JPH09303281A - Structure of double barrel multistage pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use internal water for a lubrication purpose for the elimination of an external bearing lubrication device and reduce cost by providing a bearing in a shaft seal chamber, regarding the double barrel multistage pump where a balance circuit is laid so as to balance shaft seal chambers at both ends of an outer easing with suction pressure, and water lubricated bearing is used as a bearing. SOLUTION: One end of a pump shaft 1 is held on a shaft seal chamber 23 formed on one end plate 22, via a bearing 5, while the other end of the pump shaft 1 is held on a shaft seal chambers 25 formed on another end plate 24, via bearings 6 and 7. Also, the internal pressure of both shaft seal chambers 23 and 25 is kept equal to the internal pressure Ps of a suction chamber 26, and the internal pressure of a pump inner chamber 12 is kept at a value Pc raised with impellers 2 and 3, thereby causing internal water to flow from the pump inner chamber 12 to the shaft seal chamber 25 via differential pressure Pb across both sides of a balance bush 4. The internal water after flowing to the shaft seal chamber 25 is made to flow to another shaft seal chamber 23 through a balance piping 28, and bearings 5 to 7 are lubricated with a water flow through the piping 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner casing defining a flow passage for an inner fluid, an outer casing for containing inner water filled in the outer side of the inner casing, and a suction pressure for a shaft sealing chamber at both ends of the outer casing. The present invention relates to an improvement in the structure of a double-barreled multi-stage pump that uses a water-lubricating bearing as a bearing and a balance circuit.

[0002]

2. Description of the Related Art In such a conventional double cylinder multistage pump (for example, two stages), as shown in FIG. 2, an impellers 2 and 3 of a pump shaft 1A are surrounded and a flow passage 11 for an internal fluid is defined therein. Inner casing 10 and an outer casing 20A for containing the internal water filled outside the inner casing 10
And the shaft sealing chambers 23A and 2A at both ends of the outer casing 20A.
A balance pipe 28A, which is a balance circuit for balancing 5A with the suction pressure of the suction chamber 26, is provided as described later. Both ends of the pump shaft 1A are supported by the outer casing 20A via radial bearings 5 and 6 and a pair of thrust bearings 7, respectively. In the figure, reference numeral 4 is a balance bush, and 12 is a pump inner chamber.

[0003]

As the bearings 5, 6 and 7 of the conventional pump of this type, as shown by chain lines a, b and c, bearings of the type for supplying lubricating water or lubricating oil from the outside are used. And required an external bearing lubrication system. Therefore, it is necessary to install and maintain the external bearing lubrication device.

The initial cost of the lubricating device occupies a considerable proportion compared with the pump main body, and there are many troubles caused by the lubricating device, and the maintenance cost is high at present.

The present invention has been made in view of these circumstances, and an object thereof is to provide a structure of a double barrel multistage pump which does not require an external bearing lubricating device.

[0006]

According to the present invention, an inner casing defining a flow passage for an internal fluid, an outer casing for containing internal water filled outside the inner casing, and shaft seals at both ends of the outer casing are provided. In a structure of a double-barrel multistage pump that includes a balance circuit for balancing the chamber to the suction pressure and uses a water-lubricating bearing for the bearing, the bearing is arranged in the shaft-sealing chamber.

Further, according to the present invention, a shaft sealing chamber is provided outside both bearings at the shaft end, and both shaft sealing chambers are connected by a balance circuit.

In the structure of the double barrel multistage pump configured as described above, the internal water flows from the pump inner chamber to the pump inner chamber side shaft sealing chamber due to the differential pressure, and the other shaft sealing chamber is passed through the balance circuit. Return to the suction chamber via. The bearings provided in the shaft-sealing chambers are lubricated by this balance return flow.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In addition, in FIG. 1, portions corresponding to those in FIG.

In FIG. 1, one end of the pump shaft 1 is supported via a bearing 5 in a shaft-sealing chamber 23 formed in one end plate 22 of a main body 21 of an outer casing, which is generally indicated at 20. . The other end of the pump shaft 1 is supported by a shaft sealing chamber 25 formed in the other end plate 24 via bearings 6, 7 and 5. The shaft sealing chamber 23 and the outer end of the shaft sealing chamber 25 are communicated with each other by a balance pipe 28 which is a balance circuit. It should be noted that reference numeral 2 in FIG.
7 is a discharge chamber.

Next, the operation will be described.

The shaft-sealing chamber 23 communicates with the suction chamber 26, and the shaft-sealing chamber 23 communicates with the other shaft-sealing chamber 25 via a balance pipe 28. Therefore, both shaft sealing chambers 23,
The pressure of 25 is equal to the pressure Ps of the suction chamber 26. On the other hand, the pump inner chamber 12 has a pressure Pc boosted by the impellers 2 and 3. Therefore, the differential pressure Pb on both sides of the balance bush 4 is Pb = Pc-Ps, and the differential pressure Pb causes the internal water to pass through the gap between the balance bush 4 and the end plate 24 from the pump inner chamber 12 to the shaft sealing chamber. Flows to 25. The internal water flowing out to the shaft sealing chamber 25 flows into the shaft sealing chamber 23 through the balance pipe 28 and returns to the suction chamber 26. This balance return flow passes through the intermediate bearings 6, 7 and 5 and acts as lubricating water.

[0013]

Since the present invention is constructed as described above, by utilizing internal water for lubrication, an external bearing lubrication device is not required, and as a result, cost reduction and maintenance cost reduction can be achieved. The effect can be obtained.

[Brief description of drawings]

FIG. 1 is a side sectional view showing one embodiment of the present invention.

FIG. 2 is a side sectional view showing an example of a conventional double barrel multistage pump.

[Explanation of Codes] Pb ... Differential pressure 1, 1A ... Pump shaft 2, 3 ... Impeller 4 ... Balance bush 5, 6 ... Radial bearing 7 ... Thrust bearing 10 ... -Inner casing 11 ... running water channel 12 ... Pump inner chamber 20, 20A ... Outer casing 21 ... Main body 22, 24 ... End plate 23, 23A ... Shaft sealing chamber 25, 25A. ..Shaft sealing chamber 26 ... Suction chamber 27 ... Discharge chamber 28, 28A ... Balance pipe

Claims (2)

[Claims] 1. An inner casing defining a flow passage for an internal fluid, an outer casing for containing internal water filled outside the inner casing, and a balance circuit for balancing a shaft sealing chamber at both ends of the outer casing to suction pressure. In the structure of the double barrel multi-stage pump equipped with a water lubrication bearing,
A structure of a double-barrel multistage pump, wherein the bearing is arranged in the shaft-sealing chamber. 2. The structure of the double barrel multistage pump according to claim 1, wherein a shaft sealing chamber is provided outside both bearings at the shaft end, and both shaft sealing chambers are communicated with each other by a balance circuit.