Single body large-diameter pneumatic down-the-hole hammer

Abstract

The invention relates to a single body large-diameter pneumatic down-the-hole hammer. The single body large-diameter pneumatic down-the-hole hammer comprises a drill, a spline shaft, a spline sleeve, a cylinder body, a gas distribution sleeve, a bush, an upper flange, an intermediate flange, a piston and a central gas pipe which are coaxially connected with one another, wherein the central gas pipe is arranged in an inner hole of the piston and is a double-core pipe; a gas-guide annular groove is formed between an outer core pipe and an inner core pipe of the double-core pipe; an ejecting hole communicated with the inner core pipe is formed on the spline shaft connected with the drill; an exhaust check valve is arranged at an inlet of the ejecting hole; the intermediate flange is providedwith an exhaust channel and an intake channel; and an exhaust throttle valve is arranged in the exhaust channel. The single body large-diameter pneumatic down-the-hole hammer of the invention can achieve good gas lifting reverse circulation slag-absorbing and slag-discharging effects, effectively preventing the abrasion of parts caused by internal movement due to slurry recharge, is compact and reasonable in structure, light in weight and low in manufacturing cost, is convenient to assemble and maintain, and has high working efficiency.

Description

technical field [0001] The invention relates to a large-diameter pneumatic down-the-hole hammer with a single double-core tube. The down-the-hole hammer is used as a rotary drilling tool for the construction of large-diameter bored piles, and is suitable for various types of rotary drilling rigs to drill in complex and hard formations. Hole work. Background technique [0002] The construction of bored piles by rotary drilling rigs is an efficient and high-quality hole-forming technology commonly used in the construction industry at present, but the conventional drilling tools used by rotary drilling rigs encounter great difficulties in the construction of hard ground. Modern high-rise buildings, high-speed rail and highway bridge foundations all require bored piles to be embedded in the bedrock to improve the bearing capacity and disaster resistance, so as to achieve a longer service life. In addition, drilling operations in coastal areas and mountainous areas are often used...

AI Technical Summary

Problems solved by technology

In order to make the rotary drilling rig have the ability to work in hard formations, various measures have been implemented, such as the use of rock barrel drills, pick-inserted drill buckets, and combined roller cone bits. The construction ability of hard formations, but its disadvantages are low efficiency, fast tool wear, and the footage is very slow in micro-weathered rock formations with a compressive strength exceeding 120MPa, and it is even impossible to drill.

[0003] Patent CN2066480U once provided a kind of wet closed type reverse circulation pneumatic down-the-hole hammer, which adopts the technology of impact rotation combined with reverse circulation slag discharge for hard rock drilling, and can obtain higher efficiency in hard rock areas, but its shortcomings Yes: The exhaust channel with double-layer outer cylinder liner structure makes the structure bulky, difficult to process and high in cost; only adopts pump suction reverse circulation method to discharge slag, which has strict requirements on the sealing effect of drilling tools and is easy to block; mud is easy to pass through Cracks entering the cylinder lead to rapid wear of the piston, the structure of the drill bit is not optimized, and the flow field at the bottom of the hole is not conducive to slag absorption

[0004] The forward circulation or reverse circulation combined down-the-hole hammer proposed by the patents KR2005011865A and KR20060096240A adopts a local circulation mode, and a slag collection tube is provided on the drilling tool. During operation, rock slag debris needs to be collected in the slag collection tube, and then lifted to the Surface slag unloading, low drilling efficiency, and frequent tripping and tripping may easily lead to damage to the gas distribution hose; in addition, due to the large air consumption of the combined hammer, the working status of each hammer is not easy to balance, which affects the overall rock-breaking effect of impact; The slag collecting barrel and the overall height of the drilling tool are greatly increased, which makes it inconvenient to disassemble and assemble on the rotary drilling rig

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