Rotary-drum laundry dryer

Abstract

 Rotary-drum laundry dryer (1) comprising an outer casing (2) having a front wall (2a) and a rear wall (2b), a rotatable drum (3) which is structured for housing the laundry to be dried and is fixed in axially rotating manner inside the casing (2), and a hot-air generator (6) structured to circulate a stream of hot air (f) through the rotatable drum (3); said rotatable drum (3) comprising a substantially cylindrical, tubular body (3) having its front rim (3f) faced to the front wall (2a) of the casing (2) and its rear rim (3r) faced to the rear wall (2b) of the casing (2); the rear wall (2b) of the casing (2) comprising an inner section (13) and an outer section (14) that form/delimit in between themselves a inner cavity (15) which is fluidly connected to the hot-air generator (6); a central portion (13c) of the inner section (13) of the rear wall (2b) being furthermore permeable to air, so as to put the inside of tubular body (3) in communication with the inner cavity (15); the rotary-drum laundry dryer (1) being characterized in that the rear wall (2b) of the casing (2) furthermore comprises an air-deflector member (22) which is fitted/ housed into the inner cavity (15) of the rear wall (2b) and is shaped/structured so as to channel the stream of hot air (f) that enters into the inner cavity (15) towards the permeable-to-air central portion (13c) of the inner section (13) of the rear wall (2b) or vice versa, while at same time keeping said stream of hot air (f) away from the peripheral border of said inner cavity (15).

Description

[0001] The present invention relates to a rotary-drum laundry dryer.

[0002] In particular, the present invention relates to a rotary-drum home laundry dryer to which the following description refers purely by way of example without implying any loss of generality.

[0003] As is known, rotary-drum home laundry dryers currently on the market generally comprise: a substantially parallelepiped-shaped, outer boxlike casing structured for resting on the floor; a substantially cylindrical rotatable drum which is structured for housing the laundry to be dried and is housed in axially rotating manner inside the casing to rotate about an horizontally-oriented longitudinal reference axis, facing a laundry loading/unloading opening formed in the front wall of the casing; a porthole door hinged to the front wall of the casing to rotate to and from a closing position in which the door rests completely against the front wall of the casing to close the laundry loading/unloading opening and airtight seal the rotatable drum; an electrically-powered motor assembly which is housed inside the casing and is structured for driving into rotation the rotatable drum about its longitudinal reference axis; an open-circuit or closed-circuit, hot-air generator which is housed inside the casing and is structured to circulate inside the rotatable drum a stream of hot air which has a very low moisture content and flows through the rotatable drum and over the laundry inside the drum to rapidly dry the laundry; and an electronic central control unit which controls both the motor assembly and the hot-air generator to perform, on command, one of the user-selectable drying cycles stored in the same central control unit.

[0004] Furthermore, in most of the rotary-drum home laundry dryers currently on the market, the rotatable drum consists in a substantially cylindrical, rigid tubular body generally made of metal material and which extends substantially horizontally inside the boxlike casing, aligned to the laundry loading/unloading opening, and is structured for resting on a number of idle supporting rollers which are arranged at the two axial ends of the tubular body parallel to the drum longitudinal reference axis, and are fixed to the appliance casing in free rotatable manner so as to allow the tubular body to rotate about its horizontally-oriented longitudinal reference axis. The circular front rim of the tubular body abuts against the front wall of the boxlike casing so as to surround the laundry loading/unloading opening, and is coupled in axially rotating manner to said front wall; whereas the circular rear rim of the tubular body abuts against the rear wall of the boxlike casing and is coupled in axially rotating manner to said rear wall.

[0005] The stream of hot air produced by the hot-air generator generally enters into the tubular body through an intake air-vent realized in the rear wall of the boxlike casing, within the perimeter of the rear rim of the tubular body, flows inside the tubular body for the entire length of the latter, and comes out of the tubular body through an escape air-vent usually realized on the annular frame that delimits the laundry loading/unloading opening on the front wall of the casing.

[0006] To avoid air leakages from the two axial ends of the tubular body, a first circular sealing gasket is generally interposed between the front rim of the tubular body and the front wall of the casing, whereas a second circular sealing gasket is generally interposed between the rear rim of the tubular body and the rear wall of the appliance casing.

[0007] For holding down the overall production costs of the household appliance, in a few models of laundry dryer currently on the market the intake air-vent of the hot-air generator is arranged approximately at centre of the rear rim of the tubular body and communicates with a inner cavity which is formed inside the rear wall of the casing during assembly of the laundry dryer, coaxial with the rear rim of the tubular body. This inner cavity, in turn, communicates with the hot-air generator near to its peripheral border, so that the stream of hot air produced by the hot-air generator is obliged to flow through the inner cavity before reaching the intake air-vent and flooding into the tubular body.

[0008] This structure furthermore allows to significantly hold down the overall thickness of the rear wall of the casing.

[0009] Despite allowing a significant containment of the overall production costs of the laundry dryer and a slim rear wall, unfortunately the use of a inner cavity for channeling the hot air towards the intake air-vent on the rear wall of the casing may require the use of a more powerful centrifugal fan to pump/circulate the hot air through the rotatable drum. A wide shape of the inner cavity, in fact, causes an increase the air pressure loss of the airflow directed towards the rear mouth of the tubular body. Obviously a more powerful centrifugal fan implies a greater electricity consumption of the household appliance with all problems concerned.

[0010] Aim of the present invention is to improve the air circulation efficiency inside the rear wall of the casing so to use less powerful centrifugal fan for circulating the stream of hot air across the rotatable drum.

[0011] In compliance with the above aims, according to the present invention there is provided a rotary-drum laundry dryer comprising an outer casing having a front wall and a rear wall, a rotatable drum which is structured for housing the laundry to be dried and is fixed in axially rotating manner inside the casing, and a hot-air generator structured to circulate a stream of hot air through the rotatable drum; said rotatable drum comprising a substantially cylindrical, tubular body having its front rim faced to the front wall of the casing and its rear rim faced to the rear wall of the casing;
the rear wall of the casing comprising an inner section and an outer section that form/delimit in between themselves an inner cavity which is fluidly connected to the hot-air generator; a central portion of the inner section of the rear wall being furthermore permeable to air, so as to put the inside of tubular body in communication with the inner cavity;
the rotary-drum laundry dryer being characterized in that the rear wall of the casing furthermore comprises an air-deflector member which is fitted/ housed into the inner cavity of the rear wall and is shaped/structured so as to channel the stream of hot air that enters into the inner cavity towards the permeable-to-air central portion of the inner section of the rear wall or vice versa.

[0012] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that the inner cavity is fluidly connected to the hot-air generator through an air-passage opening located close to the peripheral border of the same inner cavity.

[0013] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that the air-deflector member comprises a peripheral element which is fitted into the inner cavity, and is suitably shaped/dimensioned so as to form, inside the inner cavity, a partitioning wall that almost completely encircles the permeable-to-air central portion of the inner section and prevents the airflow from reaching the peripheral border of the inner cavity.

[0014] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that the peripheral element is substantially ring-shaped and the inner cavity is substantially circular in shape, and is arranged inside the rear wall substantially coaxial to the rear rim of the tubular body.

[0015] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that the air-deflector member comprises an opened coupling section which is substantially aligned to an air-passage opening located close to the peripheral border of said inner cavity, so as to allow the free entrance of the stream of hot air generated by hot-air generator inside the air-deflector element.

[0016] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that the opened coupling section of the air-deflector member comprises a protruding plug-assembly which is shaped/structured to fit into the air-passage opening located close to the peripheral border of said inner cavity.

[0017] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that the air-deflector member is realized in plastic material.

[0018] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that the rear wall of the casing comprises a substantially vertically-oriented supporting bulkhead and a lid or cover which is fixed to the inner or outer face of the supporting bulkhead aligned to the rear mouth of the tubular body delimited by said rear rim, so as to form, together with said supporting bulkhead, said inner cavity fluidly connected to the hot-air generator.

[0019] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that the lid or cover is fixed in substantially airtight manner to the inner face of the supporting bulkhead.

[0020] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that the supporting bulkhead is furthermore provided with a substantially sink-shaped bulge which is aligned/faced to a rear mouth of the tubular body delimited by said rear rim, projects inwards or outwards of the casing and communicates with the hot-air generator; the lid or cover being fixed to the supporting bulkhead so as to completely cover said outwards-projecting or inwards-projecting bulge.

[0021] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that the front rim of the tubular body is coupled in substantially airtight and axially rotating manner to the rear wall of the casing with the interposition of a rear circular sealing gasket.

[0022] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that the rear wall of the casing furthermore comprises a substantially cylindrical gasket-supporting collar which has a nominal diameter greater than that of the rear rim of the tubular body, and protrudes from the inner face of the rear wall towards the tubular body while remaining substantially coaxial to the rear rim of the tubular body; a rear circular sealing gasket being fitted into said gasket-supporting collar.

[0023] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that the lid or cover or a substantially sink-shaped bulge provided on the supporting bulkhead is suitably shaped so as to form, on the rear wall of casing and together with the gasket-supporting collar, a substantially circular-shaped annular groove or seat which is arranged coaxial to the rear mouth of tubular body and is suitably shaped/dimensioned so as to completely house the circular sealing gasket.

[0024] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that the hot-air generator comprises: an air recirculating conduit having a first end fluidly connected to the inner cavity of the rear wall, and a second end fluidly connected to the front mouth of the tubular body delimited by said front rim; and an air pumping device located along the air recirculating conduit and structured to produce an airflow which flows through the air recirculating conduit and the rotatable drum; an air cooling device which is located along the air recirculating conduit and is structured to remove moisture from the moist air arriving the from rotatable drum; and an air heating device which is located along the air recirculating conduit, downstream of the air cooling device, and is structured for heating the dehumidified airflow arriving from the air cooling device and directed back to rotatable drum.

[0025] Preferably, though not necessarily, the rotary-drum laundry dryer is furthermore characterized in that said hot-air generator furthermore comprises a heat-pump assembly which comprises a first and a second air/refrigerant heat exchanger both located inside the air recirculating conduit; the first air/refrigerant heat exchanger being structured to remove moisture from the airflow arriving from the rotatable drum, thus forming the air cooling device of the hot-air generator; the second air/refrigerant heat exchanger being located inside the air recirculating conduit downstream of the first air/refrigerant heat exchanger, and being structured to release heat to the airflow arriving from the first air/refrigerant heat exchanger, thus forming the air heating device of the hot-air generator.

[0026] A non-limiting embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

• Figure 1 is a perspective view, with parts removed for clarity, of a rotary-drum laundry dryer realized in accordance with the teachings of the present invention;
• Figure 2 is a section view of the Figure 1e laundry dryer with parts removed for clarity;
• Figure 3 is an enlarged partly-exploded perspective view of the rear wall of the Figures 1 and 2 laundry dryer with parts removed for clarity.

[0027] With reference to Figures 1 and 2, reference number 1 indicates as a whole a rotary-drum laundry dryer which comprises: a preferably, though not necessarily, parallelepiped-shaped, outer boxlike casing 2 which is structured for resting on the floor and is provided with reciprocally-faced, substantially vertically-oriented, front and rear walls 2a and 2b; a substantially cylindrical rotatable drum 3 structured for housing the laundry to be dried, and which is fixed in axially rotating manner inside the boxlike casing 2, facing a laundry loading/unloading pass-through opening formed on the front wall 2a of casing 2; and a porthole door 4 hinged to the front wall 2a of casing 2 so to be able to rotate about a preferably, though not necessarily, vertically-oriented reference axis, to and from a closing position in which the porthole door 4 rests completely against the front wall 2a to close the laundry loading/unloading opening and substantially airtight seal the rotatable drum 3.

[0028] Inside the boxlike casing 2, the laundry dryer 1 additionally comprises an electrically-powered motor assembly (not shown) structured for driving into rotation the rotatable drum 3 about its longitudinal reference axis; an open-circuit or closed-circuit, hot-air generator 6 which is structured to circulate through the rotatable drum 3 a stream of hot air having a low moisture level, and which flows over and rapidly dries the laundry located inside the drum 3; and an electronic central control unit (not shown) which controls both the motor assembly and the hot-air generator 6 to perform, on command, one of the user-selectable drying cycles preferably, though not necessarily, stored in the same central control unit.

[0029] With reference to Figures 1 and 2, the rotatable drum 3 in particular consists in a substantially cylindrical, tubular body 3 which is preferably made of metal material and is arranged inside the boxlike casing 2 coaxial to a preferably substantially horizontally-oriented, longitudinal reference axis L, so that the circular front rim 3f of the tubular body 3 is faced/aligned to the laundry loading/unloading opening realized on the front wall 2a of the boxlike casing 2. The circular rear rim 3r of tubular body 3 abuts against the rear wall 2b of boxlike casing 2. The substantially cylindrical-shaped, tubular body 3 is furthermore preferably structured for resting on a number of idle supporting rollers 8 which are arranged approximately at the two axial ends of the tubular body 3 with their rotation axis substantially parallel to the longitudinal reference axis L of tubular body 3, and are preferably fixed to the boxlike casing 2 in a rotatable manner so as to allow the tubular body 3 to rotate about its longitudinal reference axis L inside the boxlike casing 2.

[0030] Furthermore, the circular front rim 3f of tubular body 3 surrounds the laundry loading/unloading opening realized on the front wall 2a of boxlike casing 2 and is coupled in substantially airtight and axially rotating manner to the front wall 2a, preferably with the interposition of a first circular sealing gasket 9. The circular rear rim 3r of tubular body 3 instead abuts against the rear wall 2b of boxlike casing 2 and is coupled in substantially airtight and axially rotating manner to said rear wall 2b preferably with the interposition of a second circular sealing gasket 10.

[0031] Front and rear circular sealing gaskets 9 and 10 are therefore substantially coaxial to the longitudinal reference axis L of tubular body 3, so that front and rear rims 3f and 3r of tubular body 3 abut against, respectively, front circular sealing gasket 9 and rear circular sealing gasket 10.

[0032] Furthermore front and rear circular sealing gaskets 9 and 10 are preferably, though not necessarily, firmly fixed to, respectively, the front wall 2a and the rear wall 2b of casing 2 so as to remain stationary when rotatable rum 3 rotates about its longitudinal reference axis L.

[0033] In the example shown, the front circular sealing gasket 9 is preferably, though not necessarily, stationary recessed into a circular groove or seat which is realized on a front panel or bulkhead 11 which is preferably associated to the front wall 2a of casing 2 so as to completely surround/delimit the laundry loading/unloading opening on front wall 2a, and the front rim 3f of tubular body 3 abuts against said front circular sealing gasket 9.

[0034] Furthermore, in the example shown the front bulkhead 11 preferably comprises a substantially funnel-shaped coupling element which surrounds the laundry loading/unloading opening on front wall 2a and is shaped/structured so as to connect the laundry loading/unloading opening on front wall 2a to the front rim 3f of tubular body 3, and the front circular sealing gasket 9 is preferably stationary recessed into a circular groove or seat realized on the periphery of the preferably funnel-shaped coupling element of front bulkhead 11.

[0035] With reference to Figure 2, the stream of hot air produced by hot-air generator 6 preferably enters into the tubular body 3 through the rear mouth of tubular body 3 delimited by the rear rim 3r, flows inside tubular body 3 for the entire length of the latter, and comes out of tubular body 3 through the front mouth of tubular body 3 delimited by the front rim 3f, or vice versa.

[0036] In other words, the stream of hot air produced by hot-air generator 6 preferably enters into tubular body 3 through an intake air-vent located in the rear wall 2b of casing 2, within the perimeter of the rear rim 3r of tubular body 3, and comes out of tubular body 3 through an escape air-vent preferably located either on the porthole door 4 that selectively closes the laundry loading/unloading opening of front wall 2a or on the front wall 2a.

[0037] In the example shown, the stream of hot air produced by hot-air generator 6 preferably comes out of tubular body 3 through an escape air-vent incorporated in the substantially funnel-shaped coupling element of front bulkhead 11 that delimits/surrounds the laundry loading/unloading opening on front wall 2a.

[0038] With reference to Figures 2 and 3, the rear wall 2b of boxlike casing 2 instead comprises an inner section 13 and an outer section 14 forming/delimiting in between themselves an inner cavity 15 which is preferably substantially circular in shape and is arranged inside the wall body so as to be faced/aligned to the rear mouth of tubular body 3.

[0039] This inner cavity 15 is furthermore suitably shaped/structured so to communicate with, i.e. be fluidly connected to, the hot-air generator 6 for receiving the stream of hot air produced by hot-air generator 6; and a central portion 13c of the inner section 13 of rear wall 2b is furthermore perforated, or at any rate structured so to be permeable to air, so to put the inside of tubular body 3 in direct communication with the inner cavity 15. Thus the stream of hot air produced by hot-air generator 6 is obliged to flow through the inner cavity 15 for reaching the permeable-to-air central portion 13c of the inner section 13 and from there flooding into the tubular body 3. The permeable-to-air central portion 13c of inner section 13 therefore forms the intake air-vent on the rear wall 2b of casing 2.

[0040] Furthermore, the inner cavity 15 of rear wall 2b is preferably shaped/structured so to communicate with, i.e. be fluidly connected to, the hot-air generator 6 through an air-passage opening located at or close to the peripheral border of the same inner cavity 15.

[0041] In the example shown, the inner cavity 15 is preferably substantially circular in shape and is preferably arranged substantially coaxial to the rear rim 3r of tubular body 3, i.e. substantially coaxial to the drum longitudinal reference axis L.

[0042] The rear circular sealing gasket 10, in turn, is preferably stationary recessed into a circular groove or seat which is realized on the inner face of rear wall 2b so as to completely encircle/surround the permeable-to-air central portion 13c of the inner section 13 of rear wall 2b, i.e. the intake air-vent on the rear wall 2b of casing 2.

[0043] With reference to Figures 1, 2 and 3, in the example shown, the rear wall 2b of boxlike casing 2 preferably comprises a substantially vertically-oriented supporting panel or bulkhead 14 which is preferably made of metal material and is preferably centrally provided with a substantially circular, sink-shaped bulge 14a which is aligned/faced to the rear mouth of tubular body 3 delimited by rear rim 3r, projects/protrudes outwards of boxlike casing 2 and communicates with, i.e. is fluidly connected to, the hot-air generator 6 preferably via a pass-through opening 14b which is realized on the bottom of the sink-shaped bulge 14a, so as to receive the stream of hot air produced by hot-air generator 6.

[0044] Preferably, though not necessarily, the sink-shaped bulge 14a is furthermore substantially coaxial to the longitudinal reference axis L of tubular body 3, i.e. substantially coaxial to the rear rim 3r of tubular body 3, and preferably also has an outer diameter slightly lower than that of the rear rim 3r of tubular body 3, so to be arranged within the perimeter of the rear rim 3r of tubular body 3, approximately at centre of rear rim 3r.

[0045] Lastly, the sink-shaped bulge 14a is preferably deep-drawn on supporting bulkhead 13.

[0046] In addition to the above, the rear wall 2b of boxlike casing 2 furthermore comprises a lid or cover 13 which has a perforated, or at any rate permeable to air, central portion 13c, is suitably shaped/dimensioned so as to be able to completely cover the outwards-projecting, sink-shaped bulge 14a of supporting bulkhead 14, and is firmly fixed preferably in substantially airtight manner to the inner face of supporting bulkhead 14 at closure of the sink-shaped bulge 14a (i.e. aligned/faced to the rear mouth of tubular body 3), so as to form/delimit, together with the supporting bulkhead 14, a preferably substantially circular, inner cavity 15 which is faced/aligned to the rear mouth of tubular body 3 and which communicates with, i.e. is fluidly connected to, the hot-air generator 6 so as to receive the stream of hot air produced by the hot-air generator 6.

[0047] In the example shown, the lid or cover 13 is preferably substantially circular in shape, has an outer diameter greater than that of sink-shaped bulge 14a and preferably also of rear rim 3r of tubular body 3, and is firmly fixed in substantially airtight manner to the inner face of supporting bulkhead 14 substantially coaxial to the rear rim 3r of tubular body 3, i.e. coaxial to the drum longitudinal reference axis L, so as to form/delimit, together with the supporting bulkhead 14, a substantially circularinner cavity 15 which is arranged inside the rear wall 2b of boxlike casing 2 substantially coaxial to the longitudinal reference axis L of tubular body 3, i.e. substantially coaxial to the rear rim 3r of tubular body 3.

[0048] Furthermore, in the example shown the lid or cover 13 is preferably firmly fixed to the inner face of supporting bulkhead 14 in substantially airtight manner with the interposition of an annular sealing gasket 16 completely surrounding the perimeter of the outwards-projecting sink-shaped bulge 14a of supporting bulkhead 14.

[0049] Furthermore, in the example shown the permeable-to-air central portion 13c of the lid or cover 13 is preferably substantially circular in shape and is preferably located substantially coaxial to drum longitudinal reference axis L, i.e. coaxial to the rear rim 3r of tubular body 3.

[0050] Lastly the lid or cover 13 is preferably realized in plastic material, preferably via an injection molding process.

[0051] With reference to Figures 2 and 3, the rear wall 2b of boxlike casing 2 furthermore comprises a circular gasket-supporting collar 17 which has a nominal diameter greater than that of the rear rim 3r of tubular body 3, and is firmly fixed to the inner face of the supporting bulkhead 14 and/or to the peripheral border of the inner face of the lid or cover 13, i.e. to the inner face of the inner section 13 of rear wall 2b, so to protrude from the inner face of the inner section 13 of rear wall 2b towards the tubular body 3 while remaining substantially coaxial to the rear rim 3r of tubular body 3, and preferably also up to completely encircle/surround said rear rim 3r.

[0052] In the example shown, the circular gasket-supporting collar 17 and the lid or cover 13 are preferably rigidly fixed to one another and to the supporting bulkhead 14 preferably, though not necessarily, via seam-folding and/or clinching.

[0053] As an alternative the circular gasket-supporting collar 17 may be realized in one piece with the lid or cover 13. Furthermore, the peripheral border of the substantially circular-shaped lid or cover 13 may be L-bent upwards so as to form the cylindrical gasket-supporting collar 17.

[0054] With reference to Figure 2, the rear circular sealing gasket 10 is fitted/recessed into the gasket-supporting collar 17 preferably in substantially airtight manner, and is suitably shaped/dimensioned so as to come in abutment against the rear rim 3r of tubular body 3 without interruption all around the perimeter of the latter, so as to avoid any air leakage between the rear rim 3r of tubular body 3 and the supporting bulkhead 14 or the lid or cover 13 according to the arrangement of the two component parts.

[0055] In the example shown, the rear circular sealing gasket 10 is preferably suitably shaped/dimensioned so as to abuts against the peripheral border of the lid or cover 13 without interruption all around the perimeter of the gasket, so as to avoid any air leakage between the circular sealing gasket 10 and the lid or cover 13. Furthermore, the circular sealing gasket 10 is preferably also fixed to the peripheral border of the lid or cover 13 and/or rigidly fixed, and/or force-fitted into and/or glued to the gasket-supporting collar 17.

[0056] With reference to Figure 2, in the example shown the lid or cover 13 is furthermore preferably suitably shaped so as to form, on the inner face of rear wall 2b of casing 2 and together with the gasket-supporting collar 17, a substantially circular-shaped annular groove or seat 10a which is arranged coaxial to the rear mouth of tubular body 3 and is suitably shaped/dimensioned so as to completely house the circular sealing gasket 10.

[0057] Furthermore, in the example shown, the lid or cover 13 is preferably substantially dish- or basin-shaped and is firmly fixed to the inner face of the supporting panel or bulkhead 14 coaxial to the rear rim 3r of tubular body and with its concavity faced to the sink-shaped bulge 14a of supporting bulkhead 14, so as to form, on the rear wall 2b of casing 2 and together with the gasket-supporting collar 17, a substantially circular-shaped annular groove or seat 10a which is arranged coaxial to the rear mouth of tubular body 3 and is suitably shaped/dimensioned to house the circular sealing gasket 10.

[0058] Furthermore a circular-shaped central section of the substantially dish- or basin-shaped lid or cover 13 is preferably counter-bulged towards the bottom of the outwards-projecting sink-shaped bulge 14a of supporting bulkhead 14 so as to form, inside the rear wall 2b of the boxlike casing 2, a substantially circular inner cavity 15. The perforated central portion 13c of the lid or cover 13 is preferably located on the counter-bulged circular-shaped central section of the substantially dish- or basin-shaped lid or cover 13, so as to approximately at centre of the rear mouth of tubular body 3.

[0059] With reference to Figures 2 and 3, the rear wall 2b of boxlike casing 2 preferably, though not necessarily, also comprises a laundry anti-entangling nose 19 which protrudes from the inner face of the lid or cover 13 and extends inside the tubular body 3 preferably while remaining substantially coaxial to the longitudinal reference axis L of tubular body 3, and is properly shaped/dimensioned so as to prevent, when tubular body 3 rotates, the entangling of the damp laundry located into the rotatable drum 3. The anti-entangling nose 19 is preferably substantially frustoconical in shape.

[0060] In the example shown, the anti-entangling nose 19 preferably comprises: a supporting socket 20 which is structured for being rigidly fixed in abutment on the inner face of the lid or cover 16, preferably substantially at centre of the permeable-to-air central portion of 13c of the same lid or cover 13, preferably, though not necessarily, via a number of fixing members such as anchoring screws, rivets and the like (non shown); and a preferably, though not necessarily, substantially cone shaped, oblong member 21 which is rigidly fixed onto the supporting socket 20, sticks out from the supporting socket 20 inside tubular body 3, and is properly dimensioned/ shaped so as to prevent the damp laundry located into the rotatable drum 3 from entangling, when tubular body 3 rotates, on the inner face of the rear wall 2b.

[0061] As an alternative, the anti-entangling nose 19 could be realized in one piece with the lid or cover 13 and preferably, though not necessarily, may consists in a preferably substantially ogival-shaped bulge which is realized approximately at centre of the lid or cover 13, i.e. in the middle of the perforated central portion 13c of lid or cover 13, and protrudes inside tubular body 3 preferably while remaining substantially coaxial to the longitudinal reference axis L of tubular body 3.

[0062] With reference to Figures 2 and 3, the rear wall 2b of boxlike casing 2 is provided with an internal air-deflector member 22 which is housed/fitted into the inner cavity 15 and is suitably shaped/structured so as to channel the stream of hot air that enters into the inner cavity 15 through the pass-through opening 14b formed on the bottom of the outwards-projecting sink-shaped bulge 14a straight towards the perforated central portion 13c of the lid or cover 13, i.e. towards the permeable-to-air central portion 13c of the inner section 13 of rear wall 2b, or vice versa, while at same time keeping said airflow far away from the peripheral border of the inner cavity 15.

[0063] In other words, the air-deflector member 22 forms, inside the inner cavity 15, a narrow air duct which connects the perforated central portion 13c of the lid or cover 13, i.e. the permeable-to-air central portion 13c of the inner section 13 of rear wall 2b, to the pass-through opening 14b formed on the bottom of the outwards-projecting sink-shaped bulge 14a, i.e. to the air-passage opening fluidly connected to the hot-air generator 6.

[0064] In the example shown, the air-deflector member 22 preferably comprises a substantially circular, ring-shaped peripheral element 22b which is fitted/recessed into the outwards-projecting sink-shaped bulge 14a of supporting bulkhead 14, i.e. into the inner cavity 15, and is suitably shaped/dimensioned so to form, inside the inner cavity 15, an intermediate partitioning wall that almost completely encircles the perforated central portion 13c of the lid or cover 13 and prevents the airflow from reaching the peripheral border of inner cavity 15.

[0065] Furtehrmore, the air-deflector member 22 preferably comprises a substantially circular, ring-shaped peripheral element 22b which is fitted/recessed into the outwards-projecting sink-shaped bulge 14a of supporting bulkhead 14, i.e. into the inner cavity 15, and is shaped/dimensioned so to almost completely surround the perforated central portion 13c of the lid or cover 13, i.e. the permeable-to-air central portion 13c of the inner section 13 of rear wall 2b, and is structured so to rest/abut, substantially all around the perimeter of the ring-shaped element 22, at same time against the bottom of the sink-shaped bulge 14a of supporting bulkhead 14a, i.e. the outer section 14 of rear wall 2b, and against the lid or cover 13, i.e. the inner section 13 of rear wall 2b, so as to confine the stream of hot air beneath the perforated central portion 13c of the lid or cover 13.

[0066] The air-deflector member 22 is provided with an opened coupling section 22a which is substantially aligned to the pass-through opening 14b on the bottom of the outwards-projecting sink-shaped bulge 14a, i.e. to the air entrance point located close to the peripheral border of inner cavity 15, so as to allow the free entrance of the stream of hot air generated by hot-air generator 6 inside the perimeter of ring-shaped element 22.

[0067] In the example shown, the ring-shaped peripheral element 22b preferably has an inner diameter substantially equal to the peripheral diameter of the perforated central portion 13c of lid or cover 13. Instead the opened coupling section 22a is preferably provided with a protruding coupling plug-assembly which is suitably shaped/structured to fit into the pass-through opening 14b formed on the bottom of the outwards-projecting sink-shaped bulge 14a of supporting bulkhead 14a.

[0068] Lastly the air-deflector member 22 is preferably realized in plastic material, preferably via an injection molding process.

[0069] With reference to Figures 1, 2 and 3, the hot-air generator 6, in turn, preferably, though not necessarily, consists in a closed-circuit, hot-air generator 6 which is structured for gradually drawing air from rotatable drum 3; cooling down the air arriving from rotatable drum 3 so to extract and retain the surplus moisture in the air drawn from rotatable drum 3; heating the dehumidified air to a predetermined temperature normally higher than the temperature of the air drawn out from rotatable drum 3; and supplying the heated, dehumidified air back into the rotatable drum 3, where it flows over, the laundry inside the drum to rapidly dry said laundry.

[0070] In other words, the hot-air generator 6 provides for continually dehumidifying and heating the air circulating inside rotatable drum 3 to dry the laundry located inside the drum 3, and preferably comprises:

• an air recirculating conduit 24 having a first end in direct communication with, i.e. fluidly connected to, the inner cavity 15 formed inside the rear wall 2b of casing 2, and a second end in direct communication with, i.e. is fluidly connected to, the front mouth of tubular body 3;
• an electrically-powered centrifugal fan 25 or other type of air circulating pump, which is located along the air recirculating conduit 24 and is structured to produce an airflow f which flows in closed loop through the air recirculating conduit 24 and the rotatable drum 3;
• an air cooling device 26 which is located along the air recirculating conduit 24 preferably, thought not necessarily, upstream of the air centrifugal fan 25, and is structured to cool the moist air arriving from rotatable drum 3 so as to cause the condensation of the surplus moisture inside the airflow f; and
• an air heating device 27 which is located along the air recirculating conduit 24, downstream of the air cooling device 26 and preferably also upstream of the air centrifugal fan 25, and which is structured for heating the dehumidified airflow f arriving from the air cooling device 26 and directed back to rotatable drum 3, so that the airflow f directed back into rotatable drum 3 is heated to a temperature preferably, though not necessarily, higher than or equal to that of the moist air flowing out of rotatable drum 3.

[0071] Furthermore, the first end of the air recirculating conduit 24 communicates with, i.e. is fluidly connected to, the sink-shaped bulge 14a of the supporting panel or bulkhead 14, i.e. with/to the inner cavity 15 of the rear wall 2b, via the pass-through opening 14b. The second end of the air recirculating conduit 24, instead, communicates with, i.e. is fluidly connected to, the front mouth of tubular body 3 via a pass-through opening realized in the preferably funnel-shaped coupling element of front bulkhead 11 that delimits/surrounds the laundry loading/unloading opening on the front wall 2a of the boxlike casing 2.

[0072] As regards air cooling device 26 and air heating device 27, in the example shown, the hot-air generator 6 is preferably, though not necessarily, provided with a heat-pump assembly which is structured for continuously removing moisture from and then heating the air circulating inside the air recirculating conduit 24 and the rotatable drum 3. This heat-pump assembly comprises a first and a second air/refrigerant heat exchangers both located inside the air recirculating conduit 24, preferably upstream of the centrifugal fan 25. The first air/refrigerant heat exchanger, traditionally referred to as the "evaporator" of the heat-pump circuit, is located inside the air recirculating conduit 24 preferably upstream of the centrifugal fan 25, and is structured to remove/ absorb heat from the airflow arriving from rotatable drum 3, thus forming the air cooling device 26 of the hot-air generator 6. The second air/refrigerant heat exchanger, traditionally referred to as the "condenser" of the heat-pump circuit, is instead located inside the air recirculating conduit 24 downstream of the first air/refrigerant heat exchanger 26, and is structured to release heat to the airflow arriving from the first air/refrigerant heat exchanger 26, thus forming the air heating device 27 of the hot-air generator 6.

[0073] As an alternative, the air cooling device 26 of hot-air generator 6 may comprise an air/air heat exchanger which is located inside the air recirculating conduit 24, preferably upstream of the centrifugal fan 25; and which is structured for using the external air to remove moisture from the airflow arriving from rotatable drum 3; whereas the air heating device 27 of hot-air generator 6 may consists in a resistor which is located inside the air recirculating conduit 24, downstream of the air/air heat exchanger and preferably also downstream of the centrifugal fan 25.

[0074] With reference to Figures 1, 2 and 3, moreover in the example shown the outer boxlike casing 2 preferably, though not necessarily, comprises a substantially parallelepiped-shaped supporting basement or socle 30 which is structured for resting on the floor and preferably also for housing at least part of the hot-air generator 6; and a substantially parallelepiped-shaped boxlike cabinet 31 which is rigidly fixed to the top of the supporting basement or socle 30 and is structured so as to house the rotatable drum 3.

[0075] In other words, the laundry loading/unloading opening of the boxlike casing 2 is realized in the front wall of the boxlike cabinet 31, and the porthole door 4 is hinged to the front wall of the same boxlike cabinet 31. The idle supporting rollers 8 that support in rotatable manner the tubular body 3 are instead preferably fixed to the top of the supporting basement or socle 30.

[0076] As regards rotatable drum 3, the circular front rim 3f of tubular body 3 surrounds the laundry loading/unloading opening realized on the front wall of the boxlike cabinet 31 and is coupled in substantially airtight and axially rotating manner to the same front wall of the boxlike cabinet 31, preferably with the interposition of the front circular sealing gasket 9. The circular rear rim 3r of tubular body 3 instead abuts against the rear wall of the boxlike cabinet 12 and is coupled in substantially airtight and axially rotating manner to the same rear wall of the boxlike cabinet 31 preferably with the interposition of the rear circular sealing gasket 10.

[0077] The front circular sealing gasket 9 is therefore preferably stationary recessed into a circular groove or seat realized on a front bulkhead 11 which is preferably incorporated into the front wall of boxlike cabinet 31, and which is preferably provided with a funnel-shaped coupling element that surrounds the laundry loading/ unloading opening on the same front wall, and is shaped/structured so as to connect said laundry loading/unloading opening to the front rim 3f of tubular body 3. The circular sealing gasket 10 is instead preferably stationary recessed into a circular groove or seat realized on the rear wall of the boxlike cabinet 31, and the intake air-vent of hot-air generator 6 is incorporated into the same rear wall of the boxlike cabinet 31.

[0078] As regards the hot-air generator 6, a central/intermediate section of the air recirculating conduit 24 preferably extends in pass-through manner across the supporting basement or socle 30, and the air cooling device 26 and air heating device 27 are preferably completely recessed/housed inside said central/intermediate section of the air recirculating conduit 24.

[0079] With reference to Figures 1 and 2, the centrifugal fan 25 of hot-air generator 6, instead, is preferably located on the back of the supporting basement or socle 30, i.e. on the rear wall 2b of the boxlike casing 2, and is preferably arranged beneath the rear mouth of tubular body 3. Centrifugal fan 25 is furthermore structured so to communicate with, i.e. be fluidly connected to, the pass-through opening 14b formed on the bottom of the outwards-projecting sink-shaped bulge 14a of supporting bulkhead 14, i.e. to the inner cavity 15, and to the central/intermediate section of the air recirculating conduit 24, so as to produce an airflow f that flows from the central/intermediate section of the air recirculating conduit 24 to the inner cavity 15, or vice versa.

[0080] In the example shown, the centrifugal fan 25 of the hot-air generator 6 is preferably at least partly housed/recessed into the supporting basement or socle 30 of casing 2, i.e. into the rear wall 2b of the boxlike casing 2, roughly at the end-opening of the central/intermediate section of the air recirculating conduit 24, and the outer volute or impeller housing of the pump is shaped/structured so as to communicate with, i.e. be fluidly connected to, both the central/ intermediate section of the air recirculating conduit 24 and with the pass-through opening 14b realized on the bottom of the outwards-projecting, sink-shaped bulge 14a of supporting bulkhead 14.

[0081] General operation of the rotary-drum home laundry drier 1 is clearly inferable from the above description, with no further explanation required.

[0082] As regards the air-deflector member 22 arranged inside the inner cavity 15 of rear wall 2a, several experimental tests has revealed that the considerable pressure loss appearing while the stream of hot air flows inside the inner cavity 15 is mainly due to small air turbulences that take place inside the inner cavity 15, close to the peripheral border of the cavity. The air-deflector member 22 keeps the airflow far away from the peripheral border of the inner cavity 15, thus it is capable of greatly reducing the air turbulences that cause the greater than usual pressure loss of the stream of hot air flowing through the inner cavity 15.

[0083] The advantages connected to the structure of the rear wall 2b of boxlike casing 2 are plain. Thanks to the air-deflector member 22, the hot-air generator 6 can use a less powerful centrifugal fan 25 for circulating the stream of hot air across the rotatable drum 3, with all advantages concerned.

[0084] Moreover, the particular structures of the rear wall 2b of boxlike casing 2 allows to significantly increase the maximum flow rate of the airflow entering into the rotatable drum 3, thus significantly reducing duration of the drying cycle.

[0085] Last but not least, the particular structures of the rear wall 2b allow to greatly simplify the assembly of the rear wall 2b of the boxlike casing 2, thus significantly reducing the appliance production costs.

[0086] Clearly, changes may be made to the rotary-drum home laundry drier 1 as described herein without, however, departing from the scope of the present invention.

[0087] For example, in a different embodiment, the rear wall 2b of boxlike casing 2, may comprise a substantially flat, vertically-oriented supporting panel or bulkhead which is faced to the rear rim 3r of tubular body 3 and is centrally provided with a substantially circular, preferably sink-shaped bulge which is aligned/faced to the rear mouth of tubular body 3 delimited by rear rim 3r, and which protrudes towards the rear mouth of tubular body; and a lid or cover which is firmly fixed to the outer face of the supporting bulkhead above the inwards-protruding, sink-shaped bulge of the same bulkhead, so as to form an inner cavity 15 which is aligned/faced to the rear mouth of tubular body 3 delimited by rear rim 3r.

[0088] The lid or cover is furthermore suitably shaped/structured so to communicate with, i.e. be fluidly connected to, the hot-air generator 6 for receiving the stream of hot air produced by hot-air generator 6; and a central portion of the bottom of the inwards-protruding, sink-shaped bulge of the supporting panel or bulkhead is properly perforated, or at any rate permeable to air, so that the stream of hot air produced by hot-air generator 6 is obliged to flow through the inner cavity 15 for reaching the permeable-to-air central portion of the inwards-protruding, sink-shaped bulge of the supporting bulkhead and from there flooding into tubular body 3.

[0089] In other words, in this embodiment the inner section 13 of rear wall 2b is formed by the inwards-protruding, substantially sink-shaped bulge of the supporting bulkhead, whereas the outer section 14 of rear wall 2b is formed by the lid or cover attached to the outer face of the supporting bulkhead.

[0090] In this embodiment, obviously, the circular gasket-supporting collar 17 protrudes from the inner face of the supporting bulkhead coaxial with rear rim 3r, opposite to the externally-fixed lid or cover, and is preferably though not necessarily realized in one piece with the inwardly-arranged supporting bulkhead.

[0091] Preferably, though not necessarily, the sink-shaped bulge of the inwardly-arranged supporting bulkhead is furthermore suitably shaped so as to form, on the inner face of rear wall 2b of casing 2 and together with the gasket-supporting collar 17, the substantially circular-shaped annular groove or seat 10a which houses the circular sealing gasket 10.

Claims

1. Rotary-drum laundry dryer (1) comprising an outer casing (2) having a front wall (2a) and a rear wall (2b), a rotatable drum (3) which is structured for housing the laundry to be dried and is fixed in axially rotating manner inside the casing (2), and a hot-air generator (6) structured to circulate a stream of hot air (f) through the rotatable drum (3); said rotatable drum (3) comprising a substantially cylindrical, tubular body (3) having its front rim (3f) faced to the front wall (2a) of the casing (2) and its rear rim (3r) faced to the rear wall (2b) of the casing (2);
the rear wall (2b) of the casing (2) comprising an inner section (13) and an outer section (14) that form/delimit in between themselves an inner cavity (15) which is fluidly connected to the hot-air generator (6); a central portion (13c) of the inner section (13) of the rear wall (2b) being furthermore permeable to air, so as to put the inside of tubular body (3) in communication with the inner cavity (15);
the rotary-drum laundry dryer (1) being characterized in that the rear wall (2b) of the casing (2) furthermore comprises an air-deflector member (22) which is fitted/ housed into the inner cavity (15) of the rear wall (2b) and is shaped/structured so as to channel the stream of hot air (f) that enters into the inner cavity (15) towards the permeable-to-air central portion (13c) of the inner section (13) of the rear wall (2b) or vice versa.

2. Rotary-drum laundry dryer according to Claim 1, characterized in that the inner cavity (15) is fluidly connected to the hot-air generator (6) through an air-passage opening (14b) located close to the peripheral border of the same inner cavity (15).

3. Rotary-drum laundry dryer according to any one of the foregoing claims, characterized in that the air-deflector member (22) comprises a peripheral element (22b) which is fitted into the inner cavity (15), and is suitably shaped/dimensioned so as to form, inside the inner cavity (15), a partitioning wall that almost completely encircles the permeable-to-air central portion (13c) of the inner section (13) and prevents the airflow from reaching the peripheral border of the inner cavity (15).

4. Rotary-drum laundry dryer according to Claim 3, characterized in that the peripheral element (22b) is substantially ring-shaped and the inner cavity (15) is substantially circular in shape, and is arranged inside the rear wall (2b) substantially coaxial to the rear rim (3r) of the tubular body (3).

5. Rotary-drum laundry dryer according to any one of the foregoing claims, characterized in that the air-deflector member (22) comprises an opened coupling section (22a) which is substantially aligned to an air-passage opening (14b) located close to the peripheral border of said inner cavity (15), so as to allow the free entrance of the stream of hot air (f) generated by hot-air generator (6) inside the air-deflector element (22).

6. Rotary-drum laundry dryer according to Claim 5, characterized in that the opened coupling section (22a) of the air-deflector member (22) comprises a protruding plug-assembly which is shaped/structured to fit into the air-passage opening (14b) located close to the peripheral border of said inner cavity (15).

7. Rotary-drum laundry dryer according to any one of the foregoing claims, characterized in that the air-deflector member (22) is realized in plastic material.

8. Rotary-drum laundry dryer according to any one of the foregoing claims, characterized in that the rear wall (2b) of the casing (2) comprises a substantially vertically-oriented supporting bulkhead (14) and a lid or cover (13) which is fixed to the inner or outer face of the supporting bulkhead (14) aligned to the rear mouth of the tubular body (3) delimited by said rear rim (3r), so as to form, together with said supporting bulkhead (14), said inner cavity (15) fluidly connected to the hot-air generator (6).

9. Rotary-drum laundry dryer according to Claim 8, characterized in that the lid or cover (13) is fixed in substantially airtight manner to the inner face of the supporting bulkhead (14).

10. Rotary-drum laundry dryer according to Claim 8 or 9, characterized in that the supporting bulkhead (14) is furthermore provided with a substantially sink-shaped bulge (14a) which is aligned/faced to a rear mouth of the tubular body (3) delimited by said rear rim (3r), projects inwards or outwards of the casing (2) and communicates with the hot-air generator (6); the lid or cover (13) being fixed to the supporting bulkhead (14) so as to completely cover said outwards-projecting or inwards-projecting bulge (14a).

11. Rotary-drum laundry dryer according to any one of the foregoing claims, characterized in that the front rim (3f) of the tubular body (3) is coupled in substantially airtight and axially rotating manner to the rear wall (2b) of the casing (2) with the interposition of a rear circular sealing gasket (10).

12. Rotary-drum laundry dryer according to any one of the foregoing claims, characterized in that the rear wall (2b) of the casing (2) furthermore comprises a substantially cylindrical gasket-supporting collar (17) which has a nominal diameter greater than that of the rear rim (3r) of the tubular body (3), and protrudes from the inner face of the rear wall (2b) towards the tubular body (3) while remaining substantially coaxial to the rear rim (3r) of the tubular body (3); a rear circular sealing gasket (10) being fitted into said gasket-supporting collar (17).

13. Rotary-drum laundry dryer according to Claim 12, characterized in that the lid or cover (13) or a substantially sink-shaped bulge (14a) provided on the supporting bulkhead (14) is suitably shaped so as to form, on the rear wall (2b) of casing (2) and together with the gasket-supporting collar (17), a substantially circular-shaped annular groove or seat (10a) which is arranged coaxial to the rear mouth of tubular body (3) and is suitably shaped/dimensioned so as to completely house the circular sealing gasket (10).

14. Rotary-drum laundry dryer according to any one of the foregoing claims, characterized in that the hot-air generator (6) comprises: an air recirculating conduit (24) having a first end fluidly connected to the inner cavity (15) of the rear wall (2b), and a second end fluidly connected to the front mouth of the tubular body (3) delimited by said front rim (3f); and an air pumping device (25) located along the air recirculating conduit (24) and structured to produce an airflow (f) which flows through the air recirculating conduit (24) and the rotatable drum (3); an air cooling device (26) which is located along the air recirculating conduit (24) and is structured to remove moisture from the moist air arriving the from rotatable drum (3); and an air heating device (27) which is located along the air recirculating conduit (24), downstream of the air cooling device (26), and is structured for heating the dehumidified airflow (f) arriving from the air cooling device (26) and directed back to rotatable drum (3).

15. Rotary-drum laundry dryer according to Claim 14, characterized in that said hot-air generator (6) furthermore comprises a heat-pump assembly which comprises a first (26) and a second air/refrigerant heat exchanger (27) both located inside the air recirculating conduit (24); the first air/refrigerant heat exchanger (26) being structured to remove moisture from the airflow arriving from the rotatable drum (3), thus forming the air cooling device (26) of the hot-air generator (6); the second air/refrigerant heat exchanger (27) being located inside the air recirculating conduit (24) downstream of the first air/refrigerant heat exchanger (26), and being structured to release heat to the airflow arriving from the first air/refrigerant heat exchanger (26), thus forming the air heating device (27) of the hot-air generator (6).

Drawing