Abstract:
For use in an electric home appliance, such as steam mop or steam vacuum cleaner, a steam generator is disclosed to include an electric heater, a fluid storage tank connected to the electric heater, a pressure valve installed in the fluid storage tank and an air compression unit operable by hand, electricity or steam to pump air into the fluid storage tank to force fluid out of the fluid storage tank to the electric heater for heating into steam for application.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    (a) Field of the Invention 
         [0002]    The present invention relates to apparatus for generating steam and more particularly, to a steam generator practical for use in an electric home appliance, such as steam mop or steam vacuum cleaner. 
         [0003]    (b) Description of the Prior Art 
         [0004]    Some electric home appliances, such as steam mop, steam vacuum cleaner and steam iron, need to use steam. These electric home appliances commonly have a steam generator mounted therein for generating steam. A steam generator is know, as show in  FIG. 1 , comprising a heating core  10 , a water tank  20  and a manual or electric water pump  30 . The heating core  10  can be, for example, an electric heater tube that generates heat when electrically connected. The water tank  20  has a water pipe  201  connected to the heating core  10 . The water pump  30  is installed in the bottom side of the water tank  20  or the water pipe  201  for pumping water out of the water tank  20 . When used in an electric home appliance, the water pump  30  is operated manually or electrically to pump water out of the water tank  20  through the water pipe  201  into the heating core  10  where water is heated into steam for application. However, the operation of this steam generator is to pump the water out of the water tank  20  by the water pump  30 . 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention has been accomplished to provide an innovative steam generator, which utilizes the known physical law to force a fluid out of a fluid storage tank into an electric heater for generating steam. It is the main object of the present invention to provide a steam generator, which is to have an electric heater, a fluid storage tank, a pressure valve and an air compression unit arranged together in such a manner that when an air pressure is given to the inside of the fluid storage tank by the air compression unit, a pressure is evenly distributed to the fluid in the fluid storage tank subject to Pascal&#39;s principle, forcing the fluid to flow into the inside of the electric heater where the fluid is heated into steam for application. Thus, the steam generator can deliver fluid from the fluid storage tank to the electric heater without using any water pump. Therefore, the steam generator is practical for home use and allows easy regulation of the amount of fluid and steam. 
         [0006]    To achieve this and other objects of the present invention, a steam generator comprises an electric heater for heating a fluid into steam, which comprises an electric heating member, a fluid inlet for guiding in a fluid to the electric heating member for heating into steam by the electric heating member and a first steam outlet for guiding out generated steam, a fluid storage tank, which comprises a fluid chamber holding a fluid, a fluid supply pipe arranged at a bottom side thereof and connected to the fluid inlet of the electric heater for guiding the fluid out of the fluid chamber into the electric heater for heating by the electric heating member, a pressure valve, which is mounted on the outside of the fluid storage tank and kept in communication with the fluid chamber for discharge of excessive air pressure out of the fluid storage tank, and an air compression unit, which is connected to the air inlet of the fluid storage tank and adapted for pumping air into the fluid chamber of the fluid storage tank to force the fluid out of the fluid chamber into the electric heater for heating into steam by the electric heating member. 
         [0007]    This, the steam generator enables the air compression unit to output air into the fluid storage tank, increasing the internal pressure of the fluid chamber of the fluid storage tank to force the fluid out of the fluid chamber into the electric heater for generating steam. Thus, the invention can deliver fluid without using any water pump. The steam generator of the invention is practical for home use, allowing easy regulation of the amount of fluid and steam. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a schematic drawing illustrating a steam generator according to the prior art. 
           [0009]      FIG. 2  is a schematic drawing illustrating a steam generator in accordance with a first embodiment of the present invention. 
           [0010]      FIG. 3  illustrates the operation of the air compression unit of the steam generator in accordance with the first embodiment of the present invention (I). 
           [0011]      FIG. 4  illustrates the operation of the air compression unit of the steam generator in accordance with the first embodiment of the present invention (II). 
           [0012]      FIG. 5  is a schematic drawing illustrating a steam generator in accordance with a second embodiment of the present invention. 
           [0013]      FIG. 6  is a schematic drawing illustrating a steam generator in accordance with a third embodiment of the present invention. 
           [0014]      FIG. 7  illustrates the operation of the air compression of the steam generator in accordance with the third embodiment of the present invention (I). 
           [0015]      FIG. 8  illustrates the operation of the air compression unit of the steam generator in accordance with the third embodiment of the present invention (II). 
           [0016]      FIG. 9  illustrates the operation of the air compression unit of the steam generator in accordance with the third embodiment of the present invention (III). 
           [0017]      FIG. 10  corresponds to  FIG. 2 , illustrating an air pressure regulating valve installed in the air intake pipe and a one-way valve installed in the fluid supply pipe. 
           [0018]      FIG. 11  corresponds to  FIG. 5 , illustrating an air pressure regulating valve installed in the air intake pipe and a one-way valve installed in the fluid supply pipe. 
           [0019]      FIG. 12  corresponds to  FIG. 6 , illustrating an air pressure regulating valve installed in the air intake pipe and a one-way valve installed in the fluid supply pipe. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    Referring to  FIG. 2 , a steam generator in accordance with a first embodiment of the present invention is shown comprising an electric heater  1 , a fluid storage tank  2 , a pressure valve  3  and an air compression unit  4 . 
         [0021]    The electric heater  1  comprises an outer shell  11 , an electric heating member  12  mounted in the outer shell  11 , a fluid inlet  13  connected to the outer shell  11  for guiding a fluid into the inside of the outer shell  11  for heating by the electric heating member  12  into steam, and a steam outlet  14  connected to the outer shell  11  for guiding generated steam out of the outer shell  11 . 
         [0022]    The fluid storage tank  2  is an enclosed container, having a fluid chamber  21  defined therein, a fluid supply pipe  22  extended from bottom side of the fluid chamber  21  and connected to the fluid inlet  13  of the electric heater  1  and an air inlet  23  located on the top side thereof in communication with the fluid chamber  21 . A fluid  7  is stored in the fluid chamber  21  for providing to the electric heater  1  for generating the desired steam. 
         [0023]    The pressure valve  3  is mounted on the outside of the fluid storage tank  2  in communication with the fluid chamber  21  for discharging excessive air pressure. The pressure valve  3  comprises a valve body  31 , a stopper  32  and a spring member  33 . The stopper  32  is supported on the spring member  33  inside the valve body  31  and movable in one specific direction for enabling the pressure valve  3  to discharge air. 
         [0024]    The air compression unit  4  is adapted to force out air. The air compression unit  4  can be a hand pump connected to the air inlet  23  of the fluid storage tank  2 . 
         [0025]    The air compression unit  4  can be operated to pump air into the fluid chamber  21  of the fluid storage tank  2  to impart a pressure evenly to the fluid  7  in the fluid chamber  21  subject to Pascal&#39;s principle, forcing the fluid  7  to flow through the fluid supply pipe  22  and the fluid inlet  13  into the inside of the outer shell  11  of the electric heater  1  where the fluid  7  is heated by the electric heating member  12  into steam for output through the steam outlet  14 . 
         [0026]    Referring to  FIGS. 3 and 4  and  FIG. 2  again, the air compression unit  4  comprises a housing  41  and a piston rod  42 . The housing  41  has an air outlet  411  located on its one end and connected to the air inlet  23  of the fluid storage tank  2 , and a piston hole  412  located on its other end for the passing of the piston rod  42 . The piston rod  42  has a piston  421  fixedly connected to its front end. The piston  421  fits the inside wall of the housing  41  and axially movable with the piston rod  42  relative to the housing  41  to pump air out of the housing  41  into the fluid chamber  21  of the fluid storage tank  2 . The air outlet  411  of the housing  41  may be directly connected to the air inlet  23  of the fluid storage tank  2 . Alternatively, as shown in  FIG. 2 , an air intake pipe  24  is connected between the air outlet  411  of the housing  41  and the air inlet  23  of the fluid storage tank  2 . When the user reciprocates the piston rod  42 , the piston  421  is moved back and forth in the housing  41  to pump air into the fluid chamber  21  of the fluid storage tank  2 , forcing the fluid  7  to flow to the inside of the electric heater  1 . 
         [0027]      FIG. 5  illustrates a steam generator in accordance with a second embodiment of the present invention. This second embodiment is substantially similar to the aforesaid first embodiment with the exception the structure of the air compression unit. According to this second embodiment, the air compression unit, referenced by  4   a , is electrically operated, comprising an air pump  41   a  and a drive  42   a  (for example, motor) adapted to move the air pump  41   a  in pumping air. The air pump  41   a  comprises an air outlet  411   a  connected to the air inlet  23  of the fluid storage tank  2 . The air outlet  411   a  of the air pump  41   a  may be directly connected to the air inlet  23  of the fluid storage tank  2 . Alternatively, an air intake pipe  24  is connected between the air outlet  411   a  of the air pump  41   a  and the air inlet  23  of the fluid storage tank  2 . When the drive  42   a  is started up, the air pump  41   a  is moved to pump air into the fluid chamber  21  of the fluid storage tank  2 , forcing the fluid  7  to flow to the inside of the electric heater  1 . 
         [0028]      FIGS. 6˜9  illustrate a steam generator in accordance with a third embodiment of the present invention. According to this third embodiment, the electric heater  1  further comprises a second steam outlet  15  located on the outer shell  11  and a steam pipe  16  extended from the second steam outlet  15  and connected to the air compression unit, referenced by  4   b . The air compression unit  4   b  is connected to the air inlet  23  of the fluid storage tank  2 . Thus, the steam generated by the electric heater  1  can drive the air compression unit  4   b  to pump air into the fluid chamber  21  of the fluid storage tank  2 . According to this third embodiment, the air compression unit, referenced by  4   b , comprises a housing  41   b  and a piston rod  42   b . The housing  41  comprises a partition plate  411   b  transversely arranged therein on the middle, a first chamber  412   b  and a second chamber  413   b  separated by the partition plate  411   b , a piston hole  414   b  cut through the partition plate  411   b  in communication between the first chamber  412   b  and the second chamber  413   b , an air inlet  415   b  located on one end of the housing  41   b  in communication with the first chamber  412   b  and connected to the steam pipe  16 , an air outlet  416   b  located on the other end of the housing  41   b  in communication with the second chamber  413   b  and connected to the air inlet  23  of the fluid storage tank  2 . The piston rod  42   b  is inserted through the piston hole  414   b , having a piston  421   b  fixedly connected to each of the two distal ends thereof. The two pistons  421   b  are respectively movably accommodated in the first chamber  412   b  and the second chamber  413   b.    
         [0029]    Thus, as shown in  FIG. 6 , the steam generated by the electric heater  1  flows out of the first steam outlet  14  and the second steam outlet  15 . The steam coming out of the second steam outlet  15  flows through the steam pipe  16  into the first chamber  412   b  to move the respective piston  421   b  in the first chamber  412   b , forcing the piston rod  42   b  toward the second chamber  413   b , and at the same time the piston  421   b  in the second chamber  413   b  pumps air out of the housing  42  through the air outlet  416   b  into the air inlet  23  of the fluid storage tank  2  to force the fluid  7  toward the electric heater  1 . This operation cycle is repeated again and again to supply the cold fluid  7  to the electric heater  1  automatically and continuously. 
         [0030]    Referring to  FIGS. 10˜12 , for allowing adjustment of the flow rate and speed of the supply of air from the air compression unit  4 ; 4   a ; 4   b  to the air inlet  23  of the fluid storage tank  2  to further control the internal pressure of the fluid chamber  21 , an air pressure regulating valve  5  may be used and installed in the air intake pipe  24 . The air pressure regulating valve  5  comprises a movable valve block  51 . Moving the valve block  51  in the air pressure regulating valve  5  relatively regulates the flow rate and speed of the supply of air from the air compression unit  4 ; 4   a ; 4   b  to the air inlet  23  of the fluid storage tank  2  to further control the internal pressure of the fluid chamber  21 , and therefore the flow rate and speed of the fluid  7  flowing from the fluid chamber  21  to the electric heater  1  is relatively controlled. Therefore the air pressure regulating valve  5  can control the amount and temperature of steam generated by the electric heater  1 . 
         [0031]    Referring to  FIGS. 2 ,  5  and  6  again, a one-way valve  6  is installed in the fluid supply pipe  22  of the fluid storage tank  2  for allowing flowing of the fluid  7  from the fluid chamber  21  to the electric heater  1  and prohibiting reverse flow of the fluid  7  from the electric heater  1  back to the fluid chamber  21 . The one-way valve  6  can be made in any of a variety of commercially available forms. Thus, when the air compression unit  4 ; 4   a ; 4   b  is stopped, the fluid  7  will not flow backwardly from the electric heater  1  to the fluid chamber  21 . The functioning of the one-way valve  6  can also prohibit flowing of the generated steam from the electric heater  1  to the fluid chamber  21 , assuring flowing of the generated steam out of the outer shell  11  through the first steam outlet  14  and the second steam outlet  15 . 
         [0032]    The design of the steam generator in accordance with the present invention enables the air compression unit  4 ; 4   a ; 4   b  to output air into the fluid storage tank  2 , increasing the internal pressure of the fluid chamber  21  of the fluid storage tank  2  to force the fluid  7  out of the fluid chamber  21  into the electric heater  1  for generating steam. Thus, the invention can deliver fluid without using any water pump. The steam generator of the invention is practical for home use, allowing easy regulation of the amount of fluid and steam. 
         [0033]    Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.