AU5423401A - Method of cleaning and cleaning systems - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT o oooo o oooo *oooo* *o o oeoo *0 oooo oooo Invention Title: METHOD OF CLEANING

SYSTEMS

AND CLEANING Applicant: UNSDALE PTY LTD The following statement is a full description of this invention, including the best method of performing it known to me: 1 Document4 2 Method of Cleaning and Cleaning Systems The present invention relates to a method of cleaning and to a cleaning system for use therein.

Background Equipment used in the food processing industry must be kept clean and free of food build up. Pipes and vessels used in handling food are regularly cleaned so that there is a significant loss of production time occupied in cleaning and maintenance.

This is especially a problem with apparatus used in the food industry to concentrate liquids such as milk, fruit juice, sugar solutions and the like. For example falling film evaporators are used in concentrating liquids and contain a number of evaporator units, called effects, each of which include a housing and 0a multiplicity of tubes known as callandria, through which liquid to be evaporated is caused to flow downward as a film on the inner surfaces. The outer surfaces of the tube are heated by steam or other heating mechanism.

20 Food residue tend to build up on the vessels and tubing and pipes involved in transfer of liquids. In the case of milk the residues form a stubborn build up called "milk stone" which is particularly difficult to remove.

f International patent application PCT/AU94/00457 describes one type of multiple ee 0. 25 effect evaporator and a distributor plate which allows more efficient cleaning.

Another example of equipment requiring regular cleaning and maintenance is milking equipment used in commercial dairies.

Manual and automatic methods of cleaning food processing equipment are used however even in a plant with advanced cleaning equipment, a significant amount of manual cleaning is required. Equipment is generally cleaned every 24 hours depending on the potential for build up of residue on surfaces. There w:qeanniespieS\647289.dc 3 is a need for improvements in the efficiency of cleaning food processing equipment such as evaporators, dairy equipment and the like.

Summary of the Invention In accordance with a first aspect of the invention we provide a method of cleaning industrial food processing equipment or components thereof comprising applying a cleaning liquid to the food processing equipment or components thereof wherein the cleaning liquid is fed to the equipment or components through a transfer line provided with a means for injecting gas under pressure to the transfer line and wherein one or more pulses of gas are injected into the transfer line under pressure thereby accelerating the cleaning liquid, to increase the force with which the cleaning liquid is applied to processing equipment or components thereof.

:The invention further provides a system for cleaning food processing equipment ,:i or components thereof the system comprising a transfer line for applying cleaning liquid to the food processing equipment or components thereof and means for injecting one or more pulses of gas under pressure into the transfer ooooo line to accelerate the cleaning liquid applied to the food processing equipment or components thereof.

Preferably a non-return valve is provided in the transfer line upstream of the injection of the gas into the liquid stream. The non-return valve such as a S 25 butterfly valve aids in producing acceleration of the liquid downstream of the injection point.

The method may use one or more pulses of gas to accelerate the cleaning liquid. In some instance a single intense pulse of cleaning liquid may be used to achieve the desired effect. For example in cleaning the milking apparatus used in small dairies a single pulse may be effective. In dairies a particular problem exists with the cleaning of the claws which receive milk from milking cups. In commercial equipment a number of claws are provided with pipe work which collect the milk in a manifold before it is stored. The build up of milk w:jeanniespecies\47289.doc 4 residue can cause a serious contamination problem but the maintenance of claws is normally time consuming. We have found that this problem can be overcome by pumping cleaning liquid into the pipe which collects milk from the claws and injecting gas into the pipe to accelerate the cleaning liquid in a direction opposite that used in milk collection and into the claws. A valve may be provided upstream of an injection site to force the cleaning liquid toward the claws. The use of a plurality of pulses is preferred.

In cleaning apparatus such as multiple effect evaporators it is preferred to use a multiplicity of high frequency pulses.

In a particularly preferred embodiment the system of the invention includes a liquid accelerating portion including at least two sections in parallel wherein at 0 o least one of the at least two sections in parallel includes means for injection a 15 gas under pressure into and valve means for inhibiting backflow in the said sections in parallel. The accelerator portion may include at least three conduits :3 in parallel including at least two conduits each provided with gas injection *means and a non-return valve upstream of the gas injection means and at least one further conduit for use in transfer of a food product during a food ooeoo 20 processing operation of the food processing apparatus or component thereof.

0. The apparatus of the invention preferably includes means for adding a cleaning agent. Preferably the cleaning agent is added to the gas prior to its injection into the cleaning liquid. We have found that the injection of compressed gas 25 containing a mist or vapour of cleaning agent significantly improves cleaning action by providing one or more bursts of cleaning agent to coat the surfaces to be cleaned.

Alternatively the apparatus of the invention may further be provided with means for feeding cleaning chemicals into the cleaning liquid by a venturi provided in one or more of the at least two sections in parallel. The venturi is more preferably located downstream of the injection of gas under pressure.

w:e anniespecies%647289.doc The cleaning liquid is preferably pumped through the cleaning section and the injection of the gas under pressure into the cleaning liquid will typically increase the liquid velocity by 100% and preferably at least 200%.

The gas is preferably compressed air although other gases may be used if desired. For example air sensitive materials may be cleaned by accelerating cleaning liquid using an inert gas such as nitrogen.

The gas is preferably fed into the liquid as high frequency pulses. More preferable the frequency of pulses is in the range of from 5 to 20 per minute depending on the soil type, pipe configuration, pump characteristics, volume and pressure of air.

Air to liquid ratio is a function of pumping rate, pipe configuration, air pressures the volume of pipe work and equipment being cleaned and the mode of operation required. Preferably it is in the range of from 4:1 to 1:10 for air at psi and inch air inlet.

Preferred embodiments of the invention will now be described with reference to the attached drawings.

i' In the drawings: Figure 1 is a schematic view of one embodiment of the invention.

Figure 2 is a schematic view of an alternative embodiment including means for transferring chemicals.

Figure 3 is a schematic view of commercial dairy milking equipment provided with the cleaning system of the invention. It is particularly useful in accelerating the cleaning liquid to clean the claws and milking cups.

Figure 4 is another embodiment of the cleaning system of the invention which is particularly suited to cleaning multiple effect evaporator holding tubes.

w: eannievspecies%47289.doc 6 Figure 5(a) is an embodiment of the apparatus of the invention for cleaning the claws of milking equipment and which may be used in place of the cleaning system of the invention (36) in Figure 3.

Figure 5(b) shows the turbulent flow of cleaning liquid produced in the claws using the system of Figure Figure 6 shows a modification of the cleaning system of Figure 1 for allowing cleaning agent to be injected with compressed gas.

Figure 7 is a modification of the cleaning system of Figure 6 in which air bleeds are provided in two of the conduits in parallel.

Referring to Figure 1 there is shown a cleaning system in accordance with the invention for use upstream of the equipment to be cleaned such as :i evaporators, heat exchangers and associated pipework.

The cleaning system includes an upstream portion for receiving liquid for use in ooo o cleaning a downstream portion for feeding accelerated pulses of cleaning liquid to the apparatus to be cleaned and a liquid accelerator section for accelerating the cleaning liquid to provide pulses of cleaning liquid. The liquid accelerator section includes at least two conduits (5a, 5b, 5c) connected in parallel to said upstream portion and said downstream portion at least one (5a, 5b) of said parallel conduits including injection means (6a, 6b) for compressed gas.

The system also includes one or more valves (7a, 7b) upstream of the means for injecting compressed gas and valve means (8a, 8b, 8c) for inhibiting backflows of liquid in the others of said conduits connected in parallel (5a, The system is generally fed by a pump in said upstream portion A reducing device (8d) is preferably provide downstream of the accelerator section to allow regulation of flow to provide optimum performance of the system. The reducing device may for example be a butterfly valve with the w:Jeanniespeces\847289.doc 7 appropriate sized orifice. The system of the invention may include a number of accelerator sections in series if desired.

A method of operating the system of the invention will now be described with reference to Figure 1.

Under operation conditions a liquid food product such as milk, fruit juice or sugar solutions passes through each of conduits (5a, 5b, 5c) in parallel in the liquid accelerator section B During the cleaning cycle liquid food product is purged from the system and cleaning liquid is introduced to the accelerator section via upstream portion into each of the conduits (5a, 5b, 5c) connected in parallel to the downstream portion Air is injected under pressure at injection means (6a) and non-return valve (7a) up stream thereof is closed. The liquid in the conduit (5a) in which air is injected is accelerated into downstream oooo position at a velocity dependent on the pressure and volume of air entering at gas injection means The pressure produced by air injection will cause ~opening of valve (8a) in the conduit (5a) in which air is injected and closure of valves (8b, 8c) inhibiting backflow if liquid in others of said conduits in parallel This procedure may be repeated in other conduits (5b) containing injection means (6b) cleaning which other conduits (6a, 6c) are filled with liquid. The frequency and volume of air injected at gas injection means (6a, 6b) may be set to provide an increase in velocity of over 100% and/or to produce an increase in 25 cleaning efficiency per unit volume of liquid by over 100%. The frequency and volume of air injected at injection means (6a, 6b) may also allow the pump to operate within its operating range.

When the system is not required to be very high hygienic control each of the conduits in parallel (5a, 5b, 5c) may include gas injection means (6a, 6b).

However when used to clean hygienic equipment it is preferred to isolate conduits (5a, 5b) containing injection means (6a, 6b) during operation with food products by closure of valves (7a, 7b, 8a, 8b) and to provide a discrete product conduit w: eanniespecies\647289,doc 8 A venturi may optionally be fitted in conduits (5a, 5b) provided with gas injection means (6a, 6b) and the venturi may be provided with means for transferring cleaning chemicals into the gas stream of said gas injection means (6a, 6b) or an accelerated liquid downstream of said air injection means (6a, 6b).

The plugs of liquid in the downstream section 3 vary in compaction from mixture of gas and liquid to primarily liquid. We have found that the air liquid mixture mixing at high velocity has a strong scouring effect and is highly effective in removal of residues.

Referring to Figure 2 there is shown a system of the invention 10 including a product transfer line (11) for feeding liquid such as milk to be processed for example by evaporation and a chemical dosing conduit (12) provided with a venturi (13) with chemical dosing point (14) provided with cleaning chemical reservoirs (15) which may include means (16) for mixing chemical component of the cleaning liquid including water, acid, alkali or other cleaning materials. At first non-return valve (17) is provided in the chemical dosing unit downstream of the venturi. In accordance with one embodiment of the invention a compressed i gas injection means (18) is provided in product transfer line (11) and a second non-return valve (19) is provided upstream of the compressed gas injection means (18) to inhibit backflow of liquid and produce acceleration of liquid downstream of the compressed gas injection means (18) in said product transfer line (11).

The compressed gas injection means (18) may be provided with a compressed air storage tank (20) supplied by compressor (21) and a valve (23) operable to inject air into product transfer line (11).

.Preferably the gas injection means valve (19) in the product transfer line (11) and chemical closing point (14) are under control of a PLC (23) to provide automatic regulation of these features in a predetermined sequence.

w:4eannie\speies\647289.doc 9 The system of the invention shown in Figure 2 may be operated in a multi-step process as follows: An upstream pump was started up and upstream valve (19) was in the open position. The lines (11, 12) were filled with water and upstream valve (19) was shut and air injected at gas injection means Plug of water pushed by the expanding air is accelerated up the pipeline The valve (17) in chemical closing conduit (12) and closed to produce a pulse of compressed air to accelerate a plug of liquid upstream. The injection period is programmed into the PLC (23) and depends on the configuration of the pipeline and/or vessel being cleaned.

The valve (22) of the gas injection means is opened for brief period (generally less than 10 seconds). At this time the cleaning solution injected into the water oo 15 in chemical closing conduit (12) when their air pressure decrease in M reaches a pressure that allows a sufficient flow to draw the cleaning chemicals into the liquid at the venturi (13).

There are a multitude of scenarios and combinations of plug flow composition.

20 For instance to get the best cleaning effect when cleaning a vessel fitted with spray balls, the following functional description could be applied.

Step 1. Purge product line using air, of contents into product storage tanks.

Hence less product loss due to dilution.

Step 2. Pulsating rinse which would use less than half the water a convention system would use.

Step 3. Low turbulence and concentrated alkali wash so as to allow absorption of the alkali. This allows the use of specific chemicals in small volume to break the bond between the soil and surface of the apparatus.

Step 4. High mechanical energy pulsating wash to remove the softened soil.

This can be alternated rapidly, with varying concentration of alkali to remove the w:eanniespecies%647289doc multi strata of soil layers. For instance a straight water pulse can be delivered to remove alkali to be followed by acid to remove calcium salts which impede the penetration of the alkali into the soil.

Referring to Figure 3 there is shown a schematic view of a commercial dairy milking station (30) equipped with a cleaning system (31) in accordance with the embodiment invention described with respect to Figure 1 or Figure 2.

The commercial milking station includes a milk storage (32) which receives milk from a collection point (33) connected to different arrays of milking cups (34a) by a number of collection manifolds (35) and claws (34b).

During the cleaning cycle cleaning liquid is fed to the cleaning system and air is injected as described above to produce pulses of accelerated cleaning liquid 15 which are fed downstream to the collection point (33) which during operation of °.:the cleaning system (31) distributes the pulses of cleaning liquid to the manifolds (35) and milking cups (34a).

A cleaning system suitable for use with multiple effect evaporators will now be ooooo described with reference to Figure 4 of the drawings.

The cleaning system (40) is connected to a holding tube (41) for a multiple *effect evaporator. The holding tube (41) may be of any suitable diameter such as an internal diameter of 250mm.

A product line (42) is provided for transfer of the product to be evaporated such as milk, during normal operation. The product transfer line is generally of smaller diameter than the holding tube (for example 75mm diameter). The cleaning system pipework (43) is connected in parallel with the product transfer line (42) and is provided with air injection means an upstream non-return valve (45) and non-return valve (46) downstream of the air injection means (44).

A valve (47) is also provided in the product transfer line immediately upstream of the downstream connection (48) with the cleaning system pipework (43).

w:,eanniespeciest47289.doc 11 The cleaning system pipe narrowingly tapers adjacent the connection (48) and the product line immediately downstream (48a) of the connection (48) expands to provide a venturi at the connection (48).

The product line is fed by a pump (49) in the product line upstream of the cleaning system pipe (43).

The system is operated to clean multiple effect holding tubes by a two step process which will now be described.

Step 1. Cleaning system upstream valve (45) and downstream valve (46) are opened and the section of the cleaning system pipe between valves (45, 46) allowed to fill with cleaning solution. During this time the head on the pump (49) is reduced and the cleaning system pipe fills in a few seconds.

:O :Step 2. Upstream valve (45) is shut and a predetermined volume of compressed air is injected at injection means Liquid in the cleaning :system pipe (43) is rapidly accelerated and pulses through the system of holding tubes The reduction of pressure at the downstream connection (48) of the cleaning pipe (43) to product transfer line (42) allows the pump to continue pumping liquid. The frequency and amplitude of the cycle times is controlled by a small PLC and is tuned to the configuration of the pipe (41) and vessels being cleaned. Should the head on the pump (49) increase significantly the cycle time is scheduled so that upstream valve (45) opens the cycle repeated.

The cost of the system is relatively cheap but the benefits in terms of a significant reduction in cleaning time and solution requirement to carry out the same degree of cleaning are significant. To clean the holding tubes using the system may require up to 500 litre pressure cylinder to store the required quantity of air.

The volume of the stored compressed air required reduces as the frequency of the pulse increases and amplitude of volume of each plug of liquid decreases.

w:'jeannie specJs%847289.doc 12 The system of Figure 4 can also be operated by an alternative method which will now be described.

Upstream and downstream valves (45, 46) remain closed and air enters air injection means (44) until a desired pressure is obtained and downstream valve (46) is opened. This mode of operation enables high velocities to be obtained and would be used when high exit velocities are required for example in cleaning spray balls and vessels supplied with spray balls and for cleaning spray dryers using a cleaning nozzle.

The continuous operation of the cleaning system relies on the balance of the velocity and pressure head and flow continues whilst the velocity head exceeds the pressure head.

If upstream and downstream valves (45, 46) were non-return valves, upstream valve (45) would be opened until air enters air injection means (44) and upstream valve (45) opened again when entering air at air injection means (44) is stopped and pressure in the product line (42) exceeds the pressure in the r o cleaning pipe (43).

Similarly downstream valve (46) is open whilst pressure in the cleaning pipe is greater than pressure in the product line product transfer line valve (47) shuts when pressure at P3 or P1 is greater than the pressure at product transfer line valve Under these conditions the flow of liquid from the pump (49) is continuous and air being compressible minimises the occurrence of water hammer.

Pulses of cleaning liquid were produced by the above described system which were accelerated from in the range 4 to 6 m/s normally produced by the pump to within the range of 10 to 30 m/s. The size of the air space or liquid pulse produced by injection of gas can be changed in accordance with frequency of injection. The accelerated cleaning liquid moves at high velocity and the accelerated pulses vary in comparison from gas to a mixture of gas and liquid to w:Jeannie'species47289.doc 13 liquid. The pulses produce a scouring effect and is highly effective in removal of soil.

The system of the invention may also be used to provide purging of product prior to cleaning and improve product recovery by minimising dilution.

Figure 5a shows an embodiment of the system of the invention (51) which may be used with a milking apparatus of the type shown in Figure 3.

The system (51) includes a transfer conduct (52) a pump (53) upstream of conduit (52) and air injection means (54) for injecting a pulse of air into the transfer conduit A non-return valve (55) is provided upstream of the air injection means (54) to produce acceleration of liquid in the downstream direction.

The operation of the embodiment will be described with reference to Figure and Figure 3. It will be understood that in this embodiment the apparatus of the invention shown as 36 in Figure 3 is replaced with the system (51) discussed above.

S" In operation the cleaning liquid is pumped by pump (53) into transfer conduit (52) which is continuous with conduit (41) shown in Figure 3. The cleaning liquid is pumped into the collection point (33) and manifold (35) and fill the claws (34b) until it runs from the milking cups (34a) as shown in Figure o0 The pump (53) is shut off and non-return valve (55) is closed. Air is injected under pressure by injection means (54) into the transfer conduit (52) and forces cleaning liquid into the claws under pressure. Turbulent flow produced in the claws is shown in Figure The highly turbulent flow in the claws provides cleaning of all inner surfaces.

Referring to Figure 6 there is shown a modification of the cleaning system of Figure 1 wherein the injection means (6a, 6b) includes means for providing a vapour or mist of cleaning agent in the gas to be injected.

w:jeanniespeciest847289.doc 14 Respective injection means include a dosing tank (60a, 60b) for containing a cleaning agent such as acid, alkali or detergent. Different cleaning agents may be used for each injection means (6a, 6b).

Cleaning agent is delivered from the dosing tanks (60a, 60b) into a compressed air injection line (61a, 61b) via liquid line (62a, 62b). The injection line may be provided with a valve such as a manual control valve (63a, 63b) to regulate the injection of air. Delivery of cleaning agent from the dosing tank (60a, 60b) is controlled by control valve (64a, 64b). The compressed air line (61a, 61b) is fed with a supply of compressed food grade air from air supply (64) under control of a valve (66a, 66b).

The system may be operated to provide delivery of a cleaning agent from the o0o0 dosing tank (60a) into one of the conduits in parallel without co injection of gas.

0 The mixture of cleaning agent and cleaning liquid (57) may then be drawn into :i the downstream position by venturi action produced by liquid accelerated in O other conduits (5b, 5c) in parallel. Alternatively in addition cleaning agent delivered from a dosing tank (50b) may be admixed with air and injected by 000000 injection line (51a, 51b) into one or more of the conduits in parallel (5b) and provide pulses of vapour/gas mixture (58) in the cleaning liquid.

O 9000 The down stream portion of the cleaning system may be connected to a spray nozzle for directing cleaning liquid onto the apparatus to be cleaned or 25 other application devices such as spray balls. The down stream portion may also be provided with a manifold having a plurality of branches for allowing cleaning liquid to be diverted to a range of applications. One example of a manifold system is discussed above with reference to figure 3.

Food grade air delivered from air supply (54) is used to: Pulsate the water flow in the downstream portion of the transfer line Increase the velocity of the liquid in downstream portion of the transfer line w:yeannie'speces\47289,doc Deliver the cleaning reagent as a gas pulse containing mist of controlled concentration.

The action of the gas injection means (6a, 6b) Increases the turbulence hence mechanical energy and cleaning action; and enables lines to be quickly and completely purged of product or cleaning solution thus reducing downtime.

The cooperation of the dosing tank (50a, 50b) with the gas injection means results in injection of the cleaning reagent into the air stream and creates a vapour mist. This enables the concentrate to be applied to the surface of the equipment to be cleaned in either a concentrated form or partially diluted depending on the requirements. The concentrated vapour mist wets the 15 surface and rapidly diffuses into the food soil. The ratio of reagent concentrate to air to solvent (water) can be controlled using a water atomiser but in most situations the normal action of the QKWM via the timer will regulate the concentration of cleaning reagent deposited on the surface. In the case of cleaning pipes and surfaces with milk soil, the following sequence is typical: Step 1: Lines purged of milk product (using food grade air) Step 2: Lines rinsed with a mixture if predominately air and water.

Step 3: The cleaning reagent is injected from dosing tank (50b) into the air stream by gas injection means (6a, 6b) for a period of time required to wet all surfaces to be cleaned (typically this takes at least two minutes). The quantity of water used is preferably just sufficient to allow complete diffusion of the cleaning reagent.

Step 4: The system may then be allowed to rest for up to two minutes.

Step 5: A mixture of air and water is pulsated through the system for two minutes and the amount of water increased to ensure all the reagent and soil associated with the reagent is removed.

The above is repeated using other chemical reagents acid wash) as required to remove other soil components. The above process can be programmed using a small PLC. The process described would find application w:)eannlei\spedwes47289.doc 16 in situations where cleaning of pipelines and process vessels is carried out and has specific advantages when pipelines enlarge such as holding tubes and multiple effect evaporators and rotary dairies for milking cows where a pipeline enters a distributor which supplies up to 100 lines which connect to the "claws".

The cleaning system may be used to apply cleaning liquid to equipment using any suitable means such as a nozzle, spray ball or other spray device. When using a spray ball the diameter of the spray arc was increased by up to percent depending on the pressure of air used. Above a certain pressure the generation of mist was more than desirable.

The system may be provided with means for purging gas from the transfer line.

As gas purging line (70) may be provided in the downstream portion of the transfer line. Alternatively as shown in Figure 7 the conduits in parallel (5a, 15 comprising injection means (6a, 6b) may be provided with a gas purge line

S

(71a, 71b) downstream of the air injection means (6a, 6b). The gas purging line :i (71a, 71b) is generally closed by a controllable valve (72a, 72b) which may cooperate with air injection means to open and allow air to be selectively removed from the conduits (5a, 5b). The gas purging line (71a, 71b) may be 20 operated so as to control the amount of air in the downstream portion to provide a gas to liquid ratio of from 100:0 to 10:90. Solonoid valves are particularly useful to allow time gaps between operation of the air injection valve (66a, 66b) and opening of the purge line valve (71a, 71b).

25 The actual consumption of chemical and mechanical energy plus water is dependent upon several failings but we have noted the following that saving provided by using the pulsed system of the invention cleaning chemical savings water savings 60%, downtime reduction range from 50 to 200%.

One of the significant advantages of the system of the invention is that it allows the volume of cleaning liquid and the amount of chemicals to be minimised by substantially increasing the activity of the cleaning liquid generally by 200 to 300%. This reduces chemical handling and wastage typically to less than half and water requirement is generally less than half that which is otherwise w:qeanniespecies547289.doc 17 required. The method is particularly useful when pipeline diameter increases significantly such as in the holding tubes of multiple effect evaporators.

The system of the invention is easy to use and is reliable and inexpensive producing significant advantages in cleaning efficiency.

C

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Claims (19)

1. A method of cleaning industrial food processing equipment or components thereof comprising applying a cleaning liquid to the food processing equipment or components thereof wherein the cleaning liquid is fed to the equipment or components through a transfer line provided with a means for injecting gas under pressure to the transfer line and wherein one or more pulses of gas are injected into the transfer line under pressure thereby accelerating the cleaning liquid, to increase the force with which the cleaning liquid is applied to processing equipment or components thereof.

2. A method according to claim 1 wherein a plurality of pulses of compressed gas are injected into the transfer line. 15

3. A method according to claim 1 wherein the transfer line includes a o °o:portion upstream of the injection of said one or more pulses, said upstream portion including a valve for inhibiting back flow of cleaning liquid.

4. A method according to claim 1 wherein the liquid transfer line comprises 20 an accelerator portion including at least two conduits in parallel wherein at least one of the conduits in parallel includes means for injecting gas under pressure and valve means for inhibiting back flow upstream of the means for injecting gas under pressure. S. 25

5. A method according to claim 4 wherein the accelerator portion includes C °o at least three conduits in parallel including at least two conduits each provided with gas injection means and a non-return valve upstream of the gas injection means and at least one further conduit for use in transfer of a food product during a food processing operation of the food processing apparatus or component thereof.

6. A method according to any one of claims 1 to 5 wherein a cleaning agent is mixed with the gas under pressure prior to injection into the transfer line to w:'eannie\specdesO647289.doc 19 provide injection of one or more pulses of gas containing a vapour of cleaning agent.

7. A method according to any one of claims 1 to 6 wherein compressed air is injected into the transfer line.

8. A method according to claim 1 wherein the method includes pumping cleaning liquid through the transfer line and injecting said one or more pulses of gas to increase the velocity of the cleaning liquid in the transfer line downstream of the injection by at least 100%.

9. A method according to claim 1 wherein the means for injecting gas under pressure provides pulses of gas with a frequency in the range of from 5-20 pulses per minute. es..

10. A method according to claim 1 wherein the ratio of the volume of gas in the transfer line to the volume of liquid in the transfer line is in the range of from 4:1 and 1:10 down stream of the injection. lO°

11. A method according to claim 1 when used in cleaning equipment for f. processing dairy products.

"12. A system for cleaning food processing equipment or components thereof the system comprising a transfer line for applying cleaning liquid to the food 25 processing equipment or components thereof and means for injecting one or o more pulses of gas under pressure into the transfer line to accelerate the cleaning liquid applied to the food processing equipment or components thereof.

13. A system for cleaning according to claim 12 wherein the transfer line further comprises a portion upstream of the means for injecting one or more pulses of gas under pressure wherein the upstream portion includes a non- return valve. w:eannie\species\847289.doc

14. A system for cleaning according to claim 12 and claim 13 wherein the transfer line includes an accelerator portion comprising at least two conduits in parallel wherein at least one of said conduits is provided with said means for injecting one or more pulses of gas under pressure and a non return valve upstream of said means for injecting one or more pulses of gas under pressure.

A method according to claim 15 wherein the accelerator portion includes at least three conduits in parallel including at least two conduits each provided with gas injection means and a non-return valve upstream of the gas injection means and at least one further conduit for use in transfer of a food product during operation of the food processing apparatus or component thereof.

16. An apparatus according to claim 12 wherein the means for injecting gas 6o. 15 under pressure cooperates with a cleaning agent storage means to produce a :vapour of cleaning agent in said one or more pulses of gas. S.

:17. An apparatus for cleaning according to claim 12 wherein the transfer line feeds cleaning liquid to provide cleaning of commercial milking equipment.

18. An apparatus according to claim 12 wherein the transfer line feeds cleaning liquid to provide cleaning of a multiple effect evaporator or component ".thereof. *OII 25

19. An apparatus according to claim 12 wherein the liquid transfer line is lOll 0 provided with a manifold downstream of the means for injecting one or more pulses of gas under pressure said manifold including branches for applying cleaning liquid to different equipment components. .DATED: 5 July, 2001 PHILLIPS ORMONDE FITZPATRICK Attorneys for: UNSDALE PTY LTD w:jeanniespecis\647289.doc