Patent Description:
An existing bottom evaporator is horizontally placed, and a cover plate is commonly additionally arranged at an upper portion of the evaporator and an upper portion of a fan so as to partition the evaporator and a freezer compartment. Meanwhile, the cover plate needs to be attached to the evaporator as closely as possible so as to enlarge a usage space of the freezer compartment as large as possible. A thermal insulation layer needs to be arranged below the cover plate so as to guarantee temperature isolation between the evaporator and the freezer compartment. A cover plate assembly of the evaporator is commonly composed of the cover plate and the thermal insulation layer. Prior art document <CIT> discloses a refrigerating apparatus and more particularly a frost-free upright home freezers. While <CIT> teaches an evaporator for a refrigerator and the refrigerator, and the evaporator comprises a plurality of straight pipes arranged in parallel and a plurality of bent pipes used for being communicated with the end parts of the straight pipes so as to form a continuous through evaporation pipe; the two end plates are provided with fixing holes for the evaporation pipes to penetrate through, and are oppositely arranged at the end parts of the two sides of the straight pipe so as to fix the evaporation pipes; the fins are arranged on the straight pipe in a sleeving mode, and the projections of the fins in the extending direction of the straight pipe coincide with the projection of the end plate or are covered with the projection of the end plate; and the upper clamping plates and the lower clamping plates are arranged at the tops and the bottoms of the end plates and the fins correspondingly, so that airflow entering the evaporator penetrates through the gaps between the fins to conduct heat exchange, and the top ends and the bottom ends of the two end plates are provided with connecting parts used for fixing the upper clamping plates and the lower clamping plates correspondingly.

But the above settings will cause a series of problems. Since the cover plate assembly is completely attached to the evaporator, frost blockage is likely to happen after the evaporator is frosted, thereby causing practical refrigeration efficiency of the evaporator to be reduced, a defrosting period to be short, and complete-refrigerator energy consumption to be high. For a bottom evaporator structure, a return air inlet of the freezer compartment is located between a door body and the evaporator. Once frost blockage occurs to the evaporator, a phenomenon of poor air return will be caused, and consequently, an integral refrigeration effect is influenced.

An objective of the present invention is to provide an air-cooled refrigerator with an evaporator at a bottom of a cabinet, which can solve any above problem.

A further objective of the present invention is to improve an air return structure and improve a refrigeration effect of the refrigerator.

Another further objective of the present invention is to improve a cooling chamber structure and reduce a phenomenon of evaporator frosting.

The invention is defined in the independent claim <NUM>.

Specific embodiments of the present invention are described in detail as below by combining drawings, and those skilled in the art will more clearly understand the above and other objectives, advantages and characteristics of the present invention.

Some specific embodiments of the present invention are exemplarily described without limitation in detail by referring to the drawings below. Same reference numerals in the drawings indicate same or similar components or parts. Those skilled in the art should understand that the drawings are unnecessarily drawn to scale. In the drawings:.

<FIG> is a schematic front view of an air-cooled refrigerator with an evaporator at a bottom of a cabinet according to the present invention. <FIG> is a schematic section view of the air-cooled refrigerator shown in <FIG>. The refrigerator commonly may include the cabinet <NUM>, and the cabinet <NUM> includes a shell, a liner and other accessories. The shell is an outer-layer structure of the refrigerator, and protects the whole refrigerator. There may be one or more liners. The liners may be divided into a refrigerating liner, a variable temperature liner, a freezing liner, etc. according to functions, and the specific number and functions of the liners may be configured according to usage requirements of the refrigerator. In the embodiment, the liner at least includes a bottom liner <NUM> commonly being the freezing liner. A compressor compartment <NUM> is limited at the rear of the bottom of the cabinet <NUM>.

The refrigerator in embodiments shown in <FIG> is internally provided with a partition cover plate <NUM>. The partition cover plate <NUM> is transversely arranged in the bottom liner <NUM> and used for dividing an internal space of the bottom liner <NUM> into a cooling chamber <NUM> and a storage space <NUM>, and the cooling chamber <NUM> is located below the storage space <NUM>.

A return air cover <NUM> is arranged at a front portion of the cooling chamber <NUM>, and a top of the return air cover <NUM> is connected to a front end of the partition cover plate <NUM>. The return air cover <NUM> is provided with at least one front return air inlet communicating the cooling chamber <NUM> with the storage space <NUM>, and air needed for heat exchange is provided for the cooling chamber <NUM> by the front return air inlet.

The evaporator <NUM> is in a flat cuboid shape, and is arranged in the cooling chamber <NUM> in a manner of inclining upwards from front to back, where a front portion of a top surface of the evaporator <NUM>, the partition cover plate <NUM> and the return air cover <NUM> define a frost-accommodating space <NUM>, thereby enabling a part of air inflow from the front return air inlet to enter the evaporator <NUM> from the frost-accommodating space <NUM>. An original return air flow deflection angle is changed by the frost-accommodating space <NUM>, so that return air flow preferably flows through the frost-accommodating space <NUM> with low flow resistance and then flows through the evaporator <NUM>, thereby preventing frost of the evaporator <NUM> from influencing the air flow, improving heat exchange efficiency, and further improving a refrigeration effect of the refrigerator.

The refrigerator in the invention further includes a top heating wire <NUM>. The top heating wire <NUM> is at least arranged at the front portion of the top surface of the evaporator <NUM> and configured to provide heat needed by defrosting for the evaporator <NUM>. In some embodiments, the top heating wire <NUM> may be only arranged at the front portion of the top surface of the evaporator <NUM>, thereby facilitating arrangement of the heating wire for centralized defrosting. Thus, a defrosting effect can be improved, and overflow of hot airflow towards the storage space <NUM> can be avoided as well.

In some other embodiments, the top heating wire <NUM> may cover the top surface of the whole evaporator <NUM>, and density of the top heating wire <NUM> is adjusted according to different defrosting heat quantities needed for different positions of the top surface of the evaporator <NUM>. The density of the top heating wire <NUM> arranged close to the front portion of the top surface of the evaporator <NUM> is the highest, and then, the density is sequentially reduced backwards, thereby providing enough heat for the frost-accommodating space <NUM> at the front of the evaporator <NUM>, but the provided heat does not influence normal work of the evaporator <NUM>. Power and actual temperature of the top heating wire <NUM> may be set section by section, and the temperature does not exceed <NUM> Celsius degrees, thereby effectively improving a safety level and guaranteeing a defrosting effect. After a structure of the frost-accommodating space <NUM> is adopted, a frosted position is transferred towards the frost-accommodating space <NUM> from the front portion of the evaporator <NUM>, thereby facilitating centralized arrangement of the heating wire for defrosting. During defrosting operation, heated hot airflow rises, is stopped by the partition cover plate <NUM>, and then is gathered in the frost-accommodating space <NUM>. Thus, the defrosting effect can be improved, and overflow of the hot airflow towards the storage space <NUM> can be stopped, thereby improving a fresh keeping effect.

An evaporator heat preservation part <NUM> is arranged between the partition cover plate <NUM> and the top of the evaporator <NUM>. By means of the evaporator heat preservation part <NUM>, heat losses of the evaporator <NUM> can be reduced, and frosting even freezing of the surface of the evaporator <NUM> can be reduced. Cold energy on a surface of an evaporator <NUM> of a refrigerator in the prior art is likely to be diffused towards a storage space <NUM>, which causes that a temperature of a bottom area of the storage space <NUM> is obviously lower than that of other parts of the storage space <NUM>, and consequently, integral temperature distribution in the storage space <NUM> is uneven. The evaporator heat preservation part <NUM> solves the above problems. When the evaporator <NUM> is defrosted, the evaporator heat preservation part <NUM> can avoid temperature rise of the storage space <NUM> due to heat diffuse, namely, energy losses are avoided, and storage quality is prevented from being influenced.

The evaporator heat preservation part <NUM> is formed by sequentially stacking a plurality of heat preservation layers different in material. The heat preservation layers include a heat preservation foam layer <NUM>, a resin film layer <NUM> and a metal temperature equalization layer <NUM>.

The heat preservation foam layer <NUM> is attached to a lower surface of the partition cover plate <NUM>. The heat preservation foam layer <NUM> is light, has certain structure strength, and is arranged on the lower surface of the partition cover plate <NUM> so as to prevent large objects placed in the storage space <NUM> from impacting on the cabinet <NUM>.

The resin film layer <NUM> is attached to a lower surface of the heat preservation foam layer <NUM>. The resin film layer <NUM> may be set as a polyethylene film (PE film). The polyethylene film is low in specific weight and easily performs cover. The polyethylene film can be closely attached to the upper or lower heat preservation layer after shrinkage, thereby tightly connecting the heat preservation layers being high in integrality and not prone to separation. The polyethylene film is non-toxic, harmless, waterproof, bacteria-proofing, durable, and suitable for a service environment of the refrigerator.

The metal temperature equalization layer <NUM> is arranged on an outer side of the resin film layer <NUM> and is opposite to the top of the evaporator <NUM>. The metal temperature equalization layer <NUM> may be set as aluminum foil. The aluminum foil is high in ductility, which can reduce a thickness of the metal temperature equalization layer <NUM> to the maximum degree and prevent an internal space of the refrigerator from being occupied excessively; and the aluminum foil is excellent in heat-conducting property, thereby equalizing the temperature of the top of the evaporator <NUM>, and solving a problem about uneven temperature distribution of the storage space <NUM> above the evaporator <NUM>.

The evaporator heat preservation part <NUM> includes a filling portion <NUM> and a heating wire limiting portion <NUM>. An area, located behind the frost-accommodating space <NUM>, between the partition cover plate <NUM> and the top surface of the evaporator <NUM> is filled with the filling portion <NUM>. The heating wire limiting portion <NUM> extends forwards from the filling portion <NUM> and is provided with at least one downwards-protruding convex rib <NUM> which can tightly press the top heating wire <NUM> on the top surface of the evaporator <NUM>. A plurality of convex ribs <NUM> are located above a transverse middle portion and two transverse sides of the top heating wire <NUM> respectively to fix the top heating wire <NUM> more stably.

The heating wire limiting portion <NUM> is made into an E-shaped structure to limit a middle portion of the top heating wire <NUM> at the top surface of the evaporator <NUM>. The metal temperature equalization layer <NUM> is arranged in the evaporator heat preservation part <NUM> and makes contact with the top heating wire <NUM>, which can effectively transfer energy and prevent a local temperature of the top heating wire <NUM> from being too high. The above settings simplify a limiting structure of the top heating wire <NUM>, and the top heating wire <NUM> is fixed only through the evaporator heat preservation part <NUM> without additionally arranging an aluminum plate, thereby improving safety, simplifying the structure and facilitating installation.

A bottom wall of the bottom liner <NUM> is further provided with a water receiving trough <NUM>, and a bottom of the water receiving trough <NUM> is provided with a water outlet <NUM>. The water outlet <NUM> guides defrosting water generated after defrosting into an evaporation dish <NUM> in the compressor compartment <NUM>.

The air-cooled refrigerator may further include a water pan <NUM>. The water pan <NUM> is arranged between the evaporator <NUM> and the bottom wall of the bottom liner <NUM> and configured to receive water on the evaporator <NUM>; and an area, opposite to the water receiving trough <NUM>, of the water pan <NUM> is provided with a plurality of through holes used for guiding the defrosting water generated after defrosting into the water pan <NUM>.

The refrigerator in the embodiment further includes a bottom heating wire <NUM>. The bottom heating wire <NUM> is coiled between the water pan <NUM> and the evaporator <NUM> and configured to provide heat for defrosting of the evaporator <NUM>. The bottom heating wire <NUM> further includes: a front extension section <NUM> which extends to a position in front of the evaporator <NUM> from the bottom of the evaporator <NUM> and is used for heating and melting away frost falling down from the frost-accommodating space <NUM> during defrosting. In a defrosting process, the frost falling down from the frost-accommodating space <NUM> is melted away through the front extension section <NUM> of the bottom heating wire <NUM>. The bottom heating wire <NUM> and the water pan <NUM> are fixed together, which can guarantee uniform heat transfer; and the water pan <NUM> may also have a safety protection function in a transportation process. Power density of the front extension section <NUM> does not exceed 10w/m due to less heat needed at the position, thereby effectively improving the safety level according to the design.

Power of the bottom heating wire <NUM> and the top heating wire <NUM> is designed according to needs, which can guarantee the defrosting effect and meanwhile reduce energy waste and temperature rise of a freezer compartment, thereby improving the fresh keeping effect of the freezer compartment.

The return air cover <NUM> in the embodiment is provided with a first front return air inlet <NUM> and a second front return air inlet <NUM>. The first front return air inlet <NUM> is transversely formed in an upper portion of the return air cover <NUM>. The second front return air inlet <NUM> is transversely formed in a lower portion of the return air cover <NUM>, so that air in the storage space <NUM> flows towards the evaporator <NUM> from an upper area and a lower area.

The return air cover <NUM> may include a first board <NUM>, a second board <NUM>, a third board <NUM>, a fourth board <NUM>, a fifth board <NUM> and a frame <NUM>.

The first board <NUM> extends obliquely downwards from back to front from the front end of the partition cover plate <NUM>. The second board <NUM> extends obliquely downwards from front to back from a front end of the first board <NUM> to be concaved in a direction towards the cooling chamber <NUM>.

The first front return air inlet <NUM> is formed in the second board <NUM>. The first front return air inlet <NUM> is formed by grid holes formed in the second board <NUM>. A structure of a return air cover <NUM> in the prior art is likely to cause uneven return air volume distribution, airflow gathering nearby a return air inlet (e.g., a front end of an upper cover of the return air cover and an internal bending position of the upper cover of the return air cover), thus influencing air return efficiency. The second board <NUM> of the return air cover <NUM> in the embodiment inclines inwards, and thus, a set position of the first front return air inlet <NUM> extends in a direction towards the cooling chamber <NUM>. When flowing through the first board <NUM>, the airflow can be downwards guided due to downward inclination of the first board <NUM>. When flowing through a corner towards an interior of the cooling chamber <NUM> formed by the first board <NUM> and the second board <NUM>, the airflow may evenly flow into the cooling chamber <NUM> along with vortexes in the corner, thereby avoiding situations of uneven air volume distribution and gathering, improving air return efficiency and making air return smoother. A grid is formed at the front return air inlet. The grid holes are in a vertical strip shape and are sequentially distributed in a transverse direction to disperse return air, thereby enabling the return air to more evenly enter an upper section of the evaporator <NUM>. The first front return air inlet <NUM> is basically flush with the top surface of the evaporator <NUM> in a vertical direction so that airflow entering the cooling chamber <NUM> from the first front return air inlet <NUM> can evenly exchange heat with the evaporator <NUM>. The frost-accommodating space <NUM> is arranged at the front portion of the evaporator <NUM>, which changes the original return air flow deflection angle, so that the airflow preferably flows through the frost-accommodating space <NUM> with low flow resistance and then flows through the evaporator <NUM>, and thus airflow heat exchange in the evaporator <NUM> is more uniform. Setting a reasonable size of the frost-accommodating space <NUM> according to simulated analysis and frosting amount calculation can balance usage efficiency of the evaporator <NUM> before and after defrosting, thereby integrally improving the refrigeration effect.

Air, outside the cabinet <NUM>, inflowing from the first front return air inlet <NUM> is frosted in the frost-accommodating space <NUM> after making contact with the cold surface of the evaporator <NUM>; and the top heating wire <NUM> arranged on the top surface of the evaporator <NUM> provides enough heat for the frost-accommodating space <NUM> at the front portion of the evaporator <NUM> for defrosting, but the provided heat does not influence normal work of the evaporator <NUM>.

The third board <NUM> extends obliquely downwards from back to front from a rear end of the second board <NUM> to protrude forwards. The fourth board <NUM> extends obliquely downwards from front to back from a front end of the third board <NUM> to be concaved in a direction towards the cooling chamber <NUM>. The fifth board <NUM> downwards obliquely extends backwards from a rear end of the fourth board <NUM>.

The second front return air inlet <NUM> is formed between the fifth board <NUM> and the frame <NUM>, and is basically flush with a middle portion of the evaporator <NUM> in the vertical direction so that airflow entering the cooling chamber <NUM> from the second front return air inlet <NUM> can evenly exchange heat with the evaporator <NUM>.

The air-cooled refrigerator in the embodiment may further include an air duct back plate <NUM>. The air duct back plate <NUM> is arranged in front of a rear wall <NUM> of the bottom liner <NUM> and defines, with the rear wall <NUM> of the bottom liner <NUM>, an air supply duct <NUM>; and the air duct back plate <NUM> is provided with at least one air supply port <NUM> used for communicating the air supply duct <NUM> with the storage space <NUM>. The air duct back plate <NUM> may be further provided with water retaining ribs <NUM>. The water retaining ribs <NUM> may be arranged on one side, towards a storage compartment, of the air duct back plate <NUM>. Since the airflow contains part of condensate water, the condensate water can be attached to a surface of the air duct back plate <NUM> when the airflow encounters the air duct back plate <NUM>, and the water retaining ribs <NUM> can reduce a falling speed of the condensate water to make all the condensate water evaporate as much as possible, and prevent the condensate water from falling into a fan cavity and causing faults. In the embodiment, transverse extension may refer to horizontal extension and may also be understood that the water retaining ribs <NUM> have a certain inclination angle. The two above manners both can reduce the falling speed of the condensate water on the water retaining ribs <NUM>.

A refrigeration fan <NUM> of the refrigerator in the embodiment is arranged behind the evaporator <NUM>, an air outlet <NUM> of the refrigeration fan <NUM> is connected to a lower end of the air supply duct <NUM>, and the refrigeration fan <NUM> is configured to promote formation of a refrigeration airflow which flows into the evaporator <NUM> from the front return air inlets and then is supplied to the air supply duct <NUM>. In an embodiment in which a centrifugal fan is used as the refrigeration fan <NUM>, the centrifugal fan may include a fan bottom shell <NUM>, fan blades <NUM> and a fan upper cover <NUM>. An air inlet of the centrifugal fan is commonly located in a center of the fan upper cover <NUM> and may be higher than a top end of the evaporator <NUM> to enlarge an air inlet space. The fan upper cover <NUM> and the air duct back plate <NUM> belong to a single-layer board formed through integrated injection molding, thereby simplifying installation steps.

In the air-cooled refrigerator with the evaporator <NUM> at the bottom of the cabinet <NUM> in the embodiment, the front portion of the top surface of the evaporator <NUM>, the partition cover plate <NUM> and the return air cover <NUM> define the frost-accommodating space <NUM>, thereby enabling a part of air inflow from the front return air inlets to enter the evaporator <NUM> from the frost-accommodating space <NUM>. The original return air flow deflection angle is changed by the frost-accommodating space <NUM>, so that the return air flow preferably flows through the frost-accommodating space <NUM> with low flow resistance and then flows through the evaporator <NUM>, thereby preventing frost of the evaporator <NUM> from influencing the air flow, improving heat exchange efficiency, and further improving the refrigeration effect of the refrigerator.

Furthermore, the top heating wire <NUM> is arranged at the front portion of the top surface of the evaporator <NUM>. By means of the frost-accommodating space <NUM>, the frosted position is transferred into the frost-accommodating space from the front portion of the evaporator <NUM>, and the top heating wire <NUM> is arranged at the front portion of the top surface of the evaporator <NUM> in a centralized manner, thereby preventing heat of the heating wire from influencing refrigeration work of the evaporator <NUM> during defrosting, optimizing a defrosting structure of the refrigerator, further improving the refrigeration efficiency of the refrigerator, and reducing energy consumption.

Claim 1:
An air-cooled refrigerator (<NUM>) with an evaporator (<NUM>) at a bottom of a cabinet, comprising:
the cabinet with a bottom liner (<NUM>);
a partition cover plate (<NUM>) transversely arranged in the bottom liner (<NUM>) and used for dividing an internal space of the bottom liner (<NUM>) into a cooling chamber and a storage space, wherein the cooling chamber is located below the storage space;
a return air cover (<NUM>) arranged at a front portion of the cooling chamber, wherein, a top of the return air cover (<NUM>) is connected to a front end of the partition cover plate (<NUM>), the return air cover (<NUM>) is provided with at least one front return air inlet that communicates the cooling chamber with the storage space, and air needed for heat exchange is provided for the cooling chamber through the front return air inlet; and
the evaporator (<NUM>), wherein the evaporator (<NUM>) is in a flat cuboid shape, and is arranged in the cooling chamber in a manner of inclining upwards from front to back, and a front portion of a top surface of the evaporator (<NUM>), the partition cover plate (<NUM>) and the return air cover (<NUM>) define a frost-accommodating space, thereby enabling a part of air inflow from the front return air inlet to enter the evaporator (<NUM>) from the frost-accommodating space,
characterized by further comprising:
a top heating wire (<NUM>) at least arranged at the front portion of the top surface of the evaporator (<NUM>) and configured to provide heat needed by defrosting for the evaporator (<NUM>), and
an evaporator heat preservation part (<NUM>) arranged between the partition cover plate and a top of the evaporator, which comprises:
a filling portion (<NUM>) with which an area region, located behind the frost-accommodating space, between the partition cover plate (<NUM>) and the top surface of evaporator (<NUM>) is filled; and
a heating wire limiting portion (<NUM>) extending forwards from the filling portion (<NUM>) and provided with at least one downwards-protruding convex rib (<NUM>) which can tightly press the top heating wire (<NUM>) on the top surface of the evaporator (<NUM>).