IE85288B1 - An oven - Google Patents

Abstract

ABSTRACT An oven (1) has a cooking chamber (8) through which food products are delivered on a conveyor (5). Nozzle arrays (9, 10) in the cooling chamber above and below the conveyor (5) direct collimated streams of stream at high velocity at food products on the conveyor (5) for cooking the food products. Each nozzle array (9, 10) is mounted on a manifold (1 1, 12). Closure plates (17, 18) mounted at the inlet of each manifold are operable to regulate the flow of stream within the manifold (11, 12). A heater assembly (30) is provided indirect heating of steam in a steam supply duct connected to the manifolds (1 1, 12).

Description

Introduction This invention relates to ovens, in particular for the cooking of food products on a commercial scale.

Statements of Invention According to the invention there is provided an oven having an inlet and an outlet; a food transport conveyor extending through the oven between the inlet and the outlet; conveyor drive means which is operable to move the conveyor between the inlet and the outlet; a cooking chamber within the oven; said conveyor passing through said cooking chamber; a pair of spaced-apart nozzle arrays, namely an upper nozzle array mounted above the conveyor and a lower nozzle array mounted below the conveyor, each nozzle array is operable for directing a collimated stream of steam at high velocity towards the conveyor for cooking food products on the conveyor; each nozzle array being mounted on a manifold; a steam supply duct for delivery of steam from a steam supply source to an inlet of each manifold; steam flow regulating means at the inlet of each manifold; said steam flow regulating means comprising a plurality of spaced—apart steam inlet slots at the inlet of the manifold and a complementary slotted closure plate which is movable between an open position opening the steam inlet slots, through an intermediate position partially closing the steam inlet slots, and a closed position closing the steam inlet slots.

In one embodiment of the invention the slotted closure plate is slidably mounted at the inlet of the manifold for movement between the open position and the closed position.

In another embodiment of the invention a drive shaft is attached to the slotted closure plate, the drive shaft being slidably mounted on a support, a rack mounted on the drive shaft, said rack engaged by a drive gear, and means for rotation of the drive gear for sliding movement of the drive shaft and the slotted closure plate.

In a further embodiment of the invention locking means is provided for releasably locking the drive shaft. in another embodiment of the invention a heater is mounted in the steam supply duct, said heater comprising a coiled tube having an inlet and an outlet, the inlet _ 3 _ being connected to a fuel burner for delivery of combustion gases through the coil for heating steam delivered through the duct.

In another embodiment of the invention the outlet of the coiled tube is connected to an extraction fan for drawing the combustion gases through the coiled tube in a controlled manner.

Detailed Description of the Invention The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is an elevational view illustrating an oven according to the invention; Fig. 2 is a plan view of the oven; Fig. 3 is an end elevational view of the oven; Fig. 4 is another end elevational view of the oven from the opposite end to that shown in Fig. 3; Fig. 5 is a detail elevational view showing a steam flow regulator forming portion of the oven; Fig. 6 is a plan view of the steam flow regulator; Fig. 7 is an end elevational view of the steam flow regulator; Fig. 8 is an elevational view of another steam flow regulator forming portion of the oven; Fig. 9 is a plan view of the steam flow regulator of Fig. 8; Fig. 10 is an end elevational view of the steam flow regulator of Fig. 8; Fig. 11 is an elevational view of a heater assembly forming portion of the oven; Fig. 12 is a plan view of the heater assembly; and Fig. 13 is an end elevational view of the heater assembly.

Referring to the drawings, there is illustrated an oven according to the invention indicated generally by the reference numeral 1. The oven 1 has a housing 2 with an inlet 3 and an outlet 4. A food transport conveyor 5 comprising an endless mesh belt supported on rollers (not shown) extends through the oven 1 between the inlet 3 and the outlet 4. A drive roller 6 is connected to a drive motor for moving the conveyor 5 around the support rollers in a direction between the inlet 3 and outlet 4 for feeding food products mounted on the conveyor 5 between said inlet 3 and outlet 4.

A cooking chamber 8 is provided within the housing 2, the conveyor 5 passing through the cooking chamber 8. A pair of spaced-apart nozzle arrays, namely an upper nozzle array 9 and a lower nozzle array 10 are mounted above and below respectively the conveyor 5. Each nozzle array 9, 10 has a plurality of nozzles, extending across the width of the conveyor 5, for directing a collimated stream of steam at high velocity towards the conveyor 5 for cooking food products on the conveyor 5.

Each nozzle array 9, 10 is mounted on an associated manifold 11, 12 respectively. A steam supply duct 15 is connected to an inlet of each manifold 11, 12 for delivery of steam to each manifold 11, 12 for discharge through the nozzles. For regulating the delivery of steam to each manifold 11,1 12 slotted closure plates 17, 18 are mounted at an inlet of each manifold 11, 12 for complementary cooperation with associated steam inlet slots at the inlet of each manifold 11, 12.

Figs. 5 to 7 show the upper closure plate 17 in more detail. The nlngum nlatn 30 comprises a rectangular plate with a number of spaced-apart openings 20. These correspond to a similar complementary set of spaced-apart slots at the inlet to the manifold 11 . A drive shaft 21 connected to one end of the closure plate 17 is slidably mounted on a support within a housing 22. A rack 23 is mounted on the drive shaft 21 within the housing 22. A drive gear 24 engages associated gear teeth on the rack 23. The drive gear 24 is mounted on a spindle 25 which is rotatably supported in the housing 22 and extends outwardly of the housing 22 terminating in a handle 26.

Rotation of the handle 26 turns the drive gear 24 which in turn causes lateral movement of the drive shaft 21 for sliding the closure plate 17 back and forth to either close off the inlet slots at the manifold 11 or align the openings 20 with the inlet slots to allow through-passage of steam into the manifold 11. Thus steam inlet to the manifold 11 can be regulated.

Figs. 8 to 10 show the lower closure plate 18. this is essentially similar to the upper closure plate 17 and like parts are assigned the same reference numerals. Operation is also the same, the sliding of the lower closure plate 18 regulating steam flow through the inlet slots in the lower manifold 12.

A locking bolt 27 mounted on the housing 22 is operable to releasably engage and lock the drive shaft 21 on the housing 22.

A heater assembly 30 is operable for heating steam within the steam supply duct 15 to a desired temperature prior to delivery to the manifolds 11, 12. The heater assembly 30 is shown in more detail in Figs. 11 to 13. The heater assembly 30 comprises a coiled tube 32 which is mounted within the steam supply duct 15. The coiled tube 32 has an inlet 33 which connects to a burner assembly 34. A fuel such as gas is supplied to the burner assembly 34 and combustion gases are then delivered through the coiled tube 32 for indirect heat transfer to steam passing through the steam supply duct 15. An outlet 35 of the coiled tube 32 is connected through an exhaust pipe 36 with an extractor fan 37 driven by electric motor 38 for drawing combustion gases through the coiled tube 32 in a controlled manner.

In use, food products are delivered onto the conveyor 5 at the inlet 3 of the oven 1 for delivery through the oven 1. As the fnnd nrndiinte nae: thrnunh Hm nnnl/inn nkamkny , high speed streams of steam are directed towards the food products carried on the conveyor 5 for cooking the food products. The closure plates 17, 18 at the inlet of each manifold 11, 12 can be adjusted to regulate the supply of steam to the nozzles mounted on the manifolds 11, 12. Steam delivered into the steam supply manifold 15 is heated in a controlled manner by the heating apparatus 30 to the required cooking temperature.

It will be appreciated that the adjustment of the closure plates 17, 18 on the manifolds 11, 12 allows individual control and fine adjustment of'the steam delivery to each nozzle array. Also, with regard to the heater, gas or thermal oil can be used to provide the heat. The indirect heating of the steam by the heater assembly 30 is advantageous in that there is no mixing of combustion gases with steam which would adversely affect the quality of the product. It is also safer and easier to manage than a direct heating system. Drawing the combustion gases through the coiled tube 32 by means of the extractor fan gives better heat distribution and efficiency.

It will be appreciated that while the closure plates 17, 18 may be manually operable as illustrated in the drawings, control means may be provided for sliding movement of the closure plates 17, 18, for example rams could be provided for sliding movement of the drive shaft connected to the closure plates 17, 18.

The invention is not limited to the embodiments hereinbefore described but may be varied in both construction and detail.

Claims (1)

1. CLAIMS An oven having an inlet and an outlet; a food transport conveyor extending through the oven between the inlet and the outlet; conveyor drive means which is operable to move the conveyor between the inlet and the outlet; a cooking chamber within the oven; said conveyor passing through said cooking chamber; a pair of spaced—apart nozzle arrays, namely an upper nozzle array mounted above the conveyor and a lower nozzle array mounted below the conveyor, each nozzle array is operable for directing a collimated stream of steam at high velocity towards the conveyor for cooking food products on the conveyor; each nozzle array being mounted on a manifold; a steam supply duct for delivery of steam from a steam supply source to an inlet of each manifold; steam flow regulating means at the inlet of each manifold; said steam flow regulating means comprising a plurality of spaced—apart steam inlet slots at the inlet of the manifold and a complementary slotted closure plate which is movable between an open position opening the steam inlet slots, through an intermediate position partially closing the steam inlet slots, and a closed position closing the steam inlet slots. An oven as claimed in claim 1 wherein the slotted closure plate is slidably mounted at the inlet of the manifold for movement between the open position and the closed position. An oven as claimed in claim 2 wherein a drive shaft is attached to the slotted closure plate, the drive shaft being slidably mounted on a support, a rack mounted on the drive shaft, said rack engaged by a drive gear, and means for rotation of the drive gear for sliding movement of the drive shaft and the slotted closure plate. An oven as claimed in claim 3 wherein locking means is provided for releasably locking the drive shaft. An oven as claimed in any preceding claim wherein a heater is mounted in the steam supply duct, said heater comprising a coiled tube having an inlet and an outlet, the inlet being connected to a fuel burner for delivery of combustion gases through the coil for heating steam delivered through the duct. An oven as claimed in claim 5 wherein the outlet of the coiled tube is connected to an extraction fan for drawing the combustion gases through the coiled tube in a controlled manner.