Abstract: An apparatus and method for controlling a surging flow in a closed conduit is characterized by a moveable flow restrictor element disposed within the closed conduit and responsive to a control signal to restrict the fluid flow therewithin to a damped flow rate. The control signal is generated by a controller element which responds to first and second signals input thereto. The first signal is representative of the instantaneous fluid flow rate within the closed conduit. The second signal is functionally related to the first signal and representative of the damped flow rate within the conduit.

Abstract: Pneumatic apparatus for monitoring conditions of the drilling fluid circulating system of a well being drilled. A pneumatic signal having unequal duration times and representative of the rate of movement of the circulating pump is transmitted through a repeater valve and converted by a frequency divider into a pair of pneumatic signals having equal duration times. These signals actuate a series of metering systems which generate rate pressures representative of conditions of the circulating system. These rate pressures are displayed to the operator through independently calibrated and adjusted gauges.

Abstract: An apparatus for use with a borehole monitoring system which senses downhole well conditions in a wellbore having a pump and a mud flow line characterized by short term pressure fluctuations for circulating drilling mud down the well. The apparatus includes a housing having a first chamber and a second chamber in pressure communication with the mud line. The chambers are separated by a resilient member capable of movement in response to pressure surges in either chamber and producing a corresponding pressure surge in the other chamber. The apparatus also includes a differential pressure sensor in pressure communication with both chambers and capable of producing an output corresponding to the pressure differential between the chambers.

Abstract: A pneumatic apparatus for measuring the rate of movement of one object with respect to another. A pneumatic signal functionally related to the displacement of the object whose rate is being measured is generated, differentiated and recorded. The apparatus is adapted to reset itself automatically if the rate exceeds a predetermined amount. The record produced by the apparatus may be a bar graph or a continuous curve reading directly in the rate of movement being measured.