BACKGROUND OF THE INVENTION
This invention relates to a tempering, chilling and freezing room
arrangement according to the preamble of claim 1.
If possible, foodstuffs are stored and transported as frozen so that
their shelf life could be extended and their processing possibilities improved.
Frozen products are defrosted when necessary or brought to a certain temperature,
i.e. tempered, for further processing or retail sale. Chilling of a product means
a treatment in which the temperature of the product is set to -2 °C at a depth
of 1 cm, for example, in which case the product can be handled, e.g. sliced, with
smaller material losses regardless of whether the product is thoroughly frozen
Typically heat-transferring elements which transfer heat to or from
a treating room are used for regulating the temperature of treating rooms, which
allows to influence the temperature of the product to be treated. Heat transfer
is improved by an airflow which is produced into the treating room, which increases
heat transfer to or from the product considerably.
Prior art solutions include large treating units for foodstuffs which
are suitable for freezing or defrosting large amounts of goods, in particular.
However, it is expensive to build and run such units and they also require a lot
of space. In practice it is thus difficult and uneconomical to establish and maintain
a small but efficient unit with equipment for freezing and defrosting foodstuffs.
BRIEF DESCRIPTION OF THE INVENTION
The object of the present invention is to provide an arrangement
which avoids the above-mentioned drawbacks and allows more reliable tempering,
chilling and freezing of a product to be treated by means of a simpler apparatus.
This object is achieved with an arrangement which is characterized in that the
arrangement also comprises an airflow guide element which is arranged above the
product to be treated and guides the produced airflow to a suction duct through
the product to be treated.
The invention is based on the idea that the whole space of a small-sized
room for treating products is utilized by guiding the airflow through the product
by using an adjustable airflow member. In the room the equipment needed for heating
and cooling air and for producing the airflow are placed above the product to be
treated, which allows to make the depth of the container as small and practical
An advantage of the arrangement of the invention is its small size
thanks to which the arrangement is also suitable for use in small food-processing
plants. Despite its small size the arrangement of the invention has a large variety
of uses, and it is particularly suitable for tempering, chilling and freezing products.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in greater detail by means of preferred
embodiments with reference to the accompanying drawings, in which
DETAILED DESCRIPTION OF THE INVENTION
- Figures 1 and 2 illustrate tempering, chilling and freezing rooms according
to some embodiments of the invention.
According to Figure 1, a tempering, chilling and freezing room is
a closed space provided with a door where the purpose is to influence the temperature
of the product to be treated. The room is designed for one or two pallets of the
product 11 to be treated, depending on the structure of the pallet. The width of
the treating space is determined by the fact that enough space should be left for
the airflow to be produced into the room between the product in the room and the
side walls. Depending on the need, the room may comprise one or two thermally insulated
doors. If the room is intended for two pallets, it is often practical to use two
smaller doors rather than one door which is almost as large as the front wall.
The treating room comprises apparatuses 1 and 2 for producing heat
and cold air. The heat-producing apparatus 1 may be for example a louver-like heat
exchanger, which is heated by electric resistance or hot water and which heats
up the air passing through it. The cooling apparatus 2 may be for example a louver
inside of which a suitable refrigerant flows which absorbs heat from the airflow
passing through the louver and discharges the heat outside the space to be cooled
down. When the heat of the airflow absorbs into the refrigerant, the airflow and
thus also the product to be treated cool down.
The heating and cooling elements 1, 2 are placed in a suction duct
6 provided in the upper part of the treating room. The suction duct is defined
by the roof 7, upper parts 8 of the walls and ceiling 5, the room being closed
and made of heat-insulated material. The airflow is produced into the room by
an absorbing blower 4 which sucks air from the suction duct through the heating
and cooling elements. According to one preferred embodiment, the rotational speed
and suction effect of the absorbing blower 4 can be set steplessly. Preferably
a frequency transformer is used for implementing stepless adjustment. The rotational
speed of the short circuit motor and the absorbing blower attached to it can be
adjusted by the frequency transformer. The stepless adjustment of the suction effect
has the advantage that cooling and heating becomes more economical and the variety
of purposes for which the room can be used increases. For example, when the temperature
of the product has reached the set target temperature in tempering, the product
temperature should be maintained at this temperature. The airflow needed for maintaining
a certain temperature is considerably smaller than the airflow used during tempering.
Stepless adjustment also ensures that the product can be set to the desired temperature
On the side opposite to the absorbing blower 4 the edge of the ceiling
5 needed for forming the suction duct does not extend up to the wall, but forms
an opening 9 which connects the room space to the suction duct 6. Air is sucked
from the room space through the opening and through the heating and cooling elements
1, 2 located in the suction duct. Since air is circulated in the room by means
of the suction effect, the flow is distributed evenly through the product 11 to
be treated and thus the temperature of the product also remains even. The article
to be treated is typically packed for example into cartons, which are arranged
so that there are gaps between the boxes along which the air can flow freely. The
gaps can be provided for example by suitable lathing, grids or by another similar
arrangement, which allows to detach the boxes from one another. Uniformity of the
gaps ensures even flow between the boxes.
According to a preferred embodiment of the invention illustrated in
Figure 1 the airflow guide member comprises an adjustable partition wall 10 connected
to the ceiling 5. The partition wall seals the space between the upper part of
the product 11 to be treated and the ceiling 5.The partition wall is positioned
so that the absorbing blower 4 and the opening 9 in the ceiling are on the different
sides of the partition wall, in other words, the partition wall 10 is transverse
to the suction duct 6 in the upper part of the room. Thanks to this arrangement,
the airflow produced by the absorbing blower 4 is forced to pass through the product
to be treated. The adjustable partition wall is dimensioned so that in the lateral
direction the curtain extends from the front edge of the room, i.e. the door, to
the rear edge of the room, in which case the airflow produced into the room cannot
pass along an impractical route. In the direction of the adjustable partition wall
the depth of the room is dimensioned so that a pallet or a similar object just
fits into the room.
The adjustable partition wall 10 functioning as an airflow guide
element is attached to the ceiling 5 from which it extends down to the upper surface
of the product to be treated. The dimension of the partition wall from the top
to the bottom can be adjusted according to the height of the product to be treated.
The structure of the wall is such that the wall can be folded or rolled up or changed
in another similar manner, and thus the height of the wall can be easily changed.
According to an embodiment of the invention, the airflow guide member
consists of a ceiling 5 whose one end can be lowered onto the upper surface of
the product to be treated as illustrated in Figure 2. The ceiling whose one end
can be lowered guides the airflow to be produced through the product to be treated
in the desired manner since one end 17 of the ceiling settles tightly on the upper
surface of the product 11 to be treated. The arrangement according to Figure 2
is particularly suitable when there are for example three or four or more pallets
of the product to be treated.
According to the preferred embodiment of the invention, the ceiling
5 is attached to a machine unit 18 so that one end of the ceiling can be lowered
onto the upper surface of the product to be treated, the machine unit comprising
devices for producing heat and cold air and an apparatus for producing an airflow.
In that case, the ceiling is attached to one edge of the machine unit by means
of a hinge-like joint, and the other end of the machine unit is connected to a
member controlling lowering of one end of the ceiling, the member being preferably
a spindle motor 19. Lowering of one end of the ceiling 5 onto the product 11 to
be treated can thus be controlled reliably. One end of the ceiling can be adjusted
so that it extends to the upper surface of the product to be treated regardless
of the height of the product. If necessary, the room arrangement of the invention
can be arranged to receive several pallets both in the lateral direction and in
the depth direction, in which case the number of machine units 18 can also be increased.
The material of the ceiling is self-supporting, which allows to make the structure
of the ceiling stiff enough without any auxiliary structures.
According to Figure 2, the end of the ceiling may consist of a separate
hinged part which, when lowered onto the upper surface of the product to be treated,
forms a tight covering part which ensures that the airflow passes through the product
to be treated. Even though the partially lowerable ceiling, which functions as
an airflow guide member, does not cover the whole upper surface of the product
to be treated, the produced airflow can be made to pass through the whole product
to be treated due to both the suction effect by means of which the airflow is produced
and the speed of this airflow. When the airflow has been made to pass through one
pallet of the product with a sufficiently high speed in the horizontal direction,
it does not change its direction at other pallets even though these were not covered
by the ceiling.
The room arrangement also comprises sensors by means of which the
temperature of the product 11 to be treated and the room are monitored. The measuring
data are transferred from the temperature sensors to a control device 12 which
in turn controls the blower 4 and the heating 1 or cooling elements 2, depending
on the need. According to an embodiment of the invention, the sensors comprise
three temperature sensors 13, 14, 15, of which two are in the product to be treated
and one is fixed to the suction duct 6. One 15 of the sensors in the product measures
the surface temperature of the product and the other 14 the inside temperature.
The purpose of the sensor 15 measuring the surface temperature is to monitor that
the product is not heated with an excessive amount of heat, which would increase
the surface temperature too much. The sensor 14 to be placed inside the product
shows the inside temperature of the product on the basis of which one knows when
the whole product has reached the desired temperature. Thanks to the even airflow
produced into the suction duct by means of suction, the surface temperature of
the product is substantially the same everywhere in the product, and thus the place
of the sensor 15 can be selected freely. The inside temperature is the same in
the whole product, too, and thus the sensor 14 measuring the inside temperature
can also be positioned freely. The sensor 13 fixed to the suction duct 6 measures
the room temperature. Data on the room temperature can be used for example when
the product is to be kept at a certain temperature.
The temperature-measuring sensors are connected to a control device
12, which may be a microprocessor or a computer which is arranged to monitor the
measurement results and control the heating and cooling devices 1, 2 and the apparatus
4 needed for producing the airflow according to a selected program. Programs are
stored in the memory of the device for the most common uses of the room, such as
tempering, chilling and freezing. The devices in the room automatically carry out
the programs stored in the memory of the control device 12.
According to an embodiment of the invention, in the control device
12 or in connection with it there is a memory device 16 which registers the temperature
history of the product. The temperature history allows to check that the product
has been treated and stored at the temperatures given in the regulations. By means
of the temperature history it can also be shown that any defects in quality of
the product have not been caused by temperatures contrary to the regulations.
It is obvious to a person skilled in the art that the inventive concept
can be implemented in several different ways. Thus the invention and its embodiments
are not limited to the examples described above, but may vary within the scope
of the claims.