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CROSS REFERENCES 
   This application is a United States national phase continuation application of co-pending international patent application number PCT/CN2006/003559, filed Dec. 22, 2006, which claims priority to Chinese patent application number 200520145320.2, filed Dec. 23, 2005, the disclosures of which are incorporated herein by reference. 

   TECHNICAL FIELD 
   This invention involves a drain system which prevents overflow by utilizing a magnetic device. 
   BACKGROUND 
   Traditional sinks have drains with manually operated stoppers. Some of these sinks have an additional, overflow hole near the upper edge of the sink to prevent accidental overflow. Some newer glass bowl sinks, other decorative sinks, and other traditional sinks do not have overflow holes. Neither the sink with drain only, nor the sink with drain plus overflow hole configuration is very reliable at preventing overflow. Sink overflows result in unnecessary and preventable waste and damage. 
   SUMMARY 
   A novel automatic drain and valve are disclosed herein, for use in conjunction with a manual drain valve on sinks with or without overflow holes. A typical manual drain valve allows waste water to pass from a sink to a drain pipe. According to the present disclosure, a bypass port is located above the manual drain valve poppet to allow the waste water to pass to the automatic valve when the manual drain valve is closed. The automatic valve is also connected to the drain pipe via an alternate drain path. The alternate drain path returns to the drain pipe below the manual valve, thus effecting a bypass around the closed manual drain. 
   Another aspect of the present invention is to provide an automatic drain device for a sink comprising a manual drain valve, which when closed, is operable to shut-off fluid drain to a drain pipe. The device also includes an automatic magnetic valve in fluid communication with the drain pipe and operable to automatically open a bypass drain path for overflow fluid from the sink to the drain pipe when the manual drain valve is closed. 
   A further aspect of the present invention is to provide a method to automatically drain a sink with an automatic drain comprising the steps of: closing a manual drain valve, allowing water to accumulate in the sink, and automatically opening a bypass drain path to the drain pipe when the water in the sink is at or above an overflow level. 
   Additional aspects will become more readily apparent from the detailed description and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Aspects and configurations of the disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify corresponding elements throughout. 
       FIG. 1  illustrates an automatic drain device according to an exemplary embodiment. 
       FIG. 2  illustrates the manual shutoff valve of  FIG. 1  in a closed position. 
       FIG. 3  illustrates the manual shutoff valve of  FIG. 1  in an open position. 
       FIG. 4  illustrates a perspective view of an automatic drain device in accordance with another embodiment. 
       FIG. 5  illustrates a perspective view of the automatic drain device of  FIG. 4  with a fitting for a breather hole exploded from the device housing. 
       FIG. 6  illustrates a perspective view of the automatic drain device of  FIG. 4  with a portion of an exterior device housing removed. 
       FIG. 7  illustrates a perspective view of the automatic drain device of  FIG. 4  with the exterior housing completely removed. 
       FIG. 8  illustrates an exploded perspective view of the automatic overflow valve portion of the automatic drain device of  FIG. 4   
       FIG. 9  illustrates a cross-sectional view of the automatic overflow valve portion of the automatic drain device of  FIG. 4  with the manual drain open. 
       FIG. 10  illustrates a cross-sectional view of the automatic overflow valve portion of the automatic drain device of  FIG. 4  with the manual drain closed and the fluid level in the sink at a safe level. 
       FIG. 11  illustrates a cross-sectional view of the automatic overflow valve portion of the automatic drain device of  FIG. 4  with the manual drain closed and the fluid level in the sink at an overflow level. 
       FIG. 12  illustrates the cross-sectional view of  FIG. 11  with an adjustment being made to overflow level. 
   

   DETAILED DESCRIPTION 
   As shown in  FIG. 1 , the automatic drain device includes a manual drain valve  1  and an automatic drain valve  5 , both connected to drain pipe  2 . Water, or fluid from sink  10  enters manual drain valve  1  and passes through to the drain pipe  2  if the manual drain valve  1  is open. 
   The manual drain valve  1  is further described with reference to  FIGS. 2 and 3 . The manual drain valve  1  can be the press-down type which is well-known in the industry. The manual drain valve  1  includes drain cover  18  which functions as a press-down button. The drain cover  18  is coupled to a valve stem  19  which is linked to lower body  17  via the stopper hinge  20 . The valve stem and lower body  17  are supported by support member  21  which is attached to a portion of drain pipe  2 . 
   The lower body  17  of the manual drain valve  1  can move relative to the valve stem  19 , but they are held apart by spring  15  which is coupled to the valve stem  19 . A poppet  13  is attached to the valve stem  19  between the drain cover  18  and the spring  15 . Poppet  13  closes the fluid path through the valve when it is held against the valve seat  12  by the stopper hinge  20 . 
   In one embodiment, the lower end of valve stem  19  has a groove  16  for containing one end of stopper hinge  20 . The other end of the stopper hinge  20  is connected to lower body  17 . Optionally, a magnet (not show in  FIG. 2  or  3 ) may be included on the back of groove  16  to attract the stopper hinge  20  and prevent it from slipping off. 
   As illustrated in  FIG. 2 , depression of drain cover  18  allows the stopper hinge  20  to latch in a closed position with the poppet  13  pressed into valve seat  12 . By slightly depressing the drain cover  18  again, the stopper hinge  20  releases the valve stem  19  upwards to an open position as illustrated in  FIG. 3 . In the open position, the poppet  13  is separated from the valve seat  12  allowing fluid to pass therebetween. The fluid then passes the support member  21  and flows down drain pipe  2 . 
   When the manual drain valve  1  is closed, the water or fluid in the sink can accumulate. If the water level in the sink begins to spill over the top of the sink an overflow level has been reached. An overflow level can be reached even in a sink with an overflow hole if the rate of inflow exceeds the rate of drainage through the overflow hole. When the water is maintained at a user-determined level that is below the top of the sink, the water or fluid is at a safety level. 
   The automatic drain disclosed herein can help maintain the water or fluid level in the sink at a safety level by connecting a bypass line  3  above the manual drain poppet  13 . Thus, when the manual drain valve  1  is closed, water will travel through the bypass line  3  towards automatic drain valve  5 . The bypass line  3  is connected to a lower body portion of the automatic drain valve  5 . The lower and upper body portions of the automatic drain valve  5  are separated by a float valve seat  11  with corresponding float stopper  4 , designed to seal against the float valve seat  11 . A return line  7  connects the upper body portion of the automatic drain valve  5  to the drain pipe  2  at a location beyond the manual drain valve  1 . 
   When the automatic drain valve  5  is empty, the float stopper  4  seals the drain by seating against the float valve seat  11 . The float stopper  4  is held against valve seat  11  by gravity and magnetism. As the float stopper  4  comprises at least some amount of ferrous material it has a weight and is attractable by a magnet force. In the automatic drain valve  5 , a float control magnet  6  is located opposite the float stopper  4  in the lower body portion. The float control magnet  6  is connected to a height adjustable overflow level slide  8 . The retaining force of the float stopper  4  against the float valve seat  11  can be changed by altering the distance between the float stopper  4  and the float control magnet  6 . As the distance between the float stopper  4  and the float control magnet  6  decreases by moving the overflow level slide  8  towards the float valve seat  11 , the retaining force is increased. 
   The float stopper  4  additionally includes enough material which is less dense than water to allow it to float. Thus, when the manual drain valve  1  is closed, the water in sink  10  begins to exert an upward pressure on the float stopper  4 . When the safety level is exceeded, the pressure of the fluid in the sink creates buoyancy pressure sufficient to overcome the gravity and magnetic force acting on the float stopper  4 . The float stopper  4  is lifted away from the float valve seat  11  and the water is then able to fill the upper body portion of the automatic drain valve  5  and exit through the return line  7  to the drain pipe  2 . An air inlet  9  may be provided at the top of the automatic drain valve  5  to allow the water to fully exit the return line  7  and the drain pipe  2  when both valves  1 , 5  are closed. 
   As the water level in the sink decreases, so does the buoyancy pressure it is able to exert on the float stopper  4 . Once the water level is at or below the safety level, the float control magnet  6  and gravity exert enough force on the float stopper  4  to overcome the buoyancy pressure and re-seat the float stopper  4  against the float valve seat  11 . Thus, the water level in the sink  10  may be adjusted by moving the overflow level slide  8  in and out. 
   The automatic drain works as follows: when the drain cover  18  is pressed down, overcoming the resistance of spring  15 , the poppet  13  and the valve stem  19  move downward relative to the valve lower body  17 . The stopper hinge  20  stops at an upper stopping point in groove  16 . The stopper hinge  20  moves within the upper stopping point and lower stopping point within groove  16 , and a magnet installed on the back of the groove  16  ensures the stopper hinge  20  does not fall off the groove  16 . Thus, the poppet  13  is pressed against the valve seat, shutting off flow to the drain pipe  2 . 
   If water continues to enter the sink, the water will enter into automatic drain valve  5  through the bypass line  3 . Initially, the water way will be shutoff due to the attraction by the float control magnet  6  on the float stopper  4 . 
   As water continues to enter the sink, the safety level is exceeded, resulting in a pressure sufficient to overcome the float control magnet  6 , lifting float stopper  4  away from the float valve seat  11 . Hence, the water is able to pass through the automatic drain valve  5  to the return line  7  and is drained through drain pipe  2 . 
   When the water level in sink  10  is reduced, and the water level is lowered to the safety level, the water pressure is reduced. Float control magnet  6  attracts the float stopper  4  back to the float valve seat  11 , stopping the water flow. When water is continuously added into the sink, the system works automatically. The water safety level in the sink  10  can be set and adjusted by using the overflow level slide  8 . 
   When the drain cover  18  is pressed again, poppet  13  and the valve stem  19  move upward with the spring  15  relative to lower valve body  17 . The stopper hinge  20  leaves an upper stopping point and returns to a lower stopping point, the poppet  13  separates from the valve seat  12 , and the water is drained through drain pipe  2 . 
     FIGS. 4 through 12  illustrate views of an automatic drain  100  in accordance with another exemplary embodiment. Referring to  FIG. 4 , the automatic drain  100  includes a manual drain valve  120  (shown in  FIG. 6 ) and an automatic drain valve  150  (shown in  FIG. 6 ), both housed within a valve sleeve  102 . The valve sleeve  102  is a tubular structure or sleeve having coupled to a top end thereof, mounting hardware  104  for placement or installation of a sink. The valve sleeve  102  is penetrated by air inlet fitting  110 . A drain flange  106  is included and is arranged to align with the drain outlet of the sink to permit water to drain therethrough. The drain flange  106  may be a ring that can be recessed in a drain seat of the sink. 
   The mounting hardware  104  and drain flange  106  have a through-hole aligned with a central (longitudinal) axis of the valve sleeve  102 . A shoulder  103  exists between the mounting hardware  104  and an upper end of the valve sleeve  102 . The drain cover  108  is shown above drain flange  106 . The drain cover  108  is intended to be placed in the sink to manually actuate the manual drain valve  120  and to provide a decorative cover for the drain hole. The operation of the drain cover  108  and the manual drain  120  are described above in conjunction with the first embodiment. 
   Turning now to  FIG. 5 , when the manual drain valve  120  is in a closed position attained by pressing down drain cover  108 , a small gap G exists between the bottom of the drain cover  108  and the top surface of the drain flange  106  to permit water to escape. When the manual drain valve  120  is in an open position attained by re-pressing drain cover  108 , the gap G is larger to permit the water to drain more rapidly. 
     FIG. 5  illustrates additional features of the air inlet fitting  110 . Air inlet fitting  110  is shown exploded from the valve sleeve  102 . The air inlet fitting  110  has threads  110   a  which mate with threads  122   a  of the manual drain valve  120 . Air inlet fitting  110  passes through aperture  112  before it is threaded to the manual drain valve  120 . 
     FIG. 6  illustrates a perspective view of the automatic drain  100  with a portion of a valve sleeve  102  removed showing the manual drain valve  120  stacked above the automatic drain valve  150 . As shown in  FIGS. 5 and 6 , aperture  112 , which is formed in the valve sleeve  102 , aligns with breather hole  122 . Breather hole  122  has female threads  122   a  which matingly receive threads  110   a  of air inlet fitting  110 . A grommet  124  is provided to seal breather hole  122  against water flowing between the valve sleeve  102  and the manual valve body  126 , and between the valve sleeve  102  and the automatic valve body  156 . 
   In general, valve bodies  126  and  156  are concentric with the valve sleeve  102 . The stacked valve bodies  126  and  156  serve as a primary drain pipe (as shown by flow line A in  FIG. 9 ). A gap or space is formed between the interior circumferential surface of the valve sleeve  102  and the exterior circumferential surface of valve bodies  126 ,  156  to permit overflow water to flow to the automatic drain valve  150 . 
   Turning now to  FIGS. 7 and 8 , the valve body  126  of the manual drain valve  120  and the valve body  156  of the automatic drain valve  150  are shown as tubular-shaped and generally hollow. The top end of valve body  126  has fixed thereto an upper coupling  130  to connect or affix to the mounting hardware  104 . The upper end of the valve body  126  also has at least one bypass port  132  formed therein. The bypass port  132  permits water rejected from the closed manual drain valve  120  to flow into the area between the valve sleeve  102  and the valve bodies  126 ,  156 . 
   The manual drain valve  120  further includes a valve seat  134  and poppet  136  mounted in valve body  126 . The valve seat  134  may be level with or below the lower end of the bypass port  132 . When the drain cover  108  is pressed down, the passage through the valve seat  134  is closed by poppet  136 . The addition of water will raise the level and amount of water in the sink. 
   As shown in  FIG. 8 , the valve body  156  of the automatic drain valve  150  includes a threaded top end  154  and a threaded bottom end  155 . The top end  154  is intended to receive an o-ring  164  or other sealing mechanism to couple and seal the connection of the top end  154  to a threaded bottom end of the manual valve body  126 . The valve body  156  further includes an inlet port  158  to receive the overflow water therein from the bypass port  132 . 
   The valve body  156  further includes a lower coupling  170 . The interior of the lower coupling  170  is threaded to mate and receive the threaded bottom end  155 . The connection is sealed with an o-ring  166  or other sealing mechanism. O-ring  164  is intended to be recessed in a corresponding groove (not shown) in the interior of the lower coupling  170 . The center of the lower coupling  170  is open to permit water to flow therethrough. The lower coupling  170  can connect to the plumbing system via threads  174  to transport drain water to a public utility system or septic system. 
   Turning briefly back to  FIG. 6 , the valve sleeve  102  (shown partially) is secured to the automatic drain  100  by fixing it between the upper coupling  130  and the lower coupling  170 . As shown in  FIG. 7 , an o-ring  162  seats in a groove (not shown) around the upper coupling  130 . Another o-ring  172  seats in a groove  168  around the lower coupling  170 . The two O-rings  162 ,  172  seal the space between the valve sleeve  102  and the manual and automatic valve bodies  126 ,  156 . 
   With specific reference to  FIG. 9 , a cross-sectional view of the automatic drain valve  150  is shown. The automatic valve body  156  transports water, represented by flow line A, from the manual valve body  126  when poppet  136  is open (as shown in  FIG. 7 ). Flow line B represents water transported from the bypass port  132  through inlet port  158 , also while poppet  136  is open. 
   The automatic drain valve  150  has a chamber  180  that has a float valve seat  182  at the upper end which is in communication with inlet port  158  to receive overflow water therethrough. Thus, the float valve seat  182  functions as an opening to pass water, and as a smooth surface against which float stopper  184  can seat. 
   Float stopper  184  in this embodiment is shaped generally like a rivet and is positioned above and in the upper opening of chamber  180 . Float stopper  184  is generally comprised of at least two materials divided into a float body  184   a  and a float magnetic area  190 A. However, it is possible to construct a float stopper of a single material. In the exemplary embodiment, the float body  184 A is made of a polymer, plastic or other waterproof and durable material. Float magnetic area  190 A comprises a magnet or ferrous material which is attracted to, or creates a magnetic force. 
   In  FIG. 9 , the automatic drain valve  150  is shown closed by float stopper  184  and float valve seat  182 . Hence, the water represented by flow line A flows between the chamber  180  and automatic valve body  156 . A float control magnet body  186  is located in the bottom of the chamber  180  and comprises a magnetic area  190 B, external threads  188   b  and adjustment means  195 . In the exemplary embodiment, the float control magnet body  186  is made of a polymer, plastic or other waterproof and durable material. Magnetic area  190 B comprises a magnet or ferrous material which is attracted to, or creates a magnetic force. 
   As shown in  FIG. 9 , the chamber  180  includes a plurality of threads  189  which mate with the threads  188   b  of the float control magnet body  186 . The mated threads  188   b ,  189  close the bottom of chamber  180 . The back of float control magnet body  186  has an adjustment means  195  which provides a means for moving the body  186  up or down in the chamber  180 . In the exemplary embodiment, the adjustment means  195  is a slot or means to receive a screw driver or other tool to turn or rotate the body  186  via the threads  188   b.    
   The distance from the magnetic area  190 B to the magnetic area  190 A determines the water safety level in the sink. Closing the distance, by raising  190 B, strengthens the magnetic force and allows a higher water level in the sink, while increasing the distance, by lowering  190 B, weakens the magnetic force and allows a lower water level in the sink. 
   As shown in  FIG. 10 , the manual drain valve  120  is closed and water in the sink is diverted through the inlet port  158 . This bypass flow is shown by flow line C. As shown in  FIG. 11 , if the level of water in the sink is above the safety level, the overflow water (shown by flow line D) exerts a buoyancy pressure sufficient to overcome the magnetic force between  190 A and  190 B, the water will lift the float stopper  184  away from the float valve seat  182 . Thus, water (shown by flow line E) will rise up through the chamber  180  and flow over the float valve seat  182 . The water flow E will then pass downward through the space between the inside of the automatic valve body  156  and the outside of the chamber  180 , into the drain pipe. 
   Once the level of water in the sink decreases below the safety level, the magnetic attraction between  190 A and  190 B will overcome the buoyancy pressure exerted by the overflow water and the float stopper  184  will re-seat against the float valve seat  182 . 
     FIG. 12  shoes an additional cross sectional view of the automatic drain  100   FIG. 11  with the adjustment means  195  which is operable by a screwdriver to extend the magnetic area  190 B upwards, thereby increasing the amount of water the sink will hold. 
   The float stopper is shown as a ball or a rivet-shape in the figures but the float stopper can have other shapes that are effective to stop the flow, such as, for example, wedge, conical, mushroom, tapered cylinder and the like. The float stopper may be comprised of a single or multiple materials which may include plastics, rubbers, foams, metals, metal-plastic composites, and other like durable and compliant materials. In addition, the float stopper may be attached to the automatic valve body by a hinge, tether, strap, or the like. The materials used to construct the valve bodies include metal, plastic or other sufficiently rigid materials. 
   The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Summary:
An automatic drain device for a sink and especially a sink without an overflow hole is provided. The device includes a magnetically controlled valve to open a return path for the flow of overflow fluid to the draining pipe. When the sink is about to overflow, water pressure increases causing the valve in the magnetically controlled valve to open a bypass path to the drain.