Echometer 4 Horseshoe Dynamometer Transducer

A 4" OD horseshoe transducer is used to accurately measure the polished rod load and position. The 4" horseshoe transducer is installed between the pumping unit carrier bar and the permanent polished rod clamp. To install the 4" horseshoe transducer a temporary polished rod clamp is positioned on the polished rod about 4 inches above the stuffing box while the polished rod is at the bottom of the stroke. A temporary knock-off block is located on the stuffing box as the polished rod with the temporarily installed clamp is on the down stroke. Also on the down stroke, the motor is turned off. The momentum of the system causes the polished rod to continue downward until the temporarily installed polished rod clamp comes in contact with the knock-off assembly. The pumping unit brake is set when the polished rod is at the bottom of the stroke. This causes the permanently installed polished rod clamp that normally rests on the carrier bar to be several inches above the carrier bar. The 4" O.D. transducer is 3" high, and it is positioned into the free space between the carrier bar and the permanent polished rod clamp. The pumping unit brake is released causing the load to be transferred from the knock-off block to the carrier bar. Then the knock-off block is removed and the well is started again. Dynamometer tests can be performed after the well has stabilized or as desired.

The 4" horseshoe transducer very accurately measures polished rod load using 12 strain gauges which are mounted on three supporting members. Offloading or sideloading due to the carrier bar being tilted does not affect the accuracy of the load measurement.