GB2407153A

GB2407153A - A tray and/or waveguide cap for a forced air/microwave combination oven

Info

Publication number: GB2407153A
Application number: GB0324392A
Authority: GB
Inventors: Stephen Graham Rutherford; James Harold Johns
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-10-18
Filing date: 2003-10-18
Publication date: 2005-04-20
Also published as: WO2005037032A2; WO2005037032A3; GB0324392D0

Abstract

A tray 20 for catching food matter at the bottom of an oven chamber is shaped to cover substantially the entire of the base of the oven chamber (fig 1). The tray may replace a waveguide cap of a forced heated air / microwave combination oven, and may integrally incorporate a waveguide cap 22, upwardly extending edges 24-27, a grille 28 through which forced air is extracted, and support a platter (12, fig 1). Alternatively or in addition, a polymer waveguide cap (figs 4 and 5) is also provided. The tray and the waveguide cap are made of a polymer material, eg a liquid crystal polymer resin such as DuPont (RTM) Zenite (RTM) 7130. This allows cleaning by soaking in water.

Description

24071 53

IMPROVED OVEN COMPONENTS

This invention relates to components for use in ovens. It is particularly applicable, but by no means limited, to components for use in commercial ovens.

Background to the Invention

Forced air / microwave combination ovens are in common usage, and one popular model is the TurboChef C3 oven, supplied by TurboChef Technologies, Inc., of 10500 Metric Drive, Suite 128, Dallas, TX 75243, USA. Such ovens are typically found in petrol stations, motorway service area cafeterias and roadside restaurants, and are used for cooking or defrosting a wide range of foods such as pizzas, hot filled baguettes, lasagne, steak, fish, burgers and pies. The ovens use a combination of rapidly-moving electrically-heated hot air and microwave radiation, and will be referred to herein as forced air / microwave combination ovens. The TurboChef C3 can reach a cooking temperature of 275 C, and cooks on average at seven times the speed of a conventional oven. The microwave generator is located beneath the oven chamber, and transmits microwave radiation via a waveguide up into the oven chamber. The forced air is delivered from above, into the top of the oven chamber, and is extracted through an outlet in the bottom of the chamber, beneath the platter. The air is then passed through a catalytic converter to remove cooking odours, and is recycled within the oven. The microwave and hot air modes of cooking food may be used independently or together, and the oven is processor-controlled to run a range of cooking routines using the different cooking modes.

For cooking or defrosting, food is placed in cookware on the platter inside the oven. The platter is essentially a shelf located towards the bottom of the oven chamber, above the outlet of the microwave waveguide. The platter incorporates holes through which forced air passes, and is also microwave-permeable to enable microwave radiation to reach food placed on the platter.

Beneath the platter, the end of the microwave waveguide is covered by a quartz window, and this is then covered by a waveguide cap which protects the quartz window. Several disadvantages, shortcomings and problems have been identified relating to the base of the oven, the area around the waveguide cap, the waveguide cap itself, and the quartz window, as follows: A forced air / microwave combination oven may be in almost continuous use throughout the day, particularly in motorway service areas and the like which are frequented by customers at all hours. Food can fall through the platter and onto the waveguide cap. Given the nature of the food products that are prepared, the waveguide cap can readily become unclean, particularly from cheese and other molten materials that fall from the cookware and become burnt onto the waveguide cap. In a catering environment, food hygiene and cleanliness are of paramount importance, and so the staff that operate the ovens are required to clean them regularly.

Traditionally, the waveguide cap used in such an oven is made from a porous ceramic material. This chips easily when cleaned, due to the inherent brittleness of the ceramic material. Cleaning staff may not be particularly careful when carrying out their job, and this increases the likelihood of chipping or breakage of the waveguide cap. Also, because of its porosity, a conventional waveguide cap cannot be soaked during cleaning, as this would result in the waveguide cap taking in water through the network of pores inherent in the material. Thus, it will be appreciated that cleaning off the burnt on food products can be very difficult and time consuming to do properly, without soaking the waveguide cap. An unconscientious worker may well soak the waveguide cap, contrary to instructions, or may simply not clean it thoroughly.

Additionally, the quartz window that covers the outlet of the waveguide is fragile and expensive.

Since the platter spans a larger area of the oven than the waveguide cap, food may also fall through the platter onto the base of the oven chamber aside from the waveguide cap. To clean the base of the oven chamber requires the oven to be turned off, during which time it could otherwise be used to prepare food for customers. Also, cleaning the base of the oven chamber requires the cleaning operative to work with their hands and arms inside the oven chamber, which is a confined space and may be hot.

A further problem is that, during use, food may fall into the outlet in the bottom of the chamber through which the hot air is extracted. The traditional approach to overcoming this problem has been to provide a grille (colloquially known as a "pepperoni catcher") over this outlet. However, this grille also may become blocked with food debris. This can impede the airflow within the oven, which is detrimental to the cooking performance of the oven and can also cause the oven to cut out or trip.

Summary of the Invention

According to a first aspect of the invention there is provided a tray for catching food matter, for use at the bottom of an oven chamber, the tray being shaped and configured to cover substantially the entire of the base of the oven chamber in use.

The tray advantageously catches food matter that falls from cookware in the oven during cooking, and thus facilitates the cleaning of the oven. Instead of cleaning the base of the oven itself, a cleaning operative can simply remove the tray, remove any food debris, and clean the tray in an appropriate manner.

Preferably the tray is configured for use in the oven chamber of a forced air / microwave combination oven.

By locating underneath the platter of the forced air / microwave combination oven and covering substantially the entire of the base of the oven chamber in use, the tray advantageously catches food matter that falls through the holes in the platter during cooking.

The tray may be readily removed from the oven for cleaning, thereby facilitating the cleaning process. A dirty tray may be quickly taken out and replaced by a clean tray, thereby enabling a commercial oven to continue being used whilst the dirty tray is being cleaned.

The dirty tray may be cleaned remote from the oven, so that the cleaning operative does not have to perform the cleaning in situ inside the oven.

Preferably the tray integrally incorporates a waveguide cap. This provides the advantage that the tray and waveguide cap may be removed as a single entity for cleaning, should food matter fall onto either the waveguide cap or the tray during cooking.

Preferably the tray further comprises one or more upwardly-extending edge members.

These advantageously assist in the containment of food matter that falls onto the tray during use, and also facilitate lifting the tray out of the oven.

Preferably the tray further incorporates a grille positioned to correspond with the outlet in the oven chamber through which forced air is extracted. This grille enables the traditional "pepperoni catcher" grille to be dispensed with, if desired. Alternatively, this grille may be used in addition to the "pepperoni catcher" grille, thereby providing two barriers to the passage of food matter into the hot air outlet. Since this grill is incorporated in the tray, it is removable with the rest of the tray to facilitate cleaning.

Preferably the grille is integrally formed in the tray by the incorporation of a plurality of apertures defining the grille.

Preferably the grille is situated within an upwardly-extending edge member.

Preferably the tray is made of a polymer material, particularly preferably a liquid crystal polymer resin reinforced with glass, such as DuPont (RTM) Zenite (RTM) 7130.

Advantageously, such materials are tough, easy to clean and may be soaked in water without detriment.

According to a second aspect of the invention there is provided a waveguide cap for use in a forced air / microwave combination oven, made of a polymer material. Replacing a traditional ceramic waveguide cap with a polymer one enables the waveguide cap to be easily cleaned and soaked in water without detriment, and without the risk of brittle fracture associated with ceramic ones.

As well as replacing the ceramic waveguide cap, a polymer one may also be used to replace the traditional quartz window at the end of the waveguide. Highly advantageously, a polymer waveguide cap is inherently less expensive and less fragile than the traditional quartz window.

Preferably the polymer material is a liquid crystal polymer resin reinforced with glass, such as DuPont (RTM) Zenite (RTM) 7130.

Preferably the waveguide cap further comprises a tray member shaped and configured to cover substantially the entire of the base of the oven chamber.

Preferably the tray member further comprises one or more upwardlyextending edge members.

Preferably the tray member further incorporates a grille positioned to correspond with the outlet in the oven chamber through which forced air is extracted.

Preferably the grille is integrally formed in the tray member by the incorporation of a plurality of apertures defining the grille.

Preferably the grille is situated within an upwardly-extending edge member.

According to a third aspect of the invention there is provided an oven having a tray in accordance with the first aspect of the invention.

According to a fourth aspect of the invention there is provided a forced air / microwave combination oven having a waveguide cap in accordance with the second aspect of the invention.

According to a fifth aspect of the invention there is provided a method of cooking using an oven having a tray in accordance with the first aspect of the invention.

According to a sixth aspect of the invention there is provided a method of cooking using a forced air / microwave combination oven having a waveguide cap in accordance with the second aspect of the invention.

Brief Description of the Drawings

Embodiments of the invention will now be described, by way of example, and with reference to the drawings in which: Figure 1 illustrates a traditional forced air / microwave combination oven, indicating the position of the microwave waveguide, waveguide cap and platter in use; Figure 2 illustrates plan and sectional views of an embodiment of a tray shaped and configured to cover substantially the entire of the base of the oven chamber, integrally incorporating a waveguide cap, with example dimensions; Figure 3 illustrates a variant of the embodiment of Figure 2; Figure 4 shows plan and sectional views of an embodiment of a waveguide cap, with example dimensions; and Figure 5 shows plan and sectional views of another embodiment of a waveguide cap, also with example dimensions.

Detailed Description of Preferred Embodiments

The present embodiments represent the best ways known to the applicant of putting the invention into practice. However they are not the only ways in which this can be achieved.

By way of background, Figure 1 shows an example of a TurboChef C3 forced air / microwave combination oven 10. The oven measures approximately 550 mm high, 740 mm wide, and 820 mm from front to back. The microwave waveguide is situated at the base of the oven chamber, and the end of the waveguide is covered by a quartz window 14 using a Teflon (RTM) seal. The quartz window 14 is then covered by a waveguide cap 16. The platter 12 is then located on a pair of support rails 18, above the waveguide cap 16.

The embodiments of the invention that will now be described are presently preferably made from DuPont (RTM) Zenite (RTM) 7130, a microwavepermeable liquid crystal polymer resin reinforced with 30% glass that is able to withstand temperatures of up to 289 C, which is well in excess of the maximum operating temperature of the TurboChef C3 oven. This material is well suited to injection moulding, thereby enabling the intricate shapes of trays and waveguide caps described herein to be readily formed. Highly advantageously, and in marked contrast to traditional porous ceramic components, a resin component can easily be cleaned without risk of brittle failure or chipping, and can be soaked in water without detriment. This enables better hygiene and levels of cleanliness to be maintained.

Other materials suitable for use in a forced air / microwave combination oven may be used instead of DuPont (RTM) Zenite (RTM), and the present disclosure is intended to apply to and encompass all suitable materials already in existence and those which have yet to be discovered or developed, such as advanced engineering polymers, glasses, ceramics and composite materials. For example, DuPont (RTM) Thermx (RTM), a high performance polyester, may be used as an alternative to Zenite (RTM).

Turning now to a first embodiment of the invention, Figure 2 shows a tray 20 moulded to incorporate an integral waveguide cap 22. In use, the tray 20 is placed over the outlet of the waveguide 14 (Figure 1), beneath the platter 12, replacing the traditional waveguide cap 16.

The tray 20 comprises a flat base region 21, from which the integral waveguide cap 22 protrudes. The base region 21 is shaped to occupy substantially the entire of the base of the oven chamber, and is bounded on all four sides by upwardly-extending edge members 24, 25, 26, 27. In use, the base region 21, waveguide cap 22, and edge members 24, 25, 26, 27 catch and retain any food matter that may fall through the apertures in the platter 12. The edge members 24, 25, 26, 27 can also be used to support the platter 12 directly, without the need for the conventional support rails 18 (Figure 1).

The shape of the base region 21, the position and depth of the waveguide cap 22, and the configuration of the upwardly-extending edge members 24, 25, 26, 27 may be altered as necessary to enable the tray 20 to locate over the waveguide outlet, at the bottom of the oven cavity beneath the platter.

The edge member 26 incorporates a grille region 28 shaped and positioned to align with the outlet in the oven cavity through which the forced air is extracted. The grille region 28 is formed as an integral part of the tray 20 by incorporating a plurality of small apertures in the edge member 26. Alternatively, the edge member 26 may be provided with a larger aperture into which a grille insert is located.

The provision of the grill region 28 in the tray 20 enables the conventional "pepperoni catcher" grille to be dispensed with. Alternatively, the grille region 28 may be used in conjunction with the traditional "pepperoni catcher" grille.

The tray 20 may easily be removed from the oven for cleaning. Being made from DuPont (RTM) Zenite (RTM) 7130, the presently preferred embodiment of the tray may be soaked in water during cleaning.

Figure 3 shows an alternative embodiment of the tray of Figure 2, with consistent reference numerals having been used.

Although the trays described above were originally designed for use in a forced air / microwave combination oven, they are also suitable for catching food debris in other types of ovens, including domestic, commercial and industrial ovens (including gas, electric, microwave and combination ovens).

Figure 4 shows a waveguide cap 40 that may be used as a direct replacement for a traditional ceramic waveguide cap (e.g. cap 16 in Figure 1). The waveguide cap 40 incorporates an annular side wall 42 shaped to locate around the end of the microwave waveguide and the quartz window 14 (Figure 1).

The waveguide cap 40 may be used with an optional tray base member (not illustrated) to form an overall assembly of the form shown in Figures 2 and 3.

The waveguide cap 40 may readily be removed from the oven for cleaning. The presently preferred embodiment of the waveguide cap may be soaked in water, by virtue of it being made from DuPont (RTM) Zenite (RTM) 7130.

The waveguide cap 40 may also be used as a replacement for the traditional quartz window 14 (Figure 1). In such a case, the downwardly-extending annular side wall 42 of the waveguide cap 40 may be shaped and configured to locate within the waveguide itself. The side wall 42 of the waveguide cap (and optionally the walls of the waveguide itself) may also be provided with detents, clips or grub screws to fasten the waveguide cap into place.

Figure 5 shows a waveguide cap 50 of an alternative design to that of Figure 4.

As a general principle, two covers are needed at the end of the waveguide: one to prevent matter from falling into the waveguide, and a second (over the first) that can be removed for cleaning. These two covers have traditionally been provided by the quartz window and the ceramic waveguide cap respectively. However, both of these can be replaced using the embodiments described above, e.g. in the following permutations: A waveguide cap 40, 50, as shown in Figure 4 or Figure 5, may be used to replace the traditional quartz window. A tray 20 having an integral waveguide cap, as shown in Figure 2 or Figure 3, may then be located over the waveguide cap 40, 50.

Alternatively, one cap 40, 50 may be used in place of the quartz window, and then another similar but larger waveguide cap 40, 50 may be used over it.

A tray 20 or waveguide cap 40, 50 may be used in conjunction with a traditional quartz window.

A waveguide cap 40, 50 (serving in place of a quartz window) may be used under a traditional ceramic waveguide cap.

Claims

1. A tray for catching food matter, for use at the bottom of an oven chamber, the tray being shaped and configured to cover substantially the entire of the base of the oven chamber in use.

2. A tray as claimed in Claim 1, configured for use in the oven chamber of a forced air / microwave combination oven.

3. A tray as claimed in Claim 2, integrally incorporating a waveguide cap.

4. A tray as claimed in any preceding claim, further comprising one or more upwardly extending edge members.

5. A tray as claimed in Claim 2, Claim 3 or Claim 4 when dependent on Claim 2, further incorporating a grille positioned to correspond with the outlet in the oven chamber through which forced air is extracted.

6. A tray as claimed in Claim 5, wherein the grille is integrally formed in the tray by the incorporation of a plurality of apertures defining the grille.

7. A tray as claimed in Claim 6 or Claim 5 when dependent on Claim 4, wherein the grille is situated within an upwardly-extending edge member.

8. A tray as claimed in any preceding claim, made of a polymer material.

9. A tray as claimed in Claim 8, wherein the polymer material is a liquid crystal polymer resin reinforced with glass.

10. A tray as claimed in Claim 8, made of DuPont (RTM) Zenite (RTM) 7130.

11. A waveguide cap for use in a forced air / microwave combination oven, made of a polymer material.

12. A waveguide cap as claimed in Claim 11, wherein the polymer material is a liquid crystal polymer resin reinforced with glass.

13. A waveguide cap as claimed in Claim 12, made of DuPont (RTM) Zenite (RTM) 7130.

14. A waveguide cap as claimed in any of Claims 11, 12 or 13, further comprising a tray member shaped and configured to cover substantially the entire of the base of the oven chamber.

15. A waveguide cap as claimed in Claim 14, wherein the tray member further comprises one or more upwardly-extending edge members.

16. A waveguide cap as claimed in Claim 14 or Claim 15, wherein the tray member further incorporates a grille positioned to correspond with the outlet in the oven chamber through which forced air is extracted.

17. A waveguide cap as claimed in Claim 16, wherein the grille is integrally formed in the tray member by the incorporation of a plurality of apertures defining the grille.

18. A waveguide cap as claimed in Claim 17 or Claim 16 when dependent on Claim 15, wherein the grille is situated within an upwardly-extending edge member.

19. An oven having a tray as claimed in any of Claims 1 to 10.

19. A forced air / microwave combination oven having a waveguide cap as claimed in any of Claims 11 to 18.

20. A method of cooking using an oven having a tray as claimed in any of Claims 1 to 10.

21. A method of cooking using a forced air / microwave combination oven having a waveguide cap as claimed in any of Claims 11 to 18.

22. A tray for catching food matter substantially as herein described with reference to and as illustrated in any combination of the accompanying drawings.

23. A waveguide cap for use in a forced air / microwave combination oven substantially as herein described with reference to and as illustrated in any combination of the accompanying drawings.

24. A method of cooking substantially as herein described with reference to and as illustrated in any combination of the accompanying drawings.