Patent Publication Number: US-7591196-B2

Title: Core splitters

Description:
This invention relates to core splitters. 
   Borehole core samples which have been drilled from rock are normally of elongated cylindrical shape. When these are examined, they are often require destructive testing. In order that an accurate record sample of the core is maintained, the core is usually split along diametral planes into two or more parts so that one can be examined and the other retained as a record sample. The cutting of the core in this way is an extremely difficult and inconvenient operation. The engagement of the cutting disc with the core, which is normally very hard, to effect the cutting operation is extremely noisy. Furthermore a significant amount of dust and cuttings are formed during the cutting operation. In practice it is very difficult to contain the dust so that an workplace and indeed the workman too is covered with dust. 
   According to one aspect of the invention there is provided a method cutting a borehole core sample using locating means for holding the core sample and a cutting device, comprising submerging the core sample in a liquid bath and then moving the cutting device relative to the core sample to cut the sample in the bath. 
   Preferably the locating means will be fixed and the cutting head will move relative thereto. 
   According to another aspect of the invention there is provided a core splitter comprising a trough in which the liquid bath will in use be contained, a core support device for holding a core in position during a cutting operation, which device is located within the trough, and a cutting head to which a cutter may be attached and which can be moved along the trough to cut the core along radial planes into two or more parts. The trough is preferably substantially watertight and the core support device is conveniently located at a position such that when the trough has an appropriate amount of water therein, the core will be below the level of the water. The cutting head preferably runs along linear bearing means located longitudinally above the trough. 
   The cutting head preferably comprises a rotatable cutting tool, preferably a cutting blade, that is driven directly by an electric motor, and a cowling within which the tool is contained. The cowling is preferably arranged so as to have its lower edges submerged within the bath. 
   A settling tank is preferably provided to receive cuttings from the water. This settling tank is preferably located below and at one end of the trough. A concentration tank is also conveniently provided as is means to deliver the sludge from the settling tank so that further settling can take place. 
   The core splitter preferably comprises means for moving the head along the length of the trough. Such means preferably comprises an elongated screw member which engages in a nut that is carried by the head and which, when rotated, moves the head. 
   According to another aspect of the invention there is provided a core holder in which the core is carried in the aforesaid core splitter during the aforesaid method, the core holder being of polygonal and preferably hexagonal section and dimensioned to hold the core firmly, the core holder having a slot at its upper end through which the cutter can enter the core holder to cut the core. At the lower end, the core holder is preferably provided with slots through which the cuttings and other detritus formed during the cutting operation can pass into the trough. The lower portion of the core holder is preferably shaped to correspond to the core support device so as to be firmly held in position thereby. 

   
     An embodiment of the invention will now be described by way of example with reference to the accompanying drawings. 
     In the drawings: 
       FIG. 1  is a side view of a core splitter of the invention showing the means for moving the head along the trough, 
       FIG. 2  is another side view of the core splitter showing different parts, 
       FIG. 3  is a perspective view of the bath member, 
       FIG. 4  is an enlarged transverse section of the core splitter, the section being taken on line  4 - 4  of  FIG. 1 , 
       FIG. 5  is an enlarged detail of  FIG. 4  showing the core during the cutting operation, 
       FIG. 6  is an enlarged detail of  FIG. 4  showing the cutter head and its supports. 
       FIG. 7  is an enlarged detail showing the support members for the core, and 
       FIGS. 8 and 9  are respectively a perspective view and a side view of a core holder for holding the core during the cutting operation. 
   

   Referring now to the drawings there is shown a core splitter  10  of the invention. 
   The core splitter  10  comprises a framework  100 , a cutter head  200  and a core support  300 . 
   The framework comprises an elongated rectangular base member  102  carried on feet  104  on the ground  106 . At the corners the base member  102  carries vertical members  108  on which is mounted a top portion  110 . The top portion  110  carries a robust longitudinally extending horizontal member  112  from the edges of which depend vertical plates  114  (best shown in  FIGS. 3 ,  4  and  6 ). On the inside lower parts of the plates  114  are bolted raceways  116  which constitute linear bearing means as will become apparent below. A low rim  118  is provided on the upper side of each raceway  116  near its inside edge. 
   The framework  100  carries a horizontal bath member  122 . The bath member  122  consists of two longitudinal walls  124  and  126  and two end walls  128  and  130 . A longitudinally extending inner wall  132  is located close to one side wall  124  to form therewith a narrow trough  134 . At the end of the trough  134  adjacent the end wall  130  is a substantially rectangular opening  136  below which is a frusto pyramidal settling tank  140  having a sump  141  at its lowest point. There is a transverse low wall  142  extending from the inner wall  132  to the wall  126  defining one end of the opening  136 . The settling tank  140  extends beyond this wall  142  and its inner portion is covered by a plate  144 . A closure  146  extends from the end of the plate  144  to a floor  148  on the side of the inner wall  132  opposite to the trough  134 . This floor  148  is a continuation of the floor  150  of the trough  134 . 
   A pipe  152  extends from the closure  146  over the floor  148  to the wall  132  near to the end wall  126  for the purpose which will be described. 
   The upper ends of the walls  124  and  132  have inwardly directed flanges  156  which lie over the trough  134  (best shown in  FIG. 5 ). A downwardly depending rim  158  is provided at the inner end of each flange  156 . 
   The core support  300  comprises two pairs  302  and  304  of robust square section solid support members located at about one metre apart within the trough  134  (as see in  FIG. 7 ). The support members of each pair are mounted in carrier plates  306  and  308  which are each supported on intermediate plates  310  and  321  and are secured to the floor  150  of the trough  134 . The members  302  and  304  are mounted on the carrier plates in such a way that they can move relative thereto transversely to the trough  134 . The carrier plates  306  and  308  are mounted on the intermediate plates  310  and  231  in such a way that they can be moved slightly transversely to the trough  134  to ensure that the members  302  and  304  are centrally located in the trough  134 . 
   The upper ends  312 . 1  and  312 . 2  of the members  302  and  304  are inclined to the vertical by 45°. They thus form a 90° seat  316  as will described more fully below. 
   A pair of aligned transverse bores  318  and  320  are formed in the support members  302 . 1  and  302 . 2 . A threaded adjustment bolt  322  passes through these bores  318  and  320  and is journalled in plumber blocks  324  mounted on the carrier plate. The ends of the bolt  322  extend beyond the plumber blocks  324  for the reasons that will be described. From its central part  326 , the bolt  322  is threaded in opposite directions and the bores  318  and  320  are complementarily threaded. Thus as the bolt  322  is rotated, the support members  302 . 1  and  302 . 2  are moved towards and away from one another. 
   A pulley  328  is provided on the projecting end  320  of the bolt  322  nearer the wall  124  and a similar pulley  332  is provided on the other projecting end  334  of the bolt  322 . A drive pulley  336  is carried by a shaft  338  journalled in the wall  124  and this is provided with a control wheel  340  outside the journal. A belt  342  joins that pulleys  332  and  324 . 
   The other pair of support members  304  are substantially identical to the members  320 . In this arrangement the adjustment bolt  346  extends beyond the plumber block nearer the inner wall  132 . A pulley  348  is provided on this extension. A belt  350  joins the pulleys  332  and  348  near the wall  132 . It will be seen therefore that by rotating the control wheel  340 , both adjustment bolts  322  and  346  will be rotated and the support members of each pair  302  and  304  will be moved transversely towards and apart from one another. 
   Bolted to the remote surfaces of each pair of support members is flat transverse plate  354  which will limit longitudinal movement of the core  360 . 
   In order to locate a core  360  accurately on the support members  302 ,  304 , it is placed in a carrier  362  (see  FIGS. 5 ,  8  and  9 ). The carrier  362  is a bent sheet steel member comprising a pair of lower surfaces  364  located at right angles to one another, a pair of vertical surfaces  366  and a pair of upper surfaces  368  which are at right angles to one another but which stop short of meeting each other to provide an opening or slot  370  running along its length. The vertical members  366  are spaced apart by a distance slightly greater than the diameter of the core  360 . Openings preferably in the form of slots  368  are provided in the lower portion of the carrier  362  through which the cuttings and other detritus formed during the cutting operation can pass into the trough 
   In use, the trough  134  is filled with water  372  to a level  374  slightly higher than the height of the core  360  when in the carrier and supported on the support members. The level  374  is slightly lower than the shaft  338  which passes through the wall  124 . 
   Placed above the opening  136  is a concentration tank  376 . A pump  378  driven by a motor  380  (not shown in  FIG. 2 ) is provided below the bath member  122 . It has an inlet pipe  382  and an outlet pipe  384 . The inlet pipe  382  enters and opens in the sump  141  of the settling container  140 . The outlet pipe  384  delivers into the concentration tank  376 . 
   The cutter head  200  is best shown in  FIGS. 2 ,  4  and  5 . The cutter head  200  comprises a drive motor  202  that is suspended from a cradle  204 . The cradle  204  consists of a robust horizontal plate  206  that is carried by a pair of robust side walls  208  which are located close to the ends of the raceways  116 . Each side wall  208  has respectively near its ends two pairs of shafts  210  and  212  located one above the other and projecting from its outer surface. These shafts  210  and  210  respectively carry upper and lower rollers  214  and  216 . The lower roller  216  runs on the lower surface of the adjacent raceway  116 . The upper roller  214  has a peripheral groove  218  in which the rim  118  is accommodated so as to support the roller  214  and with it the cradle  204  and so that the lateral movement of the cradle will be controlled. This arrangement permits the cradle  204  to move smoothly along the plate  206  as will be described below. 
   Mounted on the drive shaft  220  of the motor  202  is a tool carrier  222 . The carrier  222  has a central boss  223  which fits on the shaft  220 . The carrier  222  carries a cutting disc  224 . The diameter of the cutting disc  224  is such that its lower horizontal tangent will normally be below the lowest portion of the core  350  when mounted in the support members  302  and  304  and hence will have a substantial portion below the water level  374 . 
   The horizontal plate  206  has an extension  225  leading towards the cutting disc  224  and carrying a hollow cowling  226 . The cowling  226  comprises two parallel hexagonal side walls  228  and  230  equispaced about the cutting disc  224 . There is an opening in the side wall  230  through which the boss  223  of the tool carrier passes and a cylindrical projecting seal  231  engages the carrier to prevent water escaping from within the cowling  226 . The cowling  226  further comprises a vertical front wall  232  located near to the front-most portion of the disc  224  and rising to an inclined wall  233  connected to top wall  234 . A vertical rear wall  236  extends upwardly to about half the height of the cowling  226  and an inclined wall  238  joins it to the top wall  234 . The rear wall  236  is spaced from the rearmost portion of the disc  224  by a distance about three quarters of the diameter of the cutting disc  224 . The lower ends of the front and rear walls  232  and  236  respectively have openings  240  which correspond to and accommodate the upper part of the carrier  362  (See  FIG. 5 ). As can be seen from the drawings, the lower edges of the cowling are submerged within the bath. 
   An arrangement is provided for moving the cradle  204  along the plate  206 . This arrangement comprises a threaded elongated shaft  242  (see  FIG. 2 ) extending along the framework  100  at the same level as the raceways  116 . At the end of the framework  100  above the settling tank  140  there is a drive motor  244  connected to the shaft  242  through a reduction gear box  246 . The other end of the shaft  242  is rotatably carried in a journal  248  carried by a vertical plate  250  depending from the plate  116 . A transverse member  252  forming part of the cradle  204  incorporates a hollow threaded member or nut  254  through which the shaft  242  passes. As the shaft  242  is rotated, the cradle  204  is moved. 
   In use, the bath member  122  is provided with water  372  up to the level  374 . The core  360  is mounted in a carrier  362 . It is placed on the support members  302  and  304 . If necessary the support members ( 302 . 1  and  302 . 2  and  304 . 1  and  304 . 2 ) are moved apart by the control disc  340  so that the core  360  is at the appropriate height for cutting purposes. The cutter head  200  is located at the beginning of the traverse above the settling tank  140 . The motor  202  commences rotation. This causes the cutter disc  224  to rotate in a direction such that the part of the disc near the front face  232  of the cowling is moving downwardly. At the same time the motor  244  is also operated rotating the shaft  242  causing the cutter head  200  to move along the raceways  116 . The cutting disc will engage the core  360  and will cut through the core. 
   It will be seen that the cutting operation will take place below the level  374  of the water  372 . This will have the effect of significantly limiting the noise caused during the cutting operation. Furthermore all the cuttings and dust formed by the cutting operation will be contained within the water  372 . In addition, the cowling  226  will prevent water from splashing outside the apparatus. However the cutter disc  224  as it rotates forces the water towards the settling tank  140  where its level rises relative to the water level at the front end of the trough  134 . The water now runs down the pipe  152  to the front end of the trough  134 . At the same time the water carries the cuttings to the settling tank  140  so that it is removed from the water in the trough  134 . 
   Periodically the pump  378  will be actuated to draw the dust sludge from the settling tank  140  and to discharge it into the concentration tank  376 . The sludge settles in this tank and the excess clarified water spills over into the opening  136  to join the water used in the operation. On suitable occasions, the container  376  is removed to discharge the sludge at a suitable waste collection. 
   It will be appreciated that the core splitter can be used to split a core  360  into two semi-cylindrical samples. However by moving the support members apart and there by lowering the position of the core  360 , the cutting disc  224  can make cuts to about the centre of the core and the core can then be rotated so that a sample is produced which has a cross-section of a circular sector with an apex angle of 40°, 45° or any other angle as desired. 
   The invention is not limited to the precise constructional details hereinbefore described and illustrated in the drawings.