AU2004202500A1

AU2004202500A1 - Exhaust cleaning system

Info

Publication number: AU2004202500A1
Application number: AU2004202500A
Authority: AU
Inventors: Mark Creelman; Ian North
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-06-06
Filing date: 2004-06-07
Publication date: 2004-12-23

Description

EXHAUST CLEANING SYSTEM Field of the Invention This invention relates to a system of cleaning exhausts. It is particularly related to exhaust systems of oil grillers or fryers used for food cooking in restaurants and take away venues but are not limited to such use.

Background Art A deep fryer is generally a large vat structure of oil which is heated to allow baskets of food to be inserted to deep fry the food. The top of the vat structure is open and therefore requires an overhanging exhaust system or hood including an impeller system drawing the cooking fumes out of the kitchen, into a duct leading to an external exit for expelling the fumes externally. In commercial sized venues the external exit of the duct is often on the roof and a tortuous duct system feeds through the ceiling cavity. To provide sufficient power the exhaust impeller is mounted at the external exit on the roof.

Such a system builds up substantial grease, oil film and other surface sticking material onto the internal surface of the tortuous duct system. Clearly in food systems in restaurants and take away venues it is important that such material does not remelt and fall back down into the cooking vat polluting food products.

A usual method of cleaning such a system is to firstly roll away the vat from under the exhaust system. Secondly the impeller system at the top of the duct is moved away.

Thirdly heated water is flushed down the duct. This substantially cleans the duct leaving a substantial mess on the floor of the kitchen which can then take hours to clean. Basically, this system is as simple as going to the roof to the exhaust fans, lifting the fans to expose the exhaust ducts and getting a hot garden hose and sending large amounts of water down the pipes to the kitchen below.

This basic hot water exhaust cleaning system takes between 3 and 4 hours to finish and can only be done when the stores are shut due to the huge build-up of grease and filth that has coagulated and finishes on the kitchen floor inside the restaurant.

The problems with this system include the system being expensive as it is labour intensive, time consuming. Also workplace becomes unsafe due to slippery floor from the grease and water. However the system is not sufficient anyway as the water can simply not get into all the bends and corrugated crevices. It is environmentally unfriendly due to the huge volume of water wasted and chemicals used. Further the system is not customer friendly due to management having to be in the store all night to supervise. Generally, the kitchen is left unclean after the workers leave and requires more cleaning by set-up crew and management Other problems with such systems is that the oil vat is usually heated by three phase electric supply which is located near the usual cooking position of the vat and therefore under or near the exhaust fan. The large quantities of water can and often find their way to the electric system causing short circuits. Substantial time and costs is needed to be expended to correct the electrics. If precautions are not taken beforehand, could become even more costly due to water splashing up into the 3 Phase electrical system installed for the vats and grills.

With all these above problems, the exhaust cleaning is delayed as long as possible and beyond acceptable time limits. Over time more electricity is used in running the exhaust fans due to lag time in between cleans. This creates another more dangerous issue, a fire hazard starting inside the stacks due to the large build-up of combustible greasy fuel.

It is therefore an object of the invention to provide a better cleaning system which overcomes or at least ameliorates the problems of the prior art.

Summary of the invention In accordance with the invention there is provided a method of cleaning exhaust ducts by providing a substantially sealed flush of the duct with a flushing material.

The sealing can be reversible selective sealing of the lowest point of the duct by a closure structure when a cleaning process is required.

The flush can include entry of the flushing material from the uppermost point of the duct.

The flush can include introduction of flush material progressively down the duct by a hosing system having a nozzle outlet at its end. The nozzle outlet can include means to provide circumferential cleaning of the internal walls of the duct regardless of their shape. The means can be effect a rotation of the nozzle. In another form the nozzle provides a circumferential spray.

The hosing system can be connected to a feed means which feeds the hose at a required rate. The rate can be predetermined dependent on the nozzle outlet mechanism for sufficient circumferential cleaning. The nozzle outlet can include a jet system to provide assistance to the progression of the hosing system down the duct.

The hosing system can include an associated brush mechanism to assist cleaning of the duct walls.

The flush can include a controlled exit of flushing liquid. This can include a flush channel system leading from the sealed duct through a defined channel. The defined channel can be a channel through the closure structure.

Alternatively the defined channel can be through an outlet from the lower end of the duct adjacent the closure structure. The defined outlet can include valving means or tap means.

The invention also provides a closure structure for use in reversible selective sealing of the lowest point of the duct when a cleaning process is required, the closure structure including one or more shaped bodies having a combined external circumferential shape substantially corresponding to the internal shape of the lowest end or near the lowest end of the exhaust duct.

The closure structure can include or be associated with locking means for securely positioning the closure structure in the lower end of the duct.

The locking means can be the same means that hold closing filter grilles that are usually positioned in the lowest end of the duct when overhanging the oil vat in a cooking position. The filter grilles provide a coarse filter of particulate matter in the cooking fumes and provide a visual closure of the exhaust duct.

In another form the locking means can be mounted on the closure structure and engage with the lower end of the duct or peripheries to hold the closure structure in position. One type could be a closure structure having resilient circumferential edging with a deviation means for urging the edging outwards to provide a frictional hold of the closure structure within the duct opening or periphery. The deviating means can be a cam means. Another type can be moveable protruding means mounted on the closure structure for selectively moving the protruding means in engagement with the sides or for receipt in opening in the duct or duct opening or periphery for holding the closure structure in position.

The position of the closure structure needs to be sufficient to seal the lower opening of the duct or opening or hood feeding to the duct. The closure structure can therefore include circumferential resilient material for ensuring a tight sealed fit.

The closure structure can be made of a non porous heat resistant material for sealing the base of the duct and preventing the heated flushing liquid from exiting the duct until required and in the manner required.

Also in accordance with the invention there is provided an exhaust cleaning system for use on a exhaust system having an exhaust duct with an opening that is able to be adjacent or overhang a food cooking source with a duct leading therefrom to an external outlet and with an exhaust fan impeller mounted at or near the external outlet wherein the exhaust cleaning system includes the steps of: a) providing one or more closure structures which together are sized to be able to block the entrance of the exhaust opening or overhanging hood leading to the opening, b) provide an inlet on one side of the closure structure feeding therethrough to an outlet on the opposing side of the structure; c) positioning the closure structures in the exhaust opening or overhanging hood leading to the opening to substantially seal a lower point of the exhaust duct with the inlet of the closure structure feeding from the duct and the outlet leading outwardly from the duct, d) providing an outlet flow channel to receive fluid flow from the outlet of the closure structure e) applying cleaning fluid into the exhaust duct to clean the internal walls of the duct f) controlling the exit of the liquid after cleaning from the outlet of the closure structure.

It can be seen that the invention provides one or more of the following advantages: i. Less time consuming only takes 1 hour to complete the cleaning of all exhaust ducting and exhaust fans ii. Less labour intensive requires 2 persons for shorter period of time doing less work (cleaning up) iii. Cleaner all waste build-up is washed away down the drainage pipes iv. More cost efficient less time due to no clean up, less water wastage, less time on the roof v. Environmentally sound less water used and no chemicals used vi. No require the store to supervise all night procedure can be done in 1 hour and doors do not need to be closed vii. Safer due to no water on the ground, no water splashed'on the electrical components, no Occupational Health Safety issues due to no washing up viii. Finally, the actual job is far superior as the hot water jet spray cuts into all the build-up on the inside of the ducting work and it doesn't matter whether the ducting twists or turns all over the place as the pressure spray keeps the spray nozzle in the centre of the ducting Brief Description of the Drawings In order that the invention can be more readily understood an embodiment will be described by way of illustration only with reference to the drawings wherein: Figure 1 is a diagrammatic drawing of a standard exhaust duct system used with food systems to which the exhaust cleaning system of the present invention can be applied.

Description of a Preferred embodiment of the Invention Referring to Figure 1 there is shown a standard arrangement for exhaust ducts. A deep fryer 12 being a large vat filled with oil which is heated to allow baskets of food to be inserted to deep fry the food is mounted on wheels in a kitchen. The top of the vat structure is open and therefore requires an overhanging exhaust system. This is provided by a hood 14 connected to the bottom of a duct 13 that leads beyond the roof to an impeller system 21 and an exit 17 external of the building. The impeller 21 draws the cooking fumes out of the kitchen, into the duct 13 leading to an external exit for expelling the fumes externally. A motor is mounted on the roof to drive the exhaust impeller. Such a system builds up substantial grease, oil film and other surface sticking material onto the internal surface of the tortuous duct 13.

The method of cleaning exhaust ducts in accordance with the invention provides a sealed flush of the duct.

Firstly the deep fryer vat 12 is disconnected from the three phase electric supply. The vat 12 is then wheeled out of the way and can be separately cleaned.

Filters extending across the entry 16 of the hood 14 are removed for separate cleaning.

A number of closure structures are provided which together are sized to be able to block the entrance of the exhaust hood 14 leading to the duct 13.

The closure structures are rectangular shapes substantially corresponding to the rectangular shapes of the filters that have been removed. This allows for reversible selective sealing of the lowest point of the duct when a cleaning process is required.

The closure structure is associated with locking means for securely positioning the closure structure in the lower end of the duct. These locking means are the same means that hold closing filter grilles that are usually positioned in the lowest end of the duct when overhanging the oil vat in a cooking position. The fitting of the closure structure needs to be sufficient to seal the lower opening of the duct or opening or hood feeding to the duct. The closure structure therefore includes circumferential 6 resilient material for ensuring a tight sealed fit.

The closure structure is made of a non porous heat resistant material. This can be an aluminium right angled hollow structure sized similar to the filters they are replacing.

It also has an inlet on one side of the closure structure feeding therethrough to an outlet on the opposing side of the structure. This flow path is a tube extending therethrough.

Therefore the next step is to position the closure structures in the exhaust opening hood 14 to substantially seal a lower point of the exhaust duct 13 with the inlet of the closure structure feeding from the duct 13 and the outlet leading outwardly from the duct. This seals the base of the duct and preventing the heated flushing liquid from exiting the duct until required and in the manner required. A tube is connected to the outlet of the closure means to provide an outlet flow channel to receive fluid flow from the outlet of the closure structure.

The user of the system can then proceed to the roof 15 at which point the impeller 21 in its frame 22 can be moved out of the flow by rotation around its pivot mounting 23.

The user can apply cleaning fluid into the exhaust duct to clean the internal walls of the duct. The system allows control of the exit of the liquid after cleaning from the outlet of the closure structure.

The flush include introduction of flush material progressively down the duct 13 from the top exit 17 by a hosing system having a nozzle outlet at its end. The nozzle outlet can include means to provide circumferential cleaning of the internal walls of the duct regardless of their shape. The means can be effect a rotation of the nozzle.

The hosing system is connected to a feed means which feeds the hose at a required rate. The rate is predetermined dependent on the nozzle outlet mechanism for sufficient circumferential cleaning. The flush includes a controlled exit of flushing liquid. This can include a flush channel system leading from the sealed duct through a defined channel. The defined channel can be a channel through the closure structure. The hosing system is high pressure at about 2000psi (140 BAR) of 800 hot 7 water. The heat and high pressure are used to break down the fat and grease residue built up on the inside surfaces of the duct 13. The waste material is pushed down the exhaust system to the bottom of the duct 13 at the entry 16 so as to be flushed through to the connected hose from the outlet of the closure means. The hose has a high pressure rotating head that assists in dragging the hose down the duct as it cleans.

This process is required once or twice depending on the last time the exhaust ducts were cleaned and one process only takes around two minutes.

Example 1.

In one particular procedure requires the following components: High Pressure Hot Water Hose Gerni Specially constructed rotating "pull-thru" nozzle and regular spray nozzle to fit Gerni 0 Exhaust ducting safety splash plate o Mesh or Flameguard filter sized containment plates with attached rotating spray nozzles to fit Gernmi Containment plate gaskets Mesh or Flameguard filter sized containment plates with discharge outlet Discharge hose with grease trap drainage connection attachment Leakage container with dispensing hose (not required on all exhaust hoods) A two-way hands-free communication device The procedure uses the following steps: 1. The commercial food preparation kitchen orders an exhaust system clean or as in the case of a fast food chain like McDonald's, is on a pre-arranged rotational exhaust system planned maintenance cleaning contract.

2. If it is a first clean, filter, filter hood and drainage specifications are assessed and measured so containment plates, containment gaskets and discharge hoses can be selected or made to fit into place.

3. A pre-arranged time is agreed upon to suit both parties. Due to the minimal discomfort the cleaning procedure has on the stores, this time can be organised for a quiet time when the store is still open. Also, this exhaust cleaning system only requires the exhaust fan that is being cleaned be turned off, not both at once.

4. Once ready, the first exhaust fan that is being cleaned is turned off.

5. The everyday filters are replaced with the pre-measured containment gaskets and containment plates. The discharge hose that diverts the waste to the drain is connected. A leakage container can be fitted as required but may not be required on some hood set-ups.

6. A high pressure hose is connected to a water supply and fitted with a spray nozzle, and then the operator heads to the roof and prepares the exhaust fan ready for cleaning.

7. Once both cleaners in the store and operator on the roof are ready, the operator starts cleaning the exhaust fan. All built-up grease in and around the fan housing and blades, once removed, simply makes its way down the exhaust ducting to the bottom.

8. After cleaning this exhaust fan, the safety splash plate is put into position.

9. The operator changes the nozzle on the high pressure hose to the specially constructed rotating "pull-thru" nozzle then starts the cleaning on the ducting work. This requires the operator to guide the high pressure hose down the opening as it pulls itself through the exhaust ducts. This action may be repeated as many times as is required. The discharge cleaner lets the operator know when the water runs clear via a two-way communication system.

Once satisfied, the operator connects the high pressure hose to the spray nozzle containment plates and cleans the insides of the exhaust hood until clean.

11. The same procedure is then replicated for the other exhaust fan, duct work and exhaust hood.

All work can be completed within one hour.

It should be noted that the above description is of a preferred embodiment of the invention. Clearly variations understandable by a person skilled in the art without any inventiveness are included within the scope of this invention.

Claims

1. A method of cleaning exhaust duct by providing a substantially sealed flush of the duct with a flushing material.

2. A method according to claim 1 wherein the cleaning is in situ with a reversible selective substantial sealing of the lowest point of the duct by a closure structure.

3. A method according to claim 1 or 2 wherein the flush includes entry of the flushing material from the uppermost point of the duct.

4. A method according to claim 1, 2 or 3 wherein the flush includes introduction of flushing material progressively down the duct by a hose system having a nozzle outlet at its end.

A method according to claim 4 wherein the nozzle outlet includes nozzle means to provide circumferential cleaning of the internal walls of the duct regardless of their shiape.

6. A method according to claim 4 wherein the nozzle means effects a rotation of the nozzle.

7. A method according to claim 6 wherein the nozzle means provides a circumferential spray.

8. A method according to any one of claims 4 to 7 wherein the hose system is connected to a feed means which feeds the hose at a required rate.

9. A method according to claim 8 wherein the rate is predetermined dependent on the nozzle outlet mechanism for sufficient circumferential cleaning.

A method according to any one of claims 4 to 9 wherein the nozzle outlet includes a jet system to provide automatic assistance to the progression of the hosing system down the duct.

11. A method according to any one of the preceding claims wherein the hosing system includes an associated brush mechanism to assist cleaning of the duct walls.

12. A method according to any one of the preceding claims wherein the flush includes a controlled exit of the flushing material.

13. A method according to claim 12 wherein the flush includes a flush channel system leading from the sealed duct through a defined channel.

14. A method according to claim 13 wherein the defined channel is a channel through the closure structure.

A method according to claim 13 wherein the defined channel is an outlet extending from the lower end of the duct adjacent the closure structure.

16. A method according to any one of claims 13 to 15 wherein the defined outlet includes valving means or tap means.

17. A closure structure for use in reversible selective sealing of the lowest point of the duct when a cleaning process is required, the closure structure including one or more shaped bodies having a combined external circumferential shape at least substantially corresponding to the internal shape of the lowest end or near the lowest end of the exhaust duct.

18. The closure structure according to claim 17 which includes or is associated with locking means for securely positioning the closure structure at the lower end of the duct.

19. The closure structure according to claim 18 with the locking means corresponding to the holding means that holds closing filter grilles that are 11 usually positioned in the lowest end of the duct when overhanging the heating means for fumes to be exhausted.

The closure structure according to claim 19 with the filter grilles providing a coarse filter of particulate matter in the cooking fumes and providing a visual closure of the exhaust duct.

21. The closure structure according to claim 18 with the locking means mounted on the closure structure and to engage with the lower end of the duct or peripheries to hold the closure structure in position.

22. The closure structure according to claim 21 having resilient circumferential edging with a deviation means for urging the edging outwards to provide a frictional hold of the closure structure within the duct opening or periphery.

23. The closure structure according to claim 22 wherein the deviating means is a cam means.

24. The closure structure according to claim 21 having a moveable protruding means mounted on the closure structure for selectively moving the protruding means in engagement with the sides or for receipt in opening in the duct or duct opening or periphery for holding the closure structure in position.

The closure structure according to claim 14 with the closure structure including circumferential resilient material for ensuring a tight sealed fit such that the positioning of the closure structure enables sufficient sealing of the lower opening of the duct or opening or hood feeding to the duct..

26. The closure structure according to anyone of claims 17 to 25 with the closure structure made of a non porous heat resistant material for sealing the base of the duct and preventing the heated flushing liquid from exiting the duct until required and in the manner required.

27. An exhaust cleaning system for use on a exhaust system having an exhaust duct with an opening that is able to be adjacent or overhang a food cooking source with a duct leading therefrom to an external outlet and with an exhaust fan impeller mounted at or near the external outlet wherein the exhaust cleaning system includes the steps of: a. providing one or more closure structures which together are sized to be able to block the opening of the exhaust duct or overhanging hood leading to the opening, b. providing an inlet on one side of the closure structure feeding therethrough to an outlet on the opposing side of the structure; c. positioning the closure structures in the exhaust opening or overhanging hood leading to the opening to substantially seal a lower point of the exhaust duct with the inlet of the closure structure feeding from the duct and the outlet leading outwardly from the duct, d. providing an outlet flow channel to receive fluid flow from the outlet of the closure structure e. applying cleaning fluid into the exhaust duct to clean the internal walls of the duct f. controlling the exit of the liquid from the outlet of the closure structure.

28. An exhaust cleaning system according to claim 27 wherein the flush includes introduction of flushing material progressively down the duct by a hose system having a nozzle outlet at its end.

29. An exhaust cleaning system according to claim 27 wherein the nozzle outlet includes nozzle means to provide circumferential cleaning of the internal walls of the duct regardless of their shape.

An exhaust cleaning system according to claim 29 wherein the nozzle means effects a rotation of the nozzle.

31. An exhaust cleaning system according to claim 29 wherein the nozzle means provides a circumferential spray.

32. An exhaust cleaning system according to claim 29 wherein the hose system is connected to a feed means which feeds the hose at a required rate.

33. An exhaust cleaning system according to claim 32 wherein the rate is predetermined dependent on the nozzle outlet mechanism for sufficient circumferential cleaning.

34. An exhaust cleaning system according to claim 33 wherein the nozzle outlet includes a jet system to provide automatic assistance to the progression of the hosing system down the duct.

An exhaust cleaning system according to claim 34 wherein the hosing system includes an associated brush mechanism to assist cleaning of the duct walls.

36. A method of cleaning exhaust ducts substantially as hereinbefore described with reference to the drawings.

37. A closure structure substantially as hereinbefore described with reference to the drawings.

38. An exhaust cleaning system substantially as hereinbefore described with reference to the drawings. Mark Creelman and Ian North by their patent attorneys PIPERS MILLS OAKLEY Patent Attorneys 7 June 2004