JP2617883B2 - Submersible motor pump and cabtyre cable used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a submersible motor for treating sewage, muddy water, gray water, etc. in civil engineering work, wastewater treatment, sewage treatment equipment and general industrial equipment using a submersible motor pump. It relates to a sand pump.

[0002]

2. Description of the Related Art A submersible motor pump that is generally put into practical use is a shaft sealing device such as a mechanical seal or an oil seal around a shaft between a dry type submersible motor and a pump. Are arranged in two stages, upper and lower, and oil is sealed between the shaft sealing devices. The lower pump side shaft sealing device requires the use of high-grade material that can withstand muddy water. In the underwater motor sand pumps, there are some pumps in which the motor chamber is pressurized with pressurized air or pressurized with an external water level pressure, based on the same concept as various diving equipment. Has not been reached.

[0003]

The fact that water in the motor chamber can be easily prevented by increasing the internal pressure of the submersible motor has not yet been put to practical use. The pressure changes depending on the operating condition of the pump and the start or stop of the pump, and adjusting the pressure by reflecting the change in the pressure on the supplied pressurized air requires a very sophisticated adjustment mechanism.
If this pressure change is directly applied to the shaft sealing device, the muddy water easily penetrates into the sealing surface of the shaft sealing device due to the displacement deformation of the seal surface, and the shaft sealing device is quickly damaged. .

[0004] Also, a mechanical seal or an oil seal
It is difficult to maintain a completely leak-free state for a long period of time even with shaft sealing devices such as
The occurrence of dew condensation in the motor room due to repeated temperature rise and cooling at the time of stoppage due to the heat generated by the bearings and shaft seals is unavoidable, which lowers the insulation of the motor. Further, when the air tube for supplying the pressurized air is supplied separately from the cab tire cable, the connection portion or the middle thereof is easily damaged, and the handling becomes complicated. In order to solve the above-mentioned problems, the present invention has an object to provide a submersible motor pump whose handling and structure are simplified and which can easily maintain pressurization in a motor room. is there.

[0005]

The above object of the present invention can be achieved by a submersible motor pump having the following configuration. That is, an air tube for supplying pressurized air is included in a cab tire cable for power supply in the same manner as the conductive wire, and the air tube is provided.
Pressurized air is supplied via an injection check valve provided in the motor chamber, and the pressurized air is supplied from a discharge hole provided with a discharge check valve provided below the motor chamber to a position below the shaft sealing device. After the air chamber is filled, the air is discharged from the pump through a window provided on the outer periphery of the lower case. Water leaking from the gap between the rear shaft circumference of the pump impeller and the inner circumference of the rear cover or the water sucked in is also freely released outside the pump, and the pressure change of the pump section is directly applied to the shaft sealing section. To prevent a gradual change in pressure around the external water level.

[0006]

As shown in FIG. 6, the submersible motor pump according to the present invention supplies compressed air to the air tube 10 at the beginning of the cabtire cable 8 when the compressed air is supplied to the cabtire. After passing through the cable 8, the injection check valve 11 at the upper part of the motor chamber b is pushed open, and the motor chamber b and the connection chamber a are filled and pressurized. If condensation water due to cooling while the pump is stopped, or water droplets due to intrusion water from the joint, etc., accumulates at a lower level, the discharge holes 22 provided in the lower case 16 or the lower case 16 of the motor chamber b are discharged. The check valve 12 is pushed open, and is discharged together with the pressurized air into an air reservoir chamber c formed in the seal cover 17 below the shaft sealing device 15. An air layer is created below to prevent the shaft sealing device 15 from directly contacting muddy water.

The air that fills the air reservoir chamber c and leaks from below is released to the outside of the pump through the window d on the outer periphery of the lower case 16. Even if the impeller 18 of the pump section 23 is planned to be balanced with the internal pressure of the pump by the action of the back impeller, the operating state of the pump may be higher or lower than the external water level water pressure. For this reason, external water is sucked in from the inner peripheral gap between the boss portion of the impeller 18 and the back cover 20 when the inner peripheral portion of the back blade of the impeller 18 has a negative pressure, and the pump chamber e has a high pressure. Although the internal water leaks out, it is opened to the outside of the pump through the window d, and the change in pressure applied to the air reservoir chamber c and the shaft sealing device 15 can be made as gradual as the minimum change in water level outside the pump. The supply of pressurized air can be sealed most reliably if the pump is supplied irrespective of whether the pump is operating or stopped. Condensed water generated in the motor chamber b can be sequentially discharged, and the air in the air chamber c can be discharged. The pressure difference between the pressure and the motor chamber b can be set as required by the strength of the spring of the discharge check valve 12.

[0008] By supplying pressurized air from the cabtire cable in this way, the motor chamber pressure is adjusted according to the spring force of the injection check valve and the discharge check valve, and the cabtire cable is released.
Since the pressure in the underwater motor chamber is maintained lower than the pressure in the air tube in the cable and higher than the pressure in the air reservoir chamber, that is, the external water level pressure, the external water in the underwater motor chamber from the joints and shaft seals. In addition, the shaft sealing device is isolated by an air layer, and muddy water can be prevented from coming into direct contact. Also, if moisture contained in the pressurized air or water droplets generated for some reason during stoppage stays in the motor chamber, it is immediately discharged by the pressurized air from the lower discharge hole, and the motor is discharged. Contributes to preventing insulation deterioration of the rotor and preventing rusting of bearings. Even if the supply of pressurized air is stopped, the motor
The pressure inside the chamber is maintained at the internal pressure at the time of stoppage by the action of the injection check valve and the discharge check valve, and flooding is prevented. Even when the water level outside the pump rises and the water level pressure rises, the air in the air reservoir chamber is maintained in an air layer while being compressed, preventing muddy water from contacting and protecting the shaft sealing device.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A submersible pump according to the present invention will be described below in detail with reference to the drawings showing an embodiment thereof. As shown in FIGS. 1 to 3, the cabtire cable 8 includes an air tube 10 for air supply in addition to a normal conductive wire 9, and its starting end is connected to a switchboard A. With the above air
The starting end of the tube 10 is connected to a compressed air source B such as an air compressor. At the end of the cabtire cable 8, the lead port cover 6 on the upper part of the motor case 4 is penetrated in a watertight manner, and the upper connection chamber in the upper cover 5 of the motor chamber b. a, and connected to the stator 1 of the motor, the rotor 2 is excited and rotated, and the air tube 10 is shown in FIG.
Connected to the injection check valve 11 having a mechanism as shown in FIG.
It is opened in the chamber b.

Next, the drive shaft 3 of the motor is supported by a bearing 13 having an upper portion provided on a bearing ring 14 and a lower portion provided on a lower case 16, and is provided with a shaft sealing device 15 connected below the bearing 13. And droop down to the lower pump chamber e to drive and rotate the impeller 18. Below the seal cover 17 for accommodating the shaft sealing device 15, an air reservoir c is formed in a shape like a dish or a bowl facing down. Furthermore,
The bearing 13 of the lower case 16 below the turbine chamber b
The upper part of the outer periphery is opened at the lowest possible position of the motor chamber b, and the lower part is provided with a discharge hole 22 which penetrates through the seal cover 17 and reaches the air reservoir chamber c, as shown in FIG. The communication is made via a discharge check valve 12 having a simple mechanism.

Several windows d are provided on the outer periphery of the lower case 16 and are opened to the outside so that water leaking from the back of the impeller 18 can be used.
Alternatively, a configuration is adopted in which the inflow and outflow of the inhaled water are made free, and the air leaking from the air reservoir chamber c is released outside the pump. The pump unit 23 is constructed by arranging a suction cover 19 on the front surface of the impeller 18, a rear cover 20 on the rear surface and a casing 21 on the outer periphery, and a lower case 16 of the motor.
To join.

[0012]

As described above, according to the present invention, first, the pressurized air is supplied through the cabtire cable, thereby remarkably damaging the air supply tube and the connection port. Thus, it is possible to eliminate the trouble of separately handling the air supply tube. Also, in the underwater motor room, the insulation loss and rusting of bearings can be prevented by sequentially discharging the dew condensation water or the intruding water droplets and preventing the water from entering by the pressure difference.

[0013] In the shaft sealing device, the temperature rise and cooling of the motor chamber due to the operation of the pump, and the abrupt change in the impeller back pressure which occurs when the pump is started, during operation, and when stopped, is prevented. It is possible to maintain an ideal state in which the motor chamber pressure is almost constant and high. In addition, the material and structure can be reduced to a low level because they do not come into direct contact with muddy water. For the above effects, comprehensively, without changing the handling from the conventional pump except connecting the pressurized air source,
A submersible sand pump with significantly improved repair time can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of an underwater motor sand pump according to an embodiment of the present invention.

FIG. 2 is an explanatory sectional view of a cabtire cable of the present invention.

FIG. 3 is a conceptual explanatory view of a switchboard at the beginning of a cabtire-cable according to the present invention.

FIG. 4 is an enlarged sectional explanatory view of an inlet check valve of the present invention.

FIG. 5 is an enlarged sectional explanatory view of a discharge check valve of the present invention.

FIG. 6 is an explanatory view of the operation of the present invention.

[Explanation of symbols]

 b motor chamber c air trap chamber 8 cabtire cable 10 air tube 11 injection check valve 12 discharge check valve 15 shaft sealing device 18 impeller 22 discharge hole 23 pump part

Claims (2)

(57) [Claims] In a submersible motor pump having a dry type submersible motor at an upper part and a pump part at a lower part, pressurized air is injected through an injection check valve provided in a motor chamber. Then, the air pressurized in the motor chamber is released into the air chamber below the shaft sealing device provided in the lower part of the motor chamber.
A discharge hole provided with a discharge check valve is opened at the bottom of the motor chamber, and the discharged air is sucked or leaked from the excess air after filling the air reservoir and the clearance behind the pump impeller. A submersible pump characterized by a mechanism that allows water to be released outside the pump. 2. A hollow tube that can be used for air supply like a conductive wire is provided inside a conductive cabtire cable connected to the underwater motor pump. A cabtire cable used in a submersible motor pump.