ZA200510156B - "Temperature monitoring" - Google Patents

Description

_ . :

THIS INVENTION relates to temperature monitoring. In particular the invention relates to a temperature monitor, to a temperature monitoring system and to a method of monitoring temperature of a container's interior during transport.

According to one aspect of the invention, there is provided a portable self- contained temperature monitor which includes an internal electrical power source; : at least one temperature sensor connected to the power source and operable to monitor temperature over a monitoring period of time; and a status indicator operable to display a predefined temperature event during the monitoring period.

The predefined temperature event may include monitoring a specific temperature, or monitoring a predefined temperature threshold being exceeded, monitoring a temperature within a predefined temperature range, or the like. In one embodiment the status indicator may indicate if a predefined minimum or maximum temperature threshold has been violated.

The monitor may include a recorder operatively connected to the sensor and the internal electrical power source for recording temperature values over at least a portion of the monitoring period.

The monitor may include a processor operatively connected to the sensor.

The monitor may also include a storage memory connected to the processor, the processor being operable to store or record monitored temperature values in the storage memory. In one embodiment of the invention, the storage memory is in the

CAMS Word\My Documents\Specs\Ambusave_cs /tic 13 December 2005 8:55 AM form of non-volatile solid state memory from which the processor may retrieve previously stored temperature values.

The status indicator may be in the form of an LED, operable fo indicate if a : 5 predefined temperature event occurred, e.g. by illuminating, or by illuminating in a particular colour depending on which type of temperature event occurred. In another embodiment, the status indicator may be in the form of an alphanumeric display, e.g. an

LCD display, for displaying information related to the temperature event.

The status indicator may instead include an audio transducer, an incandescent display, or a thermochromatic element, e.g. defined by a thermochromatic portion of a monitor enclosure. The status indicator may also comprise an LED digit numerical display, an LED digit alphanumeric display, an LED dot matrix display or an

LCD light bar display. :

The electrical power source may be in the form of a battery of electrochemical cells which may be rechargeable. The monitor may include a set of electrical terminals which are connectable to an external charger for recharging the rechargeable battery.

The electrical power source may instead include an electromechanical energy generator, a solar cell, a thermoelectric generator or a charge-holding capacitor.

At least one of the set of electrical terminals of the monitor may be connected to the temperature sensor for sensing the temperature via the electrical terminals, or the temperature sensor may be connected to a body of a monitor enclosure. The monitor may thus be hermetically sealed by means of a monitor enclosure.

The recorder may be controllable selectively to initiate recording of the monitored temperature values on the occurrence of a predefined event, e.g. after elapse of a predefined time period or if a threshold temperature value has been exceeded.

Also, by way of example, the recorder may be operable to initiate recording a predefined duration of time after the electrical terminals were disconnected from the

CAMS Word\My Documents\Specs\Ambusave_cs tic 13 December 2005 8:55 AM a charger for charging the rechargeable battery, allowing the monitor to be installed in a container and the temperature sensors to stabilize before recording.

The monitor may include more than one temperature sensor (i.e. a combination of temperature sensors). Each temperature sensor may be selected to sense a temperature only over its active- or accurate range. Thus in combination, the sensors sense the temperature accurately over the accurate ranges of the combination of the sensors. For example, two sensors may be used, one to sense temperature values above 0°C accurately and another to sense temperatures below 0°C accurately.

The temperature sensor(s) may include a solid state device or electronic sensor, a bimetal temperature sensor or thermocouple, a positive temperature coefficient resistance changing device, a negative temperature coefficient resistance changing device, an analogue or digital temperature responding device, or any combination of these. :

The monitor may include a voltage measurement circuit to measure the electrical power source voltage. The recorder may be operable also to record the voltage measurements. The monitor may be operable to measure and record the voltage immediately prior to each temperature measurement and recordal. The status indicator may also be operable to indicate if the battery voltage is outside predefined limits.

According to another aspect of the invention, there is provided a temperature monitoring system which includes a temperature monitor as hereinbefore described; and a processing unit operable to communicate with the monitor.

The temperature monitoring system may also include one or more of an external power source for the temperature monitor, a charging unit for charging a rechargeable battery of the temperature monitor, a communications unit, a global position system (GPS) unit or a global tracking unit. The communications unit may be operable to provide half or full duplex remote communication via radio frequency, line- of-sight laser communications, or satellite communications.

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The processing unit may be operable to communicate with the monitor to retrieve recorded temperature values from the monitor. The processing unit may also be operable to communicate with the monitor to store configuration parameters on the monitor. 5

The processing unit may be connectable to a display for displaying recorded temperature values. In one embodiment, the processing unit is connectable to a computer or other communications device for receiving and displaying recorded : temperature values. The processing unit may receive configuration parameters, such as the predefined events, the predefined activation delay, or the like from the computer.

The temperature monitoring system may thus include a computer which is operatively connected or connectable to the processing unit for downloading recorded temperature values.

The processing unit may include a charger and a matched set of terminals for connecting to the electrical terminals of the temperature monitor.

According to a further aspect of the invention, there is provided a method of monitoring temperature of a container’s interior during transport, the method inciuding placing a portable self-contained temperature monitor in the container to monitor the temperature of the interior of the container; activating the temperature monitor to monitor the temperature over a monitoring . period of time; and checking the temperature monitor on opening of the container for occurrence of a predefined temperature event during the monitoring period.

The predefined temperature event may include monitoring a specific temperature, monitoring a predefined temperature threshold being exceeded, or monitoring a temperature within a predefined temperature range, or the like.

The temperature monitor may be a temperature monitor as hereinbefore described.

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The invention will now be described, by way of example, with reference to the following diagrammatic drawings, in which:

Figure 1 shows a schematic block diagram of a temperature monitor in accordance with the invention;

Figure 2 shows a schematic block diagram of a processing unit for use in a temperature monitoring system, in accordance with the invention;

Figure 3 shows a flow diagram of the temperature monitor shown in Figure 1 in operation;

Figure 4 shows a flow diagram of the processing unit shown in Figure 2 in operation;

Figure 5 shows a flow diagram of a computer for use in a temperature monitoring system, in accordance with the invention, in operation; and

Figure 6 shows a three dimensional view of one embodiment of a temperature monitoring system in accordance with the invention.

In the drawings, reference numeral 10 refers to a temperature monitor in accordance with the invention. The temperature monitor 10 includes an internal power source in the form of a battery 12, a temperature sensor 14 and a status indicator in the form of a tight emitting diode (LED) 16. :

The temperature monitor 10 further includes a set of electrical terminals 18, connectable to an alternating current (AC) external power source, a diode rectifier 20 for rectifying the AC voltage received via the terminals 18 and a charger circuit 22 which includes a charging switch, for charging the battery 12.

The temperature monitor 10 also include a recorder comprising a processor 24 and a non-volatile solid state memory 26 operatively connected to the processor 24. ’

The processor 24 receives power from the battery 12 and is connected fo the temperature sensor 14, in operation to read temperature values from the sensor 14.

The sensor 14 is a solid state device with its electrical characteristics dependent on the temperature to which it is exposed.

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The monitor 10 also includes an accurate voltage reference 30, from which a voltage value can be read to correct inaccurate sensor readings caused by the voltage of the battery 12 dropping over the monitoring period.

The monitor 10 includes a communication port 28 for communicating to a processing unit 50 (shown in Figure 2). The communication port 28 includes a voltage pulse width demodulator 28.1 which is operable to demodulate voltage pulses received via the terminals 18 and a current pulse generator 28.2 to modulate current pulses on the terminals 18. In this example the set of terminals 18 includes only two terminals, hence information is received by means of voltage pulses and is transmitted by means of current pulses, the two types of pulses thus not interfering with each other and thus providing half duplex communication between the monitor 10 and the processing unit 50. It is to be appreciated that other types of communication protocols can be used that provide for full duplex communication between the monitor 10 and the processing unit 50.

The sensor 14 comprises two sensors (not shown) selected to sense temperatures accurately over a wide temperature range possibly exceeding the effective temperature sensing range of any one of the individual sensors.

Figure 2 shows the processing unit 50 which is part of a temperature monitoring system. The processing unit 50 includes a mains terminal 52 which is connectable to a mains power supply, protective circuitry 54 comprising a fuse and a switch (not shown), a voltage step- down transformer 56 and voltage conditioning circuitry in the form of a capacitor 58 and a voltage regulator 60. A backup battery 68 is also connected to the voltage regulator 60 to provide power in the event of a mains power failure.

The processing unit 50 includes also a processor 62, a communication interface circuit 64 and a communication terminal 66. The communication terminal 66 in this example is an RS232 terminal which is connectable to a computer (not shown).

The interface circuit 64 provides communication between the computer and the processing unit 50.

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A Current Limiting Circuit 72 is connected to the voltage regulator 60 and operable to regulate a charging current supplied to the temperature monitor 10 (see

Figure 1) via terminals 74.

A signal converting circuit 76 is operable to receive current pulses from the pulse generator 28.2 and to transmit pulse width modulated voltage pulses to the demodulator 28.1 via communication terminals 78. The Current Limiting Circuit 72 and a Current Limiting Circuit 77 both work on the same principle. A series sense resistor within the output circuit will generate a voltage across it that is proportional to the current flowing through the sense resistor. If the voltage across the sense resistor rises to exceed a predetermined limit, active electronic circuitry will reduce the output voltage to 74 thereby to limit the increase in current. In this fashion the output current is curtailed and limited.

The terminals 18 of the temperature monitor 10 are connectable either to terminals 74, allowing the battery 12 to be recharged, or are connectable to terminals 78 allowing the temperature monitor 10 and the processing unit 50 to communicate. The charging switch which is part of the charging circuit 22 of the temperature monitor 10 is operable selectively to provide for charging of the battery 12 or to provide for communication via the communications interface 28 of the temperature monitor 10, depending on which of the terminals 74 and 78 are connected to the terminal 18. Itis also to be appreciated that the terminals 74 and 78 may be one and the same.

In Figure 3, the operation of the temperature monitor 10 is described with reference to the flow diagram illustrating execution of a program running on the processor 24 of the temperature monitor 10. At 100 the temperature monitor is initialized, at 102 the charging circuit 22 performs a test to determine if the temperature monitor 10 is connected to terminals 74 or to terminals 78. If the temperature monitor 10 is connected to terminals 74 at 104 the battery 12 is tested and a charging sequence is initiated to charge the battery 12 of the temperature monitor 10. At 106 the processor 24 waits for a signal from the processing unit 50, upon which signal data is either received by the temperature monitor 10 via the communication interface 28 or information is transmitted to the processing unit 50, also via communications interface 28, at 108.

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If it is determined that the temperature monitor 10 is not connected to terminals 74 it is an indication that the temperature monitor 10 has been removed from the processing unit 50 and at 110 a timer sequence is initiated to activate recording by the processor 24 and memory 26 after a predefined delay. At 112 a battery check is initiated to check the voltage of the battery 12 and at 114 execution is directed to 116 if the battery voltage is below a certain threshold, which would cause the temperature monitor 10 to shut down whilst still maintaining the data previously stored in the non- volatile solid state memory 26. If the battery voltage is above a certain threshold at 118, the temperature monitoring function is scheduled by setting an interval timer which prompts the processor 24 to take a temperature reading by sampling the sensor 14 and to take a voltage reading by sampling the battery voltage 12. At 122 the temperature and voltage samples are stored in the memory 26 and at 124 the processor 24 halts execution until receiving an interrupt from the interrupt timer set up in 118.

The cycle comprising the actions in 112, 114, 118, 120, 122 and 124 will continue until the voltage of the battery 12 falls below a certain threshold and execution is directed at 114 to halt operation of the temperature monitor 10 at 116, or until 126 detects connection to the processing unit 50.

Referring to Figure 4, execution of the processor 62 of the processing unit 50 is illustrated in a flow diagram. The processing unit 50 is initialized at 130 and the current limiting circuit 72 and 77 is initialized at 132. At 134 the processor 62 waits for a signal from a computer (not shown) to which it is connected via terminals 66. At 136 a signal is transmitted via terminals 78, which signal is monitored and if no response is received on terminals 78 the processor 62 waits a predefined period of time at 138, after which execution returns to 134.

If a response is received on terminals 78 a confirmation signal is sent to the computer at 140 and at 142 a command from the computer is awaited. At 144 the command received from the computer at 142 is sent to the temperature monitor 10. In response, the command received from the temperature monitor 10 is sent to the computer at 146 and the steps 142, 144 and 146 are repeated until it is determined at 148 that the communication has terminated, after which the charging of the temperature monitor 10 is reactivated at 150.

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Referring to Figure 5, a flow diagram illustrates execution of a program on : the computer which is connected to the processing unit 50 via terminals 66. Execution of the program may be prompted by a user or it may be automatic. At 160 the computer is initialized and at 162 a signal is sent to the processing unit 50. At 164 it is determined whether a temperature monitor 10 is connected to a processing unit 50 and if not, the computer waits for a predefined period of time at 166 before returning execution to 162.

If a temperature monitor 10 is connected to a processing unit 50 as determined at 164, data is received by the computer at 168 from the memory 26 via the processing unit 50.

At 170 an indication is provided when all the data has been downloaded from the memory 26. At 172 the data downloaded from the memory 26 are saved onto the computer, which data can then be manipulated as required.

In Figure 6, a temperature monitoring system 200 in accordance with the invention is shown. The temperature monitoring system includes a number of temperature monitors 202 to 208, installed on a processing unit 210 which is connected to a computer 212. The processing unit 210 has two docking bays, a recharging bay 214 and a communication bay 216. The docking bays 214, 216 include electrically conductive rails and define terminals 74 and 78, explained in Figure 2.

Temperature monitors 204 to 208 are docked in the recharging bay 214 and the temperature monitor 202 is docked in the communication bay 216. LED's 202.1 to 208.1 are visible on the temperature monitors 202 to 208. in use, when a temperature monitor is placed in the communication bay 216, such as monitor 202, the monitored temperatures are retrieved from its memory via the processing unit 210 to the computer 212. The LED 202.1 on the monitor 202 flashes in an orange colour while data is retrieved from its memory.

When a monitor is placed in the charging bay 214 (where monitors 204 to 208 are shown) their batteries can be recharged. Initially, the recharging cycle is at a rate of approximately 50% of the batteries capacity, i.e. 0.030 amps and the LED will flash red at a 1Hz rate to indicate that it is recharging at a high rate. When the battery is nearly fully charged, the recharging cycle changes to a lower rate of approximately 5%

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.@ of the batteries capacity, i.e. 0.0030 amps and the LED will flash green at a 1Hz rate to indicate that it is nearly fully charged.

When the battery of a temperature monitor is fully charged and the temperature monitor is removed from the processing unit 210, the temperature monitor's timer is initiated (as described at 110 in Figure 3) before monitoring of temperature commences. The LED illuminates in periodic green flashes during the monitoring cycle.

The temperature monitor is pre-programmed with certain temperature thresholds depending on the products that are to be monitored. If a temperature threshold is violated, the LED colour will change from green to red for the periodic flash, providing a visual indication that the predefined temperature threshold has been violated.

The exact nature of the violation can then be analyzed by placing the temperature monitor into the communication bay 216, retrieving the monitored temperature values from the memory of the monitor and by displaying the monitored temperatures on a graph (not shown). In this example, the area of the graph where the monitored temperature was within the thresholds is displayed in green and the area where the monitored temperature violated the temperature thresholds is displayed in red. : The inventor believes that the invention, as illustrated, provides a new temperature monitor, a new temperature monitoring system and a new method of monitoring an interior temperature of a container during transport. In particular, the inventor believes that the invention, as illustrated, will be of particular use in combination with containers used to transport biological products, such as blood products, tissue samples, or the like, where the temperature during the transportation determines whether the products are fit for use, or not. In particular, the monitoring of the cold chain during transportation with a simple indication of the maintenance of the cold chain after transportation can reduce the wastage of biological products.

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Claims (19)

3 12 CLAIMS:

1. A portable self-contained temperature monitor which includes an internal electrical power source; at least one temperature sensor connected to the power source and operable to monitor temperature over a monitoring period of time; and a status indicator operable to display a predefined temperature event during the monitoring period.

2. The monitor as claimed in claim 1, which includes a recorder operatively connected to the sensor and the internal electrical power source for recording temperature values over at least a portion of the monitoring period.

3. The monitor as claimed in claim 2, which includes a processor operatively connected to the sensor, and a storage memory connected to the processor, the processor being operable to store or record monitored temperature values in the storage memory.

4, The monitor as claimed in claim 2 or claim 3, in which the recorder is controllable selectively to initiate recording of the monitored temperature values on the occurrence of a predefined event.

5. The monitor as claimed in any one of the preceding claims, in which the “electrical power source is in the form of a battery of rechargeable electrochemical cells, the monitor including a set of electrical terminals which are connectable to an external charger for recharging the rechargeable battery.

6. The monitor as claimed in any one of the preceding claims, which includes more than one temperature sensor (i.e. a combination of temperature sensors), each temperature sensor being selected to sense a temperature only over its active- or accurate range. CAMS Word\My Documents\Specs\Ambusave_cs /tjc 13 December 2005 8:55 AM

7. The monitor as claimed in any one of claims 2 to 4 inclusive, which includes a voltage measurement circuit to measure the electrical power source voltage, the recorder being operable also to record the voltage measurements.

8. A temperature monitoring system which includes a temperature monitor as claimed in any one of claims 1 to 7; and a processing unit operable to communicate with the monitor.

9. The temperature monitoring system as claimed in claim 8, in which the processing unit is operable to communicate with the monitor to retrieve recorded temperature values from the monitor.

10. The temperature monitoring system as claimed in claim 8 or claim 9, in which the processing unit is operable to communicate with the monitor to store configuration parameters on the monitor.

11. The temperature monitoring system as claimed in any one of claims 8 to 10 inclusive, in which the processing unit is connectable to a display for displaying recorded temperature values.

12. The temperature monitoring system as claimed in any one of claims 8 to 11 inclusive, in which the processing unit is connectable to a computer for receiving and displaying recorded temperature values.

13. A method of monitoring temperature of a container's interior during transport, the method including placing a portable self-contained temperature monitor in the container to monitor the temperature of the interior of the container; activating the temperature monitor to monitor the temperature over a monitoring period of time; and checking the temperature monitor on opening of the container for occurrence of a predefined temperature event during the monitoring period. C:AMS Word\My Documents\Specs\Ambusave_cs ftic 13 December 2005 8:55 AM

14. The method as claimed in claim 13, in which the predefined temperature event includes monitoring a specific temperature, monitoring a predefined temperature threshold being exceeded, or monitoring a temperature within a predefined temperature range.

15. The method as claimed in claim 13 or claim 14, in which the temperature monitor is a temperature monitor as claimed in any one of claims 1 to 7 inclusive.

16. A temperature monitor as claimed in claim 1, substantially as herein described and illustrated.

17. A temperature monitoring system as claimed in claim 8, substantially as herein described and illustrated.

18. A method of monitoring temperature of a container's interior as claimed in claim 13, substantially as herein described and illustrated.

19. A new temperature monitor, a new temperature monitoring system, or a new method of monitoring temperature, substantially as herein described. DATED THIS 13TH DAY OF DECEMBER 2005. , 7 S 7 A, - B 0% ADAMS & ADAMS APPLICANTS PATENT ATTORNEYS CAMS Word\My Documents\Specs\Ambusave_cs /tic 13 December 2005 8:55 AM