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A dead weight tester (DWT) is a calibration standard method that uses a piston cylinder on which a load is placed to make an equilibrium with an applied pressure underneath the piston. Deadweight testers are secondary standards which means that the pressure measured by a deadweight tester is defined through other quantities: length, mass and ...
Ultrasonic inspection may be substituted for the pressure test, which is usually a hydrostatic test and may be either a proof test or a volumetric expansion test, depending on the cylinder design specification. Test pressure is specified in the stamp markings of the cylinder. The results of a correctly performed pressure test are final. [31] [32]
Liquid-column pressure gauges have a highly linear calibration. They have poor dynamic response because the fluid in the column may react slowly to a pressure change. When measuring vacuum, the working liquid may evaporate and contaminate the vacuum if its vapor pressure is too high. When measuring liquid pressure, a loop filled with gas or a ...
Automatic calibration - A U.S. serviceman using a 3666C auto pressure calibrator. An automatic pressure calibrator [13] is a device that combines an electronic control unit, a pressure intensifier used to compress a gas such as Nitrogen, a pressure transducer used to detect desired levels in a hydraulic accumulator, and accessories such as ...
An open (differential) mercury pressure gauge. A mercury pressure gauge is a type of manometer using mercury as the working fluid. The most basic form of this instrument is a U-shaped glass tube filled with mercury. More complex versions deal with very high pressure or have better means of filling with mercury.
The vessel is filled with a nearly incompressible liquid – usually water or oil – pressurised to test pressure, and examined for leaks or permanent changes in shape. Red or fluorescent dyes may be added to the water to make leaks easier to see. The test pressure is always considerably higher than the operating pressure to give a factor of ...
Uniformity is a quality attribute indicating good workmanship. Trained welders are taught to keep the bead the same size at the beginning of the weld as at the end. If the bead gets too wide, the welder increases the speed of welding travel. If the bead gets too narrow or if the weld puddle is lost, the welder slows down the speed of travel.
A permanent downhole gauge (PDG) is a pressure and/or temperature gauge permanently installed in an oil or gas well. [1] These gauges are typically installed in the tubing in the well and can measure the tubing pressure, annulus pressure, or both.