Abstract:
The present invention relates to a laundry treating machine ( 1 ) comprising a casing ( 10 ), a rotatable laundry container ( 7 ) suitable for receiving the laundry to be treated and one or more peripheral units (F 1,  H 1,  T 1,  SW 1,  SW 2,  S 1, 11,  Ml, M 2,  P 1 ) which enable the treatment to be carried out. The laundry treating machine ( 1 ) comprises a control unit ( 20; 120; 220 ) comprising a printed circuit board ( 21; 121; 221 ) with electric and/or electronic devices ( 22 ) mounted thereon. The control unit ( 20; 120; 220 ) comprises a control and communication section ( 31 ) for communicating with a user interface ( 11 ), a motor driving section ( 32; 132 ) for setting and varying the speed of at least a motor and/or a high power loads section ( 28 ) comprising switching devices suitable for controlling at least one heater device (H 1,  R 1,  R 2 ) and a power section ( 24 ) for supplying power to at least one of said sections ( 28, 31, 32; 132 ).

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention concerns the technical field of laundry treating machines, such as laundry washing machines, laundry drying machines or combined washing and drying laundry machines. 
         [0002]    In particular, the present invention refers to laundry drying machines. 
       BACKGROUND ART 
       [0003]    Nowadays the use of laundry treating machines capable of carrying out a washing and/or drying process on laundry is widespread. 
         [0004]    Laundry treating machines generally comprise an external casing provided with a laundry container where the laundry to be treated is placed. 
         [0005]    A loading/unloading door ensures access to the container for the insertion and removal of the laundry. 
         [0006]    Laundry washing machines, for example, comprise an external casing provided with a washing tub which contains a rotatable perforated drum where the laundry to be washed is placed. 
         [0007]    The drum is usually rotated by an electric motor which transmits the rotating motion to the drum, for example by means of a belt/pulley system. 
         [0008]    Laundry washing machines typically comprise a detergent supply unit and a water inlet circuit for the introduction of water and washing/rinsing products (i.e. detergent, softener, etc.) into the tub. 
         [0009]    Known laundry washing machines are also provided with water draining devices that may operate both during the initial phases of the washing cycle and at the end of the same to drain the dirty water. 
         [0010]    Heating means are provided in order to heat the liquid, namely water or water with detergent, inside the tub. Heating means typically comprise electrical heaters, such as a resistor, placed at the bottom of the tub and suited to come into contact with the liquid present on the bottom of the tub. When the heating means are activated the temperature of liquid in which they are immersed increases. 
         [0011]    Analogously laundry drying machines, or dryers, generally comprise an external casing provided with a rotatable drum where the laundry to be dried is placed. 
         [0012]    The drum is usually rotated by an electric motor which transmits the rotating motion to the drum, for example by means of a belt/pulley system. 
         [0013]    Dryers typically comprise an air circuit. Air circulating means and heating means are provided in the air circuit for circulating and heating drying air, respectively. 
         [0014]    In the condenser type dryers, condensing means are further provided in the air circuit for removing moisture from drying air passing through articles to be treated thereby allowing said air to be recirculated cyclically within the air circuit. 
         [0015]    In known condenser type laundry dryers, said means for condensing moisture removed by articles are configured in many different ways. For example the condensing moisture means may comprise an air-air heat exchanger. 
         [0016]    Other type of dryers belonging to the art may comprise a heat pump which both dehumidifies and heats the air. The heat pump typically comprises a closed circuit formed by an evaporator, a condenser, a compressor and expansion means. 
         [0017]    In the cited laundry treating machines the various parts of the machine are opportunely connected with electrical wires which ensure transmission of power and/or data signals. 
         [0018]    The wires connect, therefore, the various peripheral units, such as the drum motor, the heat pump, the electrical heaters, the valves and the sensors (temperature sensors, humidity sensors, pressure sensors, etc.). 
         [0019]    Each peripheral unit is then usually provided with an own control electric or electronic device indispensable for its functioning. 
         [0020]    However, the laundry treating machines above described belonging to the known art pose some drawbacks. 
         [0021]    A first drawback posed by this known technique is constituted by the complexity deriving from the wiring connections between the peripheral units. 
         [0022]    Another drawback posed by this known technique is constituted by the fact that the wiring connections is cumbersome. 
         [0023]    A further drawback posed by this known technique is constituted by the electromagnetic interference caused by the wiring connections between the peripheral units. 
         [0024]    Analogously, another drawback is constituted by the fact that signals between the peripheral units may be corrupted by interference produced by other components, such as motors, electrovalves, relay, etc. 
         [0025]    Interference tends to be more troublesome with the increasing of the numbers of peripheral units. 
         [0026]    The main object of the present invention is therefore to overcome said drawbacks. 
         [0027]    In particular, it is one object of the present invention to provide a laundry treating machine with a system operating the peripheral units which has a reduced constructional complexity with respect to the systems of known type. 
         [0028]    Another object of the present invention is to provide a laundry treating machine wherein assembly has a lower complexity with respect to the laundry treating machines of known type. 
         [0029]    A further object of the present invention is to provide a laundry treating machine with reduced production costs with respect to the laundry treating machines of known type. 
         [0030]    Another object of the present invention is to provide a laundry treating machine with reduced electromagnetic emission with respect to the laundry treating machines of known type. 
         [0031]    A further object of the present invention is to provide a laundry treating machine with increased immunity with respect to external electromagnetic disturbance. 
       DISCLOSURE OF INVENTION 
       [0032]    The applicant has found that by providing a laundry treating machine comprising a laundry container suitable for receiving the laundry to be treated, one or more peripheral units which enable said treatment to be carried out, wherein the machine further comprises a single control unit for controlling of one or more of the peripheral units it is possible to obtain a reduced constructional complexity of the machine itself. 
         [0033]    The present invention relates therefore, in a first aspect thereof, to a laundry treating machine comprising;
       a casing;   a rotatable laundry container suitable for receiving the laundry to be treated;   one or more peripheral units which enable said treatment to be carried out;
 
wherein the machine comprises a control unit comprising a printed circuit board with electric and/or electronic devices mounted thereon, said control unit comprising:
   a control and communication section for communicating with a user interface;   a motor driving section for setting and varying the speed of at least a motor and/or a high power loads section comprising switching devices suitable for controlling at least one heater device; and   a power section for supplying power to at least one of said sections.       
 
         [0040]    Preferably the motor driving section comprises devices suitable for controlling an electric motor. 
         [0041]    Advantageously the devices suitable for controlling an electric motor comprise an inverter. 
         [0042]    Preferably the control unit further comprises a low power loads section for controlling low power loads. 
         [0043]    In a preferred embodiment of the invention, the low power loads comprise a fan or a pump. 
         [0044]    Opportunely, the motor driving section drives an electrical motor for rotating the laundry container. 
         [0045]    In a further preferred embodiment of the invention, the motor driving section drives an electrical motor of a heat pump compressor. 
         [0046]    Preferably the heat pump is suitable to heat air. 
         [0047]    In a preferred embodiment of the invention, the high power loads section suitable for controlling at least one heater device controls a water heater. 
         [0048]    In a further preferred embodiment of the invention, the high power loads section suitable for controlling at least one heater device controls an air heater. 
         [0049]    Advantageously, the high power loads section suitable for controlling at least one heater device controls a second air heater. 
         [0050]    Preferably the high power loads section suitable for controlling at least one heater device controls an electrical heater of a steamer unit for producing steam which is conveyable into the rotatable laundry container. 
         [0051]    Opportunely the low power loads section for controlling low power loads controls a water supply valve and/or a water pump of the steamer unit. 
         [0052]    Preferably the water pump of the steamer unit comprises a water pumping motor. 
         [0053]    In a preferred embodiment of the invention, the control unit further comprises a sensor section for controlling at least a temperature sensor and/or at least a liquid level sensor. 
         [0054]    Advantageously the switching devices comprises electromagnetic or solid-state relays. 
         [0055]    Preferably the control unit further comprises a humidity sensor control section suitable to detect the degree of humidity and/or of the dryness of the laundry in the container in a laundry drying machine or in a combined laundry washing and drying machine. 
         [0056]    In a preferred embodiment of the invention, the control and communication section comprises devices suitable for the communication of power and/or data signals with at least one of the other sections. 
         [0057]    Preferably the control unit comprises a single printed circuit board. 
         [0058]    In a further preferred embodiment of the invention, the printed circuit board comprises one or more empty seats suitable for receiving further devices for controlling one or more further peripheral units. 
         [0059]    Advantageously the power section comprises an input line section connectable to a mains supply and suitable to reduce and/or rectify the voltage of the main supply. 
         [0060]    Preferably the power section further comprises a power supply section connected to the input line section and suitable to set the voltage to predetermined values. Preferably the control unit further comprises a protective cover. 
         [0061]    In a preferred embodiment of the invention, the control unit is a removable unit. 
         [0062]    Opportunely the control unit comprises snap-in fastener means. 
         [0063]    Preferably the snap-in fastener means further comprise electrical connectors. 
         [0064]    Preferably the peripheral units comprise one or more units selected from a group comprising: a motor, an electric motor, a fan, an electric resistance, a pump, a switch, a sensor, a temperature sensor, a level sensor, a humidity sensor, an interface unit, a selector, a display, a valve, an electrovalve. 
         [0065]    In a preferred embodiment of the invention, the machine is a laundry drying machine. 
         [0066]    In another embodiment of the invention, the machine is a combined laundry washing and drying machine. 
         [0067]    In a further embodiment of the invention, the machine is a laundry washing machine. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0068]    Further characteristics and advantages of the present invention will be highlighted in greater detail in the following detailed description of some of its preferred embodiments, provided with reference to the enclosed drawings. In the drawings, corresponding characteristics and/or components are identified by the same reference numbers. In particular: 
           [0069]      FIG. 1  shows an isometric view of a dryer machine with the upper side removed according to a first embodiment of the invention; 
           [0070]      FIG. 2  shows a plan upper view of the dryer machine of  FIG. 1 ; 
           [0071]      FIG. 3  shows a partially exploded view of the dryer machine of  FIG. 1 ; 
           [0072]      FIG. 4  shows a schematic view of a control unit of the dryer machine of  FIG. 1 ; 
           [0073]      FIG. 5  shows a schematic view of connections between the control unit of 
           [0074]      FIG. 4  and other parts of the dryer machine; 
           [0075]      FIG. 6  shows a further embodiment of  FIG. 4 ; 
           [0076]      FIG. 7  shows a schematic view of connections between the control unit of  FIG. 6  and other parts of a dryer machine; 
           [0077]      FIG. 8  shows a further embodiment of  FIG. 4 ; 
           [0078]      FIG. 9  shows a schematic view of connections between the control unit of  FIG. 8  and other parts of a dryer. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0079]    The present invention has proved to be particularly successful when applied to a laundry drying machines, preferably a front load type laundry drying machine. It should in any case be underlined that the present invention is not limited to this type of application. On the contrary, the present invention can be usefully applied to all the laundry treating machines, such as a laundry washing machine or a combined laundry washing and drying machine. 
         [0080]    With reference to  FIG. 1  a laundry drying machine  1  according to a first embodiment of the invention is described. 
         [0081]    The laundry drying machine  1 , hereinafter referred to as dryer  1 , comprises a casing  10  formed by two couples of upright side walls  2   a - 2   d  arranged perpendicularly one another, respectively on the dryer rear and front part, and on the lateral side thereof. An upper wall, not illustrated, and a bottom wall  4  close the ends of the box-like structure formed by the upright side walls  2   a - 2   d  joined together. In  FIG. 1  the upper side wall has been removed for showing some of the dryer parts accommodated within casing  10 . 
         [0082]    A laundry container comprising a rotatably drum  7  is provided within the casing  10 . A front door  8 , pivotally coupled to the front upright side wall  2   a , is provided for allowing access to the drum interior region to place laundry to be dried therein. 
         [0083]    The drum  7  is advantageously rotated by an electric motor M 1 , not shown, which transmits the rotating motion to the drum  7 . In a preferred embodiment, the electric motor M 1  transmits the rotating motion to the drum by means of a belt/pulley system. 
         [0084]    In different embodiments the motor transmits directly the rotating motion to the drum. For example, in a laundry washing machine or in a combined laundry washing and drying machine where the drum is placed inside a washing tub, the electric motor may be arranged so as to have the stator connected to the washing tub and the rotor connected to the drum. 
         [0085]    The dryer  1  is connectable to a mains supply, typically 220 Volts AC, by means of a power cord with a suitable plug, not illustrated 
         [0086]    The dryer  1  comprises an air circulating system adapted to circulate a flow of drying air into the drum  7 . The air circulating system preferably comprises a fan F 1 , not illustrated, which blows a flow of drying air through the drum  7  and the laundry placed therein. 
         [0087]    The fan F 1  preferably comprises an electrical motor connectable to the mains supply, wherein the electrical input power of the motor is preferably less than 50 Watt, more preferably 30 Watt. 
         [0088]    The air circulating system preferably comprises a heating device H 1 , not illustrated, adapted to heat up the air flow at a location upstream of the drum  7 . 
         [0089]    Preferably the heating device H 1  comprises an electric heating element R 1 , such as an electrical resistance, arranged upstream of the drum  7  along the air flow. 
         [0090]    The electric resistance R 1  is preferably connectable to the mains supply and preferably has a dissipated power value about 2 kWatt. 
         [0091]    The dryer  1 , then, advantageously comprises a temperature sensor T 1  for the control of the temperature inside the drum  7  and/or the control of the temperature of the laundry placed therein. 
         [0092]    The dryer  1  is advantageously of the condenser type and comprises condensing means arranged downstream of the drum  7  for cooling and dehumidifying the moist air coming from the drum  7 . 
         [0093]    Preferably, condensing means are in the form of an air-air cross-flow type heat exchanger which is preferably provided on the bottom portion of the dryer  1 . Condensation water formed in the condensing means is advantageously collected in a sump at the bottom of the dryer, not illustrated, and conveyed to an extractable moisture tank  9  located at the upper portion of the dryer  1 . 
         [0094]    The moisture tank  9  is preferably in the form of a drawer slidably arranged on said upper portion of the dryer  1  so that it can be easily and periodically emptied by a user. 
         [0095]    A pump P 1 , not illustrated, opportunely pumps the condensation water from the sump to the tank  9 . 
         [0096]    The pump P 1  preferably comprises an electrical motor connectable to the mains supply. The electrical input power of the motor is preferably less than 100 Watt, more preferably 50 Watt. 
         [0097]    The dryer  1  preferably comprises a humidity sensor S 1  that detects the moisture level of the laundry. The moisture level detected represents a useful parameter which may be used to determine the duration of the drying cycle. 
         [0098]    Furthermore, the dryer  1  preferably comprises a door switch SW 1  which detects the closed position of the door  8 . 
         [0099]    A user control interface  11  is preferably arranged on the top of the casing  10 . The user control interface  11  is preferably accessible to the user for the selection of the drying program and insertion of other parameters, for example the load in terms of weight of the laundry to be dried, the type of fabric of the load, the degree of dryness, etc. The user control interface  11  preferably displays machine working conditions, such as the remaining time, alarm signals, etc. For this purpose the user control interface preferably comprises a rotatable selector  12  and a display  13 . 
         [0100]    In different embodiments, for example in a laundry washing machine or in a combined laundry washing and drying machine, the user may selects and inserts other types of parameters, for example the washing temperature, the spinning speed, etc. 
         [0101]    According to the invention, a control unit  20  is arranged inside the casing  10  at the top portion thereof. 
         [0102]    The control unit  20  is advantageously connected to the various parts of the dryer  1 , or peripheral units, in order to ensure its operation. 
         [0103]    The control unit  20  comprises a printed circuit board  21  that supports the electric and/or electronic devices  22  which assure functioning of the peripheral units and of the dryer  1 , as will be better explained hereinafter. 
         [0104]    The control unit  20  also preferably comprises a cover  23  which protects the electric and/or electronic devices  22 . 
         [0105]    The control unit  20  is advantageously laterally arranged inside the casing  10  close to an upright side wall  2   a , the right one with reference to  FIG. 1 . The control unit  20  is preferably placed inside the casing  10  and above the drum  7  or the washing tub through snap-in fastener means. 
         [0106]    More preferably electrical connectors are associated to said snap-in fastener means allowing therefore both the mechanical and the electrical connection. 
         [0107]      FIG. 4  shows a schematic view of the control unit  20  according to the invention wherein blocks represent different sections  24 - 32  of the control unit  20 . Each section  24 - 32  comprises suitable electric and/or electronic devices  22 . 
         [0108]      FIG. 5  shows the control unit  20  of the dryer  1  connected to various peripheral units M 1 , F 1 , H 1 , T 1 , P 1 , S 1 , SW 1 ,  11 . 
         [0109]    The control unit  20  preferably comprises a power section  24 , indicated with a dashed line in  FIG. 4 , a low power loads section  27 , a high power loads section  28 , a machine sensors section  29 , a humidity sensor control section  30  and a control and communication section  31 . 
         [0110]    The power section  24  preferably comprises an input line section  25  and a power supply section  26 . 
         [0111]    The input line section  25  comprises devices suitable for lowering and/or rectifying the voltage from the mains supply to which the dryer  1  is connected. 
         [0112]    Devices of this section may comprise, for example, transformers rectifiers, filters, etc. 
         [0113]    The power supply section  26  is connected to the input line section  25  and furnishes the proper supply voltage to other sections of the control unit  20 . Devices of this section may comprise, for example, linear regulators. 
         [0114]    In different embodiments the input line section  25  and/or the power supply section  26  may be connected to energy storage devices such as batteries, fuel cells, solar cell, etc. 
         [0115]    The low power loads section  27  preferably comprises devices suitable for controlling low power loads, such as the fan F 1  or the pump P 1 . 
         [0116]    The expression “low power loads” may be generally referred to loads wherein the power dissipation is preferably less than 100 Watt. 
         [0117]    The low power loads and section  27  preferably comprises switching devices suitable for controlling, for example switch on and/or switch off, the motors of the fan F 1  and/or of the pump P 1 . 
         [0118]    In different embodiments, this section  27  may control and drive other components. For example this section  27  may control electrovalves or may control and drive the pumps which are disposed in the water inlet circuit and/or in the water outlet circuit of a laundry washing machine. 
         [0119]    Further, this section  27  may advantageously control a steamer in laundry treating machines where a steamer unit is provided. In fact a steamer unit may be provided in laundry washing machine in order to increases the washing temperature of the laundry and/or to assist cleaning of the laundry. A steamer unit may be provided in a dryer in order to soften and refresh laundry during the drying treatment. The steamer unit can be any type of device that converts the liquid to steam. 
         [0120]    A first type of steamer unit can be a tank-type steam generator that stores a volume of liquid and heats the volume of liquid to convert the liquid to steam. The steamer unit preferably comprises an electrical heater, preferably an electrical resistance, which is immersed in a minimum quantity of water of said tank for the production of steam. 
         [0121]    In a preferred embodiment, the water is preferably conveyed into the tank through a water supply pipe from an external water supply by means of a controlled water supply valve. In this case, the low power loads section  27  preferably controls and drives such water supply valve. 
         [0122]    In a further embodiment the water may be preferably conveyed into the tank by means of a water pumping motor connected to an external water supply. The water pumping motor preferably comprises an electrical motor connectable to the mains supply. The electrical input power of the motor is preferably less than 100 Watt, more preferably 50 Watt. 
         [0123]    In this specific case, the low power loads section  27  preferably controls and drives the water pumping motor. 
         [0124]    A second type of steamer unit can be an in-line steamer unit. The in-line steamer unit converts the liquid to steam as the liquid flows through the steam unit itself. The steamer unit in this case preferably comprises an electrical heater, more preferably an electrical resistance, which heats the water flowing in a duct. The water is conveyed into the duct by means of a water pumping motor which suck water from a tank. The water pumping motor preferably comprises an electrical motor connectable to the mains supply. The electrical input power of the motor is preferably less than 100 Watt, more preferably 50 Watt. 
         [0125]    In this case, the low power loads section  27  preferably controls and drives the water pumping motor. 
         [0126]    In a further embodiment the in-line steamer unit can be connected directly to the water mains via a valve and the low power loads section  27  preferably controls and drives said valve. 
         [0127]    Devices of this section  27  may comprise, for example, electronic components like solid-state relays (TRIAC, ACS, etc.), optical isolators, transistors, capacitors, resistors, etc. 
         [0128]    The high power loads section  28  preferably comprises devices suitable for controlling high power loads, such as the heater H 1 . The heater H 1  preferably comprises an electrical resistance R 1 , as said before. 
         [0129]    The expression “high power loads” may be generally referred to loads wherein the power dissipation is preferably higher than 100 Watt. 
         [0130]    The high power loads section  28  preferably comprises high power switching devices suitable for controlling, for example switch on and/or switch off, the electrical resistance R 1 . 
         [0131]    In different embodiments, the heater H 1  may comprises a second electrical resistance R 2  in order to better control the air temperature of the drying air flow. In this case, the high power loads section  28  preferably controls, i.e. switches on and/or switches off, the second resistance R 2  too. 
         [0132]    The second electric resistance R 2  is preferably connectable to the mains supply and preferably has a dissipated power value about 600 Watt. 
         [0133]    In further embodiments other high power switches may be provided. 
         [0134]    For example in case of a laundry treating machine having a steamer unit, as mentioned above, this section  28  may switch on and/or switch off the electrical resistance of the steamer unit itself. 
         [0135]    The electric resistance of a steamer unit is preferably connectable to the mains supply and preferably has a dissipated power value about 2 kWatt. 
         [0136]    In a further embodiment, for example in a laundry washing machine, the high power loads section may comprise a switch which activates and deactivates the heater which heats the washing water, the heater being typically an electrical resistance. The electric resistance of such water heating unit is preferably connectable to the mains supply and preferably has a dissipated power value about 2 kWatt. 
         [0137]    If the laundry washing machine is also provided with a steamer unit then this section  28  advantageously controls also the electrical resistance of the steamer unit itself. 
         [0138]    Devices of this section  28  may comprise, for example, electromagnetic or solid-state relays, transistors, etc. 
         [0139]    The machine sensors section  29  preferably comprises devices suitable for detecting and elaborating signals coming from sensors of the dryer  1 , such as the temperature sensor T 1  and the door switch SW 1 . 
         [0140]    In different embodiments, this section  29  may detect and elaborate other signals, such as a signal coming from a water level sensor placed inside the sump which collects the moisture, or a signal coming from a water level sensor placed inside the washing tub in a laundry washing machine or a signal coming from a lint filter monitoring sensor in a dryer. 
         [0141]    The sensors section  29  is preferably powered by the power supply section  26 . 
         [0142]    Devices of this section  29  may comprise, for example, transistors, capacitors, resistors, etc. 
         [0143]    The humidity sensor control section  30  preferably comprises devices suitable to detect and elaborate signals coming from the humidity sensor S 1 . Such elaborated signals are preferably used to determine the dryness of the clothes and therefore the duration of the drying program. 
         [0144]    In a preferred embodiment the humidity sensor S 1  may comprise elements which are contacted by the tumbling clothes during a drying operation. Preferably the elements comprise a pair of electrodes which are provided within the dryer and face toward the interior of the dryer drum  7  such that clothes being tumbled and dried will periodically engage and bridge the electrodes. The sensed resistance between the electrodes is used to determine the dryness of the clothes. 
         [0145]    A high resistance between the electrodes is indicative of dry clothes. A low resistance between the electrodes is indicative of wet clothes. Appropriate control circuitry, including time delays, make it possible to determine when the clothes have reached a desired dryness condition. 
         [0146]    In different embodiments any other equivalent sensor device may be used in order to detect the dryness condition of the clothes. 
         [0147]    Devices of the humidity sensor control section  30  may comprise, for example capacitors, resistors, etc. Preferably this section is electrically insulated from the humidity sensor S 1  and advantageously comprises insulator devices like optical isolators or transformers. 
         [0148]    In different embodiments where the electrical insulation is not required for the humidity sensor S 1 , this humidity sensor control section  30  may be part of the above described machine sensors section  29 . 
         [0149]    The control and communication section  31  advantageously communicates with all said sections  24 - 30  and with the user control interface  11 . The control and communication section  31  preferably comprises a main microcontroller. This section  31  gets data from the rotatable selector  12 , outputs data for the display  13  and controls other sections  24 - 30  during the drying cycle. 
         [0150]    In different embodiments data from the rotatable selector  12  and to the display  13  may be elaborated in an intermediate local microcontroller which, in turn, communicates with the main microcontroller. 
         [0151]    The control and communication section  31  is preferably powered by the power supply section  26 . 
         [0152]    According to the invention, the control unit  20  preferably comprises a motor control section  32 . More preferably, the control unit  20  comprises a drum motor control section  32 . 
         [0153]    In different embodiments, the control unit  20  may alternatively comprise a compressor motor control section, preferably a compressor motor of a heat pump unit, as described later in the description. 
         [0154]    The motor control section  32  preferably comprises an inverter motor control so that the speed of the drum electric motor M 1  may be controlled. 
         [0155]    Therefore, the motor control section  32  advantageously sets and controls the speed of the drum  7  during the drying cycle. 
         [0156]    The motor control section  32  is preferably powered by the input line section  25 . 
         [0157]    In particular the inverter motor control is connected to a direct current (DC) source provided by a rectifier section of the input line section  25 . 
         [0158]    Devices of the motor control section  32  may comprise, for example, oscillators, IGBT, MosFet, drivers, logic control units, sensors for temperature protection and current limiting, etc. 
         [0159]    In further embodiments, said devices may be integrated into a single embedded device. 
         [0160]    Advantageously, the control unit  20  of the invention with its sections  24 - 32  incorporates almost all the electric and/or the electronic devices  22  indispensable for the dryer functioning. 
         [0161]    The quantity of wiring connections between the devices  22  and the peripheral units  24 - 32  are therefore widely reduced with respects to the known dryers, and more in general to the known laundry treating machines. 
         [0162]    Reduction of the wiring connections causes also a reduction of electromagnetic emissions and, at the same time, increases immunity with respect external electromagnetic disturbance. 
         [0163]    More, the provision of such a control unit  20  with a preferably single printed circuit board  21  allows positioning of the electric and/or electronic devices  22  with an efficient layout in order to reduce the overall dimensions of the control unit  20  and, eventually, of the machine. 
         [0164]    Furthermore, the provision of such a control unit  20  with almost all the devices of the machine mounted thereon helps detection and repairing of failures when they occur. 
         [0165]    With reference to  FIGS. 6 and 7  a further construction variant of a control unit  120  is described. 
         [0166]    This control unit  120  differs from the control unit  20  previously described for the fact that it comprises a further motor control section  132 . 
         [0167]    The control unit  120  is suitable to be installed in a dryer of the type previously described which further comprises a heat pump unit HP. Dryers provided with a heat pump unit HP are widespread. The heat pump unit HP both dehumidifies and heats the air flow which dries the laundry. The heat pump unit HP preferably comprises a closed circuit formed by a first heat exchanger, for example an evaporator or a gas heater, a second heat exchanger, for example a condenser or a gas cooler, a compressor connecting the two heat exchangers and expansion means. 
         [0168]    The first heat exchanger of the heat pump HP cools and dehumidifies the moist air coming from the drum  7 . The cooled and dehumidified air is then heated up by the second heat exchanger of the heat pump HP and conveyed again inside the drum  7 . 
         [0169]    In the preferred embodiment here described, the dryer is also provided with a heating device H 1  which helps the second heat exchanger to heat up the air. Preferably the heating device H 1  comprises an electric heating resistance R 1  arranged upstream of the drum  7  along the air flow. 
         [0170]    More preferably the heating device H 1  comprises a second electrical resistance R 2  in order to better control the air temperature of the drying air flow. 
         [0171]    Activation and deactivation of the first and/or of the second electric heating resistances R 1 , R 2  is properly controlled by the high power loads section  28 . Preferably both the resistances R 1 , R 2  are activated at the beginning of the laundry drying program while one or both of them are deactivated when the heat pump HP reaches an optimal working condition. 
         [0172]    In different embodiments, only the heat pump HP may be provided to heat up the air temperature while the heating device H 1  may be avoided. 
         [0173]    The compressor of the heat pump HP preferably comprises a variable speed electric motor M 2 . 
         [0174]    The motor control section  132 , therefore, preferably comprises an inverter motor control so that the speed of the heat pump motor M 2  may be easily controlled. 
         [0175]    Devices of this section may comprise, for example, oscillators, IGBT, MosFet, drivers, logic control units, sensors for temperature protection and current limiting, etc. 
         [0176]    In further embodiments, said devices may be integrated into a single embedded device. 
         [0177]    The control and communication section  31  then advantageously communicates with the further motor control section  132 . 
         [0178]    With reference to  FIGS. 8 and 9  a further construction variant of control unit  220  is described. 
         [0179]    The control unit  220  comprises a printed circuit board  221  that supports the electric and/or electronic devices which assure functioning of the machine where it is installed. 
         [0180]    On the printed circuit board  221  a plurality of sections are provided, namely: a power section  24 , a low power loads section  27 , a high power loads section  28 , a machine sensors section  29 , a humidity sensor control section  30 , a control and communication section  31  and a motor control section  32 . 
         [0181]    The printed circuit board  221  further comprises a first empty seat  221   a  predisposed to receive devices of a further motor control section  132 , for example a control section for a heat pump motor. 
         [0182]    The printed circuit board  221  further comprises a second empty seat  221   b  inside the high power loads section  28 , predisposed to receives devices for a steamer control section, for example a steamer switch SW 2  which activates and deactivates the electrical resistance of a steamer unit. 
         [0183]    Advantageously a multipurpose printed circuit board  221  according to this embodiment may be used for the realization of control units  20 ,  120 ,  220  of different types, for example a control unit  120  for a dryer with a heat pump or a control unit  20  for a dryer without a heat pump. 
         [0184]    This multipurpose printed circuit board  221  allows reduction of the overall production costs of laundry treating machines wherein such a multipurpose boards  221  are installed. 
         [0185]    In further embodiments, the laundry treating machines may comprise further temperature sensors. For example a laundry washing machines may preferably comprise a temperature sensor which detects the temperature of the washing water. Other temperature sensors may be used to control overheat of peripheral units. For example a sensor temperature may be placed near the electrical resistance or near the condenser of a heat pump to check its working temperature. 
         [0186]    In the following some examples of laundry treatment machines in which a control unit according to the invention may be installed are provided. 
         [0187]    A laundry drying machine having an air heating device comprising one or two electrical resistances to heat up the air. 
         [0188]    A laundry drying machine having an air heating device comprising one or two electrical resistances to heat up the air and having a steamer unit comprising an electrical resistance and a water supply valve. 
         [0189]    A laundry drying machine having an air heating device comprising one or two electrical resistances to heat up the air and having a steamer unit comprising an electrical resistance and a water supply pumping motor. 
         [0190]    A laundry drying machine using a heat pump to heat up the air. The heat pump may preferably comprise a compressor motor, more preferably a speed controlled electric motor. 
         [0191]    A laundry drying machine using a heat pump and one or two electrical resistances to heat up the air. The heat pump may preferably comprise a compressor motor, more preferably a speed controlled electric motor. 
         [0192]    A laundry drying machine using a heat pump to heat up the air and having a steamer unit comprising an electrical resistance and a water supply valve. The heat pump may preferably comprise a compressor motor, more preferably a speed controlled electric motor. 
         [0193]    A laundry drying machine using a heat pump to heat up the air and having a steamer unit comprising an electrical resistance and a water supply pumping motor. The heat pump may preferably comprise a compressor motor, more preferably a speed controlled electric motor. 
         [0194]    A laundry drying machine using a heat pump and one or two electrical resistances to heat up the air and having a steamer unit comprising an electrical resistance and a water pumping motor. The heat pump may preferably comprise a compressor motor, more preferably a speed controlled electric motor. 
         [0195]    A laundry washing machine having a water heating device comprising an electrical resistance to heat up the water. 
         [0196]    A laundry washing machine having a water heating device comprising an electrical resistance to heat up the water and having a steamer unit comprising an electrical resistance and a water supply valve. 
         [0197]    A laundry washing machine having a water heating device comprising an electrical resistance to heat up the water and having a steamer unit comprising an electrical resistance and a water supply pumping motor. 
         [0198]    A combined laundry washing and drying machine which may comprises one or more features of the above listed laundry drying machine and laundry washing machine. 
         [0199]    It has thus been shown that the present invention allows all the set objects to be achieved. In particular, it makes it possible to obtain a laundry treating machine with a reduced constructional complexity with respect to the laundry treating machines of known type. 
         [0200]    Clearly, changes may be made to the laundry drying machine as described herein without, however, departing from the scope of the present invention. 
         [0201]    Therefore, while the treating drying machine has been described with reference to a laundry drying machine, it should be noted that the present invention is not limited to the specific embodiment illustrated and described herein; on the contrary, further variants of the embodiments described herein fall within the scope of the present invention, which is defined in the claims.