JPH0151680B2 - - Google Patents

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-based pumps have included the use of surge tanks or air tanks, and the addition of a flywheel to the pump motor or direct coupling. In the latter case, the motor part, shaft seal part,
A pump is already known in which the pump parts are connected in sequence on the same rotating shaft (US Pat. No. 3,215,083).

However, in this configuration, the flywheel, which rotates at high speed and has a large mass, is fitted onto the outer circumferential side of a cylindrical shaft that does not rotate, and is fixed to the rotating shaft via the rotor and the support member. Therefore, in this configuration, it is difficult to employ a flywheel having a sufficiently large mass due to strength problems. Also, that configuration requires additional bearings to prevent the flywheel from cantilevering.

On the other hand, most submersible pumps have a structure in which the shaft of the submersible motor also serves as the pump shaft, so a solution with a simple structure, such as a direct coupling coupling that also serves as the flywheel, as in the above-mentioned land pump, is available. I was bored. 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 various other inconveniences occur, such as the exposed flywheel becoming a resistor or, depending on the environment around the suction port, long foreign objects becoming entangled. Further, in order to maintain a configuration in which rotating parts such as a bearing of a motor rotating shaft are filled with oil, it is difficult to adopt a configuration in which oil can be supplied to a submersible pump. Therefore, a surge tank or an air tank has generally been used as a solution for submersible pumps.

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

In view of the above-mentioned current situation, it is an object of the present invention to provide an inexpensive submersible pump that is free from water resistance during operation, has a simple structure, and can sufficiently prevent water hammer.

[Means for solving problems]

The submersible pump according to the present invention is a submersible pump in which a motor part, a shaft seal part, and a pump part are connected in this order around the same rotating shaft. The submersible pump according to the present invention includes an air chamber formed within the motor section, and a flywheel disposed in the air chamber near the boundary with the shaft seal section. The flywheel is integrally supported with its center part fitted and fixed to the rotating shaft. Further, a curved recess is formed on the side surface of the flywheel on the shaft sealing side, for scattering water leakage that enters the air chamber from the shaft sealing side toward the shaft sealing side.

[Effect]

When the motor section starts, water is sucked and discharged at the pump section. At this time, the flywheel also rotates together. Since the flywheel is integrally supported by fitting and fixing the center portion to the rotating shaft, strength can be ensured even if the flywheel has a sufficiently large mass.

When the pump is stopped, the inertia of the flywheel, which has a sufficiently large mass, does not cause the pump to suddenly stop, and the speed of the discharge flow is gradually reduced due to the slow deceleration rotation. Therefore, even if the discharge piping is long, water hammer can be prevented from occurring. Furthermore, since the flywheel is located within the air chamber, the rotation of the flywheel is not hindered by oil or water. Therefore, the effect of preventing water hammer due to the slow deceleration rotation when the pump is stopped is high.

In addition, since the flywheel is fitted and fixed to the rotating shaft and is integrally supported, there is no looseness between the flywheel and the rotating shaft, and there is no problem with strength. Demonstrate longevity.

Furthermore, a curved recess is formed on the shaft seal side of the flywheel, so if water leaks from the shaft seal side, this leakage water will be scattered to the surrounding wall or the shaft seal side, and the motor will be This prevents insulation failure due to water leakage in rotors, stators, etc.

〔Example〕

A first embodiment showing an embodiment of the submersible pump according to the present invention.
As is clear from the figure, the motor part 1, the shaft seal part 2, and the pump part 3 are sequentially connected from above to form a vertical submersible pump having a watertight structure. Although not shown, there is provided a connection means that can be automatically connected to the discharge pipe fixed to the bottom of the tank in advance, using, for example, known hanging means and elevating guide means.

The motor part 1 mainly includes an upper lid 4 having an electric wire outlet part, a lid fitting 5 having a wiring board, an inner cylinder 6 and an outer cylinder 7 arranged concentrically with each other, and is attached to the inner peripheral surface of the inner cylinder 6. It is composed of a stator 8, a rotor 9 disposed on the inner peripheral side of the stator 8, and 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. In the air chamber 20, a first bearing 21a, a flywheel 11, a rotor 9, and a second bearing 21b are arranged in order from the shaft seal portion 2 side. The rotating shaft 10 is rotatably supported by a pair of bearings 21a and 21b. Flywheel 11 arranged between first bearing 21a and rotor 9
The center portion thereof is fitted and fixed to the rotating shaft 10 and is integrally supported.

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 functions as a fan. An appropriate number of through holes 9a formed in the rotor 9 are suction passages, and an appropriate number of cavities 6a formed penetratingly between the inner cylinder 6 and the outer periphery of the stator 8 are discharge passages (second (see figure), rotation of the flywheel 11 causes 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 part 2 mainly includes an oil casing 1 equipped with a first bearing 21a on the flywheel 11 side.
2. Pump part 3 inside oil casing 12
It is composed of a mechanical seal 13 placed on the side. Air chamber 2 of oil casing 12
A water leakage reservoir 12a is formed on the outer surface relative to 0. A water leakage detector 14 is disposed within the water leakage reservoir 12a, and is configured to emit a signal as appropriate.

The pump section 3 mainly includes a pump casing 15 integrally formed with a discharge port, and a pump casing 1.
5, an impeller 16 rotatably disposed within the pump casing 5, a suction side lid fitting 17 attached to the lower end of the pump casing 15, and the like. A back space 18 of the impeller 16 that communicates with the discharge side communicates with a cavity 19 formed between the inner and outer cylinders 6 and 7 through passages formed in each of the casings 12 and 15.

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 to cool the inside of the motor section 1.
On the other hand, the rotation of the flywheel 11 generates a circulating air flow passing through the through hole 9a and the hollow part 6a, and the air that is cooled when passing through the hollow part 6a generates heat in the rotor 9 when passing through the through hole 9a. absorb.

In the unlikely event that water leaks through the rotating shaft 10 and attempts to rise 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. The water then travels 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 stop abruptly due to the inertia of the flywheel 11 having a sufficiently large mass, 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.

On the other hand, since the flywheel 11 is fitted and fixed to the rotating shaft 10 and is integrally supported, play may occur between the flywheel 11 and the rotating shaft 10, and strength problems may occur. It has a long life without any problems.

Although the above description relates to a vertical structure, substantially the same configuration can be easily implemented in a horizontal structure.

〔Effect of the invention〕

According to the submersible pump according to the present invention, the occurrence of water hammer can be sufficiently prevented easily and inexpensively by a simple configuration in which a flywheel is provided in the air chamber within the motor portion near the shaft seal portion. Furthermore, since the flywheel is placed within the air chamber, problems such as resistance loss due to water or oil and entanglement of foreign objects do not occur. Therefore, a higher water hammer prevention effect can be expected. Furthermore, because the flywheel is integrally supported by fitting and fixing its center to the rotating shaft, there is a risk of looseness or strength problems between the flywheel and the rotating shaft. You can get a long-life submersible pump without having to worry about it. Furthermore, the curved recess formed in the flywheel prevents poor insulation of the motor section due to water leakage from the shaft seal, and prevents the pump from stopping due to motor failure.

Further, due to the above-described interaction of the flywheel, there is no abnormal stoppage due to motor failure, etc., and by performing a slow stopping motion, a submersible pump that is excellent in preventing water hammer can be obtained.

[Brief explanation of drawings]

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 the motor part, 2 is the shaft seal part, 3 is the pump part,
10 is a rotating shaft, 11 is a flywheel, and 20 is an air chamber.

Claims (1)

[Scope of Claims] 1. A submersible pump in which a motor part surrounded by a motor casing, a shaft seal part, and a pump part are connected in this order around the same rotating shaft, comprising: an air chamber formed in the motor part; a flywheel disposed indoors near a boundary with the shaft seal, the flywheel having a central portion integrally supported by the rotating shaft; and a flywheel on the shaft seal side of the flywheel; A submersible pump characterized in that a curved recess is formed on a side surface for scattering water leakage that enters the air chamber from the shaft sealing portion side toward the shaft sealing portion side.