HYDRAULIC TEST EQUIPMENT EQUIPPED WITH BOREHOLE TELEVISION MONITORING FRONT AND SIDE SIMULTANEOUSLY

摘要

PROBLEM TO BE SOLVED: To select a most appropriate position based on the information of internal conditions of hole by providing a borehole television(BTV) which can observe front and side simultaneously. SOLUTION: A water shield packer 12 for setting a test space, a BTV camera 15 for observing the inside of a borehole, and the like are disposed in the hole of a test equipment. The double-convex lens 30 and back-convex lens 31 in the camera 15 has a very short focal length and the imaging position is adjusted by varying the thickness of an intervening transparent spacer 32. A light beam from a forward object PF is condensed through the lens 30 and enters through the spacer 32 the lens 31, and since the focal point of lens 30 is located within the focal point of lens 31, the light beam is extended to produce an inverted virtual image. A light beam from a sideward object PS is reflected on the surface of lens 31 to produce a reflected virtual image PS' which is formed on a common plane CP together with the PS'. Consequently, the front and side images can be observed simultaneously over the entire circumference using a single TV camera disposed on one optical axis without altering the focal point.