An ambulatory infusion device for infusion of a liquid drug into a patient's body over an extended period of time and methods thereof are disclosed. The device includes a sensor assembly, which produces a sensor assembly output based on an infusion characteristic of the ambulatory infusion device and based on a supply voltage/current, and a supply unit which is coupled to a sensor of the sensor assembly and generates the supply voltage/current. A sensor testing unit detects a failure of the sensor assembly, wherein the sensor testing unit is coupled to the sensor assembly and the supply unit, and the sensor testing unit carries out a sensor testing sequence. The sensor testing sequence includes controlling the supply unit so as to produce a variation of the supply voltage/current, and determining whether the variation of the supply voltage/current produces a corresponding variation of the sensor assembly output.

Ambulatory infusion device with sensor testing unit

A control switch incorporates a solid state transducer, a strain gauge. The transducer responds to a local environmental condition, such as fluid level, or pressure and exhibits a parameter change which can be detected as an electrical output. Control circuits coupled to the transducer can sense the parameter change and switch a source of electrical energy to a load in response thereto.

Strain gauge pump control switch

The present disclosure relates to pressure sensors. In one illustrative embodiment, the pressure sensor may include a pressure sensor assembly having pressure ports on opposite sides of the pressure sensor assembly. The pressure sensor may include a protective housing including a first housing member and a second housing member defining a cavity for securely housing the pressure sensor assembly. The protective housing may include a first port coupled to one of the pressure ports of the pressure sensor assembly and a second port coupled to the other pressure port of the pressure sensor assembly. In some cases, the protective housing may include one or more aligning features, one or more positioning features, and a boss, which can include two or more bumps, on each side of the cavity around the pressure ports.

Pressure sensor assembly

Disclosed herein is a vertical pressure sensor. The vertical pressure sensor includes a pressure application unit having a diaphragm to which strain gauges are attached, a socket unit surrounding a circumference of the diaphragm of the pressure application unit, the socket unit having a through hole, first to fourth electrode terminals provided at the upper end of the socket unit in a Wheatstone bridge circuit pattern, one end of each of the electrode terminals exposed through the through hole being electrically connected to a corresponding one of the strain gauges by wire bonding, the other end of each of the electrode terminals protruding from the upper end of the socket unit to constitute an electrode tip, a circuit board connected to the first to fourth electrode terminals to convert a pressure value into an electrical signal, and electrode rods connected to the circuit board to transmit the electrical signal outside.

Vertical Pressure Sensor

The invention discloses a resistor testing apparatus. The apparatus comprises a four-point resistor testing device, a resistance meter, a thermometer, a tubular furnace, a gas cylinder, an air exhauster, an air inlet flange and an air exhaust flange, wherein the four-point resistor testing device comprises a resistance testing probe assembly and a sample bench assembly which are movably connected through a tubular clamp; the resistance testing probe assembly is provided with resistance testing probes; the sample bench assembly is provided with a sample bench and a temperature measuring probe; and the resistance testing probes abut tight against the upper surface of the sample bench under effects of the bite force of the tubular clamp. The use of the four-point resistor testing device improves the accuracy of the resistor testing apparatus provided by the invention, at the same time, during measurement of a sample to tested, on one hand, the sample to be detected is not polluted, and on the other hand, the problem of incapability of accurate control of the positions of the four probes due to silver slurry pasting in a conventional testing method can be solved. Besides, the measuring temperature is not restricted by an oxidation temperature of silver slurry anymore, and theoretically, the testing temperature can reach the melting point of a platinum wire, i.e., 1680 DEG.

Resistor testing apparatus

A system and method for pressure measurement may include the ability to readily produce a pressure measurement system. In one general aspect, pressure measurement 100 may include a signal-converting circuit 500 that includes a coupler 510, a signal biaser 550, and a signal span adjuster 560. The coupler is operable to receive a pressure-representative signal, and the signal biaser includes a thermally-insensitive voltage divider that facilitates biasing the pressure-representative signal. The signal span adjuster is coupled to the coupler and the signal biaser and includes a thermally-insensitive voltage divider that facilitates adjusting the span of the pressure-representative signal.

David F. Lepine

Papers

System and method for pressure measurement