Dynisco, Inc.

Mks Instruments, Inc.

Christopher P Grudzien, Jr

Robert A Malloy

James F Reilly

Louis Panagotopulos

A pressure sensor has a housing for receiving a fluid whose pressure is being sensed, and an electrode assembly and a diaphragm arranged to form a variable capacitor within the housing. In one embodiment, the electrode assembly includes a dielectric disk with a conductive electrode and a standoff being formed on a surface of the disk facing the diaphragm. A spacer ring is provided between the standoff and the diaphragm so that the thickness of the spacer ring sets the gap between the electrode of the electrode assembly and the diaphragm. In another embodiment, the electrode assembly is an integral unit that includes a housing and an electrode such that lower surfaces of the housing and the electrode are coplanar to each other. In this embodiment, the spacer is between the housing and the diaphragm such that the thickness of the ring sets the length of the gap.

Pressure sensor

A variable capacitance fluid pressure sensor of the type which includes a deflectable member includes a contaminant exclusion system which protects the deflectable member from both solid and non-solid fluid-borne contaminants. A system of traps disposed between the fluid inlet to the sensor and the deflectable member prevents deposition of process vapors in the fluid on the deflectable member and collects a variety of sizes of fluid-borne solid contaminants remote from the deflectable member.

Fluid pressure sensor with contaminant exclusion system

A capillary rheometer apparatus includes a housing, a plunger, the housing having a reservoir for receiving the plunger in a polymer melt, and a mechanism for blocking flow of the melt out of the reservoir. A driving mechanism is included for driving the plunger longitudinally within the reservoir to move one end of the plunger in contact with the melt. A diaphragm, which is coupled to the one end of the plunger, deflects in response to melt pressure in the reservoir. A mechanism, responsive to diaphragm deflection, determines pressure of the melt. Another mechanism is included for determining the temperature of the melt and a further mechanism is included for indicating longitudinal movement of the plunger. From such determinations, the PVT characteristics and the apparent shear viscosity characteristics of the polymer melt can be obtained.

Capillary rheometer plunger pressure transducer and measurement technique

An optical pressure transducer includes a body for supporting therein both an input optical fiber and an output optical fiber. A light source generates input light to the input optical fiber. A force responsive diaphragm is secured to the body and deflects in response to sensed pressure. A fixed reflector and a moveable reflector, which is attached to and moves with the diaphragm, are disposed in the optical path between the input and output optical fibers and reflect at least a portion of the input light from the input optical fiber to the output optical fiber. The amount of light reflected depends upon the deflection of the diaphragm. A system for monitoring and controlling the light source, including an optical detector in a feedback arrangement, is provided such that the amount of light generated by the light source remains constant and maximized.

Optical pressure transducer having a fixed reflector and a movable

Optical pressure transducer

A capillary rheometer plunger having a liquid-filled capillary passage extending within the plunger is removably housed in a heater block holder for maintaining temperature stability and minimizing temperature induced errors. The plunger is placed in the holder during purging, cleaning, reloading and packing the capillary rheometer with the polymer under test. The holder includes an electrically heated holder member disposed within an aperture of an outer shield and is provided with an aperture in which the plunger is removably received for heating. A base supports the shell. A temperature sensor disposed in the shell controls the temperature of the holder member at the temperature of the polymer under test.

Heater block holder for a capillary rheometer plunger pressure transducer

A capillary rheometer including a plunger pressure transducer assembly which contains a liquid metal fill capillary passage therein. When the plunger is urged downward onto the melted polymer, a diaphragm at the end of the plunger senses the pressure within the melted polymer and transmits this pressure to the liquid metal fill. An additional diaphragm disposed in the opposite end of the plunger pressure transducer assembly senses this transmitted pressure within the liquid metal fill for an accurate indication of the pressure therein.

An optical pressure transducer employing input and output optical fibers defining therebetween an optical path. The optical path is interrupted by a fixed reflector and a moveable reflector. The moveable reflector is secured by adjustment means to the diaphragm that is responsive to pressure being measured.

Growing community of inventors

Mansfield, MA, United States of America

Christopher P Grudzien, Jr