GB2206026A - Searing machine for food product - Google Patents

Abstract

A searing machine for a food product such as a sausage comprises a conveyor device 19 operable to move the sausages 24 along a path past heating stations 50, 51. Each heating station comprises an infrared heat source disposed within a reflector which is operable to focus heat into a narrow band on the food product as it is carried past the heating station. Cooling surfaces 65 are provided for simultaneously cooling the food product to prevent overheating. The precisely-focussed reflectors apply a clearly-defined sear line to the product. <IMAGE>

Description

SEARING MACHINE FOR FOOD PRODUCT This invention relates to an apparatus and method for applying a sear mark to a food product such as a sausage.

Certain kinds of goods product are traditionally cooked over a direct heat source such as charcoal or a wood fire. One such example is the German bratwurst sausage, which is usually purchased ready cooked. Bratwurst is typified not only by its particular flavour, but also by the fact that it is usually cooked on a charcoal grill which leaves characteristic sear marks along the length of the sausage. These sear marks are attractive in appearance and make the bratwurst readily distinguishable from other pre-cooked sausages.

Modern methods of sausage production are able to produce bratwurst with the same flavour as traditional sausages, but cooking methods using charcoal grills are not suitable for quantity production, and these mass-produced bratwurst have not been marked with the characteristic sear lines along the sausage. Arrangements using heated rollers have been used but these do not produce consistent results with even searing of the product.

This invention provides a searing machine for applying sear marks to sausages and other food products which can operate at the speeds required for quantity production.

According to the present invention, there is provided a searing machine for a food product comprising conveyor means for conveying a food product along a path; heating means located adjacent said path and comprising an infra-red heat source disposed within a reflector, said reflector being adapted to focus heat from the heat source onto the food product carried by said conveyor means; and cooling means disposed adjacent said path operable to cool the food product during the heat treatment; whereby said heating means is operable to apply a clearly-defined sear line to the outer surface of the food product during movement thereof along said path.

The use of a radiant heat source which is focussed precisely onto the outer surface of the food product enables the product to be treated whilst moving through the machine, and this overcomes the disadvantages of slow throughput associated with searing devices which operate whilst the food product is stationary. Speed control means may be provided for the conveyor which enables the intensity of the sear line to be varied.

The machine is particularly suitable for treating sausages, and preferably is adapted to convey a sausage along a path substantially co-axially with its longitudinal axis; advantageously the conveyor means comprises the upper run of a chain conveyor, which may consist of a pair of parallel chains spaced such that a sausage can be supported therebetween.

Suitably, the infra-red heat source may comprise an elongate heating element extending substantially parallel to said chain conveyor, said reflector being adapted to focus radiant heat from said element into a narrow band on a sausage or other food product supported on the conveyor.

In one embodiment the heating means may be provided with a shield adapted to prevent fat from the food product contacting the heating element, said shield comprising an aperture in the form of a narrow slot through which the radiant heat is focused.

The invention also comprehends a method of applying a sear mark to a food product, comprising conveying said food product past a heating station at which infra-red radiant heat is focused into a narrow band on the food product; and simultaneously cooling the food product to prevent burning thereof.

In order that the invention may be more fully understood, an embodiment in accordance therewith will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a side elevation of a sausage searing machine; Figure 2 shows an end elevation of the sausage searing machine shown in Figure 1, looking in the direction of arrow II therein; and Figure 3 is a plan view of the sausage searing machine show in Figures 1 and 2, with some parts omitted for clarity.

Referring to the drawings, apparatus for applying a sear mark to a sausage comprises a support table generally indicated at 10 formed from longitudinal members 11 and legs 12. Table 10 has a top surface 15 carrying most of the working features of the apparatus, as will be described.

Hinged to the top surace 15 of table 10 is a lid 16 which can be opened to expose the working parts of the apparatus. This is suitably provided with an air damping cylinder (not shown) to facilitate opening and the closing.

The apparatus shown in the drawings is intended for searing two lines of sausages simultaneously, and the conveying system for carrying sausages through the apparatus comprises, for each line, a chain conveyor 19 comprising a pair of parallel small pitch stainless steel transport chains 20 and 21. As will be seen from Figure 3, the sausages 24 are supported between the respective transport chains 20, 21, the upper runs of these chains defining the path of movement of the sausages through the apparatus. The substantially horizontal upper runs of the chains are supported on pulleys 26, 27, 28 and 29. It will be seen from Figure 1 that in this embodiment, for ease of constuction the upper runs of the chains 20, 21 are split at a point substantially mid-way along the conveyor run into a first section 30 and a second section 31.

Each chain conveyor 19 is provided with a drive sprocket 33, 34 which is connected by a gearbox 37 to a variable speed drive 38. The conveyor is driven at a speed of between 2 and 6 m/min. depending on the degree of heat to be applied to the sausages 24 during transit through the apparatus.

Sausages are fed onto each chain conveyor 19 by means of a respective delivery chute 40 comprising an inclined ramp terminating at the begining of the conveyor run. Sausages may be loaded onto the chutes 40 either automatically or by hand.

The heating devices for applying the sear line to the sausages comprise, for each chain conveyor 19, a first pair of infra-red heaters 50, 51 arranged on one side of the conveyor run, and a second pair of infra-red heaters 52, 53 arranged on the other side of the conveyor run. Each infra-red heater comprises a water-cooled casing 55, a two-dimensional elliptical reflector 56, and an infra-red tungsten filament 57 inside a quartz envelope. Each casing 55 is provided with ports 60, 61 for inflow and outflow of cooling water. It is essential to cool the heaters as the filament operates at 0 approximately 2,200 C. The lamps are mounted on the upper surface 15 of table 10 by means of supports 62 and brackets 63 which allow a degree of adjustment towards and away from the conveyor 19. The distance between the filaments and the sausages is suitably between 40 and 80 mm, and preferably around 60mm. Each lamp is rated at 2KW and produces a 0 temperature of around 200 C on the surface of the sausage.

If required a gas supply can be provided for cooling the lamp filaments.

The reflectors are designed to focus the heat from the filaments into a focal line approx 2.5 mm wide. This provides a concentrated line of heat which burns a sear mark into the sausage skin.

In order to prevent overheating of the sausages as they pass the lamps 50, 51 and 52, 53, a cooling surface is disposed opposite the lamps on the other side of the conveyor run. In the case of lamps 50, 51 this cooling surface is denoted at 65. In the case of lamps 52, 53 this cooling surface is denoted at 66. These surfaces comprise one side of enclosures 67, 68, 69, 70 which are supplied with a constant flow of cooling water via ports 75. A flow control valve (not shown) is provided to control the flow of cooling water through the enclosures and hence the degree of cooling for the product.

An interlock switch may be fitted to prevent operation of the heating apparatus when this water flow valve is closed.

In order to prevent fat given off by the products soiling the infra-red filaments 57 during the searing operation, lamp shields 70 may be fitted over the reflectors 56, as shown on the left-hand side of Figure 2. Each lamp shield comprises a nozzle-like enclosure disposed over the reflector and provided with a narrow opening 71 through which the heat is focused.

The sheild substantially reduces contamination of the filaments during operation and enables the apparatus to be run for longer periods without cleaning.

In operation, sausages 24 to be treated in the apparatus are fed down the delivery chutes 40 and fall onto the upper surface of the respective chain conveyor which carries them at a controlled rate past heaters 50, Sf and 52, 53. The reflectors concentrate the heat along a narrow focal line, and the heaters 50, 51 apply a single sear line to one side of the sausage, whereas heaters 52, 53 apply a similar sear line to the other side of the sausage. The opposite sear lines provide the bratwurst sausage with its characteristic appearance. The apparatus is cooled continuously during operation to avoid overheating, and the cooling surfaces disposed opposite the heaters prevent the sausages burning in the apparatus. Cooling air may also be blown through the apparatus, and a hood extractor may be provided to remove this air together with the cooking fumes.

The sausages 24 enter and exit the apparatus through tunnels 80, 81 which provide protection for the operators from the glare of the infra-red heating lamps and which also provide a thermal barrier for safety purposes. At the end of the apparatus the sausages drop from the conveyor into a suitable container.

The lid 16 which encloses the apparatus during operation is connected to the power supplies for the infra-red lamps and the chain conveyor drive so that the machine is automatically switched off when the lid is raised. A secondary safety cover 18 is also hinged to the upper surface 15 of the table 10 and this comprises a mesh enclosure which prevents access to the hot parts of the apparatus until these have cooled. This can be achieved by a time delay mechanism or by a thermal cut-out which releases the catch for the cover when the temperature has fallen to a safe level.

While the apparatus shown is intended for sausages, it will be appreciated that other food products can be treated equally well, if necessary with some adaptation of the conveyor. If additional heating is required, it is a simple matter to add further heating and cooling sections to the apparatus.

Claims (8)

CLAIMS:

1. A searing machine for applying a sear mark to a food product, comprising conveyor means for conveying a'food product along a path; heating means located adjacent said path and comprising an infra-red heat source disposed within a reflector, said reflector being operable to focus heat from the heat source to a narrow band on a food product carried by said conveyor means; and cooling means operable to cool the food product during its heat treatment; whereby said heating means is operable to apply a clearly-defined sear line to the outer surface of the food product during movement thereof along said path.

2. A searing machine as claimed in Claim 1, wherein said conveyor means comprises a chain conveyor having a pair of parallel chains spaced such that said food product can be supported therebetween.

3. A searing machine as claimed in Claim 1 or Claim 2, wherein the infra-red heat source comprises an elongate heating element extending substantially parallel to said path; and said reflector is operable to focus radiant heat from said element into a narrow band.

4. A searing machine as claimed in Claim 3, wherein said heating means is provided with a shield device adapted to prevent fat contacting said heating element, said shield device comprising an aperture in the form of a narrow slot through which the radiant heat is focussed.

5. A searing machine as claimed in any preceding claim, wherein the food product is a sausage and said conveyor means is adapted to convey the sausage along a path substantially co-axial with the longitudinal axis of the sausage.

6. A searing machine, substantially as hereinbefore described with reference to the accompanying drawings.

7. A method of applying a sear line to a food product, comprising conveying said food product at a controlled speed past a heating station comprising an infra-red heat source disposed within a reflector; focussing heat from said heat source into a narrow band on said food product thereby to apply a clearly-defined sear line to the outer surface of the food product; and cooling the food product during its heat treatment.

8. A method of applying a sear line to a sausage, substantially as hereinbefore described with reference to the accompanying drawings.