Abstract: A method and apparatus for continuously monitoring fluid level in an oil well, by measuring changes in the weight of the oil well tubing which result from changes in the buoyancy of the tubing caused by the rise and fall of fluid level within the oil well. In the apparatus of the invention, a transducer is either affixed to the downhole tubing of the oil well, or alternatively, is affixed to the drive head support structure of a well having a progressive cavity well pump. The transducer continuously senses changes in the weight of the tubing as the buoyancy of the tubing changes in proportion to the rise and fall of fluid level within the well. The transducer is preferably connected to a control unit which, in turn, is connected to the pump motor and which functions to automatically control the pump motor as a function of fluid level within the well.

Abstract: A strain gage apparatus that includes a unique mounting mechanism which enables the apparatus to be directly mounted on a load-bearing structure without having to modify the structure thereby making the apparatus particularly useful for measuring the weight of articles and materials disposed within various types of structures as, for example, tanks and hoppers.

Abstract: A clamp-on structural strain-gage sensor that is mounted to dynamic load-bearing structures, such as sucker-rod type oil well pumps, to produce an electrical output proportional to the deflection of such structures. The apparatus uniquely includes an active electronic temperature correcting circuit to provide compensation for the erratic effects caused by uneven thermal heating of the load-bearing structure.