AN APPARATUS AND A METHOD FOR THE HEAT TREATMENT OF A FLOW OF PUMPABLE FOOD PRODUCT

Abstract: The disclosure relates to an apparatus for the heat treatment of a flow of pumpable food product, comprising one or more units for preheating and heating of the food product to a predetermined temperature, a buffer pipe through which the food product passes, and in which this temperature is maintained during a predetermined stay time, and one or more coolers. According to the invention, the buffer pipe is designed such that its length may be modified by at least a portion of the buffer pipe being of such construction that it may function either as a buffer pipe or as a cooler. The disclosure also relates to a method for the continuous heat treatment of a flow of a pumpable food product using an apparatus according to the invention.

Description: AN APPARATUS AND A METHOD FOR THE HEAT TREATMENT OF A FLOW OF PUMPABLE FOOD PRODUCT TECHNICAL FIELD The present invention relates to an apparatus for the heat treatment of a flow of pumpable food product, and a method of continuously heat treating a pumpable food product in such an apparatus. BACKGROUND ART In the heat treatment of a food product for the purposes of achieving, for example, the pasteurization or sterilization of the product, the food product is heated to a predetermined temperature and is held at that temperature for a given time. If the stay time at the disclosed temperature is too short, the desired effect will not be achieved - in pasteurization the destruction of all pathogenic micro-organisms. If the stay time is overly long, there is a risk of affecting the various substances included in the food product, which may alter their flavour or aroma. An apparatus for such heat treatment comprises one or more units for preheating and heating the food product to a predetermined temperature, and a buffer pipe through which the food product passes and in which this temperature is maintained for a predetermined time, together with one or more coolers. The buffer pipe normally consists of a pipe coil of a given length. The length of the pipe coil then corresponds to treatment of a given product at a given calculated capacity of the heat treatment apparatus. The flow rate through the apparatus - and thereby through the buffer pipe - normally depends upon the performance of the heating unit and the coolers and is, thereby, relatively constant. SUMMARY OF THE INVENTION According to the present invention, there is now proposed an apparatus for the heat treatment of food products which may readily be adapted to different requirements in the form of stay times at desired elevated temperature. The apparatus according to the invention is substantially characterized in that the buffer pipe is designed such that its length may be modified in that at least a portion of the buffer pipe is of such construction that it may operate either as a buffer pipe or as a cooler. With CONFIRMATION COPY such a construction, the stay time may be adapted, on the one hand to changes in the product composition, and, on the other hand, to modified flows of the food product. The apparatus is advantageously designed such that the above described portion of the buffer pipe is adjacent to or is surrounded by a space which may be connected to a coolant. As was mentioned above, the buffer pipe normally consists of a pipe coil, but it is also conceivable to utilise instead a helically wound pipe of optional cross section, or to utilise a plate apparatus of the plate heat exchanger type, specifically constructed for this purpose. Depending upon the design and construction selected, the cooling surface facing the buffer pipe will be of varying configuration. However, the buffer pipe preferably consists in a first portion of a pipe coil of cylindrical configuration and, in a section portion of the buffer pipe seen in the flow direction, the above-described space consists of one or more sections of double-jacketed pipes, these sections being capable, when necessary, of acting as coolers. These sections are suitably designed such that they may be connected stepwise to the coolant. Temperature sensors, or guards, for sensing the temperature of the food product are provided at the end of the above-disclosed pipe coil and between the above-described sections. The method for continuous heat treatment of a pumpable food product according to the present invention is substantially characterized in that the stay time in the buffer pipe for the food product at the predetermined temperature is modifiable during one operation period. In the method according to the present invention, both the thermal load and the bacteriological effect may thus remain unchanged if an intentional modification or an unforeseen disruption were to occur. In the method according to the present invention, the stay time may be modified by an increase or reduction thereof if the flow of food product increases or decreases while an operational period is in progress. If the flow of food product is adjustable between one or more capacities, the stay time will consequently also be modified stepwise in that one or more cooling stages are brought into operation. The method according to the present invention may also be utilized by an adaptation of the stay time to suit the consistency or particle content of the food product at a given flow rate capacity. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING The apparatus according to the present invention will now be described in greater detail hereinbelow, with particular reference to the accompanying Drawing which shows one embodiment of the apparatus chosen by way of example. DESCRIPTION OF PREFERRED EMBODIMENT The Drawing shows a portion 1 of a tubular buffer pipe according to the present invention. In the second portion 2 seen in the flow direction, the buffer pipe consists of sections 3, 4 and 5 of double-jacketed piping. These sections are provided with valved connections 6, 7 and 8 to a coolant circuit 9. The cooling side of each section 3, 4 and 5 is in communication with the coolant circuit 9 by the intermediary of outlets 10, 11 and 12. Three-way valves 13, 14 and 15 are provided at the inlets 6, 7 and 8 to the sections 3, 4 and 5. At the end of the first portion 1 of the buffer pipe, there is disposed a temperature sensor or guard 16 which senses the temperature of the product. There is also a temperature guard disposed between the sections 3, 4 and 5. The apparatus shown on the Drawing functions as follows. Food product which is heated to the desired temperature passes the first portion 1 of the buffer pipe. If the longest possible stay time is to be achieved, the food product passes further through the inner pipe in sections 3, 4 and 5, and the communication pipes between them, and further to a cooler (not shown) disposed after the buffer pipe. If a slightly shorter stay time is desired, coolant is led from the coolant circuit 9 into the coolant section 5 though the valve 8 and the connection 10 and departs from the coolant section through the connection outlet 10. The product which, in the case described earlier, is not cooled until in the cooler (not shown), is now cooled already in the last portion of the buffer pipe, and the stay time at the predetermined temperature is shortened somewhat. In a manner corresponding to that described above, sections 3 and 4 may be activated in that coolant is caused to pass the coolant section 4 through the valve 13, connections 7 and 10, and the coolant section 3 via the valve 12 and connections 6 and 9. The earlier the product is cooled, the shorter the stay time will be. The temperature is monitored by means of the temperature sensors or guards 16-18. As coolant in the buffer pipe, use may be made of the coolant which is employed in the indirectly acting heat exchanger connected after the buffer pipe. An apparatus of the type shown in the Drawing may, for example, be employed in the high temperature treatment or pasteurization of milk in connection with filling into packages. Should any of the filling machines break down for one reason or another, the milk flow may be reduced and the stay time adapted to the new, reduced flow. In the embodiment shown on the Drawing, the buffer pipe is switchable between capacities 1 to 4. Naturally, the number of steps may vary without departing from the spirit and scope of the inventive concept as herein disclosed. An apparatus of the type described in the foregoing may also advantageously be employed in the heat treatment of food products of high viscosity or containing particles. In such a practical application, the possibility of being able to customise stay time in an existing installation may of major value. The present invention should not be considered as restricted to that described above and shown on the Drawing, many modifications being conceivable without departing from the spirit and scope of the appended Claims.

Claims: WHAT IS CLAIMED IS: 1. An apparatus for the heat treatment of a flow of pumpable food product, comprising one or more units for preheating and heating of the food product to a predetermined temperature, and a buffer pipe through which the food product passes, and in which this temperature is maintained during a predetermined stay time, and one or more coolers, characterized in that the buffer pipe is designed such that its length may be modified by at least a portion of the buffer pipe being of such construction that it may function either as a buffer pipe or as a cooler. 2. The apparatus as claimed in Claim 1, characterized in that said portion of the buffer pipe is adjacent to or is surrounded by a space which may be connected to a coolant. 3. The apparatus as claimed in Claim 2, characterized in that the buffer pipe consists, in a first portion, of a cylindrical pipe coil; and that in a second portion seen in the direction of flow, said space consists of one or more sections of double-jacketed cylindrical piping, these sections being capable, when necessary, of operating as coolers. 4. The apparatus as claimed in Claim 3, characterized in that said sections are designed to be able to be connected stepwise and in series to the coolant. 5. The apparatus as claimed in Claim 2, characterized in that temperature sensors or guards are provided for sensing the temperature of the food product at the end of the pipe coil and between each respective section. 6. A method for the continuous heat treatment of a flow of a pumpable food product in an apparatus as claimed in Claim 1, characterized in that the say time of the food product at the predetermined temperature may be changed during an operational period. 7. The method as claimed in Claim 4, characterized in that the flow of food product during an ongoing operational period increases or alternatively decreases, implying that the stay time must be modified by an increase or a decrease thereof. 8. The method as claimed in Claim 5, characterized in that the flow of food product during an operational period is switchable between one or more capacities, it being possible to modify the stay time by the bringing into operation of one or more cooling stages. 9. The method as claimed in Claim 6, characterized in that the stay time in the buffer pipe is adapted to the consistency or particle content of the food product at a given flow capacity.

Inventors: ARPH STEN-OLOF, PALM BENGT, ARPH, STEN-OLOF, PALM, BENGT
Applicants: ARPH STEN OLOF, PALM BENGT, TETRA LAVAL HOLDINGS & FINANCE, ARPH, STEN-OLOF, PALM, BENGT, TETRA LAVAL HOLDINGS & FINANCE S.A.
Application year: 1996
Main classification: A23L3
IPC codes: A23C3, A23L3