A down-the-hole drilling apparatus

Abstract

NOT VISIBLE DUE TO STATUS OF PATENT

Description

[0001] A DOWN-THE-HOLE DRILLING APPARATUS

[0002] Technical Field

[0003] The disclosure relates to a down-the-hole drilling apparatus. Further, the disclosure relates to a drilling rig comprising such a down-the-hole drilling apparatus.

[0004] Background

[0005] For breaking or fracturing rock and excavating and drilling tunnels or rooms under ground, or above ground, drilling rigs having a down-the-hole drilling apparatus for drilling into to a rock formation, or rock, may be used. Some drilling rigs may be provided with means for propulsion of the drilling rig, such as wheels or continuous tracks, while some drilling rigs may be without means for propulsion.

[0006] Summary

[0007] The inventors have found drawbacks in conventional solutions for down-the-hole drilling. For example, some conventional solutions are not efficient or robust enough and can be further improved.

[0008] An object of embodiments of the disclosure is to provide a solution which mitigates or solves drawbacks and problems of conventional solutions.

[0009] The above and further objects are solved by the subject matter of the appended independent claims. Further advantageous embodiments can be found in the dependent claims.

[0010] According to a first aspect of the disclosure, the above mentioned and other objects are achieved with a down-the-hole drilling apparatus, wherein the down-the-hole drilling apparatus has a top end and a bottom end, wherein the down-the-hole drilling apparatus comprises a coupler for coupling the down-the-hole drilling apparatus to a drill string, the coupler being positioned at the top end, wherein the down-the-hole drilling apparatus is configured to hold a drill bit to be positioned at the bottom end, wherein the down-the-hole drilling apparatus comprises a fluid-operated piston for directly or indirectly striking the drill bit, wherein the piston is movable in relation to the coupler, wherein the down-the-hole drilling apparatus comprises a bottom working chamber, wherein the down-the-hole drilling apparatus comprises a top working chamber positioned between the bottom working chamber and the coupler, wherein the top and bottom working chambers are configured to be alternately evacuated and fed with fluid for the fluid-operation of the piston, wherein the down-the-hole drilling apparatus comprises a fluid feed system for one or more inflow fluid streams to one or more of the top and bottom working chambers, wherein the down-the-hole drilling apparatus comprises a fluid exhaust system for one or more exhaust fluid streams from one or more of the top and bottom working chambers, the fluid exhaust system being positioned at the top end, wherein the down-the-hole drilling apparatus comprises a check valve configured both as a fluid inlet valve of the fluid feed system and as a fluid exhaust valve of the fluid exhaust system, wherein the check valve is movable in relation to the coupler, wherein the fluid exhaust system comprises one or more exhaust ports which opens / open to the ambient outside the down-the-hole drilling apparatus, and wherein the fluid exhaust system comprises one or more first passages for guiding the one or more exhaust fluid streams outside the check valve from one or more of the top and bottom working chambers to the one or more exhaust ports.

[0011] An advantage of the down-the-hole drilling apparatus according to the first aspect is an improved rock drilling in relation to conventional solutions. For example, an advantage of the down-the-hole drilling apparatus according to the first aspect is a significant reduction in wear on the down-the-hole drilling apparatus, such as on the drill bit, which results in an extended product lifetime and extended service intervals. An advantage of the down-the-hole drilling apparatus according to the first aspect is a more efficient rock drilling in relation to conventional solutions. An advantage of the down-the-hole drilling apparatus according to the first aspect is an improved control of the rock drilling. An advantage of the down-the-hole drilling apparatus according to the first aspect is an improved fluid-control of the piston. An advantage of the down-the- hole drilling apparatus according to the first aspect is an improved control of the fluid flow from one or more of the top and bottom working chambers. An advantage of the down-the-hole drilling apparatus according to the first aspect is an enhanced robustness and durability of the down-the-hole drilling apparatus in relation to conventional solutions.

[0012] Conventionally, exhaust or outflow fluid streams may be guided from one or more of the top and bottom working chambers to the ambient via one or more outlet ports positioned at the bottom end of the down-the-hole drilling apparatus, for example adjacent to, or at, the drill bit. If too much fluid, or fluid at a too high rate, is fed to the down-the-hole drilling apparatus, not all fluid can be let out via the bottom end, or via the drill bit, in a suitable manner. Thus, a conventional solution is to let out at least some of the fluid via a fluid exhaust system located at the top end of the down-the-hole drilling apparatus. The inventors have found that by guiding the one or more exhaust fluid streams outside the check valve from one or more of the top and bottom working chambers to one or more exhaust ports of the fluid exhaust system, the check valve and / or the fluid exhaust system may be designed in a more robust manner, and thus improving or enhancing the robustness and the durability of the down-the-hole drilling apparatus. For example, for some embodiments, since the one or more exhaust fluid streams is / are guided outside the check valve, the check valve may be solid instead of being hollow. By the innovative guidance of the one or more exhaust fluid streams and outlet via the one or more exhaust ports, the one or more exhaust fluid streams exiting the one or more exhaust ports will provide a fluid flow around or along the exterior of the top end of the down-the-hole drilling apparatus, which will protect the top end of the down-the-hole drilling apparatus from the external abrasive flow of cuttings from the drilling, which subjects the exterior of the down-the-hole drilling apparatus to wear. An advantage of the down-the-hole drilling apparatus according to the first aspect, more specifically of the innovative fluid exhaust system, is that the speed of the fluid through the down-the-hole drilling apparatus and along, or around, the exterior of the down-the-hole drilling apparatus can be reduced, and said reduction of the speed of the fluid reduces the wear on the down-the-hole drilling apparatus, for example the external and / or internal wear on the down-the-hole drilling apparatus. An advantage of the down-the-hole drilling apparatus according to the first aspect is an enhanced durability of parts of the down-the-hole drilling apparatus and an enhanced durability of the drill bit and of the drill string in relation to conventional solutions without negatively impacting the performance or functionality of the down-the-hole drilling apparatus when drilling.

[0013] For some embodiments, the fluid may comprise or consist of one or more of the group of:

[0014] • a gas, such as pneumatic gas;

[0015] • a gas mixture;

[0016] • air;

[0017] • lubricant or lubricating oil;

[0018] • liquid;

[0019] • water;

[0020] • mud;

[0021] • foam;

[0022] • slam;

[0023] • sludge; and

[0024] • oil.

[0025] For some embodiments, the down-the-hole drilling apparatus may comprise the drill bit positioned at the bottom end of the down-the-hole drilling apparatus. For some embodiments, it may be defined that the piston is also movable in relation to drill bit.

[0026] According to an advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the fluid feed system comprises one or more second passages for guiding the one or more inflow fluid streams outside the check valve to one or more of the top and bottom working chambers. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0027] According to a further advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the check valve is without any internal passage for guiding the one or more exhaust fluid streams from one or more of the top and bottom working chambers to the one or more exhaust ports. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling. An advantage of this embodiment is a further enhanced robustness and durability of the check valve and / or of the fluid exhaust system, and thus a further enhanced robustness and durability of the down-the-hole drilling apparatus.

[0028] According to another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the check valve is without any internal passage for guiding the one or more inflow fluid streams to one or more of the top and bottom working chambers. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling. An advantage of this embodiment is a further enhanced robustness and durability of the check valve and / or of the fluid exhaust system, and thus a further enhanced robustness and durability of the down- the-hole drilling apparatus.

[0029] According to yet another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the check valve is without any internal passage for guiding a fluid stream. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling. An advantage of this embodiment is a further enhanced robustness and durability of the check valve and / or of the fluid exhaust system, and thus a further enhanced robustness and durability of the down-the-hole drilling apparatus.

[0030] According to still another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the check valve comprises a valve body movable in relation to the coupler, wherein the valve body is solid. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling. By “solid” is meant being without an internal cavity. An advantage of this embodiment is a further enhanced robustness and durability of the check valve and / or of the fluid exhaust system, and thus a further enhanced robustness and durability of the down-the-hole drilling apparatus.

[0031] According to an advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the check valve is solid. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling. An advantage of this embodiment is a further enhanced robustness and durability of the check valve and / or of the fluid exhaust system, and thus a further enhanced robustness and durability of the down-the-hole drilling apparatus.

[0032] According to a further advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the down-the-hole drilling apparatus comprises a compartment holding the check valve. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0033] According to another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the compartment has a top section and a bottom section, wherein the bottom section of the compartment forms a section of the one or more first passages. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0034] According to yet another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the top section of the compartment forms a section of the one or more second passages. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0035] According to still another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the compartment and the top and bottom sections of the compartment are at least partly defined by one or more inner surfaces, wherein the check valve comprises a top end portion and a bottom end portion, and wherein one or more surface regions of the bottom end portion of the check valve and one or more of the one or more inner surfaces of the bottom section of the compartment form a section of the one or more first passages.

[0036] An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0037] According to an advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, one or more surface regions of the top end portion of the check valve and one or more of the one or more inner surfaces of the top section of the compartment form a section of the one or more second passages. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0038] According to a further advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the coupler comprises, or forms, the one or more exhaust ports. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling. An advantage of this embodiment is a further enhanced robustness and / or durability of the down-the-hole drilling apparatus.

[0039] According to another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the fluid exhaust system comprises two or more exhaust ports which open to the ambient. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling. An advantage of this embodiment is a further enhanced robustness and / or durability of the down-the-hole drilling apparatus.

[0040] According to yet another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the down-the-hole drilling apparatus has a longitudinal extension extending from the top end to the bottom end, wherein the longitudinal extension of the down-the-hole drilling apparatus extends in an axial direction, and wherein the two or more exhaust ports are distributed around the circumference of the down-the-hole drilling apparatus.

[0041] An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling. An advantage of this embodiment is a further enhanced robustness and / or durability of the down-the-hole drilling apparatus.

[0042] According to still another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the down-the-hole drilling apparatus has a longitudinal extension extending from the top end to the bottom end, wherein the longitudinal extension of the down-the-hole drilling apparatus extends in an axial direction, and wherein the one or more exhaust ports comprises / comprise a gap extending around the circumference of the down-the-hole drilling apparatus.

[0043] An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling. An advantage of this embodiment is a further enhanced robustness and / or durability of the down-the-hole drilling apparatus.

[0044] According to an advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the down-the-hole drilling apparatus comprises a tubular casing which houses the piston and at least partly houses the coupler, the fluid feed system, the fluid exhaust system and the check valve.

[0045] According to a further advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the coupler and the tubular casing form the one or more exhaust ports. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling. An advantage of this embodiment is a further enhanced robustness and / or durability of the down-the-hole drilling apparatus.

[0046] According to another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the tubular casing has one or more inner surfaces, wherein the coupler and one or more of the one or more inner surfaces of the tubular casing form a section of the one or more first passages. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling. An advantage of this embodiment is a further enhanced robustness and / or durability of the down-the-hole drilling apparatus.

[0047] According to yet another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the coupler is directly attached to the tubular casing. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0048] According to still another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the check valve is spring-loaded. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0049] According to an advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the check valve comprises one or more first sealings for the closure of the one or more first passages. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0050] According to a further advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the one or more first sealings comprises / comprise a first annular sealing member extending around the circumference of the check valve. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0051] According to another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the check valve comprises one or more second sealings for the closure of the one or more second passages. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0052] According to yet another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the one or more second sealings comprises / comprise a second annular sealing member extending around the circumference of the check valve. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0053] According to still another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the check valve is configured to simultaneously open the one or more first passages and the one or more second passages when one or more inflow fluid streams acts on the check valve. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0054] According to an advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the check valve is configured to simultaneously close the one or more first passages and the one or more second passages. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0055] According to a further advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the check valve is configured to close and open the one or more first passages. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0056] According to another advantageous embodiment of the down-the-hole drilling apparatus according to the first aspect, the check valve is configured to close and open the one or more second passages. An advantage of this embodiment is a further improved rock drilling and / or a further improved control of the rock drilling.

[0057] According to a second aspect of the disclosure, the above mentioned and other objects are achieved with a drilling rig comprising a down-the-hole drilling apparatus according to any one of the embodiments mentioned above or below, and one or more compressors for controlling the one or more inflow fluid streams.

[0058] Advantages of the drilling rig according to the second aspect correspond to advantages of the down-the-hole drilling apparatus according to the first aspect and its embodiments mentioned above or below. For some embodiments, instead of one or more compressors, the drilling rig may comprise one or more pumps.

[0059] According to a third aspect of the disclosure, the above mentioned and other objects are achieved with a method for rock drilling, wherein the method comprises: drilling by usage of a down-the-hole drilling apparatus; wherein the down-the-hole drilling apparatus has a top end and a bottom end, wherein the down-the-hole drilling apparatus comprises a coupler for coupling the down-the-hole drilling apparatus to a drill string, the coupler being positioned at the top end, wherein the down-the-hole drilling apparatus is configured to hold a drill bit to be positioned at the bottom end, wherein the down-the-hole drilling apparatus comprises a fluid-operated piston for directly or indirectly striking the drill bit, wherein the piston is movable in relation to the coupler, wherein the down-the-hole drilling apparatus comprises a bottom working chamber, wherein the down-the-hole drilling apparatus comprises a top working chamber positioned between the bottom working chamber and the coupler, wherein the down-the-hole drilling apparatus comprises a fluid feed system for one or more inflow fluid streams to one or more of the top and bottom working chambers, wherein the down-the-hole drilling apparatus comprises a fluid exhaust system for one or more exhaust fluid streams from one or more of the top and bottom working chambers, the fluid exhaust system being positioned at the top end, wherein the down-the-hole drilling apparatus comprises a check valve configured both as a fluid inlet valve of the fluid feed system and as a fluid exhaust valve of the fluid exhaust system, wherein the check valve is movable in relation to the coupler, wherein the fluid exhaust system comprises one or more exhaust ports opening to the ambient outside the down-the-hole drilling apparatus, and wherein the fluid exhaust system comprises one or more first passages, wherein the method further comprises: alternately evacuating and feeding fluid from / to the top and bottom working chambers for the fluid-operation of the piston; and guiding, by usage of the one or more first passages of the fluid exhaust system, the one or more exhaust fluid streams outside the check valve from one or more of the top and bottom working chambers to the one or more exhaust ports.

[0060] Advantages of the method according to the third aspect correspond to advantages of the down-the-hole drilling apparatus according to the first aspect and its embodiments mentioned above or below.

[0061] According to an advantageous embodiment of the method according to the third aspect, the method comprises: guiding, by usage of one or more second passages of the fluid feed system, the one or more inflow fluid streams outside the check valve to one or more of the top and bottom working chambers.

[0062] The above-mentioned features and embodiments of the down-the-hole drilling apparatus may be combined in various possible ways providing further advantageous embodiments.

[0063] Further advantageous embodiments of the down-the-hole drilling apparatus, the drilling rig and the method and further advantages with the embodiments emerge from the detailed description of embodiments.

[0064] Brief Description of the Drawings

[0065] Embodiments of the disclosure will now be illustrated, for exemplary purposes, in more detail by way of embodiments and with reference to the enclosed drawings, where similar references are used for similar parts, in which:

[0066] Figure 1 is a schematic side view of a first embodiment of the drilling rig according to the second aspect of the disclosure, which may include and / or use embodiments of the down-the-hole drilling apparatus according to the first aspect of the disclosure;

[0067] Figure 2 is a schematic side view of a second embodiment of the drilling rig according to the second aspect of the disclosure, which may include and / or use embodiments of the down-the-hole drilling apparatus according to the first aspect of the disclosure;

[0068] Figure 3A is a schematic side view of a first embodiment of the down-the-hole drilling apparatus according to the first aspect of the disclosure

[0069] Figure 3B is a schematic combined sectional view of the down-the-hole drilling apparatus of figure 3A with the check valve in a closed position, wherein the side to the left of the axis A shows a section illustrating the first passages while the side to the right of the axis A shows another section illustrating the second passages;

[0070] Figure 4 is a schematic combined sectional view of the down-the-hole drilling apparatus of figure 3A with the check valve in an open position, wherein the side to the left of the axis A shows a section illustrating the first passages while the side to the right of the axis A shows another section illustrating the second passages;

[0071] Figure 5 is a schematic combined sectional view of the down-the-hole drilling apparatus of figure 3A with the check valve in an open position, wherein the side to the left of the axis A shows a section illustrating the first passages while the side to the right of the axis A shows another section illustrating the second passages during the evacuation of the bottom working chamber;

[0072] Figure 6 is a schematic combined sectional view of the down-the-hole drilling apparatus of figure 3A with the check valve in an open position, wherein the side to the left of the axis A shows a section illustrating the first passages while the side to the right of the axis A shows another section illustrating the second passages during the evacuation of the top working chamber;

[0073] Figure 7 is a schematic sectional view of the top part of the down-the-hole drilling apparatus of figure 3A with the check valve in a closed position, wherein the section illustrates the second passages;

[0074] Figure 8 is a schematic sectional view of the top part of the down-the-hole drilling apparatus of figure 3A with the check valve in a closed position, wherein the section illustrates the first passages;

[0075] Figure 9 is a schematic sectional view of the top part of the down-the-hole drilling apparatus of figure 3A with the check valve in an open position, wherein the section illustrates the second passages;

[0076] Figure 10 is a schematic sectional view of the top part of the down-the-hole drilling apparatus of figure 3A with the check valve in an open position, wherein the section illustrates the first passages;

[0077] Figure 11 is a schematic combined sectional view of a second embodiment of the down-the-hole drilling apparatus according to the first aspect of the disclosure with the check valve in a closed position, wherein the side to the left of the axis B shows a section illustrating the first passages while the side to the right of the axis B shows another section illustrating the second passages; Figure 12A is a schematic combined sectional view of the down-the-hole drilling apparatus of figure 11 with the check valve in an open position, wherein the side to the left of the axis B shows a section illustrating the first passages while the side to the right of the axis B shows another section illustrating the second passages;

[0078] Figure 12B is an enlargement of the top part of the down-the-hole drilling apparatus of figure 12A;

[0079] Figure 13 is a schematic perspective view of an embodiment of the coupler of the down-the-hole drilling apparatus of figures 11 and 12A-B;

[0080] Figure 14 is a schematic flow chart illustrating aspects of embodiments of the method according to the third aspect of the disclosure; and

[0081] Figure 15 is another schematic flow chart illustrating further aspects of embodiments of the method according to the third aspect of the disclosure.

[0082] Detailed Description

[0083] With reference to figures 1 and 2, aspects of embodiments of a drilling rig 200a; 200b are schematically illustrated. With reference to figures 3 to 13, aspects of embodiments of a down-the-hole drilling apparatus 100a; 100b are schematically illustrated.

[0084] With reference to figure 1 , a first embodiment of the drilling rig 200a is schematically illustrated. The drilling rig 200a may have equipment 206, or means, for propulsion. In the embodiment of figure 1 , the equipment 206 for propulsion comprises one or more continuous tracks 208. However, instead of continuous tracks 208, the equipment 206 for propulsion may comprise wheels, or any other means for propulsion. The drilling rig 200a may include a feed beam 210 and a rotation unit 212 connected to the feed beam 210. The rotation unit 212 may hold a drill string 202. The drilling rig 200a includes a down-the-hole drilling apparatus 100a; 100b according to any one of the embodiments disclosed below or above, for drilling a drill hole 214. The drilling rig 200a includes one or more compressors 216 for controlling one or more inflow fluid streams 118 disclosed in further detailed hereinbelow. For some embodiments, the drilling rig 200a may comprise one or more electric battery units for driving and / or operating the drilling rig 200a and / or may comprise one or more combustion engines for the same purpose. For example, the drilling rig 200a may be utilised in surface mining, underground mining and raise boring. The drilling rig 200a may include a cabin 222, from where the drilling process may be controlled by an operator. Alternatively, the drilling rig 200b may be remotely controlled or be configured to operate autonomously. It is to be understood that the drilling rig 200b may comprise additional tools and equipment.

[0085] With reference to figure 2, a second embodiment of a drilling rig 200b is schematically illustrated. The drilling rig 200b of figure 2 may be referred to as a platform drilling rig. The drilling rig 200b of figure 2 may be configured to be placed above and on ground 224. The drilling rig 200b may include a guide 218, or tower, for holding and guiding a drill string 202. The drilling rig 200b may include a rotation unit 212 connected to the guide 218. The rotation unit 212 may hold the drill string 202. The drilling rig 200b includes a down-the-hole drilling apparatus 100a; 100b according to any one of the embodiments disclosed below or above, for drilling a drill hole 214 in a rock formation 220. The drilling rig 200a includes one or more compressors 216 for controlling one or more inflow fluid streams 118 disclosed in further detailed hereinbelow. The drilling rig 200b may include a cabin 222, from where the drilling process may be controlled by an operator. Alternatively, the drilling rig 200b may be remotely controlled or be configured to operate autonomously. The drilling rig 200b may include a carrier 226 to which the guide 218 and cabin 222 and is attached. It is to be understood that the drilling rig 200b may comprise additional tools and equipment. For some embodiments, the drilling rig 200b of figure 2 may be movable by way of a suitable vehicle.

[0086] With reference to figures 3A to 10, aspects of a first embodiment of the down-the-hole drilling apparatus 100a are schematically illustrated. For some embodiments, the down-the-hole drilling apparatus 100a may be referred to as a down-the-hole drilling assembly. The down-the-hole drilling apparatus 100a has a top end 102 and a bottom end 104. The down-the-hole drilling apparatus 100a includes a coupler 106 for coupling the down-the-hole drilling apparatus 100a to a drill string 202 (see figures 1 and 2). The coupler 106 is positioned at the top end 102. For some embodiments, the coupler 106 may be referred to as a back-head. The down-the-hole drilling apparatus 100a is configured to hold a drill bit 108. The drill bit 108 is to be positioned at the bottom end 104. Thus, the down-the-hole drilling apparatus 100a is configured to hold the drill bit 108 at the bottom end 104. With reference to figures 3B to 10, the down-the-hole drilling apparatus 100a includes a fluid-operated (or fluid-actuated) piston 110 for directly or indirectly striking (or impacting) the drill bit 108. For some embodiments, there may be one or more intermediate elements positioned between the piston 110 and the drill bit 108, and the piston 110 may be configured to strike the intermediate element and thus indirectly strike the drill bit 108. The piston 110 is movable in relation to the coupler 106. When the drilling apparatus 100a holds the drill bit 108, it may also be defined that the piston 110 is movable in relation to the drill bit 108.

[0087] With reference to figure 6, the down-the-hole drilling apparatus 100a includes, or forms, a bottom working chamber 112, which is indicated by solid black in figure 6. With reference to figure 5, the down-the-hole drilling apparatus 100a includes, or forms, a top working chamber 114 positioned between the bottom working chamber 112 and the coupler 106. The top working chamber 114 is indicated by solid black in figure 5. The top and bottom working chambers 114, 112 are configured to be alternately evacuated and fed with fluid for the fluid-operation of the piston 110.

[0088] With reference to figures 3B to 10, the down-the-hole drilling apparatus 100a includes a fluid feed system 116 for one or more inflow fluid streams 118 to one or more of the top and bottom working chambers 114, 112. The down-the-hole drilling apparatus 100a includes a fluid exhaust system 120 for one or more exhaust fluid streams 122 from one or more of the top and bottom working chambers 114, 112. The fluid exhaust system 120 is positioned at the top end 102.

[0089] With reference to figures 3B to 10, the down-the-hole drilling apparatus 100a includes a check valve 124a configured (or, designed, structured, or formed) both as a fluid inlet valve of the fluid feed system 116 and as a fluid exhaust valve (or fluid outlet valve) of the fluid exhaust system 120. The check valve 124a is movable in relation to the coupler 106. For some embodiments, the check valve 124a may be referred to as a non-return valve, or a one-way valve, i.e. , a valve that normally, or in general, allows fluid to flow in only one direction. The fluid exhaust system 120 includes one or more exhaust ports 126a opening to the ambient 204, i.e., to the surroundings, outside the down-the-hole drilling apparatus 100a. The fluid exhaust system 120 includes one or more first passages 128a for guiding the one or more exhaust fluid streams 122 outside the check valve 124a from one or more of the top and bottom working chambers 114 to the one or more exhaust ports 126a. The fact that the one or more exhaust fluid streams 122 is / are guided outside the check valve 124a implies that the one or more exhaust fluid streams 122 is / are not guided through or inside the check valve 124a. For some embodiments, it may be defined that the check valve 124a is movable between a closed position and an open position. For some embodiments, it may be defined that the one or more exhaust fluid streams 122 from one or more of the top and bottom working chambers 114, 112 to the one or more exhaust ports 126a; 126b is / are guided past the check valve 124a outside thereof, when the check valve 124a is in the open position. For some embodiments, the first passage 128a, which may be referred to as a first path, may comprise one or more conduits.

[0090] With reference to figures 3B to 10, for some embodiments, the fluid feed system 116 may include one or more second passages 130a for guiding the one or more inflow fluid streams 118 outside the check valve 124a to one or more of the top and bottom working chambers 114, 112. The fact that the one or more inflow fluid streams 118 is / are guided outside the check valve 124a implies that the one or more inflow fluid streams 118 is / are not guided through or inside the check valve 124a. For some embodiments, it may be defined that the one or more inflow fluid streams 118 to one or more of the top and bottom working chambers 114, 112 is / are guided past the check valve 124a outside thereof, when the check valve 124a is in the open position. For some embodiments, the second passage 128b, which may be referred to as a second path, may comprise one or more conduits.

[0091] With reference to figures 3B to 10, for some embodiments, it may be defined that the check valve 124a is without any internal passage for guiding the one or more exhaust fluid streams 122 from one or more of the top and bottom working chambers 114, 112 to the one or more exhaust ports 126a. For some embodiments, it may be defined that the check valve 124a is without any internal passage for guiding the one or more inflow fluid streams 118 to one or more of the top and bottom working chambers 114, 112. For some embodiments, it may be defined that the check valve 124a is without any internal passage for guiding a fluid stream. With reference to figures 3B to 10, for some embodiments, it may be defined that the check valve 124a includes a valve body 125a movable in relation to the coupler 106. For some embodiments, the valve body 125a may be solid. For some embodiments, the check valve 124a may be solid. In general, by “solid” is meant that the valve body 125a or check valve 124a is without an internal cavity.

[0092] With reference to figures 7 to 10, for some embodiments, the down-the-hole drilling apparatus 100a may include a compartment 132a holding the check valve 124a. For some embodiments, the compartment 132a may have a top section 134a and a bottom section 136a. The bottom section 136a of the compartment 132a may form a section 138a of the one or more first passages 128a. For some embodiments, the top section 134a of the compartment 132a may form a section of the one or more second passages 130a. For some embodiments, the compartment 132a and the top and bottom sections 134a; 136a of the compartment 132a may be at least partly defined by one or more inner surfaces 140a. The check valve 124a may include a top end portion 142a and a bottom end portion 144a. One or more surface regions 146a of the bottom end portion 144a of the check valve 124a and one or more of the one or more inner surfaces 140a of the bottom section 136a of the compartment 132a may form a section 148a of the one or more first passages 128a. For some embodiments, one or more surface regions 150a of the top end portion 142a of the check valve 124a and one or more of the one or more inner surfaces 140a of the top section 134a of the compartment 132a may form a section 152a of the one or more second passages 130a.

[0093] With reference to figures 7 to 10, for some embodiments, the coupler 106 may include, or form, the one or more exhaust ports 126a. The fluid exhaust system 120 may include two or more exhaust ports 126a which open to the ambient 204. For some embodiments, it may be defined that down-the-hole drilling apparatus 100a has a longitudinal extension 154 extending from the top end 102 to the bottom end 104. The longitudinal extension 154 of the down-the-hole drilling apparatus 100a extends in an axial direction 156, and / or in a longitudinal direction. For some embodiments, the two or more exhaust ports 126a may be distributed around the circumference of the down- the-hole drilling apparatus 100b, for example around a longitudinal center axis of the down-the-hole drilling apparatus 100a. For some embodiments, the two or more exhaust ports 126a may be evenly distributed around the circumference of the down- the-hole drilling apparatus 100b.

[0094] With reference to figures 3A to 10, the down-the-hole drilling apparatus 100a may include a tubular casing 160 which houses the piston 110 and at least partly houses the coupler 106, the fluid feed system 116, the fluid exhaust system 120 and the check valve 124a. For some embodiments, the coupler 106 may be directly attached to the tubular casing 160. For other embodiments, the coupler 106 may be indirectly attached to the tubular casing 160 via one or more intermediate members. For some embodiments, the check valve 124a may be spring-loaded, for example by way of a spring 161 or other biasing member. Thus, the check valve 124a may be a springloaded check valve.

[0095] With reference to figure 8, for some embodiments, the check valve 124a may include one or more first sealings 166a for the closure of the one or more first passages 128a. The one or more first sealings 166a may comprise a first annular sealing member 168a, such as an O-ring, extending around the circumference of the check valve 124a.

[0096] With reference to figure 7, for some embodiments, the check valve 124a may include one or more second sealings 170a for the closure of the one or more second passages 130a. The one or more second sealings 170a may comprise a second annular sealing member 172a, such as an O-ring, extending around the circumference of the check valve 124a. For example, said sealings 166a, 170a and annular sealing members 168a, 172a may be made of a material comprising or consisting of a polymer or a polymer composite. In general, the material of the sealings 166a, 170a and annular sealing members 168a, 172a may be different form the material of the valve body 125a.

[0097] With reference to figures 9 and 10, for some embodiments, it may be defined that the check valve 124a is configured to simultaneously open the one or more first passages 128a and the one or more second passages 130a when one or more inflow fluid streams 118 acts on the check valve 124a. With reference to figures 7 and 8, for some embodiments, it may be defined that the check valve 124a is configured to simultaneously close the one or more first passages 128a and the one or more second passages 130a. With reference to figures 7 to 10, for some embodiments, it may be defined that the check valve 124a is configured to close and open the one or more first passages 128a. For some embodiments, it may be defined that the check valve 124a is configured to close and open the one or more second passages 130a.

[0098] With reference to figures 5 and 6, the evacuation of the top and bottom working chambers 114, 112, respectively, is schematically illustrated. In figure 5, the bottom working chamber 112 is evacuated and the fluid flow from the bottom working chamber 112 is indicated by arrows while the top working chamber 114 not being evacuated is indicated by solid black. In figure 6, the top working chamber 114 is evacuated and the fluid flow from the top working chamber 114 is indicated by arrows while the bottom working chamber 112 not being evacuated is indicated by solid black. Said evacuation of the bottom working chamber 112 and top working chamber 114, respectively, may be performed by one or more conventional compressors 216 controlling the one or more inflow fluid streams 118. As illustrated in figures 5 and 6, for some embodiments, the down-the-hole drilling apparatus 100a may comprises a fluid outlet system 174 for one or more outflow fluid streams 176 from one or more of the top and bottom working chambers 114, 112 to one or more outlet ports 178 opening to the ambient 204. The fluid outlet system 174 may be positioned at the bottom end 104 of the down-the-hole drilling apparatus 100a. The one or more outlet ports 178 may be positioned at the bottom end 104 of the down-the-hole drilling apparatus 100a, for example, in, or adjacent to, the drill bit 108.

[0099] With reference to figures 11 to 13, aspects of a second embodiment of the down-the- hole drilling apparatus 100b are schematically illustrated. Several items or features of the second embodiment of the down-the-hole drilling apparatus 100b of figures 11 and 12A-B correspond to items / features of the first embodiments of the down-the-hole drilling apparatus 100a disclosed above in connection with figures 3A to 10 and are thus not repeated here to avoid repetition. Thus, also the down-the-hole drilling apparatus 100b of figures 11 and 12A-B includes, or may include:

[0100] • a check valve 124b;

[0101] • a valve body 125b;

[0102] • one or more exhaust ports 126b;

[0103] • one or more first passages 128b;

[0104] • one or more second passages 130b; • a compartment 132b;

[0105] • top and bottom sections 134b, 136b of the compartment 132b;

[0106] • a section 138b of the one or more first passages 128b formed by the bottom section 136b of the compartment 132b;

[0107] • one or more inner surfaces 140b of the top and bottom sections 134b, 136b of the compartment 132b;

[0108] • top and bottom end portions 142b, 144b of the check valve 124b;

[0109] • one or more surface regions 146b of the bottom end portion 144b of the check valve 124b;

[0110] • a section 148b of the one or more first passages 128b formed by one or more surface regions 146b of the bottom end portion 144b of the check valve 124b and by one or more of the one or more inner surfaces 140b of the bottom section 136b of the compartment 132b;

[0111] • one or more surface regions 150b of the top end portion 142b of the check valve 124b;

[0112] • a section 152b of the one or more second passages 130b formed by one or more surface regions 150b of the top end portion 142b of the check valve 124b and by one or more of the one or more inner surfaces 140b of the top section 134b of the compartment 132b;

[0113] • one or more first sealings 166b;

[0114] • a first annular sealing member;

[0115] • one or more second sealings 170b; and

[0116] • a second annular sealing member.

[0117] The down-the-hole drilling apparatus 100b of figures 11 and 12A-B differs from the down-the-hole drilling apparatus 100a of figures 3A to 10 in that the check valve 124b of figures 11 and 12A-B has a shape different from the shape of the check valve 124a of figures 3B to 10. Further, the down-the-hole drilling apparatus 100b of figures 11 and 12A-B differs from the down-the-hole drilling apparatus 100a of figures 3A to 10 in that the one or more exhaust ports 126b comprises / comprise a gap 158b extending around the circumference of the down-the-hole drilling apparatus 100b, for example around a longitudinal center axis of the down-the-hole drilling apparatus 100b. Further, the down-the-hole drilling apparatus 100b of figures 11 and 12A-B differs from the down-the-hole drilling apparatus 100a of figures 3A to 10 in that the coupler 106 and the tubular casing 160 form the one or more exhaust ports 126b. For some embodiments, it may be defined that the tubular casing 160 has one or more inner surfaces 162. The down-the-hole drilling apparatus 100b of figures 11 and 12A-B differs from the down-the-hole drilling apparatus 100a of figures 3A to 10 in that the coupler 106 and one or more of the one or more inner surfaces 162 of the tubular casing 160 form a section 164b of the one or more first passages 128b.

[0118] With reference to figure 13, an embodiment of the coupler 106 of the down-the-hole drilling apparatus 100b of figures 11 and 12A-B is schematically illustrated. The coupler 106 may have threads 180, 182 for the coupling or attachment with the tubular casing 160 and with the drill string 202, respectively. The coupler 106 may form grooves 184 extending transversely to the threads 180, which may engage with mating threads of the tubular casing 160. Said grooves 184 together with the one or more inner surfaces 162 of the tubular casing 160 may form said section 164b of the one or more first passages 128b.

[0119] With reference to figures 14 and 15, embodiments of a method 400 for rock drilling are schematically illustrated in flow charts.

[0120] With reference to figures 14, embodiments of the method 400 for rock drilling include the steps of:

[0121] • drilling 401 by usage of a down-the-hole drilling apparatus 100a; 100b; wherein the down-the-hole drilling apparatus 100a; 100b has a top end 102 and a bottom end 104, wherein the down-the-hole drilling apparatus 100a; 100b comprises a coupler 106 for coupling the down-the-hole drilling apparatus 100a; 100b to a drill string 202, the coupler 106 being positioned at the top end 102, wherein the down-the-hole drilling apparatus 100a; 100b is configured to hold a drill bit 108 to be positioned at the bottom end 104, wherein the down-the-hole drilling apparatus 100a; 100b comprises a fluid- operated piston 110 for directly or indirectly striking the drill bit 108, wherein the piston 110 is movable in relation to the coupler 106, wherein the down-the-hole drilling apparatus 100a; 100b comprises a bottom working chamber 112, wherein the down-the-hole drilling apparatus 100a; 100b comprises a top working chamber 114 positioned between the bottom working chamber 112 and the coupler 106, wherein the down-the-hole drilling apparatus 100a; 100b comprises a fluid feed system 116 for one or more inflow fluid streams 118 to one or more of the top and bottom working chambers 114, 112, wherein the down-the-hole drilling apparatus 100a; 100b comprises a fluid exhaust system 120 for one or more exhaust fluid streams 122 from one or more of the top and bottom working chambers 114, 112, the fluid exhaust system 120 being positioned at the top end 102, wherein the down-the-hole drilling apparatus 100a; 100b comprises a check valve 124a; 124b configured both as a fluid inlet valve of the fluid feed system 116 and as a fluid exhaust valve of the fluid exhaust system 120, wherein the check valve 124a; 124b is movable in relation to the coupler, wherein the fluid exhaust system 120 comprises one or more exhaust ports 126a; 126b opening to the ambient 204 outside the down-the-hole drilling apparatus 100a; 100b, and wherein the fluid exhaust system 122 comprises one or more first passages 128a; 128b,

[0122] • alternately evacuating 402a and feeding 402b fluid from / to the top and bottom working chambers 114, 112 for the fluid-operation of the piston 110; and

[0123] • guiding 403, by usage of the one or more first passages 128a; 128b of the fluid exhaust system 120, the one or more exhaust fluid streams 122 outside the check valve 124a; 124b from one or more of the top and bottom working chambers 114, 112 to the one or more exhaust ports 126a; 126b.

[0124] With reference to figure 15, some embodiments of the method 400 may include the steps of:

[0125] • guiding 404, by usage of one or more second passages 130a; 130b of the fluid feed system 116, the one or more inflow fluid streams 118 outside the check valve 124a; 124b to one or more of the top and bottom working chambers 114, 112. The embodiments disclosed above may be applied to rock breakage under ground or above ground. Finally, it should be understood that the invention is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.

Claims

Claims1 . A down-the-hole drilling apparatus (100a; 100b), wherein the down-the-hole drilling apparatus (100a; 100b) has a top end (102) and a bottom end (104), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a coupler (106) for coupling the down-the-hole drilling apparatus (100a; 100b) to a drill string (202), the coupler (106) being positioned at the top end (102), wherein the down-the-hole drilling apparatus (100a; 100b) is configured to hold a drill bit (108) to be positioned at the bottom end (104), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a fluid- operated piston (110) for directly or indirectly striking the drill bit (108), wherein the piston (110) is movable in relation to the coupler (106), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a bottom working chamber (112), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a top working chamber (114) positioned between the bottom working chamber (112) and the coupler (106), wherein the top and bottom working chambers (114, 112) are configured to be alternately evacuated and fed with fluid for the fluid-operation of the piston (110), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a fluid feed system (116) for one or more inflow fluid streams (118) to one or more of the top and bottom working chambers (114, 112), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a fluid exhaust system (120) for one or more exhaust fluid streams (122) from one or more of the top and bottom working chambers (114, 112), the fluid exhaust system (120) being positioned at the top end (102), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a check valve (124a; 124b) configured both as a fluid inlet valve of the fluid feed system (116) and as a fluid exhaust valve of the fluid exhaust system (120), wherein the check valve (124a; 124b) is movable in relation to the coupler (106),wherein the fluid exhaust system (120) comprises one or more exhaust ports (126a; 126b) opening to the ambient (204) outside the down-the-hole drilling apparatus (100a; 100b), and wherein the fluid exhaust system (120) comprises one or more first passages (128a; 128b) for guiding the one or more exhaust fluid streams (122) outside the check valve (124a; 124b) from one or more of the top and bottom working chambers (114, 112) to the one or more exhaust ports (126a; 126b).

2. A down-the-hole drilling apparatus (100a; 100b) according to claim 1 , wherein the check valve (124a; 124b) is without any internal passage for guiding the one or more exhaust fluid streams (122) from one or more of the top and bottom working chambers (114, 112) to the one or more exhaust ports (126a; 126b).

3. A down-the-hole drilling apparatus (100a; 100b) according to claim 1 or 2, wherein the check valve (124a; 124b) is without any internal passage for guiding a fluid stream.

4. A down-the-hole drilling apparatus (100a; 100b) according to any one of the claims 1 to 3, wherein the check valve (124a; 124b) comprises a valve body (125a; 125b) movable in relation to the coupler (106), and wherein the valve body (125a; 125b) is solid.

5. A down-the-hole drilling apparatus (100a; 100b) according to any one of the claims 1 to 4, wherein the check valve (124a; 124b) is solid.

6. A down-the-hole drilling apparatus (100a; 100b) according to any one of the claims 1 to 5, wherein the down-the-hole drilling apparatus (100a; 100b) comprises a compartment (132a; 132b) holding the check valve (124a; 124b).

7. A down-the-hole drilling apparatus (100a; 100b) according to claim 6, wherein the compartment (132a; 132b) has a top section (134a; 134b) and a bottom section (136a; 136b), and wherein the bottom section (136a; 136b) of the compartment (132a; 132b) forms a section (138a; 138b) of the one or more first passages (128a; 128b).

8. A down-the-hole drilling apparatus (100a; 100b) according to claim 7, wherein the compartment (132a; 132b) and the top and bottom sections (134a; 136a; 134b, 136b) of the compartment (132a; 132b) are at least partly defined by one or more inner surfaces (140a; 140b), wherein the check valve (124a; 124b) comprises a top end portion (142a; 142b) and a bottom end portion (144a; 144b), and wherein one or more surface regions (146a; 146b) of the bottom end portion (144a; 144b) of the check valve (124a; 124b) and one or more of the one or more inner surfaces (140a; 140b) of the bottom section (136a; 136b) of the compartment (132a; 132b) form a section (148a; 148b) of the one or more first passages (128a; 128b).

9. A down-the-hole drilling apparatus (100a; 100b) according to any one of the claims 1 to 8, wherein the coupler (106) comprises the one or more exhaust ports (126a; 126b).

10. A down-the-hole drilling apparatus (100a; 100b) according any one of the claims 1 to 9, wherein the fluid exhaust system (120) comprises two or more exhaust ports (126a) which open to the ambient (204).

11. A down-the-hole drilling apparatus (100a; 100b) according to claim 10, wherein the down-the-hole drilling apparatus (100a; 100b) has a longitudinal extension (154) extending from the top end (102) to the bottom end (104), wherein the longitudinal extension (154) of the down-the-hole drilling apparatus (100a; 100b) extends in an axial direction (156), and wherein the two or more exhaust ports (126a) are distributed around the circumference of the down-the-hole drilling apparatus (100a; 100b).

12. A down-the-hole drilling apparatus (100a; 100b) according to any one of the claims 1 to 11 , wherein the down-the-hole drilling apparatus (100a; 100b) has a longitudinal extension (154) extending from the top end (102) to the bottom end (104), wherein the longitudinal extension (154) of the down-the-hole drilling apparatus (100a; 100b) extends in an axial direction (156), andwherein the one or more exhaust ports (126b) com prises / com prise a gap (158b) extending around the circumference of the down-the-hole drilling apparatus (100a; 100b).

13. A down-the-hole drilling apparatus (100a; 100b) according to any one of the claims 1 to 12, wherein the down-the-hole drilling apparatus (100a; 100b) comprises a tubular casing (160) which houses the piston (110) and at least partly houses the coupler (106), the fluid feed system (116), the fluid exhaust system (120) and the check valve (124a; 124b).

14. A down-the-hole drilling apparatus (100a; 100b) according to claim 13, wherein the coupler (106) and the tubular casing (160) form the one or more exhaust ports (126b).

15. A down-the-hole drilling apparatus (100a; 100b) according to claim 13 or 14, wherein the tubular casing (160) has one or more inner surfaces (162), and wherein the coupler (106) and one or more of the one or more inner surfaces (162) of the tubular casing (160) form a section (164b) of the one or more first passages (128b).

16. A drilling rig (200a; 200b) comprising a down-the-hole drilling apparatus (100a; 100b) according to any one of the claims 1 to 15, and one or more compressors for controlling the one or more inflow fluid streams (118).

17. A method (400) for rock drilling, wherein the method (400) comprises: drilling (401 ) by usage of a down-the-hole drilling apparatus (100a; 100b); wherein the down-the-hole drilling apparatus (100a; 100b) has a top end (102) and a bottom end (104), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a coupler (106) for coupling the down-the-hole drilling apparatus (100a; 100b) to a drill string (202), the coupler (106) being positioned at the top end (102),wherein the down-the-hole drilling apparatus (100a; 100b) is configured to hold a drill bit (108) to be positioned at the bottom end (104), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a fluid- operated piston (110) for directly or indirectly striking the drill bit (108), wherein the piston (110) is movable in relation to the coupler (106), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a bottom working chamber (112), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a top working chamber (114) positioned between the bottom working chamber (112) and the coupler (106), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a fluid feed system (116) for one or more inflow fluid streams (118) to one or more of the top and bottom working chambers (114, 112), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a fluid exhaust system (120) for one or more exhaust fluid streams (122) from one or more of the top and bottom working chambers (114, 112), the fluid exhaust system (120) being positioned at the top end (102), wherein the down-the-hole drilling apparatus (100a; 100b) comprises a check valve (124a; 124b) configured both as a fluid inlet valve of the fluid feed system (116) and as a fluid exhaust valve of the fluid exhaust system (120), wherein the check valve (124a; 124b) is movable in relation to the coupler (106), wherein the fluid exhaust system (120) comprises one or more exhaust ports (126a; 126b) opening to the ambient (204) outside the down-the-hole drilling apparatus (100a; 100b), and wherein the fluid exhaust system (122) comprises one or more first passages (128a; 128b), wherein the method (400) further comprises: alternately evacuating (402a) and feeding (402b) fluid from / to the top and bottom working chambers (114, 112) for the fluid-operation of the piston (110); and guiding (403), by usage of the one or more first passages (128a; 128b) of the fluid exhaust system (120), the one or more exhaust fluid streams (122) outside the check valve (124a; 124b) from one or more of the top and bottom working chambers (114, 112) to the one or more exhaust ports (126a; 126b).