Maintenance, Operating & Service Manual
Contents
1. CDS R CDS 280R SD10 N100 Maintenance Operating amp service Manual 1 Introduction The Bulroc CDS280R Overburden System is a concentric drilling system designed to simultaneously case a hole through loose overburden conditions down into the solid bedrock This system has a multi stage cutting head to guarantee the drilled hole is straight with minimum deviation The independent segments around the periphery of the head give equal concentric cutting forces resulting in fast low torque drilling Since down time is very costly this system is designed to require the minimum amount of maintenance However when parts do eventually wear the construction of the system is such that the areas of the cutting head which experience most wear can be replaced independent of the slower wearing areas and so minimise operating costs List of contents GENERAL INTRODUCTION 1 USING THE CDS 280R 2 2 USING THE CDS 280R SYSTEM ema mometencresrosramencasmos B TT cr ass 3 O eee 3 A stes 4 HOW THE SYSTEM WORKS REFURBISHING WORN EQUIPMENT RING BIT amp THE SEGMENTS 8 WELDING THE DRIVER a TROUBLE SHOOTING HINTS AND TIPS 10 12 2 Using the CDS280R Drill Rigs Drill rigs on which the CDS280R is to be used should have a feed length at least one metre more than the longest casing This will allow sufficient clearance for any adapters or drive subs required by the system Dri2. regular intervals with the correct equipment not only improves component life but also improves production and reduced overall drilling costs e Buttons should be reground to their original shape when the wear flat is 1 3rd the diameter of the button If the button is cracked or chipped it should be ground back flush to the steel matrix It is possible to carry on drilling with a number of broken buttons if they are ground back in this way providing they are not affecting the gauge diameter or are not adjacent to each other since this would affect the smooth rotation of the bit After regrinding check the protrusion heights of the buttons If a button protrudes too far from the steel body it will cause premature failure of the button The side protection buttons should be ground back flush with the body The gauge buttons should be ground back until their protrusion height is their diameter To perform the task of regrinding correctly we recommend the use of a hand held grinder with gravity fed water supply necessary to cool the impregnated diamond grinding cups A combo type grinding cup of the approximate diameter will remove the surrounding steel matrix and reform the carbide button at the same time The Driver The shoulder on the driver where it contacts against the casing shoe will eventually wear This is quite normal and to be expected However when the drive shoulder does become worn to a taper shape it will begin to jam in
3. against the drive shoulder on the driver there should be between 12mm and 25mm clearance between the back faceof the segments and the front face of the casing shoe depending on the size of the system This distance will increase as the drive shoulder and or the casing shoe wears Make sure the segments swing from open to closed position freely by hand Use the diagram on page 3 to make sure the correct length of starter casing has been calculated When drilling commences use slow forward rotation If jamming occurs ease back on the feed force or lift the CDS and the casing until rotation starts again Initially the casing may rotate but after drilling down the casing 1 2 meters it will stop rotating Apply only light feed and reduced air pressure when setting the first casing and make sure the casing stays in line with the drill mast When drilling through soft materials sand clays etc frequently lift the CDS and the casing a little to ensure that it is loose and to flush out any debris from the casing When the CDS is in the hang position all available air will go to directly flushing the casing In sand and gravels it is often preferable to reduce air and feed pressure to a minimum In all ground conditions it is good practice to lift the casing frequently to make sure it is loose and to clear all debris from the casing 11 Hints and Tips continued e When drilling in sticky plastic clay the addition of water or even f
4. allow the system to be pulled back into the casing Once inside the air can be turned back on and the system should then be moved up and down inside the casing until the blockage is cleared At no time must the system be rotated whilst it is inside the casing as this will cause the segments to jam against the casing wall 12 Hints and Tips continued When the casing is clean the system should be fed back through the shoe using the reference point on the rod to indicate when it is through the shoe Once through the shoe the system can be rotated clockwise to open out the segments e Always re grind worn buttons Never do the Following e Penetrate too fast in loose ground Overfeeding will bury the CDS and block the casing with nowhere for the hammer air to exhaust hence stopping the hammer Always give the flushing air a chance to bail out the debris and keep the casing clear e Over rotate This will lead to premature button wear In rock or boulders rotation of the CDS280R should be between 12 to 15 rpm In loose ground conditions this can be increased by 50 e Apply weld to either the ring bit apart from a small tack weld at the start of the pin hole or the segments This can lead to cracking and button failure No warranty can be considered on these parts if there is any evidence of welding This page is left intentionally blank CDS R 2013 Bulroc UK Ltd All Rights Reserved Turnoaks Business Park Bur
5. are given in page 8 How the system works PR LT The Bulroc CDS 280R overburden system is designed to enable the operator to drill and simultaneously case a hole through loose overburden ground conditions down into solid rock See diagram 1 After reaching the required depth the segments can be moved into the closed position by pulling the system up against the casing shoe and counter rotating If the hole has reached solid rock at its required depth then the system can be closed by resting the system on the bottom of the hole and again counter rotating With the segments fully closed the system can now be retracted through the casing leaving a clean cased hole See diagram 2 Should it be necessary to drill on further into the solid rock the CDSR system can be detached from the Hammer and replaced with a conventional drill bit that can pass through the casing shoe See diagram 3 The Bulroc CDSR overburden system simultaneously cases the hole by means of a shoulder on the driver This shoulder locates against the top face of the casing shoe which is welded into the starter casing Since the casing does not rotate with the drill tubes the torsional loads are relatively low and so either left hand threaded or welded casing can be used O Refurbishing Worn Equipment The Ring bit and Segments The most frequent cause of button failure can be attributed to over drilling and incorrect button regrinding Regrinding at
6. e Pins as shown 2 Once the Pins are removed rotate the Ring Bit anti clockwise until it stops then pull the Ring forward to remove 3 The segments are now free to be withdrawn from their sockets 6 CDS280R Servicing continued At this point the segment bushes or sleeves can be examined These bushes are pressed into the driver to prevent wear whilst the segments are cutting and they are manufactured from hard wear resistant steel that should outlast many segment changes before they will require replacing Before re assembling the system it is important to check the condition of the slots in the driver where the ring bit lugs locate These slots may show some degree of wear and deformation and any signs of deformation must be removed using a small pencil grinder or similar to ensure correct location and drive of the ring bit This is particularly important if a NEW ring bit is being fitted to a WORN driver Re assembly Instructions To re assemble the system insert the new or re sharpened segments into their sockets and slide the new or refurbished drive ring onto the driver and rotate clockwise until it stops SELOC PIN SET RETAINING PIN Now insert a NEW retaining pin and gently drive home with the punch before finally inserting a new Seloc Pins Finally ensure a spot of tack weld is applied to secure the Pins in position so they cannot come out Recommendations for refurbishing worn components
7. e even and correctly form the 30 degree shoulder if the surface is uneven and the angle incorrect it will lead to premature wear and jamming 10 Hints and Tips Always Do the Following e Make sure the Driver will pass through all the lengths of casing intended for the job If the casing is to be welded extra clearance should be allowed for weld spots which may break through into the inside of the casing e f the casing is to be welded then the ends should be bevelled at an angle between 45 and 60 degrees To prevent weld breaking through and to help alignment a 3mm wide land should be left on each end face If the casing is the threaded type then it must be left hand Because of the cost of the thicker walled casing required to produce a thread it is normal practice to have threaded joints welded on to the end of thinner casing thus keeping the cost to a minimum If this is the case then great care must be taken to ensure the joints are true and concentric to the casing An out of line joint can result in either the system jamming inside the casing or the casing jamming in the hole As with welded casing the joints should have bevelled end faces to prevent weld breaking through into the inside of the casing e Check the casing shoes before the job starts The inside diameter of the shoe should be within the following tolerances CDS 280R Minimummm 281 5 283 Check the length of the casing shoes When in position
8. ley Close Chesterfield Derbyshire S40 2UB Tel 44 0 1246 544700 Fax 44 0 1246 544701 E mail info bulroc com website bulroc com CDS280R 100 26 7 13
9. ll Tubes Standard Hexagon Drive Drill rods used with the system may require sleeves fitting over their entire length This would be necessary to effectively reduce the annulus area between the drill pipe and the I D of the casing so as to increase the up hole velocity for efficient removal of the drill cuttings and also prevent blockages occurring inside the casing As a general guide the sleeve diameter should be 4 smaller than the bore of the casing but the exact size can be calculated by using the formula below A figure of 3000ft min 915m min should be used as a minimum for the required velocity Hammer In certain circumstances it may be necessary to sleeve the hammer This sleeve however should be a split bolt together type not welded The outer diameter of this sleeve should be the same as the diameter of the drill tube sleeves The formula below is for calculating the correct diameter of sleeves for the hammer and drill rods UP HOLE VELOCITY FORMULA METRIC VM Y CFM x 1305096 DM dm VM Velocity in m min Y Volume of air passed by Hammer at the selected pressure m3 min DM Diameter of casing bore squared in mm Dm Diameter of tube sleeve squared in mm UP HOLE VELOCITY FORMULA IMPERIAL VF Y CFM x 183 4 DI di VF Velocity in feet min Y Volume of air passed by Hammer at the selected pressure Ft min DI Diameter of casing bore squared in inches Di Diameter of tube slee
10. oaming agents in the hammer air may be necessary to maintain good flushing e When drilling through boulders or inclined rock faces the fact that this concentric system has a number of independently operating segments With a concentric system the independent segments only require a very small amount of movement to travel from the open to closed position this is somewhere in the region of 20 to 30 degrees rotation of the system Consequently if you attempt to hammer without rotation then the segments will swing back into the closed position causing the system to produce a socket in the rock that is only the diameter of the pilot bit So once rotation is resumed the segments cannot open back out as they are retained by the sides of the rock socket To prevent this occurring a concentric system should have its RPM increased and feed rate reduced once it starts to encounter boulders or inclined rock By doing this you guarantee that the segments remain in the open position even if their contact with the rock is intermittent The system should then be fed slowly into the boulder or rock face until continuous cutting can be heard At no time must the rotation be stopped whilst hammering is taking place If at any point the system starts to jam against the inclined face it must be immediately pulled back and then slowly fed forward back into the rock Once the system has formed a complete socket in the rock the speed and feed can be reduced back to the c
11. orrect rates suitable to the type of rock being drilled The segments on this concentric system should be much easier to move from open to closed position and consequently the most important consideration when using a concentric system is to maintain clockwise rotation throughout the entire drilling cycle The only time reverse rotation should be applied is when you wish to close the segments and at no time should the system be hammered without rotation as this will either allow the segments to vibrate back into a closed position or if this doesn t happen then the segments will form three sockets in the rock that could generate extremely high torque loads once rotation was re applied e When the casing has been set to the required depth and when drilling in sticky ground care must be taken to clean out the inside of the casing before extracting the drill string Water poured inside the casing repeatedly and flushed out will help the process On occasions it may be necessary to pull the CDS system back into the casing to flush out blockages To perform this task the system should be lifted into the hang position and rotated clockwise for 2 or 3 revolutions to ensure the bit face is clean The system should then be pulled back against the casing shoe and the air turned off At this point the rod should be marked to give a reference point for when the system is fed back through the shoe Reverse rotation for 1 revolution will then close the segments and
12. the casing shoe At this point it will be necessary to re form the drive shoulder back to its original 30 degree angle by welding up this area of the original shoulder It is important that the following procedures are strictly followed to avoid damage and cracking of the driver 9 Welding the driver Welding Procedures e The bit holder must be preheated to between 200 C and 250 C before any welding takes place e This temperature must be maintained throughout the welding process check temperature frequently using temp sticks e The weld must be applied in single runs around the shoulder area building it up to as near the original shape as possible Use 1mm CARBOFIL CRMO1 AWSAS 28ER 80S g_ or equivalent Bit Holder Bit Holder After Re machining e After welding the holder must be slow cooled This can be achieved by either burying the holder in a tank of vermiculite or similar or by wrapping it in an asbestos blanket This slow cooling is a very important part of the process Rapid cooling can cause cracking e Once the holder has returned to room temperature it should be turned on a lathe back to its original shape Dimensions for turning are given in the table on page 3 The correct shape is important to avoid rapid wear of the casing shoes and subsequent wear of the bit holder If a lathe is not available then a small hand grinder can be used to reform the drive shoulder Great care must be taken to get the surfac
13. ve squared in inches 3 Calculating lengths for starter casings 3m Casing 1635mm Starter Casing including Shoe Shoe Length 23mm 3m Rod 1575mm hammer length 407mm The above diagram shows the length of starter casing required when using standard CDS R equipment with the Bulroc HYPER 101 hammer If an alternative hammer is to be used the starter casing length can be calculated by either adding or subtracting the difference in effective length of the alternative hammer from that of the HYPER 101 hammer Casing O D 324mm 4 Casing Bore 305mm l Casing Shoe Dia 302mm Toe 300mm Casing Shoe Bore 283mm a Casing Shoe Size System parameters A CDS280R Parts List Ref Deseription Part Numbat ae A Te e System CDS280046R SD10 Complete System CDS280053R N100 First remove both the Retaining Pin 4 and Seloc Pins 3 by first 5 CDS280R Servicing The CDS 280R system is designed to require the minimum amount of service and maintenance However it is recommended that the system be stripped down every 500 metres and all the component parts checked for wear or damage Eventually the segments will need to be replaced and most likely the buttons on the ring bit will require re grinding At this time the following procedures must be followed grinding away the tack weld at the front of the pin hole Then using a punch from the opposite end of the Pin Hole Hammer out th
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