Abstract:
A ground or earth connector comprises a metal tube having an integral connecting member. The earth connector is designed to be attached to a metal pipe, for example, a pipe in a central heating system, with the connecting member being deformable into permanent engagement with an earth cable so as to earth the metal pipe. The earth connector is tubular and is designed to be fitted between two adjacent pipe parts so as also to join the pipe parts together.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of Invention  
         [0002]     The present invention relates to improvements in grounding or “earthing” pipes. In particular, but not exclusively, the invention relates to earthing pipes in a central heating system of a building.  
         [0003]     2. Related Art  
         [0004]     At present, when installing a combination central heating boiler in a building, all piping to and from the boiler must be grounded or “earth bonded”, i.e. connected directly to the ground or earth cable of the electrical system, by law. It is not necessary that the pipes are connected to earth immediately adjacent the boiler, and often the pipes will be grounded or “earth bonded” away from the boiler, for example underneath a sink or wash basin.  
         [0005]     The known system of earth bonding the piping is to use an earth bonding clamp. A known earth bonding clamp is of a similar form to the so called Jubilee clip, with an additional screw and washer fastener to grip an electrical cable. Accordingly, the clamp is placed around the pipe and fastened, after which the cable is located between a plate and the washer in the screw fastener portion of the earth clamp. The screw fastener is screwed to increase the tension between the plate and the washer, thereby clamping the cable to the clamp, and hence against the pipe.  
         [0006]     The chosen location for the earth bonding clamp is often difficult to access, since the pipework of a building such as a home will necessarily largely be hidden from view. As above described, the earth bonding clamp will often be fitted beneath a sink or wash basin, and the space available to the fitter to manipulate the required tools is limited. In addition, the fitment of the earth bonding clamp is a two-handed job, and the fitter must ensure that the clamp is fitted in a position in which the cable can subsequently be located and held whilst the screw fastener is tightened. Accordingly, the fitment of such an earth bonding clamp is complicated and relatively time-consuming, the whole process taking about two minutes per clamp even for an experienced fitter. In a typical central heating system, six or more pipes go to and from the boiler, so that the time it takes to earth all of the pipes can be about twelve minutes or more.  
       SUMMARY OF THE INVENTION  
       [0007]     An aim of the invention is to provide an improved method of, and product for, grounding a pipe, also known as “earthing” a pipe.  
         [0008]     According to a first aspect of the invention there is provided a ground connector or “earth connector” comprising a tube for attachment to a metal pipe, the body having an integral connecting member, the connecting member being designed to be connected to a cable to earth a metal pipe. The connecting member being “integral” means that it is provided as a part of the earth connector and may be attached by solder or other fastening means to the body, or may be formed with the body in a single unit, for example, by molding or other forming techniques.  
         [0009]     The tube is preferably made of metal, although a tube not made of metal and defining a conductive path for the cable is envisaged.  
         [0010]     The connecting member is preferably blind to the metal body, in that the connecting member preferably is closed by the wall of the metal body to which it is connected.  
         [0011]     Preferably, the connecting member is conductive, for example copper, which allows compatibility with the predominant types of pipe in commercial use.  
         [0012]     The connecting member is preferably soldered to the metal body.  
         [0013]     The connecting member is preferably designed to connect to the cable by a clamping action of one or the other, most preferably the connecting member clamping the cable. Preferably, the connecting member has a cavity, most preferably the cavity is designed to receive an earth cable, most preferably the cavity approximately geometrically matches the cable. Preferably the connecting member is designed to be manually deformed by a hand tool such as pliers to clamp and securely grip an earth cable.  
         [0014]     The connecting member may have a recess in an outer wall thereof so as to allow better clamping of a cable. The connecting member may be in the form of a tube, the open end of the tube defining the recess.  
         [0015]     The metal tube may be pre soldered, in one form internally of the pipe or member. In a preferred embodiment recesses of the metal body house the solder, most preferably the recesses being one or more annulus.  
         [0016]     The metal tube may be designed to fit on a pipe having a diameter of between 6 mm and 200 mm for example, typically of copper type.  
         [0017]     The metal tube is open at both ends so as to allow it to be fitted between the ends of two lengths of pipework. The earth connector can therefore provide two functions of connecting two pipe lengths together and allowing the earth connection of the pipe. In the former respect, it is known that plumbers and pipe fitters will often interconnect two pipes close to a sink or wash basin and would previously use a short tubular connector for that purpose, the connector of the present invention fulfils that purpose and also fulfils the latter function also.  
         [0018]     According to a second aspect of the invention there is provided a kit of parts for grounding or earthing a metal pipe, the kit comprising a metal tube for attachment to a metal pipe and an earth cable, the metal tube having a connecting member integrally attached to it for connecting the metal tube to the cable, which in turn is connectable to earth.  
         [0019]     Preferably, the metal tube has pre-solder thereon or therein.  
         [0020]     According to a third aspect of the invention there is provided a (central) heating system having pipes into and out of a boiler, one or more of the pipes having an earth connector in accordance with the first aspect of the invention fitted thereto.  
         [0021]     Preferably, all of the pipes have an earth connector in accordance with the first aspect of the invention fitted thereto. Most preferably all of the pipes are earthed.  
         [0022]     According to a fourth aspect of the invention there is provided a method of grounding or earthing a metal pipe, comprising the steps of, providing an earth connector in accordance with the first aspect of the invention and connecting an earth cable thereto. Preferably, the metal pipe is part of a central heating system.  
         [0023]     Preferably, a cable is inserted into the connecting member. Most preferably, the connecting member is crimped into place over the cable.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]      FIG. 1  is a perspective view of an earth connector in accordance with a first embodiment of the invention,  
         [0025]      FIG. 2  is a perspective view of a cable for attachment to the earth connector of  FIG. 1 ,  
         [0026]      FIG. 3  is a side view of the cable fitted to the earth connector,  
         [0027]      FIG. 4  is a top view of the cable fitted to the earth connector,  
         [0028]      FIG. 5  is a front view of an earth connector fitted on a pipe network,  
         [0029]      FIG. 6  is a perspective view of an earth connector in accordance with a second embodiment of the invention, and  
         [0030]      FIG. 7  is a sectional view of the earth connector of  FIG. 6  showing internal details. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0031]     Referring to  FIG. 1 , the ground or earth connector comprises a tube  10  (in this embodiment of substantially circular cross-section), which has an outer surface  12 , on which a connecting member (in the form of a clamp  14 ) is attached. The clamp  14  is made of copper like the tube  10  but is of much smaller diameter than the tube and has a thinner external wall than the tube for the purpose to be explained below. The clamp  14  is fitted to the tube  10  by a permanent electrically conductive connection, e.g. by way of solder or the like  16 . The clamp  14  has an outer wall  18 . At one end of the clamp  14 , remote from the tube  10 , there is a recess  20 . Indeed, in the embodiment shown, the clamp  14  is in the form of a tube so in fact this recess  20  continues throughout the clamp  14  to the wall of the tube  10 .  
         [0032]     Referring to  FIG. 2 , an earth cable  24  is of conventional form, comprising copper wire(s) and having an insulating sheathing material  26  along most of its length, the insulating material having been removed at the end so as to expose the copper wires  28 .  
         [0033]     Referring to  FIG. 3 , to form the earth bond the exposed end  28  of the cable  24  is inserted in the cavity  20  of the clamp  14 . The clamp  14  is then pressed, e.g. by pliers, (or by another suitable clamping tool, for example a rotating crimper), to clamp the cable  24  in place and provide a permanent electrical connection between the clamp  14  and the cable  24 .  FIG. 3  shows that the outer wall  18  of the clamp  14  has a recess  22  formed by the clamping tool used to compress the wall  18  into engagement with the wires  28 . The clamp  14  can have a preformed deformation or deformations so as to provide a location for the clamping tool if desired, or can be marked to show the optimum position(s) for deforming the clamp, so as to facilitate the clamping operation.  
         [0034]     It will be noted from viewing  FIG. 3  that in this embodiment the cable  24  is attached to the metal body or tube  10  of the earth connector at an acute angle with respect to the tube longitudinal axis. This allows a greater surface area of the clamp  14  to be in contact with the tube  10  and thereby make the permanent connection between these components more reliable. Also, it is expected that the angled connection to the cable, in particular a downwardly-angled connection in use, will enable easier connection to the earth cable.  
         [0035]     It should also be noted, by referring to  FIG. 4 , that the cable  24  departs substantially radially from the tube  10 . This simplifies the construction of the clamp  14 , in particular the structure of the clamp where it engages the tube  10 . Also, the earth connector is substantially symmetrical about its centre-line (across the page as drawn in  FIG. 4 ), which is expected to allow the earth connector to be equally easy to use with the clamp  14  facing to the left or right, as desired by the fitter. Furthermore, with the restricted access typical of many locations in which the earth connector will be used, a central clamp connection such as that shown is expected to make it easier for the fitter to avoid obstructions both when fitting the tube  10  to the pipework and when subsequently fitting the cable  24  to the clamp  14 .  
         [0036]     Referring to  FIG. 5 , in use the earth connector (which in this embodiment comprises a tube  30  and clamp  32 , but could also comprise the tube  10  and the clamp  14 ), is fitted in line with two pipe parts  34  and  36 . The diameter of the pipes,  34  and  36 , is about 12½ mm. The pipe parts  34  and  36  are each fed (approximately midway) into the tube  30  and soldered in place. In another embodiment of the invention which is not shown for conciseness, the pipe diameter is about 25 mm. The tube  30  and pipe parts  34  and  36  cooperate to form a continuous pipe, leading to and/or from a boiler. It will be understood that a plumber or pipe fitter will typically connect a number of pipe parts  34 ,  36  etc. together between the boiler and a tap (for example), and the use of a short connecting piece to interconnect two pipe parts such as  34  and  36  is known. The present invention takes advantage of this fact by allowing replacement of the existing pipe connectors with earth connectors which fulfil the existing requirement and also provide the additional function of earth connection. It is therefore expected that when assembling the pipework from the boiler to a tap (for example) the plumber or pipe fitter will use an earth connector as described herein at the junction between two pipe parts at the chosen location for the earth bond, and will use existing pipe connectors at the other junctions between pipe parts.  
         [0037]      FIG. 5  shows a push-fit fitting in which the tube  30  can be pushed over the ends of the pipe parts  34  and  36 ; as in all other embodiments the tube could, however, be a compression fitting in which the ends of the tube are secured to the respective pipe parts by way of a rotatable nut.  
         [0038]      FIG. 6  shows another embodiment of the invention, in which an earth connector  46 , of tubular form, has two annular raised portions  48 ,  50  and a mid-point  51 .  FIG. 7 , which shows a cut away of the earth connector  46 , shows that inside the annular raised portion  48 ,  50  there is provided a ring of solder material  52 ,  54 . In use, pipe parts  56 ,  58  (shown in broken line) can be inserted into each end of the earth connector  46  until they engage the mid-point  51 . The in situ solder  52 ,  54 , which is of the same internal diameter as the tube  46 , can then be heated so as to solder and secure the pipe parts  56 ,  58  to the connector. Then, the clamp  60  can be connected to an earth cable  62 .  
         [0039]     It will be understood that in the embodiment of  FIG. 6  (as in all embodiments) the connector must make a fluid-tight seal with the pipe parts. Provided that the internal diameter of the tube ends closely match the external diameter of the pipe parts, a soldered connection will achieve the required seal and will also ensure good electrical conductivity between the earth connector and the pipe parts.  
         [0040]     It will be appreciated that using the grounding connectors/earth connectors and systems described hereinabove in accordance with the invention, makes forming a ground or earth bond quick and simple in comparison with the prior art method. Specifically, no screw fastening is required, and once the metal body is fitted to the pipework the earth connection can be made quickly and reliably by a simple clamping or crimping operation. Also, in the embodiments having a tubular metal body, fitment of the metal body to the pipework is no more time consuming than fitting an existing pipe connector, the metal body taking the place of the pipe connector.  
         [0041]     In the embodiments shown the ground/earth connector, and in particular those with tubular metal bodies, are linear (i.e. the two ends are parallel with each other), but it will be understood that this is not necessarily the case, and the body could comprise a corner or “dog-leg” in which the two ends are perpendicular or otherwise angled relative to one another, if required or desired.  
         [0042]     Although this invention has been described above with reference to particular means, materials and embodiments, it is to be understood that the invention is not limited to these disclosed particulars, but extends instead to all equivalents within the scope of the following claims.