Abstract: Apparatus for detecting fluid pound in a sucker-rod oil well, using values of sucker-rod position and of sucker-rod load to calculate a reference position and a selected load value. The apparatus continually updates the reference positions and selected load values to compensate for drift in characteristics of transducers used in determining rod load and rod position and for a gradual change in well characteristics. When the sucker-rod moves downward to the updated reference position, the actual rod load is checked against the updated selected value and a warning signal develops when the amount of load exceeds the updated selected value.

Abstract: Method and apparatus for checking a sucker-rod pumped well for defects by weighing the well. A load cell connected between the sucker-rod and a power unit develops a signal representative of the load on the sucker-rod. The sucker-rod load is checked with the rod and an associated downhole pump plunger in a stationary position. The load readings are corrected for load cell drift by a computer, and a corrected load value displayed on a digital display unit. The load readings are updated periodically and any changes in load reading can be used to determine the presence of a defect and to ascertain the type of defect in the pumping apparatus.

Abstract: Apparatus for selectively discharging load carriers at a predetermined one of discharge stations. The carriers are connected to an endless chain. The chain is made of links of approximate equal length, which are divided into segments of an equal number of links. The position of each carrier is determined by a control system that measures the actual length of segments of the chain and keeps a record of the lengths of the segments which extend between a reference point and the position of the each carrier. When the length of the chain between the reference point and the carrier equal the known distance along the chain path between the reference point and the preselected discharge station a mechanism is actuated to remove the load from the carrier.

Abstract: A method for measuring the length of segments of moving chain includes the steps of measuring the velocity of the chain by timing the interval a point on the chain moves a known distance and timing the interval between the sensing of one end of the segment at one point and the sensing of the opposite end of the segment at another point a known distance from said one point. A method is disclosed to track each carrier in a conveyor system by continuously measuring segments of the chain and maintaining a running total of the chain length between each carrier and a reference point. Apparatus in the conveyor system, including a chain length measuring station, is disclosed.