AU607079B2

AU607079B2 - Pneumatic device

Info

Publication number: AU607079B2
Application number: AU37279/89A
Authority: AU
Inventors: John Stanley Melbourne
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-09-12
Filing date: 1989-06-30
Publication date: 1991-02-21
Anticipated expiration: 2009-06-30
Also published as: AU3727989A

Description

PHILLIPS ORMONDE AND FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne, Australia P17/2/83 AUSTRALIA6A Patents Act I'f 0' COMPLETE SPECIFICATION

(ORIGINAL)

Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Int. Class 0 0 C Related Art: 4

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APPLICANT'S REF.: CAP of PJ0359

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Name(s) of Applicant(s): Address(es) of Applicant(s): Actual Inventor(s): JOHN STANLEY Mi' 1 iOURNE 2/413 Dorset Road, Boronia, Victoria 3155, Australia John Stanley Melbourne 0i 1 0411 30O68 39 PHILLIPS, ORMONDE AND FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne, Australia, 3000 Address for Service is: Complete Specification for the invention entitled: "PNEUMATIC DEVICE" The following statement is a full description of this invention, including the best method of performing it known to ,applicant(s): P19/3/84 I 1 re I t P C C Ct C CCC Cr iC

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This invention relates to an improved air mover or air pump.

One form of pneumatic device, referred to as either an air mover or air pump, has an elongate tubular body defining a through bore. Between the ends of the bore, the body or a fitting secured thereto, defines an annular chamber which extends substantially concentrically around the bore. Pressurised air is able to be supplied to the chamber for discharge via a plurality of passages providing communication between chamber and the bore; the passages opening towards one end of the bore such that the discharged air issues from that end. The pressurised air generates a reduction in pressure upstream of the bore from the passages, such that air is able to be drawn along the bore. The device functions either as an air mover or an air pump and can be used for example for vacuum generation, to transport particulate material, and to purge gases from or to supply gas to an enclosure or work area. Typically, the passages providing communication between the chamber and bore extend substantially parallel to the axis of the bore, or they are inclined toward the bore so as to converge at an axial location downstream of the chamber.

The present invention is directed to providing an improved pneumatic device of the above type.

In a device according to the invention, the communication between the pressurised gas receiving chamber and the bore is provided by passages which are inclined both radially inwardly towards and transversely 30 with respect to the axis of the bore. All passages, in a circumferential array, are similarly inclined. Most conveniently, the respective inclinations of jets of air issuing into the bore from the chamber together define a flow of air which, extending axially from the chamber, at first converges as if along a frusto-conical surface and thereafter diverges as if along a similar frusto-conical path. The jets thus converge downstream of the chamber to define a throat of reducing cross-section, down to a 39 minimum cross-section, and thereafter diverge outwardly.

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00 1 4950F C Li 4$ 4 $4 o 4 04 6o 4 u a r o *ool o 0 o o 0 04 00 0 oo The jets, because of their inclination transversely with respect to the axis of the bore tend to impart a spiral path. Most conveniently, the flow of gas into the chamber is tangential with respect to the bore, to generate an annular flow in the chamber. In such case, the inclination of the passages transversely with respect to the axis of the bore is in a direction such that the air flows into the passages in part as a continuation of the annular flow in the chamber. That is, the direction of transverse inclination of the passages is such that, in flow along the passages, the air has a component of its flow which is in the same circumferential direction as the flow of air in the chamber.

Upstream of the chamber, the housing of the device preferably is defined by an inlet nozzle which increases in diameter away from the chamber. This is appropriate where the device is for use as an air mover, rather than as an air pump. Along its axial extent, the increase in diameter preferably is by the nozzle being belled so as to smoothly flare outwardly. The nozzle most preferably is so flared with a radius of curvature in excess of the radius of the bore adjacent the chamber; the radius of curvature preferably exceeding that radius of the bore by a factor of from 1.2 to 1.6.

Downstream of the chamber, the housing of the device may be substantially cylindrical. Alternatively, that portion of the housing may be slightly flared, such as to increase in diameter away from the chamber. Such increase in diameter may be uniform, such as at an angle of from 30 50 to 100 to the axis of the bore.

Reference now is directed to the accompanying drawings, in which: Figure 1 is an end elevation of a device according to the invention; Figure 2 is a sectional view taken on line II-II of Figure 1; and Figure 3 is a perspective view of a component of the device of Figures 1 and 2, with a schematic representation 39 of air flow generated by the component.

0040 Da O 0 0 0404 4950F -3- The device 10 has an inlet nozzle 12 coupled to an outlet duct 14 by means of an annular hub member 16. Duct 14 is threaded (but may be welded) within one end of member 16, with a resilient O-ring 18 providing a seal therebetween, Nozzle 12 and member 16 are bolted together at overlapping projections 20, with an O-ring 22 providing a seal therebetween.

Within member 16, and between nozzle 12 and duct 14, there is provide an annular ring member 24. Respective O-rings 26,28 provide a seal between member 24 and each of nozzle 12 and member 16. An annular chamber 30 is defined by nozzle 12 and members 16,24, with chamber 30 extending substantially concentrically around bore 32 defined by nozzle 12, member 24 and outlet 14.

«As shown in Figure 1, an inlet port 34 for chamber is provided in hub member 16. Port 34 enter tangentially with respect to chamber 30 and bore 32. Port 32 is connectable to a source of pressurized gas, such as S" air or steam, with gas supplied to chamber 30 being caused to flow circumferentially around chamber 30 prior to discharge therefrom.

The inner circumference of member 24 adjacent nozzle 12 provides a smooth continuation of the inner surface of nozzle 12. However, downstream of nozzle 12, member 24 is stepped to define a shoulder 36 which faces the portion of bore 32 within duct 14. Beyond shoulder 36, member 24 has a frusto-conical internal surface portion 38 which merges, via a similar surface portion 40 of member 16 with the o° internal surface of duct 14. The outer circumferential 30 surface of member 24 is stepped to define a shoulder 42 which faces oppositely with respect to shoulder 36, and a plurality of circumferentially disposed passageways 44 are defined in member 24, between shoulders 36,42, to enable gas supplied to chamber 30 to discharge under pressure into bore 32 within duct 24.

Passageways 44 are inclined toward the axis of bore 32 within duct 14, such as at an angle of from 20 to such as from 3° to 15°, preferably from 3° to 39 10° such as from 5° to 10°. However, the outlet of 4950F -4r passageways 44 at shoulder 36 are displaced circumferentially with respect to their inlets at shoulder 42, in the direction of flow of gas in chamber 30, such that passageways also are inclined transversely with respect to the axis of bore 32 in duct 14. The inclination of passageways 44 transversely with respect to that axis may be at an angle of up to 200, such as from 3 to 20o; preferably at an angle of from 4 to i 150, such as from 50 to Ring member 24 is shown in perspective in Figure 3, while lines 46 represent the flow of gas from passageways i 44 in duct 14 as if maintained as narrow streams of gas.

The streams 46 of gas at first converge frusto-conically toward the axis of bore but, at a region within duct 14 downstream of member 24 and shown at A in Figure 3, they thereafter diverge frusto-conically outwardly toward the internal surface of duct 14. Such convergence, and then divergence is due to the inclination of passageways 44 both toward, and laterally with respect to, the axis of bore 32 within duct 14.

As with the prior devices, the streams of gas issuing from passageways 44 give rise to a reduction of pressure within a zone of bore 32, upstream of member 24.

However, that zone also extends within duct 14 in the portion thereof in which the streams of gas are converging frusto-conically. The device therefore is able to provide suction at the inlet of nozzle 12, by which the device is able to generate a vacuum, or to draw air or other gas into nozzle 12 for discharge along duct 14. Device thus is able to function as an air mover or air pump but, due to the strong flow pattern generated in duct 14 by gas passing from chamber 30 through passageways 44, device provides greater efficiency of operation than prior devices.

In Figure 2, only part of the length of duct 14 is shown, while duct 14 is shown as being of cylindrical form. The length of duct 14 preferably is related to the inclination of passageways 44, such that streams 46 are 39 able to diverge frusto-conically outwardly to a 4950F

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C'1 C C cross-section approximately equal to that of bore 32 adjacent the downstream end of duct 14. However, instead of being cylindrical, duct 14 may diverge outwardly toward its downstream enC to increase the extent to which streams 46 can diverge within a duct 14 of given length. Such divergence of duct 14 may be frusto-conical, or it may be belled outwardly in a sense opposite to that shown for nozzle 12. For a frusto-conical duct 14, the divergence preferably is at an angle of not more than 150; while duct 14 preferably has an axial extent which is at least ten times, most preferably at least fifteen times that of nozzle 12. Where nozzle 14 is belled, it preferably is flared outwardly over a radius of curvature which is at least three times the minimum radius of bore 32 in duct 14.

While nozzle 12 is shown as a smoothly curved, belled configuration, as is preferred, it may be frusto-conical overall or have a frusto-conical portion adjacent members 16,24.

Streams 46 are shown as if they remain as a linear 20 extension of passageways 44. While this is schematic, such linear flow is partially assisted by the inclination of passageways 44, transversely with respect to the axis of bore 32 within duct 14, having a circumferential direction component in the same direction of flow of gas around chamber 30. However, the flow of gas around chamber 30 and such direction component also tends to cause streams 46 to pass helically or in a spiral path, during the flow of the gas from passageways 44 first converging and then diverging frusto-conically in duct 14.

30 Finally, it is to be understood that various alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the spirit or ambit of the invention.

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Claims

1. A pneumatic device, operable as an air mover or air pump, the device having an elongate tubular body defining a through bore having an inlet end and an outlet end, with an annular chamber which extends substantially concentrically around the bore being provided intermediate of the ends of the bore; wherein the chamber is in communication with the bore via a plurality of passages spaced circumferentially around the bore, and the device has an inlet port by which the chamber is connectable to a source of pressurised gas for flow of the gas from the chamber into the bore; each passage having an opening into the bore such that a jet of pressurised gas from each *o opening is directed along the bore towards said outlet end and thereby generates a reduction in pressure in the bore upstream of said openings such that a fluid is able to be drawn into said inlet end and along the bore for discharge with the pressurised gas from the outlet end; the passages S' being inclined both radially inwardly towards and transversely with respect to a longitudinal axis of the bore such that a flow of the pressurised gas is generated in the bore by said jets which, extending axially from said openings towards said outlet end, at first converges substantially frusto-conically to define a throat which is of reducing cross-section down to a minimum cross-section, the flow thereafter diverging outwardly.

2. A device according to claim 1, wherein said passages are inclined inwardly towards said axis at an angle of i',t from 2 to 30 3. A device according to claim 1, wherein said passages are inclined inwardly towards said axis at an angle of from 3 to 150

4. A device according to claim 1, wherein said passages are inclined inwardly towards said axis at an angle of from 3 to 100 A device according to claim 1, wherein said passages are inclined inwardly towards said axis at an angle of from 5 to 100 39 6. A device according to any one of claims 1 to 4 4; 44 II 41 4 4#f 4* IL 495 4950F I Cr I 1 I *4 SIr I I 1$ wherein each said passage is inclinedwith respect to said axis at an inclination angle of up to 200.

7. A device according to claim 6, wherein said inclination angle is at least

8. A device according to claim 6, wherein said inclination angle is from 4 to 150.

9. A device according to claim 6, wherein said inclination angle is from 5 to 150. A device according to any one of claims 1 to 9, wherein said inlet port is substantially tangential with respect to said chamber such that an annular flow of said pressurised gas is generated in said chamber, with said annular flow being in a circumferential direction in said chamber such that flow from the chamber to said passages is in the same direction.

11. A device according to any one of claims 1 to wherein a portion of the tubular body adjacent to said inlet end is belled so as to increase in diameter towards that end upstream with respect to said chamber. 20 12. A device according to claim 11, wherein said belled portion is flared with a radius of curvature in excess of the radius of the bore adjacent to the chamber.

13. A device according to claim 12, wherein the radius of curvature exceeds the radius of the bore adjacent the chamber by a factor of from 1.2 to 1.6.

14. A device according to any one of claims 1 to 13, wherein the tubular body downstream of the chamber is substantially cylindrical. A device according to any one of claims 1 to 13, wherein the tubular body downstream of the chamber is flared so as to increase in diameter away from the chamber.

16. A device according to claim 15, wherein the increase in diameter is substantially uniform.

17. A device according to claim 16, wherein the bore increases in diameter downstream of the chamber by an angle of from 5 to 100 to the axis of the bore.

18. A device according to claim i, substantially as 4950F herein described with reference to the accompanying drawings. DATED: 23 June 1989 PHILLIPS ORMONDE FITZPATRICK Attorneys for: JOHN STANLEY MELBOURNE 39 4950F -9- 4950F -9-