an appropriate number of voids 6a formed penetratingly between the inner cylinder 6 and the outer periphery of the stator 8 are discharge passages (see Fig. 2). ), rotation of the flywheel 11 generates a circulating air flow for cooling within these passages as shown by the arrows. Further, a recess 11b having an appropriately curved surface is formed on the side surface of the flywheel 11 on the shaft sealing portion 2 side.

The shaft sealing section 2 mainly includes an oil casing 12 having a first bearing 21a on the flywheel 11 side, a mechanical seal 13 disposed inside the oil casing 12 on the pump section 3 side, and the like. A leakage reservoir 12a is formed on the outer surface of the oil casing 12 relative to the air chamber 20.

A water leak detector 14 is arranged in the water leak reservoir 12a,
Signals are emitted as appropriate.

The pump section 3 mainly includes a pump casing 15 having an integrally formed discharge port, an impeller 16 rotatably disposed within the pump casing 15, a suction side lid fitting 17 attached to the lower end of the pump casing 15, and the like. It is configured. The back space 18 of the impeller 16 communicating with the discharge side is
Via a passage formed in each casing 12.15, it communicates with a cavity 19 formed between the inner and outer cylinders 6,7.

Next, the operation will be explained.

When the rotor 9 of the motor section 1 rotates, the impeller 16 rotates to suck in and discharge water. Through this operation, a portion of the discharged water fills the cavity 19 from the impeller back cavity 18 and cools the inside of the motor section 1.

On the other hand, due to the rotation of the flywheel 11, a circulating air flow passing through the through hole 9a and the gap 6a is generated.
The air cooled when passing through the through hole 98 absorbs the heat generated by the rotor 9.

In the unlikely event that water leaks along the rotary shaft 10 and rises toward the stator 8 due to a malfunction of the mechanical seal 13, the water will be scattered onto the inner wall of the inner cylinder 6 by the draining action of the flywheel 11. Water flows along the inner wall and collects in the leakage reservoir 12a. Then, water leakage is detected by the water leakage detector 14 transmitting a signal. Thereby, the motor can be protected. Note that the curved recess 11b cut into the flywheel 11 further improves the draining performance.

When the pump is stopped, the pump does not suddenly stop due to the inertia of the flywheel 11, and the speed of the discharge flow gradually decreases due to the slow deceleration rotation. Therefore, even if the discharge piping is long, water hammer is prevented from occurring. At this time, since the flywheel 11 is disposed within the air chamber 20, there is no resistance loss due to water, oil, etc., so the rotation of the pump gradually decelerates, and the effect of preventing water hammer is high.

Although the above description relates to a vertical structure, substantially the same configuration can be applied to a container having a horizontal structure.

[Effects of the Invention] According to the submersible pump according to the present invention, the occurrence of water hammer can be easily and inexpensively prevented by a simple configuration in which a flywheel is provided in the air chamber in the motor portion near the shaft seal portion. Moreover, since the flywheel is placed within the air chamber, defects such as resistance loss due to water or oil or entanglement of foreign objects do not occur. Therefore, a higher water hammer prevention effect can be expected. Furthermore, since the rotating shaft and the flywheel are integrally fixed, the flywheel does not rattle, making it possible to obtain a long-life underwater motor. In addition, by placing rotating parts such as bearings inside the air chamber, there is no need to fill and supply oil to rotating parts such as bearings, making it possible to obtain a high-performance submersible pump with a simple configuration. .

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional view, and FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1. 1 is a motor part, 2 is a shaft seal part, 3 is a pump part, 9 is a rotor, 10 is a rotating shaft, 11 is a flywheel, 13 is a mechanical seal, 20 is an air chamber, and 21a, 21b are bearings. (Katana S26)

Claims (3)

[Claims] (1) A motor part, a shaft seal part including a mechanical seal, and a pump part are connected in this order on the same rotating shaft, an air chamber is formed in the motor part, and a motor part, a shaft seal part including a mechanical seal, and a pump part are arranged in series in this order, an air chamber is formed in the motor part, and a second 1 bearing and
A submersible pump, characterized in that a flywheel, a rotor, and a second bearing are arranged, and the rotating shaft and the flywheel are integrally fixed. (2) The motor part has a protruding passage consisting of a through-hole formed at an appropriate number of locations on the circumference between the stator and the motor casing, and the stator consists of an appropriate number of through holes provided in the axial direction. 2. The submersible pump according to claim 1, further comprising a suction passage and an appropriate number of vanes formed on the side surface of the flywheel on the stator side so as to generate a circulation flow for cooling the motor. (3) A recess having an appropriately curved surface is formed on the side surface of the flywheel on the side of the shaft seal, a water leakage reservoir is provided in the air chamber at a position closer to the shaft seal than the flywheel, and a water leakage reservoir is provided within the water leakage reservoir. 3. The submersible pump according to claim 1 or 2, wherein a leak detector is disposed at an appropriate position in the submersible pump.