The Foxboro Company

John P Angelosanto

George E Sgourakes

Edwin L Karas

Roger E Powell, Ii

Simon Korowitz

Steven D Lantagne

Barry T Malloy

A selectively pressured housing apparatus comprising a body, a wall member, an aperture, and a mounting seat. The body has a chamber therein extending along a first axis, is open at a first axial end and a second axial end, and has a port extending along a second axis transverse to the first axis. The port communicates with the chamber. The wall member is inside of the body and extends transverse to the first axis and parallel to the second axis and divides the chamber into first and second compartments, axially spaced along the first axis. The port communicating with the chamber is in the second compartment. The aperture extends through the wall member and connects the first and second compartments. The mounting seat is on the wall member and extends circumferentially about the aperture for removably and replaceably seating an element with a selected pressure seal to the wall member. According to one preferred embodiment, the first and second compartments are employed for housing process electronics associated with a differential pressure transmitter.

Pressure sealed housing apparatus and methods

Pressure transmitter housing

A differential pressure measuring system comprising a transmitter for a pressure-measuring instrument connected to a control room by a two-wire transmission line carrying a d-c signal powered from the control room and representing the measured pressure. The instrument includes a reference pressure device of the falling-ball type, wherein a ball is first lifted to an upper position and then allowed to descend under the force of gravity to produce a reference pressure pulse for calibrating the instrument span. The lifting device for the ball is a two-coil magnetic actuator powered by current from the two-wire transmission line, and is operable at a sufficiently low current to be classified intrinsically safe. The reference pressure device is supported by an adjustable mounting providing two degrees of freedom for movement so as to permit ready adjustment of the device orientation to assure alignment with the force of gravity.

System for calibrating the span of pressure measuring instruments

A differential-pressure transmitter having a range diaphragm and a slack diaphragm to receive process pressures and to apply such pressures to an interior sealed chamber containing a fill-liquid. A vertically-oriented tube containing liquid communicating with the instrument fill-liquid contains a ball movable by gravity down through the liquid to create a reference-pressure pulse directed to the range diaphragm to provide for checking instrument performance. A relatively large weight is suspended from the ball to increase the effect of gravity on the ball, so as to increase the magnitude of the reference-pressure pulse. A flexible seal-and-pivot connection is provided at the top of the tube to permit substantial inclinations of the instrument relative to vertical without interference with the wall of the tube. The additional weight is in one embodiment divided into vertically-separable segments to provide for successive bottoming of the segments as the weight descends, to provide a stepped pressure pulse. Errors due to change in static pressure are avoided or reduced by special compensating arrangements.

Reference pressure devices for calibrating pressure-measuring instruments

Growing community of inventors

North Attleboro, MA, United States of America

John P Angelosanto