US20040195008A1

US20040195008A1 - Method and apparatus for tapping a blast furnace

Info

Publication number: US20040195008A1
Application number: US10/794,575
Authority: US
Inventors: Gilbert Broom
Original assignee: Cutting Edge Technologies LLC
Current assignee: Cutting Edge Technologies LLC
Priority date: 2003-03-03
Filing date: 2004-03-03
Publication date: 2004-10-07

Abstract

A drill bit shaft member for tapping a hole in a blast furnace is disclosed. The drill bit shaft member comprises an elongate rod, a first fluid pressure inlet, a second fluid pressure inlet, a chamber in fluid communication with the first fluid pressure inlet and the second fluid pressure inlet, and an outlet in fluid communication with the chamber. A liquid and a gas are combined in the drill bit shaft member to form a mist to provide cooling for the drill bit shaft member. By cooling the drill bit shaft member, certain components that would normally be destroyed may be re-used.

Description

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Serial No. 60/451,510 for “Method and Apparatus for Boring Through a Solid Material,” filed on Mar. 3, 2003.[0001]

TECHNICAL FIELD

The present invention relates to a method and apparatus for boring through a solid body. More particularly, the invention relates to an improved drill shaft with a liquid and gas mist cooling system to allow the drill shaft to be used multiple times.

BACKGROUND ART

There are different drill bits for drilling through a variety of solid materials. Many of these drill bits are designed for particular applications. For instance, drill bits have been designed to drill through wood, metal, and concrete. In order to drill through these different materials, designers have varied the material used to produce the drill bits, the shape of the drill bits, and the speed with which the drill bit is operated.

One problem existing with many drill bits is the rate at which they will drill a hole is too slow. When the material to be drilled is difficult to penetrate, the process of boring a hole may take as long as several minutes. It is often important be able to re-use components of the drill shaft to cut down on costs and increase profits. Such is the case in drilling tap holes in metal purifying blast furnaces.

The first step in producing steel sheet, which is used in the building and construction industry, the automotive industry, the appliance industry, the electric motor industry, etc., is to produce relatively pure iron from iron ore. This process is carried out within a blast furnace. In order to maximize the productivity of a steelmaking facility, as much pure iron as possible must be produced. Many resources are expended in developing methods and procedures to increase the amount of pure iron which can be produced annually.

In developing these methods and procedures, every manufacturing variable in the blast furnace process is optimized. One of these variables is the rate at which the blast furnace can be tapped to drain molten iron from the furnace. A typical blast furnace is tapped from seven to twelve times per day seven days per week. If a drill shaft becomes damaged, the entire shaft must be replaced. The typical blast furnace tap hole takes several minutes to drill. In fact, some tap holes take as long as 15 minutes to drill.

The drilling process is also slowed by drill bit binding. Binding occurs when loosened debris created in the drilling process builds within the hole. The debris accumulates around the drill bit and freezes the drill bit within the hole preventing the drill bit from rotating within the hole.

During the drilling process, extreme heat builds because of friction and because of the external temperature. Extreme heat, such as in a steel mill, can destroy multiple drill shafts while a single hole is being drilled. Additionally, the molten steel that exits through the hole also can destroy the drill shaft.

In order to solve some of these problems, certain drill bits have been designed which have fluid passages. Pressurized air is forced through the passages toward the drill bit/solid body interface to cool the shaft assembly and blow the debris away from the drill bit and prevent binding. However, when the hole to be drilled has a substantial length, as is the case with a blast furnace tap hole, the debris continues to build because it cannot escape the hole. Additionally, the air does not provide effective heat transfer away from the drill shaft.

Prior art low-cost drill rods are described in U.S. application Ser. No. 10/133,594 for “Method and Apparatus for Boring Through a Solid Material,” now U.S. Pat. No.______ , and PCT Publication No. WO 99/39076 for “Method and Apparatus for Boring Through a Solid Material.”

The present invention is provided to solve these and other problems.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a drill bit shaft member for interconnection to a drilling apparatus. The drill bit shaft member comprises a first shaft member comprising a first elongate rod having a distal end and a proximal end. The proximal end has a first fluid pressure inlet, a second fluid pressure inlet, a chamber in fluid communication with the first fluid pressure inlet and the second fluid pressure inlet, and an outlet in fluid communication with the chamber.

It is a further object of the present invention to provide a second shaft member joined to the distal end of the first shaft member. The second shaft member comprises a second elongate rod having a fluid entrance and a fluid exit. The fluid entrance is in fluid communication with the outlet of the first shaft member and the fluid exit.

It is still a further object of the present invention to provide a tubular sleeve axially disposed around the second elongate rod to form an open volume between the second elongate rod and the tubular sleeve. A first end of the tubular sleeve is adjacent to a first end of the second elongate rod and joined to the second elongate rod to form a seal with the second elongate rod.

It is still a further object of the present invention that the second elongate rod has a first port in fluid communication with the fluid entrance of the second elongate rod and the open volume.

It is still a further object of the present invention that the second elongate rod has a second port in fluid communication with the open volume and the fluid exit of the second elongate rod.

It is still a further object of the present invention to provide a drill bit joined to a second end of the second elongate rod. The drill bit is adapted for receiving a fluid pressure from the second shaft member and delivering the fluid pressure to a drill site.

It is still a further object of the present invention that a second end of the tubular sleeve opposite the first end of the tubular sleeve is adjacent to the drill bit.

It is still a further object of the present invention that a second end of the tubular sleeve opposite the first end of the tubular sleeve abuts the drill bit.

It is still a further object of the present invention to provide an exit port in the tubular sleeve in fluid communication with the open volume.

It is still a further object of the present invention that the first fluid pressure inlet is axially disposed within the second fluid pressure inlet.

It is still a further object of the present invention that the first fluid pressure inlet delivers a liquid and the second fluid pressure inlet delivers a gas.

It is still a further object of the present invention to provide a drill bit shaft member for interconnection to a drilling apparatus. The drill bit shaft member comprises an elongate rod comprising a first fluid inlet, a second fluid inlet, a chamber in fluid communication with the first fluid inlet and the second fluid inlet. A tubular sleeve is axially disposed around the elongate rod to form an open volume between the elongate rod and the tubular sleeve. A first end of the tubular sleeve is adjacent to a first end of the elongate rod and joined to the elongate rod to form a seal. A fluid exit is in fluid communication with the chamber.

It is still a further object of the present invention that the elongate rod has a first port in fluid communication with the chamber and the open-volume.

It is still a further object of the present invention that the elongate rod has a second port in fluid communication with the open volume and the fluid exit.

It is still a further object of the present invention to provide a low-cost method for drilling a tap hole in a blast furnace. The low-cost method comprises the steps of providing a first fluid pressure source, providing a second fluid pressure source, and providing a drill shaft member comprising a first fluid pressure inlet, a second fluid pressure inlet, a chamber, and a fluid exit. The method further comprises the steps of providing a drill bit interconnected to the drill shaft member, introducing a first fluid pressure from the first fluid pressure source through the first fluid pressure inlet to the chamber, introducing a second fluid pressure from the second fluid pressure source through the second fluid pressure inlet to the chamber, and mixing the first fluid pressure and the second fluid pressure within the chamber to form a mixture of the first fluid pressure and the second fluid pressure. The mixture of the first fluid pressure and the second fluid pressure is expelled through the fluid exit, and a drilling force is provided to the drill bit.

It is still a further object of the present invention that the first fluid pressure is a liquid and the second fluid pressure is a gas.

Other advantages and aspects of the invention will become apparent upon making reference to the specification, claims, and drawings that follow.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of a drill shaft of the present invention; [0033]
FIG. 2 is a view taken along [0034] 2-2 of FIG. 1;
FIG. 3 is a cross-sectional view of a drill shaft of the present invention; [0035]
FIG. 4 is a cross-sectional view of a drill shaft of the present invention; [0036]
FIG. 5 is a view taken along [0037] 3-3 of FIG. 4;
FIG. 6 is a cross-sectional view of a drill shaft of the present invention; and, [0038]
FIG. 7 is a perspective view of a drill bit of the present invention.[0039]

DETAILED DESCRIPTION

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to embodiment illustrated. [0040]
Referring to FIG. 1, a drill [0041] bit shaft member 10 for interconnection to a drilling apparatus is shown. The drill bit shaft member 10 comprises a first shaft member 4 comprising a first elongate rod 7 having a distal end 6 and a proximal end 8. The proximal end 8 has a first fluid pressure inlet 13, a second fluid pressure inlet 15, a chamber 16 in fluid communication with the first fluid pressure inlet 13 and the second fluid pressure inlet 15, and an outlet 14 in fluid communication with the chamber 16. The first elongate rod may be an extension piece, like those set forth in U.S. application Ser. No. 10/133,594 for “Method and Apparatus for Boring Through a Solid Material,” now U.S. Pat. No.______ , which is hereby incorporated by reference herein.
The first [0042] fluid pressure inlet 13 is axially disposed within the second fluid pressure inlet 15. The first fluid pressure inlet 13 delivers a liquid and the second fluid pressure inlet 15 delivers a gas. In order to provide cooling and prevent heat damage to the drill bit shaft member 10, the liquid and the gas are delivered into the chamber 16, where they combine to form a mist, which mist can be used to cool the system during drilling. In this embodiment, the liquid is introduced into the drill bit shaft member 10 via first fluid inlet 13, which is located in the first elongate rod 7, or optionally directly into the second elongate rod 3 (this embodiment not shown).
This mist exits the [0043] chamber 16 via the outlet 14 of the first shaft member 4, and enters a second shaft member 2 that is joined to the distal end 6 of the first shaft member 4. The second shaft member 2 comprises a second elongate rod 3 having a fluid entrance 17 and a fluid exit 25. The fluid entrance 17 is in fluid communication with the outlet 14 of the first shaft member 4 and the fluid exit 25. Therefore, the mist exits through the outlet 14 and enters the second shaft member 2 via the fluid entrance 17.
A [0044] tubular sleeve 5 is axially disposed around the second elongate rod 3 to form an open volume 21 between the second elongate rod 3 and the tubular sleeve 5. A first end of the tubular sleeve 11 is adjacent to a first end of the second elongate rod 12 and joined to the second elongate rod 3 to form a seal with the second elongate rod 3. There is an exit port 20 in the tubular sleeve 5 in fluid communication with the open volume 21.
The second [0045] elongate rod 3 has a first port 19 in fluid communication with the fluid entrance 17 of the second elongate rod 3 and the open volume 21, so the mist travels from the fluid entrance 17 via the first port 19 to the open volume 21 that is created between the second elongate rod 3 and the sleeve 5. The second elongate rod 3 has a second port 23 in fluid communication with the open volume 21 and the fluid exit 25 of the second elongate rod 3, so the mist travels from the open volume 21 via the second port 23 to the fluid exit 25.
A [0046] drill bit 1 is joined to a second end 24 of the second elongate rod 3. The drill bit 1 is adapted for receiving a fluid pressure from the second shaft member 2 via the fluid exit 25 and delivering the fluid pressure to a drill site. The drill bit 1 has exit holes 27 located circumferentially around the drill bit 1, as well as optionally at the tip 29.
Another type of [0047] drill bit 1 with a smaller pilot part 28 is shown in FIG. 7. The drill bit of FIG. 7 has the exit hole 27 at the tip 29. The drill bit 1 of FIG. 7 may also have one or a plurality of raised nodules 30 that assist in efficient drilling.
A second end of the tubular sleeve [0048] 18 opposite the first end of the tubular sleeve 11 may be adjacent to the drill bit 1. In FIG. 1, the second end of the tubular sleeve 18 opposite the first end of the tubular sleeve 11 abuts the drill bit 1. The first and second ends of the tubular sleeve 11,18 may optionally be swedged (shaped like circular cones) to provide a tighter fit to the drill bit 1 and first elongate rod 7.
Referring to FIG. 3, a drill bit shaft member [0049] 310 for interconnection to a drilling apparatus is shown. The drill bit shaft member 310 comprises an elongate rod 303 comprising a first fluid inlet 313, a second fluid inlet 315, a chamber 331 in fluid communication with the first fluid inlet 313 and the second fluid inlet 315. The first fluid pressure inlet 313 is axially disposed within the second fluid pressure inlet 315. The first fluid pressure inlet 313 delivers a liquid and the second fluid pressure inlet 315 delivers a gas. In order to provide cooling and prevent heat damage to the drill bit shaft member 310, the liquid and the gas are mixed in the chamber 331 to form a mist that cools the system during drilling.
A [0050] tubular sleeve 305 is axially disposed around the elongate rod 303 to form an open volume 321 between the elongate rod 303 and the tubular sleeve 305. A first end of the tubular sleeve 308 is adjacent to a first end of the elongate rod 309 and joined to the elongate rod 303 to form a seal.
A [0051] fluid exit 333 is in fluid communication with the chamber 331. There is an exit port 337 in the tubular sleeve 305 in fluid communication with the open volume 321. A first port 334 may be in fluid communication with the chamber 331 and the open volume 321. A second port 335 may be in fluid communication with the open volume 321 and the fluid exit 333. Allowing mist to flow in the open volume 321 greatly reduces the heat damage to the sleeve 305 and the elongate rod 303.
The liquid and the gas are directed into the drill bit shaft member [0052] 310 via the first and second fluid inlets 313, 315, and combined in the chamber 331 to form a mist. The first and second fluid inlets 313, 315 may be located as shown, or in an extension piece (this embodiment is not shown). Instead of using the first and second ports 334, 335 to distribute the mist, the embodiment shown in FIG. 3 may optionally be made without the first and second ports 334, 335 (this embodiment is not shown). This is because the chamber 331 extends the length of the elongate rod 303, in other words, the elongate rod 303 is a hollow tube. This allows the mist to flow freely through elongate rod 303 and via the fluid exit 333 to a drill bit 301. The drill bit 301 has exit holes 327 located circumferentially around the bit as well as optionally at the tip 329.
The elongate rod may take the form of a solid rod or a hollow tube. The second [0053] elongate rod 3 shown in FIG. 1 is an example of the solid rod type, as can be seen from the cross-section shown in FIG. 2. The elongate rod 303 shown in FIG. 3 is an example of the hollow tube rod type. Depending upon the drilling situation if the hollow tube rod type is chosen, thicker-walled tubing must be used to provide the proper strength for the rod. The tubular sleeve 5, 305 is typically a hollow tube, but may vary in thickness according to the requirements of each job.
The liquid and the gas are both pressurized to force the mist to flow through the drill [0054] bit shaft member 10, 310. The flow rate and pressure of the liquid and the gas are adjustable based on the heat transfer requirements for each job. If more heat needs to be removed from the drill bit shaft member 10, 310, the flow rates of the liquid and the gas can be increased accordingly. It has been found that, generally, the liquid pressure needs to be at least 10 psi greater than the gas pressure. The ratio of liquid pressure to gas pressure, as well as liquid flow rate to gas flow rate, can be optimized to produce a desired mist consistency. In many locations, water pressure provided from a regular spigot and gas pressure provided by a portable compressor is sufficient to produce an adequate mist. Much higher pressures can also be used to produce an adequate mist.
One of the novel aspects of the present invention is that the liquid and the gas are combined in the drill [0055] bit shaft member 10, 310, itself, instead of prior to entering the drill bit shaft member 10, 310 as a premixed mist. One of the beneficial aspects of this method is that the mist should not flow back into the hammer or drill mechanism. Flow back is prevented by mixing the liquid and the gas in the drill bit shaft member 10, 310. Others have attempted to use water and air streams, but have combined them prior to entering the drill rod. In those prior attempts, the water flows through the hammer itself and causes corrosion and ice blockages during the winter. In many situations, the chosen liquid is water and the chosen gas is air. Other possible liquids that may be utilized in the present invention include water-based coolants. Other possible gases that may be utilized in the present invention include nitrogen and carbon dioxide. The choice of liquid and gas components is dependent upon their availability, as well as the situation in which the drill bit shaft member 10, 310 may be used. In some situations, it may be dangerous to use compressed air because of the oxygen content. In those situations, nitrogen gas may be used instead.
The mist acts as a heat carrier by absorbing heat from the drill [0056] bit shaft member 10, 310 and carrying it away from the drill bit shaft member 10, 310 when it exits through either the drill bit 1, 301 or the exit ports 27, 327 located on the sleeve 5, 305. The quantity of heat removed from the system is dependent upon the component chosen for the gas and liquid, as well as the flow rates of the components. An air and water mist is an ideal mist because of its ability to carry and remove heat from the system. Most of the heat is removed from the system by the liquid component, such as water. Water has two important functions for removing heat from the system. First, as a liquid and gas, water has a specific heat capacity for absorbing heat. Second, a large amount of heat is absorbed in the transformation of water from liquid to gas. The heat that is absorbed is the heat of vaporization. These two heat-absorbing functions, when combined, can remove a large amount of heat from the system. These values will vary according to the pressure of the system.
Not only is an air and water mist excellent for removing heat from the system, but it is inexpensive and readily available in most locations where the present invention may be utilized. One location that the present invention may be utilized is in steel mills. Steel mills generally have either compressed air lines or portable compressors, as well as water sources from a spigot. The water pressure can be increased as needed with a pump. [0057]
Another embodiment of the present invention for protecting the drill rod and interior shaft from heat damage consists of utilizing an insulating layer. Referring to FIG. 4, a drill bit for boring a hole through a solid body is illustrated. The [0058] drill bit 401 is shown joined to an interior shaft 403 and abutting a sleeve 405. The interior shaft may take the form of a solid rod or hollow tube. Depending upon the drilling situation if tubing is chosen, thicker-walled tubing must be used to provide proper strength. The outer sleeve is typically a hollow tube, but may vary in thickness according to each job. The bit 401 typically will attach to the interior shaft 403 and abut the sleeve 405. Between the interior shaft 403 and the sleeve 405, a paper pulp material 441 is placed for insulation. Paper pulp material such as cardboard may be utilized as an efficient insulator because its thermal conductivity is 0.07 W/mK whereas medium carbon steel is approximately 51.9 W/mK. This insulation prevents excessive heat from traveling from the sleeve 405 to the interior shaft 403 during drilling.
Paper pulp materials are ideal for drill rod applications. As evident from its thermal conductivity, cardboard is an inexpensive insulating material that will not conduct excessive heat as steel does. Paper pulp material is readily available, comes in various sizes and can also be customized for unique applications. For example, cardboard can be preformed to precisely fit around the [0059] interior shaft 403 but still be small enough to fit inside the sleeve 405. Not only is the material easily shaped, but it is inexpensive. Other insulators, such as polycarbonate may be utilized as well. The above embodiments, the misting system and the cardboard embodiment, may optionally be combined.
Additionally, the drill shaft utilized in the misting embodiment and cardboard embodiment may consist of extensions. Referring to FIG. 5, a [0060] base unit 551, an extension unit 553, and an end unit 555 may be utilized. The drill shaft 500 may exist with any number of extensions, or no extensions, as required for specific uses. In FIG. 6, notice that only the end unit 555 has an exterior sleeve 505 and an interior shaft 503. This is because usually only the end of the drill shaft is so severely damaged that it may not be re-used. Therefore, by having the end unit sleeved, minimal material is discarded after each use when the sleeve is destroyed. Also notice that the ends of the exterior sleeve are swedged to provide a tighter seal at the sleeve/drill bit interface and the sleeve/extension or base interface. The sleeve merely abuts the other pieces at these interfaces and is held in place by compression when the drill bit is attached.
When utilizing a mist, the first and second [0061] fluid inlets 13, 313, 15, 315 may extend through the entire drill bit shaft member 10, 310, or only partially. Depending on external temperatures, and heat transfer requirements, it may be desired to combine the liquid and gas to form the mist at a specific portion of the shaft.
Additional improvements have been made to prevent damage to the drill [0062] bit shaft member 10, 310 of the present invention. For example, typically, the tubular sleeve 5, 305 was significantly smaller than the drill bit 1, 301 head. This created a problem because it allowed a large space for molten steel to flow when the drill hole was finished but the drill bit shaft member 10, 310 had not yet been removed. By increasing the size of the sleeve 5, 305, so that it is only slightly smaller than the drill bit, the volume of molten steel that flows around the drill bit shaft member 10, 310 is limited, thus minimizing damage. For example, the sleeve 5, 305 could be 0-20% smaller, or more preferably 0-10% smaller than the drill bit 1, 301 head, or any range or combination of ranges therein.
Another improvement was made by increasing the length of the [0063] drill bit 1, 301. As described above, when the hole is complete, molten steel flows around the drill bit shaft member 10, 310. By lengthening the bit 1, 301, which is usually destroyed during each use, the remaining pieces of the drill bit shaft member 10, 310 may sometimes be saved and re-used.
Another aspect of the present invention is that the interior [0064] elongate rod 3, 303 is not welded to the sleeve 5, 305. Typically, the interior elongate rod 3, 303 was welded to the sleeve 5, 305 to provide a permanent leak-proof fit. By allowing the sleeve 5, 305 to be removed from the interior elongate rod 3, 303, the interior elongate rod 3, 303 may be re-used while the sleeve 5, 305 may be discarded.
It is still a further object of the present invention to provide a low-cost method for drilling a tap hole in a blast furnace. The low-cost method comprises the steps of providing a first fluid pressure source, providing a second fluid pressure source, and providing a [0065] drill shaft member 10 comprising a first fluid pressure inlet 13, a second fluid pressure inlet 15, a chamber 16, and a fluid exit 25. The method further comprises the steps of providing a drill bit 1 interconnected to the drill shaft member 10, introducing a first fluid pressure from the first fluid pressure source through the first fluid pressure inlet 13 to the chamber 16, introducing a second fluid pressure from the second fluid pressure source through the second fluid pressure inlet 15 to the chamber 16, and mixing the first fluid pressure and the second fluid pressure within the chamber 16 to form a mixture of the first fluid pressure and the second fluid pressure. The mixture of the first fluid pressure and the second fluid pressure is expelled through the fluid exit 25, and a drilling force is provided to the drill bit 1. The first fluid pressure inlet 13 may be axially disposed within the second fluid pressure inlet 15. The first fluid pressure may be a liquid and the second fluid pressure may be a gas.
Several alternative embodiments have been described and illustrated. A person of ordinary skilled in the art would appreciate that the features of the individual embodiments, and the possible combinations and variations of the components. A person of ordinary skill in the art would further appreciate that any of the embodiments could be provided in any combination with the other embodiments disclosed herein. Further, the terms “first,”“second,” “proximal,” “distal,” etc. are used for illustrative purposes only and are not intended to limit the embodiments in any way, and the term “plurality” as used herein is intended to indicate any number greater than one, either disjunctively or conjunctively as necessary, up to an infinite number. [0066]
While specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention and the scope of protection is only limited by the scope of the accompanying claims. [0067]

Claims

We claim:

1. A drill bit shaft member for interconnection to a drilling apparatus, the drill bit shaft member comprising:

a first shaft member comprising a first elongate rod having a distal end and a proximal end, the proximal end having a first fluid pressure inlet, a second fluid pressure inlet, a chamber in fluid communication with the first fluid pressure inlet and the second fluid pressure inlet, and an outlet in fluid communication with the chamber.

2. The drill bit shaft member of claim 1 further comprising:

a second shaft member joined to the distal end of the first shaft member, the second shaft member comprising a second elongate rod having a fluid entrance and a fluid exit, the fluid entrance in fluid communication with the outlet of the first shaft member and the fluid exit.

3. The drill bit shaft member of claim 2 further comprising:

a tubular sleeve axially disposed around the second elongate rod to form an open volume between the second elongate rod and the tubular sleeve, a first end of the tubular sleeve adjacent to a first end of the second elongate rod and joined to the second elongate rod to form a seal with the second elongate rod.

4. The drill bit shaft member of claim 3 wherein the second elongate rod has a first port in fluid communication with the fluid entrance of the second elongate rod and the open volume.

5. The drill bit shaft member of claim 4 wherein the second elongate rod has a second port in fluid communication with the open volume and the fluid exit of the second elongate rod.

6. The drill bit shaft member of claim 5 further comprising:

a drill bit joined to a second end of the second elongate rod, the drill bit adapted for receiving a fluid pressure from the second shaft member and delivering the fluid pressure to a drill site.

7. The drill bit shaft member of claim 6, wherein a second end of the tubular sleeve opposite the first end of the tubular sleeve is adjacent to the drill bit.

8. The drill bit shaft member of claim 7 wherein the second end of the tubular sleeve abuts the drill bit.

9. The drill bit shaft member of claim 8 further comprising:

an exit port in the tubular sleeve in fluid communication with the open volume.

10. The drill bit shaft member of claim 1 wherein the first fluid pressure inlet is axially disposed within the second fluid pressure inlet.

11. The drill bit shaft member of claim 1 wherein the first fluid pressure inlet delivers a liquid and the second fluid pressure inlet delivers a gas.

12. A drill bit shaft member for interconnection to a drilling apparatus, the drill bit shaft member comprising:

an elongate rod comprising a first fluid inlet, a second fluid inlet, a chamber in fluid communication with the first fluid inlet and the second fluid inlet, a tubular sleeve axially disposed around the elongate rod to form an open volume between the elongate rod and the tubular sleeve, a first end of the tubular sleeve adjacent to a first end of the elongate rod and joined to the elongate rod to form a seal, and a fluid exit in fluid communication with the chamber.

13. The drill bit shaft member of claim 12 wherein the elongate rod has a first port in fluid communication with the chamber and the open volume.

14. The drill bit shaft member of claim 13 wherein the elongate rod has a second port in fluid communication with the-open volume and the fluid exit.

15. The drill bit shaft member of claim 14 further comprising:

an exit port in the tubular sleeve in fluid communication with the open volume.

16. The drill bit shaft member of claim 12 wherein the first fluid pressure inlet is axially disposed within the second fluid pressure inlet.

17. The drill bit shaft member of claim 12 wherein the first fluid pressure inlet delivers a liquid and the second fluid pressure inlet delivers a gas.

18. A low-cost method for drilling a tap hole in a blast furnace, the low-cost method comprising the steps of:

providing a first fluid pressure source;

providing a second fluid pressure source;

providing a drill shaft member comprising a first fluid pressure inlet, a second fluid pressure inlet, a chamber, and a fluid exit;

providing a drill bit interconnected to the drill shaft member;

introducing a first fluid pressure from the first fluid pressure source through the first fluid pressure inlet to the chamber;

introducing a second fluid pressure from the second fluid pressure source through the second fluid pressure inlet to the chamber;

mixing the first fluid pressure and the second fluid pressure within the chamber to form a mixture of the first fluid pressure and the second fluid pressure;

expelling the mixture of the first fluid pressure and the second fluid pressure through the fluid exit; and,

providing a drilling force to the drill bit.

19. The low-cost method of claim 18 wherein the first fluid pressure inlet is axially disposed within the second fluid pressure inlet.

20. The low-cost method of claim 18 wherein the first fluid pressure is a liquid and the second fluid pressure is a gas.