US-20260126560-A1 - HORIZONTAL DIRECTIONAL DRILLING SONDE WITH ADVANCED MAGNETIC CORE TECHNOLOGY AND ASSOCIATED METHODS

Abstract

A transmitter is disclosed that includes an electromagnetically permeable ductile core formed from a flexible core material. An antenna coil is wound around the flexible electromagnetically permeable ductile core to surround at least one portion of the electronics region and another portion of the battery region. An elongated outer tube serves as an outer structural member of the transmitter that is sealable at first and second opposing ends. The core can be formed from a wrapped electromagnetically permeable sheet material such as silicon steel. An associated wrapping table and method are described.

Inventors

• Rudolf Zeller
• Scott Phillips
• Timothy Lang
• Jason Pothier
• Joseph Tyler Zrebiec

Assignees

• MERLIN TECHNOLOGY, INC.

Dates

Publication Date

20260507

Application Date

20241106

Claims (20)

1. 1 . A transmitter, comprising: an elongated inner tube defining at least a portion of an electronics region for receiving an electronics module and a battery region for receiving at least one battery; an electromagnetically permeable ductile core surrounding the elongated inner tube formed from a flexible core material; an antenna coil wound around the flexible electromagnetically permeable ductile core to surround at least one portion of the electronics region and another portion of the battery region; and an elongated outer tube serving as an outer structural member of the transmitter that is sealable at first and second opposing ends.
2. 2 . The transmitter of claim 1 wherein the elongated inner tube, the electromagnetically permeable ductile core and the antenna coil are encapsulated for receiving the elongated outer tube.
3. 3 . The transmitter of claim 1 wherein the antenna coil and the electromagnetically permeable ductile core are encapsulated between the elongated outer tube and the elongated inner tube such that the outer tube is bonded to the antenna coil and the electromagnetically permeable ductile core as part of an integral unit.
4. 4 . The transmitter of claim 1 wherein the electromagnetically permeable ductile core is formed from a flexible electromagnetically permeable sheet material.
5. 5 . The transmitter of claim 4 wherein the flexible electromagnetically permeable sheet material includes a thickness in a range from 0.001 inch to 0.005 inch.
6. 6 . The transmitter of claim 4 wherein the flexible electromagnetically permeable sheet material is wrapped around the elongated inner tube.
7. 7 . The transmitter of claim 6 wherein the flexible electromagnetically permeable flexible sheet material is wrapped to form a plurality of overlapping layers.
8. 8 . The transmitter of claim 4 wherein the flexible electromagnetically permeable sheet material is spiral wound around the elongated inner tube.
9. 9 . The transmitter of claim 4 wherein the electromagnetically permeable ductile core is formed from one or more individual sheets of the electromagnetically permeable sheet material.
10. 10 . The transmitter of claim 9 wherein the one or more individual sheets are wrapped sequentially around the elongated inner tube.
11. 11 . The transmitter of claim 9 wherein at least one individual sheet of the flexible electromagnetically permeable sheet material includes a length to form more than one complete wrap around the elongated inner tube and any underlying wraps of the electromagnetically permeable sheet material.
12. 12 . The transmitter of claim 11 wherein the electromagnetically permeable ductile core is formed from a metal alloy including silicon and iron.
13. 13 . The transmitter of claim 9 wherein each individual sheet of the flexible electromagnetically permeable sheet material includes opposing widthwise edges and at least one of the individual sheets is spiral wrapped to form an electrically isolating gap with a confronting widthwise edge of a successive one of the individual sheets in the spiral wrap.
14. 14 . The transmitter of claim 9 wherein at least one individual sheet of the flexible electromagnetically permeable sheet material includes opposing widthwise edges that are placed in a confronting relationship by the complete wrap around the elongated inner tube and any underlying layers.
15. 15 . The transmitter of claim 4 wherein the flexible electromagnetically permeable sheet material defines at least one elongated slot through a thickness thereof.
16. 16 . The transmitter of claim 4 wherein at least a portion of the flexible electromagnetically permeable sheet material defines a plurality of elongated slots through a thickness thereof.
17. 17 . The transmitter of claim 16 wherein an elongated dimension of the slots is aligned with an elongation axis of the elongated inner tube.
18. 18 . The transmitter of claim 16 wherein the flexible electromagnetically permeable sheet material includes a grain orientation and an elongated dimension of the slots is aligned with the grain orientation.
19. 19 . The transmitter of claim 4 wherein the electromagnetically permeable ductile core is formed from a single continuous sheet of the electromagnetically permeable sheet material.
20. 20 . The transmitter of claim 4 wherein at least one major surface of the electromagnetically permeable sheet material supports an electrical insulating layer.

Description

BACKGROUND The present application is generally directed to the field of horizontal directional drilling and, more particularly, to an inground device or sonde and associated methods. While not intended as being limiting, one example of an application which involves the use of an inground device or sonde (i.e., transmitter) is Horizontal Directional Drilling (HDD). The latter can be used for purposes of installing a utility without the need to dig a trench. A typical utility installation involves the use of a drill rig having a drill string that supports a boring tool, serving as one embodiment of an inground tool, at a distal or inground end of the drill string. The drill rig forces the boring tool through the ground by applying a thrust force to the drill string. The boring tool is steered during the extension of the drill string to form a pilot bore. Upon completion of the pilot bore, the distal end of the drill string is attached to a pullback apparatus which is, in turn, attached to a leading end of the utility. The pullback apparatus and utility are then pulled through the pilot bore via retraction of the drill string to complete the installation. In some cases, the pullback apparatus can comprise a back reaming tool, serving as another embodiment of an inground tool, which expands the diameter of the pilot bore ahead of the utility so that the installed utility can be of a greater diameter than the original diameter of the pilot bore. Locating systems are commonly used in HDD to help ensure that the underground utility is installed along the desired path (including depth) underground. Walkover locating systems are the most common form of locating system, and typically include a battery-powered transmitter (or sonde) that is carried by a drill housing. The drill housing defines a cavity for receiving the transmitter proximate to the boring tool, and is configured to withstand the rigors of drilling to help protect the transmitter. The transmitter collects positional data underground and transmits this data wirelessly to the surface via a locating signal, with the locating signal being picked up by an above-ground receiver. With particularly long underground drilling projects, the battery life of the transmitter can become a limiting factor. Alternatively, particularly deep underground drilling projects, and/or drilling projects that encounter interference, can make it difficult for the above-ground receiver to pick up the locating signal from the transmitter, which in turn can interrupt the drilling project. One method to overcome these challenges is to transmit a stronger signal which can then be picked up by the above-ground receiver. However, transmitting a stronger signal typically involves consuming additional power from the battery. Increasing battery capacity can help extend the life of the battery to allow for longer drilling projects, or enable transmission of a stronger signal to enable locating in deep projects or environments with heavy interference. HDD transmitters are generally designed to be as small as possible to allow for greater maneuverability underground. Accordingly, increasing battery capacity is not typically as simple as installing a larger battery into an existing HDD transmitter design since there typically is not excess space available inside these transmitters. One approach to accommodate a larger battery is to modify the design of the HDD transmitter to increase the diameter and/or length. However, increasing the size of the transmitter introduces challenges since this would also require a larger drill housing. The size of drill housings in the HDD industry have become standardized around industry standard HDD transmitters (by way of non-limiting example, 1.25″ outer diameter and either 12″ or 19″ long) to help keep the cost of these housings more affordable. Larger, custom designed drill housings are not readily available and would increase the costs of completing drilling projects in what is a highly cost-competitive industry. In one prior art design, the batteries are received in a central cavity of the transmitter coaxially along with a dielectric antenna rod to transmit the locating signal as a dipole electromagnetic field. In such a design and given a fixed peripheral outline of the overall transmitter housing, increasing the battery length reduces the space available for the antenna rod and vice versa. In this regard, it should be appreciated that decreasing the length of the antenna rod generally results in reduced transmission efficiency, thereby demanding more battery power and potentially negating the benefit of a longer higher capacity battery. A related approach seen in the prior art resides in forming an antenna core around a tubular support to form an axial cavity such that batteries can be received in the axial cavity. Examples of this approach can be seen in U.S. Pat. Nos. 8,674,894, 9,798,033 (hereinafter, the '033 patent), U.S. Pat. No. 10,246,990 (her