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CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of the PCT Application No. PCT/GB2015/050219 filed on Jan. 30, 2015, which claims priority to and the benefit of GB Application No. 1401557.2, filed on Jan. 30, 2014, and further claims the priority to and the benefit of GB Application No. 1513876.1, filed Aug. 5, 2015 and GB Application No. 1522290.4, filed Dec. 17, 2015, and the disclosures of each of the applications above is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
     Field of the Invention 
       [0002]    The present invention relates to a plumbing device which allows a pressure and/or temperature relief valve for a fresh water system to be connected to a waste pipe or soil stack without the risk of back contamination or odours. 
         [0003]    An example of the use of a relief valve is with an unvented domestic hot water storage system (UVHWSS) or unvented hot water heater (UVHWH). Such a system typically has a temperature and/or pressure relief valve connected to a discharge pipe. The regulations for connection of the discharge pipe to a waste water system are strict because of the risk of back contamination from the pathogenic water in the waste water system to the fresh water in the storage system. Typically, the regulations require a tundish to provide a visible point of discharge and an air gap (to provide backflow prevention) and the outflow from the tundish to be connected in a particular way to discharge above an external ground floor gulley. Such a connection requires careful engineering and is expensive to install. 
         [0004]    In order to connect the vent valve to a soil stack within a building, arrangements need to be made to provide an odour trap to prevent any foul gases from the soil stack from entering the domestic location. On most domestic installations, a water trap would be used to prevent escape of gases and odours from the soil stack. Typically, a water trap comprises a bended tube in which water is trapped. A water trap allows passage of liquid and suspended solids but not gases. Generally speaking, a water trap is not suitable for use with a tundish as it will become ineffective through drying out. A water trap is also relatively bulky and is not suitable for use in all locations. 
         [0005]    More recently, a product has been approved which provides an odour trap which allows the discharge pipe to be connected to a soil stack within a building. This product is designed to be used in association with a tundish and is not easy to use with an UVHWH because of its overall length. 
         [0006]    A way of ameliorating these problems has been sought. 
       SUMMARY 
       [0007]    According to the invention, there is provided a connector which connector comprises a chamber having an open upper chamber and a lower closable chamber, an inlet connector, an outlet connector formed in a floor of the lower chamber wherein the inlet connector is supported above the open upper chamber by one or more arms and wherein the lower chamber is closable by a non-return valve which is arranged to open at a pre-selected pressure. 
         [0008]    In some embodiments, the pre-selected pressure is a pressure applied by a flow of liquid from the inlet such as may be produced by a pressure and/or temperature relief valve in operation. For example, the pre-selected pressure may be sufficiently high to prevent accidental opening of the non-return valve (for example due to dust or condensation on the valve) but not so high to restrict flow of liquid from the inlet such that liquid overflows from the open upper chamber. A skilled person would be able to determine a suitable pressure. 
         [0009]    In some embodiments, the chamber has a tubular middle chamber arranged between the upper chamber and the closable lower chamber. In some embodiments, the pre-selected pressure is no more than the pressure from a volume of liquid which can fill the tubular middle chamber. The advantages of the middle chamber include that it reduces the risk of accidental opening of the non-return valve by providing a receptacle for collection of liquid; and that the presence of a non-return valve in a tundish does not interfere with the operation of the tundish because the risk of spillage of liquid from the tundish is reduced. 
         [0010]    In some embodiments, the valve may be a non-return valve, for example a diaphragm check valve, a lift valve or a duck bill valve. 
         [0011]    In some embodiments, the valve is a lift valve having a valve stem. In some embodiments, the upper chamber provides one or more ribs to support a valve guide for the valve stem. In some embodiments, the lift valve has a resilient member to bias it into a closed position. In some embodiments, the resilient member is arranged on the lift valve above the valve guide. Provision of a resilient member above the valve guide has the advantage of enabling the valve stem to be self-guiding such that only one valve guide is required. 
         [0012]    In some embodiments, the chamber may be provided as a unitary component or single piece. Any or any, any combination or all of the open upper chamber, lower closable chamber, inlet connector, outlet connector and/or one or more arms may be unitarily formed or joined/fused, for example in a manner that prevents separation without breaking the chamber. 
         [0013]    According to aspects of the invention, there is provided a shielded connector which comprises a shield and a connector which comprises: a chamber having an open upper chamber and a lower chamber, an inlet connector and an outlet connector formed in a floor of the lower chamber, wherein the inlet connector is supported above the open upper chamber by one or more arms; wherein the upper chamber has an upper chamber floor having an upper chamber outlet, the upper chamber is in fluid communication with the lower chamber by means of the upper chamber outlet; wherein the upper chamber outlet has a non-return valve which is arranged to open at a pre-selected pressure; wherein the lower chamber forms a flow conduit for receiving the valve when it is open; and wherein the shield is shaped to cover the open upper chamber. 
         [0014]    According to aspects of the invention, there is also provided a connector which comprises: a chamber having an open upper chamber and a lower chamber, an inlet connector and an outlet connector formed in a floor of the lower chamber, wherein the inlet connector is supported above the open upper chamber by one or more arms; wherein the upper chamber has an upper chamber floor having an upper chamber outlet, the upper chamber is in fluid communication with the lower chamber by means of the upper chamber outlet; wherein the upper chamber outlet has a non-return valve which is arranged to open at a pre-selected pressure; wherein the lower chamber forms a flow conduit for receiving the valve when it is open. 
         [0015]    According to aspects of the invention, there is further provided a shield for a connector having an open upper chamber wherein the shield is shaped to cover the open upper chamber. 
         [0016]    According to aspects of the invention, there is also provided a valve assembly for use in sealing an outlet in a connector according to the invention wherein the valve assembly comprises a stem, a biasing member for biasing the valve assembly into a closed position, a valve disc for sealing the outlet, an upper washer and a lower washer wherein the upper and/or lower washer is shaped to support the valve disc such that the valve disc is not distorted in use. In some embodiments, the valve assembly additionally comprises an additional upper washer to provide extra support. 
         [0017]    In some embodiments, the upper and/or lower washers of the valve assembly are shaped to support the valve disc such that the valve disc is not compressed in use. It has been found that without the shaped upper and/or lower washer, the valve disc can distort such that the amount of water required to open the valve may change. In some embodiments, the upper and lower washers and the valve disc form central apertures for mounting on the valve stem; wherein one of the upper and lower washers forms a projection around its central aperture and wherein the valve disc aperture is shaped to receive the projection such that valve disc is supported by the upper and lower washers. 
         [0018]    The advantages of a connector according to the invention may include that as it is an adapted tundish, it may be compact and space saving such that it can be used in a restricted location such as with an under counter water heater. Its simple construction may enable it to have a rating for temperatures up to 100° C. Furthermore, by providing the lower chamber with a flow conduit for receiving the opened valve, the connector may offer an improved flow rate. 
         [0019]    Further advantages may include that the shield may allow the connector to be used to vent a domestic boiler pressure relief valve to a waste water drain by preventing a user from inserting their fingers into the open upper chamber when the connector is in use. This is because the connector needs to be mounted on an outlet from the boiler which is visible but when it is in use, very hot water will be passed through the connector. Therefore the shield can provide protection for a user from that water. 
         [0020]    In some embodiments, the shield has a window such that water flow through the upper chamber can be observed. In some embodiments, the shield may be formed partly or wholly from a transparent material. 
         [0021]    In some embodiments, the shield has a loose fit on the upper chamber such that the connector provides a vent to atmospheric pressure. In some embodiments, the shield has a tolerance fit (for example, a water tight fit) to the upper chamber wherein the shield has an outlet which provides the shielded connector with a vent to atmospheric pressure. In some embodiments, the connector and/or shield may have a rubber seal to minimise water spillage where the shield fits to the upper chamber. 
         [0022]    In some embodiments, the flow conduit is formed by a wall which is spaced from the valve in use so as to provide a volume for liquid flow. In some embodiments, the flow conduit allows the valve to open sufficiently to allow a high flow of water. In some embodiments, a high flow rate of water is a flow rate of over 12 litres per minute, for example a flow rate of from 12 litres per minute, optionally from 15 litres per minute, optionally from 18 litres per minute to 30 litres per minute, optionally to 25 litres per minute, optionally to 18 litres per minute. In some embodiments, the connector according to the invention is suitable for use in venting an unvented boiler or cylinder, particularly a cylinder having high discharge characteristics such as a Megaflo (registered trademark) unvented cylinder or modern design unvented boilers. 
         [0023]    some embodiments, the lower chamber forms a first portion and the flow conduit wherein the first portion accommodates the upper chamber outlet and the valve when it is closed. In some embodiments, the first portion has a diameter which is greater than the diameter of the flow conduit such that there is a step between the first portion and the flow conduit. In some embodiments, the first portion has a diameter which is the same as the diameter of the flow conduit. In some embodiments, the floor of the lower chamber is a shelving floor. In some embodiments, the lower chamber floor is arranged between the flow conduit and the outlet connector. 
         [0024]    In some embodiments, the pre-selected pressure is a pressure applied by a flow of liquid from the inlet such as may be produced by a pressure and/or temperature relief valve in operation. For example, the pre-selected pressure may be sufficiently high to prevent accidental opening of the non-return valve (for example due to dust or condensation on the valve) but not so high to restrict flow of liquid from the inlet such that liquid overflows from the open upper chamber. A skilled person would be able to determine a suitable pressure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The invention will now be illustrated with reference to the following Figures of the accompanying drawings which are not intended to limit the scope of the invention claimed: 
           [0026]      FIG. 1  shows a schematic vertical cross-sectional view of a first embodiment of the invention; 
           [0027]      FIG. 2  shows a schematic overhead plan view of the first embodiment of the invention; 
           [0028]      FIG. 3  shows a schematic horizontal cross-sectional view of the first embodiment of the invention taken along line marked A-A′ on  FIG. 1 ; 
           [0029]      FIG. 4  shows a schematic vertical cross-sectional view of a second embodiment of the invention; 
           [0030]      FIG. 5  shows a schematic overhead plan view of the second embodiment of the invention; 
           [0031]      FIG. 6  shows a schematic vertical cross-sectional view of a third embodiment of the invention; 
           [0032]      FIG. 7  shows a schematic overhead plan view of the second embodiment of the invention 
           [0033]      FIG. 8  shows a schematic vertical cross-sectional view of a third embodiment of the invention; 
           [0034]      FIG. 9  shows a schematic vertical cross-sectional view of a further embodiment of the invention; 
           [0035]      FIG. 10  shows a schematic vertical cross-sectional view of a further embodiment of the shielded connector according to the invention; 
           [0036]      FIG. 11  shows a schematic horizontal cross-sectional view of the embodiment of the invention taken along line marked B-B′ on  FIG. 10 ; 
           [0037]      FIG. 12  shows a cross-sectional view of a shield according to the invention; 
           [0038]      FIG. 13  shows a schematic perspective view of the parts from which a shielded connector according to an example of the invention may be constructed; and 
           [0039]      FIG. 14  shows a schematic perspective view of a valve assembly for use in the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0040]    A first embodiment of a connector according to the invention indicated generally at  100  is shown in  FIGS. 1, 2 and 3 . Connector  100  has an inlet  105 , an upper chamber  162 , a middle chamber  177 , a lower chamber  182  and a lift valve indicated at  142 . 
         [0041]    Inlet  105  is supported above upper chamber  162  by a pair of diametrically opposed arms  125  such that a vertical gap  107  is formed between the inlet and the upper chamber  162 . Inlet  105  has an outer thread  110  for engaging with a tap connector (or other pipe fitting) and forms a tapered beak drip  115  which projects downwards into the vertical gap  107 . Arms  125  are arranged so that the vertical gap  107  is of a height sufficient to provide an air gap of type AA which is typically at least about 20 mm. 
         [0042]    Upper chamber  162  is shaped by circumferential upper chamber wall  165  and a shelving upper chamber floor  170 . Upper chamber  162  has an open mouth for receiving liquid from the inlet. The upper chamber wall  165  supports arms  125 . Upper chamber floor  170  forms upper chamber floor opening  175  which is the opening to tubular middle chamber  177  such that upper chamber floor  170  has an inverted truncated conical shape and such that the upper chamber floor  170  has a funnel shape for directing liquid to the upper chamber floor opening  175 . Upper chamber wall  165  has three inwardly projecting ribs  130  which support valve guide  135  which is arranged in the centre of the opening to upper chamber  162 . 
         [0043]    The lift valve  142  has the following components: a valve stem  140 , a valve disc  145 , a valve disc fixing  150 , a valve spring  155  and a valve spring clip  160 . The valve stem  140  is arranged to run through valve guide  135 . At an upper part of the valve stem  140  above the valve guide  135 , valve spring  155  is arranged on the valve stem  140  and secured to an upper end of the valve stem  140  by valve spring clip  160 . At a lower end of the valve stem  140 , the valve disc  145  is secured by valve disc fixing  150 . Valve disc  145  is formed from a resilient material such as a plastics or rubber material, for example EPDM rubber. In an alternative embodiment, the valve spring  155  may be replaced by a suitable resilient member as would be known to a person of skill in the art. 
         [0044]    The tubular middle chamber  177  has a lower opening which forms a valve seat for lift valve  142  and which lower opening is normally closed by valve disc  145  which is biased by the valve spring  155  into that position. The valve spring  155  is arranged to open the lift valve  142  at a pre-selected pressure on the valve disc  145 . A suitable pre-selected pressure may be that determined by when the tubular middle chamber  177  is full of liquid. 
         [0045]    The lower chamber  182  has a ceiling  170 , 177 , a tubular lower chamber wall  180  and a shelving lower chamber floor  185 . The ceiling  170 , 177  of the lower chamber  182  is formed by the upper chamber floor  170  and middle chamber  177  and forms an opening which is normally closed by valve  142 . Lower chamber floor  185  shelves to form an opening for outlet  120  such that lower chamber floor  185  has an inverted truncated conical shape and such that the lower chamber floor  185  has a funnel shape for directing liquid to outlet  120 . Outlet  120  has a tubular shape and has an outer thread  110  for engaging with a tap connector (or other pipe fitting). 
         [0046]    In an alternative embodiment, the diameter of valve disc  145  may be less than that for outlet  120  such that the valve spring  155  and/or valve disc  145  may be replaced by removing valve spring clip  160 , allowing the lift valve  142  to drop through outlet  120  and out of the connector  100  so that one or more of the components of lift valve  142  may be replaced. 
         [0047]    The connector in any example of the invention may be formed such that the rigid connector body, i.e. excluding the moveable valve components, may be provided as a single piece. The connector body may be formed as a walled structure by moulding. The connector body may be formed as a plurality of sections fused together to provide a single piece. For example, ultrasonic welding or the like may be used to fuse the parts together as a single piece. 
         [0048]    A second embodiment of a connector according to the invention indicated generally at  200  is shown in  FIGS. 4 and 5 . Connector  200  has an inlet  205 , an upper chamber  262 , a middle chamber  277 , a lower chamber  282  and a diaphragm check valve  290 . The numbering of the reference numerals for features of the second embodiment corresponds to that for like features of the first embodiment. 
         [0049]    Inlet  205  is supported above upper chamber  262  by a pair of diametrically opposed arms  225  such that a vertical gap  207  is formed between the inlet and the upper chamber  262 . Inlet  205  has an outer thread  210  for engaging with a tap connector (or other pipe fitting) and forms a tapered beak drip  215  which projects downwards into the vertical gap  207 . Arms  225  are arranged so that the vertical gap  207  is of a height sufficient to provide an air gap of type AA which is typically at least about 20 mm. 
         [0050]    Upper chamber  262  is shaped by circumferential upper chamber wall  265  and a shelving upper chamber floor  270 . Upper chamber  262  has an open mouth for receiving liquid from the inlet. The upper chamber wall  265  supports arms  225 . Upper chamber floor  270  forms upper chamber floor opening  275  which is the opening to tubular middle chamber  277  such that upper chamber floor  270  has an inverted truncated conical shape and such that the upper chamber floor  270  has a funnel shape for directing liquid to the upper chamber floor opening  275 . The features of the upper part of connector  200  are shown in the overhead plan view depicted in  FIG. 5 . 
         [0051]    Diaphragm check valve  290  is formed from a resilient material and is shaped to be biased into a closed position. Diaphragm check valve  290  is shown in an open position by a partially occluded form shown on  FIG. 4 . The tubular middle chamber  277  has a lower opening which forms a valve seat for lift valve  142  and which lower opening is normally closed by the diaphragm check valve  290 . The diaphragm check valve  290  is attached the lower opening of middle chamber  277 . The diaphragm check valve  290  is arranged to open at a pre-selected pressure. A suitable pre-selected pressure may be that determined by when the tubular middle chamber  277  is full of liquid. 
         [0052]    The lower chamber  282  has a ceiling  270 , 277 , a tubular lower chamber wall  280  and a shelving lower chamber floor  285 . The ceiling  270 , 277  of the lower chamber  282  is formed by the upper chamber floor  270  and middle chamber  277  and forms an opening which is normally closed by diaphragm check valve  290 . Lower chamber floor  285  shelves to form an opening for outlet  220  such that lower chamber floor  285  has an inverted truncated conical shape and such that the lower chamber floor  285  has a funnel shape for directing liquid to outlet  220 . Outlet  220  has a tubular shape and has an outer thread  210  for engaging with a tap connector (or other pipe fitting). 
         [0053]    A third embodiment of a connector according to the invention indicated generally at  300  is shown in  FIG. 6 . Connector  300  has an inlet  305 , an upper chamber  362 , a middle chamber  377 , a lower chamber  382  and a duck bill valve  395 . The numbering of the reference numerals for features of the third embodiment corresponds to that for like features of the first and second embodiments. 
         [0054]    Inlet  305  is supported above upper chamber  362  by a pair of diametrically opposed arms  325  such that a vertical gap  307  is formed between the inlet and the upper chamber  362 . Inlet  305  has an outer thread  310  for engaging with a tap connector (or other pipe fitting) and forms a tapered beak drip  315  which projects downwards into the vertical gap  307 . Arms  325  are arranged so that the vertical gap  307  is of a height sufficient to provide an air gap of type AA which is typically at least about 20 mm. 
         [0055]    Upper chamber  362  is shaped by circumferential upper chamber wall  365  and a shelving upper chamber floor  370 . Upper chamber  362  has an open mouth for receiving liquid from the inlet. The upper chamber wall  365  supports arms  325 . Upper chamber floor  370  forms upper chamber floor opening  375  which is the opening to tubular middle chamber  377  such that upper chamber floor  370  has an inverted truncated conical shape and such that the upper chamber floor  370  has a funnel shape for directing liquid to the upper chamber floor opening  375 . The features of the upper part of connector  200  are shown in the overhead plan view depicted in  FIG. 7 . 
         [0056]    Duck bill valve  395  is formed from a resilient material biased to a closed position. Duck bill valve  395  is shown in an open position by the partially occluded form shown on  FIG. 6 . Duck bill valve comprises two downwardly extending, opposed flexible impervious wall members of complementary shapes disposed face to face in surface contact so that there is no through passage between them in their normal state and where they are resiliently urged into the normal state. 
         [0057]    The tubular middle chamber  377  has a lower opening on which the wall members of the duck bill valve  395  are mounted and which lower opening is normally closed by the duck bill valve  395 . Liquid at a pre-selected pressure will force the wall members of the duck bill valve  395  apart to permit flow between them from the middle chamber  377  into the lower chamber  382 . A suitable pre-selected pressure may be that determined by when the tubular middle chamber  377  is full of liquid. The duck bill valve  395  prevents liquid flow in the opposite direction by the close surface contact between its wall members. 
         [0058]    The lower chamber  382  has a ceiling  370 , 377 , a tubular lower chamber wall  380  and a shelving lower chamber floor  385 . The ceiling  370 , 377  of the lower chamber  382  is formed by the upper chamber floor  370  and middle chamber  377  and forms an opening which is normally closed by diaphragm check valve  390 . Lower chamber floor  385  shelves to form an opening for outlet  320  such that lower chamber floor  385  has an inverted truncated conical shape and such that the lower chamber floor  385  has a funnel shape for directing liquid to outlet  320 . Outlet  320  has a tubular shape and has an outer thread  310  for engaging with a tap connector (or other pipe fitting). 
         [0059]    A fourth embodiment of a connector according to the invention indicated generally at  400  is shown in  FIG. 8 . Connector  400  has an inlet  405 , an upper chamber  462 , a middle chamber  477 , a lower chamber  482  and a lift valve indicated at  442 . 
         [0060]    Inlet  405  is supported above upper chamber  462  by a pair of diametrically opposed arms  425  such that a vertical gap  407  is formed between the inlet and the upper chamber  462 . Inlet  405  has an outer thread  410  for engaging with a tap connector (or other pipe fitting) and forms a tapered beak drip  415  which projects downwards into the vertical gap  407 . Arms  425  are arranged so that the vertical gap  407  is of a height sufficient to provide an air gap of type AA which is typically at least about 20 mm. 
         [0061]    Upper chamber  462  is shaped by circumferential upper chamber wall  465  and a shelving upper chamber floor  470 . Upper chamber  462  has an open mouth for receiving liquid from the inlet. The upper chamber wall  465  supports arms  425 . Upper chamber floor  470  forms upper chamber floor opening  475  which is the opening to tubular middle chamber  477  such that upper chamber floor  470  has an inverted truncated conical shape and such that the upper chamber floor  470  has a funnel shape for directing liquid to the upper chamber floor opening  475 . Upper chamber wall  465  has three inwardly projecting ribs  430 A which support valve guide  435 A which is arranged in the centre of the opening to upper chamber  462 . 
         [0062]    The lower chamber  482  has a ceiling  470 , 477 , a tubular lower chamber wall  480  and a shelving lower chamber floor  485 . The ceiling  470 , 477  of the lower chamber  482  is formed by the upper chamber floor  470  and middle chamber  477  and forms an opening which is normally closed by valve  442 . Lower chamber floor  485  shelves to form an opening for outlet  420  such that lower chamber floor  485  has an inverted truncated conical shape and such that the lower chamber floor  485  has a funnel shape for directing liquid to outlet  420 . Outlet  420  has a tubular shape and has an outer thread  410  for engaging with a tap connector (or other pipe fitting). Lower chamber wall  480  has three inwardly projecting ribs  430 B which support valve guide  435 B which is arranged in the centre of lower chamber  482 . 
         [0063]    The lift valve  442  has the following components: a valve stem  440 , a valve disc  445 , a valve disc fixing  450 , a valve spring  455  and a valve spring clip  460 . The valve stem  440  is arranged to run through valve guides  435 A, 435 B. At a lower part of the valve stem  440  above the valve guide  435 B and below valve disc  445 , valve spring  455  is arranged on the valve stem  440  and secured to a lower end of the valve stem  440  by valve spring clip  460 . In the middle of the valve stem  440 , the valve disc  445  is secured by valve disc fixing  450 . Valve disc  445  is formed from a resilient material such as a plastics or rubber material, for example EPDM rubber. In an alternative embodiment, the valve spring  455  may be replaced by a suitable resilient member as would be known to a person of skill in the art. 
         [0064]    The tubular middle chamber  477  has a lower opening which forms a valve seat for lift valve  442  and which lower opening is normally closed by valve disc  445  which is biased by the valve spring  455  into that position. The valve spring  455  is arranged to open the lift valve  442  at a pre-selected pressure on the valve disc  445 . A suitable pre-selected pressure may be that determined by when the tubular middle chamber  477  is full of liquid. 
         [0065]    In an alternative embodiment, the three inwardly projecting ribs  430 A and valve guide  435 A may be removed such that the valve stem  440  is only supported by valve guide  435 B. 
         [0066]    Another embodiment of a connector according to the invention indicated generally at  100  is shown in  FIG. 9 . Connector  500  has an inlet  505 , an upper chamber  562 , a lower chamber  582  and a lift valve indicated at  542 . 
         [0067]    Inlet  505  is supported above upper chamber  562  by a pair of diametrically opposed arms  525  such that a vertical gap  507  is formed between the inlet and the upper chamber  562 . Inlet  505  has an outer thread  510  for engaging with a tap connector (or other pipe fitting) and forms a tapered beak drip  515  which projects downwards into the vertical gap  507 . Arms  525  are arranged so that horizontal gaps between the arms  525  and the vertical gap  507  are sufficient to provide an air break to drain, typical for a standard tundish. 
         [0068]    Upper chamber  562  is shaped by circumferential upper chamber wall  565  and a shelving upper chamber floor  570 . Upper chamber  562  has an open mouth for receiving liquid from the inlet. The upper chamber wall  565  supports arms  525 . Upper chamber floor  570  forms upper chamber floor outlet  575  such that upper chamber floor  570  has an inverted truncated conical shape and such that the upper chamber floor  570  has a funnel shape for directing liquid to the upper chamber floor outlet  575 . Upper chamber wall  565  has three inwardly projecting ribs  530  which support valve guide  535  which is arranged in the centre of the opening to upper chamber  562 . 
         [0069]    The lift valve  542  has the following components: a valve stem  540 , a valve disc  545 , a valve disc fixing  550 , a valve spring  555  and a valve spring clip  560 . The valve stem  540  is arranged to run through valve guide  535 . At an upper part of the valve stem  540  above the valve guide  535 , valve spring  555  is arranged on the valve stem  540  and secured to an upper end of the valve stem  540  by valve spring clip  560 . At a lower end of the valve stem  540 , the valve disc  545  is secured by valve disc fixing  550 . Valve disc  545  is formed from a resilient material such as a plastics or rubber material, for example EPDM rubber. In an alternative embodiment, the valve spring  555  may be replaced by a suitable resilient member as would be known to a person of skill in the art. 
         [0070]    The upper chamber floor outlet  575  forms a valve seat for lift valve  542  and which outlet  575  is normally closed by valve disc  545  which is biased by the valve spring  555  into that position. The valve spring  555  is arranged to open the lift valve  542  at a pre-selected pressure on the valve disc  545 . 
         [0071]    The lower chamber  582  has a ceiling  570 , a first tubular lower chamber wall  580  forming a first lower chamber portion  580 A, a horizontal step  581 , a second lower chamber wall  583  forming a lower chamber flow conduit  583 A, and a shelving lower chamber floor  585 . The ceiling  570  of the lower chamber  582  is formed by the upper chamber floor  570 . The first lower chamber portion  580 A provides a cylindrical volume which receives or accommodates the upper chamber floor  570 , upper chamber outlet  575  and valve  542  in its closed position, particularly valve disc  545  and valve disc fixing  550 . In an alternative embodiment, instead of being cylindrical, first portion  580 A may have a polygonal cross-sectional shape. The lower chamber flow conduit  583 A provides a cylindrical volume  583 A for receiving valve  542  in its open position, particularly valve disc  545 , valve disc fixing  550  and part of valve stem  540 . In an alternative embodiment, instead of being cylindrical, flow conduit  583 A may have a polygonal cross-sectional shape. Lower chamber floor  585  shelves to form an opening for outlet  520  such that lower chamber floor  585  has an inverted truncated conical shape and such that the lower chamber floor  185  has a funnel shape for directing liquid to outlet  5120 . Outlet  520  has a tubular shape, a diameter suitable for attachment to a waste pipe and has a smooth outer surface suitable for engaging with a push fit or universal fitting (not shown). 
         [0072]    The first lower chamber portion  580 A provides a volume for receiving a liquid such as water discharged through the upper chamber floor outlet  575  when lift valve  542  is opened. Lower chamber flow conduit  583 A has a smaller diameter than the first portion  580 A because of step  581 . In an alternative embodiment, the diameter of the flow conduit  583 A may be the same as the diameter of the first portion  580 A such that there is no step  581 . The diameter of the flow conduit  583 A is substantially greater than the diameter of the valve disc  545 , for example 50% to 80% greater, particularly 66% greater such that a volume for liquid flow is provided between the lift valve  542  and the second lower chamber wall  583 . When lift valve  542  is opened, flow conduit  183 A receives lift valve  542  such that there is free flow of water around lift valve  542  within second lower chamber wall  583 . If lower chamber  582  had the typical shape of a tundish, there would be no flow conduit  583 A below first portion  580 A but instead there would be a shelving floor. The insertion of the flow conduit  583 A has surprisingly been found to increase flow rate of liquids through the connector  500  by 50% compared to the connector of  FIG. 1  but with only a 20% increase in the overall length of the connector (the diameter of the connector  500  being the same as the diameter of the connector  100 . 
         [0073]    In an alternative embodiment, the diameter of valve disc  545  may be less than that for outlet  520  such that the valve spring  555  and/or valve disc  545  may be replaced by removing valve spring clip  560 , allowing the lift valve  542  to drop through outlet  520  and out of the connector  500  so that one or more of the components of lift valve  542  may be replaced. 
         [0074]    The increase in overall length of the connector  500  provides the connector with a push fit facility. Without the push fit connection, the length of the connector could be substantially the same as that disclosed in the previous embodiments. 
         [0075]    An embodiment of a shielded connector according to the invention is shown in  FIGS. 10, 11 and 12 . The shielded connector  600  comprises a connector substantially as described in relation to  FIG. 5 . A corresponding sequence of reference numerals for connector  600  have been provided in  FIG. 10  and like features will not be described again. 
         [0076]    As shown in  FIGS. 10 and 12 , the shielded connector  600  comprises a removable shield member  604  seated atop the connector body. The shield  604  has a frustroconical shape having an upper opening  601  which is shaped to fit over inlet  605  and a skirt  603  which is shaped to cover  662  and has a length approximately the same as the length of arms  625 . The shield thus covers the arms  625  and the air gap between the arms so as to block access thereto, whilst preserving the internal spacing required for operation of the device. 
         [0077]    A further embodiment of the shielded connector according to the invention is indicated generally at  700  in  FIG. 13 . The shielded connector  700  has a shield  704  and a connector  702 .  FIG. 13  illustrates the five parts from which the connector  702  is constructed. The five parts are the upper chamber head  790 , the upper chamber body  791 , the upper chamber foot  792 , the lower chamber body  793  and the valve assembly  796 . The four parts  790 , 791 , 792 , 793 , may be joined together by ultrasonic welding or, in an alternate embodiment, by an equivalent technique as might be known to a person of skill in the art. The upper chamber head  790  comprises two circular plastic rings  710 , 712  which are joined by arms  725 . Upper ring  710  is smaller in diameter than lower ring  712  and forms inlet  705  such that upper ring  710  is arranged concentrically above lower ring  712  by arms  725 . Upper chamber body  791  comprises an outer circular plastic ring formed by upper chamber wall  765 , inwardly projecting ribs  730  mounted on an inner surface of upper chamber wall  765  and valve guide  735  which is supported by ribs  730 . The upper chamber foot  792  provides the upper chamber floor  770  and upper chamber floor outlet  775 . The lower chamber body  793  provides the lower chamber  782  as described above for the second embodiment. 
         [0078]    The valve assembly  796  provides the lift valve  742 . Valve assembly  796  is shown in more detail in  FIG. 14 . Valve assembly  796  comprises a valve stem  740  in the form of a shoulder bolt, a valve disc  745 , a valve disc fixing  750  in the form of a self-locking nut, a valve spring  755 , a first upper washer  797 , a second upper washer  794  and a lower washer  795 . The second upper washer  794  has an inverted top hat shape forming a lower projection  794 A. Valve disc  745  has a central aperture  745 A which is shaped to receive not only the shaft of shoulder bolt  740  but also lower projection  794 A such that in use, valve disc  745  is supported by second upper washer  794  and lower washer  795  such that the shape of valve disc  745  is not distorted when valve disc fixing  750  is tightened on shoulder bolt  740 . Additionally first upper washer  797  provides additional support by preventing second upper washer  794  from being pushed up past the shoulder of the threaded portion of the valve stem  740 . The inclusion of separate first upper washer  797  provides a washer function on an upper side of valve disc  745 , allowing second upper washer  794  to provide only a supporting function for the valve disc  745 . In an alternative embodiment, the first and second upper washers  794 , 797  might be arranged below the valve disc  745 . 
         [0079]    Any of the alternative valve types of  FIGS. 4-8  may be substituted for the valves shown in  FIGS. 9-14 . 
         [0080]    Any of the above described embodiments of the invention may be provided with a shield of the kind described above in relation to  FIGS. 11-14 .

Summary:
The invention provides a connector having:
       a. a chamber having an open upper chamber and a lower chamber,   b. an inlet connector and   c. an outlet connector formed in a floor of the lower chamber.       
 
     The inlet connector is supported above the open upper chamber by one or more arms. The upper chamber has an upper chamber floor having an upper chamber outlet, the upper chamber being in fluid communication with the lower chamber by means of the upper chamber outlet. The upper chamber outlet has a non-return valve which is arranged to open at a pre-selected pressure and the lower chamber forms a flow conduit for receiving the valve when it is open. In some embodiments a shielded connector is provided in which a shield is shaped to cover the open upper chamber of the connector. A valve assembly may be provided for use in the connector or shielded connector wherein the valve assembly has a stem, a biasing member for biasing the valve assembly into a closed position, a valve disc for sealing the outlet. An upper washer and a lower washer are disclosed for support of the valve disc such that the valve disc does not distort in use.