GB2059571A

GB2059571A - Heating chamber

Info

Publication number: GB2059571A
Application number: GB8030762A
Authority: GB
Original assignee: BP PLC
Current assignee: BP PLC
Priority date: 1979-09-28
Filing date: 1980-09-24
Publication date: 1981-04-23

Abstract

A chamber adapted to be heated by a fluid, preferably steam, comprises top, bottom, back and side walls and a door. The top, bottom and side walls contain heating coils (8, 9) in contact with the walls and are surrounded by thermally insulating material (10). The heating coils are embedded in cement. The chamber is suitable for use as an oven for heating food rapidly in hazardous locations. <IMAGE>

Description

SPECIFICATION Heating chamber This invention relates to a chamber heated by heating coils and in particular to a steam heated oven.

Oil refinery processing units, petrochemical plants and the like are operated on a continuous basis and manned by operators working on shifts.

Inevitably this gives rise to catering problems since shift workers require meals during the night and at other times when normal catering facilities are not available.

Numerous attempts to solve this problem have been made. The simplest is to provide packed meals of the picnic variety but these are not very satisfactory and hot meals are more appreciated by the workers. With the advent of deep frozen foodstuffs it is now possible to provide hot meals quickly without requiring cooking skill but these require to be heated on site, for example, in rest rooms. Rest rooms are frequently associated with control rooms on process units and therefore are in hazardous areas where conventional cooking equipment such as electric or gas cookers or microwave ovens cannot be used. Flame proof electric hot plates are available but these are expensive and do not heat frozen foods quickly enough thus giving rise to health hazards.

Frozen food must be heated quickly since the temperature range of 1000 -2000F (380 to 930C) is particularly suitable for bacterial growth.

If the temperature rises slowly through this range any contaminating bacteria present will multiply rapidly and may not all be destroyed when higher temperatures are reached.

We have now devised a simple heated chamber which supplies dry heat by convection and radiation to substances placed within it.

Thus according to the present invention there is provided a chamber adapted to be heated by a fluid, preferably steam, which chamber comprises top, bottom, back and side walls and a door, the top, bottom and side walls being hollow and containing heating coils in contact with the walls and being surrounded by insulating material.

Preferably each side wall has an individual heating coil and a third coil for supplying heat to the top, back and bottom walls.

Preferably contact between the walls and the heating coils is achieved by embedding the latter in thermal cement to ensure efficient heat transfer to the interior walls of the chamber.

Alternatively, the coils may be spot welded to the walls.

Conventional constructional materials may be used, for example stainless steel sheeting for the walls of the chamber, copper tubing or stainless steel for the heating coils and the material sold under the trade name Rockwool for the insulation.

When the chamber is used as an oven in a process unit rest room high pressure process steam will be available and this is a very suitable heating medium.

When process steam is used the outlets from the steam coils should lead into a manifold containing a steam trap.

The invention is illustrated with reference to Figs. 1, 2, 3 and 4 of the accompanying drawings wherein Fig. 1 is an elevation of an oven according to the present invention, Fig. 2 is a section on BB of Fig. 1 excluding the door, Fig. 3 is a sectional plan on AA of Fig. 1, excluding the door and Fig. 4 is a detail showing the door.

With reference to the drawings: The oven comprises a door 1, side walls 2 and 3, a top 4, a back 5 and a bottom 6. All are fabricated from stainless steel sheet and all are hollow. Side walls 2 and 3 each contain steam coils 7 and 8. A single steam coil 9 passes through top 4, back 5 and bottom 6. The steam coils 7, and 9 are fabricated from copper tubing and are embedded in "Thermon" heat transfer cement, a cement containing carbon particles. The cavity of the door 1 is filled with Rockwool insulation. The sides 2, 3 the top 4, the back 5 and the bottom 6 are also surrounded by an outer cavity 10 containing Rockwool. The door is pivotted on hinges 1, and maintained in position by a catch 12.

High pressure process steam is continuously supplied to the heating coils at a pressure of 1 70 psig (11.7 bars) and a temperature about 4000F (2500C). This is sufficient to maintain a temperature in the oven of about 350"F (1800 C).

Since the heating coils surround the oven, apart from the door, heat is supplied from top, bottom and sides and the temperature within the oven is uniform. The heat is maintained by both convection and radiation within the oven.

Since the oven is continuously maintained at a high temperature, food placed within it is rapidly brought up to temperature and passes quickly through the dangerous zone of 1000 -2000F (380 to 930C). In general, deep frozen food will be ready for eating after about 25 minutes in the oven.

The oven has no electrical contacts and no flame and therefore is inherently safe for use in a hazardous environment. It is ruggedly simple in construction and reliable in operation.

1. A chamber adapted to be heated by a fluid which chamber comprises top, bottom, back and side walls and a door, the top, bottom and side walls being hollow and containing heating coils in contact with the walls and being surrounded by insulating material.

2. A chamber according to claim 1 wherein each side wall has an individual heating coil and a third coil for supplying heat to the top, back and bottom walls.

3. A chamber according to either of the preceding claims wherein contact between the walls and the heating coils is achieved by

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Heating chamber This invention relates to a chamber heated by heating coils and in particular to a steam heated oven. Oil refinery processing units, petrochemical plants and the like are operated on a continuous basis and manned by operators working on shifts. Inevitably this gives rise to catering problems since shift workers require meals during the night and at other times when normal catering facilities are not available. Numerous attempts to solve this problem have been made. The simplest is to provide packed meals of the picnic variety but these are not very satisfactory and hot meals are more appreciated by the workers. With the advent of deep frozen foodstuffs it is now possible to provide hot meals quickly without requiring cooking skill but these require to be heated on site, for example, in rest rooms. Rest rooms are frequently associated with control rooms on process units and therefore are in hazardous areas where conventional cooking equipment such as electric or gas cookers or microwave ovens cannot be used. Flame proof electric hot plates are available but these are expensive and do not heat frozen foods quickly enough thus giving rise to health hazards. Frozen food must be heated quickly since the temperature range of 1000 -2000F (380 to 930C) is particularly suitable for bacterial growth. If the temperature rises slowly through this range any contaminating bacteria present will multiply rapidly and may not all be destroyed when higher temperatures are reached. We have now devised a simple heated chamber which supplies dry heat by convection and radiation to substances placed within it. Thus according to the present invention there is provided a chamber adapted to be heated by a fluid, preferably steam, which chamber comprises top, bottom, back and side walls and a door, the top, bottom and side walls being hollow and containing heating coils in contact with the walls and being surrounded by insulating material. Preferably each side wall has an individual heating coil and a third coil for supplying heat to the top, back and bottom walls. Preferably contact between the walls and the heating coils is achieved by embedding the latter in thermal cement to ensure efficient heat transfer to the interior walls of the chamber. Alternatively, the coils may be spot welded to the walls. Conventional constructional materials may be used, for example stainless steel sheeting for the walls of the chamber, copper tubing or stainless steel for the heating coils and the material sold under the trade name Rockwool for the insulation. When the chamber is used as an oven in a process unit rest room high pressure process steam will be available and this is a very suitable heating medium. When process steam is used the outlets from the steam coils should lead into a manifold containing a steam trap. The invention is illustrated with reference to Figs. 1, 2, 3 and 4 of the accompanying drawings wherein Fig. 1 is an elevation of an oven according to the present invention, Fig. 2 is a section on BB of Fig. 1 excluding the door, Fig. 3 is a sectional plan on AA of Fig. 1, excluding the door and Fig. 4 is a detail showing the door. With reference to the drawings: The oven comprises a door 1, side walls 2 and 3, a top 4, a back 5 and a bottom 6. All are fabricated from stainless steel sheet and all are hollow. Side walls 2 and 3 each contain steam coils 7 and 8. A single steam coil 9 passes through top 4, back 5 and bottom 6. The steam coils 7, and 9 are fabricated from copper tubing and are embedded in "Thermon" heat transfer cement, a cement containing carbon particles. The cavity of the door 1 is filled with Rockwool insulation. The sides 2, 3 the top 4, the back 5 and the bottom 6 are also surrounded by an outer cavity 10 containing Rockwool. The door is pivotted on hinges 1, and maintained in position by a catch 12. High pressure process steam is continuously supplied to the heating coils at a pressure of 1 70 psig (11.7 bars) and a temperature about 4000F (2500C). This is sufficient to maintain a temperature in the oven of about 350"F (1800 C). Since the heating coils surround the oven, apart from the door, heat is supplied from top, bottom and sides and the temperature within the oven is uniform. The heat is maintained by both convection and radiation within the oven. Since the oven is continuously maintained at a high temperature, food placed within it is rapidly brought up to temperature and passes quickly through the dangerous zone of 1000 -2000F (380 to 930C). In general, deep frozen food will be ready for eating after about 25 minutes in the oven. The oven has no electrical contacts and no flame and therefore is inherently safe for use in a hazardous environment. It is ruggedly simple in construction and reliable in operation. CLAIMS

3. A chamber according to either of the preceding claims wherein contact between the walls and the heating coils is achieved by embedding the latter in thermal cement.

4. A chamber according to any of the preceding claims wherein the heating fluid is high pressure process steam.

5. A chamber as hereinbefore described with reference to the accompanying drawings.