The present invention relates to a refrigerator and a method for operating same. The refrigerator encompasses two movably connected housing parts, a carcass and a door, which jointly delimit a heat-insulated interior space, and also a seal fastened to a first of the housing parts which seal makes airtight contact with the other, second housing part in the closed position of the two housing parts. For the purposes of pressure equalization between an external atmosphere surrounding the refrigerator and the interior space of the refrigerator, the airtight contact between the seal and the second housing part is prevented for a period along part of the seal length in the closed position of the two housing parts in a method step (a). The invention also relates to a refrigerator for carrying out the method. This encompasses a lifting element, which allows an impermeable contact between the seal and the second housing part in a first position and can be transposed into a second position in which it lifts the seal along part of its length away from the second housing part in the closed position of the two housing parts for the purposes of enabling pressure equalization between the interior space and an external atmosphere surrounding the refrigerator.
An operating method of this type and refrigerator is known from DE 36 02 200 A1. In this case, a lifting element 14, 15 realized on a handle 13 engages in a fold 8 of a magnetic door seal 4. Pulling on the handle 13 lifts the magnetic door seal 4 along part of its length away from a contact margin on the carcass of the refrigerator, with the result that a flow path for air is created. A partial vacuum in the refrigerator, which can arise, for example, if warm air enters the interior space of the appliance upon the opening of the door and cools in there following a closing of the door, should therefore be dissipated immediately prior to the actual opening of the door. A partial vacuum prevailing in the interior space of the refrigerator is disadvantageous since it makes it considerably more difficult to open the door. Since the user has to displace the handle 13 over a specific distance for the purposes of operating the lifting element 14, 15 and the pressure equalization between the environment and the interior space of the refrigerator needs a certain amount of time, the actual opening operation of the door is delayed.
The object of the present invention is to provide an operating method for a refrigerator and a refrigerator for carrying out the method, in which the build-up of a partial vacuum, which hinders opening of the door, in the interior space of the refrigerator is prevented.
The object is achieved with the aid of a method as claimed in claim 1 and a refrigerator as claimed in claim 7. The dependent claims relate to preferred configurations.
Accordingly, a method is provided for operating a refrigerator which has two movably connected housing parts, a carcass and a door, which jointly delimit a heat-insulated interior space, and also a seal fastened to a first of the housing parts which seal makes airtight contact with the other, second housing part in the closed position of the two housing parts, the method encompassing a step (a) in which the airtight contact between the seal and the second housing part is prevented for a period along part of the seal length in the closed position of the two housing parts. According to the invention, the step (a) is effected in temporal conjunction with a closing of the door, preferably immediately after its closing, the sealing contact between the seal and the second housing part along said part of the seal length being restored subsequently in a step (b).
An air path between the environment of the refrigerator and the interior space of the refrigerator is therefore created following a closing of the door or preferably maintained upon the closing of the door so that air can flow in from the environment into the interior space of the refrigerator for pressure equalization. This prevents the build-up of a partial vacuum which would hinder a renewed opening of the door shortly after the closing. To open the door, the user only has to overcome the closing force of the magnetic seal used as a rule. To keep cold losses and therefore energy losses as low as possible, the sealing contact between the seal and the second housing part is restored as soon as a pressure equalization has essentially taken place. The time required for this, typically of about five seconds to a minute, is easy to determine experimentally. By particular preference, the airtight contact between the seal and the second housing part after a closing of the door is prevented for about five seconds to 25 seconds along part of the seal length in method step (a).
A refrigerator for carrying out the method described in the foregoing is also provided in accordance with claim 7. This encompasses a lifting element which allows an airtight contact between the seal and the second housing part in a first position and can be transposed into a second position in which it lifts the seal along part of its length away from the second housing part in the closed position of the two housing parts for the purposes of enabling a pressure equalization between the interior space and an external atmosphere surrounding the refrigerator. According to the invention, the refrigerator has a drive unit for the lifting element and also a control device which, after capturing an operation of the door, triggers the drive unit of the lifting element for the purposes of lifting the seal. The force necessary for lifting the seal does not therefore have to be applied by a user of the refrigerator and can be effected irrespective of an operation of a door handle.
Preferably, the seal is pressed away from a contact surface for the seal on the second housing part by means of the lifting element. The lifting element therefore exerts a pressure on the seal for the purposes of lifting the seal away from its contact surface on the second housing part.
Preferably, the lifting element is arranged in a recess of the second housing part in its first position and rises at least partly above the contact surface for the seal on the second housing part in its second position. In the recess, the lifting element is protected from external influences in an advantageous manner. Due to the sunken arrangement in the recess, the lifting element is not visually conspicuous on the refrigerator so that this also represents an aesthetic solution which is also inexpensive due to the simple construction.
The lifting element is preferably formed at least partly from a temperature-dependent deformable material, for example a bimetal or a shape memory alloy. Heating or cooling changes the form or shape of these materials. This change of form or shape can then be utilized in such a way that the lifting element allows an impermeable contact between the seal and the second housing part in a first form and lifts the seal away from the second housing part along part of its seal length in a second form into which it can be transposed by means of heating or cooling. In this respect the first form corresponds to the first position of the lifting element referred to in the foregoing and the second form the second position of the lifting element stated in the foregoing. The lifting element therefore just needs to be cooled or heated to lift the seal.
Preferably, a change of form of the lifting element from its first form into its second is caused by heating of the lifting element. The refrigerator therefore preferably has, as the drive unit for the lifting element, a heating device such as a PTC heating element with the aid of which short heating times can be implemented. Alternatively, it is also conceivable, however, to heat the lifting element by means of ambient air which flows past the lifting element upon the opening of the door. In this case, it is then necessary for the lifting element to possess its second form at normal room temperature, in particular in the range from roughly 15° C. to roughly 35° C. It would also be conceivable for the heating device to be connected to a frame heating system of the refrigerator, which is present as a rule, so that the frame heating system is utilized as the heat source for heating the lifting element.
Alternatively, the lifting element can also be realized as a simple actuator made from, for example, a non-temperature-dependent deformable material which is brought from its first position into its second or vice versa by means of a mechanical, electrical or magnetic drive unit. The lifting element can be realized in the form of a linear actuator, for example.
Preferably, the control device encompasses a switch which, upon an opening or closing of the door, i.e. a movement of the door relative to the carcass of the refrigerator, is changed over and triggers the drive unit for the lifting element. This ensures that after every time that the door stands open, a pressure equalization operation takes place by means of lifting of the seal so that a partial vacuum, which hinders a subsequent opening of the door, cannot be formed in the interior space of the refrigerator. Preferably, the switch comprises the door switch, which is present in every refrigerator as a rule, for operating an interior space illumination. But it may also comprise a door switch that is separate from the interior space illumination.
Preferably, the drive unit for the lifting element, that is to say the heating device for heating the lifting element in the case of the lifting element formed at least partly from temperature-dependent deformable material, is switched on upon an opening of the door. As a result of this, the lifting element takes up its second form or second position in which it protrudes above the contact surface for the seal on the second housing part. If the door is then closed, the lifting element holds the seal lifted, along part of its length, away from the second housing part and releases an air path for air flowing into the interior space with the result that the build-up of a partial vacuum, which hinders an opening of the door, in the interior space of the refrigerator is prevented. Upon a closing of the door, the heating device is preferably switched off. The lifting element cools down slowly but remains in its second form for a certain period after the closing of the door before it reverts to its first form again after the cooling. The pressure equalization can take place during this period.
In the case of the lifting element realized in the form of a simple actuator, the possibility exists, for the purposes of returning the lifting element from its second position to its first, of providing a timer which is activated after a closing of the door and triggers the drive unit of the lifting element after the expiry of a predetermined period of time and brings about a return of the lifting element to its first position.
The inventive refrigerator may comprise a refrigerator or frozen food storage appliance.
Developments and advantages of the present invention are explained in the following on the basis of embodiments of the present invention. In this respect, the diagrams show:
In the heat-insulating wall 6 on the bottom of the carcass 1, a lifting element 7 is arranged in a recess 8. The lifting element 7 is formed in a single piece from a temperature-dependent deformable material such as a shape memory alloy or a bimetal. Underneath the lifting element 7, a heating device 10, in this case a PTC heating element 10, is arranged in the recess 8, which heating device is used for heating the lifting element 7.
A groove 17 is formed in an edge area of the internal wall 14 in which a head section, which is provided with a retaining hook, of the magnetic seal 4 is latched. The magnetic seal 4 possesses a plurality of elongated chambers which lend it flexibility and of which one chamber, which is designated with the reference number 18, is filled with a magnetic material which holds a sealing surface of the magnetic seal 4 pressed against the contact surface 5 realized out of sheet metal.
In
The change of position of the lifting element 7 from its first position shown in
As shown in
Upon the closing of the door 2, the switch 31 is operated once again and the heating element 10 switched off. It cools down together with the lifting element 7 which then, after a specific period of time, reverts to its first form in which it allows an impermeable contact between the previously lifted part of the magnetic seal 4 and the contact surface 5. The lifting element 7 or the heating element 10 are designed in such a way that the magnetic seal 4 remains open for a period of time of roughly 5 seconds to a minute after the closing of the door 2, that is to say a period of time in which a pressure equalization has essentially taken place. This prevents a partial vacuum which hinders the opening of the refrigerator door 2. In the case of a subsequent opening of the door 2, the user just has to overcome the magnetic force which acts between the magnetic material and the metal contact surface 5.
By way of divergence from the arrangement shown in
The lifting element 7 is now described in detail in terms of its construction and its mode of functioning on the basis of the following schematic
Transverse to the magnetic seal 4, the lifting element 7 only extends along part of its width but over the entire width of the chamber 18 which contains a magnetic material. As a result, it is not the overcoming of a magnetic force but just a partial deformation of the magnetic seal 4 that is required to lift the magnetic seal 4 in the area of the lifting element 7 in the event that the magnetic seal 4 were in contact with the contact surface 5 briefly after a closing of the door 2. The lifting element 7 and therefore also the recess 8 extend beyond the edge of the magnetic seal 4 on the sides of the chamber 18 with the result that the lifting element 7 has a freestanding section 20 which is not covered by the magnetic seal 4 in the closed condition of the door 2. This enables a convective heat exchange between the lifting element 7 and the external atmosphere surrounding the refrigerator or the air in the interior space 3 of the refrigerator and therefore a rapid cooling of the heated lifting element 4. By way of divergence from the arrangement shown in
As
Alongside the embodiment described with reference to
The closing of the door 2 also activates, by way of the switch 31, a timer 32 which deactivates the coil 40 after the expiry of a predetermined period of time with the result that the lifting element 37 reverts to its first position again and the magnetic seal 4 makes airtight contact with the contact surface 5. The period of time over which a pressure equalization should be made possible between the interior space 3 and the environment of the refrigerator after a closing of the door can therefore be established precisely. Usually, time periods of 5 seconds to a minute are specified.
By way of divergence from the control system described in the foregoing, it is also possible to bring the lifting element 37 into its second position as early as upon an opening of the door 2 so that the lifting element 37 already takes up its second position in the case of an open door 2, i.e. prior to the subsequent closing of the door 2. This ensures that air can flow into the interior space 3 immediately after a closing of the door 2 and therefore no time delays of any kind occur which, even if only briefly after a closing of the door 2, could cause a partial vacuum to arise. In this control variant also, the timer 32 is not triggered until a closing of the door 2 to ensure that the magnetic seal 4 remains open for a predetermined period of time after the closing of the door 2.
Number | Date | Country | Kind |
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10 2005 021 587.4 | May 2005 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2006/061160 | 3/30/2006 | WO | 00 | 10/15/2007 |