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GB1598803A - Control circuit for pasteuriser - Google Patents

Control circuit for pasteuriser Download PDF

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Publication number
GB1598803A
GB1598803A GB9115/77A GB911577A GB1598803A GB 1598803 A GB1598803 A GB 1598803A GB 9115/77 A GB9115/77 A GB 9115/77A GB 911577 A GB911577 A GB 911577A GB 1598803 A GB1598803 A GB 1598803A
Authority
GB
United Kingdom
Prior art keywords
temperature
comparator
milk
solenoid
control
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB9115/77A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EDONI REFRIGERATION Ltd
Original Assignee
Edoni Refrigeration Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Edoni Refrigeration Ltd filed Critical Edoni Refrigeration Ltd
Priority to GB9115/77A priority Critical patent/GB1598803A/en
Publication of GB1598803A publication Critical patent/GB1598803A/en
Application status is Expired legal-status Critical

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Classifications

    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05DSYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00Control of temperature
    • G05D23/19Control of temperature characterised by the use of electric means
    • G05D23/275Control of temperature characterised by the use of electric means with sensing element expanding, contracting, or fusing in response to changes of temperature
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05DSYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00Control of temperature
    • G05D23/19Control of temperature characterised by the use of electric means
    • G05D23/1902Control of temperature characterised by the use of electric means characterised by the use of a variable reference value
    • G05D23/1904Control of temperature characterised by the use of electric means characterised by the use of a variable reference value variable in time

Description

(54) CONTROL CIRCUIT FOR PASTEURISER (71) We, EDONI REFRIGERATION LIMITED, a British Company, of 100 Strathmore Road, Balmore Estate, Glasgow G22, Great Britain, do hereby declare the 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: This invention relates to an electrical control circuit for controlling the individual elements of a food treatment apparatus such as a pasteurising system.

In a batch milk pasteuriser, the various stages of pasteurising, that is, heating to 145"F, maintaining the milk at this temperature for a period of approximately 30 minutes, cooling the-milk to approximately 65"F and thereafter storing the milk at approximately 40 F, can be carried out in a single vat. The various elements of the pasteuriser, i.e., heaters, coolers, agitators, etc., are controlled by solenoid valves operated by manual switches. In order to ensure that the milk is subjected to the correct process it has been necessary hitherto to supervise the operation of the pasteuriser in order that the switches controlling each of the elements is operated at the correct time.

A disadvantage of such systems is that much labour is consumed in supervision and also, there is no guarantee that the process has been correctly carried out.

It is an object of the present invention to obviate or mitigate the disadvantages of the prior manually operated systems.

According to the present invention there is provided in an apparatus for treating a foodstuff by heat treatment and storage at predetermined temperatures, an electrical control circuit comprising transducer means for providing a signal representative of the temperature of the foodstuff, comparator means arranged to produce a first control signal when the foodstuff reaches a first predetermined temperature and a second control signal when it reaches a second predetermined temperature, and output means responsive to each of said control signals to operate respective heating or cooling units of the apparatus.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawing in which the single Figure is a block diagram of one embodiment of a control system in accordance with the present invention: Referring to the drawing, the control circuit of the present invention is applied to a batch pasteuriser.

The batch pasteuriser, which is only one example of a system to which the control circuit of the present invention may be applied, includes a plurality of functional elements to effect the various stages in the pasteurising process. These elements include a steam raiser for raising the temperature of the milk from its normal temperature of about 80"F to a temperature of 145-165"F.

The steam raiser is controlled by a steam raiser solenoid SR1.

After the milk has been maintained at this temperature of 145-165"F for the- required period, e.g., 30 minutes, the milk is cooled by a water flow controlled by a water flow solenoid WF1. When the milk has been brought to a temperature of approximately 65"F a refrigerator unit is actuated by means of solenoid RD1 to bring the milk to the storing temperature of just below 40"F.

The control circuit comprises a temperature probe 1 located in the pasteurising vat and producing an output signal representative of the temperature of the milk in the vat. This signal is passed to a transducer unit 2 which in turn passes a temperature representative signal to each of a plurality of temperature comparators 3a, 3b, 3c. The number of comparators in the circuit will depend on the number of elements to be controlled. Thus it can be seen that additional stages in the process may be added by the simple addition of a further comparator circuit.

The temperature comparator 3a controls the steam raiser solenoid SR1 through the associated relay RL1. Similarly, the comparator 3b controls the water flow solenoid WF1 and the comparator 3c controls the refrigerator solenoid Rid 1.

Each of the comparator circuits may contain time delay means whereby any particular temperature may be maintained for a desired period. Thus, in the present case, the comparator 3a includes a delay means for producing a delay of approximately 30 minutes so that the milk is held at a temperature of 145"F for the desired period. On closing of the start contactor, the agitator solenoid AG1 is energized, and the associated indicator light AG2 is illuminated. Since the temperature of the milk is below the reference temperature of comparator 3a, the associated relay RL1 causes the steam raiser solenoid SR1 to be actuated which raises the temperature of the milk to the desired pasteurising temperature of 145"F. The milk is maintained at this temperature for a period of 30 minutes whereafter comparator 3b takes over control.As the temperature of the milk will be above the reference temperature of the comparator 3b, i.e., approximately 65"F. Relay RL2 will be energized, activating the water flow solenoid WF1. The flow of water cools the milk to approximately 65"F at which stage the temperature comparator 3c which controls the refrigerator solenoid RD1 through relay RL3 takes over control. The temperature comparator 3c causes the refrigerator to be switched off when the temperature is approximately 40"F and causes the refrigerator to be switched on when the temperature of the milk reaches 45"F. The milk is therefore stored at this temperature until removed from the vat.

The various stages in the process are indicated by the respective lamps AG2, SR2, WF2 and RD2, the lamp RD2 indicating end of cycle.

If desired, the transducer unit 2 may include a recorder which produces a timetemperature trace of the process. The system is so designed that, should any interruption of the process occur before the refrigeration stage, then the entire cycle will have to be repeated, thus ensuring proper pasteurisation.

It will be seen thatthe control circuit may be modified to control processes for treating foodstuffs other than pasteurisation and may be used, for example, to control a process for the preparation of ice-cream.

Additionally, it is envisaged that the control circuit may be modified without departing from the scope of the invention, for example, the relays may be replaced by solid state devices.

WHAT WE CLAIM IS: 1. In an apparatus for treating a foodstuff by heat treatment and storage at predetermined temperatures, an electrical control circuit comprising transducer means for providing a signal representative of the temperature of the foodstuff, comparator means arranged to produce a first control signal when the foodstuff reaches a first predetermined temperature and a second control signal when it reaches a second predetermined temperature, and output means responsive to each of said control signals to operate respective heating or cooling units of the apparatus.

2. The apparatus of claim 1, including a steam raiser for heating the foodstuff and a controllable flow of water for cooling the foodstuff, and in which the output means comprises a first solenoid for energizing the steam raiser and a second solenoid controlling a water flow valve.

3. The apparatus of claim 2, in which the comparator means comprises first and second comparators, each arranged to produce a respective one of said control signals.

4. Food treatment apparatus substantially as herein described with reference to the drawings.

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

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. controlled. Thus it can be seen that additional stages in the process may be added by the simple addition of a further comparator circuit. The temperature comparator 3a controls the steam raiser solenoid SR1 through the associated relay RL1. Similarly, the comparator 3b controls the water flow solenoid WF1 and the comparator 3c controls the refrigerator solenoid Rid 1. Each of the comparator circuits may contain time delay means whereby any particular temperature may be maintained for a desired period. Thus, in the present case, the comparator 3a includes a delay means for producing a delay of approximately 30 minutes so that the milk is held at a temperature of 145"F for the desired period. On closing of the start contactor, the agitator solenoid AG1 is energized, and the associated indicator light AG2 is illuminated. Since the temperature of the milk is below the reference temperature of comparator 3a, the associated relay RL1 causes the steam raiser solenoid SR1 to be actuated which raises the temperature of the milk to the desired pasteurising temperature of 145"F. The milk is maintained at this temperature for a period of 30 minutes whereafter comparator 3b takes over control.As the temperature of the milk will be above the reference temperature of the comparator 3b, i.e., approximately 65"F. Relay RL2 will be energized, activating the water flow solenoid WF1. The flow of water cools the milk to approximately 65"F at which stage the temperature comparator 3c which controls the refrigerator solenoid RD1 through relay RL3 takes over control. The temperature comparator 3c causes the refrigerator to be switched off when the temperature is approximately 40"F and causes the refrigerator to be switched on when the temperature of the milk reaches 45"F. The milk is therefore stored at this temperature until removed from the vat. The various stages in the process are indicated by the respective lamps AG2, SR2, WF2 and RD2, the lamp RD2 indicating end of cycle. If desired, the transducer unit 2 may include a recorder which produces a timetemperature trace of the process. The system is so designed that, should any interruption of the process occur before the refrigeration stage, then the entire cycle will have to be repeated, thus ensuring proper pasteurisation. It will be seen thatthe control circuit may be modified to control processes for treating foodstuffs other than pasteurisation and may be used, for example, to control a process for the preparation of ice-cream. Additionally, it is envisaged that the control circuit may be modified without departing from the scope of the invention, for example, the relays may be replaced by solid state devices. WHAT WE CLAIM IS:
1. In an apparatus for treating a foodstuff by heat treatment and storage at predetermined temperatures, an electrical control circuit comprising transducer means for providing a signal representative of the temperature of the foodstuff, comparator means arranged to produce a first control signal when the foodstuff reaches a first predetermined temperature and a second control signal when it reaches a second predetermined temperature, and output means responsive to each of said control signals to operate respective heating or cooling units of the apparatus.
2. The apparatus of claim 1, including a steam raiser for heating the foodstuff and a controllable flow of water for cooling the foodstuff, and in which the output means comprises a first solenoid for energizing the steam raiser and a second solenoid controlling a water flow valve.
3. The apparatus of claim 2, in which the comparator means comprises first and second comparators, each arranged to produce a respective one of said control signals.
4. Food treatment apparatus substantially as herein described with reference to the drawings.
GB9115/77A 1978-05-31 1978-05-31 Control circuit for pasteuriser Expired GB1598803A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9115/77A GB1598803A (en) 1978-05-31 1978-05-31 Control circuit for pasteuriser

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9115/77A GB1598803A (en) 1978-05-31 1978-05-31 Control circuit for pasteuriser

Publications (1)

Publication Number Publication Date
GB1598803A true GB1598803A (en) 1981-09-23

Family

ID=9865662

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9115/77A Expired GB1598803A (en) 1978-05-31 1978-05-31 Control circuit for pasteuriser

Country Status (1)

Country Link
GB (1) GB1598803A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2158271A (en) * 1984-04-30 1985-11-06 Dominion Tool & Die Co Prestreching and tensioning flexible drive members (e.g. v-belts)
GB2175105A (en) * 1985-05-09 1986-11-19 Corby John Ltd Controlling a fabric press

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2158271A (en) * 1984-04-30 1985-11-06 Dominion Tool & Die Co Prestreching and tensioning flexible drive members (e.g. v-belts)
GB2175105A (en) * 1985-05-09 1986-11-19 Corby John Ltd Controlling a fabric press

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19920531