Abstract: 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.

Abstract: 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.

Abstract: Flow through connectors and pressure sensing devices as well as their methods of use are described. In some instances a pressuring sensing device may include a ceramic body with a flow path extending through the ceramic body and at least one non-ceramic body attached to the ceramic body. The at least one non-ceramic body may include one or more attachment features formed therein and the flow path extends through the at least one non-ceramic body as well.

Abstract: Flow through connectors and pressure sensing devices as well as their methods of use are described. In some instances a pressuring sensing device may include a ceramic body with a flow path extending through the ceramic body and at least one non-ceramic body attached to the ceramic body. The at least one non-ceramic body may include one or more attachment features formed therein and the flow path extends through the at least one non-ceramic body as well.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: High temperature pressure sensing devices and methods are disclosed. In some embodiments, a high temperature pressure sensor including intrinsic zero output and span correction versus temperature is disclosed. In addition, ways in which to improve high temperature performance through the use of intermediate circuits located towards the distal end of the high temperature pressure sensor as well as configurations to reduce thermally induced stresses within the pressure sensor are disclosed. The disclosed embodiments also detail ways in which to reduce signal loss due to various stray capacitances within the pressure sensor to improve signal fidelity and sensitivity.

Abstract: High temperature pressure sensing devices and methods are disclosed. In some embodiments, a high temperature pressure sensor including intrinsic zero output and span correction versus temperature is disclosed. In addition, ways in which to improve high temperature performance through the use of intermediate circuits located towards the distal end of the high temperature pressure sensor as well as configurations to reduce thermally induced stresses within the pressure sensor are disclosed. The disclosed embodiments also detail ways in which to reduce signal loss due to various stray capacitances within the pressure sensor to improve signal fidelity and sensitivity.

Abstract: High temperature pressure sensing devices and methods are disclosed. In some embodiments, a high temperature pressure sensor including intrinsic zero output and span correction versus temperature is disclosed. In addition, ways in which to improve high temperature performance through the use of intermediate circuits located towards the distal end of the high temperature pressure sensor as well as configurations to reduce thermally induced stresses within the pressure sensor are disclosed. The disclosed embodiments also detail ways in which to reduce signal loss due to various stray capacitances within the pressure sensor to improve signal fidelity and sensitivity.

Abstract: One aspect is a pressure transducer package comprising a housing, a diaphragm, a support disposed in the housing and a sensing element disposed in the housing between the diaphragm and the support so that the pressure from the environment acts on the diaphragm to compress the sensing element. The sensing element comprises at least one substrate having a coefficient of thermal expansion greater than 4 ppm/k. In another aspect, the sensing element comprises at least one substrate formed of a first material and an epitaxial layer of a second material having a lower coefficient of thermal expansion. In a further aspect, the support abuts the housing at a spherically-shaped interface to compensate for misalignment between the support and the sensing element to ensure that the sensing element is evenly loaded.

Abstract: One aspect is a pressure transducer package comprising a housing, a diaphragm, a support disposed in the housing and a sensing element disposed in the housing between the diaphragm and the support so that the pressure from the environment acts on the diaphragm to compress the sensing element. The sensing element comprises at least one substrate having a coefficient of thermal expansion greater than 4 ppm/k. In another aspect, the sensing element comprises at least one substrate formed of a first material and an epitaxial layer of a second material having a lower coefficient of thermal expansion. In a further aspect, the support abuts the housing at a spherically-shaped interface to compensate for misalignment between the support and the sensing element to ensure that the sensing element is evenly loaded.

Abstract: One aspect is a pressure transducer package comprising a housing, a diaphragm, a support disposed in the housing and a sensing element disposed in the housing between the diaphragm and the support so that the pressure from the environment acts on the diaphragm to compress the sensing element. The sensing element comprises at least one substrate having a coefficient of thermal expansion greater than 4 ppm/k. In another aspect, the sensing element comprises at least one substrate formed of a first material and an epitaxial layer of a second material having a lower coefficient of thermal expansion. In a further aspect, the support abuts the housing at a spherically-shaped interface to compensate for misalignment between the support and the sensing element to ensure that the sensing element is evenly loaded.

Abstract: A heater assembly for mounting around a fluid flow channel in an injection molding apparatus, the heater assembly comprising: an inner tube comprising a first heat conductive material having a first coefficient of thermal expansion, the inner tube having a selected longitudinal length, an inner surface, an outer surface; a first ring having an inner surface engaged around the outer surface of the inner tube along short selected length of the longitudinal length of the inner tube, the first ring comprising a second material having a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion; a heater mechanism that heats the inner tube to a selected elevated temperature.

Abstract: An injection molding apparatus and method are provided in which the rate of material flow during an injection cycle is controlled. According to one preferred embodiment, an injection molding apparatus is provided that includes a manifold, at least one injection nozzle coupled to the manifold, an actuator, and a valve pin adapted to reciprocate through the manifold manifold and the injection nozzle. The valve pin has a first end coupled to the actuator, a second end that closes the gate in a forward position, and a control surface intermediate said first and second ends for adjusting the rate of material flow during an injection cycle. Retracting the valve pin tends to decrease the rate of material flow during the injection cycle and displacing the valve pin toward the gate tends to increase the rate of material flow during the injection cycle.

Abstract: An injection molding apparatus and method are provided in which the rate of material flow during an injection cycle is controlled. According to one preferred embodiment, an injection molding apparatus is provided that includes a manifold, at least one injection nozzle coupled to the manifold, an actuator, and a valve pin adapted to reciprocate through the manifold and the injection nozzle. The valve pin has a first end coupled to the actuator, a second end that closes the gate in a forward position, and a control surface intermediate said first and second ends for adjusting the rate of material flow during an injection cycle. Retracting the valve pin tends to decrease the rate of material flow during the injection cycle and displacing the valve pin toward the gate tends to increase the rate of material flow during the injection cycle.

Abstract: A valve pin actuator is disclosed that includes a cylinder mounted to the clamping plate, a piston slidably mounted in the cylinder, and a valve pin assembly carried by the piston. A hydraulic or pneumatic circuit is provided for controlling the movement of the piston, and in turn translation of the valve pin between the seated and unseated positions. The valve pin assembly includes a first part removably secured to the piston so as to translate therewith, and a second part for receiving the valve pin and secured to said manifold. The actuator assembly enables removal of the clamping plate without removal of the valve pin assembly, and also adjusting of the valve pin without removal of the clamping plate. The assembly further provides a clearance between the piston and valve pin assembly, to accommodate expansion and movement of the manifold that would otherwise cause a side load to be exerted on the valve pin.

Abstract: The present invention includes a filtration apparatus for an injection molding machine where the injection molding machine includes a screw housed within a bore for generating molten polymer. A tip member extends axially from the screw. The tip member has radially extending upstream and downstream flanges positioned axially apart from each other. A filter encircles the tip member and is capable of filtering the molten polymer. An annular ring member encircles the tip member and is slidably positioned within the bore between the upstream and downstream flanges. The ring member is capable of sliding between the flanges for directing the molten polymer through the filter or preventing back flow of the molten polymer past the upstream flange.

Abstract: An air-cooled shaft seal comprises an annular body having an inner surface and an outer surface. One or more helical channels are formed on the inner surface. A plurality of external surfaces such as radial fins are disposed in axially spaced relationship on the outer surface, and extend radially in a direction away from a longitudinal axis of the annular body. The external surfaces present a substantially increased surface area through which heat energy is transferred from polymeric material contained in the seal to the atmosphere. The seal may be installed on one or shafts of a gear pump for transporting a viscous material under pressure.