This invention relates to a chest freezer or the like comprising a housing containing a freezing and preservation compartment bounded by side walls and having a base wall or base, and able to receive food items to be preserved, at least one closure element being positioned at the upper loading aperture of said compartment, seal elements being associated with said closure element and/or the upper end of the walls of said housing, comprising a fan for providing a forced air circulation within the freezing and preservation compartment and for directing cold air into feed ducts provided within the freezer having, said ducts opening at the surface of the walls bounding the freezing and preservation compartment to enable forced air to flow into this latter, there being provided at least one return duct through which the forced air returns to the fan for its circulation. Freezers of the aforesaid type are known from DE-B-1276664. This patent provides an evaporator which is placed very near to the wall of the freezer, with obvious drawbacks in term of energy saving. Moreover the freezing of food is not very fast and could create problems as far as proper conservation is concerned. The food items are placed in them generally one on another within the freezing compartment so as to occupy as much as possible of the entire space of said compartment.
Although on the one hand this allows a considerable degree of loading of the freezer, on the other hand it results in at least partial obstruction of all passages between the food items and hence the impossibility of even a minimum level of air circulation between them. Consequently, frost forms on the food items, the formed ice possibly "welding" a food item to the adjacent one, with obvious drawbacks.
In addition the ice which forms in the freezing compartment can make it difficult to extract the food items from the freezing compartment and can affect their proper preservation.
Chest refrigerators having a cooling and a fast cooling compartment are also known (see CH-A-345 025).
An object of the present invention is therefore to provide a freezer of the stated type which solves the above technical problems.
A further object is to provide a freezer of the stated type in which the formation of frost on the food items can be prevented.
A further object is to provide a freezer of the stated type in which the food items can be stored in the best possible manner without limiting the capacity of the freezing compartment.
A further object is to provide a freezer of the stated type which is of simple construction, reliable and of simple use.
A further object is to provide a freezer in which at least small quantities of food can be frozen rapidly.
A further object is to provide a freezer in which the freezing compartment can be reduced in size in order to use only a part of its useful volume when the quantity of food items to be frozen is small, hence reducing the operating cost of the freezer.
These objects are attained by a freezer of the stated type, having the features reparted in the appended claim 1.
The present invention will be more apparent from the accompanying drawing, which is provided by way of non-limiting example and in which:
In Figures 1 to 3, a chest freezer is indicated overall by the reference numeral 1 and comprises a housing 2 containing a freezing and preservation compartment 3 bounded by side walls 4, 5, 6, 7; these latter define a loading aperture on which there is a usual closure element 9. The closure element 9 and/or the free ends 4A. 5A, 6A and 7A of said side walls 4, 5, 6 and 7 comprise usual seal elements or gaskets (not shown) for ensuring the necessary air-tightness within the compartment 3.
The housing 2 also comprises a seat 10 for a usual motor-compressor unit (not shown) forming part of the usual refrigeration circuit of the freezer 1, said circuit comprising an evaporator unit 11.
According to the invention, a forced air circulation is provided within the freezing compartment 3. This enables the food items A contained in said compartment to be better preserved and prevents the formation of frost thereon.
To achieve this, a fan 15 is provided in the compartment 3 to draw air from a duct 16 contained within a wall 17 bounding said compartment 3 on one side and on which the evaporator unit 11 is present. The duct 16 opens into a channel 18 which opens into an inlet 19 provided in said wall, said inlet connecting the channel 18 to said compartment 3.
The fan 15 is positioned, together with its motor 20, in a seat 21 which opens on one side 22 into a cavity 23 separated from the compartment 3 by the wall 17.
The cavity 23 acts as a fast freezing compartment, and can be closed by its own upper closure element (not shown) analogous to said element 9, which can be separated from it. The extent of communication between the seat 21 and the cavity 23 can be varied by any known valve means, if this cavity is not to be used for fast freezing.
The fast freezing cavity or compartment 23 communicates with the compartment 3 via feed ducts 24 provided within the freezer housing 2 (for example embedded in or associated with it) and opening via outlets and inlets 25 and 26 respectively into the compartment 3 and into the fast freezing compartment 23 at the upper ends of their bounding walls.
Specifically, at least the outlets or apertures 25 can be of the always open type (such as those of Figures 1 and 2) or can be throttled (manually or automatically by known actuators) by a panel 28 slidable on fixed guides 29 and positioned at a respective aperture 25; alternatively, the freezer 1 can comprise both throttling apertures 25 and always open apertures (as in Figure 3).
To enable the air to circulate below the food items A contained in the compartment 3, this latter comprises a grille 31 in correspondence with its base wall or base 33.
This grille supports the food items A and creates between them and the base 33 a corridor or channel 35 into which the forced air circulating within the compartment 3 can enter; this channel communicates via an aperture 36 with a duct 37 formed within the housing 2 and communicating with said channel 18. The duct 37 also communicates with the compartment 3, advantageously via the aperture 36.
The described freezer is used in the following manner.
When operated, the fan 15 draws air from the duct 16 (arrow F, Figure 1) which cools in flowing around the evaporator unit 11. The cold air is directed by the fan 15 into the fast freezing compartment 23 (arrow G, Figure 1), the cold air passing from here into the channels 24 via the apertures 26.
From the channels 24 the air passes through the apertures 25 and into the compartment 3 (arrow H, Figure 1). A direct connection 50 can be provided between the compartment 23 and the compartment 3 at the seat 21 for the fan 15 to enable cold air to flow from the fast freezing compartment to the compartment 3.
The cold forced air which thus enters the compartment 3 strikes the food items A contained in it and tends to fall to the base 33 of the compartment.
Part of this air is drawn through the channel 18 by the fan 15 (arrow K, Figure 1) whereas a further part reaches the base 33 of the freezing compartment.
At this base, a portion of this air passes (arrow W, Figure 1) into the corridor 35 present below the grille 31, to pass from the aperture 35 to the duct 37, and hence, still drawn by the fan 15, to the channel 18 where it joins the air already passing therethrough.
A further portion of the air present in proximity to the base 33 of the compartment 3 passes (arrow X, Figure 1) directly into the duct 37 and then rises to the channel 18.
The air present therein is then drawn into the duct 16 to hence resume circulation within the freezer.
Advantageously, if only a small quantity of food items are contained in the freezer 1 for freezing, and if the freezer is provided at least with some apertures 25 which can be throttled, these latter are closed (or only some of them are closed) by the respective movable panels 28.
These, because of the usual gaskets carried by them, prevent cold air not required for preserving the food items contained in the compartment 3 escaping from the closed apertures 25. This optimizes the performance of the freezer 1 on the basis of the quantity of food items to be frozen and enables its energy consumption to be reduced, with consequent reduction in its operating costs.
Advantageously a movable panel 93 is provided to vary the volume of the compartment 3 according to the load present in it. The panel 93 can be of the type longitudinally slidable (arrow P, Figure 1) on guides 94 provided on the walls 5 and 7 of the freezer housing 2 or of the type completely removable from and insertable (arrow L, Figure 3) into transverse guides 95 providable at discrete points on said walls.
Consequently, when the quantity of food items A to be preserved is reduced, some apertures 25 can be closed and the compartment 3 reduced in size (continuously or discretely) by the panel 93 (provided with seal gaskets cooperating with the walls 5 and 7 of the compartment 3). Forced air circulation is maintained in this reduced compartment portion, the food items A being placed in this portion.
This results in a considerable energy saving and operating cost for the freezer.
Air circulation within the compartment 3 is achieved in an optimum manner via the apertures 25 positioned (with respect to the figures) above the channel 18 and the recirculation duct 37 (these being in a central position and at the base 33 of the compartment respectively) such that the air contacts all food items A at every level within said compartment.
Moreover, because of the compartment 23 the food items can be frozen in a very short time, after which said food items are transferred to the compartment 3 for long-term preservation.
It should be noted that when the panel 93 on the wall 17 is closed, together with the apertures 25 (as already described), only the fast freezing compartment 23 is used. In this case, to achieve air circulation between said compartment and the seat 21 there is provided within the wall 17 a duct 103 opening into the compartment 23 and into the duct 16 respectively.
In the case under examination, when the panel 93 is in contact with the wall 17, the outlet 19 is closed by this wall.
On that mouth 104 of the duct 103 facing the compartment 23 there is advantageously positioned a movable plate 105 which closes said mouth when the panel is not in the aforesaid position, ie is distant from the wall 17.
The plate 105 can be moved along guides (not shown) on the wall 17 either manually by the user or automatically (for example by a rotary movement about an axis parallel to said wall) by a lever mechanism 106.
Specifically (see Figure 7 in which parts corresponding to those of the previously described figures are indicated by the same reference numerals) the lever mechanism 106 comprises a member or arm 107 movable along guides 108 against a spring 109.
The arm 107 comprises an end 110 arranged to cooperate with the panel 93 when this is lying on the wall 17. This arm carries a pin 113 which cooperates with a bar 114 pivoted at one end 115 to a fixed part 116 of the freezer housing 2. The other end 119 of said bar is fixed to the flap 105.
When the panel 93 reaches the wall 17 it urges the arm 107 against the spring 109 (arrow C, Figure 7). This causes the bar 114 to rotate via its pin 113 about the pivot 115 to thus rotate the flap 105, which moves from a position in which it is parallel to the wall, ie in which it closes the mouth 104, to the position of Figure 7 perpendicular to the wall 17. In this manner it opens the duct 103 to achieve air flow from the compartment 23 to the duct 16.
To create ducts or channels for air circulation between the various layers of food items contained one above another in the compartment 3, there are provided therein support grilles comprising two spaced-apart support regions, on which the superposed food items lie.
This arrangement is shown in Figures 4 to 6. In these figures, parts corresponding to those of the already described figures are indicated by the same reference numerals.
In Figure 4, two superposed layers A1 and A2 of food items are separated by a channel 60 formed between superposed parallel shelves 61 and 62 of grilles 63 (only one of which is shown in Figure 4). The food items A2 are arranged on a first shelf 61, and the food items A1 arranged on the grille 31 touching the second shelf 62.
Each grille 63 present in the compartment 3 is associated with a side wall (for example the wall 4 in Figure 5) and can be removably arranged parallel to the grille 31 positioned on the base 33.
Each grille comprises lateral elements 65 and 66 superposed in pairs and supporting crosspieces 68 and 69 on which the food items A2 lie and against which the food items A1 touch respectively.
The lateral elements 65 and 66 are bent at the opposing ends 63A, 63B of the grid 63 and are arranged to slide in support brackets 70 associated with the side wall 4 of the compartment 3.
The lateral elements 66 comprise projections 71 which cooperate with the brackets 70 and act as a stop in arranging the respective grille 63 parallel to the support wall 4.
Each grille can be arranged either as in Figure 4, ie retracted onto the side wall with which it is associated, or can be arranged parallel to the grille 31 by extracting it (arrow Y, Figure 5) from the brackets 70.
The first arrangement gives access to the food items A1, whereas the second allows the food items A2 to be introduced into the compartment 3 to create between these and the underlying food items the channel 60 which allows the air leaving the apertures 65 to undergo forced circulation through the two layers of food items. In addition, with the second arrangement the grille 63 rests on lateral supports 75 associated with the walls 5 and 7 of the housing 2 of the freezer 1.
Hence in the example shown in Figures 4 to 6, part of the forced cold air entering the compartment 3 via the apertures 25 provided in the compartment side walls is drawn into the duct 18 after passing through the channel of each grille 63 positioned parallel to the grille 31.
Again in this case, described with reference to Figures 4 to 6, there is improved preservation of the food items contained in the freezer, frost is prevented from forming on the food items, and ice is prevented from forming between food items and parts of the freezer such as the walls and grilles.
In both the embodiments shown in the accompanying figures, a suitable sensor (of known type) connected to any known control circuit incorporating said motor-compressor unit will allow automatic defrosting of the compartment 3.