GQ series hollow-through DTH hammer impactor has the features of simple structure, good performance, reliable working, convenient repair and low air consumption. It can realize multiple functions such as bit core drilling, wireline core drilling and reverse circulation continuous core (sample) drilling. Particularly, reverse circulation continuous core (sample) drilling technology can effectively combine rock fragmentation drilling and core (sample) extracting which are originally two separated works to form integrated continuous drilling system of drilling and core (sample) extracting. Drilling and core (sample) extracting are completed synchronously, which can reduce auxiliary drilling works to the maximum level and increase pure drilling time. Reverse circulation continuous coring (sampling) can obtain rock core timely and quickly and know the stratigraphic change in time, which has the advantages of accurate and timely strata decision, good purity and representation of rock core and high coring ratio. When drilling in complex, easily collapsing and leakage formations, double wall drill rod (casing) and circulating irrigation fluid can protect the borehole walls.

• Clean all spare parts thoroughly with clean diesel oil.
• Check the nicks, burrs and cracks on piston surface, polish with sandpaper or replace it.
• Check the nicks, burrs and cracks on inner cylinder and inner hole of bushing, polish with sandpaper or replace them.
• Check the cracks and abrasions of spline sleeve. Install the spline sleeve on a new drill bit for torsion test and replace it if the loosening is more than 5mm.
• Check the nicks, burrs and cracks on cylinder base and core tube. Polish irregular shapes and replace them if necessary.
• Check the cutting transverse seam and cracks of O shaped sealing ring, replace it if necessary.
• Check the abrasions and damages of upper check valve. Check whether the check valve can slide freely around the cylinder base and core tube and check the sealing performance with upper joint.
• Measure the fit clearance between inner hole of piston and the top of core tube. If the fit clearance is more than 0.35mm, measure again with a new piston. If the fit clearance is still more than 0.35mm, replace core tube to meet requirements.
• Measure the fit clearance between piston and inner cylinder. If the clearance is more than 0.2mm, measure again with a new piston. If the clearance is still more than 0.2mm, replace parts to meet requirements.