Mks Instruments, Inc.

Steven D Blankenship

D Jeffrey Lischer

Paul D Lucas

Robert C Pandorf

Archibald J DeMone

Frank W Thomas

One or more reactive gases are introduced to a capacitance manometer at a particular area or areas of the diaphragm between the inner and outer capacitive electrodes so the error-inducing measurement effects of positive and negative bending are neutralized or minimized. Additionally, a guard structure may be used with the electrode structure of the capacitance manometer. The guard structure presents an area that is relatively insensitive to the diffusion of the gas into the diaphragm and the resulting changing surface tension, thus providing increased or optimal stability of the zero reading of the manometer. The guard may also provide electrostatic isolation of the electrodes.

Pressure sensor

An improved capacitive manometer comprises a diaphragm that is constrained relative to an electrode structure spaced from the diaphragm. An electrode support structure is arranged to support the electrode structure and comprises a compliant ring including at least three flexures integrally formed in the ring and angularly spaced around the alignment axis. The electrode support is clamped in place relative to the diaphragm at the locations of the compliant ring flexures.

Capacitive pressure sensor with improved electrode structure

An improved capacitive manometer includes a diaphragm including a common electrode and an electrode structure including a center electrode and ring electrode. The diaphragm is movable between (i) a zero position when the pressure on each side of the diaphragm is the same and (ii) a maximum differential position when the maximum measurable differential pressure is applied to the diaphragm. A support structure is arranged to support the diaphragm so that the diaphragm is constrained relative to the electrode structure. The common electrode is spaced from and axially aligned with the center and ring electrodes. The electrode structure is secured relative to the diaphragm at at least three clamping locations. The angle defined within each right plane containing a point of constraint of the diaphragm and the point of each clamping location relative to the plane of the diaphragm in the zero position is between 60&#xb0; and 90&#xb0;.

Capacitive pressure sensor

The disclosed pressure transducer assembly includes a body, a diaphragm, an insulating member, a conductor, a compressed member, and a support member. The body defines an interior cavity. The diaphragm is mounted in the body and divides the interior cavity into a first chamber and a second chamber. A portion of the diaphragm moves in a first direction in response to a pressure in the first chamber being greater than a pressure in the second chamber, and that portion of the diaphragm moves in a second direction opposite the first direction in response to the pressure in the second chamber being greater than the pressure in the first chamber. The conductor is disposed on the insulating member. The insulating member is disposed within the first chamber so that the conductor and the diaphragm form plates of a capacitor. The compressed member is disposed in the first chamber and generates a force that biases the insulating member towards the diaphragm. The support member is disposed between the diaphragm and the insulating member. The support member resists movement of the insulating member towards the diaphragm. The support member is characterized by a thickness and a cross-sectional width. The ratio of the thickness to the cross-sectional width is greater than one.

Capacitive pressure transducer with improved electrode support

The disclosed heated pressure transducer includes an external enclosure, a first thermal shell housed within the external enclosure, and a sensor housed within the first thermal shell. The transducer further includes a heater for heating the first thermal shell and a control unit for controlling the heater. A tube couples the sensor to a source of heated, pressurized gas and the transducer may further include a tube-heater that is controlled by the control unit for applying heat to the tube. The transducer may also include a second thermal shell housed within the external enclosure with at least a portion of the control unit being housed within the second thermal shell. A heater that is controlled by the control unit may be disposed proximal to the second thermal shell for heating that shell. An auxiliary heater disposed within the first thermal shell for heating the sensor may also be included. Two thermistors may also be included for measuring the temperature of the sensor and the first thermal shell.

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Melrose, MA, United States of America

Steven D Blankenship