GB1575991A

GB1575991A - Pump such as a barrel pump

Info

Publication number: GB1575991A
Application number: GB4372/78A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-11-14
Filing date: 1978-02-03
Publication date: 1980-10-01
Also published as: FR2408740B3; CH628116A5; JPS5469805A; FR2408740A1; ES473155A1; DE2750801A1; DE2750801C2; SE7800780L

Abstract

The liquid is pumped by a pump rotor (6) through an annular duct (4) upwards to an outlet (5). Not far above the rotor (6), a leakage duct (21) emanating from a supporting tube (2) surrounding a rotor shaft (7) is passed through the annular duct (4) in a sealed manner. Leakage fluid from the supporting tube (2) can thus be returned to the supply of liquid within a container, e.g. a drum, so that any contamination of the supply is avoided. <IMAGE>

Description

(54) A PUMP, SUCH AS A BARREL PUMP (71) We, KARL LUTZ, a Company (EINZELFIRMA) organised under the laws of the Federal Republic of Germany, of Erlenstrasse 5-7, 6980 Wertheim 2, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a pump, such as a barrel pump, having a pump rotor which is driven by way of a rotor shaft by a motor, e.g.

an electric or compressed air motor, by means of which rotor the fluid is pumped up in an annular passage, located between a supporting tube for the rotor shaft and a tubular casing, to an outlet which is connected to the annular passage, and having at least one drain passage which serves to carry away any fluid that has leaked into the supporting tube.

The term "barrel pump" is used in this specification to mean a pump intended for emptying a barrel or like container containing a fluid by inserting the pump through an opening in the barrel top so that it rests on the barrel bottom, the pump outlet remaining outside the barrel. Thus, for this purpose, the pump is relatively long as compared with its width and the pump drive motor is situated at the top end of the pump. Obviously the pump has other uses and it is not intended to limit the invention to this particular application or construction.

In a known pump of this type the drain passage for the leakage is provided above the outlet and below the rotor shaft bearing and the coupling for the rotor shaft with the electric motor. The drain passage for the seepage is thus located in an area above the outlet connecting pipe of the pump, which pipe is already located outside the container from which the fluid is being pumped out. When leakage occurs there is the danger that it does not pass back again into the container and thus lead to contamination which is to be avoided. An escape of fluid near to the container is particularly to be avoided in the case of corrosive fluids which could lead to the operating personnel being endangered.

A bore-hole pump is known which in theory could be of such dimensions that it could be used as a barrel pump and in which the leakage could flow back into the container far below the outlet so that the danger of an escape of seepage outside the container would be avoided. This pump has, however, a feed tube whose cross-section above the bearing associated with the rotor deviates from a circular cross-section and in fact is substantially C-shaped cross-section, the outer wall up to a small section being circular, whilst the inner wall is guided about the overhung pump rotor so that a laterally open chamber for the rotor shaft is formed in which the fluid is not fed.This possible development would avoid contaminating the environment of the container from which the fluid was to be pumped as the leakage opening is located within the fluid or at least within the container, but the production of the feed tube is extraordinarily complicated as it would be necessary to manufacture a cross-section which deviates from the circular cross-section, whereby support bearings for the rotor shaft would still have to be provided in the laterally open chamber.

An object of the invention is to construct a pump of the type mentioned initially so that despite the retention of the annular passage for conveying the fluid, it is possible to carry away leakage fluid and to retain the leakage fluid within the container from which the fluid is being pumped.

In accordance with the invention there is provided a pump in which a rotor is driven by a shaft mounted for rotation in a support tube surrounded by a tubular casing to define an annular passage whereby fluid entering the casing in the region of the rotor may be pumped through the annular passage to be discharged through an outlet opening provided in the casing at a location displaced from the rotor in the direction of the casing axis, and in which the interior of the support tube is connected to the exterior of the tubular casing by at least one drain passage extending across the annular passage and passing through the casing to a location which is nearer to the rotor than the said outlet opening.

By means of the arrangement of the drain passage which is guided through the annular passage in a sealed manner, the seepage into the supporting tube can be carried away through the annular passage to the outside, without the fluid pressure in the annular passage being able to exert any influence thereon. As a flow-favourable cross-section can be used for the drain passage for the flow direction of the fluid in the annular passage, the impairment of the flow of the fluid in the annular passage is negligibly small.

In order to avoid the seepage within the supporting tube being subjected to any unnecessary delivery head, it is advantageous for the drain passage to be provided directly above the bearing associated with the pump rotor.

A first possibility of providing a drain passage in a pump in accordance with the invention resides in forming each drain passage by a tube which is inserted in a sealed manner between the supporting tube and the tubular casing and which encircles an opening in the supporting tube and an opening in the tubular casing. This construction is also suitable for the conversion of already existing pumps in which the tubular casing and the supporting tube are bored and an appropriately adapted tube piece is welded in between the supporting tube and the tubular casing, whereby the tube piece inserted encloses the bores provided and produces a connection between the interior of the supporting tube and the exterior of the tubular casing. By welding-in the tube piece the interior of the supporting tube is sealed relative to the annular passage.Likewise the external environment outside the tubular casing is sealed relative to the annular passage.

Another advantageous development of the invention consists in forming each drain passage by a hollow guide blade or vane which is disposed radially in the annular passage above the pump rotor and connects the supporting tube to the tubular casing. These guide blades are disposed equi-angularly spaced when viewed in plan to form an assembly sometimes described as a "guide star" or "spider" serve on the one hand to align the the circulating components of the fluid conveyed in the direction of the rotor shaft and on the other hand, to maintain a uniform spacing between the tubular casing and the supporting tube, can at least partially be provided with passages so that additional drain passages can be dispensed with.Any impairment of the flow within the annular passage is thus excluded, if one disregards the fact that the guide blades, constructed as drain passages, are made somewhat thicker than the guide blades which are not hollow.

A further development of the invention consists in inserting a guide star having at least one hollow guide blade which serves as a drain passage into the interior of the tubular casing and which has a tubular core constructed to receive the tube ends of a supporting tube divided by the tubular core. The assembly of the pump thereby takes place in such a manner that the supporting tube is constructed so as to be divided, whereby after the installation of the upper part of the supporting tube, the guide star is introduced into the interior of the tubular casing and is inserted so that the hollow guide blade of the guide star aligns with a bore in the tubular casing and the lower end of the upper section of the supporting tube engages in the tubular core of the guide star.In this position the guide star is welded to the tubular casing from outside through the opening in the tubular casing and then the lower section of the supporting tube is inserted. The tubular core of the guide star thus replaces a short section the supporting tube and the two supporting tube sections on each side of the guide star are connected to each other.

A particularly advantageous simplification of the design of a pump results if in a further development of the invention a bearing head is provided at the lower end of the pump and comprises two coaxially disposed tube pieces, of which the inner tube piece can be connected to the supporting tube to extend the supporting tube and the outer tube piece can be connected to the tubular casing to extend the tubular casing, the two pieces being firmly connected to each other at least by a hollow guide blade, the part of the inner tube piece which is located between the hollow guide blade and the pump rotor being provided with a sealing and bearing unit.

This development has the advantage that it here relates to a combined bearing head and leakage drain head which is manufactured from a single part and can be mounted at the lower end of the supporting tube and of the tubular casing, i.e. at the lower end of the annular passage, by means of which the pump is completed below. This substantially simplifies the manufacture of a drain passage so that it no longer has to be inserted into the annular passage between the supporting tube and the tubular casing and welded to these tubes.

The connection between the outer tube piece and the tubular casing, can for example, be achieved by means of a screw thread whilst the inner tube piece can be connected to the supporting tube by means of a simple plug connection, i.e. by inserting the supporting tube into the inner tube piece or by inserting the inner tube piece into the supporting tube.

A particular simplification in the design of the pump is achieved in accordance with a further advantageous feature of the invention by means of a plastics tube which is inserted between the rotor shaft and the supporting tube, and serves to support the rotor shaft and consists preferably of polytetrafluoroethylene. The arrangement of such a plastics tube, which is inserted simply prior to mounting the head bearing between the supporting tube and the rotor shaft, has the advantage that the expenditure on assembly is extremely low. This is particularly clear when one compares the insertion of the plastics tube with the mounting of support bearings which have to be provided because of the great length of the rotor shaft. This plastics tube replaces the support bearings.As this plastics tube can under certain circumstances be made so long that it substantially overlaps the entire length of the rotor shaft, it is not necessary for the tolerances in size to be kept within narrow limits as is the case in the arrangement of support bearings, as the long shaft can be supported over a very great area so that its support by the plastics tube is better, even when the clearance is greater, owing to the great length, than is the case with the relatively short support bearings. If a suitable material is used, such as, for example, polytetrafluoroethylene, then any lubricant can be dispensed with, which could contaminate the fluid to be pumped.

The use of a one-piece bearing head, as described above, brings with it further advantages. Thus it is possible, for example, to provide a pump base which surrounds the pump rotor. In this development of the invention the outer tube piece carries at the end associated with the pump rotor, a pipe socket which accommodates within it the pump rotor and is provided with recesses and is either produced as one piece with the outer tube piece or is detachably connected thereto.

Embodiments of the invention are hereinafter described, by way of example, with reference to the accompanying draw ings, in which: Figure 1 is a longitudinal section through a pump tube set of a barrel pump; Figure 2 is a section along the line II-II in Figure 1; Figure 3 is an external view of the lower part of the pump tube set of Figure 1; Figure 4 is a section through a somewhat modified embodiment of the pump tube set of Figure 1; Figure 5 is a section through another embodiment of a pump tube set in accordance with the invention; Figure 6 is a section along the line VI-VI in Figure 5; Figure 7 is a partial sectioned view along the line VII-VII in Figure 6; Figure 8 is a section through a further embodiment of a pump tube set in accordance with the invention; and Figure 9 is a section along the line IX-IX in Figure 8.

For each embodiment, the drawings show only the fluid-conveying part of the pump without the drive motor as the representation of the drive motor is not required in order to understand the invention. For convenience, this part of the pump is termed a pump tube set.

The pump tube set which is denoted as a whole by 1 in Figure 1 comprises a supporting tube 2 and a tubular casing 3 which enclose between them an annular passage 4.

The fluid is pumped up through the annular passage 4 to an outlet 5 by means of a pump rotor 6 which is seated at the lower end of a pump drive shaft 7. The drive shaft 7 extends within the supporting tube and is provided at its upper end with a coupling 8 by means of which it can be connected to a drive motor (not shown). The supporting tube 2 and the tubular casing 3 are interconnected at their upper ends by welding to a bearing housing 9 which accommodates roller bearings 10 to support the rotor shaft 7. A retaining nut or cap 11 is rotatably mounted relative to the bearing housing 9 and has an inner thread 12 which can be screwed onto a corresponding outer thread on the drive motor (not shown) by means of which the pump tube set 1 with the rotor shaft 7 is secured to the drive motor.

At the lower end of the supporting tube 2 and the tubular casing 3 a bearing head which is denoted in its entirety by 13 is provided and has an inner tube piece 14 and an outer tube piece 15 which are connected to each other by means of two solid guide blades 16 and two hollow guide blades 17 which are disposed radially in alignment with each other. The inner tube piece 14 has in its upper part 14a, which extends to the guide blades 16 and 17, an inside diameter which is substantially adapted to the outer diameter of the supporting tube 2 so that the tube 2 can be tightly introduced into the inner tube piece 14.The upper part l5a of the tube piece 15, which also extends to the guide blades 16 and 17, is provided with an internal thread 18 by means of which the outer tube piece and thus the entire bearing head 13 can be screwed onto the tubular casing 3 which has in its lower region an external thread 19 corresponding to the internal thread 18. The threads 18 and 19, connected to each other, can be provided additionally with a sealing means in the event that the thread connection is not fluid-tight. A seal gasket is not necessary between the upper part 14a of the inner tube piece 14 and the supporting tube 2 as no fluid pressure, deriving from the action of the pump rotor, can build up in this chamber because of the arrangement of a drain passage which has still to be described in detail.In this area the fluid can stand only as high as corresponds to the fluid level in the container into which the pump tube set is inserted.

A plastics tube 20, consisting preferably of polytetrafluoroethylene, is inserted between the supporting tube 2 and the rotor shaft 7.

This tube serves to support the rotor shaft 7 relative to the supporting tube 2 and thus takes over a bearing function.

The hollow guide blades 17 connect the interior of the inner tube piece 14 and thus the interior of the supporting tube 2 to the exterior of the outer tube piece 15 by means of drain passages 21 which form the cavity of these hollow guide blades 17. By means of these drain passages 21 fluid which has penetrated or leaked into the interior of the supporting tube 2 can flow away again to the outside. The passages 21 thus make it possible to have in the interior of the supporting tube 2 a fluid pressure which corresponds to that of the fluid in the container from which the fluid is being pumped.

Sealing and bearing inserts 22 are provided in the lower part 14b of the inner tube piece 14 and serve on the one hand to support the rotor shaft 7 at its lower end and on the other hand as a seal against any entry of fluid. Thus, the lower part 14b, in effect, forms the lower part of the tube 2. The fluid which climbs upwards along the shaft despite these inserts passes into the drain passages 21 of the hollow guide blades and is thereby carried away again. The guide blades 16 and 17 serve to align the flow of the fluid which is forced into the annular passage 4 by the pump rotor 6 and has a circulatory movement component.

An external thread 23 is provided at the lower part 15b of the outer tube piece 15, onto which can be screwed a projection 24, serving as a pump base, which surrounds the pump rotor 6 and is provided with recesses 25 through which the fluid can pass to the pump rotor 6. This pump base 24 extends below the pump rotor 6 so that the pump with this pump base can be set up on the base of the vessel. Moreover it forms a protective covering for the pump rotor 6.

In the embodiment in Figure 4 a bearing head 113 is provided which except for a slight alteration corresponds to the bearing head 13 of the embodiment in Figures 1 to 3. The alteration consists in that the upper part 1 14a of the inner tube piece 114 has a cylindrical outer wall of a somewhat smaller outer diameter than the upper part 14a of the bearing head 13. Furthermore this upper part 1 14a is longer than the part 14a in the case of the bearing-head 13. In the embodiment in Figure 4 the upper part 1 14a is introduced into the interior of the supporting tube 102 which has a larger inner diameter than the supporting tube 2 of the embodiment in Figures 1 to 3.For this reason the plastics tube 120, provided between the supporting tube 102 and the rotor shaft 107, has thicker wall in order to fill up the larger space between the rotor shaft 107 and the supporting tube 102.

In the embodiment in Figures 5 to 7 a different construction for the discharge of the leakage is provided as compared with the embodiment of Figures 1 to 4. As can be seen from Figures 5 to 7, a fluid flow guide insert or guide star 226 is secured in the interior of the tubular casing 203 and has four guide blades, of which two guide blades, provided with the reference numeral 216, are solid guide blades whilst the other two guide blades, denoted by 217, are hollow to provide have drain passages 221 which connect the interior of the guide star, which is surrounded by a tubular core 214, to the exterior of the tubular casing 203.

The guide star 226, which is constructed as an insertable component, has sockets 227 at the two outer ends of the tubular core 214.

The supporting tube 202 is divided and the ends of the divided supporting tube 202 can be introduced into the sockets 227. The guide star is thus inserted between two parts of the supporting tube and connected to the outer tubular casing 203 by means of welding seams 228 made at the periphery of openings 229 in the tubular casing 203. The openings 229 are in such a position that, after inserting the guide star 226 into the casing 203, the openings align with the drain passages 221.

In the embodiment shown in Figures 5 to 7 a guide vane arrangement 230 is provided in the lower area of the tubular casing 203 and has guide vanes, disposed at an angle to the rotor shaft 207, which serve the purpose of imposing an opposite direction of flow on the fluid which circulates with a helical twist from the rotor 206 so that after leaving the guide vane arrangement 230 the fluid flows substantially parallel to the rotor axis, i.e. it flows substantially free from any twist in the annular passage 204.

Figures 8 and 9 show an embodiment which is suitable for a simple conversion of an already existing pump. In this embodiment the guide star 226 of the embodiment of Figures 5 to 7 is replaced by a simple tube 231 which is inserted between the supporting tube 202 and the tubular casing 203 and is welded to these two parts. The tube 231 encircles an opening 232 in the supporting tube and an opening 233 in the tubular casing 203. The interior of the supporting tube 202 is thus connected by way of the tube 231 to the exterior of the tubular casing 203.

In Figures 4 to 9 all the parts which correspond to those in Figures 1 to 3 are provided with the same reference numerals, raised by 100 in Figure 4 and 200 in Figures 5 to 9 and for this reason are not described in any more particular detail.

WHAT WE CLAIM IS: 1. A pump in which a rotor is driven by a shaft mounted for rotation in a support tube surrounded by a tubular casing to define an annular passage whereby fluid entering the casing in the region of the rotor may be pumped through the annular passage to be discharged through an outlet opening provided in the casing at a location displaced from the rotor in the direction of the casing axis, and in which the interior of the support tube is connected to the exterior of the tubular casing by at least one drain passage extending across the annular passage and passing through the casing at a location which is nearer to the rotor than the said outlet opening.

2. A pump in accordance with claim 1 which is of generally elongate shape and is intended for use with its axis approximately vertical for emptying a container, the rotor being located near the bottom end of the casing and the outlet opening near the top end, and in which a drive motor for the shaft is secured to the top end of the casing.

3. A pump in accordance with claim 1 or claim 2 in which the or each drain passage is provided directly adjacent a bearing associated with that end of the drive shaft connected to the rotor.

4. A pump in accordance with any preceding claim in which the or each drain passage is formed by a tube which is inserted in a sealed manner between the support tube and the casing and which encircles an opening in the support tube and an opening in the casing.

5. A pump in accordance with any one of claims 1 to 3 in which the or each drain passage is formed by a guide blade which is constructed so as to be hollow and is disposed radially in the annular passage downstream of the pump rotor and connects the support tube to the casing.

6. A pump in accordance with claim 5, in which an insert having at least one hollow guide blade which serves as a drain passage is inserted into the interior of the casing and has a tubular core which is constructed to receive the opposed ends of a divided support tube.

7. A pump in accordance with claim 5 in which a bearing head is provided at the lower end of the pump and comprises two coaxially disposed tube pieces of which the inner tube piece is connected to the support tube to extend the support tube and the outer tube piece is connected to the casing to extend the casing the two tube pieces being firmly connected to each other at least by one hollow guide blade, and the part of the inner tube piece which is located between the hollow guide blade and the pump rotor being provided with a bearing insert.

8. A pump in accordance with any preceding claim in which a plastics tube is inserted between the rotor shaft and the support tube and serves to support the rotor shaft.

9. A pump in accordance with claim 8, in which the plastics tube consists of polytetrafluoroethylene.

10. A pump in accordance with claim 7, 8, or 9, in which the outer tube piece carries at its lower end associated with the pump rotor a cylindrical projection which accommodates within it the pump rotor and is provided with fluid-entry recesses, and the projection is either produced as one piece with the outer tube piece or is detachably connected thereto.

11. A pump substantially as hereinbefore described with reference to, and as illustrated in, Figures 1 to 3, or Figure 4, or Figures 5 to 7, or Figures 8 and 9, of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. 203. The interior of the supporting tube 202 is thus connected by way of the tube 231 to the exterior of the tubular casing 203. In Figures 4 to 9 all the parts which correspond to those in Figures 1 to 3 are provided with the same reference numerals, raised by 100 in Figure 4 and 200 in Figures 5 to 9 and for this reason are not described in any more particular detail. WHAT WE CLAIM IS:

1. A pump in which a rotor is driven by a shaft mounted for rotation in a support tube surrounded by a tubular casing to define an annular passage whereby fluid entering the casing in the region of the rotor may be pumped through the annular passage to be discharged through an outlet opening provided in the casing at a location displaced from the rotor in the direction of the casing axis, and in which the interior of the support tube is connected to the exterior of the tubular casing by at least one drain passage extending across the annular passage and passing through the casing at a location which is nearer to the rotor than the said outlet opening.