GB2186443A - Transit for cables and pipes - Google Patents

Abstract

In a lead-through transit for cables or pipes 3 comprising a frame 1 filled by blocks 4,5 the lead through blocks 4 are of resilient material and comprise complementary half-blocks 40 and at least one member 41 that sits in a recess 43. The member 41 comprises a solid core 45, rings 46 and an outer ring 47 complementary to the seating recess 43. The core 45 and a selected number of rings 46 can be removed to provide a passageway sized to suit a cable 3. The member 41 may be used complete in the half-blocks 40 to provide a blanking block or a solid blanking block 5 may be provided for the system. By this arrangement only one type and size of half-block and member need be provided for a wide range of cable sizes. <IMAGE>

Description

SPECIFICATION Improved transit for cables and pipes Description: This invention relates to a transit providing a lead-through for electric cables or pipes that are required to extend through an opening in a wall, bulkhead, partition or the like. This invention concerns certain improvements in a particular kind of transmit as hereinafter defined and which is for use with cables, wires, pipes or tubes or the like elongate elements commonly used in an installation for conducting electricity, service commodities such as gas, oil or water, or enclosing such service lines. For convenience herein, the term "cable" is used and should be interpreted inthecontextto include all such aforesaid elongate elements.

This invention is particularly concerned with a transit of the kind now defined as comprising a rectangular metal frame defining an opening through which the cables are to extend, a series of sets of modular blocks for assembly in rows within the frame opening, the blocks being adapted for surrounding each cable orfor blanking off a modular space, and a compression and packer assembly for mounting i n the frame opening to clamp the assembled blocks together and around each cable with the compression and packer assembly completing filling of the frame opening.

Such defined kind oftransitforcables is well known and is disclosed in Patent Specification GB 1,049,621.

Typically,transits of the defined kind are used in a wide range of applications and are installed in various environments including hazardous and have to meet specific regulationsforfire-proofor flame-proof or gas-tight installations. Usually, a transit has to be assembled on site and often the working conditions at the installation site are difficult in many respects, such as:- access and location; the numbers, types and sizes of cable; limited working space and lack of access to both inlet and exit sides of the lead-through; and, ambient temperature, weather and environmental conditions.

Conventionally in transits of the defined kind, in each series of the modular blocks, each block is of square section and has a length substantially the same as the depth of the metal frame into which the blocks are assembled in an array of superimposed rows. Each block in a set of blocks has the same external dimensions and a plurality of blocks from one set will completely fill one row across the inside of the frame. To provide blanks at locations in a row where no lead-through is required, each set includes solid blank blocks for assembly in the row.For a cable lead-through, the blocks have a through hole of a diameter corresponding to the diameter ofthe cable to be surrounded by the block, and to facilitate fitting and assembly each such block is formed in two complementary halves with semi-cylindrical recesses that, when aligned, provide the lead-through hole in which the cable is seated.

The known cabletransits of the defined kind have a sized lead-through blocks corresponding to each nominal cable size, and as a resultto fit and install a transitforevenasmall numberofcables,itis essential to have a large numberof lead-through blocks on site, particularly as cables are often not to the nominal given size and alternative lead-through blocks have to be used to correspond to the actual diameter ofthe cable, and possibly to accommodate cables which are out-of-round.

This problem ofthe large numbers of blocks which have to be available on site and produced by the manufacturer leads to various other problems and disadvantages in practice, bearing in mind the difficult conditions often arising at the installation site, and often the remoteness of the site where a complete range of sized lead-through blocks may not be readily available for immediate use. In addition, thefitterworking in such hazardous environments is hampered in efficiently completing the installations, and this increases costs and may effect costings arising from equipment down time.

It is an object of this invention to provide a transit for cables or pipes of improved construction which avoids this known disadvantge of providing sized lead-through blocks for fitting to respective sized cables or pipes.

It is a further object of this invention to provide an improved transit for cables or pipes which is simple and easy to install on site and by which the numbers of component parts required to be handled by a fitter or stocked bythe user are minimised.

Other objectives and advantages features ofthis invention will be referred to later herein.

According to this invention, we provide a transit of the defined kind for cables or the like characterised in that the lead-through block comprises two complementary half-blocks and an annulus member forengagementwithin complementary semi-cylindrical seatings formed in the half-blocks, the annulus member comprising a cylindrical core having a plurality of annuli in the form of concentric cylindrical sleeves of specific radial thickness nested within each other on the core, the arrangement of the lead-through block being such that to provide a cylindrical lead-through passageway for a cable of specific diameter the core is removed from the centre of the annulustogetherwith (if necessary) selected next encircling sleeves until the sized passageway is formed through the annulus member thereby providing a sized insertfor receiving the specific diameter cable therethrough and the sized annulus being inserted and engaged intheseatings ofthe half-blocks.

By this invention, all that is necessaryto provide for each modular size of lead-through block is the two half-blocksandtheannulusmember. Inusefor installing thecable,the annulus memberis usedto provide a wide range of cylindrical passageway by discarding the core and any others of the concentric annuli sleeves that are of a diameter smallerthan that required for the particular cable. Thus, as will be appreciated, the need to have many sized lead-through blocks on site as at present is necessary is totally avoided.

Preferably, the core and encircling annuli sleeves are connected to each other by shearwebs or other portions that are easily ruptured to part of the core and encircling annuli sleeves from each otherwhilst maintaining the integrity ofthe annul us member during intermediate uses such as storage, handling and shipping.

Conveniently, the annulus member includes an outerannuliwhich serves an an outer casing and this casing sleeve may be thickerthan the inner concentric annuli. This casing annuli serves as an outer reinforcementforthe annulus member and is designed to firmly locate the annulus after it has been sized by removal of inner annuli sleeves and/or the core in the seatings formed in the half blocks.

In the simplestform oftransit according to this invention, only one annulus member may be provided in the lead-through block. However, it is within the scope of this invention to provide two such annulds members, each respectively located in complementary semi-cylindrical seating form in the half-blocks at axially spaced apart positions.

For convenience of fitting the annulus memberto cables and pipesorthelike,theannulisurrounding the core may have a radial slittherethrough to enable the annulus member to be resiliently opened and sprung over the cable of pipe. Such an arrangement for ease of fitting is useful in renewing or maintaining existing installation where the free end of cables or pipes cannot be reached. This arrangement is also very useful in applications of transitwhich may not be required to meetthe particular high specificationsforfire or explosion resistance or watertight applications.

With the invented lead-through block, it is possible to use it as a blanking block by maintaining the annulus member complete, thus the provision of conventional solid blank blocks can be obviated.

Otherfeatures ofthis invention will now be described with reference to exemplary embodiments depicted in the accompanying drawings wherein: Figure lisa front elevation of a cable transit according to this invention shown in the assembled position with cables in situ; Figure2 is a partly sectioned side view of the cable transit shown in Figure 1; Figure 3is an isometric view of part ofthe compression and packer assembly; Figure 4is a detail sectional view of part of assembly shown in Figure 3 and as indicated therein; Figure 5 is an isometric view of the compression plate ofthe compression and packerassembly; and Figure 6is a detail isometric view ofthe component parts of a lead-through block.

With reference to the drawings of Figures 1 and 2, the improved cable transit comprises a rectangular frame 1 defining an opening 2through which cables 3 of different sizes extend. Each cable 3 is held within a lead-through block4 whilst solid blank blocks 5 or blanking lead-through blocks 4' fill the modular spaces ofthe opening where no cable is present. In known manner, the frame is for mounting or support in an aperture in a bulkhead or partition orthe like (not shown) and the numbers and sizes of cables may vary from one installation to another. For simplicity of explanation of this invention, only a small number of cables are depicted and the assembly is not as complex as found in practice where tens of cables may haveto be accommodated and installed at the site location.

In this embodiment, there is depicted three series of modular sized sets of blocks designated by the suffixes a, band c. Each series set has blocks of substantially square section with the respective width and height dimensions of each set being selected to a common multiple so that a plurality of blocks of each set will complete a row orfill a modular space within the frame. Typical suitable modular dimensions are 90mm, 60mm and 30mm forthe square section blocks.

Each set of blocks is assembled in a row and to separate and supportthe assembled rows, stay plates 6 extend therebetween to locate on the marginal edges of the side walls of the frame 1.

In addition, the opening 2 is closed buy a compression and packer assembly 7 which clamps and holdsthe rows of blocks in place and applies pressure to the blocks.

With reference also to Figures 3,4 and 5, the compression and packer assembly 7 comprises a pressure plate 8, three compression blocks 9,10 and 11 each having a respective compress stud 12,13 and 14 extending therethrough. Each compression block 9,10 and 11 has a respective rear support plate 15,16and 17 againstwhichthe rear head of each respective stude 12,13 and 14 engages. Each stud 12,13 and 1 4extends through the respective block and through aligned openings in afrontsupport plate 18 with respective nuts 19,20 and 21 being in threaded engagement with the free end of the associated stud projecting through the front support plate 18.

The pressure plate 8 is a rigid body having a planar underside 22 for engagement with the upperfacesof the top row of blocks 5a, and an edge flange 23 on each side of the plate 8 provides location ledges overlying the upper marginal edges of the blocks as well as providing outer end lug portions that extend outwardly and engage outer faces ofthe sides ofthe frame 1. The topside ofthe plate 8 has a flat central portion 24 and opposed inclined portions 25.

Each of the compression blocks 9,10 and 11 are made of a resilient material and the outer blocks 9 and 11 haverespectivethrough holes 26,27 that extend transverse and spaced from the respective axes of the compression studs 12 and 14. As best shown in Figure 4, a respective limit pin 28 is mounted in each through hole 26,27 and this pin 28 is arranged to engage the inner face ofthe top of the frame 1 and the inclined portion of the pressure plate 8so as to limit the degree of deformation ofthe blocks 9 and 11 when compression loading is applied to the blocks in the direction of the axis ofthe limit pins as later explained.

The upper wall 29 oftheframe 1 is provided with a central clearance hole 30. A hexagonal shaped boss 31 is rigidly mounted on the upperwall 29 and projects therefrom aligned with the clearance hole 30. The boss has an internal blind threaded bore 32 and a compression bolt 33 is in threaded engagement within the bore 32 with the head 34 of the bolt 33 being accessible through the clearance hole 30 for rotation by a suitable tool. As should be appreciated, the bolt 34 can be unthreaded to extend into the void below the boss 31 when the central compression block 10 is notfitted, and the head 34of the bolt will engage with the central portion 24 ofthe plate 8.

The compression blocks9and 11 aresimilarand haveinnertaperfacesthatlieadjacenttothe opposed side faces of the central compression block 10. The central block loins generally in the form of a wedge with the opposed side faces diverging from the front of the block as well as converging towards each othertowards the underside of the blockto present a flat underside face 35 engaging the flat central portion 24 of the plate 8. The innertaperfaces ofthe outer compression blocks 9 and 10 are complementary to the wedge faces of the central block 10. The underside faces ofthe compression blocks 9 and 10 are inclined and complementaryto the respective inclined portions 25 ofthe plate 8.

With reference also to Figure 6, each lead-through block4 is similar and comprises two complementary half-blocks 40 and two annulus members 41 thatare assembled together as later described either with the cable extending therebetween orto serve as blanking lead-through blocks as generally depicted in the view of the cable transit shown in Figure 1.

All ofthe modular blocks including the lead-through half-blocks 40 and the annulus members 41 are formed from a resilient material which may be the same material as used for the compressed blocks 9,10 and 11. Each half-block 40 is similar and complementary having semi-cylindrical clearance passageways 42 exending axially. Each half-block has semi-cylindrical recesses formed therein to provide two axiallyspaced seatings 43 and 44 in which each respective annulus member 41 can be received with the cable or pipe extending through the clearance passageway 41.

Each annulus member 41 is similar and comprises a central solid core 45 which is encircled by a series of concentric annuli sleeves 46 each of increasing internal diameter, and the radial thickness of each sleeve 46 is intended to be to specific sizes to meet the range of nominal cable or pipe sizes as may be required. In the schematic drawing of Figure 6the numbers of annuli are shown asfewforthe purposes of clarity and to simplifythis description.

The outer annuli of the annulus member41 provides a slightly thicker outer casing sleeve 47 which preferably has the same radial thickness as the depth ofthe recess 43. Each ofthe annuli and the core are connected together byweakwebs 48 as shown in broken lines, and are separable by pushing the individual elements apart so that the core 45 can be removed leaving a small central passagewayfora cable sized for that core diameter. For larger cables, successive ones ofthe annuli sleeves 46 may be separated until onlythe largest internal diameter which is defined by the innerface of the outer casing sleeve 47.This internal diameter corresponds to the diameter of the passageway 42 so that the lands 49 extending on either side of each seating 43 are contiguous with the inner face ofthe casing sleeve 47.

Aswiil now be understood, the lead-through block 4 provides a lead-through passagewayfor a range of cable or pipes sizes, and by removing and discarding the core and any necessary annuli, the annulus members 41 are sized inserts through which the cable or pipe extends with the outer casing sleeves 47 being located and held in situ in the respective seatings 43,44.

The annul us members may be provided with a radial split (not shown) so that the annulus member when sized by removal of the core 45 and any annuli sleeves 46 can be pulled open for snapping overthe cable or pipe before seating the assembly into the seating. In the arrangement as shown in Figure 6, the annulus members 41 would be slid alongthecable or pipe from one end until the required position for seating in the half-block40.

twill be understood that this embodiment shows two annulus members 41 with respective seatings 43,44formed in the half-blocks. For some applications, it is envisaged that only one annulus member may be required and then there would be a single seating provided in each half-block.

It will also be understoodthatto provide a blanking lead-through block4', the complete annulus member41 with the core 45 is located in the seatings of the half-blocksto completely blank off that modular space.

The cable transit as aforedescribed is assembled from the individual components, and firstly the frame 1 is located in the structure with the runs of cables 3 extending through the opening 2 of the frame 1. The fitter is presumed to have the selection of modular lead-through blocks 4 as just described for each cable and a number of blanking blocks 5.

As depicted in Figure 1,the largest lead-through blocks 4c are used in the lower row, and firstly the lower half-blocks 40c are set against the bottom inner wall of the frame 1 and each respective annul us member 41 is sized to fitthe cable 3 and located or fitted onto the cable. The cable and the sized annulus members are then seated in the semi-cylindrical passageway 42 and in the respective seati ngs 43,44.

Then the upper half-block 40c is seated on top to form the lead-through block closing over the cable and the annulus members which are located in the seatings of the upper half-block. The stay plate 6 is then inserted in place on top of this lower row of blocks with the marginal flanged edges ofthe stay plate 6 riding over the side edges of the frame 1 to locate the stay plate 6 in a similar manner as forthe pressure plate 8. Preferably, the stay plate has a central web portion which is pierced or of mesh to prevent high rates of heattransferfrom one side to the other of the cable transit when installed.

Thefitterthenselectsthe next cables 3 to be located in the lead-through blocks 4b forthe next row and this row includes a solid blanking block 5.

The assembly using the annul us members sized for the cables 3 isasforthefirst row, and when the blocks 46 and block 5b are assembled another stay plate 6 is located over the row of blocks.

The third row of blocks 4a,fta and 5a is then assembled in a similar manner, and all ofthe cable runs are enclosed by the selected sized lead-through blocks and modular spaces are filled either by the solid blocks 5a or the blanking lead-through blocks 4'The lower portion oftheframe opening isfilled by the rows of blocks and stay plates 6.

Once this assembly has been completed by the fitter, it is then necessary to apply pressure to the assembled blocks and cables to clamp and seal the blocks together as well asto seal such sized lead-through blocks to the cable. In addition,the remainder ofthe opening in the frame 1 must be closed or filled. This next stage to complete the assembly is by the component parts ofthe compression and packer assembly as previously mentioned.

The pressure plate 8 is located overthethird row of blocks and seated overthe assembled array of blocks and cables. Due to the resilient nature of the blocks and the effect of the cables, pressure must be applied to the assembled blocks to compress the blocks around the cables to seal the lead-through blocks both around the cable and to clamp them together and againstthe side walls ofthe frame 1 and to the stay plates 6.

To applythis pressure,the compression bolt 33 is rotatedto bring the head 34into engagementwith the flat central portion 24 of the plate Sand on further rotation of the head 34 compressive forces are applied through the plate 8 to the assembled blocks.

Once the compressive forces are sufficient to leave a clearance space between the pressure plate 8 and the inner face ofthetop frame wall 29, the fitter can insertthe two outer compression blocks 9 and 11 in the clearance space clear of the compression bolt which only extends to the centre of the clearance space and does not interfere with the fitting ofthe two side blocks 9 and 11.

Following the insertion ofthetwo side compression blocks 9 and 11,the compression bolt 33 can be counter-rotated to return the bolt into the bore ofthe boss 31 leaving the central area overthe pressure plate free for insertion of the central wedge shaped compression block 10 between the two side blocks 9 and 11. The assembly of the rows of blocks and cables will continue to exert reactive forces on the pressure plate 8 tending to displace it towards the top wall of the frame, and thus tending to compress the blocks 9 and 11.To obviate the affect of these reactive forces, the limit pins 28 mounted in the compression blocks 9 and 11 restrict squeezing ofthe blocks Once the three compression blocks 9,10 and 11 are received within the clearance, the front support plate 18 can be engaged overthefree ends of each ofthe compressor studs 12,13 and 14 and the respective nuts 19,20 and 21 placed in threaded engagement.

The fitterthen tightens each of the nuts 19,20 and 21 to apply compressive forces to the compression blocks so that the three blocks are brought into wedge clamping engagementwith each other and brought into engagement with the support plate 18.

On tightening of the nuts, each ofthe compression blocks 9,10 and 11 is sequeezed so as to cause resilient displacement ofthe block material in a direction transverse to the axis of each compress stud thereby expanding the assembly both to fill the clearance opening between the pressure plate 8 and the frame 1 and to exert the required clamping pressure onto the assembly of blocks and cables beneath the pressure plate 8.

Accordingly, the compression and packer assembly 7 completes the filling ofthe opening 2 in the frame 1 whilst also applying the necessary forces to the assembled rows of blocks and cables to ensure thatwhole assembly is sealed together and securely located against displacement.

The forces applied to the assembled rows ofthe lead-through and blank blocks are sufficient to cause each lead-through block including the elements of the annulus members to be maintained in clamping and sealing engagement with the cable.

As will be understood, the fitting ofthe cable transit arises in various environments, and the cable transit may be installed as described in the vertical position, but it may be installed horizontally where safe retention and ease of assembly of the blocks and other component parts is required. In addition, the fitter may have to work in elevated positions n ladders or in confined positions where the number of blocks with existing transits is excessive with one blockfor each size cable. Thus, the cable transit of this invention provides many advantages overthe prior art systems.

The exemplary embodiments described are simplified for an understanding of this invention, and the numbers and relative dimensions ofthe blocks may be varied whilst maintaining the principles of modular sizes, and of course in known manner, more than one block mayfill a modular space, for instance four small blocks as shown in row a may fill a modular space in row c.

The resilient material of which the lead-through and blanking blocks as well as the compression blocks are made can be of any suitable material which is flame-resistant, fire-resistant, water-resistant and resistant to effects of rodent attack, ageing, and temperature variations.

Throughout this Description, reference has been made to cables as this is the commonest form of use of transits through bulkheads, partitions or the like.

However, the invented cable transit can be used and applied to pipes or conduits and the term "cable" is not intended to be a limitation to the application and use ofthe invention nor is the use of the term "cable" to be interpreted as a limitation to the scope ofthis invention.

Claims (10)

1. A lead-through transit for cables or pipes ofthe kind comprising a rectangular metal frame defining an opening through which the cables are to extend, a series of sets of modular blocks for assembly in rows within the frame opening, the blocks being adapted for su rrou nding each cable or for blanking off a modular space, and a compression and packer assembly for mounting the frame opening to clamp the assembled blocks together and around each cable with the compression and packer assembly completing filling oftheframe opening, and characterised in that the lead-through block comprises two complementary half-blocks and an annulus member for engagement within complementary semi-cylindrical seatings formed in the half-blocks, the annulus member comprising a cylindrical core having a plurality of annuli in the form of concentric annular sleeves of specific radial thickness nestedwithin each other on the core, the arrangement of the lead-through block being such that to provide a cylindrical lead-through passageway for a cable of specific diameter the core is removed from the centre of the annulustogether with any selected next encirciing sleeves until a sized passageway is formed through the annulus member thereby providing a sized insert for receiving the specific diameter cable therethrough and the sized annulus being inserted and engaged in the seatings ofthe half-biocks.

2. Atransit according to Claim 1 wherein the core and encirling annuli sleeves are connected to each other by shear webs or other fragile portions enabling partition of the sleeves and core from each other.

3. Atransit according to Claim 1 or Claim 2 wherein each half block has two seatings formed therein, each for seating a respective one of two annulus members, the seatings being spaced apart in the axial direction of the cable to extend therethrough.

4. Atransit according to any one of the preceding Claims wherein the annul us member is maintained intact and is seated in it's seatings of the half-blocks and provides a blanking block for use in a modular space.

5. Atransitaccording to to any one of the preceding Claims wherein the outermost annuli of the annulus member provides a casing sleeve of thickness greater than the inner concentric annuli sleeves.

6. Atransitaccordingto Claim 5wherein the inner diameter of the casing sleeve is substantially the same diameter as a passageway formed through the block and defined by lands extending on either side of the seating.

7. Atransit according to any one of the preceding claims wherein the annuli sleeves surrounding the core have a radial slittherethrough.

8. Atransit according to any one of the preceding Claims wherein the modular block is of square cross section.

9. Atransit according to any one of the preceding Claims wheren adjacent rows of modular blocks are separated and located by stayplates engaging the frame.

10. A lead-through transit substantially as herei nbefore described with reference to the exemplary embodiments shown in the accompanying drawings.