Rosemount Inc.

Thomas P Peterson

Gerald R Cucci

James E Walish

Lee A Mattison

A process control instrument adapted to provide an output indicative of a parameter of a process fluid is disclosed. The process control instrument is designed to be attachable to a flange having a first passageway filled with process fluid. A body of the process control instrument has an opening adjacent to the first passageway adapted to receive process fluid from the first passageway. A seal positioned in the opening and attached to the body at a seal outer diameter is adapted to prevent process fluid from leaking from the first passageway and the opening past the flange.

Self energizing process seal for process control transmitter

In a pressure transmitter, a central region of an isolator diaphragm with a substantially flat shape at an undeflected position near room temperature has a depressed shape at a deflected position at a colder temperature. The isolator diaphragm is over a shaped concavity in a transmitter body with a concave shape which corresponds to the depressed diaphragm shape to reduce output error.

Isolator for pressure transmitter

A transmitter that provides an output indicating pressure difference between a line pressure and atmosphere outside the transmitter is made intrinsically safe by coupling the sensor cavity as well as other cavities where ignition can occur to atmosphere only through flame quenching paths. The opening in the transmitter housing in which the sensor is mounted has a plug including a sensor cavity that holds the sensor, and a fitting which is couplable to the pressure line. An isolator is used for transmitting the process pressure to the sensor through an isolator diaphragm acting on an incompressible filling the sensor cavity and transmitting pressure through a hole that is shaped to provide a flame quenching path. The passageway flame isolates the sensor from the process fluid line. The opposite side of the sensor is connected to atmosphere only through paths which are flame quenching because of the passageway shape. The plug is an assembly that can be made easily inserted and removed, and provides intrinsic safety even if there is failure of some of the components such as the isolating diaphragm or welds holding portions of the plug together.

Pressure transmitter with flame isolating plug

An isolating mount provides vibration isolation for a sensor that is sensitive to external vibration about a rotational axis thereof at low frequencies, and translational vibrations in all axes at high frequencies. The isolation mount comprises a frame surrounding the sensor, and includes a plurality of columnar or beam members which are flexible in shear and stiff in compression. The beam members have longitudinal axes which lie in a common plane, also defined by the X-Y axes of the sensor. Connector members to couple desired beam members between the frame and the sensor and other connector members couple other beam members from the frame to the main support structure. The beam members flex in both the X and Y axis and also the Z axis, which is perpendicular to the common plane, but because the beam members are very stiff in compression, the resistance to any rotational movement about the Z axis is high. The columnar members are made up of a plurality of generally parallel metal shims which are molded together with a suitable elastomeric material and wherein the shims are spaced to obtain the desired flexing in shear and stiffness in compression for the mounting.

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Chanhassen, MN, United States of America

Thomas P Peterson