Multi-stage centrifugal pump

Patent metadata

Field	Value
Publication number	US-2016108922-A1
Application number	US-201514882750-A
Country	US
Kind code	A1
Filing date	Oct 14, 2015
Priority date	Oct 15, 2014
Publication date	Apr 21, 2016
Grant date	—

Abstract

A multistage centrifugal pump includes a foot part ( 1 ) and a head part ( 7 ), between which several pump stages are arranged. Each of the pump stages includes an impeller ( 4 ) and a housing ( 5 ) surrounding the impeller ( 4 ). The housings ( 5 ) are arranged over one another. The housings ( 5 ) together with an outer casing ( 9 ) form an annular channel ( 8 ). The housings ( 5 ) together with an outer casing ( 9 ) are clamped via clamping bolts ( 11 ) which are fastened on the head part ( 7 ) and the foot part ( 1 ). The clamping bolts ( 11 ) are arranged within the annular channel ( 8 ).

First claim

What is claimed is:

1 . A multi-stage centrifugal pump comprising:
a foot part comprising a suction connection and a delivery connection; a head part; at least two pump stages are arranged between the foot part and the head part, said stages each comprising an impeller and a housing surrounding the impeller; an outer casing surrounding each housing at a distance and forming an annular channel; clamping bolts connecting the head part and the foot part to one another amid the inclusion of the casing and the housings, wherein the annular channel leads the delivery fluid to one of the connections, wherein the clamping bolts are arranged in the annular channel.

2 . A centrifugal pump according to claim 1 , wherein the annular channel fluidically connects a delivery-side exit of at least one of the pump stages to a delivery connection of the pump.

3 . A centrifugal pump according to claim 1 , wherein the annular channel fluidically connects a suction connection of the pump to a suction entry of at least one of the pump stages.

4 . A centrifugal pump according to claim 1 , wherein the clamping bolts are arranged spaced apart at a same angular distance in the annular channel.

5 . A centrifugal pump according to claim 1 , wherein the clamping bolts are each arranged radially centrally between the inner side of the outer casing and the outer sides of the housing.

6 . A centrifugal pump according to claim 1 , wherein the clamping bolts are provided with an outer thread at least at one end.

7 . A centrifugal pump according to claim 6 , wherein the clamping bolts are provided with an inner thread and, on the foot part side or on the head part side, are each fastened in one of a plurality of bores.

8 . A centrifugal pump according to claim 7 , wherein:
the bores are though-bores; and the clamping bolts on the head part side or foot part side are led up to/through the through-bores in the head part or foot part and are fastened by nuts.

9 . A centrifugal pump according to claim 1 , further comprising a seal provided at least one of between the clamping bolt and the head part and between the clamping bolt and the foot part.

10 . A centrifugal pump according to claim 9 , wherein:
the seal is an O-ring arranged between the clamping bolt and the through-bore; and the clamping bolt is thread-free in the region of the seal.

11 . A centrifugal pump according to claim 10 , wherein an O-ring seat is formed on the clamping bolt, the seat comprising a first contact shoulder which is formed by a first ring fixed in a groove on the clamping bolt and with a second contact shoulder formed by a second ring having a second ring inner thread and which is fixed on a threaded section of the clamping bolt.

12 . A centrifugal pump according to claim 1 , wherein cap nuts, each comprising a collar projecting radially beyond a through-bore, as well as a peripheral groove in the region of the through-bore, form a seal seat for an O-ring.

13 . A centrifugal pump according to claim 1 , wherein a seal seat for an O-ring is formed by a ring which with an inner thread, the ring being fixed on a threaded section of the clamping bolt, in combination with a peripheral groove in an associated through-bore.

14 . A centrifugal pump according to claim 1 , wherein a seal seat is formed by the part of a through-bore which is widened in a stepped manner, in combination with a covered washer.

15 . A centrifugal pump according to claim 1 , wherein each clamping bolt is constructed in a two-part or multi-part manner, from clamping bolt sections which are connected to one another by way of thread connections.

16 . A centrifugal pump according to claim 1 , wherein a ratio of surface areas, which are pressure-effective for the loading of the clamping bolts and which are loaded by an exit pressure of the pump and by an entry pressure of the pump, is at least two.

17 . A centrifugal pump according to claim 1 , wherein the clamping bolts are arranged within the annular channel form a type of guidance for the delivery fluid.

Assignees

• Grundfos Holding As

Inventors

• Mikkelsen Steen
• Danielsen Carl-Christian

Classifications

• F04D29/628

  especially adapted for liquid pumps · CPC title

• F04D1/063 Primary

  of the vertically split casing type · CPC title

• F04D13/021

  containing a coupling · CPC title

• F04D29/426

  especially adapted for liquid pumps · CPC title

• F04D17/12 Primary

  Multi-stage pumps · CPC title