Abstract: The apparatus disclosed is a type of downhole pressure gauge to be used to measure and record pressure information about oil and gas wells. The apparatus measures fluctuations in pressure by means of a mechanical pressure sensitive device, such as a Bourdon tube, and records and stores this information by converting mechanical movement, associated with pressure changes as detected by the mechanical pressure sensitive device, into corresponding voltage changes across a potentiometer which are stored in an electronic memory board. The change in voltage over time corresponds to the change in well pressure over time, thereby providing important information to the well operator. Also disclosed is a method for measuring well pressure by means of combining a mechanical pressure sensitive device with an electrical system and an electronic memory board for storing the measurements.

Abstract: A differential pressure sensor comprises a pair of bourdon tubes disposed in an arrangement wherein deflections of the two bourdon tubes resulting from fluid pressures connected thereto take place in two opposite directions and the deflective extremities of the two bourdon tubes are linked to one another by a linkage, which linkage is coupled to a transducer that converts the displacement of the linkage to an electrical parameter such as the ohmic resistance, capacitance, reluctance, or resonance frequency as a measure of differential values between two pressures respectively connected to the two bourdon tubes.

Abstract: A control system and control device for controlling a heating unit and method of making the control device are provided, the control device having a rod and tube temperature sensing unit for providing linear motion of a part thereof along a substantially straight linear path in relation to the temperature being sensed by the temperature sensing unit and having a potentiometer unit provided with an electrical output producing unit operatively interconnected to the part of the temperature sensing unit so as to produce a variable electrical signal in relation to the temperature being sensed by the temperature sensing unit, the electrical output unit being movable along an arcuate linear path by the part of the temperature sensing unit. The potentiometer unit has a member provided with an arcuate surface, the electrical output unit being disposed in sliding engagement with the arcuate surface whereby the arcuate surface defines the arcuate path of movement of the electrical output unit.

Abstract: A Bourdon pressure gauge is provided with a direct-coupled electronic and visual readout. Specifically, the electronic and visual readouts are direct-coupled in that they are taken along a common linkage from the Bourdon tube. In addition, they are of comparable accuracy because the electrical readout is taken at a point of relatively small displacement amplification on the commmon linkage whereas the visual readout is taken at a point of substantial displacement amplification. In a preferred embodiment, the Bourdon tube is linked to a pivotally mounted linkage element having a cam head for driving a helicoidal gear. An electrical contact in cooperation with resistor disposed on the pivotally mounted element is used to take a variable resistance electrical readout, and a pointer for taking a visual readout is connected to the helicoidal gear.