U.S. patent application number 11/442107 was filed with the patent office on 2006-10-05 for food temperature monitoring device.
Invention is credited to Mathieu Lion, Janick Simeray.
Application Number | 20060220887 11/442107 |
Document ID | / |
Family ID | 33564532 |
Filed Date | 2006-10-05 |
United States Patent
Application |
20060220887 |
Kind Code |
A1 |
Lion; Mathieu ; et
al. |
October 5, 2006 |
Food temperature monitoring device
Abstract
Temperature monitoring device of a matter that is at least
partly made of water, such as food, comprising a wireless
temperature sensor comprising: a temperature transducer of the said
matter; an electromagnetic wave transmitter circuit connected
electrically with the temperature transducer, comprising a
converter of electric signals transmitted from the transducer in
the form of electromagnetic signals; a hermetic and good thermal
conductive case designed to be fitted out with the electric system
comprising the temperature transducer and the transmitter circuit;
wherein the sensor is laid out so that the temperature transducer
is located near to the transmitter circuit, thereby forming a
compact unit. The invention further relates to a temperature
monitoring process using the said temperature monitoring
device.
Inventors: |
Lion; Mathieu; (Paris,
FR) ; Simeray; Janick; (Argenteuil, FR) |
Correspondence
Address: |
BLAKELY SOKOLOFF TAYLOR & ZAFMAN
12400 WILSHIRE BOULEVARD
SEVENTH FLOOR
LOS ANGELES
CA
90025-1030
US
|
Family ID: |
33564532 |
Appl. No.: |
11/442107 |
Filed: |
May 25, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10615313 |
Jul 7, 2003 |
7075442 |
|
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11442107 |
May 25, 2006 |
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Current U.S.
Class: |
340/584 ;
374/E1.004 |
Current CPC
Class: |
G01K 2207/06 20130101;
G01K 1/024 20130101 |
Class at
Publication: |
340/584 |
International
Class: |
G08B 17/00 20060101
G08B017/00 |
Claims
1. Wireless temperature sensor for sensing the temperature of a
matter that is at least partly of water, including food,
comprising: a temperature transducer of said matter; an
electromagnetic wave transmitter circuit electrically connected to
the temperature transducer, comprising a converter of electric
signals coming from the transducer to electromagnetic type signals;
a hermetic and thermal conductive case designed to be fitted with
the electric system comprising the temperature transducer and the
transmitter circuit.
2. Sensor according to claim 1, wherein the electric cell is near
to the transducer and the transmitter circuit, thereby forming a
compact unit.
3. Sensor according to claim 2, wherein the electric cell is
distant from the transmitter and the transducer so that it remains
outside the matter when the sensor is inserted into the matter.
4. Sensor according to claim 3, wherein the electric cell is
protected against heat by a thermal insulating cover, thus forming
a thermal shield.
5. Sensor according to claim 4, wherein the cover is of
silicone.
6. Temperature monitoring device of a matter that is at least
partly of water, including food, intended to be placed in an oven
comprising: a wireless temperature sensor comprising: a temperature
transducer of said matter; an electromagnetic wave transmitter
circuit electrically connected to the temperature transducer,
comprising a converter of electric signals coming from the
transducer to electromagnetic type signals; a hermetic and thermal
conductive case designed to be fitted with all of the electric
system comprising the temperature transducer and the transmitter
circuit; wherein the sensor is laid out so that the temperature
transducer is located near the transmitter circuit, thereby forming
a compact unit to be completely inserted into said matter so that
it can be only subjected to the heat present inside the matter; and
a control unit autonomous and independent from the oven behaviour,
and controlling the thermal data transmitted from the sensor by
electromagnetic waves, said control unit comprising: a receiver for
the type of electromagnetic waves transmitted by the sensor; a
micro-controller capable of controlling the thermal data in
electromagnetic form received from the sensor by the receiver, and
of transmitting at least a part of it to a user interface; the user
interface comprising transmission means of the thermal data in a
form understandable to the user of the device.
7. Device according to claim 6, wherein the control unit further
comprises a memory capable of storing thermal data and wherein the
micro-controller is capable of processing the thermal data received
from the sensor in accordance with this thermal data.
8. Device according to claim 7, wherein the user interface
comprises an alarm, wherein thermal data stored in the memory
corresponds to a temperature threshold, and in that the
micro-controller triggers the alarm if the temperature detected by
the sensor is greater than the temperature threshold.
9. Temperature monitoring process according to claim 8, wherein the
part of the sensor comprising the power supply is also inserted
into said matter.
Description
[0001] This invention relates to a temperature monitoring device on
the inside of matter that is at least partly of water, such as
food, the device comprising a temperature sensor.
[0002] The invention further relates to an operating process for
this device.
[0003] The invention relates, in particular, to the temperature
monitoring of food, as much during cooking as when in a cold
chain.
[0004] Several of such devices are known of, these devices
comprising: [0005] a sensor in contact with the food, capturing
thermal data, and [0006] control means for controlling this thermal
data, delivering at least some of the thermal data in a form likely
to be understood by the user of the device.
[0007] The control means can be laid out so that the user is
alerted of an excess in temperature by means of, for example, a
light and/or sound warning set off when the sensor detects a
temperature in excess of the pre-set temperature threshold, and/or
the display of the detected temperature on a display support, such
as a LCD screen.
[0008] The sensor in these devices comprises in particular: [0009]
a food temperature transducer; [0010] connection means to connect
with the control means; [0011] an interface circuit between the
transducer and the connection means; [0012] an external case that
protects the elements that it contains.
[0013] For some of these sensors, the said connection means is
wired, such as, for example, those described in the documents U.S.
Pat. No. 3,931,620, U.S. Pat. No. 4,309,585 and US 2003 7544.
[0014] These wired connections are ergonomically restrictive for
the user of such a device, and could notably bear encumbrance and
safety problems.
[0015] Wireless temperature monitoring devices are thus
preferable.
[0016] According to a first device configuration, the said sensor
of the said control means are two distinct elements of the food
temperature monitoring device, these two elements being connected
together via a wireless electromagnetic connection, such as the
sensors described in the documents U.S. Pat. No. 4,377,733 and U.S.
Pat. No. 4,475,024.
[0017] These sensors are energised by external electromagnetic
energy sources.
[0018] Furthermore these electromagnetic sources must be located
near to the sensor so as to avoid too great a dissipation of the
electromagnetic energy during its transmission.
[0019] And the volume taken up by these electromagnetic sources
reduces the available space around the food, which could pose
encumbrance problems if this space is restricted as in, for
example, the case of the inside of ovens or freezers, whilst making
the device all the more complex through the addition of another
element.
[0020] Hence the documents JP 57-082628 and U.S. Pat. No. 3,582,921
propose wireless sensors using electromagnetic transmission,
operating either autonomously or semi-autonomously.
[0021] According to the first of these documents, a rechargeable
battery is placed in the sensor.
[0022] According to the second document, a Nickel-Cadmium electric
cell is provided in the sensor.
[0023] According to a second configuration of a food temperature
monitoring device, the sensor and the control means are
interdependent and thus form a unique element, such as described,
for example, in the document WO 90/11497.
[0024] This temperature monitoring device is autonomous as it
operates via an electric cell.
[0025] Once the thermal data has been sent by the sensor, the
control means sets off a light indicator which informs the user of
an excess in temperature at the centre of the food.
[0026] However, this display medium offers restrictions relative to
visualisation, notably when the food is placed in an enclosed area
without windows or even an opaque window, such as in some ovens or
cold rooms, as visualisation then requires an opening of the
enclosed area which could provoke technical problems
(contamination, sudden changes in temperature, etc.).
[0027] Generally speaking, each of the sensors presented in the
aforementioned documents has a long tapered part comprising at its
end a temperature transducer, and a case part distant from the
transducer for the protection of the electric circuit and of any
eventual battery found therein.
[0028] The long tapered part enables the penetration of the
transducer which it comprises into the food in order to capture the
temperature, preferably at the centre, whilst preventing the
electrical parts contained in the case from coming into contact
with the food, as the latter could contaminate it, as well as
bringing heat or cold likely to disturb its proper functioning.
[0029] However, the said temperature monitoring devices are
designed to operate in microwave ovens (in which the heat is mainly
around the piece of food), in moderately hot environments, at room
temperature or in moderately cold environments.
[0030] Indeed, the electrical parts needed to operate the
transducers of these devices are not designed to resist high
temperatures such as those attainable in convection or radiant
ovens (200.degree. C. to 300.degree. C.), nor, for some, at very
low temperatures such as those attainable in freezers (between
-30.degree. C. and -40.degree. C.).
[0031] This invention aims at improving the situation by proposing,
according to an initial aspect, a temperature monitoring device for
matter that is made at least partly of water, such as food,
comprising a wireless temperature sensor comprising: [0032] a
temperature transducer of the said matter; [0033] an
electromagnetic wave transmitter circuit electrically connected to
the temperature transducer, comprising a converter of electric
signals coming from the transducer to electromagnetic-type signals;
[0034] a hermetic and highly thermal conductive case, designed to
be fitted with the entire electrical system comprising the
temperature transducer and the transmitter circuit;
[0035] wherein that the sensor is laid out so that the temperature
transducer is near to the transmitter circuit, thereby forming a
compact unit.
[0036] Other preferential characteristics of the temperature
monitoring device according to the invention are: [0037] the sensor
further comprises an electrical power supply for the entire sensor
operating autonomously, such as an electric cell or rechargeable
battery, installed in the case; [0038] the power supply is near to
the transducer and the transmitter circuit, thereby forming a
compact unit; [0039] the power supply is distant from the
transmitter and the transducer so that it does not come into
contact with the food when the sensor is inserted into the latter;
[0040] the power supply is protected from heat by a cover of
thermal insulating material, thereby creating a thermal shield;
[0041] the cover is made of silicone; [0042] the autonomous power
supply of the sensor can operate up to a temperature of
approximately 130.degree. C. (266.degree. F.); [0043] the
autonomous power supply of the sensor can operate from a
temperature of approximately -40.degree. C. (-40.degree. F.);
[0044] the autonomous power supply of the sensor is a non saline
and non alkaline electric cell; [0045] the autonomous power supply
of the sensor is a thionyl lithium electric cell;
[0046] the case is electrically conductive and the sensor further
comprises an electric power switch-off means if the sensor in not
in contact with the said matter, the power switch-off means being
sensitive to the conductivity of the said matter; [0047] the
transmitter circuit transmits electromagnetic waves by bursts;
[0048] the hermetic case is made of a single piece; [0049] the case
is composed of several fitted parts that can be disassembled;
[0050] assembly means of two parts of the hermetic case are
metallic and create an electric contact to operate the sensor;
[0051] the case is laid out so as to facilitate the inserting of
the sensor into the said matter;
[0052] the sensor further comprises an electromagnetic wave
transmitting aerial laid out so as to further compose a means of
gripping; [0053] the aerial is covered with an electrical
insulating material;
[0054] the aerial is covered with silicone foam; [0055] the device
further comprises a control unit to control the thermal data
transmitted by the sensor via electromagnetic way, this control
unit comprising: [0056] a receiver for the type of electromagnetic
waves transmitted by the sensor; [0057] a micro-controller capable
of controlling the thermal data in electromagnetic form received
from the sensor by the receiver, and of transmitting at least a
part of it to a user interface; [0058] the user interface
comprising transmission means of the thermal data in a form
understandable to the user of the device. [0059] The control unit
further comprises a memory capable of storing thermal data, and the
micro-controller is capable of processing the thermal data received
from the sensor in accordance with this thermal data; [0060] the
user interface comprises an alarm, the thermal data stored in the
memory corresponds to a temperature threshold, and the
micro-controller triggers the alarm if the temperature detected by
the sensor is greater than the temperature threshold; [0061] the
user interface comprises means that allow the user to enter data
into the memory; [0062] the interface means comprises an alarm, and
the micro-controller triggers the alarm if it does not receive any
electromagnetic waves over a pre-set duration of time or if it does
not receive one or several thermal data informations it should have
received.
[0063] According to a second aspect, the invention proposes a
temperature monitoring process for a matter that is at least partly
of water, such as food, the matter having a temperature less than
approximately 130.degree. C. (226.degree. F.), activating the
temperature monitoring device according to one of the previous
claims, wherein the wireless part of the temperature sensor
comprising the transducer and the transmitter circuit is inserted
into the said matter.
[0064] A specific characteristic of this process is that the part
of the sensor that comprises the power supply is also inserted into
the said matter.
[0065] Other aspects, aims and advantages of this invention will be
made clearer through the reading of the following detailed
description of the device and process according to the invention,
given as non-restrictive examples and made in reference to the
annexed drawings in which:
[0066] FIG. 1 represents a cross-section view of an initial
temperature sensor according to the invention.
[0067] FIG. 2 represents an initial cross-section view of a second
temperature sensor according to the invention.
[0068] FIG. 3 represents a second cross-section view of the second
sensor represented in FIG. 2 according to line 1-1'.
[0069] FIG. 4 is a diagram representation of a temperature
monitoring device according to the invention applied to the example
of cooking food.
[0070] The temperature device according to the invention comprises
a temperature sensor designed to be inserted into a matter that is
at least partly of water, such as food, so as to read its
temperature.
[0071] In reference to FIG. 1, an example of a wireless temperature
sensor 10 is represented according to the invention comprising:
[0072] a temperature transducer 8, designed to read the temperature
within matter that is at least partly of water; [0073] an electric
circuit 7 transmitting electromagnetic waves, electrically
connected to the temperature transducer 8, comprising a converter
of electric signals coming from the transducer 8 in the form of
electromagnetic-type signals; [0074] an electric power supply 6,
electrically energising all of the electric elements of the sensor
10, and operating autonomously or practically autonomously;
[0075] a hermetic case designed to be fitted with the entire
electrical system comprising a temperature transducer 8, the
electric circuit 9 and the autonomous power supply 6.
[0076] This sensor is designed to resist extreme temperatures that
food may be exposed to, whether that be during conservation in cold
conditions or whilst being heated in an oven.
[0077] This sensor is in particular designed to resist temperatures
ranging between approximately -40.degree. C. and 130.degree. C.
[0078] There exists different types of integrable temperature
transducers 8 on the market, whose accuracy and operating
temperature ranges comply with this invention.
[0079] An oscillating type temperature transducer 8 is preferable,
mainly because this type of transducer offers little encumbrance
and is sufficiently accurate.
[0080] For example, the "Dallas Semi-conducteur" company's range of
temperature transducers includes several of such transducers,
notably those with the references DS1620, DS1721, DS1820. Their
range of calculated temperatures encompasses between -55.degree. C.
and 125.degree. C., with tolerances of about .+-.0.5.degree. C.
They operate at a voltage lying between 2V and 6V. They comprise a
non-volatile memory from which operating can be optimised. They
send a digital electric signal.
[0081] The electric circuit 7 is advantageously an hertzian wave
transmitter.
[0082] Different very simple transmitters with amplitude.
modulation, for example remote control models within the 433 MHz
range, operate in a moderate temperature range, lying between
approximately -25.degree. C. and 80.degree. C., a range which can
be extended from -55.degree. C. to more than 100.degree. C. by
adjusting the frequency settings.
[0083] For example, a "RF solution" or "Aurel" transmitter circuit
can be used if the amplitude of the carrier is modified.
[0084] Within the context of the invention, the electric circuit 7
can however be a transmitter of other types of electromagnetic
waves.
[0085] Optionally, the sensor 10 further comprises a
transmitting/receiving aerial 9 of electromagnetic waves extending
out of the sensor 10 in line with its axis and being connected
directly to the converter of the electric circuit 7 so as to
improve the quality of the electromagnetic exchanges with an
external receiver.
[0086] Optionally, this aerial 9 is long enough and made of
sufficiently rigid and solid material to also ensure the gripping
function of the sensor 10, notably to assist its insertion into the
matter to be thermal monitored.
[0087] Preferably the aerial 9 is covered with a high-temperature
protection (such as the maximum temperatures convection or radiant
ovens can attain, for example 300.degree. C. or even 350.degree.
C.) so as to avoid the user of the sensor 10 being burnt when
taking hold of the sensor via the aerial 9 to remove it from the
hot matter.
[0088] This protection may consist of covering of the aerial with
thermal insulating material of low thermal inertia.
[0089] This material can be, for example, a silicone foam that
meets the requirements, this material offering at the same time a
resistance to heat, a high thermal insulation rating and a low
thermal inertia.
[0090] Optionally the aerial 9 is covered with an electrical
insulator 11.
[0091] According to a particular configuration, this covering can
be both an electrical insulator and a protection against the said
burns, such as the said silicone cover.
[0092] The power supply 6 is advantageously an electric cell or a
battery that may or may not be rechargeable.
[0093] The autonomous electric power supply 6 operates at a wide
range of temperatures.
[0094] A non-saline and non-alkaline power supply 9 will thus be
preferable.
[0095] For example, an electric cell of thionyl lithium technology
operates within the said temperature ranges. The latter can even
bear temperatures up to 180.degree. C. without suffering any damage
if they have not been charged up.
[0096] However, an electric cell of manganese lithium technology
operates at a guaranteed working temperature from -30.degree. C. to
75.degree. C., and must therefore, if used in the sensor 10
according to the invention, be restricted to this temperature
range.
[0097] The type of power supply 6 can be adapted to the desired
usage of the sensor 10.
[0098] For example, the electric cell 6 can be changed if the
temperature range changes, even though it is preferable within the
context of the invention to use a single electric cell 6 that
operates for all the required temperature ranges.
[0099] According to another configuration of the sensor 10, the
power supply 6 is not located inside the sensor 10, but on the
outside, by means of, for example, an electromagnetic type of
energy source placed near to the sensor 10.
[0100] The hermetic case of the sensor 10 is designed to be fitted
with the entire electrical system of the sensor 10.
[0101] As this case determines the volume of the sensor 10
(excluding the optional aerial 9), it is designed to house the
electric elements (such as the transducer 8, the electric circuit 7
and the power supply 6) in a minimal space, thereby rendering the
sensor 10 as compact as possible.
[0102] In particular, the temperature transducer 8 is located near
to the electric circuit 7, contrary to the layout of temperature
sensors according to extant technologies, as previously detailed in
this document.
[0103] The internal elements of the sensor 10 represented in FIG.
1, are laid out in the case so that the power supply 6 is located
near to the case head 3, in line with the circuit 7 closely
connected with the transducer 8, the aerial 9 thus extending, at
the end of sensor 10, lengthways out of the case.
[0104] This case also advantageously has an elongated form,
resembling that of a capsule, with a case head 3 in a converging
form so as to facilitate its insertion into the matter to be
tested.
[0105] Optionally, the case head 3 is equipped with sharp elements,
such as sharp dihedral or one or several blades so as to perforate
the matter to be tested.
[0106] These sharp elements can be integral with the case head 3
forming, for example, a welded insert.
[0107] These sharp elements could be comprised in a metallic cap
fitted to the head 3. In this case, the means used to fix the cap
to the head 3 must be extremely solid so as to prevent the cap from
being left behind in the monitored matter when the sensor 10 is
retracted; these means of fixation can, for example, be screw
threads machined in the cap and on the head 3.
[0108] The case is hermetic so that chemical species coming from
the inside of the case can not escape, and that no solids, fluids
or chemicals get into the sensor 10.
[0109] The case is made of thermal conductive material so as to
precisely transmit to its interior environment the quantity of heat
from the external environment (that of the matter to be
monitored).
[0110] The case is advantageously made of electrical conductive
material, for example a metallic material, such as aluminium.
[0111] The case can be made of a single-piece or several pieces
assembled together.
[0112] The single-piece case has the advantage of being very
hermetic.
[0113] The case made of several pieces allows it to be opened so as
to replace a faulty element on the inside of the sensor 10, such
as, for example, a power supply 6 that has been used up.
[0114] In reference to FIG. 1, the case is represented in two parts
comprising a first body 1 and a second body 2 integral with the
head 3, the two bodies 1 and 2 being linked in a detachable manner
via a screw thread 4 or another means of seal-proof fixation.
[0115] In this example, the first body 1 contains the electric
circuit 7 and the transducer 8 and the second body 2 contains the
power supply 6.
[0116] According to an example of embodiment of an electric
assembly of the sensor 10 not exclusive to the invention, the case
is metallic and the earth of the power supply 6 is linked to the
second metallic body 2 via a compression spring 5. The screw thread
4, as well as serving as a means of fixation of the two bodies 1
and 2, serves as an electric joint between the second metallic body
2 and the first metallic body 1.
[0117] The transmitter circuit 7 and the thermal transducer 8 are
linked on one hand to the body 1 which serves as an earth, and on
the other hand to the power supply 6 via a direct contact with a
terminal 12.
[0118] Thus, this electric assembly allows the electric power
supply of the components of the sensor 10 to be safely switched
off, by simply detaching the sensor 10.
[0119] The thermal transducer 8 is capable of sending a modulating
digital signal to the transmitter circuit 7 which is itself linked
to the insulated aerial 9.
[0120] Thus, according to the invention, the entire system
comprised of the casees 1, 2 and 3 and the matter (comprising
water) to be monitored, of poor conductivity, constitutes an
exposed conductive part acting as the earth for the transmitting
aerial 9 protected by its insulator 11.
[0121] According to an alternative to the invention, an ergonomic
means is implemented to restrict the transmission and reading of
the temperature solely to the useful period, this corresponding to
the insertion of the sensor 10 into the matter to be monitored.
[0122] This alternative to the invention is designed to preserve
the power supply 6 and ensure a full lifespan.
[0123] This ergonomic means can be a conductive ring 14 insulated
from the body 1 via an insulation sleeve 13.
[0124] In this alternative, the positive terminal of the power
supply 6 is linked to the supply of a p-channel MOS transistor, and
the conductive ring 14 is linked to the grid of this transistor,
whereas the transmitter circuit 7 and the transducer 8 are linked
to the drain.
[0125] With a high resistance value, for example 3 megohms, of the
insulating sleeve 13, between the conductive ring 14 and the
terminal of the power supply 6, the switching-off the supply
circuit when the sensor 10 is outside the matter to be monitored is
ensured.
[0126] The matter to be monitored being at least partly of water,
it is of low conductivity and hence electrically stable.
[0127] Hence the slightly conductive matter to be monitored draws
the transistor grid to the earth, thus setting off the conduction
of the latter.
[0128] This therefore temporarily ensures the energising of the
transmitter circuit 7 and of the transducer 8 whilst the sensor 10
is being inserted into the matter to be monitored, thus allowing
energy to be consumed from the autonomous supply 6 solely when the
sensor is inside the matter to be monitored.
[0129] Still with the purpose of reducing the consumption of the
supply 6, a transmission by bursts of the electromagnetic waves
containing thermal data will be preferable, so as to preserve the
supply 6 between the bursts and thus increase its lifespan.
[0130] The sensor 10 according to the invention does not resist,
just as the thermal sensors according to extant technologies, to
high temperatures such as, for example 250.degree. C. or
300.degree. C., which are attained, for example, in radiant or
convection ovens.
[0131] However, contrary to state of the art, the geometry of this
sensor 10 (in reference to FIG. 1) is optimised to be completely
inserted into the matter to be monitored, which is sufficiently
large to contain it.
[0132] It is therefore not the heat of the oven that the sensor 10
is subjected to but the heat present inside the matter to be
monitored.
[0133] Furthermore, as long as the matter contains sufficient water
its temperature can not exceed 130.degree. C.
[0134] By way of example, the majority of meat is cooked at 47 to
80.degree. C., at its centre.
[0135] A genuine gratin Dauphinois (without the sacrilege of adding
cheese), saturated in grease, represents one of the convenience
foods the most likely to attain high temperatures (as it contains
very little water, the grease can attain high temperatures and the
cooking time of the potatoes is long) such as, for example,
temperatures ranging between 120.degree. C. and 130.degree. C.
[0136] Thus according to the invention, all of the electronic
elements of the autonomous sensor 10, kept at the centre of the
food, and not on the surface, are not subject to external high
temperatures, as these elements do not exceed the final cooking
temperature of the food, thus ensuring normal usage of the sensor
10.
[0137] Hence such a sensor 10 allows the temperature of food to be
monitored that is being subjected to extreme heat, something which
was not possible with prior technologies.
[0138] Of course, if the food is too hot, the water will eventually
completely evaporate, and too high a temperature will destroy the
sensor 10 (however, in such an event, the gratin Dauphinois is also
burnt black!). Means of temperature alarms so as to overcome such
problems will be described later.
[0139] Moreover, due to the compactness and conductivity of the
case of the sensor 10, all of its internal elements are at the same
temperature, that of the monitored matter.
[0140] The sensor 10 being wireless it is not subject to safety or
encumbrance difficulties as could be the case in the presence of
electric wires in an oven.
[0141] Finally the sensor 10 is compact, thus reducing its
encumbrance, notably when it is completely inserted into the food,
with only the aerial 9 jutting out.
[0142] The description of the application of the sensor 10 to the
monitoring of a cold chain is generally speaking similar to that of
the sensor 10 to the monitoring of heat, except for the following
points: [0143] the operating temperature of the sensor is extended
to approximately -40.degree. C.; [0144] the sensor 10 is not
inserted into the food but is adjacent to it, the temperatures of
the food, of the sensor 10 and of the casing being substantially
equivalent; [0145] the temperature of the refrigerated casing does
not compromise to working order of the sensor, which resists in the
long term; [0146] the commutation system described above, which
allows the sensor 10 to be supplied with electricity when it is
inside the food, can therefore not operate in cold conditions;
thus, the sensor continually transmits, via bursts, and the
fastening of the case of the sensor 10 always renders the
transmitter circuit 7 and the temperature transducer 8 live; [0147]
the silicone foam protects the user from skin bonding against the
metallic aerial 9, thus allowing the sensor to be handled without
any risks.
[0148] The sensor 10 also operates at intermediate temperatures,
both hot and cold, such as room temperature.
[0149] In reference to FIGS. 2 and 3, a second temperature sensor
10 according to the invention is represented.
[0150] This second sensor 10 is substantially comprised of the same
elements as those described by the first sensor 10 (represented in
FIG. 1).
[0151] The configuration of this second sensor 10 is however
different, as the power supply 6 is now located to the end 1 of the
sensor 10, and the unit consisting of the transducer 8 and the
transmitter circuit 7 (not represented in FIGS. 2 and 3) is within
the head 2 of the sensor 10.
[0152] The power supply 6 is therefore fitted between the
transducer-transmitter circuit unit and the aerial 9.
[0153] Such a configuration of the sensor 10 is particularly well
adapted when its usage consists of only inserting, the power supply
6 and the aerial 9 coming out of the food into the food, the head 2
of the sensor 10, and the usage planned for the first sensor 10
(referenced to in FIG. 1) when the power supply 6 was also inserted
into the food.
[0154] This usage, if applied to high temperatures such as those
present in convection and radiant ovens, requires a thermal
protection of the power supply 6.
[0155] The type of protection chosen for the sensor 10 is that of a
thermal shield 11 surrounding the end piece 1 of the sensor 10
(comprising the power supply 6) with thermal insulating
material.
[0156] For example, this material is of silicone.
[0157] Advantageously, this thermal shield 11 further covers the
aerial 9 so that both the power supply 6 and the aerial 9 are
protected from heat via the same protection medium.
[0158] The thickness of the thermal shield 11 is then adjusted so
that the temperature at the power supply 6 lies within its
tolerance range.
[0159] As before, a thionyl lithium electric cell can be chosen as
the power supply 6.
[0160] In reference to FIG. 3, a cross-section view shows a design
of the head 2 of the sensor 10 so that the latter can be easily
inserted into the food.
[0161] Here, the chosen design is quite narrow with sharp edges and
point, comparable to the blade of a pointed knife.
[0162] In reference to FIG. 4, the example of an application of the
illustrated invention is the monitoring of the cooking of food 40
(in this case a free-range chicken) in an oven 30, through the use
of a temperature monitoring device on the inside of the food 40
according to the invention.
[0163] The monitoring device according to the invention that is
represented comprises: [0164] a wireless temperature sensor 10
capable of reading thermal data; and [0165] a control unit 20
capable of handling this thermal data.
[0166] The temperature sensor 10, in compliance with the invention,
is inserted into the food 40, using, for example, the aerial 9 as a
means of gripping (see the above in this document).
[0167] If the sensor 10 corresponds to the first sensor 10 (in
reference to FIG. 1), the entire sensor 10 excluding the aerial 9
can be inserted into the food.
[0168] If the sensor 10 corresponds to the second sensor 10 (in
reference to FIGS. 2 and 3) the entire sensor 10 excluding the
aerial 9 and the power supply 6, is inserted into the food.
[0169] As indicated above, according to a particular electric
configuration of the sensor 10, the food 40, of low electric
conductivity, touches the sensor 10 and switches on the autonomous
electric operating of the sensor 10.
[0170] Bursts of electromagnetic signals are thus transmitted from
the sensor 10, these signals comprising the thermal data captured
in the food 40 by the transducer 8.
[0171] The control unit 20 then receives these electromagnetic
signals so as to deliver at least some of the thermal data that
they contain in a form likely to be understood by the user of the
device.
[0172] For this purpose, the control unit 20 comprises a means of
electromagnetic wave reception (such as an aerial), an electric
circuit with amplitude or frequency modulation, a micro-controller,
a user interface comprising means for transmitting thermal data in
a form understandable to the user.
[0173] The means for receiving the electromagnetic waves receives
the electromagnetic signals transmitted by the sensor 10, and
transmits them to the modulation electric circuit.
[0174] The modulation electric circuit then converts the
electromagnetic signals into electric or digital signals and
transmits them to the micro-controller.
[0175] Then, the micro-controller converts these digital signals
into interfacing signals capable of activating (or not activating)
the user interface, these signals being then transmitted to the
user interface which lastly delivers the thermal data to the user
in a form understandable to the user.
[0176] This control unit 20 can, for example, comprise one or
several of the following user interface media: a screen, such as a
LCD; one or several light emitting diodes; an acoustic
diaphragm.
[0177] The control unit 20 can further comprise an interactive user
interface medium allowing the user to communicate signals via the
control unit 20, such as a keyboard, mouse or infrared portion of
Bluetooth type.
[0178] Advantageously, this control unit 20 further comprises a
memory that allows thermal data and possibly algorithms to be put
to memory, which can be deleted, modified or programmed by the user
via an interactive interface medium.
[0179] In this case, the micro-controller can compare the measured
thermal data with the thermal data stored in the memory to handle
the outgoing signal to the user interface.
[0180] The user can, for example, program via a programming
keyboard, the cooking temperature of the free-range chicken, the
data then being stored in the memory of the control unit 20 as a
temperature threshold temperature (at which the free-range chicken
is cooked to a perfection).
[0181] The micro-controller that receives the calculated thermal
data will compare it with this temperature threshold, and then
sends, when the calculated temperature is equal to or in excess of
the temperature threshold, a signal to an appropriate interface
which will alert the user via an alarm (sound or light).
[0182] At the same time, the micro-controller can transmit the
thermal data to a LCD screen so that the latter displays the
calculated temperatures.
[0183] Thus, according to the invention, other types of alarm can
be envisaged such as, for example: [0184] an activating of the
control unit 20 prior to the sensor 10 being inserted into the food
triggers an alarm; [0185] a disappearing of the electromagnetic
link after a pre-set time period or the absence of a pre-set number
of bursts triggers an alarm; [0186] the draining of the autonomous
power supply 6 of the sensor 10 triggers an alarm as it interrupts
the transmission; [0187] the recording of a temperature that is out
with the authorised limits for the efficient operating of the
sensor 10 triggers the recording to the memory of the monitoring
case and a message appears on the display of the latter.
[0188] The second example allows in particular the monitoring
device to be made more reliable, and in particular the sensor 10,
as an alarm is triggered when the sensor 10 operates
abnormally.
[0189] This is ensured, for example, in that any breakage in the
link for more than three bursts triggers the alarm.
[0190] In the fourth example, the user is alerted of the risk of a
consecutive incident due to a monitoring fault and a reactive
deficiency of the alarm (and the manufacturer can, thus be held
harmless to a faulty reaction of the user's alarm).
* * * * *