Abstract:
The present invention relates to a steam generator and a washing machine therewith. The present invention provides a steam generator including a water chamber for holding water, the water chamber having a heater mounted thereto for heating the water, a steam chamber for holding steam generated as the water chamber, and steam water is heated, a water supply line for supplying the water to the water chamber, and a steam discharge line for discharging steam from the steam chamber, wherein the water chamber has a vertical direction length (a vertical length) relatively greater than a horizontal direction length (a horizontal length); and a washing machine therewith.

Description:
[0001]     This application claims the benefit of the Patent Korean Application No. 10-2006-0008545, filed on Jan. 26, 2006, which is hereby incorporated by reference as if fully set forth herein.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to washing machines, and more particularly, to a steam generator for supplying steam to a washing machine, and a washing machine therewith.  
         [0004]     2. Discussion of the Related Art  
         [0005]     In general, in the washing machines, there are pulsator type washing machines in which washing is made by a water circulation generated by a rotating pulsator, drum type washing machines in which washing is made by head and friction of washing water and laundry formed inside of a drum as the drum laid substantially in a horizontal direction is rotated, and agitator type washing machines in which washing is made by using rotation force of an upright agitator.  
         [0006]     In the meantime, recently, a washing machine, particularly, a drum type washing machine is suggested, in which washing and the like are made with steam. If the washing is made with the steam, water and electricity can be saved, the washing performance can be enhanced, and generation of static electricity can be prevented. Moreover, wrinkle and smell can be removed from the laundry.  
         [0007]     A related art drum type washing machine with a steam generator will be described, with reference to  FIG. 1 .  
         [0008]     The related art drum type washing machine is provided with a cabinet  10  which forms an exterior of the washing machine, a cylindrical tub  20  supported in a horizontal direction in the cabinet  10  for holding washing water, a drum  30  rotatably mounted in the tub  20 , and a driving motor (not shown) for driving the drum  30 . The cabinet  10  has a laundry opening  13  in a front in communication with an inside of the drum for introduction/taking out laundry to/from the drum  30 , with a door  11  mounted thereon for opening/closing the laundry opening  13 . At one side of the drum type washing machine, there is a water supply valve  15  connected to an external water pipe (not shown) for supplying washing water to the tub  20 . In general, between a detergent box  27  and the water supply valve  15 , there are a hot water pipe  25   a  and a cold water pipe  26  connected thereto.  
         [0009]     In the meantime, in the related art drum type washing machine, there is a steam generator  50  for supplying the steam to the inside of the drum  30 , with a water supply hose  25  for supplying water and a steam hose  53  for supplying steam to the drum  30  connected thereto. In general, the water supply hose  25  is connected to a hot water side of the water supply valve  15 . It is preferable that the steam hose  53  has a nozzle shaped end for smooth spray of the steam into an inside space of the drum  30 , preferably with the nozzle shaped end through which the steam is sprayed exposed to the inside of the drum  30 .  
         [0010]     The steam generator  50  will be described in more detail with reference to  FIGS. 2 and 3 .  
         [0011]     The steam generator  50  is provided with a lower housing  81  which forms an exterior of the steam generator  50  and a space for holding water, an upper housing  82  secured to an upper side of the lower housing  81 , and a heater  55  for heating the water in the steam generator  50 .  
         [0012]     At one side of the upper housing  82 , there is a water supply opening  52   b  connected to the water supply hose  25  for supply of the water to an inside of the steam generator  50 , and at the other side of the upper housing  82 , there is a steam discharge opening  52   a  connected to the steam hose  53  for supplying the steam to the drum  20 .  
         [0013]     The heater  55 , mounted on a bottom of the lower housing  81 , is operated in a state fully submerged in the water when the water is introduced into the steam generator  50 . For this, mounted to one side of the upper housing  82 , there is a water level sensor  60  for sensing a water level of the water held in the steam generator  50 . The water level sensor  60  measures the water level inside of the steam generator  50  for always maintaining an appropriate level of the water. That is, if the water level in the steam generator  50  is lower than a reference value (a low water level), the water supply valve  15  is opened, to supply the water, and, if the water level of the inside of the steam generator  50  reaches to a reference value (high water level), the water supply valve  15  is closed, to stop supply of the water, and the heater  55  is put into operation, to generate the steam.  
         [0014]     In the meantime, there is a temperature sensor  57  mounted thereto for measuring temperatures of the water heated by the heater  55  and the steam. The temperature sensor  57  is used for turning off power to the heater  55  to prevent the heater  55  from overheating if the temperature of the steam generator  50  measured by the temperature sensor  57  is higher than a reference value.  
         [0015]     The water level sensor  60  will be described.  
         [0016]     The water level sensor  60  is provided with a receptacle housing  61  which forms an exterior of the water level sensor  60  and provided for securing the water level sensor  60  to the steam generator  50 , electrodes  62 ,  63 , and  64  under the receptacle housing  61  for sensing water levels of the steam generator  50 . In order to sense water levels of the steam generator  50 , the electrodes  62 ,  63 , and  64  are mounted to appropriate heights from the bottom of the lower housing  81 . The electrodes are a common electrode  62  which is a reference electrode for sensing a minimum water level, a low water level electrode  63  for sensing a low water level, and a high water level electrode  64  for sensing a high water level. It is preferable that the common electrode  62  has a length at least the same with or longer than the low water level electrode  63 .  
         [0017]     In the meantime, if the water boils, many bubbles are formed suddenly, which are liable to stick to the electrodes  62 ,  63 , and  64 , to cause malfunction of the steam generator  50 . Moreover, the water supplied through the water supply opening  122  is liable to splash to the electrodes, to cause malfunction of the steam generator. Moreover, it is difficult to avoid a certain level of vibration during operation of the washing machine, which is liable to cause washing of the water in the stream generator. Therefore, in order to prevent the water level sensor  70  from malfunctioning due to those, the water level sensor  70  is provided with a housing  70 . Basically, the housing  70  surrounds the electrodes  62 ,  63 , and  64  and an opened bottom. It is preferable that the housing  70  has an opening  70   s.    
         [0018]     However, the related art steam generator in a washing machine and a washing machine therewith has the following problems.  
         [0019]     Referring to  FIG. 5 , the related art steam generator is rectangular substantially, with a low height L 1  and a large width L 12 . Therefore, it is not easy to mount the steam generator to the washing machine. Because, though the steam generator in general mounted to an upper portion of the washing machine, i.e., between the cabinet and the tub, a space τ between the tub and the steam generator is not large. Moreover, because valves, hanging springs, and the like are mounted in the space between the cabinet and the tub, there is not so large surplus space. Accordingly, in the related art, mounting of the steam generator is not easy, and the steam generator suffers from damage caused by interference during movement of the washing machine. Moreover, because there is comparatively small gap, the steam generator is liable to collide to suffer from damage due to vibration coming from operation of the washing machine. Moreover, replacement of components is not easy.  
         [0020]     On the other hand, it is required to improve performances of the steam generator, such as water consumption, energy efficiency, a steam generating time period, safety, and the like.  
       SUMMARY OF THE INVENTION  
       [0021]     Accordingly, the present invention is directed to a steam generator and a washing machine therewith.  
         [0022]     An object of the present invention is to provide a steam generator and a washing machine therewith which enables easy mounting of the steam generator.  
         [0023]     Another object of the present invention devised to solve the problem lies on providing a steam generator which can improve performances of a steam generator and a washing machine, and a washing machine therewith.  
         [0024]     Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.  
         [0025]     To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a steam generator includes a water chamber for holding water, the water chamber having a heater mounted thereto for heating the water, a steam chamber for holding steam generated as the water is heated, a water supply line for supplying the water to the water chamber, and a steam discharge line for discharging steam from the steam chamber, wherein the water chamber has a vertical direction length (a vertical length) relatively greater than a horizontal direction length (a horizontal length). Preferably, the steam chamber has a horizontal direction length (a horizontal length) relatively greater than the horizontal length of the water chamber. Preferably, the steam generator further includes a reverse flow preventive member provided to at least one of the water supply line and the steam discharge line, for preventing the water and the steam from flowing in a reverse direction. The reverse flow preventive member may be a nozzle shaped flexible member.  
         [0026]     In another aspect of the present invention, a steam generator includes a water chamber for holding water, the water chamber having a heater mounted thereto for heating the water, a steam chamber for holding steam generated as the water is heated, a water supply line for supplying the water to the water chamber, and a steam discharge line for discharging steam from the steam chamber, wherein a safety valve is provided to a predetermined position of the steam discharge line for automatic opening in a case a steam pressure is higher than a predetermined value. Preferably, the water chamber has a vertical direction length (a vertical length) relatively greater than a horizontal direction length (a horizontal length). More preferably, the steam chamber has a horizontal direction length (a horizontal length) relatively greater than the horizontal length of the water chamber.  
         [0027]     In another aspect of the present invention, a steam generator includes a water chamber for holding water, the water chamber having a heater mounted thereto for heating the water, a steam chamber for holding steam generated as the water is heated, wherein the water chamber has a drain portion, having an opening/closing member provided thereto for automatic opening/closing of the drain portion. Preferably, the water chamber has a vertical direction length (a vertical length) relatively greater than a horizontal direction length (a horizontal length). More preferably, the steam chamber has a horizontal direction length (a horizontal length) relatively greater than the horizontal length of the water chamber. The opening/closing member is a solenoid valve or fabricated by utilizing the siphon principle.  
         [0028]     In another aspect of the present invention, a washing machine includes a cabinet which forms an exterior of the washing machine, a tub supported in the cabinet for holding washing water, a drum rotatably mounted in the tub, and a steam generator for supplying steam to the drum. One of the foregoing steam generators is applicable to the washing machine. Preferably, the steam generator is mounted in a space between an upper portion of an inside of the cabinet and an upper portion of an outside of the tub.  
         [0029]     Thus, the steam generator of the present invention has the following advantages.  
         [0030]     First, the horizontal length of the water chamber shorter than a vertical length thereof permits easy mounting of the steam generator.  
         [0031]     Second, performances of the steam generator and the washing machine are enhanced owing to the smaller water consumption and faster generation of steam than the related art steam generator.  
         [0032]     Third, a reverse flow of the water and the steam can be prevented, effectively. Safety of the steam generator is improved as the safety valve will be opened in a case the steam generator is over pressurized due to detect at the steam supply line.  
         [0033]     Fourth, malfunction of the water level sensor can be prevented, effectively.  
         [0034]     Fifth, splashing of the water from the steam generator to the drum can be prevented, permitting to prevent stains from forming on the laundry.  
         [0035]     It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0036]     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:  
         [0037]      FIG. 1  illustrates a perspective view of a related art drum type washing machine.  
         [0038]      FIG. 2  illustrates a perspective view of a steam generator in  FIG. 1 .  
         [0039]      FIG. 3  illustrates a perspective view of the steam generator in  FIG. 2  with a partial cut-away view.  
         [0040]      FIG. 4  illustrates a perspective view of the water level sensor in the steam generator in  FIG. 2 .  
         [0041]      FIG. 5  illustrates a conceptual drawing showing mounting of the steam generator in  FIG. 1 .  
         [0042]     FIGS.  6  to  9  illustrate conceptual drawings each for describing a principle of the steam generator in accordance with a preferred embodiment of the present invention, equivalent to  FIG. 5 .  
         [0043]      FIG. 10  illustrates a detailed perspective view of the steam generator in  FIG. 6 .  
         [0044]      FIG. 11  illustrates an underside view of the upper housing in  FIG. 10 .  
         [0045]      FIG. 12  illustrates a section of  FIG. 10 .  
         [0046]      FIG. 13  illustrates a mounted state of a reverse flow preventive member in accordance with a preferred embodiment of the present invention.  
         [0047]      FIG. 14  illustrates a mounted state of a safety valve in accordance with a preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0048]     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.  
         [0049]     A principle of a steam generator in accordance with a preferred embodiment of the present invention will be described with reference to  FIG. 6 .  
         [0050]     Basically, the steam generator  100  includes a water chamber W for holding water, and having a heater  200  mounted therein for heating the water, and a steam chamber S for holding the steam from the water heated by the heater  200 . That is, the steam is generated as the water in the water chamber W is heated by the heater  200 , and the steam is held in the steam chamber S temporarily, and discharged to an outside of the steam generator through a steam outlet in the steam chamber S.  
         [0051]     Referring to  FIG. 5 , the related art steam generator  50  which is rectangular has a water chamber W with a horizontal length L 2  relatively greater than a vertical length L 3 . That is, the related art steam generator  50  with the heater  55  mounted in horizontally has a vertical length of the water chamber W in a range of a thickness of the heater  55 . That is, a horizontal length is made greater, to meet a water capacity requirement. Opposite to this, the steam generator of the present invention has the vertical length L 4  of the water chamber W relatively greater than the horizontal length L 5  actually. Accordingly, the heater  200  is also mounted in a vertical position actually. As can be known from  FIG. 6 , even though the vertical length of the water chamber W may be taken as a length L 4   a  of a portion the heater  200  is mounted thereto actually, the vertical length of the water chamber W may be taken as a vertical length L 4  because it is preferable that the water is filled slightly above the heater  200 . Because a difference between L 4  and L 4   a  is not so much great, most of water in the water chamber W is up to L 4   a . Moreover, under the same reason, a horizontal length of the water chamber W is L 5  which is a width of a portion that takes most portion of the water chamber W which holds the water, actually.  
         [0052]     The steam generator of the present invention has the following advantages. Since the horizontal length L 5  can be reduced compared to the related art steam generator while holding the same amount of water, interference between the tub  20  and the steam generator  100  can be reduced. It is known from the inventor&#39;s experiment that the present invention can reduce water consumption and a steam generating period in a case an amount of steam the same with the related art is generated. Accordingly, on the whole, the present invention can reduce a size of the steam generator  100 .  
         [0053]     In the meantime, it is preferable that the horizontal length L 6  of the steam chamber S is relatively greater than the horizontal length of the water chamber W. That is, though the horizontal length L 6  of the steam chamber S can also be reduced compared to the related art, it is preferable that the horizontal length L 6  of the steam chamber S is the same with or slightly smaller than the related art. Because in general the steam chamber S has a water supply opening and a steam discharging opening, and has the water level sensor and the temperature sensor mounted thereto.  
         [0054]     In the meantime, the vertical length L 4  of the water chamber W can be made relatively smaller than the horizontal length L 5  in a variety of schemes. For an example, as shown in FIGS.  6  to  8 , the horizontal length of the water chamber W may be fixed in a vertical direction. In those cases, as shown in  FIG. 8 , the water chamber W may be sloped with respect to the steam chamber S at a predetermined angle. As shown in  FIGS. 6 and 7 , in view of fabrication of the steam generator  100 , it is preferable that the water chamber W is not sloped with respect to the steam chamber S. In this case, as shown in  FIG. 6 , it is preferable that the water chamber W is at a center of the steam chamber S, substantially.  
         [0055]     Referring to  FIG. 9 , the horizontal length of the water chamber W may become the smaller as it goes downward the more. It is known from an inventor&#39;s experiment that the steam generator in anyone of FIGS.  6  to  8  has a lower water consumption compared to the steam generator in  FIG. 9 , and the steam generator in anyone of FIGS.  6  to  8  has a shorter steam generating period than the steam generator in  FIG. 9 . This is because the steam generator in  FIG. 9  holds more water in a case the same size of heaters are used.  
         [0056]     In the meantime, it is preferable that the steam generator  100  includes a lower housing which serves as a water chamber W actually, and an upper housing which is secured to a top of the lower housing and serves as a steam chamber S, actually. Of course, depending on a position of fastening of the upper housing to the lower housing, the water chamber W and the steam chamber S may share functions of the water chamber W or the steam chamber S to a certain extent, the lower housing serves as the water chamber W mostly, and the upper housing serves as the steam chamber S mostly.  
         [0057]     A steam generator  100  equivalent to one in  FIG. 6  will be described with reference to  FIG. 10 .  
         [0058]     The steam generator  100  includes an upper housing  110  and a lower housing  120 . The upper housing  120  has a horizontal length greater than a horizontal length of the lower housing. The lower housing  110  has a portion (for convenience sake called as a main portion)  111  having the heater  200  mounted thereto and a vertical length greater than a horizontal length for holding the water mostly, and a portion (for convenience sake called as a connection portion)  112  and  114  extended to opposite directions from the main portion  111  and fastened to the upper housing  120  (see  FIG. 12 ). The water is mostly held in the main portion  111  of the water chamber W, it is preferable that a portion of the water is held in the connection portions  112 , and  114 , and it is preferable that the connection portions  112  and  114  are sloped toward the main portion  111 . By forming thus, deposit of scale on the water level sensor  300  can be prevented  
         [0059]     Since the present invention has relatively higher steam pressure and temperature than the related art, it is preferable that the steam generator is formed of a material which can endure the pressure and temperature. Therefore, it is preferable that the lower housing  110  and the upper housing  120  are fastened together, not by thermal fusion, but by vibratory fusion.  
         [0060]     The upper housing  120  which mostly serves as the steam chamber S will be described, with reference to  FIGS. 10 and 11 .  
         [0061]     The upper housing  120  has a water supply opening  122  and a steam discharge opening  124 . It is preferable that the upper housing  120  has a portion projected upward, in which the water supply opening  122  and the steam discharge opening  124  are formed therein.  
         [0062]     The upper housing  120  has the water level sensor  300  and the temperature sensor  400  mounted thereto. It is preferable that the water level sensor  300  is positioned a predetermined distance away from the water supply opening  122 , for an example, away from a water supply direction of the water supply opening  122 . By doing thus, malfunction of the water level sensor  300  can be prevented because water splash from the water supply opening  122  to the water level sensor  300  can be prevented. Moreover, it is preferable that the water level sensor  300  is positioned adjacent to an inside wall of the upper housing  120 , i.e., over the connection portion  112 , or  114 , rather than over the main portion  111  of the lower housing  110 . In another point of view, it is preferable that the water sensor  300  is spaced a predetermined distance from the main portion  111  of the water chamber W. By doing thus, splash of water and bubbles to the water level sensor  300 , which causes malfunction of the water level sensor  300 , can be prevented effectively at the time the heater  200  at the main portion  111  of the water chamber W heats, particularly, at the time the heater  200  starts to heat.  
         [0063]     In the meantime, there is a housing  320  for housing the water level sensor  300 , preferably constructed of a wall. Though the wall may be constructed separately on the whole like the related art, it is preferable that an inside wall of the steam generator  100  serves as a portion of the wall. That is, it is preferable that the wall includes a long wall  324  substantially parallel to the water level sensor  300 , and one pair of short walls  322  each having one side connected to the long wall  324 , and the other side connected to an inside wall of the upper housing  120 . It is preferable that the long wall  324  is positioned over the connection portions  112  and  114  of the lower housing  110 , and positioned at a boundary (a position of a wall of the main portion  111  of the lower housing  110  substantially) of the main portion  111  and the connection portion  112  and  114  of the water chamber W.  
         [0064]     In the meantime, if the housing  320  has a great height, the housing  320  has an opening  326  for free flow of water from/to the water chamber W. It is preferable that the opening  326  is formed adjacent to the inside wall of the steam generator  100 , i.e., at a fore end of the short wall  324 .  
         [0065]     In the meantime, for effective prevention of water and bubbles from splashing to the water level sensor  300 , it is preferable that a supplementary wall  330  is further provided on an outer side of the housing  320 . It is preferable that the supplementary wall  330  is arranged to surround a portion of the housing  320 , for an example, one of the short walls  322 . It is preferable that the supplementary wall also has an opening  332  for free flow of the water from/to the water chamber W, and more preferably adjacent to an inside wall of the steam generator  100 . In this instance, it is preferable that the opening  332  is extended to a bottom of the upper housing  120 .  
         [0066]     In the meantime, the water level sensor  300  includes a common electrode  312 , a low water level electrode  314 , and a high water level electrode  316 , and it is preferable that the high water level electrode  316  is spaced a predetermined distance away from the low water level electrode  314 . In such a case, since a standard product having a common electrode, a high water level electrode, and a low water level electrode is in general used as the water level sensor  300 , it is preferable that a general water level sensor  300  assembly is used as it is, except that the high water level electrode  316   a  of the water level sensor assembly is not used, but a separate high water level electrode  316  is used. It is preferable that a high water level electrode housing  318 , for an example, a cylindrical wall is further provided for housing the high water level electrode  316  positioned away from other electrodes. By doing thus, malfunction of the water level sensor  300  caused by dew between the high water level electrode  314  and the low water level electrode  316  can be prevented.  
         [0067]     In the meantime, as described before, the upper housing  120  has a discharge opening  124  for discharging the steam. The discharge opening  124  is provided with a separator  420  for isolating a space the steam is discharged to an outside actually from other space. At the time the water is heated in the water chamber W, particularly at an initial stage of the heating, since the water and bubbles splash heavily, the separator  420  prevents the water from splashing into the drum through the discharge opening  124 . If the water splashes onto laundry, stains can appear on the laundry, which can be prevented by the separator  420 .  
         [0068]     It is required that the separator  420  can be placed in the discharge opening  124 , and allows the steam to flow. It is preferable that the separator  420  is walls, preferably with openings  421 . Though there is no limitation in shapes of the walls, it is preferable that the openings are form in a vertical direction. It is more preferable that the opening  421  is positioned spaced a predetermined distance away from the steam discharge opening  124 .  
         [0069]     The walls substantially include a first wall  424  opposite to the steam discharge opening  124 , and a second wall  422  extended from the first wall  424  toward the steam discharge opening  124 . Though the first wall  424  and the second wall  422  can be formed as one body, it is preferable that the first wall  424  and the second wall  422  may be one pair of walls separated from each other, with the opening  421  formed between the first wall  424  and the second wall  422 . It is preferable that the first wall  424  is formed, not over the main portion  111 , but over the connection portion  112  or  114  of the water chamber W.  
         [0070]     In the meantime, it is preferable that the separator  420  further includes a supplementary separator  430 , for an example, a wall, on an outer side. It is preferable that the wall of the supplementary separator  430  is positioned adjacent to the opening  421  of the separator  420 . It is preferable that the wall of the supplementary separator  430  is not in contact with the inside wall of the steam generator  100 .  
         [0071]     In the meantime, as described before, the water is supplied to the water chamber W through a water supply line, such as the water supply hose, the water supply opening  122 , and the steam is discharged from the steam chamber S through a steam discharge line, such as the discharge opening  124 , and the steam hose. It is preferable that a reverse flow preventive member is provided to at least one of the water supply line and the steam discharge line for preventing the water and the steam from flowing in a reverse direction. The reverse flow preventive member may be anyone that has a reverse flow preventing function, such as an one-way valve. However, because the reverse flow preventive member is mounted on the water supply hose, the water supply opening  122 , the discharge opening  124 , the steam discharge pipe, all of which have comparatively small diameters, it is preferable that the reverse flow preventive member is a f nozzle shaped flexible member  600  as shown in  FIG. 13 . It is preferable that the reverse flow preventive member has a cut-opened portion  610  in a nozzle shaped portion.  
         [0072]     In the meantime, referring to  FIG. 14 , it is preferable that a safety valve  700  is provided to a predetermined position of the steam discharge line for making automatic opening in a case a steam pressure is higher than a predetermined value. It is preferable that the steam hose  53  is branched to form a branch pipe  53   a , and the safety valve  700  is mounted to the branch pipe  53   a . The steam supply line can be over pressurized if the steam is not supplied to the drum due to defect in the steam supply line. In this case, the safety valve  700  is opened automatically, to discharge the steam to an outside of the steam generator.  
         [0073]     In the meantime, referring to  FIG. 12 , the water chamber W has a drain portion  112  for discharging water from the water chamber W to an outside of the steam generator, with an opening/closing member  113  provided thereto for opening/closing the drain portion  112 . By opening the opening/closing member  113 , the water can be drained from the water chamber W to an outside of the steam generator. In general, if the steam generator  100  is used for a long time, scale deposits on the steam generator  100 . However, if the water is drained from the water chamber W to an outside of the steam generator by opening the drain portion  112 , the deposition of the scale can be prevented because the water carries away material of the scale.  
         [0074]     Though the opening/closing member  113  can be a drain cap which can be opened/closed manually by a user or a service man, an automatic opening/closing member  113  can be used. For an example, the opening/closing member may be a solenoid valve. Moreover, the opening/closing member may be fabricated by using the siphon principle.  
         [0075]     In the meantime, it is apparent that inside structures of the steam generator of the present invention described above, such as the wall for the water level sensor, the supplementary wall, the separator, the reverse flow preventive member, the opening/closing member, and the like are applicable to the related art steam generator.  
         [0076]     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. For an example, the steam generator of the present invention is also applicable to a dryer which uses steam.