JPS6111496A - Underwater dredger pump - Google Patents

Abstract

PURPOSE:To simplify construction, shorte piping, and reduce resistance loss by driving a main centrifugal pump and a subcentrifugal pump for jet water by a coaxial motor in common and allowing the suction port of the subcentrifugal pump to communicate to a nozzle close to a drug mouth. CONSTITUTION:A subcentrifugal pump 10 for jet water is coaxially connected to a main centrifugal pump 10, and driven by a common motor 14, and the discharge port of a pump 40 is connected to a nozzle close to a drug mouth 30 through a conduit 50. With such constitution, construction is simplified markedly, and piping is shortened, and resistance loss can be reduced, and operation performance can be improved. Further, fixed vanes 47a radially extending towards a back liner 47 are formed so that the pressure in the gap 55 between the side plate of the vane wheel 44 of the pump 40 and the back liner 24 is maintained higher than the pressure in the gap 58 between the side plate of the vane wheel 18 of the pump 40 and the back liner 24. Therefore, pure pressurized water circulates from the gap 55 into the gap 58 through a gland passage 56, and each service life of the vane wheel 18, back vane wheel 28, and the liner 24 can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a main centrifugal pump for collecting bottom aggregate;
A drag mouth pipe connected to the suction port of the main centrifugal pump, a sub centrifugal pump for jet water for agitating and suspending bottom aggregate, and a drag mouth pipe connected to the discharge port of the sub centrifugal pump by a conduit. and a nozzle that opens near the opening of the submersible dredge pump.

Generally, this type of submersible dredge pump is used for seabed aggregate,
It is used to collect land aggregates, riverbed aggregates, etc., and is generated by applying jet water from a jet water centrifugal pump to the aggregates deposited on the water bottom to disturb and suspend the aggregates. Collect the aggregate mixture by suctioning it through the opening of the drag mouth tube of the main centrifugal pump. However, in conventional submersible dredge pumps, the main centrifugal pump for collecting aggregate is operated at the bottom of the water, while the jet water pump is located in a facility above the water surface. Since the jet water pump is installed separately and independently in this way, the space for the facilities above the water surface becomes smaller, and the distance from the facilities above the water surface to the drag mouth pipe of the main centrifugal pump on the bottom is <1
The comparatively long piping in the pipes increases costs, causes high pipe resistance, has poor operability, and requires troublesome maintenance and inspection.

SUMMARY OF THE INVENTION An object of the present invention is to provide a submersible dredger pump which eliminates the above-mentioned drawbacks, has a simple structure, can be manufactured at low cost, has low power loss, and has good operability.

To achieve the above object, the present invention provides a main centrifugal pump and a sub-centrifugal pump that are coaxially connected and driven by a common motor, and the discharge ports of the sub-centrifugal pump are connected to the nozzles by a conduit. A ground passage is provided that communicates the gap between the back blade of the impeller side plate of the centrifugal pump and the back liner with the gap between the impeller side plate of the auxiliary centrifugal pump and the back liner. Means may be provided to maintain the pressure in the gap between the liners higher than the pressure in the gap between the impeller side plate of the main centrifugal pump and the backliner.

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

FIG. 1 shows a longitudinal sectional view of an underwater dredger bomb according to the present invention.

This submersible dredger pump has a main centrifugal pump 1o for extracting bottom aggregate, the main centrifugal pump having a casing 12 and an impeller 18 fixed to a shaft 16 projecting from a motor 14. A front cover 20 connected to the suction port side of the casing, and an impeller 18 inside this front cover.
and an annular back liner 24 mounted at an opening in the casing 12 opposite the suction port of the main centrifugal pump 10. The side plates on both sides of the impeller 180 are usually provided with front and rear blades l2 in order to reduce the axial thrust and to prevent foreign matter from entering the gap between the side plates of the impeller and the casing.
6.2g is provided.

Furthermore, a drag mouth tube 30 is attached to the end of the intermediate bracket 20. The inlet opening of this drag mouth tube 30 is located approximately horizontally near the bottom of the water.

According to the present invention, the main centrifugal pump 10 is provided with a jet water sub-centrifugal pump 40 coaxially adjacent to the main centrifugal pump 10 for agitating and suspending the bottom aggregate. The jet water sub-centrifugal pump 40 includes a casing 42, an impeller 44 fixed to the motor shaft 16 with a cap nut 43,
It consists of an intermediate bracket 46 fixed to the casing 42 and a back liner 47 fixed to the casing 42. From the intermediate bracket 46, the suction port 4 of the impeller 44 is connected.
A clear water suction pipe 48 communicating with 5 protrudes upward.

The outlet 49 of the casing 42 is guided by a conduit 50 close to the opening of the drag mouth tube, where it opens with a nozzle 52 .

Furthermore, according to the invention, a gap 58 between the back vane 28 of the impeller side plate of the main centrifugal pump 10 and the back liner 24 and a gap 58 between the impeller side plate and the other bank liner 47 of the auxiliary centrifugal pump 40 are provided.
A ground passage 56 is provided to communicate the gap 55 between the auxiliary centrifugal pump 40 and the back liner 47.
A means for making the pressure higher than the pressure in the gap 58 between the zero impeller side plate and the back liner 240, that is, in this embodiment, a fixed blade 47a extending radially is formed on the back liner 47. FIG. 2 shows a plan view of the back liner 47 on which the fixed blades 47a are formed. In this embodiment, when the motor 14 is operated, pressure water is generated between the rotating impeller side plate of the auxiliary centrifugal pump 40 and the fixed blade 47a, while the back blade of the rotating impeller plate of the main centrifugal pump 10 Since the pressure decreases between 28 and the back liner 24, a pressure difference is created between the gaps 58 and 55, and clean pressure water flows from the gap 55 on the sub-centrifugal pump side to the gland passage 56 as shown by the arrow.
It circulates through the gap 58 on the main centrifugal pump side. As a result, the back blade 28 and the annular back liner 24 made of aggregate are formed.
In addition, the life of the impeller 18 and the back liner 24 can be extended. In this embodiment, the fixed vane 47a is provided as a means for making the pressure in the gap 55 on the side of the auxiliary centrifugal pump 40 higher than the pressure in the gap 58 on the side of the main centrifugal pump 10. A pressure difference can also be created by designing the car to have a larger diameter. However, if this is done, the power consumption of the auxiliary centrifugal pump 40 increases, so the power used by the main centrifugal pump 10 decreases accordingly.

The circulation flow rate of the clear water circulation passage formed by the trench, the gap 55, the ground passage 56, and the gap 58 can be adjusted using an orifice plate.

In the present invention, a jet water auxiliary centrifugal pump is coaxially connected to the main centrifugal pump of a basin for collecting bottom aggregate, these pumps are driven by a common motor, and the discharge port of the auxiliary centrifugal pump is connected near the drag mouth. Since the pump is connected to the nozzle by a conduit, the structure is extremely simple and can be manufactured at low cost compared to the conventional configuration of two separate pumps, and the piping is extremely short, resulting in low resistance loss. ,1
- Operability has also improved.

Furthermore, in the present invention, a ground passage is provided that communicates the gap between the back blade of the impeller side plate of the main centrifugal pump and the back liner, and the gap between the impeller side plate of the auxiliary centrifugal pump and the back liner, and the auxiliary centrifugal pump A means is provided to maintain the pressure in the gap between the impeller side plate and the back liner of the main centrifugal pump to be higher than the pressure in the gap between the impeller side plate and the back liner of the main centrifugal pump. This allows the mixture to constantly flow through the gland passage into the gap between the impeller back blade of the main centrifugal pump and the backliner, thereby preventing the deposit mixture of the main centrifugal pump from entering the gland, Therefore, wear of the annular backliner of the impeller back blade of the main centrifugal pump can be prevented and the life of the impeller and annular backliner can be extended. Also, since the mixed liquid flows directly into the gland between the motor shaft and the casing, there is the advantage that sealing is easier.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of a submersible dredge pump according to the present invention, and Fig. 2 shows a fixing device provided as a means for increasing the gland pressure between the jet water sub-centrifugal pump and the main centrifugal pump on the sub-centrifugal pump side. FIG. 2 is a view of the blade taken along the line ■-■ in FIG. 1; 10・e・Main centrifugal pump 14−・Motor 18・
...Main centrifugal pump impeller 24...Back liner 2
8...Back blade 30...Drag mouth tube 40...Sub-centrifugal pump 44@-Regular centrifugal pump impeller 52...Nozzle 47...Back liner 47a...Higher the gland pressure on the sub-centrifugal pump side Means 56...Grand passage

Claims (1)

[Claims] (1) A main centrifugal pump for collecting bottom aggregate, a drag mouth pipe connected to the suction port of the main centrifugal pump, a sub-centrifugal pump for jet water to disturb and suspend the bottom aggregate, and a sub-centrifugal pump for jet water to agitate and suspend the bottom aggregate. In a submersible dredge pump having a nozzle connected by a conduit to the discharge port of the centrifugal pump and opening near the opening of the drag mouth tube, a sub-centrifugal pump is coaxially connected to the main centrifugal pump to provide a common pump. Driven by a motor, the discharge port of the auxiliary centrifugal pump is connected to the nozzle by a conduit, and the gap between the back blade of the impeller side plate of the main centrifugal pump and the back liner and the gap between the impeller side plate of the auxiliary centrifugal pump and the back liner are connected. Means for maintaining the pressure in the gap between the impeller side plate of the auxiliary centrifugal pump and the backliner higher than the pressure in the gap between the impeller side plate of the main centrifugal pump and the backliner, while providing a ground passage that communicates the gap between them. A submersible dredge pump characterized by being provided with.