The present invention relates to monitoring of tool wear and more particularly, but not by way of limitation to monitoring of drill-bit or boring machine cutter wear and environmental status via a redundant sensor wear transducer with a remote recessed reflector antenna.
An antenna is an electrical device that converts electrical power into radio waves and vice versa. Typically, antennas are used with a radio transmitter or a radio receiver. In transmission, a radio transmitter supplies an electric current oscillating at radio frequency (i.e. a high frequency alternating current (AC)) to the antenna's terminals. The antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of an electromagnetic wave in order to produce a voltage at its terminals, that is applied to a receiver to be amplified.
Antennas are essential components of all equipment that use radio and are used in systems such as, for example, radio broadcasting, broadcast television, two-way radio, communications receivers, radar, cellular phones, satellite communications, and the like. In addition, antennas are also used in devices such as, for example, wireless microphones, garage openers, RFID tags, Bluetooth enabled devices, and the like.
Typically, an antenna consists of an arrangement of metallic conductors electrically connected to a receiver or a transmitter. Such antennas are typically exposed from and/or extend outwardly of supporting structures. Such exposed antenna mountings/configurations do not lend themselves for use on “wear surfaces” and downhole drilling equipment where the antenna area could be impacted and/or abraded by external forces.
Addressing conventional antennas, an oscillating current of electrons forced through the antenna by a transmitter creates an oscillating magnetic field around the antenna elements, while the charge of the electrons also creates an oscillating electric field along the antenna elements. These time-varying fields radiate away from the antenna into space as a moving transverse electromagnetic field wave. Conversely, during reception, the oscillating electric and magnetic fields of an incoming radio wave exert force on the electrons in the antenna elements, causing them to move back and forth, creating oscillating currents in the antenna. For the antennas to effectively transmit signals, it is preferred to place the antennas on non-recessed surfaces.
The present invention relates to monitoring of tool wear and more particularly, but not by way of limitation to monitoring of drill-bit or boring machine cutter wear and environmental status via a redundant sensor wear transducer with a remote recessed reflector antenna. An example of one embodiment is an intelligent blast-hole drill bit that includes a housing embedded into a cavity in a bit body. A controller is disposed in the housing. An external antenna is disposed in the housing and coupled to the controller. An internal antenna is disposed in the housing and coupled to the controller. A wear transducer is disposed in the housing and coupled to the controller.
For a more complete understanding of the present invention and for further objects and advantages thereof, reference may now be had to the following description taken in conjunction with the accompanying drawings in which:
Various embodiments of the present invention will now be described more fully with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
Blast holes are used to load explosives to break up rock formations in mines to strip waste rock and gain access to ore bodies, and to break up ore bodies for mining purposes. A simplified blast hole drilling process is shown in
An Intelligent Blast-Hole Drill Bit with Redundant Transducer Wear Sensor and Remote Recessed Reflector Antenna enables an up-hole computer to receive wear status, bit temperature, precision real time bit shock and vibration, strain, pressure, and other sensor parameters to also derive bit-whirl, reliably and wirelessly from the drill bit up the blast hole. Redundant recessed reflector antennas installed in the bit transmit the data inside and outside the drill pipe so that if one path becomes blocked, the other may still be able to communicate.
A bit body, shown in
Installation of the Invention into the Drill Bit:
Intelligent Wear Monitoring
Bit body wear may also be monitored.
Direct Wear Monitoring Using Redundant Resistors as Transducers:
Still referring to
Redundant transducers and traces improve the monitoring reliability of the sensors. Single component, connection, or trace failures resulting from defects in manufacturing, extremes in temperature, shock, or vibration of the operating environment are detected and compensated for in the processing circuitry. As an example, if the parallel combination of R1a and R1b equals the value of R1, the analog voltage detected at the processor input is V/2. If a failure of R1a, R1b or a connection or trace path to either of these resistors results, due to a manufacturing fault, temperature extremes or from shock or vibration, one of the resistors will be omitted from the circuit. This will result in the resistance of R1 being half the resistance of the remaining connected resistor (R1a or R1b). The voltage detected at the input will then be V/3. This voltage level will indicate to the processor that the failure may not be related to wear. If the voltage level is due to wear, it will not make a difference. The other resistor will soon be removed by wear. Until both resistors in the pair are faulted, the wear-point will not be considered to have been reached. In sensors that do not have redundancy, failures in any of the traces or transducer will incorrectly indicate that the wear point was reached.
Expanding into the sensor diagram shows the spacing of the individual resistor pairs 32 which are broken away when the wear reaches them. In this example, the resistors are spaced at intervals that will indicate wear in increments of approximately 10%.
The previous drawing was further expanded to show the details of one redundant resistor pair. One resistor 33 is located on the top surface of circuit board 34, the other resistor 35 is located on the bottom side. Traces that carry sensor signals are on the top 36, middle 37 and bottom 38 layers of the circuit card.
Putting traces 36, 37, and 38 on multiple circuit board layers reduces the width of the circuit board to fit in a smaller hole in the drill bit. By way of example, this example uses a pair if resistors 33 for redundancy. The use of more transducer parts to increase the redundancy is considered a part of this invention.
Indirect Wear Monitoring Using Accelerometers:
As the bit wears, the characteristics of its rotation in the hole will change. Accelerations associated with bit rotation can be monitored by accelerometers on the bit or bit collar and the amount of wear can be estimated. Monitoring wear in this way does not require installation of an embedded wear ladder. A high degree of whirl, for example, is indicative of significant bit wear. If acceleration readings suggest that the bit is violently whirling in the hole, notification can be sent to the operator to check the bit for wear.
Indirect Load Monitoring Using Strain Gauges:
Parameters like torque on bit and weight on bit are typically estimated using sensors and gauges on the drill rig. These estimations can be inaccurate because there may be something happening between the drill rig and the drill bit such that all the forces from the rig are not transferred to the bit. Strain gauges located on sides walls of the cavity 17 of the bit may be used to better infer the torque and weight on bit. The strain at any given location on the bit is related to the stresses on the bit. To associate strain read by the gauges and stress on the bit, the system must be calibrated. Known stress is applied to the bit and the strain read. When unknown stresses associated with torque and weight on bit are applied, strain can be used to calculate those stresses.
Pressure Monitoring Using Plunger, Lever Arm, and Strain Gauges:
Pressure may be monitored using a system that includes a plunger, lever arm, and strain gauge.
Transmission of Monitored Data to the Machine Operator:
From the perspective of monitoring the wear of a bit body, since there are no practical means of attaching wires for communication, the application is considered to be remote. The monitoring electronics are embedded in the bit and the bit is used to cut rock, ore, and other harsh abrasive materials. Powering the electronics and sending the signals to the operator is a challenge. For the bit, the monitoring electronics are to be powered by battery. The batteries and controller are installed as a module using screws. If the battery or controller fail during operation, it is possible to replace them to extend the life of the bit. When the bit is worn out, it is possible to move the controller and battery to another bit, however, the wear sensor will need to be replaced, since it wears away with the bit.
Transmission of data is accomplished by use of recessed antennas mounted in the surfaces of the drill bit which are least exposed to abrasion. The antenna may be encapsulated or otherwise covered with materials that will best withstand the abrasion. PTFE (Polytetrafluoroethylene, also known as Teflon) is an example of one material that may be well suited to this application for the following reasons: it has low surface friction; it is rigid; and it does not significantly attenuate radio frequency transmissions. Small gaps around covers made of materials such as PTFE, may be sealed from moisture using epoxy or other suitable sealants. The size of the aperture used for wireless transmission must be minimized to best protect the antenna and associated circuits. One or more antennas may be implemented for this application, based on the need to radiate and receive signals in multiple directions. An example embodiment of remote dual antennas with recessed reflectors is shown in
Referring now to
The antenna 39 and circuit board 42 is further protected with a cover 48 formed out of a material (such as PTFE) that fills the cavity 43 in front of the antenna 39 and which is attached by means of two screws 49. Connectors 41 are attached to RF cables 50. RF cables 50 carry signals to and from the transceiver and processing circuit board 51. Dimensions of the cavity allow the radiation pattern 52 to be ninety degrees (or greater, by means of altering these dimensions, when practical). The set of cavity 43 dimensions in this example may obviously be altered, as required, for similar embodiments of this invention. Recessing the antenna 39 changes the radiation characteristics from an omnidirectional configuration that is characteristic of radiation reflected off a flat reflector to radiation reflected off of a horn antenna. This will make the antenna 39 beam operate in a directional pattern.
Because the antennas are mounted in a drill bit, the signal radiation will deflect off of other objects, such as adjacent, drill parts, walls of the blast hole and drill pipes or the drill rig at the top of the hole to disperse to the antennas on the other end of the transmission. In some cases, if a drill is mounted in an area where wires may be used for data transmission, wired technology may also be used.
Boring machines are used to excavate vertical or horizontal shafts in the mining and tunneling industries. With raise boring, a pilot hole is drilled from the surface to intercept the subsurface workings. After the pilot hole has penetrated into the workings, a boring head having several rolling cutters (often called a cutting head) is fixed to the end of the drill string. The raise boring machine then pulls the cutting head towards the surface as it rotates, cutting and breaking rock that falls down to the workings where it can be hauled out. As opposed to blind boring, raise boring requires subsurface workings to be connected to the shaft to be excavated before the shaft can be constructed. The invention described herein relates to both raise boring and blind boring machines.
In an exemplary embodiment shown in
Each cutter assembly monitoring system has the ability to communicate with other cutter assemblies in a wireless mesh network, as shown in
In one embodiment, the central receiver antenna 1006 may be a transceiver or connected to a transmitter antenna that sends the signal up the annulus of the drill pipe 1002 and pilot hole wall, using repeater transceivers embedded in the outside of the drill pipe 1002. The nature of this embedment of antennas is discussed in the section “Description of the Recessed Reflector Antenna.”
In another embodiment, the central receiver antenna 1006 is embedded in a dielectric window that allows RF to reach the inside of drill pipe 1002 while the drill pipe 1002 remains sealed. The receiver antenna 1006 may be a transceiver or connected to a transmitter antenna that sends the signal up the center of the drill pipe using repeater transceivers embedded in the inner wall of the drill pipe 1002. The nature of this embedment of antennas is discussed in the section “Description of the Recessed Reflector Antenna.”
In another embodiment shown in
Although various embodiments of the method and system of the present invention have been illustrated in the accompanying Drawings and described in the foregoing Specification, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit and scope of the invention as set forth herein. It is intended that the Specification and examples be considered as illustrative only.
This application is a continuation of U.S. patent application Ser. No. 15/660,611. U.S. patent application Ser. No. 15/660,611 claims priority to each of U.S. Provisional Patent Application No. 62/368,807; U.S. Provisional Patent Application No. 62/437,120; and U.S. Provisional Patent Application No. 62/466,188. U.S. patent application Ser. No. 15/660,611; U.S. Provisional Patent Application No. 62/368,807; U.S. Provisional Patent Application No. 62/437,120; and U.S. Provisional Patent Application No. 62/466,188 are each incorporated herein by reference.
Number | Name | Date | Kind |
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10605004 | Brunner | Mar 2020 | B1 |
Number | Date | Country | |
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62466188 | Mar 2017 | US | |
62437120 | Dec 2016 | US | |
62368807 | Jul 2016 | US |
Number | Date | Country | |
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Parent | 15660611 | Jul 2017 | US |
Child | 16804145 | US |