An arithmetic processing unit (30) included in a pressure change measuring apparatus (1) includes: a differential pressure calculation unit configured to obtain a pressure difference between an inner pressure of a cavity (10) and a pressure to be measured based on an output signal of a differential pressure measuring cantilever (4); a pressure-to-be-measured calculating unit configured to calculate the pressure to be measured based on a set inner pressure of the cavity (10) and the differential pressure calculated by the differential pressure calculation unit; a flow rate calculating unit configured to calculate a flowing quantity of a pressure transmission medium flowing into and out of the cavity (10) for every unit of a predetermined time period based on the differential pressure calculated by the differential pressure calculation unit; and an inner pressure updating unit configured to calculate the inner pressure of the cavity (10) after the predetermined time period based on the flowing quantity calculated by the flow rate calculating unit and a volume of the cavity (10), and to update, to the calculated inner pressure, a set value of the inner pressure of the cavity (10) to be used by the pressure-to-be-measured calculating unit.

An apparatus for applying pressure to a pipe and measuring internal pressure. The apparatus including jacket disposed on the pipe, one or more of a first set of strain gauges disposed on a wall of the pipe, one or more of a second set of strain gauges disposed on the wall of the pipe, and a temperature sensor disposed on the wall of the pipe. The pipe has an inner diameter, an outer diameter, and a length.

A pressure detection device of a liquid flow route is provided which detects a pressure of an arterial blood circuit consisting of a flexible tube, a portion of which is connected to a peristaltically-actuated tube that can cause an internal liquid to flow by being compressed in a radial direction and being peristaltically actuated in a longitudinal direction in a roller of a blood pump, and which enables a predetermined liquid to be circulated. The pressure detection device includes a load sensor that detects radial displacement of the peristaltically-actuated tube.

A pressure sensor which detects variation in pressure, the pressure sensor including a cantilever which bends according to a pressure difference between the inside and the outside of a cavity in a sensor main body, and a first gap, a second gap, and a third gap which are formed on a proximal end portion of the cantilever. The first to third gaps electrically partition the proximal end portion of the cantilever into a first support portion, a second support portion, a first displacement detection portion, and a second displacement portion in a second direction orthogonal to a first direction in which the proximal end portion and a distal end portion of the cantilever are connected to each other in plan view. The first and second displacement detection portions detect displacement according to the bending of the cantilever between the first and second support portion.

As a wellbore is extended into a formation, hydrostatic and hydrodynamic pressures change due to variations in drilling mud weight, fluid density, etc. Strain gauges downhole measure forces experienced by drilling equipment. During drilling, a strain gauge measures strain applied between the drill string and the formation. When off bottom, the strain gauge measures forces experienced by the drill string other than drilling forces. A pressure calculator converts off bottom strain gauge measurements into measurements of hydrostatic pressure for periods without fluid flow (i.e., when drilling motors are paused) and into measurements of hydrodynamic pressure for periods with fluid flow (i.e., when mud motors are operating). The pressure calculator correlates strain measurements (usually in voltages) to pressure based on a predetermined relationship for a given wellbore geometry (e.g., hole diameter, drill bit diameter, drill pipe diameter, etc.).

A thermal conductivity gauge measures gas pressure within a chamber. A sensor wire and a resistor form a circuit coupled between a power input and ground, where the sensor wire extends into the chamber and connects to the resistor via a terminal. A controller adjusts the power input, as a function of a voltage at the terminal and a voltage at the power input, to bring the sensor wire to a target temperature. Based on the adjusted power input, the controller can determine a measure of the gas pressure within the chamber.

A pressure sensor includes a sensor body which has a first surface and a cavity with an opening in the first surface, a cantilever which has a base end portion supported on the first surface and a distal end portion provided to form a gap from a peripheral edge of the opening inside the opening, is flexurally deformed according to a pressure difference between an inside and an outside of the cavity, and is formed of a semiconductor material, and a displacement measurement unit which measures a displacement of the cantilever vibrating according to the pressure difference at a frequency larger than a lower limit frequency f.sub.LOW (Hz) defined by Expression (1), where a width (m) of the gap is represented by G, a volume (ml) of the cavity is represented by V, and a proportional constant is represented by k.
f.sub.LOW=k.Math.(G.sup.2/V)(1)

A pressure sensor device for internal pressure monitoring in a hose, preferably an infusion hose, that is used for fluid transmission and that rests directly or indirectly on a pressure sensor housing. The hose is elastically deformable and connected via a contact side to a pressure transmission element located in the pressure sensor housing. The pressure transmission element transmits internal pressure changes absorbed via the contact side to a compressive force sensor for measurement. The contact side can have an elliptical shape, and the pressure transmission element can have a funnel-shaped extension, to make the pressure sensor device as robust as possible in terms of measurement accuracy, and independent of fluctuations in temperature and associated changes in material states.

Disclosed is a pressure and temperature sensor capable of precisely measuring a pressure. A sensor body, a diaphragm defining an accommodation space together with the sensor body, and a transmission substance charged in the accommodation space are provided, and a pressure measurement body and a temperature measurement body which is a separate body from the pressure measurement body are disposed in the accommodation space.

Methods, systems, and apparatuses are provided for detecting and determining conditions of and conditions within a fluid conduit.