Abstract:
A dispenser apparatus for a curable liquid material is disclosed. The apparatus comprises a flexible bag defining a first compartment for accommodating a first component of a curable liquid material, and a second compartment for accommodating a second component of the curable liquid material and adapted to communicate with the first chamber to enable mixing of the first and second components to initiate curing of the curable liquid material. A first clamp temporarily prevents mixing of the first and second components, and an elongate nozzle communicates with the second compartment to dispense the mixed curable liquid material therefrom. A second clamp temporarily prevents passage of the curable liquid material from the second compartment to the nozzle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/391,539 filed May 2, 2012, which claims priority to PCT International Application No. PCT/GB2010/050989 filed on Jun. 14, 2010, which claims priority to European Patent Application No. 09168430.8 filed on Aug. 21, 2009, European Patent Application No. 09168429.0 filed on Aug. 21, 2009, Great Britain Patent Application 1004216.6 filed on Mar. 15, 2010 and Great Britain Patent Application 1009450.6 filed on Jun. 7, 2010, all of which are fully incorporated by reference herein. 
     STATEMENT CONCERNING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a filler assembly for cable glands and relates particularly, but not exclusively, to such a filler assembly for filling cable glands for use in hazardous areas. 
     BACKGROUND OF THE INVENTION 
     Many cable glands for use in connecting a cable to an enclosure in hazardous areas need to be filled with a compound which provides a barrier against the effects of an explosion occurring within the enclosure to which the cable gland is attached. The barrier is typically formed from a two-part clay-filled epoxy compound. The two component parts of the compound need to be thoroughly mixed with each other prior to fitting into the gland, and the resulting putty like material needs to be packed between the individual conductors in the cable. Such an arrangement is disclosed in GB 2258350. 
     This known arrangement suffers from a number of drawbacks. Firstly, the cure time of the putty like material is chosen to be relatively long, in order to enable it to be manipulated into the spaces between the individual conductors before curing becomes advanced. As a result, the filled cable assembly must be left undisturbed for a significant period, usually several hours, especially if mixed at low temperatures. Also, the components of the filler material sometimes contain hazardous materials which become harmless when the filler material is mixed. Persons mixing the components of the putty like filler material may come into contact with these hazardous materials during mixing, and air can become trapped within the cable gland by the filler material which may cause the barrier formed by the filler material to fail in the event of an explosion. Filling of the cable gland is also relatively difficult, especially in the case of small cable glands. 
     GB 765082 discloses an arrangement for insulating a splice between two stranded connectors in which resinous material is introduced from a capsule having an elongate tip. However, this arrangement suffers from the drawback that it is not suitable for filling cable glands, since the introduction of a material which is sufficiently fluid to penetrate between the individual conductors of a cable would cause material to flow along the conductors along the interior of the cable, which would prevent the cable gland from being sufficiently filled to expel all of the air from the cable gland to avoid air voids. 
     Preferred embodiments of the present invention seek to overcome one or more of the above disadvantages of the prior art. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the present invention, there is provided a filler assembly for filling a cable gland, having a plurality of cores of at least one cable extending therethrough, with curable liquid material, the assembly comprising: 
     (a) a dispenser apparatus for a curable liquid material, the apparatus comprising: 
     a body adapted to define at least one first chamber for accommodating a first component of a curable liquid material, and at least one second chamber for accommodating a second component of said curable liquid material, wherein mixing of said first and second components initiates curing of said curable liquid material; and 
     at least one elongate dispenser device adapted to dispense said mixed curable liquid material therefrom between a plurality of cores of at least one cable; and 
     (b) at least one flexible barrier member having at least one respective aperture therethrough and adapted to engage a plurality of cores of a cable to provide a barrier to passage of said curable liquid material along said cores. 
     As a result of the provision of at least one elongate dispenser device, dispensing of the curable liquid can be more carefully controlled, as a result of which less viscous and faster curing liquid material can be used than in the prior art. This therefore provides the advantage of enabling more rapid formation of a filled cable gland incorporating the material, while also allowing the liquid material to be introduced into the cable gland in such a way that the air is expelled from the cable gland to avoid air voids, which could lead to failure of the cable gland in the event of an explosion. In addition, with the present invention, the curable material can be dispensed into the assembled gland, i.e. the cable gland can be filled with the conductors of the cable in a connected state, as a result of which the electrical integrity of the joint can be ensured, whereas the putty like compound of the known arrangement must be molded around the conductors of the cable with the gland disassembled, as a result of which the cable cores can not be electrically connected. The provision of at least one barrier member for restricting the extent of penetration of said curable liquid material along the cable cores provides the advantage of enabling highly flowable curable liquid material to be used, while also enabling filling of the cable gland. 
     The body may be flexible. 
     This provides the advantage of making the apparatus easier and less expensive to manufacture. 
     The assembly may further comprise a first component of a curable liquid material in at least one said first chamber, and a second component of said curable liquid material in at least one said second chamber. 
     The curable liquid material may be adapted to change colour as a result of curing thereof. 
     This provides the advantage of providing a visual indicator to the user when the cable gland filling process is complete. 
     The assembly may further comprise a cover member for covering an external screw thread of a cable gland to prevent said curable liquid material coming into contact with said screw thread. 
     The cover member may be adapted to prevent curable liquid material from penetrating an end face of the cable gland. 
     At least one said barrier member may comprise a respective flexible member having at least one aperture therethrough for engaging at least one core of at least one cable. 
     At least one said barrier member may have a respective tapering portion. 
     According to another aspect of the present invention, there is provided a method of filling a cable gland with curable liquid material, the method comprising: 
     using a filler assembly that includes: 
     (a) a dispenser apparatus for a curable liquid material, the apparatus comprising: 
     a body adapted to define at least one first chamber for accommodating a first component of a curable liquid material, and at least one second chamber for accommodating a second component of said curable liquid material, wherein mixing of said first and second components initiates curing of said curable liquid material; and 
     at least one elongate dispenser device adapted to dispense said mixed curable liquid material therefrom between a plurality of cores of at least one cable; and 
     (b) at least one flexible barrier member for having at least one respective aperture therethrough and adapted to engage a plurality of cores of a cable to provide a barrier to passage of said curable liquid material along said cores; 
     locating at least one said barrier member in the cable gland; and 
     locating an outlet of at least one said dispenser device in said cable gland and dispensing curable liquid material therefrom so as to expel air from the cable gland. 
     The step of locating at least one said barrier member in the cable gland may comprise locating at least one said barrier member around at least one said core of at least one said cable. 
     The assembly may further comprise at least one barrier apparatus for temporarily preventing passage of the curable liquid material from the or each second chamber to at least one dispenser device. In addition, the barrier apparatus may comprise at least one releasable clamp. 
     According to another aspect of the invention, there is provided a cable gland for receiving a plurality of cores of at least one cable, the cable gland comprising: 
     (a) a body adapted to have a plurality of cores of at least one cable extend therethrough; 
     (b) a dispenser apparatus for a curable liquid material, the apparatus comprising: 
     a body adapted to define at least one first chamber for accommodating a first component of a curable liquid material, and at least one second chamber for accommodating a second component of said curable liquid material, wherein mixing of said first and second components initiates curing of said curable liquid material; and 
     at least one elongate dispenser device adapted to dispense said mixed curable liquid material therefrom between a plurality of cores of at least one cable; and 
     (c) at least one flexible barrier member having at least one respective aperture therethrough and adapted to engage a plurality of cores of a cable to provide a barrier to passage of said curable liquid material along said cores. 
     The elongate dispenser device may be sufficiently stiff to be inserted between the cores of the cable in the vicinity of the flexible barrier member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A preferred embodiment of the invention will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings in which: 
         FIG. 1  is a perspective view of a dispensing apparatus embodying the present invention; 
         FIG. 2  is a partially cut away perspective view of a cable gland having a filler formed using the apparatus of  FIG. 1 ; and 
         FIG. 3  is a cross sectional view of the filled cable gland of  FIG. 2  with a thread protector in place. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A preferred embodiment of the invention will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings in which: 
       FIG. 1  is a perspective view of a dispensing apparatus embodying the present invention; 
       FIG. 2  is a partially cut away perspective view of a cable gland having a filler formed using the apparatus of  FIG. 1 ; and 
       FIG. 3  is a cross sectional view of the filled cable gland of  FIG. 2  with a thread protector in place. 
     Referring to  FIG. 1 , a dispenser apparatus  2  embodying the present invention and for use in filling a cable gland  4  ( FIG. 2 ) with curable liquid material  6  comprises a body of suitable transparent flexible plastics material defining a flexible bag  8  having a first compartment  10  for accommodating a first component of a liquid curable material  6 , and a second compartment  12  for accommodating a second component of the material  6 . A first clamp  14  temporarily separates the first compartment  10  and second compartment  12  to thereby prevent mixing of the first and second components of the material  6 . The first and second components are coloured differently (for example blue and yellow) so that thorough mixing of the first and second components produces a green liquid, thereby providing a visual indication when thorough mixing of the first and second components has occurred. Mixing of the first and second components together causes gelling of the material and initiates curing of the curable liquid material  6 . 
     The dispenser apparatus  2  is also provided with an elongate hollow nozzle  16  extending from the second compartment  12  such that dispensing of the mixed curable liquid material can be carefully controlled. In particular, the nozzle  16  can be inserted a considerable distance into the cable gland  4  and between individual core conductors  20  of the core of a cable  22  attached to the cable gland  4  ( FIG. 2 ) so that the liquid material  6  can be highly flowable and fast-curing, as a result of which the cable gland  4  can be rapidly filled and air entrapment by the liquid material  6  minimised. A second clamp  18  temporarily prevents material flowing from the second compartment  12  into the nozzle  16 , so that dispensing of the material  6  can be prevented until thorough mixing together of the first and second components has occurred. 
     The flexible bag  8  is formed from two sheets of material welded together along all but one of their edges to form a bag having an open mouth, which is then mounted to the nozzle  16 . The second clamp  18  is then mounted to the bag adjacent to the nozzle  16 , and the second component of the material  6  is dispensed into the second compartment  12 . The first clamp  14  is then mounted to the bag to seal the second component in the second compartment  12 , and the first component is then dispensed into the first compartment  10 . The open edge of the bag is then sealed to seal the first component in the first compartment  10 . 
     Referring to  FIGS. 2 and 3 , the cable gland  4  to be filled by means of the dispenser apparatus  2  of  FIG. 1  comprises a threaded outer connector  24  for threaded connection to an enclosure (not shown) and a compound tube  26  rotatably mounted within the outer connector  24 . A cable connector  28  is mounted to the end of the cable  22  and is connected to the outer connector  24  by means of cooperating screw threads (not shown). 
     A ring  30  abuts the cable connector  28  and a flexible seal  32  is located around the core conductors  20  of the cable  22  and compressed between the compound tube  26  and ring  30  for limiting the extent of penetration of curable material  6  into the cable gland  4  before curing of the curable material  6 . The flexible seal  32  comprises a generally frusto-conical body of elastomeric material having an aperture (not shown) therethrough for engaging the core conductors  20  of the cable  22 . The aperture in the seal  32  is sized such that it stretches to pass around the core conductors  20  to tightly engage the core conductors  20  to form a reasonably effective barrier to passage of the material  6  along the space defined between the core conductors  20  and the compound tube  26 . 
     Referring to  FIG. 3 , a thread protector  34  formed of elastomeric material such as rubber is located over the external screw thread of the outer connector  24  of the cable gland  4  prior to filling of the cable gland with curable material  6 . The thread protector  34  has a hollow rim  36  for catching excess curable material  6  which may flow out of end  40  of the cable gland  4  during the filling procedure, and an inner circular rim  38  which prevents penetration of curable material  6  into the gap between the outer connector  24  and the compound tube  26 . This ensures that the compound tube  26  complete with cable connectors  28  can be removed from the outer connector  24  after curing of the material  6 . 
     The process of filling the cable gland  4  of  FIGS. 2 and 3  by means of the dispenser apparatus  2  of  FIG. 1  will now be described. 
     In order to fill the core of the cable gland  4  with curable material, the flexible seal  32  initially placed over the core conductors  20  of the cable  22  so that the seal  32  tightly grips the core conductors  20 . The outer connector  24  with compound tube  26  are then mounted to the ring  30  and cable connector  28  to compress the seal  32  between the ring  30  and compound tube  26 . As a result, the flexible seal  32  acts as a barrier to penetration of the curable liquid material  6  into the interior of the cable gland  4 . 
     The first clamp  14  is then removed from the dispenser apparatus  2  and the second clamp  18  left in place, to enable thorough mixing of the first and second components of the curable liquid material  6 . The first and second components are coloured blue and yellow respectively, a result of which the curable liquid material  6  is bright green when it is thoroughly mixed. The second clamp  18  is then removed, and the outlet of the nozzle  16  is placed at a location near the seal  32 . The liquid material  6  is then dispensed through the nozzle  16  into the space between the core conductors  20  of the cable  22  and into the space around the core conductors  20  inside the compound tube  26  of the cable gland  4 , where its movement along the axis of the cable gland  4  is restricted by the flexible seal  32 . The location of the outlet of the nozzle  16  near the seal  32  causes air to be expelled from the cable gland when the curable liquid material  6  is dispensed from the nozzle  16 . The seal  32  provides a sufficient barrier to penetration of the material  6  to hold back the curable material until it begins to gel and support itself. At the same time, the thread protector  34  protects the external thread of the outer connector  24  from excess curable material and prevents penetration of the liquid curable material between the outer connector  24  and the compound tube  26 . The material  6  is arranged to change colour to dark green when it is cured, so that a visual indication is provided when the curing process is completed. 
     It will be appreciated by persons skilled in the art that the above embodiment has been described by way of example only, and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the invention as defined by the appended claims.