Abstract:
A pipe connector system for connecting stub end pipe particularly thermoplastic pipe, the pipe connector system using a common engagement ring and either a flange connector system or a shell-type coupling connector system to interconnect two segments of stub end pipe or to connect stub end pipe to a pipe fitting, the alternate connector systems allowing flexibility and versatility depending on the situation, the common engagement ring being formed as either a full ring or split ring, the split ring permitting the connector system to be utilized when the pipe has a stub end pre-installed.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a pipe connector system that is particularly adapted for the field connection of pipe, particularly thermo plastic pipe. The pipe connector system includes an engagement ring for a stub-end pipe and the alternate use of a removable convoluted flange assembly or a removable shell-type, coupling for interconnecting pipe segments. The interchangeable flange assembly or coupling allows the pipe connector system of this invention to be used in conventional piping systems. The adaptability and flexibility provided by the interchangeable flange system or coupling system makes the combined system ideally suited where alterations in the piping system are inevitable, or where alternatives are required for different situations. 
     For example, in the mining industry, thermal plastic pipe is used to convey particulate matter pneumatically or in a liquid slurry. In addition to frequent rerouting of the transport system, the piping is subject to wear from the abrasive material transported. To maximize usage of the thermal plastic pipe, segments of the pipe might be removed and replaced. A system that allows flexibility in the field replacement of pipe has great advantages in returning the system to operation. 
     As a further example, certain situations may require the use of a shell-type coupling, where the connecting bolts of a flange assembly are not accessible. Additionally, a flange connector may be required to connect a pipe segment to a flanged fitting such as a value. A system having readily available alternatives is therefore desired, particularly in pipe systems that are temporary or subject to alteration. 
     The pipe connectors of this invention include an engagement ring that engages the stub-end of a pipe to seat the alternate interconnectors. The engagement ring is designed to restrain cold flow of material in the end stub to insure a seal is maintained. The common configuration of the engagement ring enables either the coupling or the flange assembly to interconnect the piping. Additionally, the engagement ring is formed as either a full-ring or a split-ring depending on the connector used and the requirements of the interconnection process. 
     For example, where a pipe segment has a stub end pre-installed, a split ring is required for utilization of the interconnectors. However, where a stub end is being installed, a full ring can be slipped over the pipe end, with a flange if desired, before installation of the stub end. In thermoplastic pipe, a stub end can be thermally coupled to the pipe end by thermocoupling equipment. This procedure can easily be performed in the field and is one of the factors that makes thermoplastic piping desirable for many industrial, agricultural and material moving processes. 
     The use of light-weight, convoluted flange assemblies which can be cast from aluminum or ductile iron, is advantageous for savings in transport, storage and installation costs. Similarly, the cast aluminum or ductile iron coupling assemblies are designed and configured to minimize weight for the design strength of the coupling. The flange assemblies and coupling assemblies can be fabricated from other materials such as stainless steel or polymer encapsulated steel for specialty situations. 
     SUMMARY OF THE INVENTION 
     The pipe connector system of this invention includes an interchangeable flange assembly or coupling for interconnecting pipe having a stub end. The pipe connector system is particularly adapted for the interconnection of HDPE (thermo plastic) pipe. The flange connector and coupling connector each use a common engagement ring. The engagement ring may be a full or split ring that forms a contact collar between the connector and the stub. The use of the split ring is particularly advantageous when the thermo plastic pipe is fitted with a stub end at the time of installing the flange connectors. Although the flange connectors can be utilized with a full engagement ring, once installed, the stub end must be cut to allow removal of the engagement ring and flange connectors. By use of the split ring, the flange connectors and the split ring can be removed from the thermo plastic pipe without removing the stub end. When either a full ring or split ring is used with the coupling connectors, the coupling connectors can be removed without removal of the stub end of the pipe. 
     The flange connectors in the flange assembly comprise convoluted flange members that are designed to transmit coupling forces through the engagement ring to the gasket face of the stub at the end of the thermal plastic piping. Similarly, the coupling connectors are designed to interconnect in clamshell fashion and transmit the coupling forces through the engagement ring to the gasket face of the end stub. This is accomplished by the chamfered contact faces of the connectors and the engagement rings, which develop vectors of the force of interconnection developed by the coupling bolts that include opposed forces longitudinal to the pipe and normal to the gasket face, and inwardly radial forces that oppose fluid developed forces within the piping at the stub end. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a prospective view of a flange connector system installed on a segment of thermal plastic piping. 
     FIG. 2 is a prospective view of a coupling connector system on a segment of thermal plastic piping. 
     FIG. 3 is a back elevational view of one of the flange connectors in the coupling connector system. 
     FIG. 4 is a side elevational view of the coupling connectors in the coupling connector system. 
     FIG. 5 is a side elevational view of a full engagement ring that forms part of the pipe connector system of this invention. 
     FIG. 6 is a side elevational view of a split engagement ring that forms part of the pipe connector system of this invention. 
     FIG. 7 is an enlarged partial cross sectional view of a segment of pipe with the flange connectors and split rings installed. 
     FIG. 8 is an enlarged partial cross sectional view of a segment of pipe and the coupling connectors and full rings installed. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, the pipe connector system of this invention designated generally by the reference numeral  10  is shown with a flange connector system  12  installed on a thermo plastic pipe  14 . The flange connector system  12  includes a flange assembly  15  with first and second flange members  16  interconnected by bolts  18 . The flange members  16  engage engagement rings  17 , that in this embodiment is in the form of a split ring unit  22 . The split ring unit  22  includes a pair of semi-circular ring segments  24  for each flange member  16  to effect the connection of two segments  26  of the thermal plastic pipe  14 . Each pipe segment  26  includes a stub end  28  that is thermo-coupled to the pipe segment  26 . 
     Referring to the pipe connector system  10  of FIG. 2, a coupling connector system  32  is shown. The coupling connector system  32  includes a coupling assembly  33  comprising a pair of coupling members  34  that are semi-circular or crescent-shaped in configuration. The coupling members  34  have projecting bolt carriages  36  through which are installed connecting bolts  38  for clamping the two coupling members  34  together around engagement rings  17 , here a full ring unit  35 . The full ring unit  35  comprises a pair of engagement rings  40  (one shown), which seat the coupling members  34  when interconnecting the pipe segments  41 . The coupling connector system  32  engages the stub ends  42  at the end of pipe segments  41  in a manner similar to the split rings  22  of FIG. 1, as described in greater detail hereinafter. 
     Referring to FIG. 3, the elevational view of the backside of one of the flange members  16  is shown. The flange member  16  is of a convoluted type having an outer ring portion  44  an inner ring portion  46  and an intermediate web portion  48  interconnecting the inner ring portion  46  and the outer ring portion  44 . The web portion  48  has a series of bolt holes  50  evenly spaced around the flange member. Adjacent each bolt hole  50  are rib members  52  which provide added strength to the light weight flange member in the larger sizes. The inner ring portion  46  has an incline or chamfered contact surface  54  that engages a complimentary incline or chamfered contact surface  56  on the engagement rings  17  as shown in FIGS. 5 and 6. 
     Referring to FIG. 4 an elevational view of the coupling assembly  33  of the coupling connector system is shown. The coupling assembly  33  has the two crescent-shaped coupling members  34  interconnected by carriage bolts  38  that are seated in projecting bolt carriages  36 . The coupling members  34  have a shell-like housing  58  with a central perimeter ridge  60 , spaced inner rims  62  and a series of ribs  64  between the perimeter ridge  60  and the inner rims  62 . The ridge  60  and ribs  64  provide structural rigidity to the housing  58  to uniformly transmit the clamping forces of the bolts  38  to the engagement rings  17 . 
     The engagement rings  17  as noted are of two types that are interchangeable. The split ring unit  22  is shown in FIG.  6  and includes two identical semi-circular ring segments  24 . The ring segments  24  have a generally “z” cross section with an incline or chamfered contact surface  56  that contacts a complimentary contact surface  54  on the inner ring portion  46  of the flange members  16 , or a similar complimentary contact surface  66  on the inside of the inner rim  62  of the coupling members  34  as shown in FIGS. 7 and 8. The split ring unit  22  is typically used in pairs with a pair of flange members  16 . A single unit  22  is used with a flange member  16 , for example, when a stub end pipe segment is connected to a flanged fitting. 
     Alternately, the engagement rings  17  may comprise the full ring unit  35  shown in FIG.  5 . The full ring unit  35  has a pair of rings  40  each with the same “z” cross section with the incline or chamfered contact surface  56 . The ring unit  35  is ordinarily used in pairs with the flange assembly  15  or coupling assembly  33 . The coupling assembly  33  requires the use of a pair of engagement rings  17 , unless a fitting includes specially prepared coupler stub with an incline or chamfered contact surface matching the contact surface of the coupling members  34 . 
     Referring to the flange connector system  12  of FIG. 7, the pipe segment  26  is shown thermally fused to a stub end  28 . The stub end  28  has an enlarged end stub  68  with a gasket face  70 . A gasket  72  is interposed between the opposed stub ends  28  to seal the interconnection of the pipe segments  26 . The end stub  68  has a shoulder  74  against which a complimentary contact face  76  on the engagement ring  17  is seated. The engagement ring  17  and flange member  16  are slipped over the pipe segment  26  before the stub end  28  is joined when the ring  17  is a full ring unit  35 . A split ring unit  22  can be installed after the stub end  28  is attached and is the usual ring unit used with the flange members  16 . The engagement ring  17  has a first inner cylindrical contact surface  78  sized to slip over the outside of the pipe segment  26  and neck  82  of the stub end  28 , and a second inner contact surface  84  sized to engage the outer perimeter  86  of the stub  68 . 
     When the flange members  16  engage the engagement rings  17  by the incline contact surfaces  54  seating on the incline contact surfaces  56  of the engagement rings  17 , the coupling forces developed by the bolts  18  on tightening are transmitted to the stub end  28  as shown in the superimposed vector diagram in FIG.  7 . 
     In a similar manner, the engagement rings  17  in the coupling connector system  32  of FIG. 8 encompass the stub ends  42  of the segments  41 . The contact face  76  on the engagement rings  17  contacts the shoulder  74  of the stubs  68  to transmit the coupling forces of the coupling members  34  (one shown). The coupling member  34  shown, has opposed inclined contact surfaces  66  in the housing  58 , which seat on the inclined contact surface  56  of the rings  17 . The superimposed vector diagram in FIG. 8 illustrates the manner in which the clamping forces of the connecting bolts  38  are transmitted to the opposed gasket faces  70  through the stub end  42  on tightening the bolt nut  88 . The engagement rings  17  described with reference to FIGS. 7 and 8 may be either split ring units  24  as shown in FIG. 6, full ring units  35  as shown in FIG. 5 or a mix of the two units depending on the circumstances involved in the installation. 
     The operability of either connector system on the common ring design provides a degree of flexibility that is particularly useful in systems subject to modification. 
     While, in the foregoing, embodiments of the present invention have been set forth in considerable detail for the purposes of making a complete disclosure of the invention, it may be apparent to those of skill in the art that numerous changes may be made in such detail without departing from the spirit and principles of the invention.