Pressurized fluid flow system for dth hammers and positive circulation hammers based on said pressurized flow system

Abstract

A pressurized fluid flow system for a positive circulation down-the-hole hammer comprising a cylinder coaxially disposed between a housing and a piston having inside a front chamber and a rear chamber at opposite sides of the piston The contained pressurized fluid is reciprocated by changes in pressure, the supply of fluid to / from these chambers is directed through sets of supply and discharge channels defined by grooves on the outer surface of the cylinder and arranged in parallel. The discharge of the chambers, the flow of fluid into and out of the front and rear chambers is controlled only by the relative overlap of the piston and cylinder and directing the flow of fluid below the inner surface of the cylinder and above the outer surface of the piston. A hammer provided with this system includes a drill head with one or more flushing passages.

Description

technical field [0001] The present invention generally relates to a pressurized fluid flow system for impact mechanisms operated using pressurized fluid, particularly for DTH (Down-The-Hole: down-the-hole) hammers, and more particularly for positive cycle DTH hammers, And the invention relates to a DTH hammer with said system. Background technique [0002] DTH Hammer [0003] There are various percussion drilling mechanisms that use pressurized fluid as the device for transmitting power. These percussion drilling mechanisms include DTH hammers which are widely used in the drilling industry, mining industry and civil engineering and construction of water, oil and geothermal wells. A cylindrical DTH hammer is used by assembling it on a drilling rig at the surface of the earth. The drilling rig also includes a drill string comprising rods assembled together, understood as the rear end further distal from the hammer bit (elements described in the specification below) assemble...

AI Technical Summary

Problems solved by technology

[0067] The disadvantages of this flow system are the same as those associated with Type A and Type D flow systems, in particular negatively impacting the design of the bit in two respects

The first aspect is that multiple manufacturing processes are required to create channels in the outer surface of the bit, which increases the manufacturing cost of the hammer

A second aspect is that, due to the presence of these channels, the drag surface of the keyways (which depends on the contact area of ​​each keyway individually and the total number of keyways) may not be sufficient in some applications

[0074] The disadvantages in this example (patent US4819746) are the same as those of the Type A flow system, and the design of the bit is also negatively affected in the same two aspects already mentioned for the Type 1 flow system plus a third

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