CN209925277U

CN209925277U - Axial force balancing device for auxiliary water supply steam driven pump

Info

Publication number: CN209925277U
Application number: CN201920463096.3U
Authority: CN
Inventors: 陆金琪
Original assignee: Shanghai Apollo Machinery Co Ltd
Current assignee: Shanghai Apollo Machinery Co Ltd
Priority date: 2019-04-08
Filing date: 2019-04-08
Publication date: 2020-01-10
Anticipated expiration: 2029-04-08

Abstract

The utility model discloses an axial force balancing device for auxiliary water supply steam-driven pump, which comprises a balancing plate, a balancing plate and a thrust ring, wherein the balancing plate, the balancing plate and the thrust ring are coaxially arranged from front to back in sequence, and the balancing plate is positioned at the rear of a secondary impeller; the rear surface of the balance plate is of a concave structure matched with the conical balance disc; a gap is formed between the balance disc and the balance plate, and an annular surfacing layer is arranged between the balance disc and the balance plate; the thrust ring is fixed on the rear surface of the balance disc through a bolt; the rear part of the balance disc is communicated with the inlet of the auxiliary water supply steam driven pump through a balance water return pipe. The utility model is used for supplementary feedwater steam-driven pump's axial force balancing unit need not set up thrust bearing, has optimized the structure, and the axial force that produces during the operation directly bears by balancing unit, the various operating mode requirements of adaptable pump package operation.

Description

Axial force balancing device for auxiliary water supply steam driven pump

Technical Field

The utility model relates to an axial force balancing unit for assisting feedwater steam-driven pump.

Background

The auxiliary feed water steam-driven pump of the nuclear power plant has the function of providing enough feed water flow to the secondary loop of the steam generator when the main feed water system cannot be used. The auxiliary water supply steam-driven pump belongs to nuclear safety three-level equipment, and each unit of the nuclear power station is provided with two auxiliary water supply steam-driven pumps.

The pump set mainly comprises a pump body, a rotating speed regulating and controlling system, an overspeed protection device, a public base, a water filter, a pressure stabilizing valve, a local control cabinet, a junction box and the like.

The pump is a horizontal two-stage centrifugal pump and is driven by a single-stage back pressure steam turbine; the casing is integrally cast, and the turbine impeller and the pump impeller are arranged on the same shaft; the rotor mainly includes: inducer, primary impeller, secondary impeller, balance disc, turbine impeller, mechanical flyweight and the like. A thrust bearing or a structure of the thrust bearing and a balance disc (balance drum) is adopted on a traditional multistage pump, axial force generated in operation is borne by the thrust bearing, an impeller can generate different axial force under different working conditions, and the thrust bearing can not adapt to various working condition requirements.

SUMMERY OF THE UTILITY MODEL

The utility model aims at overcoming prior art's defect, providing an axial force balancing unit for assisting feedwater steam-driven pump, need not set up thrust bearing, optimized the structure, the axial force that produces during the operation directly bears by balancing unit, the various operating mode requirements of adaptable pump package operation.

The technical scheme for realizing the purpose is as follows: an axial force balancing device for an auxiliary feed water steam-driven pump, the auxiliary feed water steam-driven pump comprises a pump shaft and a rotor, wherein the rotor mainly comprises an inducer, a primary impeller and a secondary impeller; the inducer cover is put in the primary impeller, the primary impeller cover is established on the pump shaft, secondary impeller cover is established on the pump shaft, just secondary impeller is located the rear of primary impeller, axial force balancing unit includes balancing disk, balance plate and thrust ring, wherein:

the balance plate, the balance disc and the thrust ring are coaxially arranged from front to back in sequence, the balance disc is arranged on the pump shaft, and the balance plate and the thrust ring are respectively fixed on a shell of the auxiliary water supply steam-driven pump;

the balance plate is positioned behind the secondary impeller;

the rear surface of the balance plate is of a concave structure matched with the conical balance disc;

a gap exists between the balance disc and the balance plate, an annular surfacing layer is arranged between the balance disc and the balance plate, and the surfacing layer is positioned on the periphery of the gap between the balance disc and the balance plate;

the thrust ring is fixed on the rear surface of the balance disc through a bolt;

the rear part of the balance disc is communicated with the inlet of the auxiliary water supply steam driven pump through a balance water return pipe.

The axial force balancing device for the auxiliary water supply steam-driven pump is characterized in that the thrust ring is made of a non-metal material, and the overlaying layer between the balance disc and the balance plate is formed by stellite alloy overlaying.

The axial force balancing device for the auxiliary water supply steam-driven pump of the utility model has the advantages that the balancing disc and the balancing plate have an axial gap, the pressure difference exists in front of and behind the balancing disc, the stress corresponding to the pressure difference is called as the balancing force, the direction of the balancing force is just opposite to the direction of the axial force, and the axial force generated when the pump impeller runs is balanced by the change of the gap and the balancing force; in this way, a thrust bearing is not needed, the structure is optimized, and the axial force generated in the operation process is directly born by the balancing device and can meet various working condition requirements of the operation of the pump set.

Drawings

FIG. 1 is a structural diagram of an axial force balancing device for an auxiliary feed water pneumatic pump according to the present invention;

fig. 2 is an enlarged schematic view of a gap between the balance disk and the balance plate.

Detailed Description

In order to make the technical solution of the present invention better understood by those skilled in the art, the following detailed description is provided with reference to the accompanying drawings:

referring to fig. 1 and 2, in the preferred embodiment of the present invention, the auxiliary feed steam-driven pump includes a pump shaft 10 and a rotor, the rotor mainly includes an inducer 11, a primary impeller 12 and a secondary impeller 13, the inducer 11 is sleeved in the primary impeller 12, the primary impeller 12 is sleeved on the pump shaft 10, the secondary impeller 13 is sleeved on the pump shaft 10, and the secondary impeller 13 is located behind the primary impeller 12 (using the inlet end of the pump as the sequential reference).

An axial force balancing device for an auxiliary water supply steam-driven pump comprises a balancing disc 1, a balancing plate 2 and a thrust ring 3.

The balance plate 2, the balance disc 1 and the thrust ring 3 are coaxially arranged in sequence from front to back, the balance disc 2 is arranged on the pump shaft 10, and the balance plate 2 and the thrust ring 3 are respectively fixed on a shell of the auxiliary water supply steam-driven pump.

The balance plate 2 is positioned behind the secondary impeller 13; the balance disc 1 is conical, and the rear surface of the balance plate 2 is of a concave structure matched with the conical balance disc 1; a gap 6 exists between the balance disc 1 and the balance plate 2, an annular overlaying layer 4 is arranged between the balance disc 1 and the balance plate 2, and the overlaying layer 4 is positioned on the periphery of the gap 6 between the balance disc 1 and the balance plate 2; the thrust ring 3 is fixed on the rear surface of the balance disc 1 through a bolt, and the rear part of the balance disc 1 is communicated with the inlet of the feed water steam-driven pump through a balance water return pipe. The thrust ring 3 is made of non-metal materials, and the surfacing layer 4 is formed by stellite alloy surfacing.

The utility model is used for supplementary feedwater steam-driven pump's axial force balancing unit, pump package operation, the directional pump import of axial force that the impeller produced, the power that the pressure differential around the balance disk 1 (pressure is big before the balance disk 1, and 2 rear portions of balance disk are equivalent with pump inlet UNICOM through balanced wet return, so pressure and pump inlet pressure) produced is opposite with the axial force. According to the change of the operating condition, the rotor moves back and forth, and the gap between the balance disc 1 and the balance plate 2 is automatically adjusted, so that different axial forces of the impeller under different operating conditions are balanced. In the instantaneous working condition of starting the pump, the axial force points to the rear, a thrust ring 3 is arranged behind the balance disc 1, and the thrust ring 3 is made of non-metallic materials to prevent the balance disc 1 from being meshed with the thrust ring 3; an annular overlaying layer is arranged between the balance disc 1 and the balance plate 2, so that the overflowing scouring resistance is improved, and the two parts can be prevented from being occluded at the same time.

The utility model is used for supplementary feedwater steam-driven pump's axial force balancing unit, when the mill assembly, need control the clearance between balance disc and the balance plate as required. The balance disc and the balance plate have an axial gap, a pressure difference exists between the front and the rear of the balance disc, stress corresponding to the pressure difference is called balance force, the direction of the balance force is just opposite to the direction of the axial force, and the axial force generated when the pump impeller runs is balanced through the change of the gap and the balance force.

Through this a utility model for assisting axial force balancing unit of feedwater steam-driven pump, the pump package no longer sets up thrust bearing, has optimized the structure, guarantees balancing unit's durability through the optimization of material and technology simultaneously.

To sum up, the utility model is used for supplementary feedwater steam-driven pump's axial force balancing unit need not set up thrust bearing, has optimized the structure, and the axial force that produces during the operation directly bears by balancing unit, the various operating mode requirements of adaptable pump package operation.

It should be understood by those skilled in the art that the above embodiments are only used for illustrating the present invention, and not for limiting the present invention, and that the changes and modifications to the above embodiments are within the scope of the claims of the present invention as long as they are within the spirit and scope of the present invention.

Claims

1. An axial force balancing device for an auxiliary feed water steam-driven pump, the auxiliary feed water steam-driven pump comprises a pump shaft and a rotor, wherein the rotor mainly comprises an inducer, a primary impeller and a secondary impeller; the inducer cover is put in the primary impeller, the primary impeller cover is established on the pump shaft, secondary impeller cover is established on the pump shaft, just secondary impeller is located the rear of primary impeller, its characterized in that, axial force balancing unit includes balancing disk, balance plate and thrust ring, wherein:

the balance plate is positioned behind the secondary impeller;

2. The axial force balancing device for auxiliary feedwater steam driven pumps of claim 1, wherein said thrust collar is made of non-metallic material and said overlay between said balance disk and balance plate is stellite.