Patent Publication Number: US-2012039022-A1

Title: Electrically Insulated Water Meter

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to water meters and in particular to a water meter electrically insulated from water pipes carrying water to and from the water meter. 
     Known water meters are connected to both waters mains and to building using standard metal couplings and associated metal water pipes, thereby providing a conducting path for electrical current. Such electric current (plumbing current) is often present in such water pipes as a result of grounding and wiring problems, or through ground current as the electricity makes its way back to the substation via the ground. Many homes today are now affected by plumbing current. For example, some of the current which would normally return through the electrical service line is instead channeled into the grounding system, where it returns to the transformer by way of alternate paths, including water pipes, the public water main and neighboring residences. Galvanic action may be an additional source of such electrical current. 
     Unfortunately, such plumbing current causes water mains and services to corrode and deteriorate thus shortening their life span and causing leaks and breaks. Electricity in the system is also a health risk for water company employees who tend to frequently be exposed to electrical shocks. No solutions are presently available to address this issues and a solution is needed. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention addresses the above and other needs by providing an electrically insulated water meter which prevents electrical current from flowing between in-house plumbing and a water main. Known water meters are connected to water mains and to in-house plumbing through metal couplings and metal pipes. The metal pipes, metal couplings, and a metal water meter housing complete an electrical circuit allowing the flow of electrical current. Such electrical current causes water mains and services to corrode and deteriorate thus shortening their life span by causing leaks and breaks, and is also a health risk for water company employees who risk electrical shocks due to the electrical current. The electrically insulated water meter includes non-conducting couplings between the water meter housing and the water pipes connected to the water meter housing, to prevent the flow of electrical current. Including the non-conducting couplings on both sides of the water meter housing prevents the electrical shocks to the water company employees. 
     In accordance with one aspect of the invention, there are provided electrically insulating couplings between a water meter housing and pipes connected to both a water main and in-house plumbing. 
     In accordance with another aspect of the invention, there is provided an electrically isolated water meter. The electrically isolated water meter includes a water meter housing made of an electrically conductive material, an electrically conductive first pipe in fluid communication with an inlet of the water meter housing, a first coupling connecting the first pipe to the water meter housing, an electrically conductive second pipe in fluid communication with an outlet of the water meter housing, and a second coupling connecting the second pipe to the water meter housing. At least one of the first coupling and the second coupling electrically isolate the water meter housing from the first pipe and the second pipe respectively, and preferably both the first coupling and the second coupling electrically isolate the water meter housing from the first pipe and the second pipe respectively. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: 
         FIG. 1A  is a side view of an electrically insulated water meter according to the present invention. 
         FIG. 1B  is a top view of the electrically insulated water meter according to the present invention. 
         FIG. 2  is a cross-sectional view of an electrically insulating coupling according to the present invention coupling a first pipe to the water meter taken along line  2 - 2  of  FIG. 1B . 
         FIG. 3A  is an end view of a nut element of the electrically insulating coupling according to the present invention. 
         FIG. 3B  is a side view of the nut element of the electrically insulating coupling according to the present invention. 
         FIG. 4  is a cross-sectional view of the nut element of the electrically insulating coupling according to the present invention taken along line  4 - 4  of  FIG. 3A . 
         FIG. 5  is an end view of a wash element of the electrically insulating coupling according to the present invention. 
         FIG. 6  is a cross-sectional view of the washer element of the electrically insulating coupling according to the present invention taken along line  6 - 6  of  FIG. 5 . 
     
    
    
     Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims. 
     A side view of an electrically insulated water meter  10  according to the present invention is shown in  FIG. 1A  and a top view of the electrically insulated water meter  10  is shown in  FIG. 1B . The water meters have a conductive housing  11  and plumbing current may be conducted from a first pipe  12 , through the conductive housing  11 , and to a second pipe  16 , if the pipes  12  and  16  are coupled to the housing  11  by conducting material. Such plumbing current causes water mains and services to corrode and deteriorate thus shortening their life span and causing leaks and breaks, and is also a health risk for water company employees who tend to frequently be exposed to electrical shocks. 
     A cross-sectional view of the electrically insulating coupling  14  according to the present invention, taken along line  2 - 2  of  FIG. 1B , is shown in  FIG. 2 . The couplings  14  include a nut  17  and a washer  18 . Both the nut  17  and the washer  18  are made from non-electrically conducting material. The non-electrically conducting couplings  14  electrically insulating the pipes  12  and  16  from the housing  11  thereby eliminating the plumbing current. 
     The nuts  17  include female threads  20  cooperating with male threads  15  on an inlet  11   a  and outlet  11   b  of the housing  11 . The pipes  12  and  16  include flairs, for example, a flair  12   a  on the pipe  12 , cooperating with flanges  17   a  on the nuts  17  to hold the pipes  12  and  16  to the housing  11 . The washers  18  separate the ends of the pipes  12  and  16  from the inlet  11   a  and outlet  11   b  of the housing  11 . 
     An end view of the nut  17  of the electrically insulating coupling  14  is shown in  FIG. 3A , side view of the nut  17  is shown in  FIG. 3A , and a cross-sectional view of the nut  17  taken along line  4 - 4  of  FIG. 3A  is shown in  FIG. 4 . The nut  14  includes a hexagonal outer shape  14   a  for cooperation with a tool for tightening the nut  14 , but may have any shape suitable for cooperation with a matching tool. 
     The washer  18  seats inside the nut  17  against the flange  17   a  in an area having a second inside diameter ID 2  and the pipes  12  and  16  enter the nut  17  through a passage having a first inside diameter ID 1 . An example of a suitable nut  17  has a length L of approximately 15/16 inches, a width W of approximately 1 and ⅞ inches, the first inside diameter ID 1  of approximately 1 and 1/16 inches, a second inside diameter ID 2  of approximately 1 and 5/16 inches, and a flange  17   a  having a thickness T of approximately ⅛ inches. 
     The above dimensions are one example. Water meters are made in various sizes depending on the water service provided, and the specifications of male threads on water meters are generally referred to as Water Meter Threads (WMT) and are commonly ¾ inch, one inch, 1 and ¼ inch, and 1 and ½ inch WMTs. Any water meter including electrically insulating couplings and having any thread size is intended to come within the scope of the present invention. 
     An end view of the washer  18  according to the present invention is shown in  FIG. 5  and a cross-sectional view of the washer  18  taken along line  6 - 6  of  FIG. 5  is shown in  FIG. 6 . The washer  18  has an outside diameter suitable for seating in the nut  17  against the flare  12   a  (see  FIG. 2 ) of the pipe  12  to separate the flair  12   a  from the end of the inlet  11   a  providing electrical insulation. 
     Known water meters are made by Badger, Neptune, Sensus and Rockwell, which are all compatible with the nut according to the present invention. While these are common water meters, any water meter installed to be electrically insulated from water pipes is intended to come within the scope of the present invention. 
     The coupling  14 , generally the nut  17  and washer  18 , must be made of an electrically insulating material with suitable mechanical properties to mechanically couple the pipes to the water meter, and the nut must additionally have sufficient mechanical strength to hold the pipes against the water meter housing. Examples of suitable materials for making the nut  17  include ABS, Styrene, Nylon, Polyester, Polycarbonate, Noryl, and Xenoy. The washer  18  is in compression and does not require the mechanical strength of the nut  17  but must also be an electrical insulator. An example of a suitable material for the washer is neoprene, rubber, leather or fiber. 
     While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.