WO1991019904A1

WO1991019904A1 - Rotary fluid pumping apparatus

Info

Publication number: WO1991019904A1
Application number: PCT/AU1991/000259
Authority: WO
Inventors: David Bruce Ogle
Original assignee: Sports Marine International Pty. Ltd.
Priority date: 1990-06-18
Filing date: 1991-06-18
Publication date: 1991-12-26

Abstract

Rotary fluid pumping apparatus suitable for pumping fluids including a mixture of liquids and gases comprises a vaned rotor (12) rotatable about a rotor axis (13) within a pump chamber (11) having an inlet port (16) and an outlet port (17). The pump chamber (11) also includes a chamber portion (14) which is offset from the rotor axis (13) and which is spaced from the tips of the rotor vanes in both an axial and a radial direction. The chamber portion (14) extends about much of the circumference of the pump chamber (11). In operation liquid will tend to be centrifuged towards the outer circumference of the pump chamber (11) and as the outlet port (17) is located some distance from the outer periphery of the pump chamber (11), an annular ring (22) of liquid having an inner boundary (24) will be maintained in the pump chamber (11) for sealing between the rotor (12) and pump chamber (11).

Description

"ROTARY FLUID PUMPING APPARATUS"

This invention relates to rotary fluid pumping apparatus.

This invention has particular but not exclusive applicat to pump apparatus for use in vacuum distillation processes, for illustrative purposes reference will be made to s application. However, it is to be understood that this invent could be used in other applications, such as solvent refining.

The purification of liquids such as water by distillation well-known. The distillation of water conducted at nor pressure requires a substantial heat input at a high temperatu Such processes are therefore considered to be quite wasteful energy.

However, if the pressure within the evaporating vessel reduced, the boiling point of the liquid falls substantial This has two beneficial effects - the heat losses are reduced, it is possible to operate the apparatus utilizing a l temperature heat source.

One particularly useful application of reduced-pressure, vacuum distillation is the production of drinking water from water on a power boat by using the waste heat from the boa engine cooling water. Such distillation apparatus typica comprises a distillation vessel containing a vaporising port into which sea water may be fed and heated, and a condens portion in which water vapour may be condensed to produce pota water. Excess uncondensed vapours, air and other gases usually drawn off the top of the distillation vessel by a vacu pump so as to maintain the desired pressure in the vaporisi portion. Water is also constantly bled from the vaporisi portion to minimise the concentration of salts in the wat contained therein. Hitherto, centrifugal pumps or ejectors have been used pump the vapours, gases and concentrated brine from t distillation vessel. However, centrifugal pumps are not suited the pumping of gases in combination with liquids. Furthermore t performance of centrifugal pumps has been shown to vary great depending on the proportions of gas and liquid handled by t pumps .

As an alternative, side channel pumps of the type commonl referred to as liquid ring pumps, comprising a rotor having plurality of radial, square ended vanes mounted for rotatio within a pump chamber having grooves formed in the side faces o the pump chamber adjacent the ends of the vanes may be used t pump fluids. The rotation of the rotor within the pump chambe induces the rotation of a liquid ring within the outer boundary o the pump chamber including the aforementioned side channels. Th liquid ring provides a seal between the rotor and the walls of th pump chamber. Unfortunately the efficiency of pumps of the typ described is greatly effected by frictional losses associated wit the flow of liquid between the peripheral edges of the vanes an the circumferential wall of the chamber. As an alternative an eccentric liquid ring pump of the typ comprising a pump chamber disposed about a vaned rotor rotatabl about a rotor axis eccentric to the axis of the pump chamber ma be used to pump fluids. The rotation of the rotor induces a fl of liquid within the outer boundary of the pump chamber includi a circumferential groove formed in the circumferential wall of t chamber. Unfortunately the efficiency of pumps of the ty described is greatly effected by frictional losses associated wi the flow of liquid between the side edges of the vanes and t side walls of the pump chamber. The present invention aims to alleviate the abo disadvantages and to provide pump apparatus which will be reliab and efficient in use. Other objects and advantages of th invention will hereinafter become apparent.

With the foregoing and other objects in view, this inventi in one aspect resides broadly in a rotary fluid pumping apparat of the type having a vaned rotor rotatable about a rotor ax within a pump chamber having an inlet port and an outlet port a Whereby a peripheral liquid ring is established within the chamb eccentric to the rotor axis and into which the rotor vanes exte and wherein the ^■swept volume between adjacent vanes of the rot is cyclically increased and decreased, characterised in that sa pump chamber includes a chamber portion offset from said rot axis, said chamber portion being spaced from said rotor in both radial and an axial direction.

The chamber portion preferably extends at least part w about the circumference of the pumping chamber and in o embodiment, may extend outwardly away from the rotor in opposi axial directions.

The vanes may include side portions formed on one or bo sides of the rotor and arranged for interaction with a groove grooves formed in the adjacent side face or faces of the pu chamber. Alternatively, the vanes may include circumferenti portions disposed about the periphery thereof and arranged f interaction with a groove formed in the adjacent circumferenti face of the pump chamber. Preferably, however, the vanes inclu both s_de portions and circumferential portions, and grooves a formed in both the side faces and the circumferential face of t pump casing whereby a pump may be formed having a displaceme which is relatively large in comparison with its size.

In another aspect, this invention resides in a method pumping a mixture of a liquid and a gas, including:- providing a vaned rotor rotatable about a rotor axis; providing a pump chamber disposed about said rotor, sa pump chamber including an inlet port and an outlet port and chamber portion offset from said rotor axis, said chamber porti being spaced from said rotor in both a radial and an axi direction; and installing said rotor within said pump chamber for rotati about said rotor axis such that a fluid or a mixture of liquid a gas may be pumped by rotation of said rotor relative to said pu chamber. ₍

In order that this invention may be more easily understo and put into practical effect, reference will now be made to t accompanying drawings which illustrate a preferred embodiment the invention, wherein:-

FIG. 1 is a front cross-sectional view of a rotary flu pump according to the invention;

FIG. 2 is a front view of the rotor of the pump shown FIG. 1;

FIG. 3 is a top view of the rotor of FIG. 2, and 5 FIG. 4 shows cross-sections through the pump of FIG. 1 various locations around its periphery.

The rotary fluid pump 10 shown in FIGS. 1 to 4 comprises pump chamber 11 within which a rotor 12 is supported for rotati about its rotor axis 13. The interior surface of the pump chamb 10 11 is essentially circular in front cross-section, and the rot ^■ axis 13 is offset from the centre of the casing 11. The interi of the pump chamber 11, viewed from above, is essentially sem circular in cross section, and increases in width proportional with its clearance of the rotor within the chamber portion 14, 15 shown in the cross-sections of FIG. 4. The chamber portion al includes a part circular recess 15 formed in each of the si faces of the pump chamber 11, each recess being offset from t rotor axis 13 in an axial direction as indicated by arrows 2 The pump chamber also includes an inlet port 16 and an outlet po 20 17 formed in a side wall of the casing 11 and wherein the area the inlet port 16 increases circumferentially in the direction rotation of the rotor and the area of the outlet port decreas circumferentially in the direction of rotation of the rotor.

The rotor includes a number of radial vanes 20 each having 25 semi-circular end or tip portion 21 which may cooperate sealab with the pump chamber 11 as illustrated at cross-section F.

In use, the pump 10 has its inlet port 16 connected to vessel in which it is desired to maintain a reduced pressure, a the rotor 12 is arranged to be rotated by a source of mechanic 30 power. The rotation of the rotor 12 induces rotation of a ring of liquid within the chamber portion 14 of the pump chamber 11 a permits the pumping of a fluid within the confines of the cent portion 23 of the rotor 12 between the inlet port 16 and t outlet port 17. The lower boundary of the liquid ring 22 35 shown as a broken line 24 in figures 1 and 4.

Cross-sections of the pump 10 as illustrated in figure detail the shape of the liquid ring 22 and the pumping action various positions "A" to "F" around the circumference of the pu 10. As the rotor 12 rotates from position "F" to position "C" t volume of the chamber portion 14 of the pump chamber 11 increas and the lower boundary 24 of the liquid ring 22 moves toward t tip portions 21 ,of the rotor 12 thereby exposing or opening inl port 16. The fluid being pumped by the pump 10 is according drawn in through the inlet port 16 to fill the expanding volume the centre portion 23 of the rotor 12 created by the recedi lower boundary 24 of the liquid ring 22. As the rotor 12 rotat from position "C" to position "F", the volume of the chamb portion 14 of the: pump chamber 11 decreases and the lower bounda 24 of the liquid ring 22 advances toward the centre portion 23 the rotor 12 thereby forcing the fluid contained in the cent portion 23 through outlet port 17.

Where the fluid being pumped is a mixture of liquid and ga such as concentrated brine and non-condensible vapours and g from a distillation vessel, the liquid will tend to be centrifug toward the outer circumference of the pump chamber 11. As t outlet port 17 is located some distance from the outer periphe of the pump chamber 11, an annular ring 22 of liquid may maintained in the pump, improving sealing between rotor 12 a pump chamber 11 and providing lubrication and cooling for t rotor 12. It will of course be realised that the above has been giv only by way of illustrative example of the present invention a that all such modifications and variations thereto as would apparent to persons skilled in the art are deemed to fall with the broad scope and ambit of this invention as is herein defin in the appended claims.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS.-

1. Rotary fluid pumping apparatus of the type having a van rotor rotatable about a rotor axis within a pump chamber having inlet port and an outlet port and whereby a peripheral liquid ri is established within the chamber eccentric to the rotor axis a into which the rotor vanes extend and wherein the swept volu between adjacent vanes of the rotor is cyclically increased a decreased, characterised in that said pump chamber includes chamber portion offset from said rotor axis, said chamber porti being spaced from said rotor in both a radial and an axi direction.

2. Rotary fluid pumping apparatus as claimed in claim wherein said champer portion extends about a major portion of t circumference of said pump chamber.

3. Rotary fluid pumping apparatus as claimed in claim 1 claim 2, wherein said chamber portion extends outwardly away fr said rotor in opposite axial directions.

4. Rotary fluid pumping apparatus as claimed in claim wherein said chamber portion is part-circular in shape.

5. Rotary fluid pumping apparatus as claimed in any one of t preceeding claims, wherein said rotor is symmetrical about a pla transverse to said rotor axis.

6. Rotary fluid pumping apparatus as claimed in any one of t preceeding claims, wherein said pump chamber is symmetrical abo a plane transverse to said rotor axis.

7. Rotary fluid pumping apparatus as claimed in any one of t preceeding claims, wherein said pump chamber is substantial symmetrical about a plane containing said rotor axis and sa inlet and outlet ports are positioned on opposite sides of t plane containing said rotor axis and wherein the area of sa inlet port increases circumferentially in the direction rotation of said rotor and the area of said outlet port decreas circumferentially in the direction of rotation of said rotor.

8. Rotary fluid pumping apparatus as claimed in any one of t preceeding claims, wherein the tip portions of said vanes of sa rotor cooperate sealably with said pump chamber.

9. Rotary fluid pumping apparatus including:- a vaned rotor rotatable about a rotor axis; a pump chamber disposed about said rotor, said pump chamb including an inlet port, an outlet port and a chamber porti offset from said rotor axis, said chamber portion being spac from said rotor in both a radial and an axial direction.

10. A method of pumping a fluid such as a mixture of a liqu and a gas, including:- providing a vaned rotor rotatable about a rotor axis; providing a pump chamber disposed about said rotor, sa pump chamber including an inlet port and an outlet port and chamber portion offset from said rotor axis, said chamber porti being spaced from said rotor in both a radial and an axi direction; and installing said rotor within said pump chamber for rotati about said rotor axis such that a fluid may be pumped by rotati of said rotor relative to said pump chamber.

11. Rotary fluid pumping apparatus substantially as hereinbefo described with reference to the accompanying drawings.