Abstract: A return exhaust assembly 50 for a reverse circulation hammer H comprises return tube 52 having first and second ends and a seat 56 at or near the first end 54. An exhaust sleeve 58 has: a section 60 seated and resiliently supported on the seat 56; and, a portion 62 that extends to and includes an end 64 of the exhaust sleeve 58 distal the section 60. The portion 60 surrounds a length of the return tube 52 with an annular clearance 66 formed between the return tube 52 and the sleeve 58 from a down hole end of the seat 56 to the distal end 64 of the exhaust sleeve 58. This arrangement allows relative movement, and therefore a degree of misalignment between the exhaust sleeve 58 and the return tube.

Abstract: A return exhaust assembly (50) for a reverse circulation hammer H comprises return tube (52) having first and second ends and a seat (56) at or near the first end (54). An exhaust sleeve (58) has: a section (60) seated and resiliently supported on the seat (56); and, a portion (62) that extends to and includes an end (64) of the exhaust sleeve (58) distal the section (60). The portion (60) surrounds a length of the return tube (52) with an annular clearance 66 formed between the return tube (52) and the sleeve (58) from a down hole end of the seat (56) to the distal end (64) of the exhaust sleeve (58). This arrangement allows relative movement, and therefore a degree of misalignment between the exhaust sleeve (58) and the return tube.

Abstract: A return exhaust assembly (50) for a reverse circulation hammer H comprises return tube (52) having first and second ends and a seat (56) at or near the first end (54). An exhaust sleeve (58) has: a section (60) seated and resiliently supported on the seat (56); and, a portion (62) that extends to and includes an end (64) of the exhaust sleeve (58) distal the section (60). The portion (60) surrounds a length of the return tube (52) with an annular clearance 66 formed between the return tube (52) and the sleeve (58) from a down hole end of the seat (56) to the distal end (64) of the exhaust sleeve (58). This arrangement allows relative movement, and therefore a degree of misalignment between the exhaust sleeve (58) and the return tube.

Abstract: A down the hole hammer (10) incorporates: an inner tube assembly (100); a fluid flow control system (200); a bit retaining system (400); a porting sleeve (600); and a piston (700). Each of the: inner tube assembly (100); fluid flow control system (200); bit retaining system (400); porting sleeve (600); and piston (700) in their own right provide benefit to the overall operation and/or reliability of the hammer (10).