NZ233612A - Controller for milk tank washing machine - Google Patents

Description

233612 % \ *3MAYl99fg)j ;. * PATENTS FORM NO. 5 Fee No. 4: $200.00 ! V PATENTS ACT 1953 COMPLETE SPECIFICATION After Provisional No: 233612 Dated: 3rd Tulyi990 CONTROL SYSTEM 7 I Ian Henry Heyes, a New Zealand citizen of 14 Woods Avenue, Matua, Tauranga, New Zealand hereby declare the invention for which I/We pray that a patent may be granted to me, and the method by which it is to be performed to be particularly described in and by the following statement: 1 Cfcllcwed N ? 5 3 61 2 This invention relates to a control system and in particular a control system for controlling the washing of dairy milk tanks and modifications to control the washing of a dairy milking machine.

Collection of milk from farm milk tanks can now occur at any time during the 5 day or night. This means that the milk tank may need to be washed during the night or just before morning milking. At present, washing is usually a manual process and unfortunately it has become common for the washing process to be skimped upon when it is required to be done either late at night or in the early hours of the morning before morning milking. This can lead to 10 high bacterial counts and a lower quality of milk.

Another problem associated with current practices is that usually only one solution is used to flush to milk residues, wash the tank and to leave a sanitised surface. Understandably, this is not the most effective way to cleanse a milk tank.

Milking machines also are required to be hygienically clean and the nature of milk is such that this is often difficult to achieve by traditional washing methods.

It is an object of the present invention to provide a method and apparatus which address the above problem.

Further objects and partitions of the present invention become apparent from the following description which is given by way of example only. lA 2336 1 2 According to one aspect of the present invention there is provided an automatic control system for operating a washing cycle to cleanse a milk tank and/or a milking machine.

The term tank will be used herein to cover all containers that hold a large 5 quantity of milk such as vats and so forth.

According to a further aspect of the present invention, the control system may be used in conjunction with a cold water source, a hot water source, a wash tub wherein the flow of water into the wash tub is controlled by the control system and water from within said wash tub can flow into the milk tank 10 and/or the milking machine.

The control system may use a microprocessor.

Throughout the specification, the present invention will be described with reference to milk tanks but it should be appreciated that it is also suitable for milking machines as well.

It can be seen that the present invention overcomes problems inherent in previous practices. For instance, by having an automated control system for washing a milk tank, all that is required is for the tanker driver to flick a switch, press a button or otherwise start the washing system once the milk has been collected. Furthermore, by having a control system a number of 20 washing cycles may be initiated without requiring manual input from the farmer. This means that a thorough washing of the tank can be achieved without the farmer having to interrupt his or her duties around the farm. 2 93 '56:7 In one embodiment of the present invention, the control system may control a wash cycle comprising of three or more steps. The first step may be filling a wash tub with cold water which is then used to wash out the milk residues in the milk tank. The second step may be to have a hot water wash perhaps with some detergent which acts to wash the tank and leave a sanitised surface. Finally the third step may be to have another cold wash which acts to rinse traces of detergent or contaminants from the milk tank.

In one embodiment, the present invention may comprise a control system operatively connected to a cold water valve and to a hot water valve and one or more liquid level sensors. The hot and cold water valves may be connected to the hot and cold water supply sources which are already in place in an existing milking shed. The level sensors preferably are fitted into a wash tub and the control system can be connected to a power supply already existing in the milking shed.

The control system may have operatively connected to it a pump for pumping detergent into the wash tub. More than one pump and detergent source may be controlled by the control system. This is because mineral or protein buildup can occur in the milk tank unless there is periodically a change in the detergent used.

If the control system is to be installed in a new milking shed, it is envisaged that the following components may be used as well, namely a wash tub (maybe on a stand) with a spray pump, a suitable milk tank wash spray ball or wand and an instant hot water electric heater. 3 A wash tub enables the detergent to be mixed with the water before being sprayed into the milk tank. Furthermore, a separate tank or wash tub is useful for when the water supply flow rate is slow, for instance such as may be supplied by a continuous hot water heater. The wash tank may be filled slowly with the hot water, but once filled the spray pump can be activated to pump the hot water to the milk tank at a faster flow rate than the filling rate.

By using a continuous hot water heater, it is believed that considerable cost savings may be made as the water is only heated when it is required to be used in accordance with the control system.

By using liquid level sensors and safety sensors a number of safety features may be incorporated into the present system. For instance there may be a sensor in the milk tank which ensures that the control system can't operate if there is still milk in the tank.

Often a chiller compressor is used in the milk shed to cool the milk in the milk tank. A sensor can be used to test if the compressor is turned on. If so, then it is likely there is milk in the tank and therefore the washing cycle will not be initiated.

One possible controller program for use in the control system is given below. It should be appreciated that other controller programs may be used in accordance with the present invention. 253612 CONTROLLER PROGRAMME Steps 0. Electric power supply to chiller compressor turned off Wash Tub high level switch open 1. Tanker driver's control system start switch closed Wash Tub cold water valve opens Wash Tub low level switch closed ) Wash Tub fills Wash Tub high level switch closed ) with cold water Wash Tub cold water valve closes Compressor pressure sensor signals low - if not hold until low 15 Then Step Advance 2. Wash Pump starts Rinse Step 1 light on Wash Tub high level switch opens ) Wash Tub empties 20 Wash Tub low level switch opens ) cold water into milk tank Wash Pump stops Rinse Step 1 light off Then Step Advance 3. Detergent pump starts Detergent pump stops (after preset time) Then Step Advance 4. Wash Tub hot water valve opens Wash Tub low level switch closes ) Wash Tub fills Wash Tub high level switch closes ) with hot water Wash Tub hot water valve closes 9 536: 2 Then Step Advance Wash pump starts Wash Step 2 light on Wash Tub high level switch opens Wash Tub low level switch opens Wash Pump stops Wash Step 2 light off Then Step Advance Wash Tub empties hot water and detergent into milk tank Wash Tub cold water valve opens Wash Tub low level switch closes ) Wash Tub high level switch close ) Wash Tub cold water valve closes Wash Tub fills with cold water Then Step Advance Wash pump starts Rinse Step 3 light on Wash Tub high level switch opens ) Wash Tub low level switch opens ) Wash pump stops Rinse Step 3 light off Wash Tub empties cold water into milk tank Cycle complete Return to Step 0 - ready light on It can be seen from the above controller programme, that for the control 30 system to operate a next step in the wash cycle, all of the sensors must indicate that the system is in the normal expected operating mode. If not, the control system stops at that step and may in some instances activate an alarm signal. 6 ? 3 2 6! -2 If there is a short power cut, there may be memory means within the control system so that the washing system can start up from the last executed step once the power is restored. If for some reason the power is interrupted to the control system for a long period of time, then there may be incorporated 5 means to reset the washing cycle.

Extra safety features which may be incorporated are the provision of maximum times for each step, for instance cold water valve open for 20 minutes, wash pump operating for 10 minutes and hot water valve open for 60 minutes. If a maximum time is exceeded the program can perhaps stop the 10 washing cycle and/or activate an alarm.

Aspects of the present invention now will be discussed by way of example only with reference to the accompanying drawings in which: Figure 1: Illustrates the control box of one embodiment of the present invention, and Figure 2: Illustrates apparatus which can be used in conjunction with the present invention.

With respect to Figure 1 there is illustrated a control system generally indicated by arrow 1. Within the housing 2 of the control system 1 is a microprocessor control circuit (not shown). Situated on the front face of the housing 20 2 are detergent pumps 3 and 3a which are connected to two separate detergent supplies 4a and 4b (shown in Figure 2). In this embodiment the detergent pumps 3 and 3a are peristaltic pumps. 7 233612 Above the detergent pump 3 is a power on switch 4 and a detergent routine/alternative switch 5. The detergent switch 5 is used to activate the required detergent pump 3 or 3a. For instance, the farmer may wish to use an alternative detergent to remove fat or protein build-up which might have occurred within the milk tank 23. He can then switch the required detergent switch 5 and the control system 1 will automatically operate pump 3a to add an alternative detergent from supply 4b. This process usually only occurs once or twice per week.

Beside the detergent switch 5 are a number of indicator lamps 6, 7, 8, 9 and 10. Indicator lamp 6 indicates when power is being fed to the control system. Indicator lamp 7 lights up when all conditions are ready for the wash cycle to be activated. Indicator lamps 8, 9 and 10 indicate which step of the washing cycle is currently operating.

Figure 2 illustrates apparatus which maybe involved in a washing operation. A remote start switch 11 is connected to the control unit 1. Preferably the remote start switch 11 is situated in the vicinity of the dairy milk tank 23 so that the tanker driver can conveniently operate the switch 11 once the milk tank 23 has been emptied of milk. The wash tub 12 is situated on a stand 13 which also accommodates a spray pump 14. Within the wash tub 12 are two level sensors, a low level switch 15 and a high level switch 16. Outlets 17, 18, 19 and 26 from the detergent pump 3, cold water supply and the hot water supply and detergent pump 3a respectively are positioned above the wash tub 12.

The cold water supply is the standard supply found in the milking sheds and this is controlled by the control system 1 through a cold water valve 20. The 8 233612" cold water supply is also connected to a continuous hot water unit 21. The hot water unit 21 only operates when cold water is allowed into it via a hot water valve 22 which is also controlled by the control unit 1.

Situated near the top of the milk tank 23 is a spray ball 24 which is connected 5 by piping 25 to the spray pump 14. In a wash cycle of one particular embodiment, the control system 1 may check if the power supply to the chiller compressor is turned off. Only if the power supply is turned off will the control system 1 signal ready.

In the first step of the washing cycle the control system 1 checks that the 10 upper level sensor switch 16 is open signalling a less than full wash tub 12 and then opens valve 20 to allow cold water to pour from outlet 18 to fill the wash tub 12. Once the water within the wash tub 1 has reached the upper liquid level sensor 16, the control system 12 turns off the valve 20. Next the control system 1 operates the spray pump 14 which pumps the cold water 15 within the wash tub 12 through the tubing 25 and out into the milk tank 23 through the spray ball 24. Once the lower liquid level sensor 15 detects that there is no liquid left within the wash tub 12, the control system 1 turns off the spray pump 14.

In the next step of the cycle, the control system 1 operates the detergent pump 20 3 which pumps detergent from the detergent source 4a out through outlet 17 and into the wash tub 12. Next, the hot water valve 22 is opened by the control system 1 to allow cold water to enter the continuous hot water heater 21. Hot water emerges from the water heater 21 via the outlet 19 into the wash tub 12. Once the upper liquid level sensor 16 senses that the wash tub 12 is full, the 25 control system 1 turns off the valve 22 and operates the spray pump 14 to pump 9 the hot detergent water into the milk tank 23. The amount of detergent which enters the wash tub 12 is determined by a timer within the control system 1. The spray pump 14 is turned off once the liquid within the wash tank falls below the lower liquid sensor 15.

In the final washing cycle, the control system 1 opens the cold water valve 20 so water can flow from the outlet 18 into the wash tub 12. Once the liquid within the wash tub 12 reaches the upper liquid level sensor 16, the cold water valve 20 is turned off and the spray pump 14 is operated to pump cold water into the milk tank 23, rinsing it out.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions maybe made thereto without departing from the spirit or scope thereof.

Claims (9)

• ZJ3612 WHAT I CLAIM IS:

1. A controller to automatically control the operation of a milk tank and/or milking machine washing system including a wash tub with hot and cold water sources, a detergent reservoir and a pipe set to convey liquid between the wash tub and the tank and/or machine to be washed, characterised in that the controller controls the washing system in a multi-step washing cycle in which hot and/or cold water is repeatedly supplied to the wash tub from the hot and cold water sources and in which washing liquid is repeatedly conveyed from the wash tub to the tank and/or machine, in that the controller controls the metering of the detergent from the reservoir into the wash tub^ during a step of the washing cycle, and in that the controller automatically resets ready to control a further washing cycle once a washing cycle is completed.

2. A controller as claimed in claim 1 which controls a multi-step washing cycle including the steps of: a) filling the wash tub with cold water which is then used to wash out milk or residues in a milk tank and/or milking machine, and b) filling the wash tub with a hot water wash which is then used to wash a milk tank and/or washing machine to leave a sanitised surface.

3. A controller as claimed in claim 2 wherein the multi-step washing cycle controlled by the controller includes the step of providing a cold wash to rinse traces of detergent from a milk tank and/or milking machine. 1 >, * \ r-. 11 ,t"- ' rvt °j7 [7\ y

4. A controller as claimed in any one of claims 1 to 3 wherein the controller controls the operation of a cold water valve and a hot water valve of the hot and cold water sources.

5. A controller as claimed in any one of claims 1 to 4 wherein the controller \ receives feedback from liquid level sensors.

6. A controller as claimed in any one of claims 1 to 5 wherein the controller controls the metering of detergent into the wash tub by causing a pump to operate.

7. A controller as claimed in any one of claims 1 to 6 wherein the controller controls the operation of a spray ball to spray liquid used in the washing cycle into a milk tank and/or milking machine.

8. A controller as claimed in any one of claims 1 to 7 wherein the controller includes memory means so that the washing cycle can start from the last executed step if there has been an interruption in the power to the control Centre I\<j-3y3tcni.

9. A controller substantially as herein described with reference to and as illustrated by the accompanying drawings. IAN HENRY HEYES by his Attorneys 12