EP0931994A2

EP0931994A2 - A freezer, in particular a commercial freeze box for the display and storage of frozen products

Info

Publication number: EP0931994A2
Application number: EP98610051A
Authority: EP
Inventors: Ole Poulsen
Original assignee: Caravell AS
Current assignee: Caravell AS
Priority date: 1998-01-27
Filing date: 1998-12-23
Publication date: 1999-07-28
Also published as: EP0931994A3; DK11498A

Abstract

A freezer, in particular a commercial freeze box for the display and storage of frozen products and provided with transparent lids (1, 2) in connection with a frame (3), comprises a fan assembly (6) capable of passing a flow of air via a duct (7) across the top side of the lids to prevent possible misting on the top side thereof. Forming the frame (3) with an air duct with air nozzles (10) provides a simpler structure which does not interfere with the appearance of the freezer either. In an embodiment, the duct is formed by the upper part of the frame and a transverse partition in it. This additionally results in a more rigid frame which is easier to handle in the production.

Description

The present invention relates to a freezer, in particular a commercial freeze box for the display and storage of frozen products, e.g. edible ice, and provided with transparent lids in connection with a frame defining the opening of the freezer, and with an incorporated compressor in a compressor compartment intended therefor and communicating with the surroundings.
Under special temperature/air humidity conditions misting may occur on the top side of the glass lid of a chest freezer, which is undesirable because it entirely or partly blocks the view of the contents in the freeze box.
In freezers equipped with a lamp panel on the top side along one side and containing a blower which sends a flow of air down over the glass, the problem of misting is reduced somewhat, but it is not all freezers that are provided with a lamp panel. Furthermore, there is a decreasing effect from the lamp panel toward the other side of the lid. The effect from the lamp panel diminishes additionally in case of inclined boxes, i.e. freezers with an inclined top side which slopes away from the lamp panel, and the effect diminishes additionally when the glass lids are curved.
Glass lids provided with a heat reflecting coating (EP 0 236 286 B1, DE 37 42 693 C2) to reduce the energy consumption of the freezer, remedy the problem to some extent, and the same applies to glass lids provided with thermo-pane glass. The latter, however, are so heavy that the operation is impeded. A solution to remedying misting comprises passing a condenser pipe right up to the upper edge of the side wall of the freezer, right up in the frame. This, however, does not prevent misting of the glass lids in any event, and particularly not if the glass panels are mounted in a plastics frame which breaks the intended heat transfer to the glass panels. Another solution comprises mounting electrical heating elements or decided heating of the glass lids in the form of electrically heated glass, which per se is flagrantly inconsistent with the function of a freezer, and it moreover consumes much energy.
Finally, it is known to pass a flow of air across the outer side of the lids to prevent misting of these. Thus, US 2 542 136 A discloses a refrigerated display case, in which air is conveyed from the compressor compartment via an air duct in the rear side of the case to the upper edge of the sliding lids. Another solution comprises conveying air from the side of the lids horizontally inwardly over these. A somewhat more elegant solution comprises dividing the glass lids into sections by means of bars, which are utilized for conveying the air across the lids. Finally, the air may be conveyed via air ducts to the lower edge of the lids. In US 2 696 087 A, which concerns a freeze box, the air is conveyed from the compressor compartment via an outer duct on the rear side of the freezer up to an air distribution duct on the top side of the freezer. The amount of air and the direction of the air may be adjusted by means of a specially constructed revolving damper. US 4 741 172 A discloses a refrigerated display case in which the air is conveyed from the compressor compartment out on the rear side of the freezer. Side-defining projections and the wall against which the freezer is mounted, define a duct behind the freezer through which the air is passed upwards. At the top side of the freezer, the air is drawn by a fan into a duct defined by the insulation and the top side of the case. The duct conveys the air to the front side of the lids where the duct ends in a plurality of air nozzles. WO 87/3671 discloses a refrigerated display case in which the air is conveyed from the compressor compartment through a duct below the bottom to the lower edge of the glass pane. US 4 949 554 discloses a refrigerated display case in which the air is conveyed from the compressor compartment through an air duct, which extends in the entire front side of the case, and from which the air is passed via a gap upwards over the sliding lids. It is common to these structures that the air is conveyed via separate ducts forwardly to and is distributed along the lids or the panes. The ducts are relatively complicated and affect the structure and the appearance.
The object of the invention is to provide a simpler, but still effective solution to the problem of misting of the lids with a flow of air.
According to the invention, the frame is provided with an air duct with air nozzles to pass the flow of air across the top side of the lids. Particularly, it is possible to produce an air duct at the top of the frame with a horizontal partition in the existing frame profiles, which are typically of extruded aluminium. The transverse wall has the additional advantage that it makes the frame profile more rigid, which is an advantage in the production of the freezers. Another advantage is that the air nozzles, which may quite simply be holes or slots, are quite close to the glass lids, just as the structure does not interfere with the overall appearance and structure of the freezer. Instead of the stated solution, it is possible of course to use separate air ducts embedded in the frame.
In certain freeze box structures, particularly inclined boxes, it has been found to be sufficient to blow out air at the lowest side of the box, and in case of boxes with two sliding lids even only at the lowest lid.
In a further embodiment of the invention, the fan assembly is formed by a fan arranged in the compressor compartment of the freezer and connected with the air duct in the frame. By utilizing the warm air from the compressor compartment the required amount of air may be made correspondingly smaller, which in turn allows a smaller fan to be used, which in turn means that the energy consumption for preventing misting of the lids may be kept down. The energy consumption may be reduced additionally when, in the shops in which the box is installed, the fan is turned off outside regular business hours. The fan may moreover be controlled by a dew point meter, so that the fan starts only when moisture is registered on the glass lids. To prevent impurities from being sucked into the ducts, a filter may be mounted in front of the fan, said filter being expediently arranged so as to be accessible from the outer side of the freezer. It is noted that the positive pressure in the ducts contributes to keeping the blow holes in the ducts clean.
An embodiment of the invention will be explained more fully below with reference to the accompanying drawing.

In the drawing;

Fig. 1 shows a freeze box seen obliquely from behind,
fig. 2 shows a cross-section through the freeze box, and
fig. 3 shows a cross-section through the side wall of the box at the frame.
As will appear from the drawing, the freeze box comprises two sliding glass lids 1, 2 in a frame 3 as a termination of the side walls 4 of the box and additionally defining the opening of the freeze box. A fan 6 is arranged in the ceiling of the compressor compartment 5 of the box, said fan being connected with a pipe 7 to an air duct 8 at the top of the frame 3. The air duct is provided by a horizontal transverse wall 9 in the frame. In addition to defining the air duct 8, the transverse wall has a stiffening effect which makes it easier to handle the profile in the production of the freezer.
The freeze box is a so-called inclined box, i.e. with an inclined opening, it having been found by experience that the problem of misting occurs at the low side of the freezer and only on the lowest glass lid 2.
The frame 3 is provided with a plurality of nozzle holes 10 at the lowest side of the box adjacent the lowest glass lid 2, air being passed from said nozzle holes across the lid. The holes are graduated in size so as to produce an even air flow as an air curtain inwardly across the lid.
The air in the compressor compartment has a higher temperature than the surrounding air because of the waste heat from the compressor. In some situations the temperature may be so high that actual cooling of the compressor with a fan is required.
By utilizing the warm air from the compressor compartment, the glass lid may effectively be kept free from misting on the top side with a relatively modest amount of air. The necessary fan may thus be correspondingly small and not very energy-consuming.
Although the invention has been described above mainly in relation to chest freezers with glass lids, nothing prevents the invention from being applied also in connection with cabinet freezers with glass doors.

Claims

A freezer, in particular a commercial freeze box for the display and storage of frozen products and provided with transparent lids (1, 2) in connection with a frame (3) defining the opening of the freezer, and with an incorporated compressor in a compartment (5) adapted therefor and communicating with the surroundings, and comprising a fan assembly (6) capable of passing a flow of air via a duct (7) across the top side of the lids to prevent possible misting on the top side of these, chararacterized in that the frame (3) is provided with an air duct with air nozzles (10) to pass a flow of air across the top side of the lids.
A freezer according to claim 1, characterized in that the air duct is defined by the upper part of the frame (3) and a horizontal partition (9) in the frame (3).
A freezer according to claim 2, with a frame having two ledges for sliding lids, characterized in that the horizontal partition (9) is positioned at, preferably in extension of the upper ledge.
A freezer according to claim 1, 2 or 3, provided with sliding lids, characterized in that air nozzles (10) are provided on the extent with the lowest sliding lid (2).
A freezer according to claim 4 and of the type having an inclined opening, characterized in that air nozzles (10) are exclusively provided at the lowest side of the freezer.
A freezer according to claim 1 or 2, characterized in that the fan assembly is formed by a fan (6) arranged in the compressor compartment (5) of the freezer and connected with the air duct in the frame.
A freezer according to claim 6, characterized in that the connecting duct (7) from the compressor compartment (5) and the duct in the frame are embedded in the side wall (4) of the freezer.
A freezer according to claim 6, characterized in that the fan (6) is placed in a recess in the insulation in the ceiling of the compressor compartment (5).
A freezer according to claim 1 or 6, characterized in that it comprises a timer for the control of the fan assembly.
A freezer according to claim 1 or 6, characterized in that it comprises a dew point meter for controlling the fan assembly.