摘要:
A semiconductor filter is provided to operate in conjunction with a differential pressure transducer. The filter receives a high and very low frequency static pressure attendant with a high frequency low dynamic pressure at one end, the filter operates to filter said high frequency dynamic pressure to provide only the static pressure at the other filter end. A differential transducer receives both dynamic and static pressure at one input port and receives said filtered static pressure at the other port where said transducer provides an output solely indicative of dynamic pressure. The filter in one embodiment has a series of etched channels directed from an input end to an output end. The channels are etched pores of extremely small diameter and operate to attenuate or filter the dynamic pressure. In another embodiment, a spiral tubular groove is found between a silicon wafer and a glass cover wafer, an input port of the groove receives both the static and dynamic pressure with an output port of the groove providing only static pressure. The groove filters attenuate dynamic pressure to enable the differential transducer to provide an output only indicative of dynamic pressure by cancellation of the static pressure.
摘要:
A semiconductor heterostructure based pressure switch comprising: first and second small bandgap material regions separated by a larger bandgap material region; a third small bandgap material region within the region of larger bandgap material, the third material region and larger bandgap material region defining at least one quantum dot; and, first and second electrodes electrically coupled to the first and second small bandgap material regions, respectively, wherein the electrodes are sufficiently proximate to said quantum dot to facilitate electron tunneling there between when a pressure is applied to the bandgap material defining the quantum dot.
摘要:
A fluid flow probe including: first, second and third pressure sensors; a first port for communicating a first pressure to the first pressure sensor; a second port for communicating a second pressure to the second pressure sensor, the second port being substantially oppositely disposed with respect to the first port, a third pressure port suitable for communicating a static pressure to the third pressure sensor; first and second outputs electrically coupled to the first and second pressure sensors, respectively, one of the first and second outputs indicative of a total pressure and the other of the outputs indicative of a base pressure; and, a third output electrically coupled to the third pressure sensor and indicative of the static pressure.
摘要:
A system for sensing at least one physical characteristic associated with an engine including a turbine having a plurality of blades turning inside a casing, the system including: a pressure sensor coupled substantially adjacent to the casing and including at least one output; a port in the turbine casing for communicating a pressure indicative of a clearance between the blades and casing to the pressure sensor; a cooling cavity substantially surrounding the pressure sensor; and, an inlet for receiving fluid from the engine and feeding the fluid to the cooling cavity to cool the pressure sensor; wherein, the pressure sensor output is indicative of the clearance between the blades and casing.
摘要:
A pressure sensor including: a deflectable diaphragm including a substantially central boss and channel; and, an optical waveguide having first and second arms, wherein the first arm is substantially aligned with an edge of the boss and the second arm is substantially aligned with an edge of the channel.
摘要:
A system and method for automatic analysis of temperature transition data over an area of a sample surface. The system relies on the use of a microfabricated probe, which can be rapidly heated and cooled and has a sharp tip to provide high spatial resolution. The system also has fast x-y-z positioners, data collection, and algorithms that allow automatic analysis of and visualization of temperature transition data.
摘要:
A method to prevent the catastrophic failure of electrical contacts of silicon piezoresistive transducers located on a silicon wafer at temperatures above 600° C. comprising the steps of using a lead-free glass frit to surround the contacts and bonding the sensor wafer to a glass wafer employing a lead-free glass and utilizing a modified electrostatic bonding technique to join the silicon wafer to the lead-free glass wafer to form a high temperature SOI device.
摘要:
The present invention relates to a system for detecting aerodynamic instabilities in a jet turbine engine having a pressure transducer mounted in the engine. The pressure transducer, welded to a circuit in signal communication with a controller, is adapted to send measured pressure readings from air in a combustion chamber to the controller. The controller, located in spaced apart relation from the engine, is adapted by software to detect pressure patterns from the pressure signals generated by the transducer that are indicative of a stall or surge. A series of fuel and air valves located with compression and combustion chambers of the engine are in signal communication with the controller. The controller in response to detecting pressure signals indicating a stall or surge is operative to signals in the valves to change the air flow, air angle, fuel flow or speed to reduce the possibility of a stall or surge.
摘要:
A resonating pressure transducer operable to measure an applied pressure by measuring changes in a resonant frequency is disclosed. The pressure transducer comprises a plurality of diaphragms formed in a wafer of semi-conducting material between two layers, wherein each of the diaphragms is divided into a plurality of electrically isolated sections; a cavity in one of the covering layers opposite a corresponding one of the diaphragms, a first via formed through a selected one of the layers enables application of a potential to selected ones of the diaphragm sections; and a second via formed through a selected one of the layers enables transmission of a measure from selected ones of the diaphragm sections.
摘要:
A pressure sensing device produces an output proportional to applied pressure irrespective of vibration/acceleration of the device, which device also provides an output proportional only to vibration/acceleration of the device irrespective of the pressure.