US3374521A

US3374521A - Tapping apparatus and method

Info

Publication number: US3374521A
Application number: US338751A
Authority: US
Inventors: Clarke Frederick
Original assignee: Tenneco Inc
Current assignee: Tenneco Inc
Priority date: 1964-01-20
Filing date: 1964-01-20
Publication date: 1968-03-26
Anticipated expiration: 1985-03-26

Description

5 Sheets-Sheet 1 F. CLARKE TAPPING APPARATUS AND METHOD freier/@ (/K/WJ) (/affe 735 INVENTOR March 26, 1968 Filed Jan. 2o, 1964 ATTORNEY March 26, 1968 F. CLARKE TAPPING APPARATUS AND METHOD 5 Sheets-Sheet 2 Filed Jan. 20, 1964 BY 5. M041 ATTORNEY March 26, 1968 F. CLARKE TAPPING APPARATUS AND METHOD 5 Sheets-Sheet 5 Filed Jan. 20, 1964 f/@a/e//C (MM/) (Var/re INVENTOR. 5 n W* flfOR/vfy March 26, 1968 F. CLARKE TAPPING APPARATUS AND METHOD 5 Sheets-Sheet Filed Jan. 20, 1964 i i l i wf) @0f/e INVENTOR.

fr@ der' AUTOR/V57 March ze, 196s F. CLARKE 3,374,521

TAPPING APPARATUS AND METHOD 4J l v United States Patent O 3,374,521 TAPMN G APARATUS AND METHD Frederick Clmire, Lafayette, La., assigner to Tenneco inc., Houston, Tex., a corporation of Delaware Filed Jan. 2t), 1954, Ser. No. 338,751 2t) lClaims. (Ci. 29--157) This invention relates to a tapping machine for cutting holes in pipelines, containers, and the like. More particularly, the invention relates to both a method and apparatus for performing a tapping operation on a container or a pipe, such as `a pipeline which may be carrying gas under pressure, wherein the tap is performed without substantial loss of the gas to the atmosphere. Further, one embodiment of this invention relates to an apparatus and method for utilizing uid pressure to operate drilling means for performing the tapping operation `and wherein the duid contained in the container being tapped may be utilized to provide a substantial part of the motive fluid to the fluid motor driving the cutting tool.

There are numerous problems associated with performing a tapping operation. Not only is it desirable to keep the loss of uid from the contm'ner being tapped to a minimum but it is necessary to be able to seal oif the opening made by the tapping operation after completion thereof by means of a vaive or the like. ln other instances it may be desirable to have this valve removed a considerable distance from the pipe being tapped, such as in the case of a submerged pipe, where it is desirable to have the valve situated above the ground or water surface. Hence, the tapping operation must in some instances be performed in a manner which will be characterized as a remote operation.

In addition, when advancing or feeding a drilling means into the pipe being tapped, it is also desirable to have a safety factor which will prevent breaking of the bit in oase it becomes lodged, which is not present with some mechanical means for advancing the drill-ing means.

Moreover, it is sometimes advantageous to perform a hot tapping operation such that the riser connected to the pipeiine may be connected on the side thereof and curved upwardly therefrom, thus permitting greater latitude in the positioning of the valve which controls the tap.

By having the valve controlling the tap positioned above water, there are many advantages derived therefrom, such (a) No extension drive is necessary to operate the valve;

(b) lt is easier to service the valve, such as providing the valve stem with packing from time t-o time;

(c) No valve seat lubricating lines leading upward from the valve to the surface are required.

The prior are is prolix with numerous examples of apparatus which have been developed for the purpose of accom-plishing certain tapping operations, none of which have been as successful as is the instant invention, and none of which have been successful in remote operation. For example, certain prior art apparatuses have been developed for cutting a coupon from a pipeline wherein a riser is connected to the pipeline and some anchor means is connected to the coupon itself, which anchor means is used in advancing the cutting means. With this apparatus the manner in which the valve can be set on the riser and the direction in which the tap may be made is limited. Other tapping apparatuses utilize drills which operate through risers provided with a packing. Here again there is a great limitation -on the direct-ion and method in which the tapping may be performed. Other prior art patents have utilized mechanical means for advancing the cutter toward the pipe to be tapped but are not easily controllable in situations where the cutting means becomes Patented Mar. 25, 1968 lodged, nor are they satisfactory when Ithe tapping operation must be performed remotely.

It is, therefore, an object of the present invention to provide an improv-ed method and `apparatus for performing a tapping operation on a container which may have a Huid under pressure contained therein and wherein that fluid may be used to perform a portion of the cutting operation.

It is another object of this invention to provide an improved apparatus for performing a tapping operation on a container, which apparatus may be remotely operated.

Another object of this invention is to provide an improved apparatus fo'r performing a tapping operation on a pipeline containing gas wherein the valve controlling the opening cut during the tapping operation may optionally be placed in a number of positions relative to the pipe.

At still further object of this invention is to provide a novel and improved drilling means for use -in performing la hot tap operation wherein the drilling means is provided with a novel anchor means for securing the drilling means and novel means for advancing the cutter into the pipe.

Yet another object of this invention is to provide an improved and novel apparatus for performing a hot tap wherein the aforesaid drilling means may be lowered and raised through an elongate riser.

These and other objects of the invention will be obvious to those skilled in the art by reference to the drawings and the descriptions herein.

`Briefly stated, this invention includes the method and apparatus for performing a tapping operation on a container which may have pressurized liuid contained therein such as a pipeline having pressurized gas therein.

An enclosed cham-ber is `formed adjacent to the pipeline and in communication with the external wall of the pipeline where the opening is to be cut. This is done by either welding or otherw-ise securing a tap riser, nipple, leader, side branch or the like to the pipe to be tapped. The riser is provided with a full opening valve at its upper end and means for sealably attaching a fluid tight housing thereto.

This iluid tight housing is provided with a drilling means positioned in drilling engagement with the Wall of the container -to be tapped.

In one embodiment this drill bit may have an annular cutter connected with a driving means and a pilot bit centrally positioned therein and extending below the cutting edge of the annular cut-ter.

Means are .provided for anchoring the drilling means in the riser and for advancing the drilling means toward the coupon or wall to be cut while the drilling means is actuated.

in one embodiment of this invention the motor is operated by duid under pressure provided m the enclosed chamber or iiuid tight housing. The cutting operation is started hy applying this pressurized fluid to the drill motor and continuing the drilling until the pilot bit punctures the pipe being tapped, thereby permitting the escape of pressurized iiuid from the pipe into the iiuid tight housing. This escaping fluid may then be applied to the motor to thereby complete the cutting operation.

The cutting means is then withdrawn from the riser, the valve on the riser is closed, and the iiuid tight housing removed, thus completing the tapping operation.

Reference to the drawings will further explain the invention wherein like numerals refer to like parts and in which: y

FlG. 1 is a side elevation view, partially schematic, showing the position of the apparatus as it may be seen just prior to or subsequent to the actual cutting operation.

FIG. 2 is a central sectional view of the upper portion of the apparatus showing a portion of the fluid tight chamber and the positioning of a reel therein.

FIG. 3 is a cross sectionalv view taken at line 3-3 of FIG.V 2 showing certain details of the reel, the conduit means for operating certain portions of the drilling means and certain features of the exhaust means of the invention.

- FIG. 4 is a side elevation view of the disassembled outer tubular shell of the drilling means showing the position of a slot therein.

FIG. 5 is a side elevation view in disassembled condition of the middle shell of the drilling means and Showing one embodiment of the lug which performs the function of limiting telescopic and circumferential movement of the outer shell relative to the middle shell.

FIG. 6 is an enlarged cross sectional view taken at line v6--6 of FIG. 2 showing the novel arrangement of the hose centralizing means.

FIG. 7 is an enlarged cross sectional View taken at line 7,-7 of FIG. 8A and showing certain details of the anchor-shoe means, the exhaust hose and the drilling means block.

n FIGS. 8A and 8B together form a side elevation View, partially in central vertical section, of the drilling means of the invention showing certain details of the arrangement of the cutting means, the motor, the anchor means, and associated elements.

FIGS. 9A and 9B form a central vertical sectional view, partially in elevation, of the drilling means of the apparatus taken at line 9 9 of FIG. 8.

Referring now to FIGS. 9A and 9B, the details of one embodiment of the drilling means, will now be discussed in detail. In that view the drilling means is centrally posiftioned in side branch or tap riser 11. Exhaust hose 12 is suspended in riser 11 and Apasses downward through hose guide assembly 13 to annular fitting 14, which in turnv is connected to fitting adapter 15, which is connected to and supports annular connector 16.

Annular connector 16 is provided with a side weldment or connector lug 17, which lug has a vtriangular shaped f4' vertical cross section and extends circumferentially about half way around connector 16. Connector lug 17 is provided with cable connector 18. Support cable 19 is attachedto and passes throughrconneetor 18, through annular connector 16, and thence upwardly through exhaust hose 12. The weight of the drilling means is supported by support cable 19 during raising and lowering thereof.

Hose guide` assembly 13 is an elongated member, arcuate in cross section and is provided with annular collar 26 at its upper end which encircles exhaust hose 12.

The bottom portion of guide assembly 13 is also provided withra lower collar 27 having an annular guide y assembly plate 28 attached to the bottom portion thereof.

Plate 28 is secured to piston control block 29 by bolts 30.

Piston control block 29 is provided with two separate piston means for actuating the anchor means of the invention and the drill-feeding means of the invention. Controlblock 29 is provided with a transverse annular opening therethrough, forming a cylinder, and in which is positioned for axial movement therein shoe pistons 31, thus forming an annular fluid chamber 32 therebetween. Piston control block 29 is also provided with a vertically extending uid channel 33 which communicates between fluid chamber 32 and shoe pressure conduit 34 extending downwardly through plate 28, whereby fluidized shoe pressure may be supplied to fluid chamber 32 to actuate duid pistons 31. v

Shoe pistons 31 are provided with annular O-rings 35 `toward their radially inward end. Each piston 31 has attached at its radially outward end an anchor means conveniently shown in the form of shoes 36, which extend vertically upward and downward from their connection to pistonspl and are arcuate in cross-section, each defining a segment of a circle. The outside surface of shoes 36 are optionally provided with layer 37 Qt fritisnsl. surface material for contacting and gripping the internal wall of riser 11 when shoes 36 are actuated or moved radiali outward to engagement with riser 11.

The lower portion of piston control block 29 is formed with a vertically and downwardly extending cylindrical opening therein, forming fluid chamber 41 in which drill pressure piston 42 is positioned for axial movement therein.

The lower end of piston control block 29 has a reduced portion 43 which is provided with external threads on which is threadably mounted torque transfer plate 44, which surrounds reduced portion 43 of piston block 29. Plate 44 is secured on its lower'side to the end of a tubular middle torsion hold shell 45, the operation of which will be explained hereinafter.

Piston control block 29 also extends downwardly through plate 44, which extension is tubular in shape and Vis indicated as piston control tube 51, which forms the lower end of cylindrical uid chamber 41.

Drill pressure piston 42 is provided with `O-ring seals 52 near its upper end and is attached to annular piston extension 53 at its lower end. Piston 42 yis shown in the retracted position in FIGS. 9A and 9B. Piston extension 53 is of a slightly larger diameter than piston 42, hence f forming anfupwardly facing shoulder which engages the piston extension 53 is also secured to plate 56 by boltsr 57. 'Plate 56 is secu-red, as by welding, to the top end of another tubular member extending downwardly therefrom and conveniently shown inthe form of inner drill force transfer shell 58. The lower end of inner shell 58 is connected by radially extending screws 59 to annular motor drill press adapter ring *60, which has a reduced upper portion which lits inside of inner shell 58.

A uid pressure motor of a type to be described hereinafter is mounted in housing 66, which is secured to the upper portion of adapter ring 60 by bol-ts 67 which extend downwardly and connect to gear reduction box 68, which likewise is -a tubular member and has an enlarged lower portion forming a lower gear housing 69.

For purposes of convenience, housing 66, adapter ring 60, gear box 68, and lower gear housing 69 will generally be referred to as the motor housing. The drive shaft (not shown) of the motor positioned in housing 66 isV rotatably driven through gears (not shown) provided in gear reduction box '68 and lower housing V69, such that drive shaft connection 70, which extends axially out 'from the lower end of lower housing 69, is rotated thereby.

Drive shaft connection 70 is'attached to a downwardly extending cutter adapter socket 7'1 for rotation therewith. Positioned inside of and extending out yof the fbottom opening of socket 71 is a cutter adapter 72, which is held therein by adapter tie pin 65. Adapter 72 has annular ange 73 extending radially outward therefrom, and is lalso provided with an axial and downwardly extending opening inV which is threadably secured cutter pilot bit 74 having small spring loaded detent balls 75 projecting from the outside surface thereof and near the lower end. Pilot bit 74 is slotted on the lower end to allow passage of fluid and is designed for cutting through steel pipe and the like.

Surrounding pilot bit 74 and abutting against the lower end of adapter 72 is an annular cutter 76 having teeth 77 forming the cutter surface thereof. Teeth 77 may -be of adapter 72. Thus it may be said that pilot bit 74 extends downwardly from the cutting surface of annular cutter 7d.

Referring now to the lower end of lower gear housing 59, it will be observed that an annular ring having an axial opening therethrough is attached thereto, which ring will be referred to as outer shell base 80.

Outer shell ibase d is of a larger diameter than lower gear Ahousing 69 and hence forms an upwardly facing shoulder to which is secu-red, as by welding, lan upwardly extending tubular outer shell 96 which surrounds gear reduction box 63 adapter ring 69 and middle shell 45.

Referring now to FlG. 9B, the lower end of housing 69, and hence outer shell base Sil, are centrally positioned inside of 'tap riser 11 by centralizer means which includes hat ring shaped bottom centralizer 84, the outside circumferential surface of which is adapted for sliding engagement with the inner surface of riser 11. Centralizer y8d is secured to housing 6g by means of screws which pass therethrough and engage in ring shaped annular plate 83, which is spaced apart from base Sil by a plurality of ring shaped spacer plates 8.2, with a plurality of bolts 31 passing upwardly therethrough, the upper ends of which are threaded into housing 69. Thus, the lower end of housing 69 and base `80 are centrally or co-axially aligne-d in riser 11. This facilitates the holding of pilot bit 74 and annular cutter 76 centrally in riser 11 whereby a uniform coupon may be cut in the pipe being tapped.

ln operating the tool, it is apparent that since inner shell '53 is xedly secured to outer shell 99 through the motor housing, the two will move together, both axially and circume-rentially. Hence, when cutter pilot bit 74 and annular cutter 76 are rotated by the motor and the cutting surfaces are engaged, counter torque will be exerted on inner shell 5S and outer shell To prevent these elements from rotating or moving circumferentially with respect to middle shell 45, stop means are provided for preventing such rotation. Moreover, since inner shell 53 and outer shell 9b will likewise move teles-copically with respect to middle shell d5 `when piston d?. is actuated, means are also provided for limiting this telescopic movement. The foregoing means take the form of travel limit stop and torque 4transfer lug 91 secured to middle shell de', as ibest seen in FIG. 5. Near the lower end of middle shell i5 there is provided an annular recess 92 thereabout. Lug 91 is provided with a transverse ilange, forming an inverted T-shaped design, as lseen in FIG. 5, wherein ears 93 extend Vtransversely therefrom. Ears 93 are formed to be llush `with the outside cylindrical surface of shell and are secured in annular recess 92 by mounting screws 94. However, -lug 91 proiects radially outwardly from the outside cylindrical surface of outside middle shell 4S and engages in the inverted T-shaped slot 95 of outer shell 91), which slot is best shown in FIG. 4. The enlarged end or" T slot 9S is merely for convenience in inserting lug 9i therethrough so that ears 93 will clear during assembly. The relative circumferential movement and the amount or telescopic movement .is thus limited by lug 91.

Referring again to FIG. 9B, housing 66 is connected at its upper end with connector 1G55 and exhaust tubing 95, the purpose of which is to exhaust motive uid from the motor positioned in housing 66 after 'the duid has passed through the motor. lt is to be understood that there is an appropriate inlet port (not shown) in the motor such that motive lluid present vin riser 11 will operate the motor. Pressurized fluid contained within riser 11 has ready access to the inlet port of the motor and is exhausted therefrom by exhaust tubing 105.

Referring now t-o lFlG. 8B, it will be observed that exhaust tubing 106 curves radially outward and through openings provided in plate `56 and ange 54 of piston ex- `tension 53 and also through a longitudinal slot 167 provided in the wall of middle shell 45. Exhaust tubing 106 5 then extends upwardly and into a downwardly opening exhaust cylinder 163. Cylinder 16S passes through an opening in middle shell plate 44 and is secured thereto by threaded connector sleeve 139 lwith exhaust cylinder 163 projecting upward there-above.

Exhaust tube 196 terminates just above connector sleeve N9 where an exhaust tubing piston head 11d is connected thereto, which in turn is provided with O-ring seal 111. Thus during the telescopic movement of outer shell 9i) and inner shell 5S relative to middle shell d5, piston head 1li) moves back and forth inside exhaust cylinder 168.

The top end of exhaust cylinder 198 connects with connector 1.6, which communicates with exhaust hose 12. The foregoing generally explains one embodiment of the cutting means of the invention.

Referring now to FlGS. 7 and 8A, the operation of the anchor means of the drilling means will now be explained in detail. As previously explained, shoe pistons 31 are mounted for transverse movement in piston control block 29. Control block 29 is also provided with four transverse shoe guide channels 118, as best seen in FlG. 8A, with two channels being on either side of block 29 and spaced above and below piston 31.

Each shoe 36 has welded thereto two snoe guides 119, which guides are arranged to slide longitudinally in shoe guide channels 118. The purpose of shoe guides 119 is to prevent shoes 3d from twisting out of vertical alignment. Hence, each shoe has one shoe guide 119 connected for movement in one of the upper shoe guide channels 118 and another shoe guide 119 mounted for movement in the lower shoe guide channel 118 on the opposite side of shoe pistons 3l.

ln order to assure that both shoes 36 move radially outward in equal manner there is provided an equalizer mechanism in the form of shoe equalizer guide rod 129 which is threaded into the side of and extends radially outward from control block Z9 at a point above upper guide channels 118. Guide rod 12d is provided with a T-shaped guide block 121, which is adapted to slide radially inward and outward thereon. Each of the shoes 36 is provided with a shoe bracket H2, which is positioned in the same general transverse plane as guide rod 12? and which project radially inward from the shoes. A pair of equalizer arms 123 are connected between shoe brackets 22. and guide block 121 by pins 124. Hence, as shoes 36 are expanded radially outward, guide block 121 is pulled radially inward, insuring that both shoes move equally and uniformly outward and inward.

Means are also provided for supplying a pressurized iluid to operate drill pressure piston d2 and shoe pistons 31. Referring again to FlGS. 7 and SA, it will be observed that there are three identical connectors (one of which is designated as connector 13) emerging from and pointing downwardly from connector lug 17 on connector ltd. As explained earlier, connector 13 is attached to support cable l; another one of these connectors has drill pressure tubing 123 connected to and passing therethrough, which tubing communicates with upper connector 129 of a tubular drill press oil reservoir 13u mounted by upper and lower brackets 13l to hose guide assembly 13. At its upper end reservoir 130 is provided with plug 132 for filling reservoir 13) with oil or other liquid and the lower end of reservoir 13d is provided with lower connector 133 and connecting line 134, which leads downward to control tubing connector having xed orifice 136 leading into uid chamber di. The purpose of lixed orifice 136 is to prevent the rapid movement of piston 42 downward when vertical pressure is relieved on the drilling bit, upon complete penetration of pilot bit. Fluid to chamber 41 is supplied via oil reservoir 13) whenever pressure is supplied thereon through drill press tubing 12d which connects to a flexible conduit extending upwardly inside of exhaust hose 12.

Means are also provided to supply pressurized fluid to fluid chamber 32, to thereby operate shoe pistons 31, which `means arein the form of another conduit or flexible tube and connects to that connector supplying the shoe pressure fluid and connects to the upper end of shoe pressure conduit 34, as seen in FIGS. 8A and 9A. Hence, fluid pressure applied through the conduit in exhaust hose 12 and through shoe pressure tubing 140 to shoe pressure conduit 34 enters iuid channel 33 and fluid chamber 32 to force shoes 36 radially outward and to thereby releasably anchor the drilling means in a fixed relationship with riser 11. The foregoing generally describes the drilling means portion of the invention.

Referring now to FGS. 1 and 2, the means for raising and lowering the drilling means in riser 11 will be explained in greater detail. An elongate fluid tight housing adapted for securing to the top end of riser 11 is provided and is best shown in FIG. l. Housing nipple pipe 143 is Van elongate member forming a generally elongate chamber. The lower end of pipe 143 is provided with an outwardly expanding portion terminating in ange 144 which is adapted to be engaged in a sealing relationship with the I top flange of full opening riser valve 145 by means of bolts and a gasket or the like.

The upper end of pipe 143 may be formed with a reduced area 146 (oran increasing area, or neither, depending on size of the housing nipple), and an outwardly ar ing portion which terminates in top ange 147. Top flange 147 is arranged to be secured to a drum access flange 148 on the bottom of annular access fitting 149. It is to be understood that flange 147 and access ange 148 are held together in a fluid tight seal by bolts and a gasket or other conventional means. Mounted inside of access flange 148 and extending upwardly inside of access fitting 149 are four flat members or legs G which support a hose centralizer assembly generally designated by the numeral 151. Legs 15) are secured at their lower ends to the inside surface of access flange 148 by leg bolts 142.

Hose centralizer assembly 151 is comprised of base plate 152, as best seen in FIG. 6. Base plate 152 is generally square in plane View, having the corners thereof clipped and is formed in two parts, which parts are held together at adjacent edges 153 by screw and bracket means (not shown) on the underside thereof. An opening is provided through base plate 152, generally in the form of a cross. This cross-shaped pattern permits the mounting of four roller brackets 154, which are generally V- shaped in cross-section and extend upwardly a short distance from base plate 152 and thereby provide a mount-` ing for guide rollers 155, which are mounted on roller pins 156, which pins pass through brackets 154. Hence, during raising and lowering of the drilling means, exhaust hose 12 will pass through centralizer assembly 151 and thereby be centrally positioned in pipe 143.

Referring now to FIG. 2, the upper portion of the uid tight housing of the apparatus is shown therein. Annul-ar access fitting 149, previously described, is welded or otherwise secured to the lower side of a large tubular member in the form of drum 160. On each end of drum 160 an annular, dome-shaped drum end cap 161 is welded or otherwise secured thereto. Each 4drum end cap 161 has an annular opening therethrough, which opening is surrounded by end-plate 162 and in which seal bearing ring 163 is tted. Inside of seal-bearing ring 163, annular seal bearing 164 is inserted, having appropriate packing in the form of O-ring 159 therebetween. Reel shaft 16S is an elongated tubular member which passes through the iiuid tight chamber and extends outside both ends of the housing and through seal bearings 164, each of which is provided with a pair of seals in the form of O-rings 158 which contact the outside surface of reel shaft 165. The right end of reel shaft 165, as viewed in FIG. 2, is provided with stop ring 166 and hand wheel 167, which wheel is secured to reel shaft 165 by hub bolt 168. The

Vstop'ring 169. Hence reel 165 may be turned by turning on hand wheel 167 and oscillated back and forth by pushing and pulling on hand wheel 167.

Near the central portion of reel shaft there is mounted an annular reel hub 172 held in position by two spaced apart reel

flanges

173 and 174. Thus, there is formed a reel on which the exhaust tube of the invention may be wound and supported thereby. Alternately, reel anges 173 and 174 may be welded to reel shaft 165, or preferably, bolted thereto, as shown in FIG. 3, to facilitate disassembly of the apparatus. There, ange 174-is shown as having a centrally positioned scalloped opening therethrough and is secured to reel shaft 165 by bolts 213 passing through lugs 212 attached to reel shaft'165. This arrangement permits disassembly of the apparatus to allow removal of reel shaft 165 from the housing.

The exhaust hose (not shown in FIG. 2) is secured to a T and connecting nippl 175. Nipple 175 passes through ange 174 and connects to exhaust elbow 176, best seen in FIG. 3. Elbow 176 has an annular flange 177 which is secured to reel flange 174 by flange bolts 178.

The lower end of elbow 176, as seen in FIG. 3, is connected to coupling 179, lby means of nipple 170'which coupling in turn is connected to inside exhaust elbow 180 by means of another nipple 171; exhaust elbow 186 being positioned inside of and extending radially outV of reel shaft'165. Hence, the exhaust hose 12, shown in outline form in FIGpS, communicates through connector 181,

Vadapter182, connection elbow 133, exhaust T 184,

through nipple 175, elbow 176, nipple 170, coupling 179, nipple 171, to inside exhaust elbow 180.

Inside exhaust elbow 180 then connects to exhaust pipe 185,' which leads out the end of reel shaft 165, as best seen in FIG. 2. The end of exhaust pipe is connected to T 186, which communicates with nipple 187, to which a somewhat similar pattern of movement as the aforedescribed exhaust channel.

Referring to FIG. 3, these conduits emerge from exhaust ellbow 176 through pressure seal tube ttings 157 and are shown as drill pressure tubing and shoe pressure tubing 196, which connect with identical and smaller elbows 197 inside of reel shaft 165. Inside elbows 197 are then connected with a pair of pipe conduits 198, which lead out the end of reel shaft 165, as best seen in FIG. 2. The ends of pipe conduits 198 are provided with appropriate coupling means, the purpose of which will be explained hereinafter.

Thus, it may be seen that when reel shaft 165 is rotated, exhaust hose 12 is wound either on or off of reel hub 172 with exhaust hose 12,'passing up and down through hose centralizer assembly 151. By oscillating reel'shaft 165 back .and forth manually, hose 12 may be wound uniformly onto reel hub 172. Thus, no matter whether the exhaust hose is rolled out a short distance or a long distance, exhaust hose 12 and the tubing supplying uid pressure to the piston means in piston control block 29 will still communicate with controls located outside of the uid tight chamber. Furthermore, the support cable 19, which also passes up through exhaust hose 12 and which supports the drilling means, also terminates at elbow 176 where it is secured by connector 199.

Referring again to FIG. 2, the top part of the uid tight chamber is provided with lifting eye 201 which is secured to top part of drum 160 and is for raising and lowering the apparatus. Means are also provided for supplying a fluid pressure to the uid tight chamberinthefform of needle valve 2%2, which communicates with the inside of drum 169. The other side of valve 202 communicates through inlet checn valve 263 and thence to tube 2de, which leads to an appropriate supply of pressurized fluid, such as propane, for initially pressurizing the liuid tight chamber. Check valve 2%3 is set so as to prevent bach pressure inside the fluid tight chamber from backing up through tube 204.

Also communicating with the fluid tight chamber is another valve means shown as needle valve Ztl, which is connected to T 266, which is secured to drum i619 by coupling 207. The top end of needle valve 255 communicates to drum relief valve 263. T 206 also connects with panel drum pressure indicating tube 269, which leads to the panel control, as will be explained hereinafter.

Referring to FIG. 3, an internal relief valve in the form of check valve 2l@ is connected to one end of exhaust T 184. The purpose of check valve 21?` is to maintain the proper pressure differential between the huid chamber and inside of exhaust hose l2. Hence, if the pressure differential exceeds a specified level, check valve 2lb will be open to thereby prevent the collapse of exhaust hose l2. Such a sitaution might occur, for example, if the fluid motor, with which exhaust hose l2 cornmunicates, should become plugged.

Referring now to FIG. l, the hookup of the apparatus during operation will be described. Fluid pressure is supplied in the form of propane from bottles 2l? which supply propane through tube Ehi., through inlet check valve 2G31, through needle valve f2, and into drum i653. Means for controlling the operation of the various fluid pressures are provided in the form of control panel board 21S, which has several gauges. Brum pressure gauge 2@ cornrnunicates with the drum loi? via panel drum control tube 299 and indicates the drum pressure or the pressure inside of the fluid tight housing. Exhaust pressure gauge 22d communicates with exhaust pressure control valve SS via panel exhaust pressure indicating hose 239 and measures the exhaust pressure.

Another pressurized fluid supply in the form of nitrogen supply bottle 2.21 is connected by tube 222 to control supply gauge 223 which indicates the amount of pressure coming from nitrogen bottle 221. Tube 2.22 communicates with tube 2241 which leads to shoe pressure gauge 225 which indicates the pressure being supplied to actuate shoe pistons 3l in the drilling means. rr'ube 224 also communicates with shoe feed tube 225 and shoe vent 227. By operating the feed and bleed controls just beneath shoe gauge 225, the amount of pressure supplied to shoe feed tube 2213 can be controlled. Shoe feed tube 22e is connected with the shoe feed pipe conduit 1% which extends out the end of shaft 165'.

Nitrogen supply tube 222 also communicates with tube 228, which leads to drill gauge 22,9, which indicates the pressure bei .g applied to fluid chamber di which actuates drill pressure piston 42 in the drilling means. This pressure is similarly controlled by feed and bleed controls such that ressure from tube may be diverted to either drill feed tube Z3@ or drill vent 23l. Drill feed tube 234i likewise connects with the drill feed pipe conduit 2198 leading into the end of reel shaft E45.

In order to observe the operation of portions of the tool, drum lrr is provided with a plurality of site glass housings 234. Also, near the bottom of housing nipple pipe M3, there is also provided another site glass housing 234.

In performing the hot tapping operation, riser il is welded or otherwise secured to pipe 23S, which pipe may be a pipeline containing pressurized gas or other fluid. Riser ll can be of any desired lenffth, thus permitting a remote tapping operation. Riser 1l has an upper flange 236, which is secured to full opening valve 143 in a fluid tight relationship.

in operation of the tool, the housing, which includes drum 169 and housing nipple pipe f4.3, is lifted by lifting eye 2M into the position as shown in FIG. 1 and flange M4 is then secured to the `top flange of full opening valve 3.45. The drilling means shown in outline form inside of housing nipple pipe 143 will have previously been assembled and held therein by exhaust hose l2 which is wound onto reel hub 172 and held there by holding or otherwise preventing the turning of hand wheel 167.

After flange ldd is secured to valve 145 by bolts or other means in a uid tight seal, the propane supply is then connected to tube Zilli, which leads to drum ld. Exhaust valve 19@ and needle valve 2&5 are closed. Needle valve 202, which controls the propane supply, is opened, thereby providing lluid pressure in the form of pressurized propane to the enclosed chamber formed by drum 166 and housing nipple pipe lil?) and riser l1. The drum pressure at this point may conveniently be approximately p.s.i. at 60 degrees F. The drum pressure will overcome the pressure in fluid chamber 4l and then cause drill pressure piston 4Z to retract, which retracted position can be checked by viewing the relative axial position of Outer shell 9b and middle shell 45 through sight glass 234, at which point the drilling means is lowered into riser ll by turning on hand wheel 167. The drilling means is lowered until the pilot bit 74 engages the wall of pipe 23S, with some slack being left in exhaust hose 12.

Drill feed tube 23d is then connected to the appropriate pipe conduit ILQS leading into the end of reel shaft E65 and shoe feed tube 22d is similarly connected. ln addition, exhaust pressure indicating hose 189 is connected to valve 183. The valves on panel board Zl controlling shoe vent 227 and drill vent 231 will be open. The valve controlling the pressure to supply gauge 223 will be closed, as will be the valve controlling the feed to shoe feed tube 22e and drill feed tube 2.30. The valve on nitrogen supply bottle 221 is then opened, thereby providing a nitrogen supply to the control panel.

At this point, nitrogen pressure can be directed to shoe feed tube 22e by closing shoe vent 227 `and opening the shoe feed valve. Pressure is allowed to build up on shoe feed tube 226 to approximately 5G p.s.i. above the pressure inside of the fluid tight housing of the tool (drum pressure). Thus, shoe pistons 3l will be forced radially outward, thereby releasably anchoring the drilling means in riser l1.

Exhaust valve 19t) is controllably opened, thereby permitting the escape of gas from exhaust pipe l until the pressure differential between the fluid tight housing (drum) and the exhaust is approximately 4() p.s.i. and the fluid motor in the drilling means is rotating the cutting means at approximately 40 to 45 r.p.m. lt is this pressure differential which controls the rate of rotation of the fluid motor. As explained earlier, the fluid motor is positioned inside of housing 65. ln one form of the invention, the motor is a positive displacement 5 cylinder axial piston air motor. There is a gear reduction of approximately 44 to 1 between the motor and the drill bit or cutting means. The motor thus causes pilot bit '74 and annular cutter 76 to rotate.

The feed valve controlling pressure to drill feed tube 23@ is then opened, thereby supplying pressurized nitrogen to the top part of oil reservoir 13%, which forces oil into fluid chamber 4l, thus actuating or feeding piston 42 downward and advancing the cutting means against pipe 235. When the pressure on drill feed tube 23h equals the pressure inside of drum lbf), the weight of the lower portion of the tool or the drilling means will be the only pressure applied to the drilling bit. By allowing the drilling means to operate for a short period under these conditions, safety checks and the like may be made.

The drill pressure on drill feed tube 230 is then slowly increased until `a pressure of approximately 400 p.s.i. is reached. rIlle motor is continuously operated, maintaining a drill bit speed of approximately 40 r.p.m. until pilot bit l74 initially punctures the wall of `pipe 235. This initial 'penetration by pilot bit 74 will be signalled 'by an increase Vin drumV pressure inside drum 161i and by the escape of gas from relief valve 208, which may be set at about 125 p.s.i., since line pressure or pressure inside the pipe being tapped will generally be much higher. n

At this point exhaust valve 1% is closed, thereby stopping the operation of the motor. Needle valves 295 and 262 will also be closed. Y

The pressure inside drum 160 is then allowed to equalize with the pressure inside of pipe 235, which pressure will 'be referred to as line pressure. Pressure is then Vrelieved on shoe feed tube 226, `allowing shoes 3e to retract or release from an anchoring position, with the weight of the drilling means then being supported by pipe 235. Pressure is then re-applied to shoe feed tube 226 until there is a shoe pressure of approximately 12 p.s.i.

applied to the contact surfaces of shoes 36 against inside v with the drilling `continuing until pilot bit 74 completely penetrates pipe 235.

At this point exhaust valve 194i will be closed again.

Shoe pressure will once again be relieved as will drill pressure, to allow the shoes 36 and piston 42 to retract.

Annular cutter 76'will then 'be engaging the coupon to be Y cut 'from pipe 235. Shoe pressure is then re-set at about 12 p.s.i. on the contact surfaces of shoes 36 against inside wall of riser 11 and exhaust valve 19t? is again controllably opened until the motor is turning annular cutter 76 at approximately 32 rpm., at which point the differential between drum pressure and exhaust pressure may be approximately 100'p.s.i. Drill pressure is then increased on drill feed tube 230 until a pressure differential of 125 to 150 p.s.i. is reached. The cutting operation is continued so long as the motor shows notendency of stalling and until the coupon is cut from pipe 235. if the motor has ya-tendency to stall due to hanging up of cutter 76, exhaust valve 199 may be closed and the trouble inspected and the bit retracted by relieving the drill pressure and by permitting the motor to run with reduced drill pressure thereagainst.

Complete penetration by cutter 76 will be indicated by a drop in drill pressure. At this point exhaust valve 190 is closed and pressure is taken olf of shoe feed tube 226 and drill feed tube 239. Shoe feed tube 226 and drill feed tube 23) are then disconnected from their connections at the end of reel shaft 165 and exhaust pressure indicating hose 189 is disconnected from control valve 18,8, after that valve is closed. The drilling means of the apparatus is then raised in riser 11 by turning on hand wheel 167, with care being taken to uniformly roll exhaust hose 12 on to reel hub 172 by sliding reel shaft 165 back and forth. v

The coupon cut from pipe 235 will be retained on .pilot bit 74 by detent balls 75. When the coupon has cleared valve 145, that valve may be closed. Pressure may then be relieved on drum 160, and housing nipple pipe 1.43V may then be removed from the top of valve 145, thus completing the tapping operation.V

There is thus provided a novelV and improved method and apparatus for performing ra tapping operation, wherein the iluid contained in the container being tapped can 'be use-d to perform a substantial part of the cutting operation. The apparatus may be operated remotely, as by passing down through a long riser that has 'been attached to the pipe 'being tapped.

Since the exhaust hose and the means -for supporting vlthe drilling means areexible, the riser through which the drilling means isY lowered may be attached to one side of the pipe and thence curve upwardly, permitting the valve closing the riser to be optionally positioned in a number of positions relative to the pipe being tapped.

The invention teaches the use of a novel releasable anchor means for holding the drilling means, which anchor means can be released and re-set from timeto time as the cutting means advances. Moreover, the cutting means is advanced into the coupon by a uid pressure actuated feeding means which is easily controllable and which acts as a safety factor by indicating a 'build up of pressure if the cutting means :becomes lodged.

There are, of course, many alternatives of the foregoing apparatus which Willstill vfall within the scope of the invention. For example, support cable19 could be a exible semi-rigid member such that when hose 12 is unrolled from the reel, the drilling means of the tool would be forced along in the riser or side branch by the semirigid member acting as -a ramirod. Thus, the tool could be used in a horizontal side branch, without relying on gravity to advance the drilling means into the side branch.

Other anchor means 4could lbe used, as for example, only one shoe could 'be used, with the other side of piston control block 2-9 'being supported Eby a rigid member.

lso, it is to be understood that when various parts are described as being connected to each other, this connection may be either a mechanical connection or an operational connection.

lt is to ybe understood that the apparatus could be used v to perform a tapping operation on a container which did not contain a pressurized iluid. After initial puncturing of the container, drilling could be continued as soon as pressure equalized, thus preventing the escape of gas to the atmosphere and still keeping the uid tight housing pressurized to operate the drilling means.

Other modilications may be rnade in the invention as particularly described without departing from the scope of the invention. Accordingly, the foregoing description is to be construed illustratively only and is not to be construed as a limitation upon the invention as defined in the following claims.

What is claimed is:

1. The method of performing a hot tapping operation on a container having a first fluid under pressure contained therein, comprising the steps of: forming an enclosed chamber adjacent to and in communication with a portion of the external wall of said container, positioning a uid pressure actuated drilling means with a drill bit within said chamber and holding said advancing said bit into said wall during operation of Y said drilling means, continuing the application of said second fluid until said bit initially penetrates said wall, to thereby permit the escape of said first uid from said container into said chamber, applying said Iirst fluid to operate said drilling means to complete the cutting of an opening into said container. f i 2. The method as claimed in claim 1 comprising the additional steps oi:

withdrawing said drilling means to a portion of said chamber which is removed from said wall, and sealing of that portion of said chamber from which said drilling means was removed. y 3. The method of performing a hot tapping operation on a pipe containing a first fiuid under pressure, whereby a coupon is cut from the wall of said pipe, comprising the steps of:

forming an elongate chamber with one end thereof Vin communication with that portion of said wall of said pipe from which said coupon is to be cut,

placinfy a fluid pressure actuated drilling means having a drill -bit within said chamber,

applying a second iiuid under pressure to said chamber to thereby operate said drilling means by rotating said bit,

advancing said 'bit into said wall during rotation of said bit,

continuing the application of said second uid to said drilling means until said bit initially penetrates Said wall, to thereby permit the escape of said first fluid from said pipe to said chamber,

applying said first liuid to said drilling means to continue the rotation of said bit until a coupon is cut from said wall,

withdrawing said drilling means to a portion of said chamber which is spaced apart from said wall, and

sealing -oif a portion of said chamber from which said drilzing means was withdrawn.

4. The method of remotely performing a hot tapping operation wherein a coupon is cut from a pipe containing a irst gas under pressure, comprising the steps of:

securing an elongated tap riser to said pipe in a sealing relationship therewith and surrounding said coupon to be cut,

lowering a gas pressure actuated drilling means with a drill bit at the lower end thereof into said riser,

controllably closing the top end of said riser to form a chamber having communication with said wall from which said coupon is to be cut,

applying a second gas under pressure to said chamber to thereby operate said drilling means by rotating said bit,

advancing said bit into said wall during rotation of said bit,

continuing the application of said second gas to said drilling means until said bit initially penetrates said wall, to thereby permit the escape of said first gas from said pipe to said chamber,

applying said first gas to said drilling means to continue the rotation of said `bit until a coupon is cut from said wall,

withdrawing said drilling means from said riser while maintaining the gas pressure therein, and

sealing off a portion of said riser from which said drilling means was withdrawn.

5. An apparatus for performing a hot tap operation on a container having a fluid under pressure contained therein, comprising:

an elongate uid tight housing having an open end adapted for securing to said container and enclosing the section of the wall of said container which is to be tapped,

a cutting means disposed within said housing with the cutting surface thereof adapted to engage said wall,

driving means connected to said cutting means for rotating said cutting means during operation of the apparatus,

releasable anchor means connected to said driving means and releasably engaging the inside wall of said housing in a fixed relationship during operation of the apparatus, and

means for radvancing said cutting means toward said wall while said anchor means is engaged.

6. An apparatus for performing a hot tap operation on a container having a first iiuid under pressure contained therein, comprising:

an elongate fluid tight housing having an open end adapted for securing to the wall to said container and enclosing that portion of said wall which is to be tapped,

an annular cutter disposed within said housing with the cutting surface thereof adapted to engage said wall which is to be tapped,

a fluid pressure motor connected to said cutter for rotating said cutter during operation ot the apparatus,

means for supplying a second fluid under pressure to said housing for operating said motor,

releasable anchor means connected to said motor and adapted to releasably engage the inside wall o said housing in a fixed relationship during operation of the apparatus, and

means for advancing said cutter toward said wall when said anchor means is engaged.

'7. The apparatus as claimed in claim 6 wherein:

said anchor means are radially expandable and adapted to frictionally engage the inside wall of said housing, and wherein said housing is provided with exhaust means for controllably releasing said second iuid from said motor.

8. An apparatus for cutting a coupon from a container having iiud under pressure contained therein, comprising:

a tiuid tight housing defining an elongate chamber and having one end adapted to be connected to said container and to surround the coupon to be cut,

an annular cutter disposed within said housing with the cutting edge thereof adapted to engage said coupon,

a guide bit centrally positioned within and secured to said annular cutter and having the leading end thereof extending beyond said cutting edge of said annular cutter,

a iiuid motor adapted to be operated by pressurized fluid contained in said chamber and connected to said cutter for rotating said cutter and said guide bit,

means for supplying a motive -iiuid under pressure to said chamber,

an exhaust means provided in said housing for controllably releasing said motive iuid from said motor and thence from said chamber,

means for feeding said cutter and said guide bit longitudinally in said chamber and against said coupon to be cut.

9. The apparatus as claimed in claim 8 wherein said exhaust means includes:

an exhaust valve provided in said housing, and

an exhaust tube connecting said valve and the exhaust port of said motor and forming -an exhaust channel therebetween.

1). rihe apparatus as claimed in claim 8 wherein said means for feeding said cutter and said guide bit longitudinally in said chamber includes:

expandable Vanchor means connected to said motor for frictionally engaging the inside wall of said housing when in the expanded condition, and fluid pressure actuated means for advancing said cutter and said bit toward said coupon. il. The apparatus as claimed in claim 8 wherein: the upper end of said housing deiines an enlarged chamber communicating with said elongate chamber, and having a reel provided in said enlarged chamber and journaled for rotation in said upper end, and an elongate flexible support member connected to said cutter and adapted to roll on and off of said reel and to support said cutter during raising and lowering thereof. 12. A hot tapping apparatus for lowering into a side branch connected to a pipe containing a first fluid under pressure and for cutting a coupon from said pipe at a point inside of the lower end of said side branch, said ap- TO paratus comprising:

'15 said cutting means for frictionally engaging the inside walls of said side branch,

piston means connected to said anchor means for advancing said cutting means,

a pressurized housing adapted for communicating with and securing to the upper end of said riser in a uid tight seal, t

means for moving said drilling means into and out of said side branch and including a hose reel journaled for rotation in said housing,

a ilexible hose supported on said reel, connected to said drilling means and communicating with the exhaust port of said motor,

Vmeans for supplying a motive fluid to said housing for operating said motor,

means for exhausting said motive fluid from said hose and said housing, and

conduit mems supported by said reel for supplying another presurized uid to operate said anchor means and said piston means.

13. The apparatus as claimed in claim 12 in which:

said motor is driven by said motive fluid contained in said housing, and

said anchor means includes at least two shoes which are radially expandable by a second piston means.V

14. ri`he apparatus as claimed in claim 12 wherein:

said means for raising and lowering said drilling means includes a support cable connected to said drilling means and supported on said reel.

l5. The apparatus as claimed in claim 12 including:

a safety valve connected to said hose and communicating between the chamber inside said hose and the chamber inside said housing and for maintaining a pressure differential therebetween below a predetermined level.

16. A hot tapping apparatus for insertion into a side branch connectedrto a pipe containing a first gas under pressure and `for cutting a coupon from said pipe at a point inside of said branch said apparatus comprising:

a uid tight housing adapted for communicating with and securing to the open end of said branch in a sealing relationship,

valve means for supplying pressurized motive iluid to said housing,

drilling means adapted for movement through lsaid branch and including a fluid motor adapted to be driven by said motive fluid contained in said housing,

at least one shoe connected to said motor and which is radially expandable for functionally engaging the inside wall of said branch and anchoring said drilling means,

annular cutting means rotatably driven by said moto-r, and

means for advancing said cutting means relative t to said anchor means, means for moving saidvdrilling means through said branch including Y a reel journaled for rotation in said housing, a exible hose supported on said reel, connected to said drilling means, and communicating withV the exhaust part of said motor, and a sup-port cable carried inside said hose for supporting said drilling means, valve ymeans for exhausting said motive fluid from said hose and said housing and for maintaining the .pres-Y a fluid tight housing adapted for communicating with and securing-to the upper end of said riser in a seaiing relationship, i

valve lmeans for supplying a second pressurized gas to said housing, i

drilling means adapted for lowering in said riser and including:

Va control block having a first and second piston means provided therein, Y

at least one anchor member connected to said block and kradially expandable by said tirst piston means,

an inner tubular shell connected at one end to said secondpiston Vmeans and at the other end to a motor housing,

said motor housing extending downwardly from said inner shell,

on outer tubular shell, the lower end of which is secured to the lower portion of said motor housing in iixed relationship thereto,

a middle tubular shell connected to said block and positioned between said inner shell and said outer shell for telescopic movement therewith aspecitied distance, Y

stop means for limiting said telescopic movement and the relative circumferential (movement between said inner and outer shells and said middle shell, Y a huid pressure motor mounted in said motor housing, and an annular cutter driven by said motor and adapted to engage said pipe from which said coupon is to be cut, 'Y means for raising and lowering said drilling means vin said riser, i means for supplying another pressurized uid to said Jirst and second piston means, whereby said anchor -maybeexpanded thereby and said inner and outer Vshells may be moved telescopicaliy relative to said middle shell a predetermined distance.

1,8. Theu apparatus as claimed in claim 17 wherein:

said means for raising and lowering said drillingmeans includes: t

a hose reel mounted in said housing, a lexiblevhose supported AYon said.v reel and com- Y municating between the. exhaust part ofv said motor and the atmosphere, and a support cable carried inside said hose for supporting said drilling means vduring raising and lowering thereof, and having conduit means carried inside said hose for supplying another pressurized fluid to operate said irst and secondV piston means. 19. The method of performing a hot tapping operation on a container having a fluid under. pressure contained therein, comprising the steps of:

forming an enclosed chamber adjacent to and in communication with a portion of the external wall of said container,

placing a fluid pressure actuated drilling means within said chamber in drilling engagement with said portion of said wall,

cutting a iluid pressure releasing hole through said portion of said wall, to thereby permit the escape of said fluid from said container into said chamber,

applying said escaping fluid to operate said drilling means,

continuing the operation of saiddrilling means until a hole of predetermined size is formed in said portion of said` wall.

2t). An apparatus for cutting an opening in a container, said apparatus comprising:

an elongate tluidrtight housing having an open end adapted for securing to lsaid container and enclosing 17 18 the section of the wall of said container which is to References Cited gent tu t d d .11. e s d. po d mh UNITED STATES PATENTS a u1 pressure aca e n mg rn an 1s se 1 in said housing in drilling engagement with said sec- 21651222 9/1953 Mueller et al' 77-37 3,169,415 2/1965 Weitz 77-37 X tion of said wall, 5 ymeans for supplying a uid to said housing in suicient 3225828 12/1965 Wlsenbaker et al 165 55 quantities to pressurize said housing and to actuate y Said drilling means JOHN F. CAMPBELL, Przmaly Examllner. means for advancing said drilling rmeans toward said J. D. HOBART, Assistant Examiner.

section of said wall while said drilling means is actuated.

Claims

1. THE METHOD OF PERFORMING A HOT TAPPING OPERATION ON A CONTAINER HAVING A FIRST FLUID UNDER PRESSURE CONTAINED THEREIN, COMPRISING THE STEPS OF: FORMING AN ENCLOSED CHAMBER ADJACENT TO AND IN COMMUNICATION WITH A PORTION OF THE EXTERNAL WALL OF SAID CONTAINER, POSITIONING A FLUID PRESSURE ACTUATED DRILLING MEANS WITH A DRILL BIT WITHIN SAID CHAMBER AND HOLDING SAID BIT IN DRILLING ENGAGEMENT WITH SAID WALL, APPLYING A SECOND FLUID UNDER PRESSURE TO SAID CHAMBER TO THEREBY OPERATE SAID DRILLING MEANS, ADVANCING SAID BIT INTO SAID WALL DURING OPERATION OF SAID DRILLING MEANS, CONTINUING THE APPLICATION OF SAID SECOND FLUID UNTIL SAID BIT INITIALLY PENETRATES SAID WALL, TO THEREBY PERMIT THE ESCAPE OF SAID FIRST FLUID FROM SAID CONTAINER INTO SAID CHAMBER, APPLYING SAID FIRST FLUID TO OPERATE SAID DRILLING MEANS TO COMPLETE THE CUTTING OF AN OPENING INTO SAID CONTAINER.