GB1591821A

GB1591821A - Temperature treatment of an article

Info

Publication number: GB1591821A
Application number: GB25759/77A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-05-23
Filing date: 1978-05-23
Publication date: 1981-06-24

Description

(54) TEMPERATURE TREATMENT OF AN ARTICLE (71) We, PETER JOHN GODDARD, of 4 Marlborough Place, Hixet Wood, Chari- bury, Oxford, OX7 3SH, JOHN DAVID BAUM, of 12 Beech Road, Headington, Oxford, and PETER ROLFE, of 9 Henwood Drive, Henwood, Boars Hill, Oxford, all of British nationality, do hereby declare the in invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to temperature treatment of an article and more particularly, though not exclusively, to the pasteurisation of human milk. The invention also finds apP plication for example to the sterilisation of human blood plasma prior to routine biochemical analyses of other biological material (human or animal) before pathological analysis.

It is known to pasteurise human milk and then store it in a deep-freeze so that it can subsequently be warmed and used in particular for feeding premature-born babies. Such pasteurisation is generally carried out by pasteurising milk in a large container and then, when the milk is cool, pouring it into sterilised feeding bottles. A disadvantage with this method is that there is a risk of the milk becoming contaminated when it is poured into the bottles. Thus, it is preferable to pour unpasteurised milk into the bottles first and then carry out a pasteurisation process. Moreover, it is most important that the entire pasteurisation process be accurately reproducible under all anticipated conditions.

According to one aspect of the invention there is provided a method of temperature treating an article, comprising the successive steps of subjecting the article, standing in a first liquid in a temperature treatment bath, to a first temperature treatment due to the temperature of said first liquid, emptying the bath of that liquid, and pumping a preset quantity of second liquid stored at a preset temperature into the empty bath, so that the container is then standing in said second liquid to commence a further temperature treatment phase for the article at a different temperature.

As adapted to the pasteurisation of milk, the method comprises raising unpasteurised milk in a container to a pasteurising temperature, cooling a body of stored liquid to a preset temperature prior to completion of pasteurisation of the milk, and, when pasteurisation is completed, subjecting the milk to rapid cooling by pumping a preset quantity of the stored liquid at said preset temperature into an empty haji in which the container is positioned, so that the container then stands in the cool liquid.

According to another aspect of the invention there is provided apparatus for temperature treatment of an article, comprising a temperature treatment bath and a storage bath each for containing liquid, means arranged to maintain the temperature - of liquid in each bath at a respective preset value, means operable to empty liquid from the temperature treatment bath and means operable to transfer a preset quantity of liquid in the second bath into the first bath, the arrangement being such that an article standing in liquid in the tem perature treatment bath and thereby subjected to a first temperature treatment phase due to the temperature of the first liquid can be sub jected to further temperature treatment at a different temperature by firstly emptying the first bath of the liquid therein by operating the liquid emptying means and then trans ferring said preset quantity of further liquid in the second bath into the first bath by operat ing the liquid transferring means.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawing, in which there is illustrated, diagrammatically and in plan view, one form of apparatus for the pasteurisation of human milk.

The pasteurisation apparatus, indicated generally at 1, comprises a pasteurisation bath 2 and a chilled water bath 3 arranged at a lower level than the bath 2. Both baths can be filled with water from a supply pipe 4 which discharges into the bath 2 at an outlet 5. The water level in the bath 2 rises until it reaches the height of a discharge chute 6 and then it overflows into the bath 3. As the water lever rises in the bath 3 a float 7 of a flat-operated shut-off valve 8 in the supply pipe A eventually closes the valve 8 when a preset water level is established in the bath 3.

The bath 2 is designed to accommodate a rack (not shown) capable of carrying up to forty 100 ml baby feeding plastic bottles. In addition, the bath 2 includes a heater/stirrer unit 9, which is provided with a timer and which comprises a heater with thermoset control for maintaining the temperature of the water in the bath 2 at a preset value and an electric circulation pump which takes in water from the bath and then pumps it back into the bath again, so as to stir and thoroughly mix the water in the bath. The bath 2 also includes an outlet 10 to waste, provided with a drain pump 11, and a further outlet 12 with a solenoid-operated valve 13. The outlet 12 is positioned above the bottom of the bath 2 but below the level of the chute 6 and its purpose will be explained hereinbelow.

The bath 3 is provided with a refrigeration coil 14 connected to a refrigeration unit 15 which, in use of the pasteurisation apparatus 1, is constantly in operation. The bath also incorporates a heater/stirrer unit 16 of the same construction as the unit 9 except that it does not require a timer and its theromstat has a temperature range which is designed to ensure that water in the bath is chilled to a preset temperature. An overflow 17 in the side of the bath 3 allows the water to escape to waste in the event that the valve 8 should stick in its open condition.

A circulation piple 18, including a pump 19, connects the chilled water bath to the pas teurisation bath. A bleed pipe 20 leading to waste via a solenoid-operated valve 21 is connected to a ploint in the circulation pipe 18.

The operating sequence of the apparatus will now be described: 1. Both water baths are filled with water as described above with the rack removed.

2. The solenoid-operated valve 13 is then actuated to allow water to drain from the bath 2 down to the level of the outlet 12.

The quantity of drained water corresponds to the displacement volume of the rack, with bottle compartments filled, when in position in the bath 2.

3. With the feeding bottle rack removed from the bath 2, the heater/stirrer unit 9 is switched on. Also, the heater/stirrer unit and refrigeration unit of the chilled water bath 3 are switched on.

4. When the water temperature of the pasteurisation bath is at the value set on the thermostat (e.g. substantially 63"C), the rack, containing bottles filled with unpasteurised human milk, is lowered into the pasteurisation bath and the timer of the unit 9 is switched on.

The pasteurisation process now proceeds.

5. When the timer switches off at the end of the pasteurisation treatment at the hot water temperature (before which time the water temperature of the chilled water bath will have reached the value set on the thermostat, e.g. 70C), the pump 11 is operated to drain the hot water out of the bath 2.

6. When the bath is empty, the drain pump is switched off and the pump 19 switched on to pump chilled water into the bath 2 and thereby rapidly cool the milk in the bottles.

7. As the chilled water is pumped from the bath 3, the water level falls to cause the valve 8 to open and thereby restore the water level in the bath 3 owing to the freshly supplied water mixed with the chilled water in the bath 2 overflowing down the chute 6. The valve 8 closes when both water levels have returned to their previous values.

8. The water is circulated continuously from bath 3 to bath 2 by way of the circulation pipe 18, returning via the chute 6, for about 30 minutes. Initially, the water temperature will rise significantly, because of heat transferred from the hot milk and since the fresh water supplied through the pipe 4 will generally be at a higher temperature than the temperature set on the thermostat of the heater/ stirrer unit 16. However, the water temperature is soon lowered by the refrigeration unit to reach the set temperature again eventually.

9. The rack is removed from the pasteurisation bath and the bottles are then put in deepfreeze storage, ready for subsequent use.

10. The next batch of bottles, containing unpasteurised milk, is placed in the rack and then the pasteurisation process as described above carried into effect, starting at step 2.

The maximum temperature of the circulating water during step 8 may, in some circumstances, exceed the temperature of the fresh water supplied through the pipe 4. In that event, the solenoid-operated valve 21 can be operated to bleed some of the water to waste.

The valve is of course closed once the temperature of the circulating water falls below that of the fresh water supplied.

Conveniently, the whole operating sequence of the pasteurisation apparatus can be controlled by an electrical control unit, shown diagrammatically at 22, which may incorporate an adjustable multi-cam timer. Then, at the end of a complete operating cycle, the control unit automatically switches off the apparatus and re-sets the timer, so that the apparatus is ready for the next cycle.

After heating in a pasteurisation process it is desirable to cool milk in a controlled and accurately reproducible fashion irrespective of the ambient temperature and it will be applreciated that this result can be achieved with the apparatus described where the water temperature of the chilled water bath is below ambient temperature. The results of experiments conducted to date have shown that holding the milk temperature at substantially 63"C for substantially 30 mins and then cooling radidly produces good results as far as concerns destroying harmful micro-organisms while retaining the beneficial properties of the milk.

An important use which is envisaged for the apparatus disclosed herein is in the sterilisation of blood plasma specimens. Such specimens are commonly investigated when carrying out medical tests on patients but the personnel handling the specimens are at risk of contacting such diseases as hepatitis. The apparatus disclosed above can be used for sterilising merely by appropriately setting the thermostat and timer of the heater/stirrer unit of the hot water bath. Of course, the apparatus could be used for temperature treatment in volving low templerature treatment followed by high temperature treatment and of other articles than bottles of milk or of blood plasma.

WHAT WE CLAIM IS:- 1. A method of temperature treating an article, comprising the successive steps of subjecting the article, standing in a first liquid in a temperature treatment bath, to a first temperature treatment due to the temperature of said first liquid, emptying the bath of that liquid, and pumping a preset quantity of second liquid stored at a preset temperature into the empty bath, so that the container is then standing in said second liquid to commence a further temperature treatment phase for the article at a different temperature.

2. A method of pasteurising milk, com- prising raising unpasteurised milk in a container to a pasteurising temperature, cooling a body of stored liquid to a preset temperature prior to completion of pasteurisation of the milk, and, when pasteurisation is completed, subjecting the milk to rapid cooling by pumping a preset quantity of the stored liquid at said preset temperature into an empty bath in which the container is positioned, so that the container then stands in the cool liquid.

3. A method according to claim 2, wherein the temperature of the milk is raised to a pasteurising temperature by hot water in said bath, and the bottles are subjected to thermal shock by firstly emptying the bath of hot water and then pumping chilled water, in a further bath, into the first-mentioned bath.

4. A method according to claim 3, wherein during the pumping of the chilled water into the bath, fresh cooling water is supplied until respective predetermined water levels are restored in the two baths, the water mixture being continuously recirculated between the two baths, via a refrigeration unit.

5. A method according to claim 2, 3 or 4, wherein the preset temperature is substantially 7"C.

6. A method according to any preceding claim, wherein the milk is held at a pasteurising temperature of substantially 63"C for substantially 30 minutes.

7. A method of pasteurising milk, substantially as hereinbefore described with reference to the accompanying drawing.

8. Apparatus for temperature treatment of an article, comprising a temperature treatment bath and a storage bath each for containing liquid, means arranged to maintain the temperature of liquid in each bath at a respective preset value, means operable to empty liquid from the temperature treatment bath and means operable to transfer a preset quantity of liquid in the second bath into the first bath, the arrangement being such that an article standing in liquid in the temperature treatment bath and thereby subjected to a first temperature treatment phase due to the temperature of the first liquid can be subjected to further temperature treatment at a different temperature by firstly emptying the first bath of the liquid therein by operating the liquid emptying means and then transferring said preset quantity of further liquid in the second bath into the first bath by operating the liquid transferring means.

9. Apparatus according to claim 8 and further comprising means for controlled supply of liquid to the storage baths so as to maintain in each bath a respective predetermined level of liquid, the liquid transferring means comprising a pump operable to empty liquid in the storage bath into the temperature treatment bath.

10. Apparatus according to claim 9, wherein the liquid supply control means comprises a liquid supply pipe for the temperature treatment bath, a liquid discharge chute from the temerature treatment bath, which allows liquid in the temperature treatment bath to overflow into the storage bath once the liquid in the temperature treatment bath reaches a predetermined level, and a float operated shutoff valve, associated with the storage bath, which is connected in said liquid supply pipe discharging into the first bath and is arranged to cut-off the liquid supply to the temperature treatment bath when the liquid in the storage bath reaches a predetermined level.

11. Apparatus according to any one of claims 8 to 10, wherein the temperature changing means associated with the temperature treatment bath comprises a heaterlstirrer unit with a settable thermostat and the temperature changing means associated with the storage bath comprises a refrigeration coil in that bath, connected to a continuous operation refrigeration unit, and a heater/stirrer unit with a settable thermostat.

12. Apparatus according to any one o claims 8 to 11, wherein the temperature changing means associated with the temperature treatment bath is provided with a timer which is arranged to bring the liquid emptying means into operation a preset time after temperature treatment at the first temperature has commenced.

13. Apparatus according to claim 9 or to claim 10, 11 or 12 as appended to claim 9,

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. while retaining the beneficial properties of the milk. An important use which is envisaged for the apparatus disclosed herein is in the sterilisation of blood plasma specimens. Such specimens are commonly investigated when carrying out medical tests on patients but the personnel handling the specimens are at risk of contacting such diseases as hepatitis. The apparatus disclosed above can be used for sterilising merely by appropriately setting the thermostat and timer of the heater/stirrer unit of the hot water bath. Of course, the apparatus could be used for temperature treatment in volving low templerature treatment followed by high temperature treatment and of other articles than bottles of milk or of blood plasma. WHAT WE CLAIM IS:-

1. A method of temperature treating an article, comprising the successive steps of subjecting the article, standing in a first liquid in a temperature treatment bath, to a first temperature treatment due to the temperature of said first liquid, emptying the bath of that liquid, and pumping a preset quantity of second liquid stored at a preset temperature into the empty bath, so that the container is then standing in said second liquid to commence a further temperature treatment phase for the article at a different temperature.

wherein the temperature treatment bath is provided with an outlet including a control valve, the outlet being so positioned as to allow a predetermined quantity of liquid, intended to correspond to the immersion volume of the said article, to be emptied from the temperature treatment bath prior to immersion of the said article.

14. Apparatus according to claim 9 or any one of claims 10 to 13 as appended to claim 9, wherein the pump is incorporated in a circulation pipe interconnecting the two baths, the circulation pipe being provided with a bleed pipe to waste having a control valve.

15. Apparatus according to claim 10 or any one of claims 11 to 14 as appended to claim 10, further comprising a control unit programmed to control the operating sequence of the apparatus, which sequence comprises, at least, maintaining the pump operating once it has started to transfer liquid in the storage bath into the temperature treatment bath, so as to maintain a circulation of liquid between the two baths until the second temperature treatment phase has been completed.

16. Apparatus according to claim 12, or to claim 13, 14 or 15 as appended to claim 12, and for use in the pasteurisation of human milk, wherein the temperature changing means associated with the temperature treatment bath is set to maintain the liquid temperature at substantially 63"C, and wherein the timer is set to operate the liquid emptying means after a preset time of 30 minutes.

17. Apparatus according to claim 16, wherein the temperature changing means associated with the second bath is set to maintain the liquid temperature at substantially 70C.

18. Apparatus for the temperature treatment of an article, substantially as hereinbefore described with reference to the accompanying drawing.