GB2242933A

GB2242933A - Pot-casing pump

Info

Publication number: GB2242933A
Application number: GB9107289A
Authority: GB
Inventors: Wolfgang Mock
Original assignee: KSB AG; Klein Schanzlin and Becker AG
Current assignee: KSB AG; Klein Schanzlin and Becker AG
Priority date: 1990-04-09
Filing date: 1991-04-08
Publication date: 1991-10-16
Anticipated expiration: 2011-04-08
Also published as: NO911006L; NO177975B; DE4011476C2; GB2242933B; DE4011476A1; NO177975C; GB9107289D0; NO911006D0

Abstract

In a multi-stage pot-casing pump a tubular insert (6) is disposed inside the pot casing (5) to support the stage casings. The tube (6) guarantees the required cohesion for the pump disposed therein and transmits the axial loads which conventionally are transmitted by tie rods or connecting bolts. <IMAGE>

Description

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DESCRIPTION OF INVENTION

Title: "Pot-easing pump'# :2 2 -1 2 e-D 3 =Es THIS INVENTION relates to a multi-stage pot-casing pump, in which the pot casing comprises an intake and a delivery connection and an insert disposed inside the pot casing, the pump being sealingly disposed inside said insert.

As shown by DE-OS 1703529 and 3140392, the pump stages disposed inside a pot casing of a multi-stage potcasing pump are usually held together by tie rods. These structural elements, which are mounted on the pump part externally naturally increase the overall volume and have a negative ef f ect on the f low behaviour within the pot casing. In this connection a construction known f rom DE-AS 2433054 provides flange connections by means of which the pump part is held together. The pump part itself, however, is for this purpose inserted in sealing-tight relationship from above in a complicated insert and is held on the pot casing lid so as to take the forces.

An object of the invention is to develop, for a pot-casing pump, a spacesaving holder with favourable flow characteristics and easy assembly for a centrifugal pump disposed inside a pot.

According to one aspect of the invention there is provided a multi-stage pot-casing pump, in which the pot casing comprises an intake and a delivery connection and an insert disposed inside the pot casing, the pump being sealingly disposed inside said insert, the insert being in the form of a tube which is connected to the pot casing and which transmits axial forces, and in which the tube is 1 2 connected to an inwardly pointing collar in the area of the pot casing base, the pump abutting the collar in forcetransmitting relationship.

The use of the tubular insert according to the invention enables tie rods for holding the pump casing together, or corresponding flange connections, to be dispensed with. The tubular insert accommodates in forcetransmitting relationship the pump inserted into said insert. During assembly, the individual stage casings of the complete pump body are held in their position, for example, solely by the impellers. The pump is then held in position by the insert. The insert itself can be rigidly connected to the pot casing in which case, depending on the pot casing construction, i.e. with an inner or outer lid, and with or without a distributor casing comprising an intake andlor delivery connection, the insert can also be secured on these parts, which should also be considered as parts of the pot casing.

The tube nay be connected to the pot casing, in force transmitting relationship, by an outwardly pointing collar on the tube. Thus the inwardly pointing collar mounted on one end of the tube serves to hold the pump. The outwardly pointing collar of the tube then connects the latter to the pot casing or its similar parts.

According to another aspect of the invention there is provided a multistage pot-casing pump, in which the pot casing comprises an intake and a delivery connection and an insert disposed inside the pot casing, the pump being sealingly disposed inside said insert, the insert being in the f orm of a tube which is connected to the pump and which transmits axial forces, and in which the tube is provided with an inwardly pointing collar in the area of the pot A 3 casing base, the pump abutting against the collar in f orcetransmitting relationship.

In a pump embodying the invention in this aspect, the stage casings are held by the insert and the pump is inserted togethe r with the insert on assembly, into the pot casing or into a lid or a distributor casing connected to the pot casing and comprising an intake and delivery connection. Appropriate biasing of the stage casings against the inwardly pointing collar of the tubular insert or tube is readily possible by means of a lid closing the pot casing.

The tube may be constructed as an interchangeable insert. In this case, the outwardly pointing collar may be mounted at the other end of the tube. This then allows simple fixing within the pot casing. All that is required then is to insert the insert into the pot casing from above and insert into the tube completely the pump stage casings which are disposed loosely in relation to one another and which are held in position by the impellers. The stage casings then bear against the inwardly pointing collar of the tubular insert disposed inside the pot. Thus for the multistage pump part this insert forms a jacket which holds the stage casings in their position. Thus ready assembled and dismantling is guaranteed with minimum complication as a result of the simple insertion and withdrawal.

Embodiments of the invention are described in detail below, by way of example, with reference to the drawings wherein:

FIGURE 1 is a cross-section through a pot pump with a welded-on tubular member and pot.

4 FIGURE 2 shows a construction with a f langed-on pot and FIGURE 3 shows a construction with an inserted tubular member.

Figure 1 shows an exemplified embodiment of a pot casing pump in which the pot casing 1 comprises a distributor casing 4 comprising an intake and delivery connection 2, 3, a pot 5 being welded to the casing 4. Whilst, for convenience of illustration, the pump is shown in Figures 1 to 3 with its axis horizontal, in practice the pump will normally be disposed with its axis vertical and the pump at the lower end of its vertical driving shaft. Terms such as "below" used herein and in the claims refer to this normal orientation of the pump, but it is not intended thereby to limit the scope of the invention to any particular orientation of the pump. The insert, which is f ormed as a tube 6, is welded by one end beneath the delivery connection 3 to the distributor casing 4 and its other end has an inwardly pointing collar 7. In this case the pump 8 is inserted into the distributor casing 4 from above and slides therein and in the tube 6 until it contacts the inwardly pointing collar 7. The individual stage casings are designed to take the pump pressure. The tube is intended only to take the prestressing force holding the pump together and the axial f orces arising f rom the pump delivery pressure. The f orces are in this case transmitted directly to the distributor casing. A lid 9 closing the pot casing 1 holds the pump in position and applies the prestressing forces. The embodiment shown in Figure 2 differs from Figure 1 in that in this case the pot 5 is connected to the distributor casing 4 by a f lange connection 10. Seals 11 prevent pumped medium from f lowing i back from the pre.ssure chamber 12 to the entry 13 to the pump 8.

The embodiment shown in Figure 3 comprises a tube 6 which in this case is constructed as an interchangeable insert. It has an outwardly pointing collar 14 by which it is held inside the distributor casing 4 so as to transmit forces. The insert can equally well be held on a lid closing the pot casing or at some other place than that shown. A throughflow aperture 15 allows pumped medium to pass from the pressure chamber 12 to the delivery connection 3. Elastic elements 16 ensure that the prestress'ing force holding the pump parts together is adequate even under varying states of expansion, such as may occur, for example, in the event of temperature differences. Seals 11, which in this case are constructed as 0-ring seals, ensure appropriate sealing-tightness between the parts.

This construction allows a very small overall volume in pot-casing pumps designed for very high pressures.

The arrangement shown in Figure 3 for example, provides an outlet aperture in the region of the pump end. This is necessary to allow exit from the last pump stage into the delivery connection in the case of a long tubular member extending over the entire pump length. In a short tubular member or one fixed beneath the last stage there is no need for such an outlet aperture. The same applies to the pump entry area. If, for example, there is to be a two-f low single-stage intake here, then appropriate windows can be provided in the tube to allow passage of the pumped medium, for example to a double-flow impeller.

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Claims

1. A multi-stage pot-casing pump, in which the pot casing comprises an intake and a delivery connection and an insert disposed inside the pot casing, the pump being sealingly disposed inside said insert, the insert being in the form of a tube (6) which is connected to the pot casing (1) and which transmits axial forces, and in which the tube (6) is connected to an inwardly pointing collar (7) in the area of the pot casing base, the pump (8) abutting the collar (7) in force-transmitting relationship.

A multi-stage pot-casing pump, in which the pot casing comprises an intake and a delivery connection and an insert disposed inside the pot casing, the pump being sealingly disposed inside said insert, the insert being in the form of a tube (6) which is connected to the pump (8) and which transmits axial forces, and in which the tube (6) is provided with an inwardly pointing collar (7) in the area of the pot casing base, the pump (8) abutting against the collar (7) in force-transmitting relationship.

3. A pot-casing pump according to claim 1, in which the tube is connected to the pot casing (1) in f orcetransmitting relationship by an outwardly pointing collar (14).

4. A pot-casing pump according to claims 1 to 3, in which the tube (6) is constructed as an interchangeable insert (6).

5. A pot casing according to claims 1 to 4 in which a lid (9) closing the pot casing (1) biases the pump (8) against the inwardly pointing collar (7).

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6. A pot-casing pump according to claims 1 to 5, in which elastic elements (16) bias the pump (8) relatively to the inwardly pointing collar (7).

7. A pot-casing pump according to one or more of claims 1 to 6, in which sealing elements (11) are disposed between the interchangeable tubular insert (6) and the distributor casing (4) andlor the pot casing (1).

8. A pot-casing pump according to one or more of claims 1 to 8, in which the tubular insert (6) is provided with passage apertures (15) for the pumped medium.

9. A pot casing pump substantially as hereinbefore described with reference to and as shown in Figure 1 of the accompanying drawings.

10. A pot casing pump substantially as hereinbefore described with reference to and as shown in Figure 2 of the accompanying drawings.

11. A pot casing pump substantially as hereinbef ore described with reference to and as shown in Figure 3 of the accompanying drawings.

12. Any novel feature or described herein.

combination of features Published 1991 at The Patent Office. Concept House. CarditT Road. Newport. Gwent NP9 I RB. Further copies may, be obtained from Sales Branch. Unit 6. Nine Mile Point. Cwrnfelinfach. Cross Keys. Newport. NP1 7HZ. Printed by Multiplex techniques Iltd. St Mary Cray. Kent.