Pressure & Pressure Measurement

is a type of stress which is exerted uniformly in all directions.

P = F/A P = Pressure in Pascal (lb/inch) F = Force in Newton (lb) A = Area in square meter

Increases as force increases or area decreases.

is the pressure due to weight of the atmosphere above the point where it is measured.

changes at different elevations because at higher elevation there is less weight of air than lower elevation areas.

is the actual height of the column of liquid. A container or vessel can be any shape but head is only determined by the height of liquid.

is the pressure due to head of liquid column.

P = ph P = pressure in (Pa or in psi) p = density (kg/cu m or lb/cu in) h = height (in m or feet)

is stating that the pressure applied to a confined static fluid is transmitted equal intensity throughout the fluid.

A hydraulic press

is pressure measured with a perfect vacuum as the zero point of the scale.

the units increase as the pressure increases.

cannot be less than zero and is unaffected by changes in atmospheric pressure.

is pressure measured with atmospheric pressure as zero point of scale. Negative gauge pressure is gauge pressure that is less than atmospheric pressure.

is the pressure measured below atmospheric pressure, referenced to atmospheric pressure.

is the difference in pressure between two points of measurement.

is a device for measuring pressure with a liquid filled tube.

is a manometer with a reservoir serving as one end and the measuring column at an angle to the horizontal to reduce the vertical height.

is a manometer with a vertical glass tube connected to a metal well, with the measuring liquid in the well at the same level as the zero point on the tube scale

is the ratio of the area of a well-type manometer tube to the area of the well.

is a manometer used to measure atmospheric pressure.

are a mechanical pressure sensor consisting of a thin flexible disc that flexes in response to a change in pressure.

is a mechanical pressure sensor consisting of two convoluted metal diaphragms with their outer edges welded to provide an empty chamber between them.

provide fairly large displacement motion that is useful in mechanical pressure gauges; the lesser motion of diaphragms is better in electromechanical sensors.

is a mechanical pressure sensor consisting of a hollow tube formed into a helical, spiral, or C shape.

is a mechanical pressure sensor consisting of a one-piece, collapsible, seamless metallic unit with deep folds formed from thin-wall tubing with an enclosed spring to provide stability, or with an assembled unit of welded sections

is a mechanical pressure sensor consisting of a differential pressure gauge with a piston that admits pressurized fluid at each end.

is a device that converts input energy into an output electrical energy.

is a pressure transducer with power supply and a device that conditions and converts the transducer output into a standard analog or digital output.

provides a discrete output when applied pressure reaches a preset level within the switch.

is a diaphragm pressure sensor with a strain gauge as the electrical output element.

is a diaphragm pressure sensor with a capacitor as the electrical element.

converts a differential pressure to an electrical (4 - 20mA) output signal.

transducer is a diaphragm or bellows pressure sensor with electrical coils and movable ferrite core as the electrical element.

is an inductance transducer consisting two coils wound on a single nonconductive tube.

is the internal distribution of forces within a body that balance and react to the loads applied to it.

is a fractional change in the dimensions of an object as a result of mechanical stress.

impulse line that is filled with a non-condensing gas

an impulse line filled with fluid that is compatible with the pressure-measuring device

is a hydraulic pressure calibrating device that includes a manually operated screw press, a weight platform supported by a piston, a set of weights, and a fitting to connect the tester to a gauge.