JPH0151679B2 - - 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. Further, in this case, a configuration has been adopted in which rotating parts such as bearings of the motor rotating 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, a simple structure such as a direct coupling coupling that also serves as the flywheel, as mentioned above, is a solution. I had no means. 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 the exposed flywheel becomes a resistor, and depending on the environment around the suction port, various problems such as long foreign objects becoming entangled may occur. 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.

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, has a simple structure, and can prevent water hammer.

[Means for solving problems]

The submersible pump according to the present invention includes: a motor part, a shaft seal part including a mechanical seal,
The pump parts are successively arranged on the same rotating shaft in order, an air chamber is formed in the motor part, and a first pump part is arranged in the air chamber in order from the shaft seal part side.
A bearing, a flywheel, a rotor, and a second bearing are arranged, an appropriate number of vanes are formed on the side surface of the flywheel on the rotor side so as to generate a circulation flow for cooling the motor, and the rotating shaft and It is characterized in that the flywheel is integrally fixed.

[Effect]

When the motor section starts, water is sucked and discharged at the pump section.

The first bearing, the flywheel, the rotor, and the second bearing 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 located within 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 water hammer prevention effect due to the slow deceleration rotation when the pump is stopped is high. 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.

Further, the blade portion of the flywheel generates a circulating flow within the air chamber by rotation of the flywheel. This circulating flow forcibly cools the rotor and stator of the motor, thereby preventing burnout due to heat generation.

Example A first example showing an example 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 a wire outlet, 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 consists 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. Lid fitting 5 and shaft sealing part 2
The inside of the inner cylinder 6 forms an air chamber 20 between the two. 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. The flywheel 11 arranged between the first bearing 21a and the rotor 9 is
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 and the like arranged on the side. Air chamber 20 of oil casing 12
A leakage reservoir 12a is formed on the outer surface. 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 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 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 easily and inexpensively prevented with a simple configuration in which only 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, 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. Furthermore, the inside of the motor section is forcibly cooled by the blades formed on the flywheel, and burnout of the motor due to heat generation is prevented, making it possible to obtain a highly reliable underwater motor. Furthermore, since the rotating parts such as bearings are placed in the air chamber, it is not necessary to fill and supply oil to the rotating parts such as bearings, so a high-performance submersible pump can be obtained with a simple configuration.

In this way, the submersible pump of the present invention has the inertial effect of the flywheel placed in the air chamber,
By interacting with the forced cooling effect using the flywheel blades, it reduces the number of pump stoppages due to failure, and also slows down the change in rotational speed when stopped, reducing the effects of water hammer. A submersible pump with excellent water hammer prevention effect 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,
9 is a rotor, 10 is a rotating shaft, 11 is a flywheel, 13 is a mechanical seal, 20 is an air chamber, 2
1a and 21b are bearings.

Claims (1)

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