JPS588295A - double suction centrifugal pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a double suction centrifugal pump.

Conventional Jinotane pumps have bearing cases attached to both outsides of the pump casing, and oil-lubricated bearings. In addition, a seal part is provided at the shaft penetration part to prevent water leakage and air intrusion.
This requires a space between the pump and the rounded bearing to facilitate maintenance, which increases the overall length of the pump in the axial direction, complicates the structure, and increases cost. Furthermore, since the bearing span becomes long, the shaft deflection becomes large, and the sliding part between the impeller and the fixed side of the casing is worn out, resulting in a large drop in efficiency.

In the present invention, an underwater bearing is provided in the shaft penetrating part of the casing, and by supplying its own discharge water and returning it to the suction part, water lubrication is performed, and the "thrust force" in the left and right directions that occurs due to hydraulic imbalance is also eliminated. This design provides a double-suction centrifugal pump that can be miniaturized, improved in reliability, and manufactured at low cost by adopting a structure that supports the pump. ´ The double-suction type impeller is symmetrical and naturally handles unbalanced forces in the axial direction. Although the shape is such that it does not occur, unevenness of the suction flow,
If there are differences in shape due to manufacturing errors, etc., an axial thrust force will actually be generated. A thrust bearing is required to receive this, but in order to make the bearing smaller, a circumferential pocket is provided on a part of the thrust bearing surface to supply high-pressure water. Generates a force in the opposite direction to the unbalanced thrust force, thereby alleviating the thrust force acting on the bearing surface. Furthermore, the rotor is hydraulically stabilized and has the effect of returning to the nine position.

An embodiment of the present invention will be described below (see FIGS. 1 and 2). An impeller 2 is attached to the pump shaft 1 and is supported by bearings 4.5 on both sides of the casing 3. A shaft coupling 13 is attached to one end of the pump shaft 1 to be connected to a prime mover (not shown). In the shaft penetration part on the shaft coupling 13 side, there is a bearing 4 which receives a radial load.High pressure water from the discharge part 6 is introduced into the outer periphery of the bearing 4 through the conduit 7, and is connected to the shaft sleeve 15 through the through hole 14. It enters the gap, provides lubrication and cooling, and returns to the low pressure part 9 on the suction side.

A seal 16 is attached to the atmosphere side to prevent water from coming out to the outside, and a combination seal is provided to prevent atmospheric air from being sucked in when the suction side is under negative pressure.

On the opposite side of the shaft joint 13, there is a bearing 5 that receives a radial load and a thrust bearing 11 that receives a thrust load on its end face. .

The thrust collar 17 fixed to the shaft 1 also has two holes and provides the necessary axial clearance for the shaft sleeve 18. High-pressure water from the discharge part 6 is passed through a conduit 7 to the outer periphery of the bearing 5, passes through a through hole in the center, passes through a gap with the shaft sleeve 18, and passes through the thrust bearing surface 19 to provide lubrication and cooling. Return to the low pressure section 9 on the suction side. (The bearing 5 can be divided into two parts in the center.) Since the shaft end side chamber 8 is provided with a conduit 10 that connects to the low pressure part 9 on the suction side, the same pressure as the suction part is maintained, so the high pressure water described above is the same. Then, it passes through the shaft end side chamber 8 and returns to the low pressure part 9 on the suction side.

Since the thrust bearing surface 19 is provided with a circumferential pocket 12, the thrust load F acts from right to left in the direction of the arrow, and when running, the thrust bearing 11 on the right side comes into close contact with the thrust collar 17, and the thrust bearing 11 on the left side comes into close contact with the thrust collar 17. Since there is a slight gap between the bearing surfaces 19 and 19, a reaction force At due to high pressure water is generated on the right thrust bearing surface.

The load on F-A is alleviated.

Depending on the pressure water and the size of the pocket, it is easily possible to press DA and F into contact with each other, and the thrust load acting on the bearing surface can be greatly reduced, making it possible to downsize the bearing. .

According to the present invention, a bearing that receives radial load and thrust load is provided in the shaft penetration part of the casing, and the self-discharged water is guided as lubricating water (or high-pressure water can be supplied from another source) and returned to the suction chamber. You can get the following effects. .

(1) The entire pump is small and has a simple structure, so it can be manufactured at low cost. Also, the installation area can be reduced.

(2) The bearing span is approximately 60% compared to the conventional structure, reducing shaft deflection and reducing wear on sliding parts.
Increased rigidity reduces vibration by half, improving reliability.

(3) Maintenance is easy because there is no oil-lubricated bearing.

(4) There is only one shaft seal, reducing water leakage to the outside by half.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a detailed view of the bearing portion on the side opposite to the shaft joint in FIG. l... Pump shaft, 2... Impeller, 3... Casing, 4°5... Bearing, (radial bearing), 6... Discharge part, 7... Conduit, 8... Shaft end side chamber, 9... Low pressure part on the suction side, 1o... Conduit, 11... Thrust bearing, 12... Pocket, 13... Shaft coupling, 14...
Through hole, 15...Shaft sleeve 116...Seal, 1
7...Thrust collar, 18...Shaft sleeve, 19
...Thrust bearing surface.

Claims (1)

[Claims] An impeller 2 is provided at the center of the pump shaft 1, and bearings 4 and 5 are provided on both sides of the casing 3 to support the shaft. It has a conduit 7 that leads from the discharge part 6 to the bearing 4.5, and a conduit 10 that connects the shaft end side chamber 8 and the low pressure part 9 on the impeller suction side, so that the thrust bearing 11 receives forces in both left and right directions. A double suction centrifugal pump characterized in that it has a circumferential pocket 12 in a part of its thrust receiving surface.