Patent Publication Number: US-2006005581-A1

Title: Laundry machine

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a laundry machine and, more specifically, a laundry machine having a drying function.  
      2. Description of Related Art  
      Drum type laundry machines are known which are adapted to perform a laundry process and a drying process for laundry contained in a generally cylindrical drum rotatable about a generally horizontal axis.  
      One exemplary drum type laundry machine is further adapted to introduce steam into the drum during the drying process to unwrinkle the laundry as disclosed in Japanese Unexamined Patent Publication No. 5-23493 (1993).  
      In the drum type laundry machine disclosed in this publication, a water container is provided below an outer tub which rotatably supports the drum, and a heater is provided in the water container. Water is contained in the water container, andheatedby the heater for generation of thesteam. Thesteamisintroducedintothedrumthrough drum wall holes (water passage holes through which water is drained during a dewatering step) formed in a circumferential wall of the drum.  
      The drum type laundry machine is further adapted to heat water retained up to a predetermined water level in the outer tub by the heater in a soaking step and a washing step.  
      In this drum type laundry machine, however, the efficiency of the introduction of the steam into the drum is not high, because the steam is supplied into the drum through the small water passage holes.  
      In the drum type laundry machine, air streams generated by the rotation of the drum are heated by the heater, and then introduced into the drum through the drum wall holes for drying the laundry in the drum. Therefore, the efficiency of the drying is not high. A conceivable approach to this is to provide another heater in a drying air passage separately from the heater provided in the water container and use this heater in the drying process. However, this approach is costly.  
      The drum type laundry machine is further adapted to heat the water for improvement of a washing capability. In this case, a great amount of water should be heated, requiring a great amount of heat. Therefore, the power consumption is considerably increased.  
     SUMMARY OF THE INVENTION  
      In view of the foregoing, it is an object of the present invention to effectively supply steam to laundry in a drum. It is another object of the present invention to provide an arrangement for supplying steam into a drum (laundry drum) at lower costs. It is further another object of the present invention to efficiently improve a washing capability and a dewatering capability.  
      The present invention provides a laundry machine, which includes a steam supply port provided in one end face of a drum for supplying steam into the drum, and a steam supplying device provided in an air passage communicating with the steam supply port, the steam supplying device including a blower, a heater and means for supplying water to the heater.  
      The steam supplying device is allowed to double as hot air supplying device for drying laundry by controlling operation states of the blower and the water supplying means. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view illustrating the exterior of a drum type laundry machine according to one embodiment of the present invention;  
       FIG. 2  is a front vertical sectional view illustrating the internal construction of the drum type laundry machine of the embodiment;  
       FIG. 3  is a side vertical sectional view illustrating the internal construction of the drum type laundry machine of the embodiment;  
       FIG. 4  is a side view illustrating a major internal construction of the drum type laundry machine of the embodiment;  
       FIG. 5  is a top cross sectional view mainly illustrating a drying air passage in the drum type laundry machine of the embodiment;  
       FIG. 6  is an enlarged rear view illustrating in detail the structure of a dehumidification air passage in the drum type laundry machine of the embodiment;  
       FIG. 7  is a sectional view taken along a line A-A in  FIG. 6 ;  
       FIG. 8  is a front vertical sectional view illustrating the structure of a supply port of a drum in the drum type laundry machine of the embodiment;  
       FIG. 9  is an electric block diagram of the drum type laundry machine;  
       FIG. 10  is a flow chart illustrating operations to be performed in a laundry/drying process in the drum type laundry machine of the embodiment;  
       FIG. 11  is a flow chart illustrating a second washing step to be performed in the laundry/drying process in the drum type laundry machine of the embodiment; and  
       FIG. 12  is a flow chart illustrating a drying step to be performed in the laundry/drying process in the drum type laundry machine of the embodiment.  
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
      A drum type laundry machine according to one embodiment of the present invention will hereinafter be described with reference to the attached drawings.  
      In  FIG. 1 , a housing  1  defining the outer shape of the drum type laundry machine includes a body  1   a  which has left and right side walls and a rear wall integrally formed and open front, lower and upper faces, an upper face plate  1   b  of a curved frame shape attached to the upper face of the body  1   a , a front face plate  1   c  covering the front face of the body  1   a  and a base  1   d  on which the body  1   a  is mounted. The upper face of the body  1   a  is curved downward from a rear edge to a front edge thereof, and the upper face plate  1   b  is also curved forwardly downward.  
      The upper face plate  1   b  has a laundry loading port  2  provided in a transversely middle portion thereof as longitudinally elongated from a front edge to a rear edge thereof. The front edge of the laundry loading port  2  is located at a height of about 70 cm, for example, as measured from a floor surface, for easy loading and unloading of the laundry.  
      An upper lid  3  for covering and uncovering the laundry loading port  2  is slidable along the laundry loading port  2 . When a user presses a lid opening button  4  provided on a right side of the laundry loading port  2  with the upper lid closed, the upper lid  3  is automatically slid rearward to uncover the laundry loading port  2 . When the opened upper lid  3  is to be closed, the user pulls the upper lid  3  forward by holding a handle  3   a  provided on a front edge of the upper lid  3  by fingers. When the upper lid  3  is completely closed, the upper lid  3  is latched in a closed state by a latch mechanism (not shown).  
      An operation panel  5  is provided on the right side of the upper lid  3  as extending anteroposteriorly. Various operation keys for setting an operation mode, an appointment time and the like and various indicators which are lighted according to the setting and indicate an operation state in a laundry process, the appointment time and a process remaining time are provided in properly spaced relation on the operation panel  5 . Operation keys to be used less frequently are covered with a cover which is opened rearward. A detergent container  6  covered with a cover which is opened laterally is provided on a left rear side of the upper lid  3  opposite from the operation panel  5 . A tap water supply port  7  to be connected to an external water supply through a hose is provided on a rear side of the detergent container  6 , and a bath water supply port  8  for supplying bath water to the laundry machine through a bathwater hose is provided on a rear side of the operation panel  5 .  
      Next, the internal construction of the drum type laundry machine will be described with reference to FIGS.  2  to  8 . An outer tub  9  having a generally cylindrical peripheral wall and generally closed opposite end faces are provided in the housing  1 . The outer tub  9  is disposed with its end faces respectively opposed to the left and right side walls of the housing  1 . The outer tub  9  is suspended at its left and right upper portions by a plurality of springs (not shown), and front and rear lower portions of the outer tub  9  are respectively supported by two dampers  10  in a moderately movable manner. A horizontal drum  11  having a generally cylindrical peripheral wall and generally closed opposite end faces and serving as an inner tub for retaining the laundry is provided in the outer tub  9  rotatably about a horizontal axis C extending laterally. The drum  11  has amultiplicity of water passage holes  12  formed in substantially the entire peripheral wall thereof except for a drum opening (to be described later). Water contained in the outer tub  9  is introduced into the drum  11  through the water passage holes  12 . Further, water squeezed out of the laundry during a dewatering operation is discharged into the outer tub  9  through the water passage holes  12 . Three baffles  13  for lifting the laundry are provided on an inner peripheral surface of the drum  11  in circumferentially equiangularly spaced relation (at intervals of about 120 degrees) as extending transversely and projecting inward from the inner peripheral surface of the drum  11 .  
      A main shaft  14  fixed to the center of the left end face of the drum  11  is supported by a first bearing  16  held by a first bearing case  15  fixed to the left end face of the outer tub  10 . On the other hand, an auxiliary shaft  17  fixed to the center of the right end face of the drum  11  is supported by a second bearing  19  held by a second bearing case  18  fixed to the right end face of the outer tub  9 . The main shaft  14  and the auxiliary shaft  17  define the aforesaid horizontal axis C.  
      A rotor  20   a  of a DC brushless motor  20  of an outer rotor type is attached to a distal end of the main shaft  14  projecting laterally from the left end face of the outer tub  9 , and a stator  20   b  of the motor  20  is fixed to the first bearing case  15  which doubles as a motor base. When a driving electric current is supplied to the stator  20   b  from a control circuit not shown, the rotor  20   a  is rotated by the driving electric current. Thus, the drum  11  is rotatively driven at the same rotation speed as the rotor  20   a  via the main shaft  14 .  
      The outer tub  9  has an outer tub opening  22  formed in an upper portion of the peripheral wall thereof as extending obliquely forward in association with the laundry loading port  2  of the upper face plate  1   b . The outer tub opening  22  is covered and uncovered with a single outer tub lid  21 , which is openable rearward pivotally about an axis extending generally parallel to the horizontal axis C. The drum  11  has a drum opening  24  formed in the peripheral wall thereof. The drum opening  24  is covered and uncovered with a drum lid  23 . The drum lid  23  includes two lid members that are openable away from each other anteroposteriorly pivotally about axes each extending generally parallel to the horizontal axis C.  
      The drum  11  is rotated within the outer tub  9 . At least when the user loads or unloads the laundry in/out of the drum  11 , the drum  11  should be stopped at a rotational position that radially coincides with the outer tub opening  22 . To this end, a drum positioning device  25  is provided on the left end face of the outer tub  9 . The drum positioning device  25  defines a drum stopping position by engagement of an engagement projection projecting from the device  25  with an engagement recess formed in the rotor  20   a  of the motor  20 . Thus, the user can open the upper lid  3 , the outer tub lid  21  and the drum lid  23  to view the inside of the drum from a diagonally upper front side for the loading and unloading of the laundry.  
      A water supply pipe  26  is connected to a rear upper portion of the outer tub  9  slightly above a vertically middle position. The water supply pipe  26  is connected to the detergent container  6 . When a water supply valve  52  (see  FIG. 9 ) is opened, water is supplied into the outer tub  9  through the detergent container  6  and the water supply pipe  26  (e.g., at a water supply rate of about 15 liters per minute). If a detergent is contained in the detergent container  6  at this time, the detergent is supplied together with the water into the outer tub  9 .  
      A drain port  27  is provided in a lowermost portion of the outer tub  9 , and connected to an external drain through a drain valve  28  and a drain hose  29 . When the water is retained in the outer tub  9 , the drain valve  28  is closed. When the drain valve  28  is opened, the water in the outer tub  9  is discharged out of the laundry machine through the drain port  27  and the drain hose  29 .  
      An air circulation passage (drying air passage)  30  for circularly supplying heated drying air into the outer tub  9  during a drying process is provided between the side wall of the housing  1  and an end face portion of the outer tub  9  around the second bearing case  18  on a side of the drum  11  opposite from the motor  20 . The structure of the air circulation passage  30  will be described below in detail.  
      The outer tub  9  includes a body  9   a  unitarily formed of a synthetic resin as having a generally closed left end face and an open right end face, an air outlet port  9   b  provided in a generally transversely middle lower portion of the body  9   a  as communicating with the inside of the outer tub  9 , and a tubular air outlet passage  9   c  provided integrally with the body  9   a  as extending from the air outlet port  9   b  to the right end face of the body  9   a  parallel to the horizontal axis C. The air outlet port  9   b  serves as an exit through which air (drying air) containing moisture is discharged out of the outer tub  9  during the drying process. The air outlet passage  9   c  partly defines the air circulation passage.  
      The outer tub  9  further includes an end face member  9   d  covering the open right end face of the body  9   a  thereof. The end face member  9   d  has a round opening  9   e  in association with an open end face of the air outlet passage  9   c . A dehumidification air passage  31  partly defining the air circulation passage is fixed to the end face member  9   d  as will be described later.  
      The dehumidification air passage  31  has a generally round opening  32   a  formed in a lower end portion thereof as facing laterally. The dehumidification air passage  31  includes an anteroposteriorly flat first air passage  32  extending generally vertically, and a laterally flat second air passage  33  formed integrally with the first air passage  32 . The second air passage  33  communicates with an upper portion of the first air passage  32 , and is bent upward from a laterally extending horizontal portion thereof. The dehumidification air passage  31  has a supply port  34  provided at a position thereof slightly lower than a junction between the first air passage  32  and the second air passage  33 , and a cooling water supply pipe  35  is connected to the supply port  34 . The supply pipe  35  is connected to a cooling water supply valve  53  and, when the supply valve  53  is opened, cooling water (tap water) flows into the first air passage  32  through the supply pipe  35  (e.g., at a water supply rate of about 0.5 liters per minute). Thus, the first air passage  32  serves as a heat exchanger for cooling the drying air containing moisture to condense the moisture into water.  
      The dehumidification air passage  31  is attached to the outer tub  9  with its opening  32   a  engaged with the opening  9   e  of the outer tub  9 . The first air passage  32  is disposed in a space defined between the right end face of the outer tub  9  and the right side wall of the housing  1 , and the second air passage  33  is disposed in a space defined between a rear portion of the body  9   a  of the outer tub  9  and the rear wall of the housing  1 .  
      The second air passage  33  has a projection  36  provided adjacent to an inlet end thereof as projecting inward from a rear interior surface  33   a  thereof. The projection  36  extends vertically and has a chevron shape in cross section. The projection  36  is disposed so that clearances X, Y, Z are respectively defined between the projection  36  and a lower interior surface  33   b , a front interior surface  33   c  and an upper interior surface  33   d  of the second air passage  33 . The projection  36  narrows a downstream portion of the air passage adjacent to the supply port  34 .  
      The second air passage  33  has an outlet opening  37  formed in an outlet end thereof as facing forward. Further, an upper interior surface  33   e  of the second air passage  33  is inclined rearwardly downward so that the air flowing into the second air passage  33  is easily directed toward the outlet opening  37 . A projection  38  (a barrier in the present invention) of a generally chevron shape in cross section is provided on a boundary between the rear interior surface  33   a  and the inclined surface  33   e  of the second air passage  33  as projecting inward and extending laterally and generally horizontally. The projection  38  has aright end portion extending to a right side wall of the second air passage  33 , and a left end portion spaced a predetermine distance from a left side wall of the second air passage  33 .  
      The outlet opening  37  of the second air passage  33  is connected to a rear portion of a blower chamber  40  in which a blower  39  is provided. A blower motor  41  is disposed in front of the blower chamber  40 , i.e., on an upper rear side of the outer tub  9  on a side of the blower chamber  40  opposite from the rear wall of the housing  1 , with an axis F of a motor shaft thereof extending horizontally and generally perpendicularly to the horizontal axis C. The motor shaft of the blower motor  41  is directly connected to the blower  39 .  
      A heater housing  42  which partly defines the air circulation passage is connected to a right side of the blower chamber  40 . The heater housing  42  extends generally horizontally, and is bent generally perpendicularly forward at the outside of the right end face of the outer tub  9  and then generally perpendicularly downward above the auxiliary shaft  18 . A heater  43  including two sheathed line heaters is provided in the heater housing  42  for heating air passing through the heater housing  42 . By energizing one of the sheathed line heaters, the heater  43  is driven at a low level (e.g., at about 700 W). By energizing both of the sheathed line heaters, the heater  43  is driven at a high level (e.g., at about 1400 W). By energizing both of the sheathed line heaters and performing a half-wave control on an alternating current flowing through one of the sheathed line heaters (for allowing the alternating current to flow through the one sheathed line heater in a half cycle), the heater  43  is driven at an intermediate level (e.g., at about 1000 W).  
      An air inlet port  9   f  for introducing the drying air into the outer tub  9  is provided in a portion of the end face member  9   d  of the outer tub  9  covered with the second bearing case  18 . The heater housing  42  communicates with the inside of the outer tub  9  via an opening  18   a  of the second bearing case  18  and the air inlet port  9   f  of the outer tub  9 .  
      An air blowing port  44  is provided in a center portion of the right end face of the drum  11  in opposed relation to the air inlet port  9   f  of the outer tub  9 . The air blowing port  44  includes a plurality of openings  44   a  provided radially around the auxiliary shaft  17  as shown in  FIG. 8 . These openings  44   a  are sufficiently greater in size than the water passage holes  12  provided in the peripheral wall of the drum  11 . The air blowing port  44  is covered with an air blowing port cover  45  provided in front of the air blowing port  44 . The air blowing port cover  45  has air passage holes, which are sufficiently greater in size than the water passage holes  12 . A space between the air inlet port  9   f  and the air blowing port  44  are sealed with a non-contact type seal  46  including a plurality of annular ribs provided on the side of the outer tub  9  and a plurality of annular ribs provided on the side of the drum  11  (a labyrinth seal with the annular ribs on one side and the annular ribs on the other side being arranged in staggered relation). Thus, the drying air and steam (to be described later) are less liable to leak into the space between the drum  11  and the outer tub  9 .  
       FIG. 9  is an electrical block diagram of the drum type laundry machine. A control section  47  principally includes a microprocessor including a CPU, a ROM, a RAM, a timer and the like. The control section  47  performs various control operations for laundry-related operation processes to be described later. The control section  47  is connected to the operation keys  5   a , the indicators  5   b , a water level sensor  48  for detecting the water level of the water retained in the outer tub  9 , a temperature sensor  49  for detecting the temperature of the air flowing out of the outer tub  9  through the air outlet port  9   b , a lid switch  50  for detecting the opening and closing of the upper lid  3 , and the like. The control section  47  is further connected to a load drive section  51 . The control section  47  controls the operations of the motor  20 , the blower motor  41 , the heater  43 , the water supply valve  52 , the supply valve  53 , the drain valve  28  and the like through the load drive section  51 .  
      Next, one exemplary operation process to be performed by the drum type laundry machine having the aforesaid construction will be described with reference to flow charts shown in FIGS.  10  to  12 . The operation process to be herein explained is a standard automatic operation process for continuously performing operations from the start of the laundry process to the end of the drying process. The drum type laundry machine is characterized by a steam washing operation for washing the laundry while supplying steam into the drum  11  in a washing step, and a laundry finishing operation for supplying steam into the drum  11  which contains the laundry substantially completely dried at the last stage of a heat drying step in the drying process. The supply of the steam into the drum  11  is achieved by controlling the heater  43 , the blower motor  41  and the supply valve  53  in a manner different from an ordinary heat drying operation.  
      First, the user opens the upper lid  3 , and then opens the outer tub lid  21  and the drum lid  23  to load the laundry in the drum  11 . Further, the user puts a detergent and a softening agent in the detergent container  6 . When the user performs a starting operation by operating the operation panel  5 , the control section  47  starts the operation process according to the operation of the operation panel  5 . The control section  47  first performs a first washing step (Step S 1 ). The control section  47  opens the water supply valve  52  to supply water into the outer tub  9 . At this time, the drain valve  28  is closed, so that detergent water in which the detergent contained in the detergent container  6  is dissolved is retained in the outer tub  9 . The water retained in the outer tub  9  flows into the drum  11  through the water passage holes  12  and the like, so that the laundry is soaked in the detergent water.  
      When a predetermined water level is reached, the control section  47  drives the motor  20  at a predetermined rotation speed (e.g., 45 rpm) in opposite directions (e.g., ON for 10 seconds and OFF for 3 seconds). The laundry in the drum  11  is lifted by the baffles  13  and dropped from an upper side thereby to be beat-washed. After the beat-washing operation is performed for a predetermined period (e.g., 6 minutes), a second washing step is started.  
      When the second washing step is started (Step S 2 ) the control section  47  opens the drain valve  28  to start draining the water from the drum  11  (Step S 201 ) and switches the rotative driving state (mode) of the drum  11  (Step S 202 ). More specifically, the second washing step is performed in the same ON-OFF cycle as the first washing step, but the rotation speed of the drum  11  is changed with time. The drum  11  is first rotated for a predetermined period (e.g., 3 minutes) at a first rotation speed which is the same rotation speed as in the first washing step for tumbling the laundry, and then rotated for a predetermined period (e.g., 30 seconds) at a predetermined second rotation speed (e.g., 30 rpm) such that the laundry is tumbled only in a bottom portion of the drum  11 . After the drum  11  is rotated at the first rotation speed for the aforesaid predetermined period, the drum  11  is further rotated for a predetermined period (e.g., 30 seconds) at a third rotation speed (e.g., 60 rpm) such that the laundry lightly adheres to the interior surface of the drum  11 . This operation is repeatedly performed. The laundry is beat-washed by the rotation at the first rotation speed, and rub-washed by the rotation at the second rotation speed. By the rotation at the third rotation speed, a dewater-washing operation is performed for squeezing the detergent water together with dirt out of the laundry by a centrifugal force.  
      When the retained water is discharged to a predetermined water level (lower limit water level) with the air outlet port  9   b  at the lower portion of the outer tub  9  opened (not closed by the water) (Step S 203 ), the control section  47  drives the heater  43  at the intermediate level (Step S 204 ) and rotatively drives the blower motor  41  at a preliminary rotation speed (e.g., 3400 rpm) (Step S 205 ). The preliminary rotation speed is lower than a rotation speed (e.g., 4500 rpm) employed for the heat drying operation in the drying process to be described later, and permits speedy increase of the temperature of the heater  43 . The intensity of the heater  43  is adjusted at the intermediate level for the following reason. The laundry in the drum  11  is relatively heavy because it absorbs a great amount of water. Therefore, when the laundry is tumbled, a driving electric current required for the driving of the motor  20  is increased unlike in the drying process. If the heater  43  was driven at the high level, the electric current consumption of the overall laundry machine would exceed the rated current of the laundry machine. The blower  39  is thus rotated to generate air streams, which are circulated through the outer tub  9 , the drum  11  and the air circulation passage  30 .  
      When the temperature of the heater  43  is sufficiently increased with the water level in the outer tub  9  lowered below the bottom of the drum  11  after a lapse of a predetermined period T 1  (e.g., 4 minutes) from the start of the draining of the water (Step S 206 ), the control section  47  increases the rotation speed of the blower motor  41  to a level (hereinafter referred to as “steam supply rotation speed”) which is set higher than the rotation speed for the heat drying operation (hereinafter referred to as “drying rotation speed”) (Step S 207 ). When the rotation speed of the blower motor  41  reaches the steam supply rotation speed after a lapse of a predetermined period T 2  (e.g., 1 minute) (Step S 208 ), the supply valve  53  is opened to supply cooling water into the first air passage  32  from the supply port  34  (Step S 209 ). During the supply of the cooling water, the control section  47  intermittently opens the supply valve  53 . For example, an intermittent valve opening operation in a 10-second ON/110-second OFF cycle is repeated three times.  
      The cooling water flowing into the first air passage  32  through the supply port  34  does not flow downward (upstream) but is mostly sucked upward into the second air passage  33 . This is because the rotation speed of the blower motor  41  is higher than the drying rotation speed to provide higher speed air streams (higher blowing power), and the air passage is narrowed downstream of the supply port  34  by the projection  36  to further increase the flow rate of the air streams in the vicinity of the supply port  34 . The cooling water thus flowing into the second air passage  33  mostly flows through the clearance X between the projection  36  and the lower interior surface  33   b  of the second air passage  33  and then upward in the air passage  33 , and is finely disintegrated into water droplets which are in turn directed toward the outlet opening  37  (as indicated by solid line arrows in  FIG. 6 ). Then, the cooling water (water droplets) is partly introduced into the blower chamber  40  through the outlet opening  37  (as indicated by broken line arrows in  FIG. 6 ). On the other hand, a part of the water flowing upward in the vicinity of the rear interior surface  33   a  of the second air passage  33  hits against the projection  38  disposed at the outlet end thereby to be prevented from further flowing upward, and loses momentum. Then, the water flows back to the exit of the clearance X defined by the projection  36  along the lower interior surface  33   b  of the second air passage  33  (as indicated by solid line arrows in  FIG. 6 ), and are borne on water-containing air streams swiftly flowing out of the clearance X toward the outlet opening  37 . Thus, the water flowing into the second air passage  33  does not entirely flow into the blower chamber  40 , but is partly circulated in the air passage  33  as described above and then moderately flows into the blower chamber  40 .  
      The water droplets introduced into the blower chamber  40  are further borne on the air streams to flow into the heater housing  42 . In the heater housing  42 , the water droplets are brought in contact with the heater  43  to be evaporated into steam. The steam thus generated is borne on the air streams, and flows through the air inlet port  9   f  to be blown into the drum  11  from the air blowing port  44 . As described above, since the supply valve  53  is intermittently opened during the supply of the cooling water, the water supply is periodically stopped. However, as the water circulates in the second air passage  33  during this period, the water droplets gradually flow into the blower chamber  40  and then to the heater  43 . Therefore, the steam is continuously generated, though the amount of the generated steam is gradually reduced. Hence, the steam is continuously supplied into the drum  11  during the supply of the cooling water (for 6 minutes in this embodiment).  
      The laundry absorbing the detergent water and still subjected to the washing operation after the water is discharged out of the drum  11  is heated by the steam introduced into the drum  11 . Thus, the temperature of the laundry is increased. The supply amount and the supply period of the steam, which may vary depending on the ambient temperature and the initial temperature of the detergent water absorbed in the laundry, are determined so that the temperature of the laundry can be increased to about 40° C. during the washing operation with the supply of the steam in this drum type laundry machine.  
      Greasy dirt which is not completely washed off due to a lower water temperature during the first washing step is more easily lifted off by increasing the temperature of the laundry by the steam. Further, the activity of an enzyme contained in the detergent remaining in the laundry is increased. Thus, persistent stain such as of greasy dirt is washed off by various washing operations including the beat-washing operation, the rub-washing operation and the dewater-washing operation. At this time, the drain valve  28  is opened, and the dirt thus washed off is discharged together with the detergent water out of the laundry machine.  
      After the supply of the steam is stopped at the end of the cooling water supply period, the washing operation performed by the rotation of the drum  11  is continued for awhile. After a lapse of a predetermined period T 3  (e.g., 14 minutes) from the start of the second washing step (Step S 210 ), the control section  47  stops the drum  11  (Step S 211 ) to end the second washing step, and starts an intermediate dewatering step.  
      In the intermediate dewatering step, the drum  11  is rotated at a high speed (e.g., 1000 rpm) to squeeze the detergent water out of the laundry (Step S 3 ). The water squeezed out of the laundry is discharged into the outer tub  9  through the water passage holes  12  and then out of the laundry machine through the drain hose  29 .  
      After the completion of the intermediate dewatering step, a rinsing step is performed for beat-rinsing the laundry while rotating the drum  11  at a lower rotation speed with a predetermined amount of water retained in the drum  11  as in the first washing step, followed by the intermediate dewatering step. This operation is repeated a plurality of times (e.g., twice) (Step S 4 ). Then, a final dewatering step is performed to dewater the laundry as in the intermediate dewatering step (Step S 5 ). A dewatering period for the final dewatering step is sufficiently longer than that for the intermediate dewatering step so as to provide a satisfactory dewatering efficiency.  
      Upon the completion of the final dewatering step, the drying process is started (Step S 6 ). The control section  47  rotatively drives the drum  11  (Step S 601 ), and drives the heater  43  and the blower motor  41  (Steps S 602 , S 603 ). Further, the control section  47  opens the supply valve  53  (Step S 604 ). Thus, the heat drying operation is started for drying the laundry by hot drying air. In the heat drying operation, the rotation speed of the blower motor  41  is set at the aforesaid drying rotation speed (e.g., 4500 rpm), and the intensity of the heater  43  is set at the high level.  
      When the blower  39  is rotatively driven by the blower motor  41 , the blower  39  laterally blows the air sucked from the rear side thereof. Therefore, drying air streams directed from the blower chamber  40  to the heater housing  42  are generated, and heated by the heater  43  when passing through the heater housing  42 . The resulting hot drying air flows into the drum  11  from the air blowing port  44  through the air inlet port  9   f . The drying air flowing into the drum  11  passes through gaps between pieces of the laundry and gaps between fibers of the laundry thereby to remove moisture from the laundry. Then, the drying air sufficiently containing moisture mainly flows out of the drum  11  through the water passage holes  12 , and is directed toward the air outlet port  9   b  through the space defined between the drum  1  and the outer tub  9 . The drying air discharged out of the outer tub  9  through the air outlet port  9   b  and containing a great amount of moisture reaches the dehumidification air passage  31  through the air outlet passage  9   c  and flows upward in the first air passage  32 .  
      The cooling water supplied into the first air passage  32  mostly flows down into the first air passage  32  because the rotation speed of the blower  39  at this time does not provide an air flow rate sufficient to suck the water upward. That is, the cooling water flows in a direction opposite to the direction of the drying air flowing in the first air passage  32 . The humid drying air is rapidly cooled by heat exchange with the cooling water. As a result, the moisture contained in the drying air is condensed into water on the interior surface of the first air passage  32 , and the water flows down along the interior surface of the first air passage  32 . Therefore, the drying air is dehumidified while passing through the first air passage  32 , and the resulting dry air flows back into the blower chamber  40  through the second air passage  33 . Then, the drying air is introduced again into the heater housing  42  by the blower  39  thereby to be heated again by the heater  43 .  
      The water condensed on the interior surface of the first air passage  32  flows together with the cooling water into the air outlet passage  9   c  from the opening  9   e , and then flows into the outer tub  9  along the moderate inclination of the bottom of the air outlet passage  9   c . Finally, the water is discharged out of the laundry machine through the drain port  27 .  
      A very small amount of the cooling water supplied into the first air passage  32  may be sucked into the second air passage  33 . In this case, the cooling water sucked into the second air passage  33  is directed toward the outlet opening  37  along the rear interior surface  33   a  of the second air passage  33 , though the air streams do not have sufficient momentum. However, the water (water droplets) flowing upward is blocked by the projection  38  which is disposed at the outlet end of the second air passage  33 . Therefore, the water is prevented from flowing into the blower chamber  40 .  
      The temperature of the air discharged from the air outlet port  9   b  is kept generally constant when heat is sufficiently exchanged between the wet laundry and the hot drying air in the drum  11 , but increased when the laundry becomes dry and the heat exchange does not sufficiently occur. Therefore, the control section  47  judges the dryness level of the laundry on the basis of the discharged air temperature detected by the temperature sensor  49 . When the control section  47  determines that the laundry dryness level reaches a predetermined level (Step S 605 ) the heat drying operation is further continued for an extension period which is determined according to an automatic operation period required for reaching the predetermined dryness level (Step S 606 ). When the automatic operation period is longer, it is supposed that a greater amount of laundry is present in the drum  11  and, therefore, the extension period is set longer.  
      When the process enters the extension period, the control section  47  increases the rotation speed of the blower motor  41  from the drying rotation speed to the steam supply rotation speed for a predetermined period T 4  (e.g., 20 seconds), while keeping the output of the heater  43  at the high level (Steps S 607  to S 609 ). Thus, the water droplets in a mist form are carried into the heater  43 , and heated by the heater  43  for the generation of the steam, which is introduced into the drum  11 . Thus, the steam is applied to the dried laundry in the drum  11 , whereby the laundry is unwrinkled and softened with fibers thereof raised. Further, static electricity is suppressed.  
      If the extension period is relatively long, the supply of the steam is repeated up to an upper limit number of times (e.g., three times at the maximum) during a predetermined period T 5  (e.g., 2 minutes) (steps S 610  to S 612 ). Where the extension period is set to 4 minutes, 8 minutes or 15 minutes, for example, the supply of the steam occurs once in an extension period of 4 minutes, twice in 8 minutes, and three times in 15 minutes. This is because the extension period is set longer when the amount of the laundry is great and, in this case, the number of times for the finishing of the laundry with the steam is preferably increased.  
      After a lapse of the extension period (YES in Step S 610 ), the control section  47  stops the heater  43  to end the heat drying operation (Step S 613 ). After a cooling operation is performed for cooling the laundry only by supplying air from the blower  39 , the control section  47  stops the blower  39  and the drum  11  to end the drying process (Steps S 614 , S 615 ). Thus, the laundry/drying process is completed.  
      As described above, the drum type laundry machine performs the first washing step for washing the laundry in the detergent water contained in the drum  11  and, after the water is drained out of the drum  11 , performs the second washing step for washing the laundry absorbing the detergent water while warming the laundry by the steam. Therefore, the drum type laundry machine has an improved washing capability. In addition, a relatively small amount of the detergent water absorbed in the laundry after the draining of the water is warmed by the effect of the steam without the need for a great amount of heat. Consequently, the washing capability can be improved with reduced power consumption.  
      The steam is generated by utilizing the air blowing means (the blower  39  and the blower motor  41 ) and the heating means (the heater  43 ) which are originally provided for heat-drying the laundry, and the cooling water supplying means (the supply valve  53  and the supply pipe  35 ). Therefore, the arrangement for the generation of the steam can be provided at lower costs.  
      Further, the steam is introduced into the drum  11  not through the small water passage holes  12  provided in the peripheral wall of the drum  11  but through the dry air blowing port  44  which is provided in the one end face of the drum  11  and is greater in size than the water passage holes  12 . Therefore, the steam can be sufficiently supplied into the drum  11 . Further, the steam is blown into the drum  11  from the center portion of the one end face of the drum  11 , so that the steam can be evenly applied to the laundry tumbled in the drum  11 .  
      In the second washing step in which the steam is supplied for a relatively long period, the cooling water is intermittently supplied for the supply of the steam. This prevents a steam generation failure which may otherwise occur when a great amount of water (water droplets) is continuously applied to the heater  43  to reduce the temperature of the heater  43 .  
      Further, the projection  36  is provided downstream of the cooling water supply port  34  in the vicinity of the cooling water supply port  34  to narrow the air passage, whereby the flow rate of the air is increased in the vicinity of the supply port  34 . Thus, the water flowing through the supply port  34  can be easily sucked into the downstream second air passage  33  during the generation of the steam. Therefore, the water can be supplied to the heater  43  without the need for extremely increasing the blowing power of the blower  39 .  
      The projection  38  is disposed in the vicinity of the outlet opening  37  of the second air passage  33 . Therefore, even if the cooling water is partly supplied to the downstream second air passage  33  during the ordinary heat drying operation, the cooling water is blocked by the projection  38 . Thus, the water is prevented from being supplied to the heater  43  when unnecessary. Since the amount of the water directed toward the heater  43  can be properly adjusted by the projection  38 , it is possible to prevent the supply of a great amount of water to the heater  43  at a time and hence to prevent the reduction in the temperature of the heater  43 .  
      If the clearances Y, Z defined between the projection  36  and the interior surfaces of the air passage are too large, a greater amount of air is introduced through the clearances Y, Z, and the flow rate of the air flowing through the clearance X is reduced. This reduces a suction force for sucking the cooling water into the second air passage  33  during the supply of the steam. On the other hand, if the clearances Y, Z are too small, it is impossible to supply a sufficient amount of air during the ordinary heat drying operation, thereby reducing the drying capability. In view of this, the clearances Y and Z are experimentally determined so as not to reduce the cooling water suction force and the drying capability. If the clearance X is changed, the direction of the water flowing out of the clearance X during the supply of the steam is changed. Further, the flow rate is also changed. In view of this, the clearance X is experimentally determined so as to provide a flow rate sufficient to properly direct the water toward the outlet opening  37 .  
      In the embodiment described above, the dewatering step is started immediately after the completion of the rinsing step. Alternatively, a steam heating step for warming the laundry by supplying the steam into the drum  11  while rotating the drum  11  may be performed at least before the start of the final dewatering step after the water is drained out of the drum  11 .  
      With this arrangement, the dewatering operation can be performed after the temperature of the laundry is increased upon the completion of the rinsing step. Therefore, the water more easily permeates the laundry, and the dewatering capability is improved. In addition, a relatively small amount of water absorbed in the laundry after the draining of the water is warmed by the effect of the steam without the need for a great amount of heat. Therefore, power consumption can be reduced.  
      The embodiment described above is merely an example of the present invention and, apparently, modifications and alterations may be made within the scope of the present invention. In the embodiment described above, the present invention is applied to the drum type laundry machine, but is applicable to a laundry machine which includes a cylindrical laundry/dewatering tub having a closed bottom and rotatable about a vertical axis or an axis inclined with respect to the vertical axis. Further, the present invention is applicable to a laundry machine which does not have a hot air drying function.  
      This application corresponds to Japanese Patent Application No. 2004-142873 filed with the Japanese Patent Office on May 12, 2004, the disclosure of which is incorporated herein by reference.