Dynisco Instruments LLC

John A Czazasty

Michael P Leonardi

Leo E Barron

Kevin Craig

John R Biagioni

Matthew Lockwood

Francis A Galler

Methods and apparatus are disclosed for correcting for gravitational force variation in measuring the melt flow index of a polymer at a location. For example, some embodiments may involve determining a value representing an extent to which gravitational force at the location varies from standard gravity, such as based at least in part upon the latitude of the location. The value may be used in correcting the melt flow index measured for the polymer using a plastometer at the location.

Correcting for gravitational force variation in measuring the melt flow index of a polymer

Rheological measurement systems for use with systems including pressurized polymer melts and/or other viscous materials are described. In one embodiment, a rheometer is connected to an associated system with a bent, curved, or bendable tube to permit the rheometer to measure rheological properties in locations where the rheometer could not otherwise be located due to the presence of obstructions. Embodiments including rigid straight tubes for connecting a rheometer to an associated system are also described. In another embodiment, a flow-through rheometer is connected to an industry standard ½-20 thermowell aperture that is typically used for attaching temperature and pressure probes to a vessel containing a viscous material such as an extruder or injection molding system. The rheological measurement systems described can have improved tube resistance and thermal strength.

Rheological measurement system with improved tube resistance and thermal strength

Methods and apparatus are disclosed for correcting for gravitational force variation in measuring the melt flow index of a polymer at a location. For example, ample, some embodiments may involve determining a value representing an extent to which gravitational force at the location varies from standard gravity, such as based at least in part upon the latitude of the location. The value may be used in correcting the melt flow index measured for the polymer using a plastometer at the location.

Rheological measurement systems for use with systems including pressurized polymer melts and/or other viscous materials are described. In one embodiment, a rheometer is connected to an associated system with a bent, curved, or bendable tube to permit the rheometer to measure rheological properties in locations where the rheometer could not otherwise be located due to the presence of obstructions. Embodiments including rigid straight tubes for connecting a rheometer to an associated system are also described. In another embodiment, a flow-through rheometer is connected to an industry standard &#xbd;-20 thermowell aperture that is typically used for attaching temperature and pressure probes to a vessel containing a viscous material such as an extruder or injection molding system.

Rheological measurement system

Pressure sensors and their methods of use are described. In one embodiment, a pressure sensor includes a probe body and a capacitive sensor disposed at a distal end of the probe body. The capacitive sensor produces a sensing capacitance. The pressure sensor also includes a shunt capacitance. In the described pressure sensor, a change in the sensing capacitance due to dimensional changes associated with a temperature change is offset by a corresponding change in the shunt capacitance.

Capacitive pressure sensor with intrinsic temperature compensation

Pressure sensors and their methods of use are described. In one embodiment, a pressure sensor may include: a tubular probe body; a capacitive sensor disposed at the distal end of the probe body; a lead electrically coupled to the sensor extending along an interior space of the probe body; and at least one support formed of a material having a relatively low dielectric constant disposed within the probe body to support the lead and space the lead away from an inner wall of the probe body. This may help to minimize shunt capacitance and changes in shunt capacitance due to radial movement of the lead. In other embodiments, a pressure sensor may include a channel formed in a wall of the probe body, a temperature sensor disposed at a distal end of the probe body, and a temperature sensor lead disposed in the channel and connected to the temperature sensor.

Capacitive pressure sensor

Pressure sensors and their methods of use are described. In one embodiment, a pressure sensor includes a pressure deflectable diaphragm end formed of a first material with a first coefficient of thermal expansion, and a relatively non-deformable component formed of a second material having a second coefficient of thermal expansion. The pressure deflectable diaphragm end and the non-deformable component form a first and a second portion of a capacitor. An intermediate component separates, or is disposed between, the pressure deflectable diaphragm end and the relatively non-deformable component. The intermediate component is formed of a material with a coefficient of thermal expansion that is less than the first coefficient of thermal expansion which may help minimize changes in span with temperature. In other embodiments, a pressure sensor includes an intermediate circuit located between a distal end of the pressure sensor and a remotely located circuit enclosure including a main circuit.

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Norton, MA, United States of America

John A Czazasty