Patent Publication Number: US-7216670-B1

Title: Drain apparatus with liquid trap and liquid level indicator

Description:
TECHNICAL FIELD 
     This invention relates to apparatus for draining liquid from a surface. The apparatus is so constructed as to form a liquid barrier preventing gases from passing upwardly therethrough. An indicator indicates when a liquid barrier or seal is formed thereby. 
     BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 5,192,156, issued Mar. 9, 1993, discloses apparatus for draining liquid from a surface into a sewer through a passageway extending between the surface and the sewer and for forming a liquid barrier between the sewer and the surface to prevent the flow of gases from a sewer to a surface. The apparatus incorporates structure which facilitates the flow of drainage liquid therethrough. 
     While the apparatus of U.S. Pat. No. 5,192,156 is highly effective, direct close visual inspection by an individual is required to determine whether or not sufficient liquid is in place in the apparatus to form a gas barrier. To determine whether such is the case, an inspector has to actually observe the interior of a conduit of the apparatus, either through holes in a grating at the top of the conduit or by removing the grating and directly viewing the conduit interior. 
     DISCLOSURE OF INVENTION 
     The present invention relates to an inexpensive, relatively simple approach enabling an observer to quickly and readily determine whether or not a liquid trap is formed in a liquid drain apparatus. This approach allows such determination to be made without close inspection having to be made. 
     The present invention encompasses a structural combination including liquid drain apparatus for draining liquid from a surface, the liquid drain apparatus including a conduit having an upper open end for receiving the liquid and a lower end. 
     A bottom wall partially extends across the lower end and defines an opening at the lower end for discharging liquid from the conduit. A partition having an upper partition end extends upwardly from the bottom wall and is cooperable with the conduit and the bottom wall to form an open topped trough within the conduit. 
     A baffle is located within the conduit and has a baffle lower distal end located in the trough above the bottom wall. The conduit, the baffle and the partition are operable to form a liquid seal to prevent gas from passing through the conduit when liquid in the trough is of sufficient depth to engage the baffle lower distal end. 
     A buoyant liquid level indicator device is disposed within the conduit and has an upper indicator device end and a lower indicator device end. The lower indicator device end is positioned in the trough. The buoyant liquid level indicator device is operable to float and move upwardly within the conduit only when a liquid seal is formed by the liquid drain apparatus. 
     Other features, advantages and objects of the present invention will become apparent with reference to the following description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a front, elevational view of a first embodiment of buoyant liquid level indicator device constructed in accordance with the teachings of the present invention; 
         FIG. 1B  is a side, elevational view of the indicator device of  FIG. 1A ; 
         FIG. 2A  is a front, elevational view of a second embodiment of buoyant liquid level indicator device; 
         FIG. 2B  is a side, elevational view of the liquid indicator device of  FIG. 2A ; 
         FIG. 2C  is a cross-sectional, side, elevational view of the indicator device of  FIG. 2A ; 
         FIG. 3  is a vertical, cross-sectional view of prior art liquid drain apparatus in place in the ground; 
         FIG. 4  is a view similar to  FIG. 3 , but illustrating a liquid level indicator device of the type shown in  FIGS. 1A and 1B , the liquid drain apparatus trap being empty; 
         FIG. 5  is a view similar to  FIG. 4 , but illustrating the liquid trap partially filled with liquid; 
         FIG. 6  is a view similar to  FIGS. 4 and 5 , but illustrating the liquid trap full and the buoyant liquid level indicator device floating and projecting from the top of the liquid drain apparatus to indicate that a liquid barrier preventing the escape of gas exists; 
         FIG. 7A  is a side, elevational view of a third embodiment of liquid level indicator device; 
         FIG. 7B  is a front, elevational view of the indicator device of  FIG. 7A ; and 
         FIG. 8  illustrates another configuration of liquid drain apparatus and illustrating a holder extending into the liquid drain apparatus slidably receiving a floating liquid level indicator device. 
     
    
    
     MODES FOR CARRYING OUT THE INVENTION 
     Referring now to  FIG. 3 , liquid drain apparatus of known construction is illustrated. More particularly, the drain apparatus is of the type shown in U.S. Pat. No. 5,192,156, issued Mar. 9, 1993. The apparatus  10  is for the purpose of draining liquid from a surface  12  to a sewer or other location. The liquid drain apparatus includes a conduit  14  having an upper open end  16  for receiving the liquid and a lower end. 
     A bottom wall  18  partially extends across the lower end and defines an opening  20  at the lower end for discharging liquid from the conduit. 
     A partition  22  having an upper partition end extends upwardly from the bottom wall and is cooperable with the conduit and the bottom wall to form an open topped trough  24  within the conduit. 
     A baffle  26  is disposed within the conduit and has a baffle lower distal end  28  located in the trough  24  above the bottom wall. 
     In  FIG. 3 , liquid  30  is in the trough and the conduit, the baffle and the partition are operable to form a liquid seal to prevent gas from passing through the conduit when liquid in the trough is, as shown, of sufficient depth to engage the baffle lower distal end. Reference may be had to U.S. Pat. No. 5,192,156 for additional details concerning drain apparatus  10 . 
     Referring now to  FIGS. 1A ,  1 B,  4 ,  5  and  6 , a form of buoyant liquid level indicator device constructed in accordance with the teachings of the present invention is illustrated and identified by reference numeral  40 . Device  40  includes an upper indicator device end  44  which may suitably be a strip of stiff plastic and a lower indicator device end which may suitably be a piece of cork  46  secured by adhesive or other means to strip  44 . 
     The buoyancy characteristics of the buoyant liquid level indicator device  40  are such that the device is operable to float and move upwardly within the conduit  14  when inserted therein only when a liquid seal is formed by the liquid drain apparatus. The liquid level indicator device  40  is elongated and the conduit  14  has a length longer than the length thereof. 
       FIGS. 4 ,  5  and  6  show the liquid indicator device in place within conduit  14  of apparatus  10 . The upper indicator device end  44  projects upwardly from the conduit upper open end when a liquid seal is formed by the liquid drain apparatus and is disposed below the conduit upper open end when a liquid seal is not formed by the liquid drain apparatus. 
       FIG. 4  shows the situation wherein the trough is empty, that is when the trough has no water therein and should be added. The liquid level indicator device engages bottom  18  and the top of the indicator device does not project above the apparatus  10 . 
       FIG. 5  shows the situation wherein the trough is partially filled with water but the water level is not yet sufficiently high to engage baffle distal end  28  to form a liquid trap. The buoyancy of the liquid level indicator device is such that it remains engaged with bottom wall  18 , again indicating to an observer that the trough should be filled. 
     After the level of liquid  30  in the trough is sufficiently high to form a liquid trap such as shown in  FIG. 6 , the liquid level indicator device will float upwardly and project beyond the upper end of the apparatus  10 , where it can readily be observed, even from a distance. 
     In  FIGS. 4 ,  5  and  6 , a grating  50  having drain slots  52  therein is positioned on the conduit. The liquid level indicator device projects through one of the slots  52  and the grating thus functions as guide structure for maintaining the liquid level indicator device in a substantially vertical orientation in the conduit. 
       FIG. 8  shows another form of liquid drain apparatus  10 A which has a diameter larger than apparatus  10 . In this arrangement, a holder  60  formed of wire or the like functions as a guide to maintain the liquid level indicator device in a substantially vertical orientation in the conduit while allowing the liquid level indicator device  40  to move up or down with the level of water  30 . 
       FIGS. 2A–2C  show another form of liquid level indicator device  40 A. As shown, liquid level indicator device  40 A is of integral construction, being suitably formed for example from molded plastic material. The lower end of the indicator device is in the form of a closed, hollow flotation chamber  62 . 
       FIGS. 7A and 7B  illustrate a liquid level indicator device  40 B which is wholly formed of buoyant material such as wood. The liquid level indicator device  40 B may be of integral construction, i.e. cut from one piece of wood, or be comprised of a plurality of parts glued or otherwise secured together.