U.S. patent number RE36,200 [Application Number 08/647,002] was granted by the patent office on 1999-04-27 for disposable electronic monitor device.
This patent grant is currently assigned to Sensitech Inc.. Invention is credited to Donald W. Berrian, Peter M. Nunes, Ernest M. Santin, William A. Tout, John W. Vanderpot.
United States Patent |
RE36,200 |
Berrian , et al. |
April 27, 1999 |
**Please see images for:
( Reexamination Certificate ) ** |
Disposable electronic monitor device
Abstract
Apparatus for monitoring an externally applied parameter to
selected products. The invention involves a housing enclosing a
sensor, and a monitoring and output network. The sensor has a
characteristic that varies in some predetermined manner with
variation in the monitored parameter. The monitoring and output
network involves a sensor which produces a signal representative of
the monitored characteristic. Values associated with the signal are
stored in a memory device for subsequent, selected retrieval.
Inventors: |
Berrian; Donald W. (Topsfield,
MA), Santin; Ernest M. (Beverly, MA), Tout; William
A. (North Andover, MA), Nunes; Peter M. (Newburyport,
MA), Vanderpot; John W. (Rockport, MA) |
Assignee: |
Sensitech Inc. (Beverly,
MA)
|
Family
ID: |
25114362 |
Appl.
No.: |
08/647,002 |
Filed: |
May 9, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
778777 |
Oct 18, 1991 |
05313848 |
May 24, 1994 |
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Current U.S.
Class: |
73/866.2;
374/102; 73/492; 374/103; 374/108; 374/170; 702/104; 374/104 |
Current CPC
Class: |
G01D
1/04 (20130101); G01D 9/005 (20130101); G01K
1/022 (20130101); G01D 1/12 (20130101); G01D
1/14 (20130101) |
Current International
Class: |
G01K
1/02 (20060101); G01K 1/00 (20060101); G01D
9/00 (20060101); G01D 001/00 (); G01D 001/04 ();
G01D 001/10 (); G01K 007/00 () |
Field of
Search: |
;73/866.1,866.3,866.2,753,335.02,492,503,514.35
;374/102,103,104,108,170 ;364/556,557,558,571.01-571.08 ;340/870.04
;702/104 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2 232 948 |
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Jan 1974 |
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DE |
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61-259130 |
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Nov 1986 |
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JP |
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2 045 480 |
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Oct 1980 |
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GB |
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2 058 357 |
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Apr 1981 |
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GB |
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2 079 951 |
|
Jan 1982 |
|
GB |
|
267 |
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Jan 1987 |
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WO |
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Other References
"Datatrace Temp.RTM., Temperature Environment Measurement System,
Micropack.TM.", product specification, Datatrace.RTM. (Division of
Mesa Medical, Inc.) Printed in USA Sep. 1990, 2 pages. .
"Datatrace Temp.RTM., Temperature Environment Measurement System,
Interface System" product specification, Datatrace.RTM. (Division
of Mesa Medical, Inc.) Printed in USA Sep. 1990, 2 pages. .
"Hamster.RTM." product specification, publication date unknown (but
prior to Feb., 1992), 2 pages. .
"The Reliable Ryans", Ryan Instruments, various advertising/price
brochures, publication dates Mar. 1990, 17 pages. .
"3M Announces . . . The Fusion of Time and Temperature", product
brochure, published by Nov. 1, 1989, 14 pages. .
"Freshness Control . . . From Plant to Plate--Lifelines", various
product brochures, LifeLines Technology, Inc., published 1989, 12
pages. .
"Datatrace Micropack" product specification, publication date
unknown but by Feb. 1992, 2 pages. .
"Datatrace PC Interface System" product specification, publication
date unknown but by Feb. 1992, 2 pages..
|
Primary Examiner: Noland; Thomas P.
Attorney, Agent or Firm: Lappin & Kusmer LLP
Claims
What is claimed is:
1. Apparatus for monitoring an externally applied parameter,
comprising
a housing enclosing:
A. a sensor having a characteristic that varies in a predetermined
manner with variation of said parameter;
B. a monitoring and output network including:
i. means coupled to said sensor for generating a signal
representative of variations of said characteristic over time,
ii. first storage means for storing values associated with selected
portions of said signal, said selected portions including other
than the most recent portion of said signal, and
iii. selectively operative means for generating an output signal
representative of selected ones of said stored values; and
C. a power supply in operable communication with said sensor and
said network.
2. Apparatus according to claim 1 wherein said parameter is
selected from the group consisting of temperature, pressure,
humidity, and acceleration.
3. Apparatus according to claim 1 wherein said monitoring and
output network is an integrated circuit.
4. Apparatus according to claim 1 wherein said first storage means
includes means for generating and storing at least one of the group
consisting of:
A. the value of said signal representative of the maximum value of
said characteristic and the time of generation of said value;
B. the value representative of the minimum value of said
characteristic and the time of generation of said value;
C. the value corresponding to the time integral of said
characteristic .[.beyond.]. .Iadd.outside of an acceptable range or
above or below .Iaddend.a predetermined threshold value;
D. the time that the value of said signal first exceeded a
predetermined threshold value;
E. the time that the value of said signal most recently exceeded a
predetermined threshold value;
F. the time that the value of said signal first fell below a
predetermined threshold value; and
G. the time that the value of said signal most recently fell below
a predetermined threshold value, and
H. the number of excursions .[.beyond.]. .Iadd.outside of an
acceptable range or above or below .Iaddend.a predetermined
threshold value.Iadd., and
I. the value corresponding to the cumulative time of said
characteristic outside of an acceptable range or above or below a
predetermined threshold value.Iaddend..
5. Apparatus according to claim 4 wherein said parameter is
selected from the group consisting of temperature, pressure,
humidity, and acceleration.
6. Apparatus according to claim 4 wherein said monitoring and
output network is an integrated circuit.
7. Apparatus according to claim .[.6.]. .Iadd.8 .Iaddend.wherein
said .Iadd.coded .Iaddend.output signal .[.coding.]. is binary.
8. Apparatus according to claim 4 wherein said output means
includes an optical signal generator for generating said optical
signal, said output signal being visually perceptible and being
coded to be representative of said selected ones of said stored
values.
9. Apparatus according to claim 1 further comprising selectively
operative means for interrogating said monitoring and output
network and for generating data representative of selected ones of
said stored values.
10. Apparatus according to claim 1 further comprising:
remotely adjustable second storing means for storing predetermined
comparative values, and
means for comparing said stored values of said signal with said
comparative values, said comparing means including means for
generating a signal representative of any discrepancy between said
stored values from said first storage means and said comparative
values of said second storage means.
11. Apparatus according to claim 1 wherein said output means
includes an optical signal generator for generating said output
signal, said output signal being visually perceptible and being
coded to be representative of said selected ones of said stored
values.
12. Apparatus according to claim 11 wherein said .Iadd.coded
.Iaddend.output signal .[.coding.]. is binary. .Iadd.
13. Apparatus according to claim 4 wherein said output signal is
representative of a first binary state if no excursions of said
characteristic outside of an acceptable range or above or below a
predetermined threshold value have occurred, and wherein said
output signal is representative of a second binary state if at
least one excursion of said characteristic outside of an acceptable
range or above or below said threshold value has
occurred..Iaddend..Iadd.14. Apparatus according to claim 4 wherein
said first storage means includes means for generating and storing
the value of said signal representative of the maximum value of
said characteristic and the time of generation of said
value..Iaddend..Iadd.15. Apparatus according to claim 4 wherein
said first storage means includes means for generating and storing
the value representative of the minimum value of said
characteristic and the time of
generation of said value..Iaddend..Iadd.16. Apparatus according to
claim 4 wherein said first storage means includes means for
generating and storing the value corresponding to the time integral
of said characteristic outside of an acceptable range or above or
below a predetermined threshold value..Iaddend..Iadd.17. Apparatus
according to claim 4 wherein said first storage means includes
means for generating and storing the time that the value of said
signal first exceeded a predetermined threshold
value..Iaddend..Iadd.18. Apparatus according to claim 4 wherein
said first storage means includes means for generating and storing
the time that the value of said signal most recently exceeded a
predetermined threshold value..Iaddend..Iadd.19. Apparatus
according to claim 4 wherein said first storage means includes
means for generating and storing the time that the value of said
signal first fell below a predetermined threshold
value..Iaddend..Iadd.20. Apparatus according to claim 4 wherein
said first storage means includes means for generating and storing
the time that the value of said signal most recently fell below a
predetermined threshold value..Iaddend..Iadd.21. Apparatus
according to claim 4 wherein said first storage means includes
means for generating and storing the number of excursions outside
of an acceptable range or above or below a predetermined threshold
value..Iaddend..Iadd.22. Apparatus according to claim 4 wherein
said first storage means includes means for generating and storing
the value corresponding to the cumulative time of said
characteristic outside of an acceptable range or above or below a
predetermined threshold value..Iaddend..Iadd.23. Apparatus
according to claim 1 wherein said monitoring and output network is
programmed to operate in:
a) a sleep mode, wherein a predetermined range of allowed values of
temperature is established,
b) a monitor mode, wherein the measuring and processing functions
are activated, and
c) a stop mode, wherein the measuring and processing functions are
irreversibly stopped,
wherein said monitoring and output network further comprises
independently actuatable start and stop devices for indicating a
change in the mode of operation..Iaddend..Iadd.24. Apparatus for
monitoring an externally applied parameter comprising:
a housing enclosing:
A. a sensor having a characteristic that varies in a predetermined
manner with variation of said parameter,
B. a monitoring and output network including:
i. means coupled to said sensor for generating a signal
representative of variations of said characteristic over time,
ii. first storage means for storing values associated with selected
portions of said signal, said selected portions including other
than the most recent portion of said signal, and
iii. selectively operative means for generating an output signal
representative of selected ones of said stored values; and
C. a power supply in operable communication with said sensor and
said network,
wherein said first storage means includes means for generating and
storing at least one of the group consisting of:
A. the value of said signal representative of the maximum value of
said characteristic and the time of generation of said value;
B. the value representative of the minimum value of said
characteristic and the time of generation of said value;
C. the value corresponding to the time integral of said
characteristic outside of an acceptable range or above or below a
predetermined threshold value;
D. the time that the value of said signal first exceeded a
predetermined threshold value;
E. the time that the value of said signal most recently exceeded a
predetermined threshold value;
F. the time that the value of said signal first fell below a
predetermined threshold value;
G. the time that the value of said signal most recently fell below
a predetermined threshold value;
H. the number of excursions outside of an acceptable range or above
or below a predetermined threshold value; and
I. the value corresponding to the cumulative time of said
characteristic outside of an acceptable range or above or below a
predetermined threshold
value..Iaddend..Iadd.25. Apparatus according to claim 24 wherein
said parameter is selected from the group consisting of
temperature, pressure, humidity and acceleration..Iaddend..Iadd.26.
Apparatus according to claim 24 wherein said monitoring and output
network is an integrated circuit..Iaddend..Iadd.27. Apparatus
according to claim 24 wherein said output means includes an optical
signal generator for generating said output signal, said output
signal being visually perceptible and being coded to be
representative of said selected ones of said stored
values..Iaddend..Iadd.28. Apparatus according to claim 27 wherein
said coded output signal is binary..Iaddend..Iadd.29. Apparatus
according to claim 24 further comprising selectively operative
means for interrogating said monitoring and output network and for
generating data representative of selected ones of said stored
values..Iaddend..Iadd.30. Apparatus according to claim 24 further
comprising remotely adjustable second storing means for storing
predetermined comparative values, and means for comparing said
stored values of said signal with said comparative values, said
comparing means including means for generating a signal
representative of any discrepancy between said stored values from
said first storage means and said comparative values of said second
storage
means..Iaddend..Iadd.31. Apparatus according to claim 28 wherein
said output signal is representative of a first binary state if no
excursions of said characteristic outside of an acceptable range or
above or below a predetermined threshold value have occurred, and
wherein said output signal is representative of a second binary
state if at least one excursion of said characteristic outside of
an acceptable range or above or below a predetermined threshold
value has occurred..Iaddend..Iadd.32. Apparatus according to claim
24 wherein said monitoring and output network is programmed to
operate in:
a) a sleep mode, wherein a predetermined range of allowed values of
temperature is established,
b) a monitor mode, wherein the measuring and processing functions
are activated, and
c) a stop mode, wherein the measuring and processing functions are
irreversibly stopped,
wherein said monitoring and output network further comprises
independently actuatable start and stop devices for indicating a
change in the mode of operation..Iaddend..Iadd.33. Apparatus
according to claim 24 wherein said first storage means includes
means for generating and storing the value of said signal
representative of the maximum value of said characteristic and the
time of generation of said value..Iaddend..Iadd.34. Apparatus
according to claim 24 wherein said first storage means includes
means for generating and storing the value representative of the
minimum value of said characteristic and the time of generation of
said value..Iaddend..Iadd.35. Apparatus according to claim 24
wherein said first storage means includes means for generating and
storing the value corresponding to the time integral of said
characteristic outside of an acceptable range or above or below a
predetermined threshold
value..Iaddend..Iadd.36. Apparatus according to claim 24 wherein
said first storage means includes means for generating and storing
the time that the value of said signal first exceeded a
predetermined threshold value..Iaddend..Iadd.37. Apparatus
according to claim 24 wherein said first storage means includes
means for generating and storing the time that the value of said
signal most recently exceeded a predetermined threshold
value..Iaddend..Iadd.38. Apparatus according to claim 24 wherein
said first storage means includes means for generating and storing
the time that the value of said signal first fell below a
predetermined threshold value..Iaddend..Iadd.39. Apparatus
according to claim 24 wherein said first storage means includes
means for generating and storing the time that the value of said
signal most recently fell below a predetermined threshold
value..Iaddend..Iadd.40. Apparatus according to claim 24 wherein
said first storage means includes means for generating and storing
the number of excursions outside of an acceptable range or above or
below a predetermined threshold value..Iaddend..Iadd.41. Apparatus
according to claim 24 wherein said first storage means includes
means for generating and storing the value corresponding to the
cumulative time of said characteristic outside of an acceptable
range or above or below a predetermined threshold
value..Iaddend..Iadd.42. Apparatus for monitoring an externally
applied parameter comprising
a housing enclosing:
A. a sensor having a characteristic that varies in a predetermined
manner with variation of said parameter;
B. a monitoring and output network including:
i. means coupled to said sensor for generating a signal
representative of variations of said characteristic over time,
ii. first storage means for storing values associated with selected
portions of said signal, said selected portions including other
than the most recent portion of said signal, and
iii. selectively operative means for generating an output signal
representative of selected ones of said stored values; and
C. a power supply in operable communication with said sensor and
said network,
wherein said output signal is representative of a first binary
state if no excursions of said characteristic outside of an
acceptable range or above or below a predetermined threshold value
have occurred, and wherein said output signal is representative of
a second binary state if at least one excursion of said
characteristic outside of an acceptable range or above or below a
predetermined threshold value has occurred..Iaddend..Iadd.43.
Apparatus according to claim 42 wherein said first storage means
includes means for generating and storing the value of said signal
representative of the maximum value of said characteristic and the
time of generation of said value..Iaddend..Iadd.44. Apparatus
according to claim 42 wherein said first storage means includes
means for generating and storing the value representative of the
minimum value of said characteristic and the time of generation of
said value..Iaddend..Iadd.45. Apparatus according to claim 42
wherein said first storage means includes means for generating and
storing the value corresponding to the time integral of said
characteristic outside of an acceptable range or above or below a
predetermined threshold value..Iaddend..Iadd.46. Apparatus
according to claim 42 wherein said first storage means includes
means for generating and storing the time that the value of said
signal first exceeded a predetermined threshold
value..Iaddend..Iadd.47. Apparatus according to claim 42 wherein
said first storage means includes means for generating and storing
the time that the value of said signal most recently exceeded a
predetermined threshold value..Iaddend..Iadd.48. Apparatus
according to claim 42 wherein said first storage means includes
means for generating and storing the time that the value of said
signal first fell below a predetermined threshold
value..Iaddend..Iadd.49. Apparatus according to claim 42 wherein
said first storage means includes means for generating and storing
the time that the value of said signal most recently fell below a
predetermined threshold value..Iaddend..Iadd.50. Apparatus
according to claim 42 wherein said first storage means includes
means for generating and storing the number of excursions outside
of an acceptable range or above or below a predetermined threshold
value..Iaddend..Iadd.51. Apparatus according to claim 42 wherein
said first storage means includes means for generating and storing
the value corresponding to the cumulative time of said
characteristic outside of an acceptable range or above or below a
predetermined threshold value..Iaddend..Iadd.52. Apparatus
according to claim 42 further comprising:
remotely adjustable second storing means for storing predetermined
comparative values, and means for comparing said stored values of
said signal with said comparative values, said comparing means
including means for generating a signal representative of any
discrepancy between said stored values from said first storage
means and said comparative values of said second storage
means..Iaddend..Iadd.53. Apparatus according to claim 42 wherein
said monitoring and output network is programmed to operate in:
a) a sleep mode, wherein a predetermined range of allowed values of
temperature is established,
b) a monitor mode, wherein the measuring and processing functions
are activated, and
c) a stop mode, wherein the measuring and processing functions are
irreversibly stopped,
wherein said monitoring and output network further comprises
independently actuatable start and stop devices for indicating a
change in the mode of operation..Iaddend.
Description
BACKGROUND OF THE INVENTION
The present invention relates to electronic monitor devices
intended for disposable use in packaging. Such devices may monitor
temperature, humidity, pressure, acceleration, and other parameters
which may affect transported goods.
Temperature monitors are important in any industry involving
products that are temperature sensitive. This includes such broad
categories as food and beverages, medical and pharmaceuticals,
biologicals, and industrial chemicals and adhesives. In addition to
producers within these industries, monitoring the environment of
products is important to distributors, suppliers, storage
facilities, and large service providers such as hospitals, the
military, and large restaurant chains.
Within each of these industries there are a variety of reasons for
using an environment monitoring device. For example, such monitors
may be used as an aid in controlling product quality, to monitor
the performance of shippers, to minimize product loss due to
temperature exposure, and to aid in identifying responsible parties
in instances of product loss. It is known that substantial amounts
of fresh produce are lost each year in the transportation phase of
distribution, largely due to temperature variations during
transport.
While temperature is a significant cause of damage to transported
goods, it is not the only cause of damage. Other identified causes
include improperly stacked boxes resulting in shock to the
packaging, improper packaging materials leading to shatter, product
damage during loading, and moisture loss. Improper handling often
leads to in-transit vibration which may aggravate problems started
at the packing house. It may be important, in a given field, to
monitor any one or all of these factors to control shipping loss to
goods.
Over the years, commercially available products have been developed
to monitor temperature for transportation of goods. These products
often include strip recorders that produce hard copy output. The
classic strip recorder recorded temperature on a revolving drum,
the speed of which could be altered depending upon the amount of
time that needed to be recorded. Modern strip recorders are more
likely to be digital and will store the information as it is
recorded for later retrieval. For those devices, a specialized
reader or a computer with a graphics capability printer is required
to read out the recorded information. One commercially available
product incorporating such a strip recorder is manufactured by Ryan
Instruments, Redmond, Wash.
The Ryan monitors are relatively large, and are intended to be
installed either in the environment of a transportation vehicle, or
in large containers containing the temperature-sensitive goods. The
Ryan monitors record temperatures in memory, and the recorded
information is accessible by an external access device, such as a
computer, by printout using a bimetal coil recorder, or by visual
LCD display. Various models of Ryan monitors test for humidity,
with similar forms of data output.
Control One, Inc., Stamford, Conn., manufactures a line of time and
temperature monitors. These devices have internal recorders
utilizing stainless steel or Teflon probes. Temperature readings
may be taken as often as every four seconds, or as infrequently as
once every 72 hours. These devices are generally housed in a closed
housing unit which can be selectively turned on and off. In many
shipping situations it is undesirable to enable the user to turn
off an activated system, since it would facilitate fraudulent
readings.
Both the Ryan and the Control One devices are pre-programmed by the
manufacturer to read a broad range of temperatures, or an end-user
specified range. Both manufacture devices which may be coupled to
an external printing device, and some must be returned to the
manufacturer for a secure parameter reading.
A third type of device is manufactured by 3M, St. Paul, Minn. These
"product exposure indicators" give visual signals of temperature
exposure. The devices are generally in the form of tags and labels
which record the cumulative exposure time spent over certain
temperatures. These indicators function by means of an irreversible
physical change. If exposure occurs beyond a specific temperature
level, these indicators detect and record the extended temperature
elevation.
In an exemplary 3M device, each tag has a temperature set point,
and visually indicates the temperature change by color change or
indicator movement. Each tag has a series of viewing windows on the
top surface, protected by a clear film overlay. When the activation
temperature of the tag is exceeded, e.g., above 10.degree. C., a
blue color appears in a window, and gradually moves across the tag
windows with time. Movement of the color indicator is halted if
temperature falls below the set point, and resumes again with
temperature rise. The location of coloration shown through the
viewing windows is a function of time and temperature. That is, a
short period of exposure at a relatively high temperature will
result in coloration comparable to a longer period of exposure at a
lower temperature.
These types of devices do not enable long-term parameter monitoring
against user-determined preselected parameters. It is important
that the monitoring device be tamper-resistant, to prevent
manipulation of the recorded readings. It is also desirable that
the end-user be able immediately to take a reading of any
temperature fluctuation. Cumulative measurements are not as useful
as discrete event detection for those situations when short-term
exposure to extreme temperatures is detrimental to the goods, such
as pharmaceuticals or other biological materials.
Accordingly it is an object of the present invention to provide a
relatively accurate, dynamic and inexpensive way to monitor the
temperatures to which products are subjected during shipment.
SUMMARY OF THE INVENTION
The present invention generally relates to apparatus for monitoring
an externally applied parameter, such as temperature, to selected
products.
More specifically, the invention involves a housing enclosing a
sensor, and a monitoring and output network. The sensor has a
characteristic that varies in some predetermined manner with
variation in the monitored parameter. For example, if the parameter
to be measured is temperature, the sensor has a characteristic that
varies in response to changes in temperature. Alternatively, the
sensor may have a characteristic that varies with such parameters
as pressure, acceleration, and humidity.
The monitoring and output network involves a sensor which produces
a signal representative of the monitored characteristic. Values
associated with the signal, e.g., actual temperature values, are
stored in a memory device for subsequent, selected retrieval. The
values may be retrieved by means of a read-out device selectively
coupled to the monitor apparatus, or may be displayed on a visual
display device. The network may be an integrated circuit, and is
adapted to monitor the output of the sensor.
The apparatus may store several different values. For example, one
value may represent a combination of the maximum value for a
selected characteristic, together with the time that value was
achieved. Another value may represent the minimum value for the
selected characteristic, together with the time at which that value
was reached. Another value may correspond to the time integral of
the selected characteristic above or below a predetermined
threshold value. Time measurements may include: the time that the
particular value of a signal first exceeded a predetermined
threshold value; the time that the value of the signal most
recently exceeded a predetermined threshold value; the time that
the value of the signal first fell below a predetermined threshold
value; and/or the time that the value of the signal most recently
fell below a predetermined threshold value.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other advantages of the present invention will be more
fully understood by reference to the following detailed description
in conjunction with the attached drawings in which:
FIG. 1 is a perspective view of a temperature monitoring device
embodying the present invention;
FIG. 2 shows in block diagram form the circuit of the embodiment of
FIG. 1;
FIG. 3 is a top elevation view of an interrogation device for the
monitoring device of FIG. 1;
FIG. 3A is a sectional view of the interrogation device of FIG. 3;
and
FIG. 4 is a graph illustrating the various temperature parameters
that may be monitored using an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention generally is a programmable electronic
monitor device for measuring selected parameters, such as ambient
temperature, and humidity. While the illustrated, preferred
embodiment is described below in terms of a temperature monitor,
equivalent devices for measuring other parameters such as pressure,
humidity, and acceleration, are contemplated as falling within the
scope of this disclosure.
Generally, the device monitors preselected parameters associated
with transportation and/or storage of goods. The values obtained
for the parameters are internally compared against a predetermined
set of threshold values. Identified instances of inconsistency or
consistency between the threshold values and actual measurements
are reported. Parameters and values may be stored in a memory
device for subsequent interrogation by the end-user.
In one embodiment where the monitored parameter is temperature, the
device compares temperatures encountered in storage or transit, to
a previously established range of acceptable values. The device may
then store selected data, such as data representative of (1) the
occurrence of excursions outside of the acceptable range, (2) times
of occurrence of the first cross-over and last cross-over from
acceptable values to overage and/or underage (measured with respect
to the acceptable value range) for excursions outside the
acceptable range, (3) times of occurrence of and magnitude of the
extreme values during excursions outside the acceptable range, and
(4) the number of out-of-range excursions. Generally, the stored
information may be retrieved in two ways: 1) visual display upon
user-activation of a display device; or 2) down-loading to an
external computer device.
A preferred embodiment of the present invention is shown in FIG. 1.
In that illustrated embodiment, the device 10 includes a housing
element 12. The housing element 12 encloses an internal thermistor
14 and associated circuit 14a (both shown in FIG. 2) and an optical
port 18, such as a pair of light emitting diodes (LED's), LED1
(RED) and LED2 (GREEN). In the illustrated embodiment of FIG. 1,
the device 10 includes data output control switch 16, which is
adapted to initiate a data output operation. In the illustrated
embodiment, the optical port 18 and output control switch 16 are
mechanically keyed to interface with an output device 50 (shown in
FIG. 3). The output device 50 may be a computer, a printer, or a
specially-adapted device for receiving input from the device 10
through port 18 upon activation of switch 16.
The housing element 12 of illustrated device 10 is preferably
manufactured using acrylonitrile butadiene-styrene (ABS) that is
formed into the desired shape using conventional molding methods.
The shape of the housing element may be round, oval, or any other
geometric configuration. The illustrated housing element has a
diameter of approximately 2.5 inches, a height of approximately
0.625 inches, and a weight of approximately 42 grams. However, the
housing element may have different dimensions, depending upon the
size of the individual components contained within. A pair of
electrically insulating flexible pull-strips 40 and 42 extend from
slits in the sidewall of housing 12.
The internal thermistor is thermally coupled to the external
environment-to-be-monitored, and consists of any material, such as
a semiconductor material which is reactive to changes in the
designated parameter, such as temperature. Alternatively, devices
selectively sensitive to other parameters, such as shock, humidity,
or ambient pressure, may be used.
The device 10 further may include an indicator test button 20 to
initiate a visual read-out at the port 18 indicative of whether the
device 10 is operative at any point in time without disrupting the
monitoring function of the device. Alternatively, a separate
blinking LED may be used to indicate the operative state of the
device. Other features may be added to the device to augment
monitoring activities or read-out capabilities. These additional
auxiliary features are contemplated as being within the scope of
the present invention.
FIG. 2 shows thermistor 14 and circuit 14a for device 10. The
circuit 14a is a microprocessor-controlled network that is coupled
between thermistor 14 and the optical port 18. Circuit 14a includes
an analog-to-digital converter 30 coupled in series between
thermistor 14 and a microprocessor 32 and associated memory
(storage) device 34. A start device 36 and a stop device 38 are
coupled by way of a START signal line 36a and a STOP signal line
38a, respectively, to the microprocessor 32. The microprocessor 32
is coupled to optical port 18 by way of input/output (I/O) bus 39.
Preferably, the circuit 14a is a single integrated circuit,
permitting a low cost, compact, and low power implementation. In
such embodiments, the device 10 may be operated over relatively
long periods of time under battery power, yet still be sufficiently
low cost to be considered "disposable", especially compared with
prior art monitoring devices.
In the preferred embodiment, the microprocessor 32 is programmed to
operate in three modes: (1) sleep mode, (2) monitor mode and (3)
stop mode. In the sleep mode, the device 10 is programmed to
establish a predetermined range of allowed values of temperature
(thereby inherently defining a non-allowed range). In this mode,
relatively low power is drawn from the battery to keep the
programmed device ready for operation in the monitor mode.
In the monitor mode, the measuring and processing functions of
circuit 14a are activated, so that the device 10 actively monitors
temperature and then determines and store the temperature data
relating to environment of device 10. In the stop mode, the
measurement and processing functions are irreversibly stopped, and
the device 10 is maintained in a low power consumption mode, and is
adapted for externally triggered read-out of the stored data from
memory 34.
The start device 36 and stop device 38 are each coupled to input
lines of the microprocessor 32. Devices 36 and 38 are independently
actuable by a user to signal a desired change in the mode of
operation of the device 10. In the illustrated embodiment, each of
devices 36 and 38 includes an electrically insulating "pull-strip"
(pull-strip 40 for device 36 and pull-strip 42 for device 38)
positioned between a terminal 36b at an end of the START signal
line 36a and a ground connection for device 36 and a terminal 38b
at the end of the STOP signal line 38a and a ground connection for
device 38. The distal ends of pull-strips extend through associated
slots in the sidewall of housing 12. Terminals 36b and 38b are both
spring biased against their respective ground connection so that
the respective one of insulating pull-strips 40 and 42 may be
removed from device 10, thereby establishing a ground potential at
the respective one of lines 36a and 38a. The microprocessor 32 is
programmed so that when pull-strip 40 is removed from start device
36, then device 10 transitions from its sleep mode to its monitor
mode, and when pull-strip 42 is removed from stop device 38, then
device 10 transitions from the monitor mode to the stop mode. In
this configuration, an economical, tamper-resistant temperature
monitoring device is provided.
The optical port 18 may be selectively operative to enable a user
to obtain a visual indication of certain selected conditions. For
example, in the illustrated embodiment, the optical port 18
consists of a red LED and a green LED, LED1 (RED) and LED2 (GREEN).
These LED's are operatively coupled to a data switch 16 which, when
depressed, signals (via line 16a) microprocessor 32 that a data
interrogation operation is to be initiated in response to that
signal.
If there has been no out-of-range excursion since device 10 has
been activated in its monitor mode (as described below), then
microprocessor 32 causes the green LED2 to be illuminated in a
coded manner to generate an optical signal representative of the
stored data from memory 34 which is indicative of the highest and
lowest temperatures (and times of occurrence) since activation.
If there has been at least one out-of-range excursion since
activation, microprocessor 32 causes red LED1 to be illuminated in
a coded manner to generate an optical signal representative of the
stored data from memory 34 indicative of out-of-range related data,
as described below.
Thus, with the invention, device 10 included an optical port that
provides optical data that (1) may be interpreted visually by a
user (to decide if no out-of-range excursions have occurred (green)
or to decide if there were such excursions (red) and (2) may be
down-loaded to a computer to give specific characteristics of the
monitored temperature.
.Iadd.The output means includes an optical signal generator for
generating the output signal, which is visually perceptible and
coded to be representative of selected ones of the stored values.
The coded output signal is preferably binary. .Iaddend.
FIG. 3 shows a read-out device 50 that is adapted to down-load (or
read out) stored data from device 10. Read-out device 50 includes
an interface region 50A that has a surface that is substantially
complimentary to the upper surface of device 10. A pair of
photoreceptors 52 and 54 and an outwardly protruding extension
member 56 are positioned in region 50A with a geometrical layout
corresponding to that of LED1, LED2, and data switch 16. With that
configuration, the device 10 may be placed so that the
complementary regions of devices 10 and 50 are adjacent and the
photoreceptors 52 and 54 are aligned with LED1 and LED2,
respectively, of optical port 18, and so that the extension member
56 is adjacent to and depresses data switch 16. Device 50 includes
a microprocessor controlled circuit (indicated by reference
designation 62a in FIG. 3) that is adapted to receive the optical
signals generated by LED1 and LED2 and to process that data in a
manner desired by a user, for example, print out that data in hard
copy form. The device 50 may in some embodiments be configured as
an interface to a conventional programmed digital computer.
In the illustrated embodiment, the thermistor 14 receives a signal
from the environment representative of a change in temperature. The
thermistor 14 communicates the change to the circuit 14a, which
circuit includes a memory device 34 for storing preselected
parameters, and for storing the temperature change detected by the
thermistor 14.
The device 10 may be preferably programmed to compare actual
parameter readings against pre-programmed parameters. FIG. 4 shows
exemplary output data which may be stored in memory of the device
10 for subsequent retrieval. In FIG. 4, a graph of temperature
versus time is shown with respect to an allowed range of
temperatures between an upper limit and a lower limit. Point A on
the graph defines the time T1 that a first over-temperature reading
occurred. Point B defines both the peak temperature experienced by
the device and the time T2 that the peak temperature occurred.
Point C defines the time T3 that a last over-temperature event
occurred, and the area D under the curve and above the upper limit
represents the time integral of over-temperature for the excursion
between T1 and T3. In cases where a succession of over-temperature
excursions occur, the cumulative time integral of the
over-temperature excursions is stored. These measurements are made
relative to the upper limit of the device as it is pre-programmed
into the memory of the device by either the end-user or the
manufacturer.
Regarding measurements made relative to the pre-programmed lower
limit of the device, these are comparable to those measurements
made relative to the upper limit. As illustrated in FIG. 4, the
time T4 of first under-temperature measurement is encountered is
shown as Point E. Point F represents both the lowest temperature
encountered and the time T5 that temperature was encountered. The
time T6 that the last under-temperature occurred is shown at Point
G. The area between the temperature curve and the lower limit
represents the time integral of under-temperature excursions. Where
there is a succession of under-temperature excursions, the
cumulative integral of those excursions is stored. All of the data
A through H are stored in memory 34 of device 10, together with
data representative of the number of out-of-range excursions of
temperature (i.e. 2). These parameters are exemplary, and other
parameters and dynamic measurements may be performed by embodiments
of the present invention.
As an example, Table I shows a set of data representative of the
read-out of an exemplary device 10 set for temperature limits of
80.degree. F. and 60.degree. F., with 2 minute measurement
intervals and a 2 minute start-up delay, where the start pull-strip
was pulled at 8:50 A.M. on Sep. 16, 1991 and the stop pull-strip
was pulled at 11:16 A.M. on Oct. 1, 1991.
______________________________________ Record read: 11:16 A.M.
10/01/1991 Temperature: 76.degree. F. (75.73)
______________________________________ CONFIGURATION: Serial
number: 100 Temperature limits: 80.degree. F. 60.degree. F.
Measurement interval: 2 min Startup delay: 2 min Offset: 0 Counter
threshold: 2.degree. F. MEASURED DATA: Record start: 08:50 A.M.
09/16/1991 end: 11:16 A.M. 10/01/1991 Temperature extremes:
84.degree. F. 08:56 A.M. 09/19/1991 54.degree. F. 07:26 A.M.
09/29/1991 OVER TEMPERATURE: Time: 76 min Area: 138.degree. F.
.times. min First time: 10:50 A.M. 09/18/1991 Last time: 06:42 P.M.
09/27/1991 Number of events: 2 UNDER TEMPERATURE: Time: 2346 min
Area: 8190.degree. F. .times. min First time: 03:20 A.M. 09/28/1991
Last time: 08:42 A.M. 09/30/1991 Number of events: 3
______________________________________
.Iadd.Table I also indicates a cumulative time over-temperature of
76 minutes and a cumulative time under-temperature of 2346 minutes.
.Iaddend.
The invention may be embodied in other specific forms without
departing from the spirit or essential characteristics thereof. The
present embodiments are therefore to be considered in all respects
as illustrative and not restrictive, the scope of the invention
being indicated by the appended claims rather than by the foregoing
description, and all changes which come within the meaning and
range of equivalency of the claims are therefore intended to be
embraced therein.
* * * * *