U.S. patent application number 12/104465 was filed with the patent office on 2009-10-22 for apparatus for the heat storage of foodstuffs.
This patent application is currently assigned to PORKKA FINLAND OY. Invention is credited to Juha KAUPPINEN, Paavo SAVELIUS.
Application Number | 20090261175 12/104465 |
Document ID | / |
Family ID | 41200296 |
Filed Date | 2009-10-22 |
United States Patent
Application |
20090261175 |
Kind Code |
A1 |
KAUPPINEN; Juha ; et
al. |
October 22, 2009 |
APPARATUS FOR THE HEAT STORAGE OF FOODSTUFFS
Abstract
The invention relates to an apparatus (1) for the heat storage
of foodstuffs, provided with an aperture for taking foodstuffs out
of the interior (T) of the apparatus and for setting them in the
interior (T) of the apparatus, adjusting devices (4) for adjusting
the relative humidity and temperature of air located in the
interior (T) of the apparatus, said adjusting devices comprising at
least one air moisturizing unit (2) provided with an essentially
horizontal water reservoir (23). The adjusting devices (4) for
adjusting the relative humidity and temperature in the interior (T)
further comprise: at least one unit (3) for lowering the relative
humidity of air, comprising a vertical housing (30), open at the
top and bottom ends, placed in the interior (T) of the apparatus,
inside which housing there are provided means for lowering (32) the
relative humidity of air and transmission means (31) for taking air
from the top part of the interior (T) of the device and for
discharging air from the bottom part of the housing (30) in the
direction of the bottom (P) of the apparatus, so that by means of
said unit (3), only a certain part (I') of the total air mass (I)
contained in the interior (T) of the apparatus can at a time be
lowered to a lower relative humidity without actively taking
replacement air from outside the apparatus, in which case each
housing (30) is placed in the interior of the apparatus (1), at a
point where the air flow proceeding downwards from the lower edge,
towards the bottom, is turned towards the inner walls (1a, 1b) of
the apparatus, said air moisturizing unit (2), which is located
lower than the lower edge of the housing (30) and where at least a
water reservoir (23) can be pulled out of the interior (T) of the
apparatus, an adjusting system (5) for measuring and adjusting the
temperature and moisture of foodstuff and the air temperature and
air humidity in the interior (T), said system comprising a
measuring unit (7) provided with at least one sensor (73) for
measuring the relative humidity of air, one sensor (72) for
measuring the air temperature and possibly sensors (71) that can be
used for measuring the temperature and/or moisture of foodstuffs; a
unit (51) for collecting, processing and recording temperature and
humidity data as well as an adjusting unit (52) for adjusting air
temperature and air humidity.
Inventors: |
KAUPPINEN; Juha;
(Hameenkoski, FI) ; SAVELIUS; Paavo; (Viekijarvi,
FI) |
Correspondence
Address: |
YOUNG & THOMPSON
209 Madison Street, Suite 500
ALEXANDRIA
VA
22314
US
|
Assignee: |
PORKKA FINLAND OY
HOLLOLA
FI
|
Family ID: |
41200296 |
Appl. No.: |
12/104465 |
Filed: |
April 17, 2008 |
Current U.S.
Class: |
236/44C ;
165/223; 236/44A |
Current CPC
Class: |
A47J 39/006
20130101 |
Class at
Publication: |
236/44.C ;
236/44.A; 165/223 |
International
Class: |
F24F 3/14 20060101
F24F003/14; F24F 3/12 20060101 F24F003/12 |
Claims
1. An apparatus (1) for heat storage of foodstuffs, provided with
an aperture for taking foodstuffs out of the interior (T) of the
apparatus and for setting them in the interior (T) of the
apparatus, adjusting devices (4) for adjusting the relative
humidity and temperature of air located in the interior (T) of the
apparatus, said adjusting devices comprising at least one air
moisturizing unit (2) provided with an essentially horizontal water
reservoir (23), characterized in that the adjusting devices (4) for
adjusting the relative humidity and temperature in the interior (T)
further comprise: at least one unit (3) for lowering the relative
humidity of air, comprising a vertical housing (30), open at the
top and bottom ends, placed in the interior (T) of the apparatus,
inside which housing there are provided means for lowering (32) the
relative humidity of air and transmission means (31) for taking air
from the top part of the interior (T) of the device and for
discharging air from the bottom part of the housing (30) in the
direction of the bottom (P) of the apparatus, so that by means of
said unit (3), only a certain part (I') of the total air mass (I)
contained in the interior (T) of the apparatus can at a time be
lowered to a lower relative humidity without actively taking
replacement air from outside the apparatus, in which case each
housing (30) is placed in the interior of the apparatus (1), at a
point where the air flow proceeding downwards from the lower edge,
towards the bottom, is turned towards the inner walls (1a, 1b) of
the apparatus, said air moisturizing unit (2), which is located
lower than the lower edge of the housing (30) and where at least a
water reservoir (23) can be pulled out of the interior (T) of the
apparatus, an adjusting system (5) for measuring and adjusting the
temperature and moisture of foodstuffs and the air temperature and
air humidity in the interior (T), said system comprising a
measuring unit (7) provided with at least one sensor (73) for
measuring the relative humidity of air, one sensor (72) for
measuring the air temperature and possibly sensors (71) that can be
used for measuring the temperature and/or moisture of foodstuffs; a
unit (51) for collecting, processing and recording temperature and
humidity data as well as an adjusting unit (52) for adjusting air
temperature and humidity.
2. An apparatus (1) according to claim 1, characterized in that it
contains one or several chambers (100), at least part of said
chambers being provided with their own specific unit (3) for
lowering the relative humidity of air and their own specific
moisturizing unit (2).
3. An apparatus (1) according to claim 2, characterized in that at
least part of the chambers are provided with measuring units (7)
containing a thermometer (72) for measuring the air temperature in
the interior (T), a moisture meter (73) for measuring the relative
humidity of the air in the interior (T) and a injection thermometer
(71) for measuring the temperature of the foodstuffs (S), all of
said devices being connected to the adjusting unit (52).
4. An apparatus (1) according to claim 1, characterized in that the
adjusting unit (52) for adjusting the temperature and humidity of
air comprises an adjusting element for dispensing the water that is
vaporized from the air moisturizing unit (2) for example by
intermediation of a mat resistor (22), and an adjusting element for
heating the air mass (I') placed in the housing (30) of the
adjusting unit for example by intermediation of a resistor
(32).
5. An apparatus (1) according to claim 1, characterized in that the
housing (30) is located approximately in the middle of the interior
(T) of the apparatus, and that inside the vertical housing (30)
that is open at its top and bottom ends, there is arranged a
resistor (32) for heating the air and a blower (31) for blowing the
air out of the bottom part of the housing towards the bottom (P) of
the apparatus.
6. An apparatus (1) according to claim 1, characterized in that the
air moisturizing unit (2) comprises an essentially horizontal water
reservoir (23), a resistor (22) for indirectly heating the water in
the water reservoir, and a carriage for moving the water reservoir
(23) along guide bars (61) to the interior (T) of the apparatus and
out of the interior (T) of the apparatus.
7. An apparatus (1) according to claim 6, characterized in that the
air moisturizing unit (2) includes a mat resistor (22), which is
placed so that it can heat the exterior of the water reservoir
(23), preferably the bottom part of the exterior.
8. An apparatus (1) according to claim 6, characterized in that the
air moisturizing unit (2) is located on the same vertical line (S)
as the vertical housing (30), or immediately adjacent to said
vertical line (S).
9. An apparatus (1) according to claim 8, characterized in that the
air moisturizing unit (2) is arranged detachably at the bottom (P)
of the apparatus or in the immediate vicinity thereof, on
horizontally (I) running guide bars (61).
10. An apparatus (1) according to claim 1, characterized in that in
the interior of the apparatus, there is arranged at least one heat
storage chamber (100), so that each chamber is defined by the inner
walls, ceiling and bottom of the device, as well as a possible
partition wall (12) dividing the interior (T), said partition wall
comprising an element arranged in the widthwise (I) direction of
the apparatus, which element essentially prevents air from flowing
from one chamber to another.
11. An apparatus (1) according to claim 1, characterized in that
the apparatus also comprises a number of horizontal container
vessels (9), advantageously located in the interior (T) of the
apparatus, preferably below the middle level of the interior, on
which vessels foodstuffs (S) can be placed.
12. An apparatus (1) according to claim 1, characterized in that
the unit (3) of the adjusting device (4), meant for lowering the
relative humidity of air, is a rectangular vertical housing that is
detachably connected on vertical support beams (6) arranged in the
interior of the apparatus, so that the lengthwise direction of said
housing proceeds in the widthwise direction (1) of the apparatus,
and that the air moisturizing unit (2) is placed detachably at the
bottom (P) of the apparatus or in the vicinity thereof, on
horizontal guide bars (61) of two adjacent pairs of support beams
(8).
13. An apparatus (1) according to claim 1, characterized in that it
is integrated with a food dispensing device (700), a food gathering
plane, a heated or unheated top plane, a heat compress, a warm or
neutral plate dispenser arrangement, in which case against the
upper surface of the device (1) meant for heat storage, there may
also be supported heated or unheated storage shelves and cabinets,
as well as light fixtures and heat radiators that are located above
the food dispensing, serving, preparing and processing
equipment.
14. A method for adjusting the temperature and relative humidity of
the interior air in a heat storage apparatus (1) according to claim
1, characterized in that only a certain part (I') of the total air
mass (I) contained in the interior (T) of the apparatus is at a
time lowered to a relative humidity lower than that of the rest of
the air mass contained in the interior (T), in a housing (30)
provided in the interior, so that the air mass (I') is taken from
the top part of the interior (T) to the housing (30), its humidity
is lowered to a relative humidity lower than that of the rest of
the air mass inside the housing, and thereafter the air mass (I')
is conducted, by means of the housing (30), to the bottom part of
the interior and set in a motion directed downwards and further
towards the inner walls (1a, 1b) of the apparatus when being
discharged from the housing (30), the amount of water vaporized
from the moisturizing unit (2) and the heat amount to be
transferred to a certain part (I') of the air mass (I) contained in
the interior (T), and possibly also the transfer rate of said
heated air after heating, is adjusted on the basis of measurement
results obtained from a temperature sensor (72) measuring the
temperature of the interior (T) and from a sensor (73) measuring
the relative humidity of the interior air, by means of an adjusting
unit (52), so that an even and desired relative humidity (RH %) and
temperature prevail in the whole interior (T).
15. A method according to claim 14, characterized in that the
adjusting unit (52) dispenses moisture in the air by a water
heating resistor (22) of the moisturizing unit (2) and heats the
air mass (I') contained in the housing (30) by intermediation of a
resistor (32).
16. A method according to claim 15, characterized in that the
amount of water vaporized from the moisturizing unit (2) and the
heat amount to be transferred to a certain part (I') of the air
mass (I) contained in the interior (T), inside the housing (30),
and possibly also the transfer rate of said heated air out of the
housing (30) by means of a blower arranged in said housing, are
adjusted by a PDI adjusting unit and/or a digital thermostat
provided in the adjusting unit (52).
17. A method according to claim 15, characterized in that the
temperature of the foodstuff contained in the container vessels (9)
is measured from time to time by a temperature sensor (71), and on
the basis of the measurement results obtained from the sensor (71),
the amount of the water vaporized from the moisturizing unit (2) is
adjusted, as well as the heat amount to be transferred to a certain
part (I') of the air mass (I) contained in the interior (T), and
possibly also the transfer rate of said heated air after
heating.
18. A method according to claim 14, characterized in that the
relative humidity of the air mass (I) contained in the interior (T)
is maintained more or less the same as the balance moisture of the
foodstuffs (S) stored in the interior (T).
19. A method according to claim 14, characterized in that the
readings of the relative humidity (RH %) of the air in the interior
(T) and the temperature (T) are measured, and that the relative
humidity of air is measured at certain intervals or continuously,
and the measured readings are stored and/or sent to a control
unit.
20. A method according to claim 19, characterized in that air is
sucked in to be heated in the housing (30) through the top part of
the interior (T) and conducted through or past the heating resistor
(32) of the housing, towards the bottom (P) of the heat storage
apparatus (1), from where the air flow is arranged to turn in the
direction of the bottom towards the inner walls (1a, 1b) of the
apparatus.
21. A method according to claim 20, characterized in that at least
part of the heated air mass (I') is after heating arranged to be
directed to a heatable water reservoir (23) of the air moisturizing
unit (2), which reservoir is advantageously located in the vicinity
of the bottom (P) of the apparatus (1), so that air circulates
through the shortest possible route from the unit (3) meant for
lowering the relative humidity of air, to the air moisturizing unit
(2) and further to the foodstuffs contained in said container
vessels (9).
22. A method according to claim 20, characterized in that the air
mass moisturized by the moisturizing unit (3) is arranged to
proceed from the foodstuffs contained in the container vessels (9)
towards the inner walls (1a, 1b) of the apparatus and to turn at
the inner walls upwardly towards the ceiling of the apparatus, from
where the air circulates to the top part of the unit (2) meant for
lowering the relative humidity of air.
Description
[0001] The invention relates to an apparatus according to the
preamble of claim 1 that can be used for the storage of
foodstuffs.
[0002] The invention also relates to a method according to the
preamble of claim 14 for adjusting the air temperature and relative
humidity in the interior of a heat storage apparatus.
[0003] When foodstuffs are kept warm for distribution by a
conventional, air-heated heat storage apparatus, the foodstuffs are
remarkably dried up as the moisture is vaporized therefrom. This
results in changes in the surface structure of the foodstuffs, and
the food looses its succulence and becomes wilted.
[0004] In so-called low temperature stoves, this problem is solved
so that the foodstuff's own moisture is utilized for creating a
vapor block during the heating process. Even if the product
(=foodstuff) is thus prevented from further drying during the
heating, the product still dries when moisture is evaporated for
forming the vapor block. The principle of forming a vapor block,
known from low temperature stoves, does not function in devices
designed for food distribution and for keeping food warm, such as
heat cabinets, because the heat cabinet doors must be continuously
opened and closed, so that the vapor block created in the interior
of the cabinet evaporates.
[0005] In the prior art, attempts have been made to eliminate the
above mentioned problem by means of heat storage apparatuses
provided with a separate heating and moisturizing unit, by which
the interior air temperature and relative level of humidity in the
heat storage apparatus is attempted to be maintained suitable for
each foodstuff. The employed moisturizing unit is a water
reservoir, on the bottom of which there is arranged a fairly large
electric resistor, by which aqueous steam is vaporized in the air
space. A suitable relative level of humidity for each foodstuff at
a certain temperature is the same as the quantity of active water
contained in said foodstuff at the temperature in question.
Suitable relative humidities of foodstuffs are discussed in the
literature. For the heating of a heat storage cabinet, there are
used heating elements connected to the inner walls of the cabinet,
and a possible air flow is created by means of a high-power
blower.
[0006] Even if the method used in the above described heat storage
apparatuses solves some of the problems connected to heat storage
cabinets and the wilting of foodstuffs, because moisture is brought
from outside into the storage space of the apparatus to replace the
moisture that has evaporated from the foodstuffs, it is difficult
for heat storage apparatuses applying said method, such as heat
cabinets, to maintain an even humidity and temperature in the
interior, particularly if the cabinet has a large storage capacity.
Uneven temperature and humidity conditions inside the cabinet
result in that in some parts of the cabinet, there are left pockets
where the moisture level is too high/low with respect to keeping up
the correct moisture level. The former results in the wilting of
the food, the latter in its becoming watery, which both are
undesirable phenomena with respect to the storage of food.
[0007] The main problem with this kind of heat storage cabinet,
inside of which even temperature and humidity conditions cannot be
maintained, is that the range of usage of the cabinet is
drastically reduced, because its size and hence its storage
capacity must be maintained relatively small. Consequently, this
kind of heat cabinet cannot be connected for example to such
high-capacity food dispensing devices that are used for instance in
institutional kitchens, canteens and restaurants. The above
described capacity problems in these known heat cabinets arise from
problems in the air circulation, and as a result, the moisturized
air is not distributed evenly in the air mass inside the
cabinet.
[0008] Another main problem in the prior art has been connected to
the requirements for collecting and recording the history of
foodstuffs storage temperature in the foodstuffs processing chain.
In the prior art heat storage apparatuses, food temperature does
not remain constant, due to the evaporation of moisture when
opening and closing the door. An even humidity and temperature
inside the cabinet is essentially important, among others, for the
control of the heating and moisture history of foodstuffs, and for
instance in the above described prior art method, moisture is
distributed unevenly inside the storage space, and the temperature
measuring process easily becomes unreliable, when the temperature
and humidity levels fluctuate remarkably in the internal air of the
apparatus.
[0009] A third drawback in prior art heat storage cabinets is their
susceptibility to the growth of microbial population, due to
drawbacks both in the device technology and methods. In heat
storage cabinets, food is generally meant to be kept more or less
at the serving temperature, which falls within the growth range of
several microbes. In case the heat storage cabinet also is
functionally connected to food distribution, collection or
processing equipment, the cabinet door must be continuously opened
and closed. In prior art heat cabinets, where it is not possible to
create efficient humidity and temperature conditions that would
also be homogeneous throughout the whole interior of the cabinet,
the cabinet walls are easily dried. In case food happens to stick
to the heat cabinet walls when it is taken out or put in, it easily
burns on the walls, particularly in a case where the heating of the
storage cabinet interior is carried out through the inner walls.
Such dried-up leftovers form potential substrates for microbial
growth. In some prior art heat storage cabinets, water is heated by
a resistor placed in a water reservoir that is permanently
installed on the bottom of the device, and water is fed to the
reservoir through a water conduit. This kind of water reservoir is
extremely susceptible to getting dirty.
[0010] A fourth drawback in prior art heat storage cabinets has
been the high energy consumption of the cabinets, which has mainly
been due to the high-power heating and blowing equipment used in
the cabinets, as well as to the intake of fresh replacement
air.
[0011] The object of the invention is to realize an apparatus for
the heat storage of foodstuffs, in which the drawbacks of the prior
art can be eliminated.
[0012] Hence the main object of the invention is to realize an
apparatus for the heat storage of foodstuffs, in the whole interior
of which there is created a temperature and relative humidity of
air that can be kept constant in all conditions, The relative
humidity should be approximately the same as the quantity of active
water contained in the foodstuffs at said temperature.
[0013] A second object of the invention is to realize an apparatus
for the heat storage of foodstuffs, in which apparatus the level of
hygiene can be kept sufficient in all usage conditions.
[0014] A third object of the invention is to realize a heat storage
apparatus that is energy-efficient in all conditions.
[0015] More precisely, the invention relates to an apparatus for
the heat storage of foodstuffs according to the characterizing part
of claim 1.
[0016] The invention also relates to a method for adjusting the
temperature and relative humidity of the air contained in the
interior of the heat storage apparatus according to claim 1.
[0017] An apparatus according to the invention, meant for heat
storage of foodstuffs, is provided with an aperture for taking
foodstuffs out of the interior of the device and for putting them
in the interior of the device, as well as adjusting means for
adjusting the relative humidity and temperature of the air
contained in the interior of the apparatus. The adjusting means for
adjusting the relative humidity and temperature of the air
contained in the interior of the apparatus include at least one air
moisturizing unit comprising an essentially horizontal water
reservoir. The adjusting means further comprise: [0018] at least
one unit for reducing the relative humidity of air, said unit being
designed for heating air and conducting it in a controlled manner,
comprising a vertical housing that is located in the interior of
the apparatus and is open at the top and bottom ends and includes
means for reducing the relative humidity of air as well as
transferring means for taking air from an upper part of the
interior and conducting air from the lower part of the housing
towards the bottom of the apparatus. Said unit can be used for
reducing the relative humidity in only a certain part of the total
air mass contained inside the apparatus, without actively taking
replacement air from outside the apparatus, in which case each
housing is placed in the interior of the apparatus, at a location
where the air flow proceeding downwards, towards the bottom
underneath its lower edge, turns towards the inner walls of the
apparatus; [0019] an air moisturizing unit that is located lower
than the lower edge of the housing and where at least the water
reservoir can be pulled out of the interior of the apparatus;
[0020] an adjusting system for measuring and adjusting the interior
air temperature and air humidity of foodstuffs, said system
comprising at least one sensor for measuring the relative humidity
of air, at least one sensor for measuring the air temperature and
possibly sensors that can be used for measuring the temperature
and/or moisture of foodstuffs; an unit for collecting, processing
and recording temperature and humidity data and for adjusting the
air temperature and air humidity in the apparatus.
[0021] Additionally, the invention relates to a method for
adjusting the temperature and relative humidity of the interior air
in a heat storage apparatus In this method: [0022] only a certain
part (I') of the total air mass (I) contained in the interior (T)
of the apparatus is at a time lowered to a relative humidity lower
than that of the rest of the air mass contained in the interior
(T), in a housing (30) provided in the interior, so that the air
mass (I') is taken from the top part of the interior (T) to the
housing (30), its humidity is lowered to a relative humidity lower
than that of the rest of the air mass inside the housing, and
thereafter the air mass (I') is conducted, by means of the housing
(30), to the bottom part of the interior and set in a motion
directed downwards and further towards the inner walls (1a, 1b) of
the apparatus when being discharged from the housing (30), [0023]
the amount of water vaporized from the moisturizing unit (2) and
the heat amount to be transferred to a certain part (I') of the air
mass (I) contained in the interior (T), and possibly also the
transfer rate of said heated air after heating, is adjusted on the
basis of measurement results obtained from a temperature sensor
(72) measuring the temperature of the interior (T) and from a
sensor (73) measuring the relative humidity of the interior air, by
means of an adjusting unit (52), so that an even and desired
relative humidity (RH %) and temperature prevail in the whole
interior (T).
[0024] The basic idea of the invention is to place a water
vaporizing unit in the interior of an apparatus meant for heat
storage of foodstuffs for moisturizing the air, and a separate unit
arranged in a closed space for reducing the relative humidity of
air and for transferring the air mass, generally comprising air
heating and blowing equipment. The employed air heating and
transferring unit is a device that heats and blows air with special
targeting. The term targeted heating here means that of the total
air mass contained in the interior, there is at a time heated only
a certain part left inside the housing located in the interior of
the apparatus. After leaving the housing, the air heated inside the
housing is blown from top to bottom, in which case said blown air
is set in a circulating motion directed upwards from the bottom,
said circulating motion being the natural flowing direction of the
air that is warmer than its surroundings. The water vaporizing unit
is located below the lower edge of the air heating and transferring
unit, along the same vertical line as said air heating and
transferring unit, or immediately adjacent to said vertical line.
Now the air that has left the air heating and transferring unit
proceeds to the vaporizing unit, and after passing it, transfers
the moisture evenly to the whole air mass in the interior of the
apparatus. When air is heated inside the closed housing, its
relative humidity is reduced. By blowing the heated air with a
relative humidity lower than that of the surroundings towards the
water reservoir located at the bottom of the device, a maximum
amount of aqueous steam can be bound to the air. In an apparatus
according to the invention, replacement air is not actively taken
from outside, as opposed to some corresponding prior art
arrangements, and therefore there is achieved a more accurate
adjusting of the air humidity and temperature. The water vaporizing
unit included in the apparatus according to the invention can be
moved to outside the apparatus, which brings forth a remarkable
advantage from the point of view of cleaning the equipment. In
addition, the apparatus also includes an adjusting system,
generally comprising one sensor for measuring the relative humidity
of the interior air, and one sensor for measuring the temperature
of the interior air, as well as a sensor that can be used for
taking random samples of temperature and/or humidity of the
foodstuffs contained in the storage chamber. The adjusting system
is used for collecting temperature and humidity data from the
interior, and on the basis of said data, the adjusting unit changes
the temperature and humidity of the interior air.
[0025] In this application, the interior of the apparatus refers to
the space defined by the bottom, ceiling and walls (including
doors) of the heat storage apparatus, which space can be used for
the storage of foodstuffs.
[0026] Additionally, the term storage chamber refers to that part
of each apparatus that has its own air circulation, i.e. a water
vaporizing unit and an air heating and blowing unit.
[0027] Deficiency of active replacement of air means that the
apparatus only takes air through the door, i.e. generally when
foodstuffs are put in or removed therefrom.
[0028] The above described drawbacks connected to the prior art are
eliminated by the use of this kind of apparatus meant for the heat
storage of foodstuffs: water is vaporized either continuously, when
necessary or according to preset values in the interior of the
apparatus, where it is distributed evenly to the whole air space,
owing to the recirculation of air. Now an opening of the door of
the apparatus does not dry up the foodstuffs, because the aqueous
steam that escaped when the door was opened is replaced by water
vaporized in the vaporizing unit. Neither does an opening of the
door affect the humidity of the and air flows to any great extent,
because only a small part of the air mass is at a time transferred
by blowing, and a blow is directed from top to bottom; in prior art
devices, the blowers are placed in the rear wall or the ceiling,
and they are used for transferring a large part of the air mass
contained in the space, in which case an opening of the door
results in that the blowers blow part of the air directly out of
the door, thus enhancing the process of lowering the relative
humidity.
[0029] The drawback typical to prior art devices, i.e. the problem
to achieve a sufficient level of hygiene, is in an apparatus
according to the invention solved first of all by heating the water
reservoir indirectly, i.e. the water reservoir is not heated by
means of a resistor placed in an open space in the water reservoir,
but indirectly by a resistor placed underneath the bottom of the
water reservoir, which resistor is advantageously a mat resistor.
Another factor that ensures the level of hygiene in an apparatus
according to the invention is the above described generation of
even moisture in the interior of the apparatus, in which case any
food that happens to get on the walls cannot burn and stick to the
inner walls of the apparatus. By distributing the aqueous steam
evenly in the interior of he apparatus, there is achieved the
advantage that when the apparatus is made as a heat storage
cabinet, the capacity of the interior of the apparatus can be made
larger than usual. A high-capacity heat storage apparatus can be
connected to food distribution equipment. The air heating and
transferring units provided in the heat storage apparatus, the
moisture adjusting unit and the vessels used for storing the
foodstuffs are advantageously detachable, which helps to keep up a
sufficient level of hygiene in the interior of the apparatus. The
water vaporizing unit belonging to the apparatus according to the
invention can be moved to outside the apparatus, in which case it
is easily cleaned, and a separate water duct to the water reservoir
is not needed in the apparatus.
[0030] With respect to the further advantages achieved by the
invention, let us point out the following: the advantage achieved
by even humidity and temperature conditions is a drastic
improvement in the reliability of measuring temperature and
interior air humidity; at present, there is needed precise
information as regards the moisture and/or temperature history of
foodstuffs during the processing thereof. Irrespective of the
larger size of the interior of an apparatus according to the
invention with respect to prior art apparatuses, the interior air
temperature/humidity can be measured and adjusted reliably and
automatically for example by suitable logics, provided with one
humidity and temperature sensor per storage chamber, installed in
the interior of the apparatus, a data storage means where data can
be stored for further control, and an adjusting unit by which the
interior air temperature and humidity are adjusted by vaporizing
moisture in the water vaporizing unit and by heating air by the air
heating resistor provided in the housing. Because only a small part
of the total air mass contained in the interior of the apparatus is
processed at a time (heating+blowing) in a housing arranged
separately in the interior, and replacement air is not actively
taken from outside, the apparatus can use air heating resistors and
blowing equipment with a remarkably lower power consumption than in
known heat storage apparatuses that process the total air mass
contained in the interior of the apparatus, and replacement air
with a different temperature is taken from outside.
[0031] Other advantages achieved by the invention and its various
preferred embodiments are apparent from the appended drawings and
their description, as well as from the dependent claims that refer
to preferred embodiments of the invention.
[0032] FIG. 1 shows a simplified perspective illustration of a heat
storage cabinet according to the invention, with the cabinet front
wall removed.
[0033] FIGS. 2A and 2B are schematical illustrations of an
adjusting system used in an apparatus according to FIG. 1, provided
with an interior air humidity and temperature adjusting and
measuring arrangement, and humidity and temperature data processing
units.
[0034] FIG. 3A is a perspective illustration of an interior
temperature and moisture adjusting device used in an apparatus
according to FIG. 1.
[0035] FIG. 3B shows the adjusting device illustrated in FIG. 3A,
seen in a partially exploded view.
[0036] FIG. 3C is a perspective illustration of the units used for
adjusting the humidity and temperature of the air contained in the
interior of the heat storage cabinet illustrated in FIG. 1.
[0037] FIG. 4 is a perspective illustration of a heat cabinet
according to the invention, provided with a distribution
reservoir.
[0038] FIG. 5 is a simplified perspective illustration of heat
storage according to the invention, provided with several storage
chambers, shown with the cabinet front wall and one of the side
walls removed.
[0039] Let us now deal with the main features of the structures and
functions illustrated in the drawings.
[0040] An apparatus 1 according to the invention, to be used for
the heat storage and/or heating of foodstuffs, is always provided
with one or several adjusting devices 4 formed of water vaporizing
units 2 and an air heating and blowing unit 3 arranged in a storage
chamber 100 of the apparatus. FIG. 1 shows a simplified view of an
apparatus 1 used for the heat storage of food, said apparatus 1
having one chamber and being provided with an adjusting device 4
formed of water vaporizing unit 2 and air heating and blowing unit
3.
[0041] In FIG. 1, there are omitted, among others, the temperature
sensors forming part of the adjusting system 5, which are
illustrated in more detail in FIGS. 2A and 2B. The adjusting system
5 collects monitoring data as regards the temperature and moisture
of the foodstuffs during storage in the heat cabinet 1.
[0042] In cross-section, the heat storage apparatus 1 is a
rectangular heat storage cabinet 1, the length of said cabinet
being L and its width l, said measures being the same as the
lengths L and I of the lengthwise inner walls 1a and the widthwise
inner walls 1b respectively (FIG. 4). FIG. 1 shows the circulations
of air I in the interior T of the apparatus 1; by which
circulations there is created a moisture lock at a desired relative
humidity RH % of air.
[0043] FIG. 4 shows a cabinet 1, similar to the one illustrated in
FIG. 1, to be used in the heat storage of food, where also a food
dispensing arrangement 700 is integrated above the cabinet 1.
[0044] FIG. 5 shows a heat storage cabinet 11; 10 comprising two
heat storage chambers 100; 100a, 100b, in which case at least part
of the chambers 100 are provided with their own adjusting device 4:
4a, 4; 4b comprising a water vaporizing unit 2, an air heating and
blowing unit 3 and a unit for measuring the temperature and
humidity of the interior air. The control systems of different
chambers can be partly or completely integrated, at least as
regards the adjusting unit 52; 52b of the humidity and temperature
of the air contained in the chambers, and the temperature and
humidity data collecting, processing and recording unit 51. This
kind of embodiment of the heat storage cabinet 1; 10 according to
the invention is advantageous, when various different foodstuffs
are stored in one and the same heat storage cabinet, and/or when
the capacity of the heat storage cabinet should be increased. Both
of said features are particularly advantageous, when the storage
cabinet is used as part of a distribution device, or in connection
with it.
[0045] FIG. 1 illustrates the circulation of air generated by this
kind of adjusting unit 4 to the interior T of the device 1, and the
placing of the water vaporizing unit 2 provided in said adjusting
unit with respect to the air blowing and heating unit 3 and the
inner walls and bottom of the device 1. All these factors are
important for the realization of the invention.
[0046] In a heat storage apparatus 1 according to the invention,
the purpose is to create in the interior T of the apparatus a
so-called moisture lock that prevents moisture from evaporating
from the foodstuffs. In order to achieve this aim, on the opposite
lengthwise inner walls 1a of the apparatus, and/or possibly also on
the horizontal inner walls 1b thereof, there is attached a number
of pairs of support beams 8 serving as the supporting frame 60 of
the vertical adjusting device 4 and of the food container vessels
9. The mutual distance D of the support beams 6' and 6'' in each
pair of support beams 8 in the width direction of the apparatus is
generally roughly the same as the length l of the horizontal inner
wall 1b, reduced by the thickness of the support beams 6. In case
the support beams 6 of the pairs of support beams 8 are located on
the opposite lengthwise walls of the heat storage cabinet 1, the
first beam 6' is supported against one lengthwise inner wall, and
the second beam 6'' of the pair of support beams is supported
against the opposite lengthwise inner wall, opposite to the first
beam, so that in between the support beams 6'' and 6'', there can
be attached horizontal guide bars 61. In case the beams 6; 6' and
6; 6'' of the pair of support beams 8 are attached to the
horizontal inner walls 1b, they are installed at the corners of the
horizontal inner wall 1b and the lengthwise inner wall 1a. To
adjacent beams 6' and 6'' of the pairs of support beams 6, there
can be detachably attached a vertical component of the adjusting
device 4, i.e. an air heating and blowing unit 3. In the lengthwise
direction of the apparatus, the mutual distance of two successive
pairs of support beams 8 is d, said distance depending on the types
of equipment fastened to the guide bar/guide bars 61 supported
against each pair of support beams. In between successive pairs of
support beams 8, there can now be arranged the container vessels 9
of foodstuffs S by detachably fastening them to the guide bars of
each pair of support beams. The water vaporizing unit 2 of the
adjusting unit is arranged in the vicinity of the apparatus bottom
or on the bottom P, in between two successive pairs of support
beams 8'' and 8'''. The water vaporizing unit 2 is fastened at the
bottom P or in the immediate vicinity of the bottom, detachably on
the horizontal guide bars 61 of the support beams 6 of the pairs of
support beams 8, by means of a sledge supported against said guide
bars. When the adjusting units 2,3 and container vessels 9 are
detachably fastened to the support beams 6, to the bottom P and/or
to the guide bars 61, they can be detached for instance for the
maintenance or cleaning of the apparatus. In the case of the water
vaporizing unit 2, the water reservoir 23 can be pulled out of the
apparatus along the guide bars 61 and filled with water, wherefore
a separate duct is not needed for the water reservoir. In the
embodiment illustrated in FIG. 1, to the inner walls of the
apparatus, there are fastened four pairs of support beams 8; 8',
8'', 8''', 8''''.
[0047] In the embodiment of the invention illustrated in FIG. 1,
the pair of support beams 8; 8' located furthest on the left-hand
side, and the pair of support beams 8; 8'''' located furthest on
the right-hand side, are fastened to corners left between the
lengthwise and widthwise inner walls 1a, 1b of the apparatus. In
the middle of said pairs of support beams 8' and 8'''', there are
left two pairs of support beams 8; 8' and 8; 8''', which are
fastened in a vertical position to the lengthwise side walls 1a.
The adjacent support beams 6', 6'' of each pair of support beams 8
are located at a mutual distance D in the widthwise direction of
the apparatus. The distance d in between two successive pairs of
support beams in the lengthwise direction of the apparatus is
always the same, and at the same time it also is the distance left
between the guide bars 61' and 61'' attached to the beams of said
pairs of support beams. In between two successive pairs of beams 8'
and 8'', located on the left-hand side in the drawing, there is
arranged a horizontal food container vessel 9 attached to the
horizontal guide bars 61 of the support beams 6 of said pairs of
support beams 8', 8'', near to the bottom P of the heat storage
apparatus. To the horizontal guide bars and support beams of two
successive middle pairs of the support beams 8'' and 8''', there
are connected the units 2 and 3 of the adjusting system 4. Among
said units, the air blowing and heating unit 3 having a vertical
housing 30 is fastened detachably at its vertical edges to the
support beams 6' and 6''. The width of the housing 30 of the air
blowing and heating unit 3 is approximately the same as the width L
of the heat storage apparatus 1, and near the ceiling of the
interior T of the apparatus, it extends towards the vicinity of the
bottom of the apparatus, i.e. the height of said housing 30 is
somewhat lower than the height K of the apparatus 1.
[0048] As can be seen in FIG. 3A, the housing 30 is relatively
short in the dimensions of the longitudinal direction d of the
apparatus. Inside the housing 30, there is room for only part of
the interior air mass I at a time, and said housing conducts said
part of the air mass from the top part T of the interior of the
apparatus to the lower part.
[0049] Thus the heating unit can take in the air to be heated and
circulated from the top part of the apparatus and blow a certain
heated air mass I' from the lower part of the housing 30 of the
unit 3 to the air space T of the apparatus, to the vicinity of the
bottom P of the apparatus. The air vaporizing unit 2 is placed
adjacent to the same pair of support beams 8''' to which the
vertical air blowing and heating unit 3 is connected. The
vaporizing unit 2 can be attached in between successive pairs of
support beams 8'' and 8''' on horizontal guide bars 61 on the
bottom P, as is apparent from FIG. 4, but it can as well be
immersed in the bottom P. At least the water reservoir 23 of the
vaporizing unit is pulled out of the door opening along horizontal
guide bars 61 for cleaning the reservoir and for filling it with
water. FIG. 1 shows an alternative way for placing the vaporizing
unit. The water vaporizing unit 2 can be set underneath the air
blowing and heating unit 3, along the same vertical line V as the
blowing and heating unit 3, but generally it is arranged adjacent
to said line, underneath the lower edge of the blowing and heating
unit 3.
[0050] In FIG. 1, there is drawn the flowing direction of the air
blown from the lower part of the air blowing and heating unit 3
towards the bottom P; part (I') of the air mass (I) located in the
space T proceeds from the lower edge of the housing 30 of said unit
3 towards the bottom P of the apparatus and is directed therefrom,
in the direction of the bottom, towards the inner sides 1a, 1b of
the apparatus, preferably towards the widthwise inner sides 1b. At
the inner sides 1a, 1b at the latest, the air rises upwards and
returns through the top part of the apparatus to the blowing and
heating unit 3. When proceeding near the bottom P, the heated air
flow passes over the horizontally installed water reservoir 23 of
the water vaporizing unit 2 and seizes at the same time along the
aqueous steam that is vaporized in the water reservoir. After the
water reservoir, the air flow proceeds in the direction of the
bottom, until it reaches the food container vessel 9 located
somewhat higher than the bottom. When passing over the vessel 9,
the air flow moisturizes the food S placed in the vessel, thus
preventing it from drying. The above described way for circulating
air, where only part (I') of the air mass (I) contained in the
space T is heated in the housing 30 with closed sides and conducted
from the housing to the water reservoir 23 to be moisturized
immediately before the air reaches the foodstuffs S, brings forth a
particularly advantageous and easily controllable effect in the
food moisture balance: the air proceeding through the housing 30
from top to bottom is heated inside the housing 30 when passing the
resistors 32, so that its relative humidity is reduced. When the
heated air mass reaches the water reservoir 23, its relative
humidity is lower than that of the surrounding, colder air mass, in
which case it absorbs humidity from the water reservoir 23. Thus
the recently moistened air arrives from the vaporizing unit 2 to
the foodstuffs S exactly when it contains a maximum amount of
moisture. Consequently, it can always be assumed that the relative
humidity of the air T in the interior of the apparatus is highest
at the foodstuffs, irrespective of possible openings and closings
of the doors of the apparatus. In case the total air mass I
contained in the space T would be heated, and the air were blown
downwards from top to bottom or sideways as in prior art devices,
the air would be scattered and cooled on the way, and it would be
difficult to control the quantity of water absorbed by it from the
moisturizing reservoir. Moreover, an opening of the apparatus door
would remarkably disturb the air circulation and moisturizing, in
case the whole air mass would be moved by the blowers. In that
case, there would be needed replacement air for balancing the air
circulation.
[0051] The above described controlled feeding of air through a
closed space 30 from the top part of the apparatus to its lower
part, the heating of the conducted air and the targeted way of
circulating the heated air upwards from the bottom on the other
hand ensure that in all conditions, the air circulates along the
shortest possible route from heating and moisturizing to the
foodstuffs. Further, this kind of air circulation ensures an even
temperature and moisture in the whole space T, because the heated
air adjusts the foodstuffs immediately at the temperature and
humidity of the circulated air, and because the heated humid air
has a free access to flow along its natural path upwards from the
bottom. The operation of the adjusting device 4 according to the
invention is highly energy-efficient, because only a part (I') of
the air mass (I) of the interior T of the storage cabinet is being
heated and blown at a time; the ratio of the volume of the interior
of the housing 30 to the volume of the interior T of the whole
apparatus 1 is roughly 1/100-40/100, preferably 4/100-12 1 100. Now
the heating power of the heating resistor 32 and the blowing power
of the blower 31 can be adjusted relatively low in comparison with
the volume of the heat storage cabinet.
[0052] The water vaporizing unit 2 employed as the air moisturizing
unit 2 of the adjusting device 4, as well as the air heating and
blowing unit 3 employed as the air humidity adjusting unit 3, used
in a uni-chambered heat storage apparatus 1 of the invention
according to the FIGS. 1 and 4, are described in FIGS. 3A-3C. The
principal idea of an apparatus 1 according to the invention is to
continuously maintain in the interior T of the apparatus a relative
humidity RH % of air that is roughly on the same level as the
active water contained in the foodstuffs. When heating the
foodstuffs S, the quantity of water evaporated therefrom depends on
the quantity of active water contained in the foodstuffs. In case
the relative humidity in the interior of the heat storage apparatus
is maintained the same as the quantity of active water contained in
the foodstuffs at said temperature, water is not evaporated from
the foodstuffs. The quantity of active water contained by different
foodstuffs at each temperature can be defined either empirically or
on the basis of values obtained from the literature. Preferably the
relative humidity of air is adjusted to be essentially the same as
the quantity of active water contained in the foodstuffs at said
temperature. In case several different foodstuffs should be kept
warm in the heat storage cabinet for serving/distribution, the
moisture in the interior of the device is adjusted at the average
balance moisture of the foodstuffs (=average quantity of active
water) and/or there is used a multi-chambered heat storage
cabinet.
[0053] Specially should be noticed that air is not taken into the
interior of the apparatus 1 from external sources except when the
foodstutffs are taken from inside or brought into inside via
door.
[0054] The adjusting system 5 illustrated in FIGS. 2A and 2B
comprises a processing and recording unit 51 for the temperature
and humidity data of the interior air T and/or for the temperature
and humidity data of the food, such as a computer 51, and a number
of sensors 71, 72 and 73, 74 and displays 75a, 75b and 75c of the
measuring unit 7. The adjusting system also includes processing
logics (not illustrated), an adjusting unit 52; 52b for adjusting
the humidity and temperature of the interior air, and an adjusting
unit 52; 52a for measuring and adjusting the temperature of the
heat bath 9; 9a. FIG. 2B shows a display 7; 75a connected to the
temperature sensors 71 and 72 and to the relative humidity sensor
73 of the adjusting unit 5; 52b. FIG. 2B also shows an adjusting
unit 5; 52a, which adjusts the temperature of the heat bath 9; 9a
by intermediation of an infrared radiator 9; 9b and the temperature
of the heat bath 9; 9a by intermediation of the sensor 7; 74.
Mentioned adjusting unit 52; 52a includes also a display 7; 75c for
indicating the state of the infrared heater 7; 75 and a display 7;
75b for indicating the state of the heat bath 9; 9a.
[0055] FIGS. 2A and 2B show a sensor 71, connected to the adjusting
unit 52; 52b, for taking random samples of the temperature inside
the foodstuff S, and a sensor 72 for measuring the temperature of
the interior air and the sensor 73 the humidity of the interior air
T. The adjusting unit 52; 52b for adjusting the humidity and
temperature of the interior air also includes a display 7; 75a for
indicating the humidity and temperature of the interior air 1 and
of the foodstuffs S. The sensor 73 for measuring the relative
humidity of air is located for example in the lengthwise back wall
1a of the apparatus. The temperature sensors 71 and 72, and the
sensor 73 for measuring the relative humidity of air, monitor the
humidity and temperature values for instance at certain intervals
or continuously, and the data is processed by a computer 51 and
stored for possible control operations to be carried out later. The
sensor 72 for measuring the air temperature is located for example
in the vicinity of the air heating and blowing unit 3, as can be
seen in FIGS. 3A and 3B. On the basis of the temperature and
humidity data obtained from the sensors, the operation of the water
vaporizing unit 2 and the air heating and blowing unit 3 is
adjusted by intermediation of the adjusting unit 52; 52b, so that a
desired temperature and a relative humidity RH % suitable for the
foodstuffs prevails inside the heat cabinet all the time, said
relative humidity being in balance with the active water contained
by the foodstuffs at said temperature T. The adjusting unit 52; 52b
is used for heating the water contained in the water reservoir 23
by a mat resistor 22, and the air flowing in the housing 30 by a
resistor 32 provided in the housing 30.
[0056] Now the temperature sensors 71, 72 are advantageously
connected to an electronic thermostat, in which the temperature can
be accurately controlled. Another alternative is to connect the
temperature and relative humidity sensors 7; 71, 72, 73 to a PDI
adjuster 7; 70 illustrated in FIG. 2A, which PDI adjuster is used
for adjusting the operation of the water vaporizing unit 2 and the
air heating and blowing unit 3. FIG. 2A also shows a quick
connector 36 for detachably connecting a digital temperature
display and temperature sensor (cf. FIGS. 3A and 3B) in the heating
and blowing unit 3 used for reducing the relative air humidity.
Apart from a separate digital temperature display, the system can
also include a separate digital relative humidity display, which is
connected to the sensor 73 measuring the relative humidity in the
interior.
[0057] In a heat storage apparatus according to the invention, for
the heating and blowing of air and for the heating of water, there
is used an adjusting device 4, and the unit 3 for reducing the
relative humidity of air and the air moisturizing unit 2 provided
therein are illustrated in FIGS. 3A-3C. For reducing the relative
humidity of air in the interior T of the heat storage apparatus 1,
i.e. for heating and transferring air, there is used the unit 3.
Said air blowing and heating unit 3, employed for reducing
moisture, comprises a vertical housing 30 that is open at the top
and the bottom, inside which housing there are installed heating
resistors 32 and an air blower 31 that blows air downwards from top
to bottom, past the heating resistors 32. The air sucked inside the
hollow housing 30 through the open top part owing to the operation
of the blower 31 is heated to a desired temperature inside the
housing 30 of the air blowing and heating unit 3 by intermediation
of the resistors 32 placed in the air flow and is discharged,
pushed by the blower 31, through the open lower part of the housing
towards the bottom P located underneath the housing. The air
humidity and temperature adjusting device 4 also includes a water
vaporizing unit 2 employed as the air moisturizing unit and placed
adjacent to the described air blowing and heating unit 3. The air
moisturizing unit 2 includes a horizontal, plate-like housing 20.
The housing 20 has two parts, comprising a shallow water reservoir
23, where at least the bottom is made of some heat conductive
material, such as stainless steel, and an electric connection 25
connected to the lower edge of the water reservoir. The electric
connection 25 must be safe in the humid and warm conditions of the
heat cabinet. In between the bottom P and the water reservoir 23,
there is arranged a heating resistor 22 for indirectly heating
water through the reservoir bottom. Outside the apparatus, in
connection with the interior, there is arranged a digital
temperature display, the sensor 72 whereof is located for instance
in the vicinity of the containers 9 of the foodstuffs S. Said
display obtains temperature readings from the sensor 72 measuring
the interior air temperature.
[0058] FIG. 4 shows a heat storage cabinet 1 according to the above
described FIG. 1, with a distribution equipment 700 integrated
therein. An even temperature and humidity can be maintained inside
the heat storage cabinet by means of the above described adjusting
mechanism irrespective of the fact that the doors are repeatedly
opened and closed. Now on top of the heat storage cabinet 1, in the
same frame with the cabinet, there can be installed a distribution
equipment 700.
[0059] FIG. 5 illustrates yet another embodiment of the invention,
where the heat storage cabinet 1; 10 comprises two adjacent
chambers 100; 100a, 100b in the lengthwise direction of the
apparatus. Each chamber 100 has its own adjusting device 4; 4a and
4; 4b, respectively, said adjusting units being similar as to the
unit 3 meant for reducing the relative humidity of air and as to
the unit 2 meant for moisturizing the air, at least. On the other
hand, some of the elements of the adjusting system 5, such as the
temperature and humidity data collecting, processing and recording
unit 51, and possibly some adjusting unit elements, can be common
for both chambers. On top of the water reservoir of the water
vaporizing unit 2 of the adjusting devices 4 and adjacent thereto,
there are installed food container vessels 9. As can be seen in the
uni-chambered heat storage apparatus illustrated in FIGS. 1 and 4,
also in this bi-chambered heat storage apparatus 1; 10, each
adjusting device 4; 4a and 4; 4b comprises one vertical air heating
and blowing unit 3 and a water vaporizing unit 2 provided with a
horizontal water reservoir. In the middle pair of support beams of
the frame 60 of the heat storage cabinet 11; 10, there is now
installed a partition wall 12 in the widthwise direction of the
apparatus 1 for preventing air from flowing between chambers 100a
and 100b, and between the corresponding adjusting units 4a and
4b.
[0060] By means of the embodiment according to FIG. 5, there can
also be achieved a heat storage apparatus where air heating and
humidity levels in the separate chambers 100; 100a or 100; 100b of
one and the same apparatus 1; 10 are mutually remarkably different,
depending on the food heating requirements and moisture balance
desired in each case. FIG. 5 also shows an advantageous way of
placing the widthwise horizontal guide bars 61 of the apparatus: in
between the horizontal guide bars 61 and the widthwise sides 1b,
there is advantageously left a space where air is free to
circulate.
[0061] In the above specification, only a few embodiments of the
invention have been dealt with, and for a man skilled in the art it
is obvious that the invention can also be realized in many other
ways within the scope of the inventive idea defined in the appended
claims.
[0062] Hence, the heat storage apparatus according to the invention
can be integrated, apart from the distribution device mentioned
above, also in other food serving, preparation and processing
equipment used in restaurants and institutional kitchens. Earlier
this has not been possible, because in known arrangements, the
measurement of temperature and humidity in the interior T has been
unreliable due to a remarkable fluctuation of the temperature and
humidity in the different parts of the interior. However, in the
apparatus according to the application at hand, the humidity and
temperature conditions of foodstuffs in the interior of the
apparatus can be measured reliably with one temperature sensor and
one humidity sensor, because an even humidity and temperature are
obtained at the correct spots in the interior T, i.e. at the
storage locations of foodstuffs, by means of a correct circulation
of air. When said measurements are also combined with foodstuffs
temperature control by a separate sensor, there is achieved a
reliable measurement of the temperature and humidity of the
interior air in the apparatus, which enables an efficient control
and registering of the storage history of foodstuffs.
[0063] The above described integrated apparatuses are unheated or
heated planes formed as the top surfaces of a heat storage
apparatus, heat compresses and warm and neutral plate distribution
equipment, as well as heated and unheated storage shelves and
cabinets supported against the top surface of a heat storage
apparatus. These can also be provided with various different light
fixtures and heat radiators that are placed above the food
distribution, service, preparation and processing equipment
integrated in the heat storage apparatus.
[0064] Advantageously each chamber of the heat storage apparatus
100 is provided with a measuring unit 7, including a thermometer 72
for measuring the temperature of the air in the interior T, and a
humidity meter 73 for measuring the relative humidity. In addition,
the measuring unit also includes an injection thermometer 71 for
measuring the temperature of the foodstuffs S, which thermometer is
located physically outside the apparatus but is connected to an
adjusting unit 52 and to a temperature and humidity data
collecting, processing and recording unit 51 when measuring the
temperature.
[0065] Further, on the guide bars 61 of the heat storage apparatus,
there can be installed, instead of the container vessels 9
described in the exemplary embodiment, for instance detachable
drawers that are appropriately designed with GN measures.
* * * * *