EP2310620A2 - An arrangement and a method for monitoring an air flow in a drill rig - Google Patents

An arrangement and a method for monitoring an air flow in a drill rig

Info

Publication number
EP2310620A2
EP2310620A2 EP09746914A EP09746914A EP2310620A2 EP 2310620 A2 EP2310620 A2 EP 2310620A2 EP 09746914 A EP09746914 A EP 09746914A EP 09746914 A EP09746914 A EP 09746914A EP 2310620 A2 EP2310620 A2 EP 2310620A2
Authority
EP
European Patent Office
Prior art keywords
air flow
compressor
drill bit
air
pressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP09746914A
Other languages
German (de)
French (fr)
Other versions
EP2310620B1 (en
Inventor
Per Krainer
Deyi Jiao
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Epiroc Rock Drills AB
Epiroc Drilling Solutions LLC
Original Assignee
Atlas Copco Rock Drills AB
Atlas Copco Drilling Solutions LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from PCT/US2008/006075 external-priority patent/WO2009139743A1/en
Application filed by Atlas Copco Rock Drills AB, Atlas Copco Drilling Solutions LLC filed Critical Atlas Copco Rock Drills AB
Publication of EP2310620A2 publication Critical patent/EP2310620A2/en
Application granted granted Critical
Publication of EP2310620B1 publication Critical patent/EP2310620B1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
    • E21B21/08—Controlling or monitoring pressure or flow of drilling fluid, e.g. automatic filling of boreholes, automatic control of bottom pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C13/00—Adaptations of machines or pumps for special use, e.g. for extremely high pressures
    • F04C13/008—Pumps for submersible use, i.e. down-hole pumping
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2240/00—Components
    • F04C2240/80—Other components
    • F04C2240/81—Sensor, e.g. electronic sensor for control or monitoring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/40—Conditions across a pump or machine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/08—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by varying the rotational speed

Definitions

  • An arrangement and a method for monitoring an air flow in a drill rig An arrangement and a method for monitoring an air flow in a drill rig.
  • the present invention relates to an arrangement in a drill rig and to a method of detecting a reduced air flow through a flushing hole in a drill bit.
  • Drill rigs in different sizes are frequently used in constructional work to drill holes in rocks.
  • the drill rig comprises a rock drilling machine with a drill bit adapted for the specific conditions of the rock and used to penetrate the rock, and chip away the fractured rocks.
  • the penetration force is generated by either a high level feed force or percussive wave forms.
  • the rotation torque generated by a rotation motor will shear off the fractured rock.
  • a drill bit comprises flushing holes and compressed air is arranged to flow out through the holes during drilling.
  • the flow of air is however stopped if the flushing holes get plugged by mud or if fine cuttings are compacted into the flushing holes.
  • the ground condition where the rock drill works varies widely and the existence of mud in the ground substantially increases the risk of plugged holes.
  • the drill bit is plugged by impacting the fine cuttings into the flushing hole.
  • the flushing holes are plugged, the drill bit gets stuck and then the drilling is completely stopped. Then, the drill hole must be cleaned which takes a considerable time. It may involve pulling out the whole drill string. Consequently, it is important to ensure a continuous air flow through the flushing holes of the drill bit.
  • a commonly used method of detecting a reduced or stopped air flow in the flushing holes of a drill bit is to arrange an air flow monitoring device e.g. a venturi flow nozzle in the air flow path downstream a compressor.
  • a low differential pressure is generated by such a device, in the range of a few psi while the working pressure is much higher. This normally means a differential pressure of less than 5 psi.
  • a certain differential pressure indicates a normal air flow through the holes. When the certain differential pressure disappears, it indicates a stopped air flow.
  • a mechanical or electrical device comprising a switch is used to detect a differential pressure and to send out a signal to a control unit to e.g. reverse the feed of air and stop the drilling.
  • the creation and detection of a differential pressure puts demand on high sensitivity and high accuracy since the device used is working in a comparatively very high pressure environment. !
  • prior art arrangements require a detection device having a very high sensitivity for detecting small pressure changes in a relatively high pressure environment.
  • This kind of electrical and/or mechanical devices are very expensive and have high maintenance cost.
  • prior art monitoring devices give rise to a pressure drop in the air flow path which will have a negative impact on the air flow out through the flushing holes in the drill bit. It also has a negative impact on energy consumption.
  • the aim of the invention is to remedy the above mentioned drawbacks with air flow monitoring device as mentioned above.
  • an arrangement of the kind in question has the specific features that it comprises a rock drill rig comprising an air inlet valve arranged in a flow path upstream to a displacement compressor that is used for supplying an air flow to at least one flushing hole in the surface of a drill bit.
  • the drill rig further comprises an air regulator arranged to regulate the system pressure in an air flow path downstream the compressor and means for detecting a changed flow of air through the at least one flushing hole in the surface of the drill bit.
  • the detecting means comprises a pressure sensor arranged between the air regulator and the inlet valve and the sensor is adapted to measure the reduced system pressure.
  • the solution according to the invention makes it possible to arrange a point for monitoring the flow of air through the flushing holes in the drill bit upstream of the compressor. Through measuring the reduced system pressure and knowing the inlet valve, the air flow rate through the system is indirectly monitored.
  • a pressure regulator comprises an unloader cylinder which senses the reduced system pressure caused by flow changes in the system.
  • the pressure regulator has a wide pressure changing range and this is why we use this feature for the air sensing.
  • the inlet valve is arranged to work against atmospheric pressure and the inlet valve opening area is inversely proportional to the differential pressure.
  • the pressure changes at the regulator is inversely proportional to the air flow rate downstream the compressor. Accordingly, the monitored reduced system pressure is inversely proportional to the system air flow rate.
  • the reduced system pressure is around 0-40 psi while the air system pressure is between 100- 150 psi.
  • the solution according to the invention provides a measurement resolution and an accuracy, which is extremely high compared to prior art arrangements.
  • the pressure between the inlet valve and the compressor is a negative pressure and measuring a negative pressure demands a more complicated and expensive equipment.
  • the solution according to the invention makes it possible to use relatively inexpensive standard sensors because resolution and accuracy of the sensor is not required to achieve same or better performance for the same air monitoring functions. This results in an arrangement having better performance at a lower price since pressure sensors provide reliable measuring results, and are less complex components that are readily available and easy to install.
  • a further advantage is that the amount of components is reduced compared to prior art solutions e.g. there is no device giving rise to a pressure drop in the air flow path. This has a positive impact on the energy consumption.
  • the displacement compressor is a screw compressor or any type of displacement compressor.
  • the displacement compressor is a rotary compressor with constant rotation speed.
  • the displacement compressor (32) is a rotary compressor with variable rotation speed.
  • a method of the kind in question has the specific features that it comprises detecting an air flow rate through at least one flushing hole in a front surface of a drilling bit arranged in a rock drill rig.
  • the rock drill rig comprises an inlet valve arranged upstream a displacement compressor that is used for supplying an air flow to the at least one flushing hole in the drill bit.
  • the drill rig further comprises an air pressure regulator arranged to regulate the system pressure in the air flow path downstream the compressor.
  • the method comprises measuring a reduced system pressure between the regulator and the inlet valve. Further, the method comprises detecting the air flow rate through the drill bit based on the fact that the measured reduced system pressure is inversely proportional to the air flow rate. This is based on a constant rotation speed of the compressor and the fact that the system air flow is dependent on the compressor speed rotation.
  • An embodiment is a method comprising comparing the determined air flow rate with a predetermined value. If the determined air flow rate is lower than the predetermined value, send a signal to a control unit to reduce the speed of the drill bit or to stop drilling. Further, if the determined air flow rate is equal or higher than the predetermined value, send a signal to the control unit to continue drilling. The method is repeated at predetermined intervals in order to control the flushing during drilling.
  • Figure 1 is a drill rig in which the claimed arrangement is used
  • Figure 2 is a perspective view of a drill bit
  • Figure 3 is the claimed arrangement schematically disclosed
  • Figure 4 is a diagram showing the reduced system pressure changes (denoted unloader pressure) versus differential pressure generated by venture flow nozzle.
  • FIG. 1 a surface rock drill rig 10 is illustrated.
  • the rig 10 is used for hole drilling in different types of constructional or mining work.
  • the rig 10 comprises a rig body 11 that comprises machinery for enabling transport of the rig, as well as for providing the required power to conduct the drilling and a displacement compressor (not shown).
  • the drill is placed in the outer end of an elongated arm 12 that extend forward from the rig body 11.
  • the arm is manoeuvrable to be easily movable to the intended position of the hole.
  • a drill bit 20, illustrated in Figure 2 is used for penetrating the rock and chip away the fractured rocks.
  • the front surface 21 of the drill bit 20 is provided with a number of drill elements 22 used for penetrating the rock.
  • the front surface is furthermore provided with four flushing holes 23. Compressed air, provided from the displacement compressor in the rig body 11 , is flowing out from the flushing holes 23 in order to blow the rock cuttings away and clean the surface of the rock. This ensures that the drill bit 20 always is in contact with fresh and solid rock surface in order to keep the drilled hole free from already cut rock.
  • FIG. 3 is a part of a drill rig air system schematically disclosed.
  • the system comprises an air inlet flow path 30 through which air to a compressor 32, powered by a power source M, is lead via an inlet valve 31.
  • Compressed air from the compressor 32 is passed on to a pressure vessel 33.
  • Air is fed from the pressure vessel 33 via an air flow path 34 to the drill bit 20 where it exits the bit via the flushing holes 23.
  • An air regulator 36 is arranged to regulate the inlet air valve 31 to regulate the air system pressure which the compressor produces in the air flow path 34 downstream the compressor.
  • the inlet valve 31 is used for regulating the quantity of air supplied to the compressor 32 in order to avoid the system pressure from rising when the air flow through the flushing holes 23 in the drill bit 20 are plugged.
  • the system further comprises a pressure sensor arranged between the regulator 36 and the inlet valve 31.
  • the pressure sensor is adapted to measure the reduced system pressure and to send a corresponding signal to a control unit 37.
  • the air flow rate through the drill bit 20 is determined based on the fact that the measured reduced system pressure is inversely proportional to the air flow rate.
  • the method is based on a desired rotation speed in each working point.
  • the speed of the drill bit is reduced and/or the drilling is stopped.
  • Figure 4 is a chart showing the result of a test done on a surface rock drill rig comprising a venturi flow nozzle.
  • the diagram shows the relationship between the reduced system pressure (denoted unloader pressure) and the air flow rate.
  • the flow rate is indicated by differential pressure created by air flow through the venture flow nozzle device.
  • the differential pressure is proportional to the flow rate.
  • the reduced system pressure When the air flow reaches zero, the reduced system pressure reaches its highest level. This reduced system pressure is about 30% of the system pressure and is much higher pressure than commonly used venture tube generated differential pressure. The difference between the full flow and zero flow conditions is very easily detected by monitoring the reduced system pressure changes. An economical and simple pressure sensor can so be used for detecting the air flow status.
  • the reduced system pressure is highest when the differential pressure is close to zero i.e. when the air flow through the flushing holes is close to zero.
  • the reduced system pressure is lowest when the differential pressure is highest i.e. when the air flow through the flushing holes is full and the inlet valve is fully open.
  • the air regulator 36 closes the inlet air valve 31 to prevent the system pressure from going up. This is achieved in that the inlet valve is controlled by the reduced system pressure.
  • the pressure sensor is measuring the reduced air system pressure and thereby indirectly monitoring the flow rate of air through the flushing holes.
  • both pressure and compressor speed rotation are considered and therefore the air flow rate is completely controlled.
  • a consequence of the present invention is that with a given pressure in the air inlet path and varying the compressor speed rotation, the air flow rate will vary linearly with the compressor speed rotation.

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Earth Drilling (AREA)

Abstract

The present invention relates to an arrangement in a rock drill rig 10 comprising an inlet valve 31 arranged upstream a displacement compressor 32 that is used for supplying an air flow 34 to at least one flushing hole 23 in the surface of a drill bit 20. The drill rig 10 further comprising an regulator 35 arranged to regulate the system pressure in the air flow path 34 downstream the compressor and means for detecting an flow of air through the at least one flushing hole 23 in the surface of the drill bit. The detecting means comprises a pressure sensor 36, arranged between the air regulator 35 and the inlet valve 31, adapted to measure the reduced system pressure.

Description

An arrangement and a method for monitoring an air flow in a drill rig.
The present application claims the benefit of International Patent Application PCT/US2008/006075, filed in the United States Receiving Office on May 13, 2008, pursuant to 35 U.S.C. Section 365.
TECHNICAL FIELD
The present invention relates to an arrangement in a drill rig and to a method of detecting a reduced air flow through a flushing hole in a drill bit.
BACKGROUND ART
Drill rigs in different sizes are frequently used in constructional work to drill holes in rocks. The drill rig comprises a rock drilling machine with a drill bit adapted for the specific conditions of the rock and used to penetrate the rock, and chip away the fractured rocks. The penetration force is generated by either a high level feed force or percussive wave forms. The rotation torque generated by a rotation motor will shear off the fractured rock.
In surface rock drilling processes, it is standard practice to use compressed air to blow away the rock cuttings and clean the surface of the rock to ensure that the drill bit always is in contact with a fresh and solid rock surface. If the cuttings were not cleaned away, the drill bit would penetrate the cuttings and further break down the cuttings into smaller sizes. This secondary breakage is not wanted because of the considerable quantity of waste energy and reduced drilling efficiency. The accumulation of the cuttings will furthermore resist the rotation of the drill bit and eventually jam the drill bit to stop.
A drill bit comprises flushing holes and compressed air is arranged to flow out through the holes during drilling. The flow of air is however stopped if the flushing holes get plugged by mud or if fine cuttings are compacted into the flushing holes. The ground condition where the rock drill works varies widely and the existence of mud in the ground substantially increases the risk of plugged holes. When the ground is soft while drilling rate is so fast that the air provided is not sufficient to clean the cuttings away, the drill bit is plugged by impacting the fine cuttings into the flushing hole. When the flushing holes are plugged, the drill bit gets stuck and then the drilling is completely stopped. Then, the drill hole must be cleaned which takes a considerable time. It may involve pulling out the whole drill string. Consequently, it is important to ensure a continuous air flow through the flushing holes of the drill bit.
A commonly used method of detecting a reduced or stopped air flow in the flushing holes of a drill bit is to arrange an air flow monitoring device e.g. a venturi flow nozzle in the air flow path downstream a compressor. A low differential pressure is generated by such a device, in the range of a few psi while the working pressure is much higher. This normally means a differential pressure of less than 5 psi. A certain differential pressure indicates a normal air flow through the holes. When the certain differential pressure disappears, it indicates a stopped air flow. A mechanical or electrical device comprising a switch is used to detect a differential pressure and to send out a signal to a control unit to e.g. reverse the feed of air and stop the drilling. The creation and detection of a differential pressure puts demand on high sensitivity and high accuracy since the device used is working in a comparatively very high pressure environment. !
>
Accordingly, prior art arrangements require a detection device having a very high sensitivity for detecting small pressure changes in a relatively high pressure environment. This kind of electrical and/or mechanical devices are very expensive and have high maintenance cost.
Furthermore, prior art monitoring devices give rise to a pressure drop in the air flow path which will have a negative impact on the air flow out through the flushing holes in the drill bit. It also has a negative impact on energy consumption.
Thus, there are needs to improve arrangements and methods for detecting a reduced, or stopped, air flow through the flushing holes of a drill bit in a rock drill rig.
I
SUMMARY OF THE INVENTION
The aim of the invention is to remedy the above mentioned drawbacks with air flow monitoring device as mentioned above.
The above problem is according to the first aspect of the invention solved in that an arrangement of the kind in question has the specific features that it comprises a rock drill rig comprising an air inlet valve arranged in a flow path upstream to a displacement compressor that is used for supplying an air flow to at least one flushing hole in the surface of a drill bit. The drill rig further comprises an air regulator arranged to regulate the system pressure in an air flow path downstream the compressor and means for detecting a changed flow of air through the at least one flushing hole in the surface of the drill bit. The detecting means comprises a pressure sensor arranged between the air regulator and the inlet valve and the sensor is adapted to measure the reduced system pressure.
The solution according to the invention makes it possible to arrange a point for monitoring the flow of air through the flushing holes in the drill bit upstream of the compressor. Through measuring the reduced system pressure and knowing the inlet valve, the air flow rate through the system is indirectly monitored.
Generally, a pressure regulator comprises an unloader cylinder which senses the reduced system pressure caused by flow changes in the system. The pressure regulator has a wide pressure changing range and this is why we use this feature for the air sensing.
The inlet valve is arranged to work against atmospheric pressure and the inlet valve opening area is inversely proportional to the differential pressure.
Knowing the reduced system pressure and the characteristic of the inlet valve leads to the pressure between the inlet valve and the compressor.
The pressure changes at the regulator is inversely proportional to the air flow rate downstream the compressor. Accordingly, the monitored reduced system pressure is inversely proportional to the system air flow rate.
The reduced system pressure is around 0-40 psi while the air system pressure is between 100- 150 psi. The solution according to the invention provides a measurement resolution and an accuracy, which is extremely high compared to prior art arrangements.
Additionally, it is practically easier to measure the reduced system pressure between the regulator and the inlet valve than between the inlet valve and the compressor. Further, the pressure between the inlet valve and the compressor is a negative pressure and measuring a negative pressure demands a more complicated and expensive equipment.
The solution according to the invention makes it possible to use relatively inexpensive standard sensors because resolution and accuracy of the sensor is not required to achieve same or better performance for the same air monitoring functions. This results in an arrangement having better performance at a lower price since pressure sensors provide reliable measuring results, and are less complex components that are readily available and easy to install.
A further advantage is that the amount of components is reduced compared to prior art solutions e.g. there is no device giving rise to a pressure drop in the air flow path. This has a positive impact on the energy consumption.
According to one embodiment of the invention, the displacement compressor is a screw compressor or any type of displacement compressor.
According to one embodiment of the invention, the displacement compressor is a rotary compressor with constant rotation speed.
According to one embodiment of the invention, the displacement compressor (32) is a rotary compressor with variable rotation speed.
The above problem is according to the second aspect of the invention solved in that a method of the kind in question has the specific features that it comprises detecting an air flow rate through at least one flushing hole in a front surface of a drilling bit arranged in a rock drill rig. The rock drill rig comprises an inlet valve arranged upstream a displacement compressor that is used for supplying an air flow to the at least one flushing hole in the drill bit. The drill rig further comprises an air pressure regulator arranged to regulate the system pressure in the air flow path downstream the compressor. The method comprises measuring a reduced system pressure between the regulator and the inlet valve. Further, the method comprises detecting the air flow rate through the drill bit based on the fact that the measured reduced system pressure is inversely proportional to the air flow rate. This is based on a constant rotation speed of the compressor and the fact that the system air flow is dependent on the compressor speed rotation.
An embodiment is a method comprising comparing the determined air flow rate with a predetermined value. If the determined air flow rate is lower than the predetermined value, send a signal to a control unit to reduce the speed of the drill bit or to stop drilling. Further, if the determined air flow rate is equal or higher than the predetermined value, send a signal to the control unit to continue drilling. The method is repeated at predetermined intervals in order to control the flushing during drilling.
By considering a variable rotational speed of a compressor, the solution according to the invention teaches the air flow in other working points.
BRIEF DESCRIPTION OF THE DRAWING
One embodiment of the present claimed invention is schematically illustrated in the appended figure, in which:
Figure 1 is a drill rig in which the claimed arrangement is used;
Figure 2 is a perspective view of a drill bit, and
Figure 3 is the claimed arrangement schematically disclosed,
Figure 4 is a diagram showing the reduced system pressure changes (denoted unloader pressure) versus differential pressure generated by venture flow nozzle.
DESCRIPTION OF ALTERNATIVE EMBODIMENTS
In Figure 1 a surface rock drill rig 10 is illustrated. The rig 10 is used for hole drilling in different types of constructional or mining work. The rig 10 comprises a rig body 11 that comprises machinery for enabling transport of the rig, as well as for providing the required power to conduct the drilling and a displacement compressor (not shown). The drill is placed in the outer end of an elongated arm 12 that extend forward from the rig body 11. The arm is manoeuvrable to be easily movable to the intended position of the hole.
A drill bit 20, illustrated in Figure 2, is used for penetrating the rock and chip away the fractured rocks. The front surface 21 of the drill bit 20 is provided with a number of drill elements 22 used for penetrating the rock. The front surface is furthermore provided with four flushing holes 23. Compressed air, provided from the displacement compressor in the rig body 11 , is flowing out from the flushing holes 23 in order to blow the rock cuttings away and clean the surface of the rock. This ensures that the drill bit 20 always is in contact with fresh and solid rock surface in order to keep the drilled hole free from already cut rock.
Figure 3 is a part of a drill rig air system schematically disclosed. The system comprises an air inlet flow path 30 through which air to a compressor 32, powered by a power source M, is lead via an inlet valve 31. Compressed air from the compressor 32 is passed on to a pressure vessel 33. Air is fed from the pressure vessel 33 via an air flow path 34 to the drill bit 20 where it exits the bit via the flushing holes 23. An air regulator 36 is arranged to regulate the inlet air valve 31 to regulate the air system pressure which the compressor produces in the air flow path 34 downstream the compressor.
The inlet valve 31 is used for regulating the quantity of air supplied to the compressor 32 in order to avoid the system pressure from rising when the air flow through the flushing holes 23 in the drill bit 20 are plugged.
The system further comprises a pressure sensor arranged between the regulator 36 and the inlet valve 31. the pressure sensor is adapted to measure the reduced system pressure and to send a corresponding signal to a control unit 37. The air flow rate through the drill bit 20 is determined based on the fact that the measured reduced system pressure is inversely proportional to the air flow rate.
Where the displacement compressor 32 is a rotary compressor with variable rotation speed, the method is based on a desired rotation speed in each working point.
If the determined air flow rate is lower than a predetermined value, the speed of the drill bit is reduced and/or the drilling is stopped.
If the determined air flow rate is equal or higher than a predetermined value, the drilling is continued.
Figure 4 is a chart showing the result of a test done on a surface rock drill rig comprising a venturi flow nozzle. The diagram shows the relationship between the reduced system pressure (denoted unloader pressure) and the air flow rate. The flow rate is indicated by differential pressure created by air flow through the venture flow nozzle device. The differential pressure is proportional to the flow rate.
When the air flow reaches zero, the reduced system pressure reaches its highest level. This reduced system pressure is about 30% of the system pressure and is much higher pressure than commonly used venture tube generated differential pressure. The difference between the full flow and zero flow conditions is very easily detected by monitoring the reduced system pressure changes. An economical and simple pressure sensor can so be used for detecting the air flow status.
The reduced system pressure is highest when the differential pressure is close to zero i.e. when the air flow through the flushing holes is close to zero.
The reduced system pressure is lowest when the differential pressure is highest i.e. when the air flow through the flushing holes is full and the inlet valve is fully open.
Accordingly, if the air flow through the flushing holes 23 stops, the air regulator 36 closes the inlet air valve 31 to prevent the system pressure from going up. This is achieved in that the inlet valve is controlled by the reduced system pressure.
According to the invention, the pressure sensor is measuring the reduced air system pressure and thereby indirectly monitoring the flow rate of air through the flushing holes.
According to the present invention, both pressure and compressor speed rotation are considered and therefore the air flow rate is completely controlled.
A consequence of the present invention is that with a given pressure in the air inlet path and varying the compressor speed rotation, the air flow rate will vary linearly with the compressor speed rotation.

Claims

1. An arrangement in a rock drill rig (10) comprising an inlet valve (31) arranged upstream a displacement compressor (32) that is used for supplying an air flow (34) to at least one flushing hole (23) in the surface of a drill bit (20), the drill rig (10) further comprising an regulator (35) arranged to regulate the system pressure in the air flow path (34) downstream the compressor and means for detecting an flow of air through the at least one flushing hole (23) in the surface of the drill bit, characterised in that the detecting means comprises a pressure sensor (37) arranged between the air regulator (36) and the inlet valve (31) and adapted to measure the reduced system pressure.
2. An arrangement according to claim 1, wherein the displacement compressor (32) is a rotary compressor with constant rotation speed.
3. An arrangement according to claim 1, wherein the displacement compressor (32) is a rotary compressor with variable rotation speed.
4. A method of detecting an air flow rate through at least one flushing hole (23) in a front surface of a drilling bit (20) arranged in a rock drill rig (10) comprising an inlet valve (31) arranged upstream a displacement compressor (32) that is used for supplying an air flow (34) to the at least one flushing hole (23) in the drill bit, the drill rig (10) further comprises a regulator (35) arranged to regulate the system pressure in the air flow path (34) downstream the compressor, the method comprising
measuring a reduced system pressure between the regulator (35) and the inlet valve (31), and
determining the air flow rate through the drill bit (20) based on the fact that the measured reduced system pressure is inversely proportional to the air flow rate.
5. A method according to claim 4, comprising setting a desired compressor rotation speed.
6. A method according to claim 4 or 5 comprising comparing the determined air flow rate with a predetermined value, if the determined air flow rate is lower than the predetermined value, reduce the speed of the drill bit (20) or stop drilling, or
if the determined air flow rate is equal or higher than the predetermined value, continue drilling.
EP09746914.2A 2008-05-13 2009-04-29 An arrangement and a method for monitoring an air flow in a drill rig Active EP2310620B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
PCT/US2008/006075 WO2009139743A1 (en) 2008-05-13 2008-05-13 Arrangement in a drill rig and a method for monitoring an air flow
PCT/US2009/002668 WO2009139825A2 (en) 2008-05-13 2009-04-29 An arrangement and a method for monitoring an air flow in a drill rig

Publications (2)

Publication Number Publication Date
EP2310620A2 true EP2310620A2 (en) 2011-04-20
EP2310620B1 EP2310620B1 (en) 2018-08-15

Family

ID=41510581

Family Applications (1)

Application Number Title Priority Date Filing Date
EP09746914.2A Active EP2310620B1 (en) 2008-05-13 2009-04-29 An arrangement and a method for monitoring an air flow in a drill rig

Country Status (3)

Country Link
EP (1) EP2310620B1 (en)
CN (1) CN102027188B (en)
WO (1) WO2009139825A2 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9341177B2 (en) * 2010-04-20 2016-05-17 Sandvik Intellectual Property Ab Air compressor system and method of operation
SE535421C2 (en) 2010-08-26 2012-07-31 Atlas Copco Rock Drills Ab Method and system for determining a change in a flushing medium flow and rock drilling device
SE535897C2 (en) * 2011-04-20 2013-02-12 Atlas Copco Ind Tech Ab Speed control device for controlling the idle speed of a pneumatic tool
CN102889073A (en) * 2012-09-28 2013-01-23 曾庆义 Device and method for monitoring drilling working state of drilling machine
CN103510847B (en) * 2013-09-10 2016-03-30 安徽三山机械制造有限公司 A kind of rotary drill of controlled Compressed Gas injection rate

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3229487C2 (en) * 1982-08-07 1984-10-25 Rudolf Hausherr & Söhne GmbH & Co KG, 4322 Sprockhövel Method for preventing and removing blockages in the scavenging air channels of drill pipes
SE8403686L (en) * 1984-07-12 1986-01-13 Atlas Copco Ab WAY TO CONTROL THE DRILLING OF DEEP TALES AND DRIVE SYSTEM FOR A SINGLE DRILLING MACHINE
FI87830C (en) * 1991-05-23 1993-02-25 Tamrock Oy OVER ANCHORING FOER STARRY AV EN BERGBORRMASKINS LUFTMATNING
FI109143B (en) * 2001-04-04 2002-05-31 Oy Atlas Copco Rotex Ab Drilling method and drilling equipment
FI123636B (en) * 2006-04-21 2013-08-30 Sandvik Mining & Constr Oy A method for controlling the operation of a rock drilling machine and a rock drilling machine
US7503409B2 (en) * 2006-04-25 2009-03-17 Schramm, Inc. Earth drilling rig having electronically controlled air compressor
US7287359B1 (en) 2006-06-08 2007-10-30 Poly-Clip System Corp. Tag lifter plate

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2009139825A2 *

Also Published As

Publication number Publication date
WO2009139825A3 (en) 2010-03-18
WO2009139825A8 (en) 2010-12-09
CN102027188A (en) 2011-04-20
CN102027188B (en) 2015-08-05
EP2310620B1 (en) 2018-08-15
WO2009139825A2 (en) 2009-11-19

Similar Documents

Publication Publication Date Title
KR101056004B1 (en) How to control the operation of the rock drill and rock drill
EP2310620B1 (en) An arrangement and a method for monitoring an air flow in a drill rig
US20150361743A1 (en) Arrangement and method for feeding flushing fluid
CN1301826C (en) Method and device for monitoring impactor operation
US7314349B2 (en) Fluid level control system for progressive cavity pump
CN106837303B (en) Method for determining drilling depth in real time according to operation parameters of hydraulic drilling machine
US8813870B2 (en) Arrangement and a method for monitoring an air flow in a drill rig
SE526462C2 (en) Procedure, program and arrangement for the control of slag drilling
AU2004258133B2 (en) Instrumented drill head, related drilling/bolting machines, and methods
WO2009139743A1 (en) Arrangement in a drill rig and a method for monitoring an air flow
JP5396467B2 (en) Air flow monitoring structure and air flow monitoring method in rock drilling apparatus
AU2011293947B2 (en) Method and system for determining a variation in a flushing medium flow and rock drilling apparatus
BR0017447B1 (en) AUTOMATIC CONTROL PROCESS FOR A RACING HOLE HYDRAULIC OPENER
CN107848086B (en) Dust suction module for a hand-held power tool and method for controlling the same
CN112282732A (en) Method for Determining Coal Seam Gas Occurrence Using Gas While Drilling Parameters
SE534879C2 (en) Method, system and rock drilling device for controlling the rotational speed of a rock drilling tool
RU2029049C1 (en) Method for determination of serviceability of rock cutting tool
BG3658U1 (en) System for monitoring and regulating air flow in a drilling machine

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20101208

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA RS

DAX Request for extension of the european patent (deleted)
GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: GRANT OF PATENT IS INTENDED

INTG Intention to grant announced

Effective date: 20180222

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE PATENT HAS BEEN GRANTED

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: EPIROC ROCK DRILLS AKTIEBOLAG

Owner name: EPIROC DRILLING SOLUTIONS LLC

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

Ref country code: GB

Ref legal event code: FG4D

Ref country code: AT

Ref legal event code: REF

Ref document number: 1029978

Country of ref document: AT

Kind code of ref document: T

Effective date: 20180815

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 602009053876

Country of ref document: DE

REG Reference to a national code

Ref country code: SE

Ref legal event code: TRGR

REG Reference to a national code

Ref country code: NL

Ref legal event code: MP

Effective date: 20180815

REG Reference to a national code

Ref country code: LT

Ref legal event code: MG4D

REG Reference to a national code

Ref country code: AT

Ref legal event code: MK05

Ref document number: 1029978

Country of ref document: AT

Kind code of ref document: T

Effective date: 20180815

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20181115

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

Ref country code: AT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20181116

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20181215

Ref country code: NO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20181115

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

Ref country code: ES

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

Ref country code: HR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

Ref country code: PL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 602009053876

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20190516

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 602009053876

Country of ref document: DE

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

REG Reference to a national code

Ref country code: BE

Ref legal event code: MM

Effective date: 20190430

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20190429

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20190429

Ref country code: MC

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20190430

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20190430

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20190429

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20191101

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20190430

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: TR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20190429

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20190430

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20181215

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO

Effective date: 20090429

Ref country code: MT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180815

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 20260319

Year of fee payment: 18

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FI

Payment date: 20260319

Year of fee payment: 18