WO1988007895A1

WO1988007895A1 - A cleaning system

Info

Publication number: WO1988007895A1
Application number: PCT/AU1988/000097
Authority: WO
Inventors: Robert James Green; Terence Arthur Bevan
Original assignee: Foamtech Pty. Ltd.
Priority date: 1987-04-06
Filing date: 1988-04-06
Publication date: 1988-10-20

Abstract

A cleaning system for dispensing an aerated cleaning liquid, the cleaning system including a container (1) for a cleaning liquid to be dispensed in aerated form, means (2) for causing pressurisation of the cleaning liquid in use, a liquid supply line (4a) for conveying pressurised cleaning liquid from the container (1), a pressurised air line (3b) for receiving air under pressure, a mixing means (10) for receiving pressurised air from the air line (3b) and also for receiving liquid under pressure from the liquid supply line (4a) and being arranged to cause mixing of pressurised air and pressurised cleaning liquid therein to form an aerated form of the cleaning liquid, a discharge outlet (4c) downstream of the mixing means (10) and where cleaning liquid is in use discharged in an aerated form, and a selectively operable control valve (12) located at or in close proximity to the discharge outlet (4c), the control valve (12) being operable by a user to selectively allow or stop discharge of aerated cleaning liquid from the discharge outlet (4c).

Description

A CLEANING SYSTEM This invention relates to cleaning systems and particularly to systems for the delivery of aerated cleaning liquid (foam) for cleaning large areas such as can be found in abattoirs and the like. The most basic system known in the past for foam cleaning utilizes a supply of cold water to a venturi which is connected to a drum of cleaning liquid. The cleaning liquid is delivered with the assistance of air also fed into the venturi to generate a foam which is expelled through a hose at the cleaning site. The major disadvantage of this basic form is that the water feed is not necessarily constant and it is not possible to meter the chemical concentration arriving at the cleaning site in the form of foam. The system therefore is quite wasteful of expensive cleaning liquid (chemical) and cannot enable the use of hot water or alkaline which is commonly desirable. In an improved form of cleaning system according to the prior art, a drum of cleaning liquid including a foaming agent and alkaline is connected to a pump operated by air to draw the liquid up and through a venturi where it is aerated with a- supply of air into a foam for subsequent delivery through a hose to the cleaning site. Such a system is shown in Fig. 1.

Referring to Fig. 1, it can be seen further that an in line lubricator (oiler) is provided in the air line. An on/off valve ensures a clean flow of air.to the pump. A disadvantage of the prior art as shown in Fig. 1 is that should the delivery hose kink, the cleaning liquid fills the oiler and the pump head which can damage the pump and render the cleaning device inoperable.

In the prior art system just described, it is therefore not possible to have an on/off tap on the hose at the cleaning site, as this is the equivalent of a hose kink, and it is always necessary to return to the on/off valve in the air line near the pump to stop the cleaning device.

A further problem with the prior art system just described is that should the drum of cleaning liquid empty, and as a result the pump empty, the pump races leading to pump damage. It is an object of the present invention to provide a cleaning system which overcomes or alleviates the problems of the prior art as described above.

According to the present invention there is provided a cleaning system for dispensing an aerated cleaning liquid, the cleaning system including: a container for a cleaning liquid to be dispensed in aerated form, means for causing pressurisation of the cleaning liquid in use, a liquid supply line for conveying pressurised cleaning liquid from the container, a pressurised air line for receiving air under pressure, a mixing means for receiving pressurised air from the air line and also for receiving liquid under pressure from the liquid supply line and being arranged to cause mixing of pressurised air and pressurised cleaning liquid therein to form an aerated form of the cleaning liquid, a discharge outlet downstream of the mixing means and where cleaning liquid is in use discharged in an aerated form, and a selectively operable control valve located at or in close proximity to the discharge outlet, the control valve being operable by a user to selectively allow or stop discharge of aerated cleaning liquid from the discharge outlet. Preferably the container for cleaning liquid is a pressure vessel and the means for supplying liquid under pressure includes a pressurised air inlet to the pressure vessel, the pressurised air inlet being supplied in use with pressurised air so as to pressurise cleaning liquid in the vessel and enable supply of pressurised cleaning liquid through the liquid supply line, the pressurised air inlet and the pressurised air line leading to the mixing means being supplied from a common pressurised air source. The pressurised air supplied to the pressure vessel may be at a pressure from 10 to 140 μsi, preferably less than 60 psi (about 410 kpa) and most preferably about 20 psi, the pressurised air line receiving pressurised air at substantially greater pressure than the pressure vessel.

In one embodiment the mixing means is located at or near the discharge outlet, the pressurised air line and the liquid supply line extending over a substantial distance before reaching the mixing means whereby the aeration of the cleaning liquid occurs at or close to the discharge outlet. The mixing means preferably comprises a mixing valve having an inlet connected to the pressurised air line and an inlet connected to the liquid supply line, the mixing valve being selectively operable to enable flow of air and cleaning liquid into a mixing zone provided in the mixing valve, the aerated cleaning liquid created in the mixing zone in use passing through an outlet to the control valve and thence to the discharge outlet. In an alternative embodiment, the mixing means is located relatively close to the container, the system including a foam line extending from the mixing means to the discharge outlet, the foam line conveying in use aerated cleaning liquid from the mixing means to the discharge outlet. The means for causing pressurisation of the cleaning liquid may comprise a pump associated with the container and operative to pump cleaning liquid from the container along the liquid supply line, the pump comprising an air operated pump operative to be driven by compressed air supplied through a pump air supply line, the pump air supply line including an air supply regulator operative to meter the supply of air to the pump so as to maintain the speed of the pump below a predetermined level. In this embodiment the air operated pump and the pressurised air line to the mixing means are preferably supplied from a common pressurised air source, the system including a non-return valve in the air supply line which is operative to prevent flow of pressurised liquid from the mixing means through the pressurised air line thereby reaching the pressurised air source or the air operated pump.

The system preferably further includes a non-return valve located within the pressurised air line and operative to prevent cleaning liquid passing through the air line from the mixing means in the event of loss of pressure in that line.

Preferably the liquid supply line between the container and the mixing means includes a restrictor valve operative to control the maximum flow of cleaning liquid being supplied through the liquid supply line to the mixing means.

Possible and preferred features of the present invention will now be described with particular reference to the accompanying drawings. However it is to be understood that the features illustrated in and described with reference to the drawings are not to be construed as limiting on the scope of the invention. In the drawings: Fig. 1 shows a prior art cleaning system,

Fig. 2 shows a cleaning system according to a preferred embodiment of the invention, Fig. 3 shows a cleaning system according to an alternative preferred embodiment, and

Fig. 4 shows a yet further preferred embodiment of a cleaning system.

5 Referring to Fig. 2, the container or drum 1 contains the chemical liquid comprising foam agent, alkaline and hot water, although hot water is not essential. As the drum is filled with hot water, preferably as close to boiling point as possible, alkaline is added first and then the foaming agent.

10 Connected to the drum 1 is the means for causing pressurisation of the cleaning liquid shown as an air powered pump 2, preferably made from stainless steel and teflon packed. Such pumps are known and sold under the name "Graco" transfer pumps. Leading into the pump 2 is a pressurised air line 3. Liquid supply line 42 conveys

15 pressurised liquid from the tank 1 by action of the pump 2.

The air line 3 has placed therein an in line lubricator 5, an air supply regulator 6 to meter the air to the pump, in line air filter 7 and on/off valve 8. The regulator 6 may be a runaway protector or a regulator of a known type that meters the air going into the pump 2

²⁰ along the pump air supply line 3a to keep the pump stroke even. Whereas the prior art slows the pump down by restricting air, the present use of a runaway protector 6 enables the speed of the pump 2 to remain constant even when there are no chemical liquids. Similarly, the runaway 6 protector enables discharge of liquid to be

²5 stopped which in turn will stop the pump 2, and provides a significant operating advantage as the system can be controlled from the cleaning site.

The liquid supply line 4a has placed therein a restrictor valve 9 to control the maximum flow of cleaning liquid, mixing means 1Q shown

3° as a venturi 10, hose connection 11 and selectively operable on/off tap or valve 12 at or near the discharge end 4c of the hose 4 nearest the intended cleaning site. A branch of the air supply line 3 is tube 3b which connects to the mixing means 10 and includes a second adjustable restrictor valve 14 and non return valve 15 at the ends.

-'-' The non return valve 15 prevents the flow of chemical into the air supply line 3a and the pump 2. The restrictor valve 14 controls the decree of aeration of the chemical liquid. The runaway protector 6 ensures an even supply of air to the pump 2 for even puπp stroke and avoidance of pump head overrunning. The mixing means 10 in Fig. 2 is close to the container 1, and foam line 4b extends to the discharge outlet 4c and carries foam formed in the mixing means 10.

Referring to Fig. 3, the container is shown as a pressure vessel 16 connected to an air supply line 17 via an air inlet 17a fitted with a three way air valve 18. The air valve 18 can be vented to atmosphere via tube 19 to depressurize the vessel 16 when the air supply is switched off.

The pressure vessel 16 is further provided with a quick release drop-in top 20 to enable filling. A non return valve 21 and restrictor valve 22 are also placed in the air supply line to prevent respectively the back flow of chemical from the pressure vessel 16 and also to control the amount of air mixing with the chemical in the liquid line at the mixing means (T-junction) 24 with the foam passing to the foam line 25.

In operation, the pressure in the vessel 16 forces the liquid therein out through the liquid line 23 into the T-junction 24 which mixes with air into a foam which passes to atmosphere through the foam line 25. A number of further valves being a non return valve 25 and restrictor valve 27 in the liquid line 23 operate in the same fashion as the valves 21, 22 in the air line 17b. Finally, on/off or control valves 28 and 29 are provided in the foam line 25 to enable operation of the device in a convenient and functional manner, the control valve 29 being near the discharge outlet 25a.

The benefit from the combination of the features disclosed in the various preferred embodiments is to provide a cleaning device and system which is functional over the prior art and utilizes cleaning liquid in a controlled way so that the amount of cleaning liquid is substantially less than that required using prior art systems whilst achieving the same cleaning effect. In particular a "dry" foam having a closely controlled_ amount of liquid relative to the amount of air enables the foam to cling to sloping or vertical surfaces for example v/hereas prior "wet" foams quickly run off with waste of liquid and ineffective cleaning.

In Fig. 4 the pressure vessel 16 supplies liquid line 23 which can be quite long, e.g. up to 50 metres or more. A similarly long air supply line 17b is provided. The mixing means 10 is located near the discharge outlet 25a so that aeration occurs at or close to the discharge outlet 25a. The mixiny means comprises a mixing valve 30 having an inlet 31 connected via non return valve 21 to the pressurised air line 17b and an inlet 32 connected via non return valve 26 to the liquid supply line. The mixing valve 30 is selectively operable to enable flow of air and cleaning liquid into a mixing zone provided in the mixing valve 30, the aerated cleaning liquid created in the mixing zone in use passing through an outlet 33 to the control valve 29 and thence to the discharge outlet 25a.

In either Figs. 3 and 4, the pressurised air supplied to the pressure vessel 16 through the pressurised air inlet 17a may be at a pressure between 10 and 140 psi, preferably less than 60 psi (about 410 kpa) and most preferably about 20 psi, the pressurised air line 17b receiving pressurised air at substantially greater pressure than the pressure vessel 16. It is to be understood that various alterations, modifications and/or additions may be made to the features of the possible and preferred embodiment(s) of the invention as herein described without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

CLAIMS 1. A cleaning system for dispensing an aerated cleaning liquid, the cleaning system including: a container (1,16) for a cleaning liquid to be dispensed in aerated form, means (2,17) for causing pressurisation of said cleaning liquid in use, a liquid supply line (4a, 3) for conveying pressurised cleaning liquid from the container (1,16), a pressurised air line (3b, 17b) for receiving air under pressure, 0 a mixing means (10,24) for receiving pressurised air from said air line (3b, 17b) and also for receiving liquid under pressure from said liquid supply line (4a, 3) and being arranged to cause mixing of pressurised air and pressurised cleaning liquid therein to form an aerated form of the cleaning liquid, 5 a discharge outlet (4c, 25a) downstream of said mixing means (10,24) and where cleaning liquid is in use discharged in an aerated form, and a selectively operable control valve (12,29) located at or in close proximity to said discharge outlet (4c,25a), said control valve ⁰ (12,29) being operable by a user to selectively allow or stop discharge of aerated cleaning liquid from said discharge outlet

(4c, 25a).

2. A system as claimed in claim 1 characterised in that said container for cleaning liquid is a pressure vessel (16) and said 5 means (17) for supplying liquid under pressure includes a pressurised air inlet (17a) to said pressure vessel (16), said pressurised air inlet (17a) being supplied in use with pressurised air so as to pressurise cleaning liquid in the vessel (16) and enable supply of pressurised cleaning liquid through said liquid supply line (23), ° said pressurised air inlet (17a) and said pressurised air line (17b) leading to said mixing means (24) being supplied from a common pressurised air source.

3. A system as claimed in claim 2 characterised in that said pressurised air supplied to said pressure vessel (16) through said 5 pressurised air inlet (17a) is at a pressure less than 60 psi (about 410 kpa), said pressurised air line (17b) receiving pressurised air at substantially greater pressure than said pressure vessel (16).

4. A system as claimed in any one of claims 1 to 3 characterised in that said mixing means (10) is located at or near the discharge outlet (25a), said pressurised air line (17b) and said liquid supply line (23) extending over a substantial distance before reaching said mixing means (10) whereby the aeration of the cleaning liquid occurs at or close to the discharge outlet (25a).

5. A system as claimed in claim 4 characterised in that said mixing means (10) comprises a mixing valve (30) having an inlet (31) connected to said pressurised air line (17b) and an inlet (32) 0 connected to said liquid supply line (23), said mixing valve (30) being selectively operable to enable flow of air and cleaning liquid into a mixing zone provided in the mixing valve (30), the aerated cleaning liquid created in the mixing zone in use passing through an outlet (33) to said control valve (29) and thence to said discharge 5 outlet (25a).

6. A system as claimed in claim 1 characterised in that said means (2) for causing pressurisation of said cleaning liquid comprises a pump (4) associated with said container (1) and operative to pump cleaning liquid from said container (1) along said liquid supply line 0 (4a), said pump (4) comprising an air operated pump operative to be driven by compressed air supplied through a pump air supply line (3a), the pump air supply line (3a) including an air supply regulator (6) operative to meter the supply of air to the pump (4) so as to maintain the speed of the pump (4) below a predetermined level.

7. A system as claimed in claim 5 characterised in that said air operated pump (4) and said pressurised air line (3b) to said mixing means (10) are supplied from a common pressurised air source (3), said system including a non-return valve (15) in said air supply line (3a) which is operative to prevent flow of pressurised liquid from ° said mixing means (10) through said pressurised air line (3b) thereby reaching said pressurised air source (3) or said air operated pump (4).

8. A system as claimed in any one of claims 1 to 6 and further including a non-return valve (15,21) located within said pressurised 5 a.ir line (3b, 17b) and operative to prevent cleaning liquid passing through said air line (3b, 17b) from said mixing means (10,24) in the event of loss of pressure in that line (3b, 17b).

9. A system as claimed in any one of the preceding claims characterised in that the liquid supply line (4a,23) between the container (1,16) and the mixing means (10,24) includes a restrictor valve (9,27) operative to control the maximum flow of cleaning liquid being supplied through the liquid supply line (4a, 23) to the mixing means (10,24).

10. A system as claimed in any one of claims 1 to 3 characterised in that said mixing means (10,24) is located relatively close to said container (1,16), the system including a foam line (4b,25) extending from the mixing means (10,24) to the discharge outlet (4c, 25a), the foam line (4b, 25) conveying in use aerated cleaning liquid from the mixing means (10,24) to the discharge outlet (4c, 25a).