Abstract:
A drain ring adapted for use in a device for flushing a dead-end of an underground municipal water distribution system includes a pair of annular seals and a channel between the seals, an outlet passage extending from inside the ring to the channel, and a flapper adapted to close the outlet passage under the influence of at least one of pressure and flow. The drain ring is removably positioned between a shut-off valve and an outlet of the device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is related to U.S. Provisional Patent Application No. 61/081,601, filed Jul. 17, 2008, from which priority is claimed, and the disclosure of which is hereby incorporated by reference. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    This invention relates to hydrants or valves attached to municipal water systems, and in particular to a simple blow-off device for flushing portions of water systems. 
         [0004]    The need for periodically flushing portions of water systems, particularly dead-ends in the systems, has been recognized for many years, as shown for example in Lazenby III, U.S. Pat. No. 4,756,479. A summary of many of the problems requiring such flushing, as well as of the traditional solutions to those problems, is contained in my co-owned U.S. Pat. No. 5,201,338. More recently, such flushing operations have been automated, as described in McCarty, U.S. Pat. No. 5,921,270. The McCarty patent is owned by a company related to the assignee of the present invention. A similar approach is described in Newman, U.S. Pat. Nos. 6,035,704 and 6,358,408. Other approaches are shown in Poirer, U.S. Pat. No. 6,062,259, and Esmailzadeh, U.S. Pat. No. 6,467,498, and in Taylor et al, published applications US 20040252556, US 20040238458, US 20040238037, and US 20040238028. 
         [0005]    Although the prior art systems have met with success, the complexity of the systems, the time and effort required to install and use them, the difficulties attendant to removing and servicing them, and their consequent expense have limited their use. 
         [0006]    In some situations, the initial cost of the flushing system outweighs the cost of operating it. In these situations, a simple blow-off system comprising an underground manual valve is provided, and water is flushed through an above-ground discharge pipe. The discharge pipe is commonly a 2″ or 3″ diameter piece of plastic pipe, such as PVC, with an elbow at its free end. These systems are generally fabricated on-site. It is desirable to provide a drain in the discharge pipe below the frost line. The valves commonly used for such installations (for example, resilient seat gate valves), however, do not include an automatic drain. An example of a resilient seat gate valve is that disclosed in Bottenfield, U.S. Pat. No. 6,663,079. Without a drain, water remaining in the discharge pipe downstream of the manual valve is liable to freeze and damage the discharge pipe. If a drain hole is drilled into the discharge pipe below the frostline, it is open at all times, causing erosion of surrounding soil and possible contamination of the water supply. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    Briefly stated, one aspect of the present invention provides an automatic drain for a discharge pipe, the drain being designed to be removable from the pipe. The drain is preferably in the form of a ring having an annular channel between vertically spaced, generally horizontal o-rings. A passage between the interior of the ring and the annular channel is closed by a flapper shaped to be pushed closed by flowing water or line pressure when the manual valve is opened, but which is biased open against the pressure of water standing in the discharge pipe above it when the manual valve is closed. 
         [0008]    Another aspect of the invention provides a plastic discharge pipe with a provision for removably mounting an automatic drain device. 
         [0009]    Other aspects of the invention will be apparent to those skilled in the art in light of the following description of illustrative embodiments of the invention. It will be understood by those skilled in the art that many of the features and components of the foregoing patents and applications may be utilized in embodiments of the present invention. All the foregoing patents and applications are hereby incorporated by reference. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0010]    In the accompanying drawings which form part of the specification: 
           [0011]      FIG. 1  is a diagrammatic view in partial cross section, showing a flushing device in accordance with one embodiment of the present invention. 
           [0012]      FIG. 2  is a detail of a portion of the hydrant of  FIG. 1 , showing a drain ring in accordance with the invention seated in the hydrant while the hydrant is flushing. 
           [0013]      FIG. 3  is a top plan view of a drain ring of the device of  FIGS. 1-2 . 
           [0014]      FIG. 4  is a bottom plan view of the drain ring of  FIG. 3 . 
           [0015]      FIG. 5  is a sectional view taken along line  5 - 5  of  FIG. 3 . 
           [0016]      FIG. 6  is a view in side elevation of a tool for removing the drain ring of  FIGS. 3-5  from the flushing device of  FIGS. 1-2 . 
           [0017]      FIG. 7  is a view in perspective showing the tool of  FIG. 6  being utilized to engage the drain ring of  FIGS. 3-5 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0018]    The following detailed description illustrates the invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the invention, describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently believed to be the best mode of carrying out the invention. 
         [0019]    As shown in  FIG. 1 , an illustrative embodiment of the invention includes a blow-off flushing device  1  attached to an underground water main  3  through a shut-off valve  5 . Although the type of shut-off valve is immaterial to the present invention, the valve  5  is illustratively a ball valve having an upstream fitting adapted for the main  3 , and a downstream fitting adapted to receive a two-inch horizontal PVC pipe  7 , which may form a part of the blow-off  1 . The valve  5  is at the bottom of a valve box  9  with a cover  11  at or slightly above ground level  13 , as is well known in the art. 
         [0020]    The downstream end of the pipe  7  is attached by an elbow  15  to a vertical two-inch PVC stub pipe  17 . The stub pipe  17  has adhered to it a 2″×3″ reducer  19 . The reducer  19  is modified by removal of the usual shoulder, so as to allow the stub pipe  17  to extend through the reducer  19  so that the upper ends of the stub pipe  17  and the reducer  19  are aligned. The reducer  19  supports the lower end of a three-inch vertical pipe  21 , which is adhered to the reducer  19 . The three-inch vertical pipe  21  is preferably a schedule-40 PVC pipe cut to slightly over the depth of bury of the reducer  19 . A 0.375″ drain hole  23  (see  FIG. 2 ) is drilled in the three-inch pipe  21 , two inches from its bottom. This arrangement places the drain  23  about five inches above the axis of the horizontal pipe  7  and the top of the three-inch pipe  21  slightly above grade  13 . 
         [0021]    A threaded male hub  25  is adhered around the top of the vertical three-inch pipe  21  for mounting a threaded female socket  27  which carries 2″×3″ reducer  28  and a two-inch PVC pipe  29  having a ninety-degree elbow  31  at its upper end. The elbow  31  acts as the outlet for the blow-off  1  and protects it from debris. 
         [0022]    The elbow  15 , stub pipe  17 , and pipe  21 , at least to the depth of the drain hole  23 , are set in gravel. 
         [0023]    As shown in  FIGS. 2-5 , a drain ring  35  in accordance with the present invention sits on top of the stub pipe  17 . The drain ring  35  is made of any desired material, such as PVC or aluminum or stainless steel. It has an inner diameter equal to that of the two-inch stub pipe  17  and an outer diameter slightly smaller than the inner diameter of the three-inch pipe  21 . The drain ring  35  includes outer annular grooves  37  and  39  at the upper and lower ends of the ring, respectively, for holding o-rings  41  and  43 , respectively. The o-rings  41  and  43  form a snug, water-tight fit with the inside of the three-inch pipe  21 . Between the o-rings  41  and  43  is an annular channel  45 . A drain passage  47  extends from the inside of the drain ring  35  to the channel  45 . A flat  48  extends around the inner end of the drain passage  47  to allow a flapper  53  to close the inner end of the drain passage  47  as described hereinafter. An annular depression  49  at the inner end of the drain passage  47  forms a seat for an o-ring  51 . By way of illustration, the drain ring  35  may be 2.95″ in outer diameter and 2.00″ in inner diameter, with a height of 1.50″. The grooves  37  and  39  may be 0.283″ in height and 2.660 in diameter, and the channel  45  may be 0.5″ in height and 0.280 in diameter. The flat  48  may have a maximum depth of 0.093″ and a width of 0.8″. 
         [0024]    A flapper  53  is formed of 0.004″ spring  304  stainless steel, 0.5″ wide. The lower end of the flapper  53  is held to the bottom of the drain ring  35  by a screw  55 . The free upper end of the flapper  53  has an inturned ear  57 , illustratively bent at an angle of 45°. The lower end of the flapper  53  is bent at an angle of slightly greater than 90° so that the flapper  53  is spaced from the o-ring  51  sufficiently to allow water to drain through the passage  47  into the channel  45 . Two bolts  59  are partially threaded into the upper face of the drain ring  35  for removal of the drain ring as described hereinafter. 
         [0025]    In use, when the valve  5  is opened, conventionally by a valve wrench placed down valve box  9 , water flows from water distribution system  3  into supply pipe  7  and upwards through elbow  15 . Elbow  15  leads water upward into stub pipe  17  which perfectly aligns water to hit against spring flapper  53  and ear  57 , bending spring flapper  53  so that it mates with o-ring  51 , thereby closing drain hole  23 . O-rings  41  and  43  isolate water flow from cavity  45  and thereby isolate it from drain hole  23 . Should the outlet of the blow-off  1  be blocked, the pressure of water in the blow-off will also be sufficient to close the flapper  53 . 
         [0026]    When the valve  5  is closed, the flapper  53  has sufficient resilience to open against the pressure of water standing above it in the blow-off  1  and permits any water in the blow-off  1  to drain through the passage  47 , into channel  45 , and out the drain hole  23 . 
         [0027]    Should the drain ring  35  malfunction, it is easily removed by unscrewing the socket  27  from the hub  25 , and inserting a tool  61  into the three-inch pipe  21 . The tool  61  includes a handle  65 , a stem  67 , and a engagement plate  69  having slots  71 . The handle  65  is turned so that the slots  71  engage the bolts  59 , and the drain ring  35  is pulled out of the pipe  21 . The o-rings  41 ,  43 , and  51  and the flapper  53  are easily replaced as needed, and the drain ring  35  is pushed back through a chamfer in the hub  25  onto the top of the stub pipe  17  with the tool  61 . The rotational position of the drain ring  35  is not important. 
         [0028]    As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 
         [0029]    Numerous variations in the flushing device of the present invention will occur to those skilled in the art in view of the foregoing disclosure. 
         [0030]    Merely by way of illustration, a depression may be formed in the lower surface of the drain ring  35  for the screw  55  and the lower end of the flapper  53 , although it has been found that the drain ring&#39;s resting on the head of screw  55  does not interfere with the operation of the drain ring or the blow-off  1 . Alternatively, a depression for the screw  55  may be formed in the upper end of the stub pipe  17 , but this arrangement would require proper rotational alignment of the drain ring  35  by rotating it with the tool  61  until the screw head seated in the depression. Optionally, the flapper  53  may be held by a screw on the inside surface of the drain ring  35 . Other materials and sizes of parts may be used. Other valves  5  may be used, including automated valves activated by a timer, water conditions, or other inputs. A one-way (check) valve may be mounted in the drain hole  23  or the drain passage  47  to prevent backflow into the blow-off  1 . Multiple drain holes may be provided. Other arrangements for seating the drain ring  35  may be employed. 
         [0031]    These variations are merely illustrative. 
         [0032]    All of the patents and printed publications mentioned herein are hereby incorporated by reference.