FORMATION TESTER Russian patent published in 1995 - IPC

FIELD: equipment for testing oil and gas bearing formations. SUBSTANCE: formation tester consists of body including sub 1, branch pipes 2,3,4 and 5 and case of braking chamber 6. Branch pipe 2 accommodates admission ball valve unit. The latter has ball 7, seats 11 with packing rings 12, drive rod including rods 17,18 and 19, rod 50 of compensation valve, compensation valve located in space between rods 19 and 50. It is formed by equalizing bushing 46 of drive rod 19 of admission valve and recess 58 of rod 50 of compensation valve. Rod 50 of compensation valve has protrusion 56. Distance h between bottom 59 of recess 58 of rod 50 and end face 48 of drive rod 19 with flexible busing 46 of formation tester in stretched state relative to distance H between end face 61 of case 60 and end face 57 of projection 56 of rod 50 is determined by relation given in invention description. EFFECT: higher quality of testing due to improved reliability of valve operation control. 3 dwg