Abstract: A strain gauge includes: a substrate; a dielectric layer on the substrate; a thin film electrical circuit on the dielectric layer and having input/output terminals; another layer disposed on the electrical circuit; the dielectric layer forming a first seal on one side of the electrical circuit, the another layer forming a second seal on a second side of the electrical circuit, the first and second seals having structure such that: in a first instance prior to exposure of the strain gauge to an autoclave cycle, the electrical circuit is productive of a first output voltage in response to a first input voltage; and in a second instance subsequent to exposure of the strain gauge to at least 10 autoclave cycles, the electrical circuit is productive of a second output voltage in response to a second input voltage, the first and second input voltages being equal, and the first and second output voltages being equal within a 15% shift in zero offset.

Abstract: A strain gauge includes: a substrate; a dielectric layer on the substrate; a thin film electrical circuit on the dielectric layer and having input/output terminals; other layers disposed on the electrical circuit; the dielectric layer forming a first seal on one side of the electrical circuit, the other layers forming a second seal on a second side of the electrical circuit, the first and second seals having structure such that: in a first instance prior to exposure of the strain gauge to an autoclave cycle, the electrical circuit is productive of a first output voltage in response to a first input voltage; and in a second instance subsequent to exposure of the strain gauge to at least 25 autoclave cycles, the electrical circuit is productive of a second output voltage in response to a second input voltage, the first and second input voltages being equal, and the first and second output voltages being equal.

Abstract: A strain sensor assembly is configured to detect one or more of forces applied to a structure having a recess. The strain sensor can include at least a pair of opposed strain gauge members that extend from the support member. Each strain gauge member defines a support portion carried by the support member and a biasing portion. The support portion includes at least one strain gauge sensor. The biasing portion is configured to bias against a wall of the recess of the structure when the strain sensor assembly is disposed in the recess. The strain sensor assembly is configured such that the at least a pair of strain gauge members form an interference fit with the wall of the recess when the strain sensor assembly is inserted in the recess.

Abstract: A flowmeter has a one-piece conduit with an outer surface and an inner surface that define a wall thickness therebetween, and first and second transducers, where each transducer is disposed external of or integral with the one-piece conduit, in signal communication with an interior volume of the one-piece conduit, and relative to each other such that each transducer can send and receive an acoustic signal to the other transducer. The one-piece conduit includes a plurality of acoustic noise attenuating features integrally formed with at least one of the outer surface and the inner surface and disposed between the first and second transducers, each of the features being configured and oriented to disturb a propagation direction of a parasitic acoustic wave that will propagate in the wall of the one-piece conduit in response to activation of at least one of the transducers.

Abstract: A differential pressure sensor positioned adjacent a pressure chambers separated by a nozzle. Flow in a conduit is determined by detecting the pressure on either side of a nozzle. Changes in pressure are proportional to a change in flow. An integrated differential pressure sensor having different pressure detecting portions with strain gauges thereon detects differences in deflection of each pressure sensor portion resulting from change in fluid flow. A bridge circuit detects changes in the signals from the two different pressure sensor portions creating a differential which is proportional to a change in liquid flow. The present invention reduces the need for calibration of pressure sensors and improves the detection of fluid flow. The invention can detect small changes in fluid flow and is particularly applicable to the medical field where, small fluid flows must be measured or determined accurately.

Abstract: A flowmeter has a one-piece conduit with an outer surface and an inner surface that define a wall thickness therebetween, and first and second transducers, where each transducer is disposed external of or integral with the one-piece conduit, in signal communication with an interior volume of the one-piece conduit, and relative to each other such that each transducer can send and receive an acoustic signal to the other transducer. The one-piece conduit includes a plurality of acoustic noise attenuating features integrally formed with at least one of the outer surface and the inner surface and disposed between the first and second transducers, each of the features being configured and oriented to disturb a propagation direction of a parasitic acoustic wave that will propagate in the wall of the one-piece conduit in response to activation of at least one of the transducers.

Abstract: An integrated fluid sensor combining bubble and occlusion detection. A housing having a channel with three sides holds a tube containing a fluid flow. An ultrasonic transmitter and ultrasonic receiver retain the tube on two opposing sides. Placed between the two opposing sides is a third side containing a pressure sensor. The pressure sensor contacting the surface of the tube detects changes of pressure within the tube due to changes in fluid flow so as to detect occlusions. The restraining of the tube between the opposing ultrasonic transmitter and ultrasonic receiver confine the tube so that a resulting increase in pressure is detected by the pressure sensor. A reduction in the size of devices for detecting fluid flow or bubbles is made possible.

Abstract: An ultrasonic flow meter permitting easy insertion and removal of a tube or conduit. A partial ring transducer or partial cylinder transducer is used to permit easy insertion and removal of a flexible tube in an ultrasonic flow meter for measuring fluid flow. In another embodiment a split ring or split cylinder transducer is used to facilitate easy removal and insertion of a tube or conduit in which fluid flow is to be measured. In another embodiment a clamping system is used to securely hold and couple a tube or conduit within the ultrasonic flow meter system. The present invention is conveniently adapted to hold flexible tubes and in particular disposable flexible tubes often used in the medical industry.

Abstract: A differential pressure sensor positioned adjacent a first pressure chamber and a second pressure chamber separated by a nozzle. Flow in a conduit is determined by detecting the pressure on either side of a nozzle. Changes in pressure are proportional to a change in flow. An integrated differential pressure sensor having different pressure detecting portions with strain gauges thereon detects differences in deflection of each pressure sensor portion resulting from change in fluid flow. A bridge circuit detects changes in the signals from the two different pressure sensor portions creating a differential which is proportional to a change in liquid flow. The present invention reduces the need for calibration of pressure sensors and improves the detection of fluid flow. The present invention has many applications and can detect small changes in fluid flow and is particularly applicable to the medical field where in many procedures, small fluid flows must be measured or determined accurately.

Abstract: A differential pressure sensor positioned adjacent a first pressure chamber and a second pressure chamber separated by a nozzle. Flow in a conduit is determined by detecting the pressure on either side of a nozzle. Changes in pressure are proportional to a change in flow. An integrated differential pressure sensor having different pressure detecting portions with strain gauges thereon detects differences in deflection of each pressure sensor portion resulting from change in fluid flow. A bridge circuit detects changes in the signals from the two different pressure sensor portions creating a differential which is proportional to a change in liquid flow. The present invention reduces the need for calibration of pressure sensors and improves the detection of fluid flow. The present invention has many applications and can detect small changes in fluid flow and is particularly applicable to the medical field where in many procedures, small fluid flows must be measured or determined accurately.