Ultra-violet recirculating exhaust hood system

Abstract

A recirculating hood for exhausting fumes from a food cooking apparatus features a housing defining an interior chamber within which is positioned a filter system and an ultraviolet lamp. A fan exhausts fumes from the cooking apparatus through an inlet opening into the interior chamber and draws the fumes through the filter system and past the ultra-violet lamp. As a result, the fumes are filtered and irradiated with ultra-violet light before they are returned to the room space that the hood shares with the food cooking apparatus.

Description

BACKGROUND

The field of the invention relates generally to food cooking equipment and, more particularly, to a recirculating exhaust hood system and method for food cooking equipment where the hood features an ultra-violet light for treating air flowing through the hood.

Recirculating hoods (also known as ventless hoods) for exhausting smoke and fumes from food cooking equipment, such as stoves, ovens, fryers, grills and griddles have become very popular because they overcome many of the problems associated with systems that vent fumes out of a building or the like. More specifically, while the “venting” systems that direct fumes out of a building provide an adequate quality of air inside of the building, the atmosphere surrounding the building from which such cooking fumes are discharged may not meet air quality standards. In addition, in many buildings, such as high-rise buildings, the cost of providing a system that vents fumes to the atmosphere can be very high due the cost of ductwork leading from the cooking equipment to the exterior of the building.

Recirculating hoods clean the grease and aroma laden fumes from the cooking equipment before the fumes are discharged or re-circulated back into the room. While prior art systems have performed well in filtering grease from the fumes, room for improvement exists in terms of deodorizing the fumes. Furthermore, in order for the recirculating hoods to continue to function safely and efficiently, it is desirable to avoid excessive grease buildup in the hoods. As a result, a need exists for a system and method that improves deodorizing of the fumes exhausted by recirculating hoods and/or eliminates or reduces grease buildup in the hoods.

SUMMARY

The present invention includes:

In one embodiment, a recirculating food cooking system includes an exhaust hood featuring a housing defining an interior chamber and having an inlet opening. A food cooking apparatus shares a room space with the exhaust hood. A filter and ultra-violet lamp are positioned within the interior chamber of the exhaust hood. A fan is in communication with the interior chamber and draws fumes from the cooking apparatus through the inlet opening and the filter and exposes the fumes to ultra-violet light before exhausting them to the room space.

In another embodiment, a recirculating exhaust hood for exhausting fumes to a shared room space includes a housing defining an interior chamber and having an inlet opening. A filter is positioned within the interior chamber. An ultra-violet lamp is positioned within the interior chamber to provide ultra-violet light within the interior chamber. A fan communicates with the interior chamber and draws fumes through the inlet opening and the filter and exposes the fumes to ultra-violet light before exhausting the fumes into the shared room space.

In still another embodiment, a method of re-circulating fumes from a food cooking apparatus includes the steps of exhausting the fumes from the cooking apparatus, filtering the fumes and exposing the filtered fumes to ultra-violet light. The filtered and exposed fumes are delivered back to a room space within which the food cooking apparatus is positioned.

In still another embodiment, a module for retrofitting an exhaust hood that exhaust fumes from a food cooking apparatus includes a filter and an ultra-violet lamp joined to the filter. The joined filter and ultra-violet lamp adapted to be mounted within the exhaust hood so that fumes traveling through the exhaust hood are filtered by the filter system and exposed to ultra-violet light from the ultra-violet lamp.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevation view, partially broken-away, of a food fryer constructed in accordance with a first embodiment of the present invention;

FIG. 2 is a side elevation view, partially broken-away, of the food fryer of FIG. 1;

FIG. 3 is a front elevation view, partially broken-away, of a docking station constructed in accordance with a second embodiment of the present invention;

FIG. 4 is a side elevation view, partially broken-away, of the docking station of FIG. 3;

FIG. 5 is a top plan view, partially broken-away, of a recirculating hood constructed in accordance with a third embodiment of the present invention;

FIG. 6 is a front elevation view, partially broken-away, of the recirculating hood of FIG. 5;

FIG. 7 is a top plan view of a module constructed in accordance with a forth embodiment of the present invention; and

FIG. 8 is a side elevation view of the module of FIG. 7 mounted in a recirculating hood.

DESCRIPTION OF THE EMBODIMENTS

While embodiments of the invention are described below in terms commercial food cooking equipment, it is to be understood that any embodiment of the present invention could be used with any cooking equipment, including, but not limited to, cooking equipment intended for home use or use in other environments.

In one embodiment, a food fryer is indicated in general at 10 in FIGS. 1 and 2. The food fryer includes a food cooking apparatus, indicated in general at 12, and a recirculating hood, indicated in general at 13. The food cooking apparatus 12 includes frypot, indicated in FIG. 2 at 14 in phantom, the contents of which are heated by a heating element, indicated in FIG. 2 at 16 in phantom. Control of the food fryer is accomplished via control panel 17. In a typical operation, a wire basket containing breaded chicken pieces is lowered into frypot 14 which contains oil heated sufficiently for frying chicken. Apparatus 12 may be operated either pressurized, with a lid covering the frypot, or unpressurized, without using a lid.

The recirculating hood 13 of FIGS. 1 and 2 could alternatively be used with food cooking apparatuses other than fryers including, but not limited to, ovens, stoves, grills and griddles. Examples of such food cooking apparatuses include, but are not limited to, the fryer and oven illustrated and described in commonly owned U.S. Pat. Nos. 4,854,949 and 4,902,316, the disclosures of which are incorporated by reference.

Heated grease-laden air arising from the hot oil in the frypot rises into the path of air being exhausted through a filter system, indicated in general at 18, by exhaust fan 20 (FIG. 2). Air exiting the filter system is irradiated with ultra-violet (UV) light from UV lamp tube 21 (FIG. 1) prior to traveling into exhaust fan 20. Recirculating hood 13 features a housing 22 that defines an interior chamber 23 having an inlet opening. Filter system 18, exhaust fan 20 and UV lamp tube 21 are positioned within the interior chamber 23 of recirculating hood 13 with the filter system 18 positioned adjacent to the inlet opening. The direction of air circulation is shown by the arrows 25 of FIG. 2.

The filter system 18 may include a grease filter 24, an electrostatic precipitator (or electrostatic air cleaning filter) 26, and a charcoal filter or polysorb filter 28. The filter system may optionally also include a flame arrester. These filters preferably are positioned at an angle between about 5 degrees and 45 degrees to the horizontal, sloping upward and substantially over the frypot. The food fryer may also include a fire extinguisher system of the type illustrated in commonly owned U.S. Pat. No. 4,854,949, to extinguish flames from burning oil should a fire occur.

Grease filter 24, which preferably features baffles, indicated at 32 in FIG. 1, and is preferably constructed of aluminum, condenses the moisture content in the air rising from the frypot into small droplets. The grease filter also traps grease impurities in the air rising from the frypot. Moisture condensed by grease filter 24 drains through channel 34 (FIG. 1) to be collected in container 36 due to the tilted orientation of the filter.

Electrostatic precipitator 26 may be an electronic cell such as is well known in the art. The precipitator is preferably operated at about 90-95% of its capacity.

Charcoal filter 28 may include a perforated case containing granular charcoal. As the heated air passes through the charcoal filter, the air is deodorized. Alternatively, a polysorb filter may be used.

Grease filter 24, electrostatic precipitator 26 and charcoal filter or polysorb filter 28 may be arranged in a sequence different from the one illustrated in FIGS. 1 and 2, if required. The optional flame arrester and grease filter 24 may be combined into a single unit in which case the unit is preferably located in the lowest filter position illustrated for grease filter 24 in FIGS. 1 and 2. Alternatively, the filter system may include only a grease filter, a charcoal filter or polysorb filter or an electrostatic precipitator filter, or in another embodiment, at least one or any two selected from a grease filter, a charcoal filter or polysorb filter and an electrostatic precipitator filter.

In another embodiment, the filter system may include a grease filter and/or a charcoal filter or polysorb filter, but not an electrostatic precipitator filter.

The UV lamp tube receives power from a power supply 37, which may be positioned either outside of the housing 22 of recirculating hood 13, as illustrated in FIGS. 1 and 2, or alternatively within interior chamber 23.

While a UV lamp tube is illustrated in FIG. 1 (and FIGS. 3, 5 and 7), alternative UV lamp types known in the art may be substituted for the UV lamp tube. In addition, while a single UV lamp is illustrated in FIG. 1 (and FIGS. 3, 5 and 7), multiple UV lamps may alternatively be used.

UV wavelengths preferably used for treating the exhausted air flowing through the recirculating hood 13 are in the “C” wavelength range (known in the art as “UVC” light). It is to be understood, however, that UV lights having other wavelengths are within the scope of the invention.

As the air exiting the filter system 18 is irradiated with UV light from UV lamp tube 21, it is believed that a chemical reaction converts some of the grease and fat molecules remaining in the air into water, carbon dioxide and mineral acids. These by-products are then drawn out of the interior chamber of the hood through fan 20. The air is also partially deodorized by the chemical reaction because small particles of pollutants which cause odors are removed.

In a normally operating commercial food establishment, hot grease-laden air continuously flows through the interior chamber 23 of hood 13. The hood also operates in a high temperature environment. Thus, significant accumulation of grease in the hood may create a fire hazard if neglected and not cleaned out. It is believed that UV lamp tube 21 within hood 13 decontaminates the air flowing through the hood's interior chamber to aid in combating this problem and to also assist in deodorizing the air. While the UV lamp tube 21 is preferably positioned on the outlet side of the filter system 18, so that larger grease particles are removed from the air exhausted from the food cooking apparatus, it could alternatively be positioned on the inlet side or between filters.

Fan 20 may be a continuously operating fan, such as a squirrel cage fan. The speed of operation of the fan is preferably such that air flow through all sections of filter system 18 and past UV lamp tube 21 is regulated so that air from the outlet 38 of fan 20 is of good quality. As a result, the air discharged from the recirculating hood 13 may be directed back into the internal room space where the food fryer 10 is being operated. A typical fan operates at 1400 rpm and pulls 1157 cu. ft. air/min. through the fan.

In another embodiment, with reference to FIGS. 3 and 4, a docking station is indicated in general at 40. The docking station includes an enclosure, indicated in general at 41, and a recirculating hood, indicated in general at 43. The enclosure 41 includes a back wall 44 and side walls 45 and 46 that define an interior of the enclosure 47 (FIG. 4). Both the front and bottom of the enclosure are open. As a result, a separate food cooking apparatus, such as a food fryer mounted on wheels, may be rolled into the interior of the enclosure through the open front. Fumes produced by the food cooking apparatus may then be exhausted by the recirculating hood 43.

Like with the recirculating hood 13 of FIGS. 1 and 2, heated grease-laden air arising from the food cooking apparatus rises into the path of air being exhausted through a filter system, indicated in general at 48, by exhaust fan 50 (FIG. 4). Air exiting the filter system is exposed to UV light from UV lamp tube 51 (FIG. 3) prior to traveling into exhaust fan 50. Recirculating hood 43 features a housing 52 that defines an interior chamber 53. Filter system 48, exhaust fan 50 and UV lamp tube 51 are positioned within the interior chamber 53 of recirculating hood 43 and preferably include the same construction details and operate in the same fashion as the corresponding components discussed with respect to FIGS. 1 and 2.

In another embodiment, with reference to FIGS. 5 and 6, a recirculating hood is indicated in general at 60. The recirculating hood 60 is suitable for use with a food cooking apparatus such as an oven, indicated in phantom at 62. Hood 60 features a housing 66 that defines interior chamber 68. As illustrated in FIG. 6, housing 66 features an inlet opening 72 that communicates with the space above the oven. Aroma and grease-laden vapors leaving the oven unit are pulled through opening 72 by forced air circulating fan 74 (FIG. 5). The direction of air circulation is shown by the arrows 75 of FIGS. 5 and 6.

A grease filter 76 is positioned above opening 72 and traps grease and moisture in the exhausted fumes. Grease filter 76 is preferably positioned at an angle to the horizontal between approximately 40 degrees and 60 degrees. As a result, grease and moisture trapped on the filter run down the filter surface and can be collected in a collecting vessel (not shown) positioned below filter 76.

Air passing through grease filter 76 next passes through electrostatic precipitator (or electrostatic air cleaning filter) 78 which is sized and positioned so that air passing through grease filter 76 also passes through electrostatic filter 78. Air leaving electrostatic filter 78 next passes through charcoal filter or polysorb filter 80 which absorbs aromatic impurities in the air. Charcoal filter or polysorb filter 80 is sized and positioned (either vertically or at an angle) so that air passing through electrostatic filter 78 passes through charcoal filter or polysorb filter 80. Air leaving charcoal filter or polysorb filter 80 is exposed to the UV light from a UV lamp tube 82 and, as with the systems of FIGS. 1-4, it is believed that a chemical reaction converts some of the grease and fat molecules remaining in the air into water, carbon dioxide and mineral acids. These by-products are then drawn out of the interior chamber of the hood through fan 74. The air is also partially deodorized by the chemical reaction because small particles of pollutants which cause odors are removed. The air passing by UV lamp tube 82 is pulled by fan 74 through the interior chamber 68 to leave the interior chamber of the hood through fan exit 84 (FIG. 5) which communicates with the air space in the room in which oven 62 is located. Fan 74, grease filter 76, electrostatic filter 78 and charcoal filter or polysorb filter 80 may be similar in construction and operation to the corresponding components used in the food fryer of FIGS. 1 and 2 and the docking station of FIGS. 3 and 4.

In yet another embodiment, a module that may be used to retrofit exhaust hoods is indicated in general at 90 in FIGS. 7 and 8. The module features a pair of electrostatic precipitators (or electrostatic air cleaning filters), illustrated at 92 and 94, that are mounted on one side to a grease filter 96 by supports 97 and 98 (FIG. 8). A UV lamp tube 100 is mounted to the opposite side of the electrostatic precipitators via bracket 102 (FIG. 8). The electrostatic precipitators 92 and 94, grease filter 96 and UV lamp tube 100 may be similar in construction and operation to the corresponding components used in the systems of FIGS. 1-6. Alternatively, the module may also include other filter elements including, but not limited to, charcoal filters or polysorb filters.

As illustrated in FIG. 8, the module may be mounted in a hood, indicated in phantom at 104. The hood 104 may be either a venting hood or a ventless/recirculating hood. The module preferably is mounted so that the grease filter 96 faces the bottom opening of the hood 104 and the UV lamp tube 100 is positioned adjacent to the hood exhaust fan 106. As a result, fumes from a food cooking apparatus positioned under the hood travel the path indicated by arrows 108 in FIG. 8, when the exhaust fan 106 is activated. The fumes are filtered by the grease filter 96 and electrostatic precipitators 92 and 94 and then are treated by UV light from UV lamp 100 in the manner described above for the systems of FIGS. 1-6. Power for the electrostatic precipitators 92 and 94 and the UV lamp 100 is provided by a control box 110 that may be mounted on a wall or other surface near hood 104 and that communicates with the electrostatic precipitators and UV lamp via electrical line 112. The module may be fastened within the hood via screws, clips or other fasteners known in the art.

While embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made therein without departing from the spirit of the invention.

Claims

1. A recirculating food cooking system comprising:

a) an exhaust hood including a housing defining an interior chamber and having an inlet opening;

b) a food cooking apparatus sharing a room space with the exhaust hood;

c) a filter positioned within the interior chamber;

d) an ultra-violet lamp positioned within the interior chamber to provide ultra-violet light within the interior chamber; and

e) a fan in communication with the interior chamber, said fan drawing fumes from the cooking apparatus through the inlet opening and the filter and exposing the fumes to ultra-violet light before exhausting the fumes to the room space.

2. The system of claim 1 wherein the fan is positioned within the interior chamber of the exhaust hood.

3. The system of claim 1 wherein the ultra-violet lamp provides ultra-violet light having wavelengths in the “C” wavelength range.

4. The system of claim 1 wherein the filter is positioned adjacent to the inlet opening so that fumes passing through the inlet opening travel through the filter prior to exposure to the ultra-violet light.

5. The system of claim 1 wherein the filter and the ultra-violet lamp are oriented in the interior chamber of the exhaust hood such that fumes from the cooking apparatus pass through the filter prior to exposure to the ultra-violet light.

6. The system of claim 1 wherein the ultra-violet lamp is a lamp tube.

7. The system of claim 1 wherein the filter includes a grease filter.

8. The system of claim 1 wherein the filter includes an electrostatic precipitator.

9. The system of claim 1 wherein the filter includes a charcoal filter.

10. The system of claim 1 wherein the filter includes a polysorb filter.

11. The system of claim 7 wherein filter further comprises an electrostatic precipitator.

12. The system of claim 1 wherein the food cooking apparatus includes a frypot and a heating element for heating contents of the frypot.

13. The system of claim 1 wherein the food cooking apparatus is an oven.

14. The system of claim 1 further comprising an enclosure featuring back and side walls that define an interior and wherein said food cooking apparatus is removably positioned in the interior of the enclosure.

15. A recirculating exhaust hood for exhausting fumes to a shared room space comprising:

a) a housing defining an interior chamber and having an inlet opening;

b) a filter positioned within the interior chamber;

c) an ultra-violet lamp positioned within the interior chamber to provide ultra-violet light within the interior chamber; and

d) a fan in communication with the interior chamber, said fan drawing fumes through the inlet opening and the filter and exposing the fumes to ultra-violet light before exhausting the fumes into the shared room space.

16. The system of claim 15 wherein the fan is positioned within the interior chamber.

17. The system of claim 15 wherein the ultra-violet lamp provides ultra-violet light having wavelengths in the “C” wavelength range.

18. The system of claim 15 wherein the filter is positioned adjacent to said inlet opening so that fumes drawn through the inlet opening travel through the filter prior to exposure to the ultra-violet light.

19. The system of claim 15 wherein the filter and the ultra-violet lamp are oriented in the interior chamber of the exhaust hood such that fumes are drawn through the filter prior to exposure to the ultra-violet light.

20. The system of claim 15 wherein the ultra-violet lamp is a lamp tube.

21. The system of claim 15 wherein the filter includes a grease filter.

22. The system of claim 15 wherein the filter includes an electrostatic precipitator.

23. The system of claim 15 wherein the filter includes a charcoal filter.

24. The system of claim 15 wherein the filter includes a polysorb filter.

25. The system of claim 21 wherein filter further comprises an electrostatic precipitator.

26. A method of re-circulating fumes from a food cooking apparatus comprising the steps of:

a) filtering fumes from the cooking apparatus;

b) exposing the filtered fumes to ultra-violet light; and

c) delivering the filtered and exposed fumes back to a room space within which the food cooking apparatus is positioned.

27. The method of claim 26 wherein said step c) comprises exposing the filtered fumes to ultra-violet light having wavelengths in the “C” wavelength range.

28. The method of claim 26 wherein step b) includes filtering the fumes with at least one filter selected from the group consisting of a charcoal filter, a grease filter, a polysorb filter and an electrostatic precipitator.

29. A module for retrofitting an exhaust hood that exhaust fumes from a food cooking apparatus comprising:

a) a filter; and

b) an ultra-violet lamp joined to the filter, said joined filter and ultra-violet lamp adapted to be mounted within the exhaust hood so that fumes traveling through the exhaust hood are filtered by the filter system and exposed to ultra-violet light from the ultra-violet lamp.

30. The module of claim 29 wherein the ultra-violet lamp provides ultra-violet light having wavelengths in the “C” wavelength range.

31. The module of claim 29 wherein the ultra-violet lamp is a lamp tube.

32. The module of claim 29 wherein the filter includes a grease filter.

33. The module of claim 32 wherein the filter also includes an electrostatic precipitator.

34. The module of claim 29 wherein the filter includes an electrostatic precipitator.

35. The module of claim 29 wherein the filter comprises a grease filter and a charcoal filter.

36. The module of claim 35 wherein filter further comprises an electrostatic precipitator.

37. The module of claim 29 wherein the filter comprises a grease filter and a polysorb filter.

38. The module of claim 37 wherein filter further comprises an electrostatic precipitator.