DEVICE FOR FLUSHING OF BOTTOM HOLE Russian patent published in 1995 - IPC

FIELD: drilling equipment. SUBSTANCE: device for flushing of bottom hole has body 1 with piston 2 and plunger 3 installed in it to form above-piston and under-piston spaces 5 and 6. Piston 2 with small diameter (plunger 3) is disposed in high-pressure chamber 4 hydraulically communicated with under-piston space 6 through channel 12 with check valve 13. Shut-off member 14 loaded with spring 15 is located in above-piston space 5. Seat 16 of shut-off member 14 is made in partition 17 separating above-piston space 5 into upper and lower spaces, hydraulically communicated with drill string-borehole space. Piston 2 is spring-loaded relative to partition 17. Body additionally has braking chamber 23 and accumulating chamber 11 hydraulically communicated with high-pressure chamber 4 through check valve. Installed in partition 17 is force hydraulic member 22 for interaction with piston 2 and shut-off member 14. The latter has spring-loaded rings from inner and outer sides. Slots are made on shut-off member 14 from its end to seating surface. Low-pressure fluid stream constantly acts on bottom hole flowing over channel 7 from under-piston space 6 and acts on bottom hole through low-pressure nozzle. High-pressure and low-pressure nozzles are directed in parallel to bottom hole to increase efficiency of action. EFFECT: higher efficiency of flushing due to increased time of action of high-pressure jet onto bottom hole. 3 cl, 4 dwg