GB2509515A

GB2509515A - Milk cooling system

Info

Publication number: GB2509515A
Application number: GB1300131.8A
Authority: GB
Inventors: Alastair Wilson
Original assignee: DRILLING AND PUMPING SUPPLIES Ltd
Current assignee: DRILLING AND PUMPING SUPPLIES Ltd
Priority date: 2013-01-04
Filing date: 2013-01-04
Publication date: 2014-07-09
Anticipated expiration: 2033-01-04
Also published as: GB201300131D0; GB2509515B

Abstract

A milk cooling system 10 comprises a first tank 12 containing, in use, a quantity of milk; a second tank 14 for storing cooled milk; a cooling apparatus 16 comprising a heat exchanger (for example a plate heat exchanger); and a third tank 26 containing, in use, a quantity of a cooling fluid (for example water). One or more conduits are provided for providing a fluid flow passage between the first tank and the second tank via the cooling apparatus. The third tank and the cooling apparatus are connected by a fluid flow circuit 28 from the third tank through the heat exchanger and back to the third tank. During operation the system pumps milk (continuously or sporadically) from the first tank to the second tank via the said fluid flow passage and pumps cooling fluid around the fluid flow circuit (using a pump system 34). The cooling fluid may be pumped through the heat exchanger at a rate of at least 100 litres per minute but may be pumped at a flow rate of up to 300 litres per minute.

Description

MILK COOLING SYSTEM

FIELD OF THE INVENTION

S The present invention relates to milk cooling systems.

BACKGROUND TO THE INVENTION

Milk produced from a milking parlour must be cooled before it is stored. Conventionally milk is pumped from a temporary storage tank to a main storage tank via a heat-exchanging unit commonly referred to as a plate cooler. The plate cooler is flushed with a quantity of relatively cool water in order to provide a cooling effect on the milk. Once the water is flushed through the plate cooler it is normally considered to be of no further use to the cooling system and so it is dumped for use in another application for example washing down cow stalls, or to a slurry pit. Conventional systems are therefore considered to be wasteful and, as a result, users tend to restrict the quantity of water that is flushed through the plate cooler. However this in turn limits the cooling effect that the plate cooler has on the milk. As a result the main milk storage tank, which is typically refrigerated, must work harder to refrigerate the stored milk.

Another problem with conventional systems is that milk tends to be pumped from the temporary storage tank to the main storage tank sporadically. As a result users tend to attempt to control the flushing of water through the plate cooler to coincide with the delivery of milk to the plate cooler, which adds to the complication of the system.

It would be desirable to provide a milk cooling system that mitigates the problems outlined above.

SUMMARY OF THE INVENTION

A first aspect of the invention provides a milk cooling system comprising first tank containing, in use, a quantity of milk, or otherwise being connectable to a source of milk; a second tank for storing cooled milk; a cooling apparatus comprising a heat exchanger; a third tank containing, in use, a quantity of a cooling fluid; one or more conduits for connecting said first tank, or source of milk, to said second tank via said cooling apparatus and configured to define a fluid flow passage from said first tank, or other source of milk, to said second tank through said heat exchanger; one or more conduits connected between said third tank and said cooling apparatus to create a fluid flow circuit from said third tank through said heat exchanger and back to said third tank; pumping means configured to pump milk from said first tank, or other source of milk, to said second tank via said fluid flow passage; and pumping means configured to pump cooling fluid around said fluid flow circuit.

Preferably said pumping means for pumping cooling fluid around said fluid flow circuit is operated to pump, in use, said cooling fluid through said heat exchanger at a rate of at least 100 litres per minute, preferably at least 180 litres per minute. More preferably said rate is approximately 200 to 300 litres per minute.

Preferably, said heat exchanger comprises a plate heat exchanger.

S

Typically, said second tank includes refrigeration means for refrigerating contents of the tank.

Typically, said cooling fluid is a liquid, conveniently water.

In a preferred mode of operation said pumping means for pumping cooling fluid around said circuit is operated to pump, in use, said cooling fluid continuously around said circuit.

Typically, said pumping means for pumping milk through said heat exchanger is operated in use to pump said milk sporadically through the heat exchanger.

IS

A second aspect of the invention comprises a method of cooling milk in a milk cooling system according to the first aspect of the invention, the method comprising pumping milk from said first tank, or other source, to said second tank through said heat exchanger; and pumping cooling fluid around said fluid flow circuit. Preferably said method involves pumping said cooling fluid through said heat exchanger at a rate of at least 100 litres per minute, preferably at least 180 litres per minute.

Preferably said rate is approximately 200 to 300 litres per minute.

Preferably said method includes pumping said cooling medium continuously through said heat exchanger. Typically said method includes pumping said milk sporadically through said heat exchanger.

Further advantageous aspects of the invention will become apparent to those ordinarily skilled in the art upon review of the following description of a specific embodiment and with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention is now described by way of example and with reference to the accompanying drawing which is a schematic diagram of a milk cooling system embodying the invention.

DETAILED DESCRIPTION OF THE DRAWING

Referring to the drawing there is shown generally indicated as 10 a milk cooling system embodying the invention. The system 10 includes, or is connectable to, a temporary storage tank 12 for receiving milk produced from a milking parlour, or to another source of milk. In use the milk received by tank 12 tends to be relatively warm (for example approximately 350 celsius). It is necessary to store the milk at a relatively low temperature (typically approximately 4° celsius). A main tank 14 is provided for storing the relatively cool milk. The main tank 14 is usually a refrigerated tank and to this end may be equipped with any suitable conventional refrigeration apparatus (not shown). To S reduce the amount of work that the refrigeration tank 14 has to do to cool the milk, the milk is sent from the temporary storage tank 12 to the main tank 14 via a cooling apparatus 16, typically comprising a heat exchanger. Usually, a pump system (not shown) is provided for pumping milk from the temporary tank 12 to the main tank 14 via the cooling apparatus 16. The cooling apparatus 16 comprises a first structure for carrying the milk between a milk inlet 18 and a milk outlet 20, a second structure for carrying a cooling medium between a cooling medium inlet 22 and a cooling medium outlet 24. The first and second structures may take any convenient form but typically define a respective one or more fluid passages for the milk or cooling medium through the apparatus 16.

The respective passages are separated by one or more walls or other structures that allow heat exchange to take place between the cooling medium and the milk as the two pass through the apparatus 16. In typical embodiments, the cooling apparatus 16 comprises a plate heat-exchanger.

The cooling medium may comprise any suitable fluid, is typically a liquid, and most commonly comprises water. The fluid is carried from the tank 12 to the tank 14 by any suitable conduit(s), typically comprising pipes.

The system 10 includes a tank 26 for holding the cooling medium. The tank 26 preferably has a storage volume of at least 24,000 litres. A fluid flow circuit 28 is provided between the tank 26 and the apparatus 16 to allow the cooling medium to be circulated and re-circulated between the tank 26 and the cooling apparatus 16. In particular the circuit 28 is configured to provide a forward fluid flow path between an outlet 30 of the tank 26 and the inlet 22 of the cooling apparatus 16, and a return fluid flow path between the outlet 24 of the cooling apparatus 16 and an inlet 32 of the tank 26. The circuit 28 may be provided by any suitable conduit(s), typically comprising pipes.

A pump system, for example comprising pump 34, is provided for pumping the cooling medium around the circuit 28, and in particular from the tank 26 through the cooling apparatus 16 and back to the tank 26. Any conventional suitable pump(s) may be used for this purpose. In the illustrated embodiment the pump 34 is shown in the forward flow path from the tank 26 to the cooling apparatus 16, although it may alternatively be located elsewhere in the circuit 28. By way of example, in a typical system the pump may have a capacity of pumping at least 180 litres per minute.

A filter, for example a high flow filter, may be provided in the circuit 28, typically in the forward path, for removing contaminants from the cooling medium in order to prevent build-up of sediment or dirt in the cooling apparatus 16.

In a preferred mode of use, the pump 34 is operated to continuously pump the cooling medium between the tank 26 and cooling apparatus 16 via circuit 28. In typical embodiments, the pump 34 is preferably operated to pump the cooling medium at at least 180 litres per minute, preferably between approximately 200 and 300 litres per minute. More generally, the size (capacity) of the pump may be selected to suit one or more characteristics of the system 10, for example the size of the heat exchanger, and/or the size and/or length of the pipework use to provide the circuit 28.

S In preferred embodiments, during use the pump 34 is operated to pass the cooling medium through the heat exchanger 16 at a rate that is more than or substantially equal to the rate at which milk is passed through said heat exchanger 16. In this regard, the milk rate-to-cooling medium rate may have a ratio of approximately 1:1 or 1:1.4 in typical embodiments. More generally, the ratio may be in the range 2:1 to 1:2, preferably within the range 1:1 to 1:1.5. In typical embodiments, the milk pump (not shown) operates at its instantaneous maximum flow rate. The flow rate implemented by pump 34 for the cooling medium may therefore be set depending on the instantaneous maximum flow rate of the milk pump, advantageously in accordance with the preferred ratios.

Advantageously, because the cooling medium is pumped relatively quickly through the heat exchanger 16, it is not heated by a significant amount as it passes through the heat exchanger. This makes the cooling medium suitable for recycling via the tank 26. Moreover the relatively large rate of flow of the cooling medium through the heat exchanger has a relatively large cooling effect on the milk in comparison with a conventional system. Hence, the systems embodying the invention are capable of having a relatively high cooling effect on the milk at the cooling apparatus 16 while conserving the cooling medium by recycling it. It is found that preferred embodiments of the invention can cool milk by approximately 20° celsius as it passes through the cooling plate 16.

In contrast, conventional systems typically only reduce the milk temperature by approximately 5° to 10° celsius. Moreover, in conventional systems the water is flushed through the heat exchanger at relatively slow rates, typically between 30 and 50 litres per minute, as a result of which not only does it have a poor cooling effect on the milk but it also tends to become relatively heated itself which makes it unsuitable for recycling.

Furthermore, because the cooling medium of the system 10 can be recycled, it is feasible to operate pump 34 continuously and so this removes the need for any relatively complicated control equipment which may otherwise be required to attempt to synchronise the flow of cooling medium through the cooling apparatus 16 with the flow of milk to the cooling apparatus 16.

The invention is not limited to the embodiment(s) described herein which can be modified or varied without departing from the scope of the present invention.

Claims

CLAIMS: 1. A milk cooling system comprising first tank containing, in use, a quantity of milk, or otherwise being connectable to a source of milk; a second tank for storing cooled milk; a cooling apparatus S comprising a heat exchanger; a third tank containing, in use, a quantity of a cooling fluid; one or more conduits for connecting said first tank, or source of milk, to said second tank via said cooling apparatus and configured to define a fluid flow passage from said first tank, or other source of milk, to said second tank through said heat exchanger; one or more conduits connected between said third tank and said cooling apparatus to create a fluid flow circuit from said third tank through said heat exchanger and back to said third tank; pumping means configured to pump milk from said first tank, or other source of milk, to said second tank via said fluid flow passage; and pumping means configured to pump cooling fluid around said fluid flow circuit.
2. A system as claimed in claim 1, wherein said pumping means for pumping cooling fluid around said fluid flow circuit is operated to pump, in use, said cooling fluid through said heat exchanger at a rate of at least 100 litres per minute, preferably at least 180 litres per minute.
3. A system as claimed in claim 2, wherein said rate is approximately 200 to 300 litres per minute.
4. A system as claimed in any preceding claim, wherein said heat exchanger comprises a plate heat exchanger.
S. A system as claimed in any preceding claim, wherein said second tank includes refrigeration means for refrigerating contents of the tank.
6. A system as claimed in any preceding claim, wherein said cooling fluid is a liquid, conveniently water.
7. A system as claimed in any preceding claim, being operable in a mode of operation in which said pumping means for pumping cooling fluid around said circuit is operated to pump, in use, said cooling fluid continuously around said circuit.
8. A system as claimed in any preceding claim, wherein said pumping means for pumping milk through said heat exchanger is operated in use to pump said milk sporadically through the heat exchanger.
9. A system as claimed in any preceding claim, wherein, during said pumping means for pumping said cooling fluid is operated to pump the cooling fluid through the heat exchanger at a rate that is more than or substantially equal to the rate at which said pumping means for pumping milk through said heat exchanger is operated in use to pump said milk through the heat exchanger.
10. A method of cooling milk in a milk cooling system comprising first tank containing, in use, a quantity of milk, or otherwise being connectable to a source of milk; a second tank for storing cooled milk; a cooling apparatus comprising a heat exchanger; a third tank containing, in use, a quantity of a cooling fluid; one or more conduits for connecting said first tank, or source of milk, to said second S tank via said cooling apparatus and configured to define a fluid flow passage from said first tank, or other source of milk, to said second tank through said heat exchanger; one or more conduits connected between said third tank and said cooling apparatus to create a fluid flow circuit from said third tank through said heat exchanger and back to said third tank; pumping means configured to pump milk from said first tank, or other source of milk, to said second tank via said fluid flow passage; and pumping means configured to pump cooling fluid around said fluid flow circuit, the method comprising pumping milk from said first tank, or other source, to said second tank through said heat exchanger; and pumping cooling fluid around said fluid flow circuit.
11. A method as claimed in claim 10, comprising pumping said cooling fluid through said heat exchanger at a rate of at least 100 litres per minute, preferably at least 180 litres per minute.
12. A method as claimed in claim 11, wherein said rate is approximately 200 to 300 litres per minute.
13. A method as claimed in any one of claims 10 to 12, wherein said method includes pumping said cooling medium continuously through said heat exchanger.
14. A method as claimed in any one of claims 10 to 13, wherein said method includes pumping said milk sporadically through said heat exchanger.
15. A method as claimed in any one of claims 10 to 14, wherein said method includes pumping said cooling fluid through the heat exchanger at a rate that is more than or substantially equal to the rate at which milk is pumped through said heat exchanger.
16. A method as claimed in claim 15, wherein the ratio of the milk flow rate to the cooling fluid flow rate is between approximately 1:1 and 1:1.5.