AU596169B2

AU596169B2 - Method of and means for preventing contamination in liquids flowing from mains fo a consumer device

Info

Publication number: AU596169B2
Application number: AU72037/87A
Authority: AU
Inventors: Wlodzimierz Rast
Original assignee: Rast W Pty Ltd
Current assignee: CONFLOW INDUSTRIES PTY Ltd
Priority date: 1986-03-20
Filing date: 1987-03-20
Publication date: 1990-04-26
Anticipated expiration: 2007-03-20
Also published as: EP0261180B1; WO1987005973A1; DE3773098D1; EP0261180A1; AU7203787A; EP0261180A4; ATE67561T1; JPS63503237A

Abstract

A method of and means for anti-contamination flow control in liquids in a system using a motor unit (1) adapted to be driven by a pressure liquid having its drive coupled to drive a pump unit (6) adapted to pump liquid under pressure to a consumer device (9), in which the liquid is discharged from the motor unit (1) through an air gap (4), and collected from the air gap (4) by the pump unit (6) whereby to continue flow of pressure liquid beyond the air gap (4) to the consumer device (9).

Description

i AU-AI-72037/87 PCT WORLD INTELLECTUAL BOPERTY ORGANIZATION SPCT51 W rna I Bureau INTERNATIONAL AL TI PU1IS ER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 4 t 11 International Publication Number: WO 87/ 05973 F04B 9/10, 23/02, 17/00 F04D 13/04, F15B 3/00 Al (43) International Publication Date: 8 October 1987 (08.10.87) (21) International Application Number: PCT/AU87/00078 (22) International Filing Date: (31) Priority Application Numbers: (32) Priority Dates: 20 March 1987 (20.03.87) PH 5171 PH 5619 24 March 1986 (24.03.86) 24 April 1986 (24.04.86) (74) Agent: COLLISON CO.; 117 King William Street, Adelaide, S.A. 5000 (AU).

(81) Designated States: AT (European patent), AU, BE (European patent), CH (European patent), uE (European patent), FR (European patent), GB (European patent), IT (European patent), JP, LU (European patent), NL (European patent), SE (European patent),

US.

Published With international search report. r (33) Priority Country: AU (71) Applicant (for all designated States except US): W.

RAST PTY. LTD. [AU/AU1; 56 Deeds Road, North Plympton, S.A. 5038 (AU).

(72) Inventor; and Inventor/Applicant (for US only) RAST, Wlodzimierz [AU/AU]; 87 Mount Osmond Road, Mount Osmond, S.A. 5064 (AU).

(54) Title: ANTI-CONTAMINATION FLOW CONTROL IN LIQUIDS (57) Abstract A method of and means for anti-con- PRESSURE tamination flow control in liquids in a system using a motor unit adapted to be driven by a pressure liquid having its drive coupled to drive a pump unit adapted to pump liquid Dlsc under pressure to a consumer device in 3 which the liquid is discharged from the motor unit through an air gap and collected from the air gap by the pump unit 4 whereby to continue flow of pressure liquid beyond the air gap to the consumer device IECEIVING

MEANS

L I I 1 f\ :i 1 1 I I I- 00 O(8 9 oo 00 0 00 0 0 O 0 0 001 ANTI-CONTAMINATION FLOW CONTROL IN LIQUIDS BACKGROUND OF THE INVENTION This invention relates to a method of and means for preventing contamination in liquids flowing from a mains to a consumer device.

As a prior art reference, the specification of United States Patent No.

4297086 of Peter T. McGowan, assigned to The Garrett Corporation, is cited, which uses a first pump unit which acts as a motor unit is driven by a first pressure fluid, is coupled to drive a second pump unit which acts as a slave unit, which second pump unit pressurizes a second fluid system.

In that system, as the first pump unit of a first fluid system, the second pump unit is mechanically driven by the first pump unit and serves as a means of pressurizing the fluid of the second system.

20 The cited United States Patent refers to transferring hydraulic power from one system to another.

Where only a single system is used to drive a consumer device, where pressure liquids flowing from a supply line require to terminate in a 25 consumer device such as washing machine or the like where pressure fluid is required, a serious problem exists, there being danger that the liquid can be contaminated if liquid flow back into the supply line occurs. This readily happens when back-syphoning occurs, such as when the pressure in the supply main ceases or is reduced.

SUMMARY OF THE INVENTION It is the object according to my invention to prevent back-flow in such a hydraulic system.

0 00 o 00 0 0'0 0 0000 Q 0 0 09 1 0 o a 0 0 0Q' 0 00 0 0 According to this invention the problem is solved by having an air gap in the pressure line between the source of supply and the consumer device, the device of the invention being so arranged that no external pressure is required on the receiver side of the device to which the supply is taken, but the pressure is maintained on the consumer side by means on the supply 0 2 side which actuate a pump to maintain the pressure at about the same level as the supply line.

This is achieved according to the invention by having motor units at the terminal end of the pressure line which are driven by liquid flow, the liquid being discharged from these motor units by free fall into a funnel or receiving means to be pumped from this to the consumer line by pump units in the consumer line. The motor units and the pump units are coupled to be driven simultaneously and both are arranged to have as near as possible the same volumetric flow.

The motor units are of a positive type so that they act as a valve in the line when the units are inoperative, and if the pump units are maintained o° stationary no flow from the pressure line takes place from the motor units to 0o 15 the reservoir or funnel. When however the consumer device is actuated the o 0 0o pump units are free to operate and allow the motor units to be driven by the pressure liquid, to discharge the liquid into the reservoir through the air gap which is simultaneously taken up by the pump units under drive of the motor units to discharge to the consumer device. If the consumer device flow is cut off the pump units stop and, as the motor units are coupled to it, they also stop and flow of the liquid from the mains to the motor unite and from the delivery unit to the consumer device stops.

o Po The main object of the present invention thus is to achieve a highly effective method of operation of continuous action of such a device, a further object being a form of construction which is both simple and effective and which if desired can also act as a meter to meter the fluid being used, the latter of o course being an optional feature.

Poo.

00 0 30 The method according to this invention comprises causing flow of pressure 0 0 liquid through motor units adapted to be driven by a pressure fluid having their drive coupled to pump units adapted to pump liquid under pressure to a consumer device, discharging the liquid from the motor units through an air gap, and receiving the liquid discharged from the air gap by the pump units whereby to continue flow of the pressure liquid beyond the air gap to the consumer device.

1116 3 The apparatus comprises motor units to receive a pressure fluid and be driven thereby, means to discharge the fluid from the motor units to a vessel through an air gap, means to couple the motor units to drive the pump units, the pump un;rs drawing liquid from the vessel and pressurizing it into a flow line by reason of the drive of the pump units from the motor units, the initiation of each coupled motor and pump unit being controlled 5y the other coupled motor and pump unit.

The motor and pump units can take various forms but have similar capacities so that pressure liquid flowing through the gap flows on beyond the gap at the same relative pressure by means of the arrangement. When flow from the pump units is stopped, the pump units and the motor units both stop because they are coupled together drive-wise, but immediately the o consumer device draws pressure liquid from the pump units the motor units o 15 are caused to supply the liquid through the airgap in the same proportion as e o the liquid is used by the consumer device.

o According to a preferred form of the present invention two pairs of cylinders are formed in a housing, the one pair of cylinders forming the motor units, which cylinders may be of unequal diameter, in each of which cylinders is a piston coupled by a connecting rod to a piston in the pump units so that a first piston in the motor units drives a first piston in the pump units for 0*4 synchronized operation, while a secord piston in the motor units drives a o0,,O second piston in the pump units.

aOnq Each of these pistons of the motor units are coupled by means of a connecting rod to valve means which control the flow of liquid into the second piston of the motor unit but the out-flow of the motor unit is taken via 0 an air gap to the input of the pump units so that, as a motor unit delivers 30 liquid as it is allowed to be driven as a motor by the pressure liquid from the supply line, it simultaneously activates a piston of the pump unit to receive the liquid from the motor unit and pressurizes it and passes it on to the consumer device. recause both units are coupled together, that is the first and second pistons of the motor unit are coupled to the respective first and second pistons of the pump units, displacement occurring of the pistons in the motor units are matched by displacement occurring of the pistons in the pump units so that while there is an air gap between the two units, the liquid flows from the supply line through each motor unit, then through an air gap, i.,.sZ

IN;

i S4 and is then available to the corresponding pump unit which mal tains the pressure in the on-flowing liquid because of the drive coupling of the units.

The method thus comprises; driving first and second reciprocating motor units by a pressure liquid and receiving in receiver means through an air gap the liquid discharged by the motor units; passing the liquid from receiver means to first and second pump units adapted to collectively pump liquid under pressure to a consumer device; driving the first pump unit by the first motor unit, driving the second pump unit by said second motor unit; activating the second motor unit from said first motor unit when said first motor unit nears the end of its stroke, and 15 activating the first motor unit from said second motor unit when said Ssecond motor unit nears the end of its stroke, whereby to alternately activate the first and the second motor units and thereby continuing flow of pressure o liquid beyond said air gap to the consumer device from the pump units.

o0 0 o ooo4 The apparatus comprises; first and second motor units each adapted to be driven by a pressure liquid; receiver means to receive through an air gap the liquid discharged by the motor units; first and second pump units adapted to receive liquid from the receiver means and pump liquid under pressure to a consumer device; drive means coupling the first motor unit to the first pump unit; drive means coupling the second motor unit to the second pump unit; oa*' the motor units comprising a pair of pistons housed in at least one 30 cylinder, each piston being adapted to be driven alternately through valve means by pressure liquid from a pressure line to form the motor unit to deliver liquid to the receiver means, a pair of pistons housed in at least one cylinder adapted to act through valve means as the pump units to deliver liquid to the consumer device; and means on the drive means positioned to engage and activate the valve means near the end of each stroke of the coupled pistons to actuate the valve means of the other coupled pistons.

In order however, that the nature of the invention will be fully appreciated, embodiments thereof will now be described with reference to the accompanying drawings which are by way of example only, as the primary and secondary pump units can take various form.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, Fig 1 is a flow diagram showing the motor units and the pump units with the pump units driven by the motor units through drive couplers, showing the air gap and vessel which forms the anti-contamination device in that it prevents the back flow of liquid from the pump units to the motor units, o o,o Fig 2 is a somewhat schematic sectional side elevation of a typical assembly comprising both motor units and pump units with each divided into two components, using pairs of pistons and cylinders with the pistons of o, 0 each pair actuated successively, Fig 3 is a similar view to Fig 2 but showing in modifipd form using two pistons and a single cylinder for the motor units and similarly for the pump units, so that the cylinders of each pair are co-extensive and the pistons therein operate in a common chamber, O Oo 0 Figs 4 and 5 are isometric views of a vertical and horizontal arrangement respectively of the units shown in Fig 3.

v o 0o DETAILED DESCRIPTION a e Referring first to Fig 1, which demonstrates the general principle, pressure liquid is fed to the motor units 1 by a pressure line 2 and drives the motor units, the liquid leaving the motor units 1 through the discharge line 3 under low pressure from whence it flows through the air gap 4 to receiving means 5 such as a vessel when the motor units 1 are driven by the pressure liquid.

The pump units 6 have the drive connected by drive couplers 7 so that the motor and pump units 1 and 6 are driven synchronously. The pressure M 6 liquid outlet from the pump units 6 is taken by the pressure line 8 to the consumer device 9.

In operation, when the consumer device 9 accepts pressure liquid, the pump units 6 are free to operate and this allows the motor units to be driven by the pressure liquid connected to the motor units 1.

As the motor and pump units 1 and 6 are coupled, the pressure in the outlet line 8 for the liquid is similar to the pressure in the inlet line 2.

There is however no direct fluid connection between the inflow pressure liquid line 2 and the outflow pressure liquid line 8 because of the interposed air gap 4.

*a o 0 o 15 Referring now to Fig 2, the first and second cylinders 1C and 11 of the motor O units 1 communicate with a valve chest 12 which has a series of ports in it "4 connected to the IN pressure line 2 from the pressure supply and the discharge line 3 from the unit to the air gap 4. These ports are controlled by 0o valves 13 and 14 shown as slide valves, one actuated by a first piston 15 of the motor unit 1 and the other by a second piston 16 of the motor units 1 in such a way that when the first piston 15 of the motor units 1 is displaced by fluid, the valve 13 is moved when the piston reaches near the end of the stroke of that first piston 15 to change the flow through the porting of the valve chest 14, the pressure liquid driving the first piston 15 forward to near the end of the stroke whereupon the slide valve 13 coupled to it moves to \o change the porting to apply the pressure to the second piston 16 of the oo,, motor units 1 to drive that piston 16 to the opposite end of its stroke. As the o second piston 16 nears the opposite end of its stroke the valve 14, o connected to it in the chest 12 is actuated 't again establish the first 30 described state and the first piston 15 is driven in the opposite direction until it reaches near the end of its stroke whereupon the valve 13 coupled to it is again repositioned to actuate the second piston 16 of the motor units.

The arrangement of the pump units 6 is similar to that of the motor units 1 and has a liquid inlet 17 and is arranged so that alternately the two pistons 18 and 19 of the pump units supply the liquid pumping action. The first and second pistons 18 and 19 of the pump units 6 act in cylinders 29 and I Y1 7 The sequence of the pistons 18 and 19 is so arranged that when the first piston 18 is on a delivery stroke the other piston 19 of the unit is stationary but as the first piston 18 reaches the end portion of its delivery stroke the valve 20 in the valve chest 21 is changed to drive the second piston 19 on its stroke, the first piston 18 of the unit having reached the end of its stroke remaining there and cutting off flow until the second piston 19 reaches the end portion of its stroke whereupon the valve 22 in the valve chest 21 is changed and he first piston 18 is actuated on its next delivery stroke.

The first piston 15 of the motor unit 1 and the first piston 18 of the pump unit 6 are connected to move in unison by a drive coupler 7, this being in the nature of a piston rod 23, the second piston 16 of the motor unit 8 and the second piston 19 of the pump unit are similarly connected to move in unison

C'.

0 by a piston rod 24.

0 S.J The valves 20 and 22 of the valve chest 21 are connected respectively to the piston rods 23 and 24, as are the valves 13 and 14.

co, U vo The stems 25 of each of the valves 13,14, 20 and 22 are connected to be actuated by stops 27 in the piston rods 23 and 24 but have interposed springs 28.

o The first cylinder is designated 29 and the second cylinder 30 and house the pistons 18 and 19 respectively.

o°o If desired one of the pistons 15 or 16 of the motor unit 1 may be the main driving piston of the motor unit and can be of a substantial diameter, the second piston being of a smaller diameter as its function is essentially to oo take over the pumping action as the first piston nears the end of its stroke oo: 30 and continues the pumping action while the first piston rests until the second piston reaches near the end of its stroke and the valve is changed over whereupon the first piston is driven in the opposite direction, this arrangement ensuring a continuous flow of liquid and doing away with problems such as water hammer which is one of the basic problems with the mechanisms of this type.

Referring to the modified form shown in Fig 3, in which similar references are used for corresponding parts, the motor unit cylinders 10 and 11 and the C 5'1r R4LEr o./ 8 pump unit cylinders are coaxial and the cylinders 10 and 11 form a common chamber as do the cylinders 29 and 30. The pistons 15 and 16 of the motor unit 1 and the pistons 29 and 30 of the pump unit 6 dividing the cylinders into their two active areas.

The action however is still similar to the form first described but it will be noted .hat as the piston rods 23 and 24 are coaxial, the rod 24 is hollow and has a cut-away 33 to give access to the stops 27 on the piston rod 23.

The piston rod 23 actuates the valves 13 and 20 of the motor and pump units 1 and 6 respectively through a rocker arm 34 which has an intermediate pivot 35 connecting it to a frame not shown, which also carries the cylinders 10, 11, 29, and 30, tihe rocker arm being actuated by the stops oo 27 on the piston rod 23.

The rocker arm 36 is similarly carried by a pivot 37 to engage the valve stem of the valves 14 and 22 to activate these valves from the piston rod 24.

So, The operation of the motor units 1 is as follows:- With the valves 13 and 14, in the position shown in Fig 3, pressure liquid is caused to flow in into the port A and the liquid moves piston 15 down, expelling liquid through the port B and valve 13 into air gap 4 outlet.

C C a At the end of the stroke of the piston 15, the valve 14 is moved to cover the .0 port C and uncover the port B. Mains pressure is maintained through the oo: port A on the piston 15. Mains liquid then flows through the port B and moves the piston 16 down, expelling liquid through the port C to the valve C13 and then to the air gap 4 outlet. At the end of the stroke of the piston 16 30 the va!ve 14 is moved to cover the port A, thus allowing pressure liquid to flow through the port B and move the piston 15 upwards, expelling liquid through the port A and and valve 14 to the air gap 4 outlet. At the end of the stroke of the piston 15, the valve 13 is moved to cover the port B and uncover the port C, allowing pressure liquid to flow through the port C, moving the piston 15 upwards and expelling liquid through the port B to the valve 13 and air gap 4 outlet. At completion of the upstroke of the piston 16, the valve 14, is moved to uncover the port A, completing the cycle of the unit.

9 The operation of the pump units 6 is as follows:- As the piston 18 is moved down by the piston 15, liquid is expelled through the port F and valve 22 to the consumer outlet 8. As this piston 18 moves down, liq, d is drawn in from the receiving means 5 via the port E and valve The valve 20 is moved upwards. The piston 19 moves down expelling liquid through port E to the outlet 8. Liquid is drawn in through the valve and port D to the top side of the piston 19. The valve 22 is moved upwards.

As the piston 18 moves upwards, liquid is expelled through the port E and valve 20 to the consumer outlet 8. Liquid is drawn in through valve 22 and port F to the underside of piston 19. The valve 20 is moved down. The piston 19 is moved upwards, expelling liquid through the port D and valve o 20 to the consumer outlet 8. the underside of the piston 19 draws liquid in o° 15 through the valve 20 and port E. The valve 22 is moved downwards. This completes the cycle of the pump of the pump units 6 at the same time as that of the motor of the motor unit 1.

o0 °o o °O It will be realized that whatever water or other liquid passes through the motor units 1 will be taken up through the air gap 4 by the pump units, and the liquid will be pumped by the pump units 6 to the consumer device 9 at a pressure substantially that of the supply means pressure because both units 0066 a oo are connected to operate synchronously, so that while the stream of liquid is o interrupted by the air gap 4, the pressure liquid on the IN side of the motor units 1 drives that pump units to actuate the pump units 6 to maintain the o0066 csame substantial pressure on the consumer side of the line.

In Fig 2 a mechanical meter 40 is shown to record volume of water or other o o liquid used.

The operation of the device which forms this invention as described and illustrated with reference to the foregoing embodiments will be readily appreciated if it is realized that the motor units 1 will have the pressure from the supply means on them at all times but can only operate when the pump units are free to move, because the driven means are coupled on an equalcapacity basis to the driven means of the pump units 6 so that if there is no outflow from the pump units 6 to the consumer device 9 that unit is locked and holds the driven means of the motor units similarly locked. While the drive for the whole unit comes from the pressure exerted on the motor unit 1, the control of flow is by the consumer device 9 which controls the output of the secondary pump units 6.

By using positive displacement means for the pump unit and the delivery unit it will be realized that at the consumer end the effect is as though there is a direct pressure line connection between the supply line and the consumer device but because of the air gap no back flow can take place through the unit so that there is no risk of contamination as the consumer device cannot feed back liquid to the mains as such flow could not take place across the air gap.

o p o Q 0 04 o o, 0 0 .0 4 0 Oq 0 0 0 0 4

Claims

1. A method of anti-contamination flow control in liquids, comprising: driving first and second reciprocating motor units by a pressure liquid and receiving in receiver means through an air gap the liquid discharged by the motor units; passing the liquid from receiver means to first and second pump units adapted to collectively pump liquid under pressure to a consumer device; driving the first pump unit by the first motor unit, driving the second pump unit by the second motor unit; activating the second motor unit from the first motor unit when the first motor unit nears the end of its stroke, and activating the first motor unit from the second motor unit when the second motor unit nears the end of its stroke, whereby to alternately activate said first and said second motor units and thereby continuing flow of pressure liquid beyond said air gap to the consumer device from the pump units.

2. The method of Claim 1 wherein: the motor units comprise a pair of pistons in at least one cylinder, and valve means; the pump units also comprise a pair of pistons in at least one cylinder and valve means; the method further including: feeding pressure liquid to the valve means of the motor units from a pressure line and allowing the liquid to discharge from the motor units through the air gap to the receiver means, and receiving the liquid from the receiver means and pressurizing the liquid in the pump units to supply pressurized liquid at the consumer device, whereby .1 the flow of liquid through the motor units is synchronized with the flow of liquid through pump units by drive couplings between said motor units and the pump units.

3. Apparatus for anti-contamination flow control in liquids comprising: first and second motor units each adapted to be driven by a pressure liquid; receiver means to receive through an air gap the liquid discharged by the motor units; a o t 0 00 X 0 0 T 4 12 first and second pump units adapted to receive liquid from the receiver means and pump liquid under pressure to a consumer device; drive means coupling the first motor unit to the first pump unit; drive means coupling the second motor unit to the second pump unit; the motor units comprising a pair of pistons housed in at least one cylinder, each piston being adapted to be driven alternately through valve means by pressure liquid from a pressure line to form the motor unit to deliver liquid to the receiver means, and a pair of piston housed in at least one cylinder adapted to act through v ve means as the pump units to deliver liquid to the consumer device; and means on each of the drive means positioned to engage and activate valve means near the end of each stroke of the coupled pistons to actuate the valve means of the other coupled pistons.

4. Apparatus for anti-contamination flow control in liquids comprising: a first piston and a second piston in first and second cylinders to form a pair of motor units; a first piston and a second piston in first and second cylinders to form a pair of pump units; a first piston rod coupling the first piston of the motor unit to the first piston of the pump unit; a second piston rod coupling the second piston of the motor unit to the second piston of the pump unit; means coupling the piston rods to valves to cause the pistons of the pairs to be driven alternately; said means including stops on the piston rods positioned to engage means which actuate the valves near the end of the stroke of the pistons, whereby, as the coupled first pistons near the end of their stroke, the valves are actuated, to cause the Scoupled second pistons to be actuated and when the coupled second pistons near the end of their stroke the valves are activated to cause the coupled first pistons to be actuated.

5. Apparatus according to Claim 4 wherein: the first cylinders of the motor unit and the pump unit are coaxial; and the cylinders of the second motor unit and the pump unit are coaxial. -o 00 t C P0 0 l P0 Z C I1 0000 0 0 4T 0~ O ir 0 0 90 0t 0. 9o. <N0BA410 00 0 0 t 0 0 I I 13

6. Apparatus according to Claim 4 wherein: all the cylinders are coaxial, the cylinders of the motor unit being co- extensive and the cylinders of the pump unit being co-extensive whereby the pistons of the motor unit are positioned in a common chamber and the pistons of the pump unit are also positioned in a common chamber. Dated this 18th day of October 1989 Do c o o 04 '6 0 V~ V V DOP 049 DO O aq W RAST PTY LTD By his Patent Attorneys COLLISON CO, &J 4034 DOd 0 0 O -i