Abstract:
A cuffed connection system for the transport of a particulate material includes a tube, a conduit, or a duct, and a flexible tube end received and snap fit inter-engaged within the tube, the conduit, or the duct. The snap fit is of a pair of outward circumferential forms each into a complementary receiving groove of a ferrule.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a Continuation Application of U.S. patent application Ser. No. 11/922,143, filed Dec. 13, 2007, now issued as U.S. Pat. No. 7,959,190, which is a U.S. national stage application of PCT/NZ2007/000096 filed May 2, 2007, which claims priority to New Zealand application 547189 filed May 12, 2006, New Zealand application 548174 filed Jun. 27, 2006, and New Zealand application 550870 filed Oct. 26, 2006, which is incorporated by reference herein. 
    
    
     This invention relates to apparatus suitable for transferring materials. More particularly the invention relates to components and assemblies whereby a flexible connection as a duct, passageway or the like (“duct”) is or can be provided and be retained between components for a transfer of material or materials from one component or the other. 
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     By way of example, component to component transfer can involve transfer of particulate materials under pressure, under vacuum, under gravity, or assisted by gravity, from a hopper or the like storage or accumulation vessel via a flexible duct to a conveyor, processing apparatus or plant or to a container. By way of further example, the transfer of particulate materials (whether a powder, granules, prills or other agglomerations) can be moved from a collection or the like vessel or hopper via a flexible connection (with or without the assistance of gravity or gas movement) to a receiving component, plant or the like. In the dairy industry for instance, milk, casein or other powders are to be transferred from a hopper to a downstream apparatus where the treating apparatus or the hopper is subject to vibration. In such a situation the flexible duct as a coupler leads to allows a reduction in the transfer of any vibration from one component to the other. This can be important to avoid damage, errors in weighing, etc. 
     2. Description of the Prior Art 
     It is currently known to hose clamp top and bottom such flexible ducts in a hose like manner about a discharge and/or receive tube. Such flexible ducts or hoses are made of many types of different material depending on the function they are to serve. They can primarily or solely be of a plastics material e.g. polyester, TEFLON™, KEVLAR™, or the like. They can be a fabric (synthetic or natural). They can be some combination of the foregoing. 
     Frequently such transfers are solely or partially under the effect of gravity or the like. There can be an input of vibration to assist discharge and/or movement. In some situations there can be gas or air entrainment. There can even be some gravity and/or vibrational assistance to any such air or gas entrainment system. 
     There is however a difficulty with traditional systems that use an encircling hose clamp about a rigid discharge or receiving tube as this leads to crevices that readily lend themselves to the trapping of materials. In the case of an industry such as the food industry (e.g. dairy included) or pharmaceuticals such capture can give rise to hygiene difficulties particularly if not cleaned regularly. The need to remove and replace a hose clamp makes such regular cleaning cumbersome. 
     SUMMARY OF THE INVENTION 
     The present invention envisages an alternative to such systems where as one connection between a flexible coupling tube or duct and a tube of, or for, component from or to which it is a duct, there is provided a snap lock arrangement reliant upon banding or ferruling at an end region (e.g. cuff) of the flexible tube or duct and a complementary recessed feature the tube of, or for, the component. Such a recessed feature preferably is a rolled ferrule recess to locate the preferably double beaded seal of the flexible tube. 
     It is envisaged that it is possible with such a cuff or the like snap locking feature that there can be a reduction in crevices owing to a more flush relationship in the connected passageways and/or a greater likelihood of regular cleaning owing to the snap fit arrangement. 
     In an aspect the invention is, as part of a particulate solids transport system, an assembly of or having an inter-engagement between a first tube and a second tube partly nested within the first tube, 
     wherein the second tube is a flexible tube with an end region annularly supported by a band or cuff, 
     and wherein the first tube has its end region provided with an annularly profiled set out, 
     and wherein each of (a) the band or cuff and (b) the annularly profiled set out has at least one annular rib directed to the other, and at least one of (a) and (b) has two such ribs so as to have the rib of one engagingly flanked by ribs of the other, 
     and wherein the band or cuff is resilient so as to be deformable inwardly of its tube axis to facilitate insertion or removal of the flexible tube from the first tube but with sufficient return bias to or towards a more relaxed condition such that the rib between two rib engagement holds the tubes against axial separation. 
     Preferably the two ribs are part of said band or cuff. 
     Preferably a resilient cylindrical ring underlies a profiled ring that provides the ribs of the band or cuff. 
     Preferably a fold back of a flexible sleeve of the second tube encloses said profiled ring and cylindrical ring. 
     Preferably the set out of the first tube has been roll formed. 
     Preferably the inner surface of the non-set out region of the first tube and the inner surface of the second tube are in alignment and are at least substantially flush one with the other. 
     In another aspect the invention is a said first tube and/or a said second tube. 
     In an aspect the invention is, in, as part of, or for apparatus to discharge, or to receive a discharge, of a particulate material, a tube, conduit, duct or the like adapted by a profiled zone, band or ferrule recessed to the inside to receive a complementary resilient zone, band or ferrule of a flexible tube, conduit, duct or the like. 
     Preferably there are two annular grooves, each to locate a ridge of the cuff of the connector. 
     Preferably said tube, conduit, duct or the like is a first tube as defined above. 
     Preferably profiled zone, band or ferrule is a roll formed feature. 
     Preferably said roll formed feature is its adaption to locate a double beaded seal (i.e. a cuff or other end modification outwardly of a flexible tube that has two spaced annular beads, ribs or the like). 
     In an aspect the invention is, in, as part of, or for apparatus to discharge, or to receive a discharge, of a particulate material, a tube, conduit, duct or the like adapted by a profiled band or ferrule to the inside to receive a complementary resilient band or ferrule of a flexible tube, conduit, duct or the like (“duct”). 
     Preferably said tube, conduit, duct or the like is a first tube as defined above. 
     Preferably the complementary resilient band requires some inward distortion from which it recovers to allow its fit and hold to the said tube, conduit, duct or the like on its profiled band or ferrule. 
     Preferably said tube, conduit, duct or the like is a first tube as defined above. 
     Preferably profiled zone, band or ferrule is a roll formed feature. 
     Preferably said roll formed feature is its adaption to locate a double beaded seal (i.e. a cuff or other end modification outwardly of a flexible tube that has two spaced annular beads, ribs or the like). 
     Preferably there are two annular grooves, each to locate a ridge of the cuff of the connector. 
     In another aspect the present invention consists in a tube having a ducting locus and profiled region within which a resiliently banded or ferruled end region of a flexible tube or duct is to fit, the tube profiled region having
         (i) an annular channel set out from its ducting locus,   (ii) inwardly directed annular rib set out less than the channel, and   (iii) an annular set out (rebate or channel) out from that annular rib, feature (iii) being closest to that end of the tube from which the flexible duct is or is to be removeably fixed.       

     The features (i), (ii) and (iii) preferably are consecutive i.e. without any interposed other profiling features. In alternative forms however there can be some alternative profiling features. 
     Preferably said tube, conduit, duct or the like is a first tube as defined above. 
     Preferably profiled zone, band or ferrule is a roll formed feature. 
     Preferably said roll formed feature is its adaption to locate a double beaded seal (i.e. a cuff or other end modification outwardly of a flexible tube that has two spaced annular beads, ribs or the like). 
     Preferably said tube is at least substantially rigid i.e. preferably is for example stainless steel. 
     In another aspect the invention is as, or adapted to be used as, a flexible coupling tube to duct particulate material from a discharge tube, conduit, duct, port, or the like and/or to a receiving tube, conduit, duct, port or the like, 
     wherein at least one end region of the tube is resiliently banded or ferruled and has for that banded or ferruled zone an external profile adapted to mate after a return from a distorted form of the banded or ferruled zone in a complementary internal profile of a said discharge tube, conduit, or duct. 
     Preferably said flexible coupling tube is a said second tube as defined above. 
     In another aspect the present invention consists in a flexible duct that has a cuff or other end region adapted to resiliently fit to such a profiled tube at least in part into said channel, over said set in and into said rebate or additional channel. 
     Preferably said duct is of a form substantially as herein described with reference to components assemblies, methods and/or as hereinafter described with or without reference to any one or more of the accompanying drawings. 
     Preferably said flexible coupling tube is a said second tube as defined above. 
     In another aspect the invention is, in, as part of, or for apparatus to discharge, or to receive a discharge of, a particulate material, (A) a tube, conduit, duct or the like and (B) a flexible tube (end received and snap fit inter-engaged within said tube, conduit, duct or the like). 
     Preferably the receiving has required a resilient deformation of an end region of the tube, conduit, duct or the like from which it has relaxed to, or been allowed to relax to, a condition that holds it engaged by profiled interference features with said tube, conduit, duct or the like. 
     Preferably in the relaxed condition there is substantial alignment of the resilient tube, conduit, duct or the like with a wall region of said tube, conduit, duct or the like. 
     Preferably (A) is a said first tube as defined above and (B) is a said second tube as defined above. 
     Preferably said tube, conduit, duct or the like is a first tube as defined above. 
     Preferably profiled zone, band or ferrule is a roll formed feature. 
     Preferably said roll formed feature is its adaption to locate a double beaded seal i.e. a cuff or other end modification outwardly of a flexible tube that has two spaced annular beads, ribs or the like. 
     Preferably the roll formed feature defines a tubed profile region having 
     (i) an annular channel set out from its ducting locus, 
     (ii) inwardly directed annular rib set out less than the channel, and 
     (iii) an annular set out (rebate or channel) out from that annular rib, features (iii) being closest to that end of the tube from which the flexible duct is or is to be removeably fixed. 
     In a further aspect the present invention consists in, in combination, a tube as defined with its profiled region, and a flexible tube or duct having a banded or ferruled end region that complements the profiled region of said tube. 
     Preferably the complementing is as a result of a cuff or other set up feature of the flexible duct, such features being supported by a resilient ring which ensure intimate intermeshing notwithstanding any inward distortion of such resilient ring during a fitting or removal and refitting procedure. 
     In another aspect the present invention consists in, in combination or assembly, a tube and a flexible duct received within said tube, the flexible duct having a resiliently provided end feature to engage as if meshed or otherwise engaged against easy axial dislodgement, such meshing or other such engagement requiring a resilient deformation of the flexible duct end to allow its initial insertion before it assumes and holds its relaxed condition which is commensurate with such meshing or other engagement. 
     In still another aspect the present invention consists in a method of fitting and/or removing a flexible duct or tube which is substantially as herein described in respect of any apparatus, combination or assembly in accordance with the present invention. 
     In another aspect the invention is as, or adapted to be used as, a flexible coupling tube to duct particulate material from discharge tube, conduit, duct, port, or the like and/or to a receiving tube, conduit, duct, port or the like, 
     wherein at least one end region of the tube is resiliently banded or ferruled and has for that border banded or ferruled zone an external profile adapted to mate after a return from a distorted form of the banded or ferruled zone with a complementary internal profile of a said discharge tube, conduit, or duct. 
     Preferably said tube, conduit, duct or the like is a first tube as defined above. 
     Preferably profiled zone, band or ferrule is a roll formed feature. 
     Preferably said roll formed feature is its adaption to locate a double beaded seal i.e. a cuff or other end modification outwardly of a flexible tube that has two spaced annular beads, ribs or the like. 
     In another aspect the invention is plant having a discharge tube or port or a receiving tube or port for the ducted passage of a particulate material, 
     wherein a flexible tube connects the discharge tube to the receiving tube or port, 
     and wherein there is at least one tube to tube connection reliant on a resilient end region of the flexible tube having been deformed to allow its insertion and then assumption of a secure more relaxed condition of said end region in the encircling tube. 
     Preferably said tube, conduit, duct or the like is a first tube as defined above. 
     Preferably profiled zone, band or ferrule is a roll formed feature. 
     Preferably said roll formed feature is its adaption to locate a double beaded seal i.e. a cuff or other end modification outwardly of a flexible tube that has two spaced annular beads, ribs or the like. 
     In another aspect the invention consists in, in a particulate material(s) transport system, a flexible material(s) ducting tube held at least one of its end regions within a less flexible or rigid tube reliant on an annular profile into annular profile inter-engagement 
     wherein there is or has been one or both
         (i) resilient deformation of said end region to a non relaxed condition to allow its insertion to a more relaxed or fully relaxed held condition, and/or   (ii) notwithstanding the profile to profile inter-engagement, the surfaces of the connected tubes are otherwise flush.       

     As used herein “tube” includes any appropriate section but preferably at the inter-engagement contemplates a round relaxed or round rigid section and “tube axis” and “tube locus” takes its meaning therefrom. 
     As used herein the term “and/or” means “and” or “or”, or both. 
     As used herein the term “(s)” following a noun includes, as might be appropriate, the singular or plural forms of that noun. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A preferred form of the present invention will now be described with reference to 
         FIGS. 1   a  and  1   b  which show by reference to a diagrammatic section of one side only of discharge and receiving tubes and a flexible tube, a top connection and a bottom connection, each connection relying on an internal profiling of the discharge tube and the receiving tube and the complementary engagement thereto in an outwardly biased manner a complementary profile of the banded or ferruled region at the end of the flexible tube, both  FIGS. 1   a  and  1   b  showing by reference to the flexible tube proper (i.e. between and into its profiled end features) the alignment thereof at least substantially with the inner wall surface of the discharge tube and the receiving tube respectively, 
         FIG. 2  is a view of a discharge tube or receiving tube to show the features of the end profiling thereof by way of a forming outwardly by any appropriate roll forming or other forming means to define (i) an annular channel set out from its ducting locus, (ii) inwardly directed an annular ribbed set out less than the channel and (iii) an annular set out (in this case a rebate rather than a channel) out from that annular rib, 
         FIG. 3  shows one end of a discharge or receiving tube from the outside, there being shown (to the left) the outwardly rolled features that provide the set ins and rib, etc described with respect to  FIG. 2 , 
         FIG. 4  is a sectional view of a preferred cuff like profiling of the perimeter of the receiving or discharge end of a said flexible tube, the cuff being formed by a fold around and reattachment of part of the flexible preferably non-resilient material of the cuff itself over an underlying resilient ring (e.g. of stainless steel or other resilient material) and a contoured ring best to conform to the inner profile of the end region of the discharge tube or receiving tube, 
         FIG. 5  shows an outside view of the flexible tube feature as shown in  FIG. 4 , 
         FIG. 6  shows the profile ring in the same disposition as is  FIG. 5  that forms part of the fabricated arrangement of  FIG. 5 , 
         FIG. 7  shows similarly to  FIG. 6  the underlying stainless steel or other material resilient ring shown in  FIG. 4 , 
         FIG. 8  is a perspective view of the arrangement of  FIG. 3  as it might be provided as a short length to be welded to a discharge port of appropriate apparatus e.g. a hopper, receiving apparatus or the like, 
         FIG. 9  somewhat analogously to  FIGS. 5 ,  6  and  7  shows from the right the ring of  FIG. 7 , the profiled ring of  FIG. 6  and the cuff of the flexible tube forming material itself as shown in  FIG. 5  or the assembly as shown in  FIGS. 4 and 5 , 
         FIG. 10  shows the manual deformation of one end of a flexible tube in accordance with the present invention to allow its “snap” placement within the profiled end region of a discharge or receiving tube with a complementary profile, 
         FIG. 11  shows the flexible tube engaged within tube for attachment at a port, the flexible tube and complementary profile in part being cut away to show more, 
         FIG. 12  is an enlargement of part of  FIG. 11 , 
         FIG. 13  is a side elevation of an alternative flexible connector this time having similar ends but each of which has a single annular rib supported by a flexible member, 
         FIG. 14  shows the complementary profile spigot to receive either end of a connector of  FIG. 13 , 
         FIG. 15  is a sectional view of part of the section of the flexible connector at the single annular rib, 
         FIG. 16  is an enlargement of the complementary profile of the spigot connector of  FIG. 14 , 
         FIG. 17  is a similar diagram to that of  FIG. 13  but of a double annular ribbed flexible connector of a kind substantially as previously described, this time the connector being shown in the same drawing format as  FIG. 13 , 
         FIG. 18  is a complementary spigot connector for the flexible connector of  FIG. 17 , 
         FIG. 19  is a cross-sectional enlargement of the double annular rib of the flexible connector of  FIG. 17 , 
         FIG. 20  is an enlargement of the profile of the spigot connector of  FIG. 18 , 
         FIG. 21  shows an alternative spigot connector, whether for a single or double rib flexible connector ( FIG. 21  actually showing a region to receive a double annular ribbed flexible connector), but having its other end provided with an outward flange adapted for fixing (e.g. by welding) or being retained on an appropriate opening or port, 
         FIG. 22  is a cross section of part of the spigot connector of  FIG. 21 , 
         FIG. 23  is an exploded view of a variation of a spigot connector such as shown in  FIG. 21  but this time adapted for engagement with multiple components at or about an appropriate opening, 
         FIG. 24  shows the components of  FIG. 23  in section, 
         FIG. 25  shows yet a further variation of the spigot connectors of  FIGS. 21 and 23 , this time being adapted for a square opening at the end remote from the end profiled to receive a double annular ribbed flexible connector, 
         FIG. 26  is a cross-section of the spigot connector of  FIGS. 25 , 
         FIG. 27  is a perspective view of a most preferred form of the ferrule or spigot connector, 
         FIG. 28  is a plan view of the spigot connector of  FIG. 27 , 
         FIG. 29  is an elevational view of the spigot of  FIGS. 27 and 28 , 
         FIG. 30  is the detail at section AA of  FIG. 28  when being viewed in elevation, 
         FIG. 31  is a similar flexible connector to that previously described, 
         FIG. 31A  shows the flexibility of the connector, the connector of  FIGS. 31 and 31A  being adapted for retention by a spigot as in  FIGS. 27 through 30 , 
         FIG. 32  is the detail in section of the resilient ends of the flexible connector of  FIGS. 31 and 31A , 
         FIG. 33  is a plan view of an over sleeve that can be used and, if desired, be attached by any appropriate means (e.g. a hose clamp) or none at all to provide resistance to explosions, 
         FIG. 34  shows such a sleeve in plan view, 
         FIG. 35  shows the sleeve of  FIGS. 30 through 35  in elevation, and 
         FIG. 36  shows with  FIGS. 36A ,  36 B and  36 C appropriate lengths and spacings,  FIG. 36A  being for in line static equipment,  36 B being for offset equipment and  FIG. 36C  being for vibrating equipment. 
         FIG. 37  is a cross-sectional end view of the flexible connector shown in  FIG. 31 . 
         FIG. 38  is an enlarged partial side view of the ends of the flexible connector of  FIG. 31 . 
         FIG. 39  is an enlarged partial side view of the resilient ends of the flexible connector of  FIG. 38 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     In the preferred form of the present invention the flexible tube in accordance with the present invention is of any suitable flexible material (even a woven material). It provides a tube form able to be held substantially in its tubular ducting form so as to provide a wall  1  able to be substantially aligned with a wall  2  of a discharge tube  3  and a wall  4  of a receiving tube  5 . Preferably top and bottom of the flexible tube there is a band or ferrule  6  and  7  (also referred to herein alternatively as a cuff region), respectively, each of which is adapted to conform and engage outwardly into a complementary profiled region  8  and  9 , i.e., spigot, respectively, associated with the members  3  and  5 . 
       FIG. 2  shows one wall of a short tube  10  as shown in  FIG. 8 . 
     Shown in  FIG. 2  is respectively an annular channel set out from the ducting locus, such channel being shown as  11 , an inwardly directed and annular rib  12  set out less than the channel  11  and an annular set out rebate (but it could be a channel)  13  out from that annular rib  12 . 
     The end feature as shown in  FIG. 4  comprises the sleeve of the preferred material of the flexible tube. This material is preferably at least substantially, if not totally, gas impervious as its role is to convey particulate materials rather than to separate particulate materials from any air or gas that may be moving therewith, whether as an entrainment flow or not. 
     The material  1  extends to a foldback region lA from which it can be deformed inwardly as in the inter-engagement form shown in  FIGS. 1A and 1B . 
     The aforementioned cuff region  6 ,  7  as shown, each of which is to act to the outside in its inter-engagement, has a surround first of a resilient ring  14  as a snap band and thereover a profiled ring  15 . The assembly of profiled ring  15  about the resilient ring  14  has been captured onto the material  1  by the fold back region  1 A which is then attached by adhesively and/or stitching at  16 . 
     The resilient ring  14  and the profiled ring  15  need not be adhered one to the other but can be if desired. 
     Such an arrangement shown in  FIG. 4  is then able to inter-engage in a holding engagement with the interior profile of regions  8  and  9 , i.e., the spigot, associated with discharge tube  3  and receiving tube  5 , respectively. 
     A preferred method of inter-engaging is as shown in  FIG. 10 . Here you will see there is a ring  10  having an end region, i.e., the cuff region  6 ,  7  which has fitted therein the resilient ring  14 . The flexibility of the cuff region  6 ,  7  is reliant upon the deformability and resilience of the resilient ring (such as, for example, a snap band)  14 . Upon release from the condition as shown in  FIG. 10  a firm inter-engagement as shown in  FIGS. 1A and 1B  will result. To remove the flexible ring from the inter-engagement as shown in  FIGS. 1A and 1B  there is a similar distortion required to enable its ready removal. 
     In preferred forms of the present invention a suitable plastics material can be used for the profiled ring  15 . The profiled ring  15  is shape retaining but can be resilient so that it can conform to the deformation required of the resilient ring  14  which preferably is of a suitable material e.g. a suitable steel (preferably stainless steel) or could be some appropriate composite or plastics material. 
     Many different materials single or multiple can be used for the flexible seal. One choice for the flexible sleeve proper is Clearflex™ sleeve material which a plastics material having little resilience but being flexible. 
     The sleeve can be formed from a film material, from fibres (e.g. of a non-woven material or a woven material), or some combination of them both e.g. a hybrid. Fibre examples include polyester, nylon, KEVLAR™, PTFE, polyurethane, TEFLON™, aramid, PP, etc. 
     As mentioned hybrids of a woven or non-woven material (i.e. formed from fibres) can be used in conjunction with film. One such example is a KEVLAR™ woven fabric and a polyurethane film. 
     Depending on usage preferably the inner surface of the flexible sleeve is to a food grade. 
     Alternative materials to any of those described can be used. There is no need for the material of the flexible tube to be homogeneous, i.e. it can have localised regions of different properties (e.g. material, rigidity, etc) if that is desirable in a particular application. 
     Accordingly, any suitable choice of material or materials or variation of the same material or same materials can be used as can any appropriate hybridisation of the structure for example a combination of KEVLAR™/SEEFLEX40 when cuffed by a cuff of the present invention provides much greater explosive resistance than a conventionally fitted SEEFLEX™ flexible coupler. SEEFLEX is a trademark of BFM Fitting, Auckland, New Zealand and is a clear polyester based thermoplastic polyurethane alloy material. 
     A person skilled in the art will appreciate how with the substantial flushness possible as shown in  FIGS. 1A and 1B  there is little in the way of collection areas for particulate materials such as food powders. These should be easily dislodged by regular cleaning without disassembly in conjunction with the vibrational nature of the structure. Periodic removals of the flexible tube are easy as there is no encircling hose clamp to remove and replace. Removal and replacement is simple. 
     In some forms of the present invention some additional outside tethering arrangement can, if desired, be provided to ensure that any failure in use is unlikely to be catastrophic. Such external tethering however is not preferred. 
     Whilst there has been description of a particular profiling of the end of each of the tubes in question, other profiled end forms are within the scope of the invention that provide for appropriate retention. These may include one or more annular rib. They may include one or more channel. It is preferred that the profiling be of an annular nature rather than helical or otherwise. 
     It is believed that the present invention provides industry with a useful alternative to existing apparatus and methodologies. 
       FIGS. 13 through 16  as described show a single annular rib  12  at each end of a flexible connector adapted to be received by a complementary profile. Each rib is analogously made to the twin rib form already described. 
     Similar set outs etc.  17  exist for the single annular rib interengagement as for the double annular rib interengagement previously described. 
       FIGS. 17 through 20  show in a similar style to  FIGS. 13 to 16  a double annular rib series of drawings. 
     Irrespective of whether or not the annular connector is single ribbed at one end or double ribbed, or as a hybrid of both, persons skilled in the art will appreciate how the system works. 
       FIGS. 21 and 22  show a variation of the spigot of  FIGS. 18 and 20  to the extent that there is provided an outwardly extended flange  18  at the bottom adapted itself to be welded to an appropriate surface about an opening or to be captured by an appropriate capture device. 
       FIG. 23  shows a variation on such a theme, i.e. with a structure adapted to seal with a seal  19  into a bottom end of a connector at  20 , the connector of  FIGS. 23 and 24  being adapted to sit down on the appropriate annular seal  19  itself seating to a member  21 . 
       FIGS. 25 and 26  show how a complementary member such as shown in  FIG. 20  can instead of maintaining the same general tubular form can evolve into other geometric forms. In the case of  FIGS. 25 and 26  it evolves into a square tubular form  22  adapted for attachment to a square port or conduit. 
       FIGS. 27 through 30  show a most preferred form of the spigot  8 ,  9 . The spigot  8 ,  9  can be of a metal (steel or SS) construction, a plastic construction, or a construction that includes a combination of materials. The form of the spigot  8 ,  9  depicted in  FIGS. 27-30  has an inturned region  23 , thus meaning that the inwardly directed ridge  24  separates two complete annular retention grooves  25  and  26  able to accommodate respectively lip parts  27  and  28  respectively of a flexible connector end as shown in  FIGS. 31 ,  31 A and  32 . 
     This shaping of the distal part to match the connector does two things—ensures a seal on two lip parts ( 27  and  28 ) and ensures less gap with the connector exteriorly to collect dust and dirt. 
     An oversleeve, for example, of explosion suppressing Kevlar, can be provided to slip over the flexible connector and, if desired, extend over the spigot  8 ,  9  at each end thereof. If desired, the oversleeve can be clamped, for example, by any clamping method onto the surface  29 , or the oversleeve can be left free but with sufficient lapping to ensure adequate explosion protection. 
       FIG. 31A  shows the flexibility of the connector but even though it is connected, attention should be paid to  FIGS. 36A through 36C .
     Ø inside diameter of both spigot and connector ends in mm—options suggested being in Table 1   AL separation of spigots in mm   CL connector length in mm   H is spigot or ferrule head/retention profile length (e.g. preferably about 35 mm)   T Is spigot or ferrule tail length (e.g. preferably about 52 mm)
 
Suitable internal diameters for the tail and inside of each end of the connectors is preferably one of the following from the Table.
   

     
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Ø (Diameter) 
                 Length (CL) 
               
               
                   
                   
               
             
             
               
                   
                 100 
                 150 
               
               
                   
                 150 
                 150 
               
               
                   
                 200 
                 200 
               
               
                   
                 250 
                 200 
               
               
                   
                 300 
                 300 
               
               
                   
                 350 
                 300 
               
               
                   
                 400 
                 300 
               
               
                   
                 450 
                 300 
               
               
                   
                 500 
                 300 
               
               
                   
                 550 
                 300 
               
               
                   
                 600 
                 300 
               
               
                   
                 650 
                 300 
               
               
                   
                   
               
             
          
         
       
     
     For a diameter Ø (e.g. which can be any of those shown in the Table), the distance AL between the spigots relates to a connector length CL as follows: 
     Spacing AL for in line static equipment as shown in  FIG. 36A  should be the connector length CL minus 10 mm. For the off set equipment of  FIG. 36B , the spacing AL should be the connector length CL minus 20 mm. For vibrating equipment the spacing AL should be the connector length CL minus 40 mm. 
     Advantages Include: 
     Advantages from at Least Preferred Embodiments of the Invention are: 
     More Hygienic 
     
         
         
           
             Perfect fit 
             No crevices 
             No build up of product
 
Less Susceptible to Damage
 
             no hose clips needed 
             no tools needed 
             no damage as a consequence
 
Explosion Resistant
 
             can be provided with better resistances to internal explosions than conventional flexible couplers
 
Fast Simple Replacement
 
Effective Sealing
 
             no leaks 
           
         
       
    
     In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art. 
     The invention being thus described, it will be apparent that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be recognized by one skilled in the art are intended to be included within the scope of the following claims.