MXPA95001570A - Apparatus to drill pipe to high pres - Google Patents

Abstract

An apparatus for drilling an opening in an existing pipe under pressure includes an elongated drill body having means at one end for joining a pipe, a drill bar having a rotary advance screw therein, by which Drill bar is positioned axially, and a valve that responds to the pressure activated by the differential pressure between the inside of a pipe and the inside of the body of the drilling machine to control the hydraulic pressure inside the body of the drilling machine to counterbalance with it the hydraulic force applied to the drilled bar

Description

APPARATUS FOR DRILLING HIGH PRESSURE PIPING Cross-reference with related requests This request is not related to any co-pending patent applications.

BACKGROUND OF THE INVENTION Description of the Prior Art The use of machines for drilling openings in pipes is well known. The previously issued US Pat. Nos. 3,614,252 entitled "Apparatus for drilling"; 4,5709,484 entitled "Underground drilling machine"; and 4,880,028 entitled "Termination machine" are exemplary of such devices. The contents of those North American patents issued are here incorporated for reference. The prior patents illustrate and describe techniques for drilling in a pipeline while under pressure without interrupting the transportation of gases or liquids through the pipeline. Although the basic operation as disclosed below remains intact, this invention improves the operation in various ways, as disclosed below, which function to increase the operating range of the drilling apparatus and to provide speed controls for the drilling apparatus. enough energy.

SUMMARY OF THE INVENTION Cutting an opening in a pipe wall is difficult and time consuming and requires well-devised drilling equipment that must withstand the rigors of cutting through heavy galvanized steel while under pressure. It is known that the pressure of a pipe acts against the drilling apparatus thus reducing the cutting ratio while increasing the operational loads through the internal working mechanisms of the apparatus. Increased wear and tear in the drilling machine reduces its efficiency and life. The present invention is directed towards a means whereby the drilling apparatus can work more efficiently and effectively when cutting in a pipe with high existing pressures. Existing designs of drilling equipment are limited in their performance by the high pressures of the pipe. The pressure of the pipe acts on the protected area in the drilling bar of the drilling apparatus and generates a load through the advance screw and nut of the apparatus. The feed screw mechanism is the primary means of advancing a drill rod in a pipe. Increasing the load through the lead screw requires greater input twists to operate the equipment. Higher loads result in increased fatigue by all structural means that can eventually result in premature failure. An object of this invention is to provide a drilling apparatus that will reduce the operating loads through the lead screw, thus reducing the amount of torque required to operate the drilling apparatus at higher pipe pressures. This is carried out using hydraulic energy, gaseous energy or even the pressure of the gas that exists in the pipe or similar within the body of the drilling machine. The pressure supply acts on the protected area of the drill rod and generates a load through the feed screw and nut and the related thrust bearings. This load counterbalances the opposing pressure released from the pipeline, which reduces the total input torques required to operate the equipment. This in turn reduces the fatigue ordinarily imposed by all structural members, thus reducing the premature failure of the key components. An additional objective of this disclosure is to provide more efficient energy speed control. Commonly the speed of rotation of the drill rod is controlled by the speed of the arrow of the pump of the power unit. There are two main problems with this method: (1) the operator must adjust the rotary cutting speed via the power unit by adjusting the speed of the power unit; (2) At lower cutting speeds, the motor of the power unit may not perform at the optimum level necessary to generate enough torque to penetrate the pipe. The present invention utilizes a charge sensing and circuitry pump that sets and maintains the rotary cutting speed at a substantially constant speed that is independent of the speed of the motor. Load-sensing pumps of this type maintain a constant pressure differential between the pressure required to operate the load and the outlet pressure of the pump. This flow, in turn, is proportional to the opening of the pressure control valve regardless of the speed of the pump shaft. These and other objects, advantages and features of this invention will be apparent to those skilled in the art upon consideration of this specification, including the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS Figure IA and IB represent an external view of a drilling apparatus employing the principles of this invention, shown partially in cross section. Figure 2 is a schematic view of the hydraulic system of the drilling apparatus illustrating the flow of hydraulic fluid for various operations performed with the apparatus by a drilling operation.

DESCRIPTION OF THE PREFERRED MODALITIES Referring to the drawings and first the Figures IA and IB the apparatus for drilling under pressure of this invention is illustrated partially in section. The way of joining the drilling machines with the pipes is well known. The previously issued U.S. Patent No. 4,880,028 entitled "Finishing Machines, is exemplary of such a joint". The content of this previously issued US patent is incorporated for reference. For a detailed description of such a union, see Figures IA and IB and column 3, lines 10 to 31 of U.S. Patent 4,880,028. Referring first to Figures IA and IB, an apparatus for drilling under pressure is generally indicated by the number 10. The apparatus includes a lower tubular member 12, a tubular housing portion 14, a collar portion 16, a gearbox 18 and a cutting portion 1. Arranged concentrically within and coaxially with the housing member 14 and the tubular member 12, there is a transmission tube 20. Arranged concentrically within and coaxially with the transmission tube 20 is a drill rod 22. Placed concentrically inside and coaxially with the drill bit 22, there is a lead screw mechanism 24. When a pipe to be tapped has fluid pressure such that the fluid pressure causes a load on the components of the drilling apparatus. When the cutting portion 19 cuts a pipe (not shown) to be drilled, the pressure of the pipe is exerted upwardly against the lower ends of the drill bit 22 of the feed screw mechanism 24. This pipe pressure works against the descending force of the drill rod and the feed screw according to a cutter (not shown) that is attached to the cutting portion 19 cuts through the wall of the tube (not shown). When sufficient force is applied to rotate the drill bit 22 and the lead screw 24, the internal drive member threads 23 engage with the external threads in the lead screw to axially advance the drill rod 22. Fluid pressure in the pipe acts against the feed screw and therefore additional torque is required to rotate the feed screw. The typical drilling apparatus as previously known does not contain any fluid or oil. However with this invention a fluid is placed inside the drilling apparatus to reduce the load on the components of the apparatus such as on the drill rod and the advancing screw caused by the pressure of the pipe. The fluid pressure inside a pipe being drilled is used to provide a hydraulic signal that is used to apply hydraulic pressure to the components of the drilling machine to counteract the upward pressure of the pipe. A reduction in component loads achieved by balancing the pressure through the components, such as the drill rod and feed screw, allows the drilling machine to operate more efficiently and effectively. The lower tubular member 12 has a lower end 28 which is configured to be attached to a shutter (not shown) which, in turn, is attached to a pipe (not shown) to be drilled. The lower end 28 has a tubular opening 30 which receives the drilling rod 22 and a small diameter opening 34 communicating with a passage 32. The fluid pressure in the opening 34 coming from of a pipe being drilled communicates through the passage 32 to the opening 40 which receives a conduit 41 which is connected to a detector element 54 (see Figure 2). The sensing element 54 detects the amount of pressure of the tube present in the inlet 34 and when opening or closing the fluid flow paths in the detector element that regulates the flow of the fluid under pressure to the inlet opening 62 in the collar portion 16 (Figure IA). The regulated fluid from the detector device 54 enters the opening 62, it infiltrates the transmission bearings 64 and flows through the passage 66 which is in communication with a reservoir area 68. The fluid regulated in the reservoir area 68 applies a downward pressure against the lead screw mechanism 24 and the boring bar 22 and helps to balance the tension imposed on the bearings 64. The regulated fluid is also introduced into the longitudinal passage 70 from the reservoir area 68 located between an internal side wall 72 of the transmission tube 20 and an external side wall 74 of the drill rod 22. The fluid regulated in the passage 70 communicates with the passage 102 to allow regulated fluid pressure within the area 69. The fluid pressure within the area 69 helps to counteract the upward pressure of the fluid from the applied pipeline. against the drill bar 22. This feature further reduces the loading of the feed screw and consequently reduces the torsion required to operate Set the feed screw to advance the drill bar. The pressure of the annular area 84 is released through the opening 80 and the second conduit 79 returns to a hydraulic fluid sump as shown in Figure 2.

OPERATION OF THE DRILLING DEVICE Referring to Figure 2, the pump 108 supplies hydraulic fluid used to maintain the pressure within the interior of the housing 14 of the drilling apparatus, the pressure being applied to the opening 62. Through the conduit 41 pressure is applied to the detector device 54. The position of the detector device 54 is controlled by the pressure within a pipe that is to be tapped as soon as the cutter (not shown) penetrates the pipe. The pipe pressure is applied from the opening 40 via the conduit 41 to control the position of the detector device 54. The detector device 54 has three positions controlled by the pressure differential through the device. When the pressure in the opening 40 and 62 is the same, the sensing device 54 is in the middle position and no pressure is applied from the pump 108 to the drilling apparatus. When the pressure in the opening 40 exceeds that within the drilling apparatus as revealed in the opening 62, the sensing device 54 is moved so that the pressure of the pump 108 is applied to the opening 62. When this pressure equals that of the In the interior of the pipe, as revealed in the opening 40, the detector device 54 will be moved to the middle or closed position. When the pressure inside the drilling apparatus exceeds that of the opening 40 (the pressure of the pipe after a pipe has been penetrated) the sensing device 54 returns to the illustrated position as shown, in which the opening 62 is attached to a hydraulic sump 36 to drain the fluid from inside the drilling apparatus in this manner. When the pressure in the openings 40 and 62 is again balanced, the detector device returns to the middle position. Thus, the sensing device 54 automatically regulates the pressure within the interior of the drilling apparatus to balance the hydraulic forces applied against the drill rod. This means that the lead screw does not have to counteract the force caused by the pressure of the pipe during a drilling operation. The test valve 120 can be manually depressurized before the drilling apparatus is put into service to apply hydraulic pressure from the pump 108 to the interior of the machining apparatus via the conduits 60 and 79 to test the leak-proof seals. Otherwise, valve 120 is not involved in the automatic pressure balancing feature of the drilling apparatus. The pump 122 supplies hydraulic pressure to activate the hydraulic motor 104 which rotates the drill rod 22 and the hydraulic motor 106 which rotates the drive train mechanism 109, 110, 100 (see FIG. IA) which rotates the feed 24. The rotation of the drill rod is controlled by the valve 44 manually positioned by the lever 46. One side of the hydraulic motor 104 is always connected to the fluid sump 36. In the valve position 44 illustrated, both sides of the motor 104 they are attached to the sump 36 so that the motor 104 is not driven. However, when the lever 46 is pushed to move the valve 44 to the far right position the hydraulic force coming from the hydraulic pump 122 is applied to the motor 104 to rotate the arrow 104A to rotate a worm gear 104B the which in turn rotates the gear 98 (see FIG. IA) and thereby the drilling bar 22. The speed of rotation of the drill rod is controlled by the operator controlling the position of the valve 44. The valve 48 controls the direction of rotation of the motor 106 and thereby the direction and speed of rotation of the feed screw 24. The position of the valve 48 is controlled manually by the position of the lever 50. The speed of rotation of the feed screw controls the advance or removal of the drill rod. That is, when the feed screw 24 rotates faster than the auger 22, the drill bar is advanced. When the lead screw 24 rotates slower than the drill rod 22, the drill rod 22 is removed. More specifically, a chain drive for sprocket is used to rotate the feed screw 24 positioned within the drill rod 22. The threads on the feed screw engage the drill rod and both rotate due to the hydraulic drive motor and the chain assemblies for cogwheels. The chain drive for the sprocket is designed so that the feed screw rotates slightly faster than the drill rod. The speed differential between the two causes the feed screw to advance or remove the auger. Valves 44 and 48 are not fast acting but are continuously variable in the operation of their internal passages. As the operator places these valves (independently and not at the same time) the fluid pressure from the pump 122 is communicated to the hydraulic motors 104 and 106, respectively. The fluid pressure supplied to those motors is communicated back to the flow control mechanism of the pump 122 through the conduit 109. The flow control mechanism of the pump 122, commonly known in the power fluids industry as of load sensing type, adjusts the pump output flow to maintain a constant pressure difference between its outlet pressure and the pressure in conduit 169. As valve 44 or 48 is further opened, pump 122 supplies more fluid to maintain the constant pressure difference. From here, the variable speed control of the motors 104 and 106 is obtained independently of the speed of the arrow 122 of the pump (engine speed) and only the pressure required to rotate the hydraulic motors 104 and 106 is supplied. As has been described, the drilling tool is a device that enables one to perform a machine operation to drill a hole in an existing pipe. A drive train of gears, sprockets, and lead screw, provide the mechanical actions referred to to rotate and advance the bit of cutting bit. Once the hole has been completed, a clutch in the drive train is decoupled and the auger can be extended or retracted by the operation of the supply motor 105 and 106 which rotates the feed screw 24 only and rapidly extends or retract the drill rod 22. The operation of the drilling tool is limited by the pressure in the pipe in which the male is penetrating. The pressure acts on the protected area of the drill rod and generates a load on the feed screw and the thrust bearings. Sufficient torque must be applied to the lead screw by the motor to overcome the load to extend or retract the drill rod. The limiting factor starts from the availability of the torsion coming from the supply motor to operate the tool, by applying hydraulic pressure inside the drill bar, the opposing force coming from the pipe is counteracted. This reduces the loading of the feed screw and consequently reduces the torque required to operate the machining device at maximum pipe pressures. The combination of an advancing screw and hydraulically assisted drill rod creates a drilling tool that uses hydraulics to provide the operating thrust and feed screw to mechanically control the feed rate of the drill rod and cutter. The hydraulic pressure is restricted within the body of the tool by several hydraulic seals. The strategic placement and dimensioning of the seals can reduce the loads on several of the bearings. The reduction of the loads allows the tool to work in higher pressure pipes using the same or fewer components than the previous designs. The pressure inside the machining tool is supplied by a pressure source 108. As previously described, this pressure is controlled using the control valve 54 which adjusts the pressure of the drilling tool based on the pressure of the pipe detected in the opening 34 at the lower end of the housing of the drilling device. By using a special load detecting pump 122 and hydraulic circuitry, it is possible to set and maintain the rotary cutting speed at a constant prefix level independent of the speed at which the pump is driven. Such load sensing pumps of this type maintain a constant pressure differential between the pressure required to operate the load and the outlet pressure of the pump. The flow becomes proportional to control the valve opening regardless of the speed of the pump drive shaft. In this way, it can be seen from the above description that the apparatus of this disclosure is designed to provide a force contrary to the pressure inside a pipe that is to be tapped. An opposing force is generated by applying fluid pressure in a protected area within the drilling apparatus, which opposes the projected area of the drill rod subjected to the pressure of the pipe. A load opposite to the direction of the load generated by a pressure of the pipe on the drill bar is then generated. The claims and the specification describe the presented invention and the terms that are employed in the claims trace their meaning from the use of such terms in the specification. The same terms used in the prior art may be broader in meaning than those specifically employed herein. As long as there is doubt between the broader definition of such terms used in the prior art and the more specific use of such terms here, the broader meaning should be applied.

While the invention has been described with a certain degree of particularity, it is stated that many changes can be made in the details of construction and arrangement of the components without departing from the spirit and scope of this disclosure. It is to be understood that the invention is not limited to the embodiments disclosed herein for purposes of exemplification, but is limited only by the scope of the attached clause or clauses, including the full range of equivalences to which each element is enunciated. What is claimed is:

Claims (4)

1. NOVELTY OF THE INVENTION Having described the invention as above, it is considered as novelty and property is claimed as contained in the following: CLAIMS 1. - An apparatus for drilling an opening in an existing pipe or the like under high internal pressure, comprising: an elongated machine body for drilling having means for joining a pipe to be drilled; a feed screw positioned longitudinally inside the body of the boring machine that rotates about its longitudinal axis; A drill rod connected to the feed screw for axial movement relative to the drill rod under the relative rotation of the feed screw and the drill rod, the drill rod have means for holding a cutter for rotation by the drill rod and for movement by the drill rod in and out of coupling with a pipe; means for rotating the advancing bolt; an element for rotating the drill rod for drilling a pipe when it moves in coupling therebetween by the relative rotation of the feed screw and the drill rod; means for detecting the pressure of the pipe; means for controlling the hydraulic fluid pressure within the body of the drilling machine based on the pressure of the pipe to at least partially balance the forces applied to the drill rod; and means for controlling the rotation speed of the feed screw and the drill rod.
2. 2. The apparatus according to claim 1, wherein the drill rod is tubular and has a longitudinally extending central opening into which the advancing screw extends.
3. 3. - An apparatus for drilling an opening within an existing pipe or the like, comprising: an elongated drill machine body having a drill bar having means for receiving a cutter, the drill bar is movable axially to move a cutter in and out of coupling with a pipe; means for axially moving the drill rod; means to detect the hydraulic pressure of the pipeline; and means responsive to the hydraulic pressure to control the hydraulic pressure inside the drilling machine to at least balance in part the forces applied to the drill rod during a cutting operation.
4. 4. - The apparatus according to claim 3, wherein the element that responds to the hydraulic pressure of the pipe is a pressure activated valve that responds to the differential pressure between a pipe and the interior of said machine body for drilling. EXTRACT OF DISCLOSURE An apparatus for drilling an opening in an existing pipe under internal pressure includes an elongated drill body having means at one end for joining to a pipe, a drill rod having a rotary advance screw inside. of this, by means of which the drill rod is positioned axially, and a valve that responds to the pressure activated by the differential pressure between the inside of a pipe and the inside of the body of the drilling machine to control the hydraulic pressure inside the body of the drilling machine to counterbalance the hydraulic force applied to the drill rod.