Gas combination oven

• US 4,817,582 A
• Filed: 09/17/1987
• Issued: 04/04/1989
• Est. Priority Date: 09/17/1987
• Status: Expired due to Term

• Current Assignee: Groen, Inc.
• Original Assignee: Delaware Capital Formation Incorporated (Dover Corporation)
• Inventors: Jepson, Stewart C., Oslin, G. Robert
• Primary Examiner(s): Scott, Samuel
• Assistant Examiner(s): Kamen, Noah
• Application Number:
  US07/097,842
• Time in Patent Office: 565 Days
• Field of Search: 126/20, 126/19 R, 126/21 A, 126/39 R, 126/39 C, 126/39 D, 126/39 E, 126/39 F, 126/91 A, 126/273 R, 126/348, 126/369, 219/401, 99/474, 99/415, 99/418, 99/330, 99/359, 432/209, 34/197, 34/198, 122/17
• US Class Current: 126/21.00A
• CPC Class Codes: A21B 1/24 Ovens heated by media flowing therethrough
• CPC Class Codes: A21B 1/40 characterised by the means for regulating the temperature
• CPC Class Codes: A21B 3/04 Air-treatment devices for ovens, e.g. regulating humidity
• CPC Class Codes: F24C 15/322 with forced circulation

Abstract

A gas-fired combination steam and dry oven has an oven cavity that is heated by heat exchange from one or more fire tubes and a boiler that is located outside the oven cavity and is heated by heat exchange from one or more other fire tubes. Both the oven and boiler fire tube heat exchangers employ natural draft gas burners. The combination oven can be operated as a forced-air convection oven, a forced-flow convection oven circulating superheated steam, or a steamer circulating saturated steam. Sensors in the oven supply information to a microprocessor that controls the gas burners to maintain an oven temperature within 5° F. or less. Sensors of the level of water in the boiler assure that the water level stays within predetermined limits. Tray stops keep foods and the trays containing them away from the walls of the oven to permit free circulation of air, saturated steam, or superheated steam. Sensors of water temperature in the boiler and of the circulating mixture of air and water vapor temperature in the oven chamber permit the control of relative humidity when the oven is used to proof dough or hold cooked food at a relatively low temperature. Control of the temperature of water in the boiler is aided by blowdown and replacement if the water temperature becomes too high.

Claims

1. A combination cooking oven that is heated by gas comprising:

an enclosure;

an oven inner chamber in said enclosure that is substantially a rectangular parallelpiped defined by a top plate, a bottom plate, a side wall that includes a plurality of apertures, a fan shroud, a rear wall and a front wall that includes a door, the shroud spaced from the enclosure to form a plenum, the top plate, bottom plate and side wall spaced from the enclosure to form with the rear wall and the front wall a heat-exchange region;

a plurality of fire tubes disposed in the heat-exchange region;

a plurality of gas burners disposed to heat the fire tubes by passing hot combustion products through the fire tubes, and a second and third gas burner heating another of said serpentine compartments;

a fan disposed in the shroud to circulate gases and vapors through the oven inner chamber, the heat-exchange region and back to the oven inner chamber through the apertures in the side wall;

means for supplying steam to the oven inner chamber comprising a boiler having a plurality of gas burners disposed to send hot combustion products through a vertical array of serpentine channels in a fire tube within a chamber having a water inlet and a steam outlet, wherein at least one channel is heated by two burners;

mean for sensing temperatures in the oven inner chamber and in the means for supplying steam; and

means responsive to the means for sensing temperatures for controlling the oven in heated air, steam and combination cooking modes.

2. The combination cooking oven of claim 1 wherein the plenum, top plate, bottom plate and side plate are removable without the use of tools

3. The combination cooking oven of claim 1 wherein the means for supplying steam further comprises:

means for draining the boiler.

4. The combination cooking oven of claim 3 wherein the boiler fire tube is a double-pass fire tube.

5. The combination cooking oven of claim 1 wherein the means for controlling the oven comprises a microprocessor coupled to the means for sensing temperature, the microprocessor adapted to receive control inputs and produce output signals to control operation of the oven.

6. The combination cooking oven of claim 5 consisting in addition:

means for sensing a level of water in the boiler;

means for connecting the means for sensing to the microprocessor; and

means connected to the microprocessor for controlling the level of water in the boiler according to predetermined criteria.

7. The combination cooking oven of claim 1 wherein the side wall is disposed parallel to and opposite the fan shroud so that air flow in the oven inner chamber is substantially unidirectional from the fan to and through the side wall.

8. The combination cooking oven of claim 1 wherein the side wall is disposed parallel to and opposite the fan shroud so that air flow in the oven inner chamber is substantially unidirectional from the side wall to the fan.

9. The combination cooking oven of claim 1 wherein the apertures are distributed uniformly in the side wall.

10. The combination cooking oven of claim 1 wherein the apertures are distributed in the side wall in a predetermined pattern to direct air flow in the inner chamber in substantially uniform flow.

11. The combination cooking oven of claim 1 wherein the fire tubes are vented to the atmosphere without passing combustion products through the oven inner chamber.

12. A boiler for producing steam for cooking food comprising:

a plurality of gas burners;

means for igniting gas to produce hot combustion products;

a plurality of serpentine channels in a fire tube and disposed in a boiler chamber;

at least one channel heated by one gas burner, and a plurality of channel each heated by two gas burners;

means for admitting water to the boiler chamber in a heat-exchange relationship with the boiler fire tube to heat the water and produce steam within the boiler chamber; and

means for conveying the steam from the boiler chamber to the oven.

13. The boiler of claim 12 comprising in addition means for sensing temperature of the water;

and

means for controlling a flow of gas to the burner in response to the sensed temperature to maintain a predetermined temperature.

14. The boiler of claim 12 wherein the gas burners are in a stacked vertical array.

15. The boiler of claim 14 wherein the boiler has a smallest dimension that is horizontal.

16. A gas-heated cooking oven comprising:

an enclosure;

an oven inner chamber that is substantially a rectangular parallelpiped defined by a top plate, a bottom plate, a side wall that includes a plurality of apertures, a fan shroud, a rear wall and a front wall that includes a door, the shroud spaced from the enclosure to form a plenum, the top plate, bottom plate and side wall spaced from the enclosure to form a heat-exchange region with the rear wall and the front wall;

a plurality of fire tubes disposed substantially parallel to each other in the heat-exchange region;

a plurality of gas burners disposed to heat the fire tubes by natural draft by passing hot combustion products through the fire tubes;

a fan disposed in the shroud to circulate gases and vapors through the oven inner chamber, the heat-exchange region and back to the oven inner chamber through the apertures in the side wall, the circulation producing partially concurrent and partially countercurrent heat exchange;

a boiler having a double-pass fire tube that passes combustion products in a serpentine arrangement of two passes;

a gas burner disposed to heat the boiler fire tube by natural draft;

means for admitting water to the boiler;

means for draining the boiler; and

means coupled to the oven inner chamber for conveying steam to the oven inner chamber.

17. A gas-heated cooking oven comprising:

an inner chamber for cooling food; and

outer chamber encompassing top bottom, and sides of the inner chamber and forming therebetween a heat exchange region;

a plurality of fire tubes disposed substantially parallel to each other within the adjacent the bottom, a side, and top of the inner chamber and exhausting to the atmosphere;

a plurality of gas burners for heating the fire tubes by natural draft by passing hot combustion products through the fire tubes and exhausting the combustion products to the atmosphere;

a fan disposed adjacent a side opposite the side which the tubes are adjacent the tubes are adjacent so as to circulate gases and vapors through the oven inner chamber, the heat-exchange region and back to the oven inner chamber through apertures in side wall, the circulation producing partially concurrent and partially countercurrent heat exchange;

means for supplying superheated steam to the oven inner chamber;

means for sensing temperatures in the oven inner chamber and in the means for supplying superheated steam; and

means responsive to the means for sensing temperatures for controlling the oven in each of the heated air, steam, and combination cooking modes.