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A.SZUDER

A.SZUDER. PRESSURE MEASUREMENT. A.SZUDER. Pressure measurement. Pressure driven equipment (IC engines, turbines, etc.)Pneumatic or Hydraulic mechanical elementsBiomedical applications (Blood Pressure, Barometric Chambers)Losses in pipes and ducts

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A.SZUDER

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    1. A.SZUDER

    2. A.SZUDER PRESSURE MEASUREMENT

    3. A.SZUDER Pressure measurement Pressure driven equipment (IC engines, turbines, etc.) Pneumatic or Hydraulic mechanical elements Biomedical applications (Blood Pressure, Barometric Chambers) Losses in pipes and ducts – energy efficiency Atmospheric conditions (weather forecast, altitude) Indirect measurement of flow rate or velocity Scuba diving Many, many more ...

    4. A.SZUDER PRESSURE MEASUREMENT Absolut, Differential Barometer Manometer

    5. A.SZUDER Absolute pressure

    6. A.SZUDER Barometer

    7. A.SZUDER Differential pressure

    8. A.SZUDER Types of pressures

    9. A.SZUDER Static And Dynamic Pressure

    10. A.SZUDER Static And Dynamic Pressure

    11. A.SZUDER Types of pressure transducers: Liquid Column manometers Elastic tubes, diaphragms, membranes (equipped with displacement or strain sensors) Semiconductor elements (with implanted stress elements) Piezoelectic elements (directly convert crystal lattice stress into voltage)

    12. A.SZUDER Liquid Column Manometers

    13. A.SZUDER Liquid Column Manometers

    14. A.SZUDER Inclined Manometer

    15. A.SZUDER Pressure transducers

    16. A.SZUDER Pressure transducers Elastic elements Changing pressure change the shape of the elastic element Shape changing is detected by a resistive or position transducer

    17. A.SZUDER Pressure transducers Elastic elements Changing pressure change the shape of the elastic element Shape changing is detected by a resistive or position transducer

    18. A.SZUDER Pressure Sensor range

    19. A.SZUDER Elastic Type Manometers

    20. A.SZUDER More Elastic types...

    21. A.SZUDER Dial-type Manometer

    22. A.SZUDER Diaphragm type manometers

    23. A.SZUDER Strain gauges used with Diaphragm

    24. A.SZUDER Strain gage based pressure cell When a strain gage, is used to measure the deflection of an elastic diphragme or Bourdon tube it becomes a comonent in apressure transducer Strain-gage transducers are used for narrow-span pressure and for differential pressure measurements. Essentially, the strain gage is used to measure the displacement of an elastic diaphragm due to a difference in pressure across the diaphragme If the low pressure side is a sealed vacuum reference, the transmitter will act as an absolute pressure transmitter. Strain gage transducers are availablefor pressure ranges as low as 1300 MPa

    25. A.SZUDER Capacitance based pressure cell Capacitance pressure transducerswere originally developed for use in low vacuum research. This capacitance change results from the movement of a diaphragm element (The diaphragm is usually metal or metal-coated quartz and is exposed to the process pressure on one side and to the reference pressure on the other. Depending on the type Differential pressure transducers in a variety of ranges and outputs of pressure, the capacitive transducer can be either an absolute, gauge, or differential pressure transducer. Capacitance pressure transducers have a wide rangeability, from high vacuums in the micron range to 70 MPa.

    26. A.SZUDER The potentiometric pressure sensor provides a simple method for obtaining an electronic output from a mechanical pressure gauge. The device consists of a precision potentiometer, whose wiper arm is mechanically linked to a Bourdon or bellows element. This type of transducer can be used for low differential pressure applications as well as to detect absolute and gauge pressures.

    27. A.SZUDER The resonant wire pressure transducer The resonant-wire pressure transducer was introduced in the late 1970s. a wire is gripped by a static member at one end, and by the sensing diaphragm at the other. An oscillator circuit causes the wire to oscillate at its resonant frequency. A change in process pressure changes the wire tension, which in turn changes the resonant frequency of the wire. A digital counter circuit detects the shift. Because this change in frequency can be detected quite precisely, This type of transducer can be used for low differential pressure applications as well as to detect absolute and gauge pressures. Resonant wire transducers can detect absolute pressures from 10 mm Hg, differential pressures and gauge pressures up to 42 MPa. Typical accuracy is 0.1% of calibrated span, with six-month drift of 0.1%

    28. A.SZUDER Piezoelectric sensors Piezoresistive pressure sensors are sensitive to changes in temperature and must be temperature compensated. Piezoresistive pressure sensors can be used from about 21 KPa to 100 MPa. Resonant piezoelectric pressure sensors measure the variation in resonant frequency of quartz crystals under an applied force. The sensor can consist of a suspended beam that oscillates while isolated from all other forces. The beam is maintained in oscillation at its resonant frequency. Changes in the applied force result in resonant frequency changes. The relationship between the applied pressure P and the oscillation frequency is: P = A(1-TO/T) - B(1-TO/T2) where TO is the period of oscillation when the applied pressure is zero, T is the period of oscillation when the applied pressure is P, and A and B are calibration constants for the transducer. These transducers can be used for absolute pressure measurements with spans from 0-100 kPa to 0-6 MPa or for differential pressure measurements with spans from 0-40 kPa to 0-275 kPa .

    29. A.SZUDER Magnetic pressure transducers These included the use of inductance, reluctance, and eddy currents. Inductance is that property of an electric circuit that expresses the amount of electromotive force (emf) induced by a given rate of change of current flow in the circuit. Reluctance is resistance to magnetic flow, the opposition offered by magnetic substance to magnetic flux. In these sensors, a change in pressure produces a movement, which in turn changes the inductance or reluctance of an electric circuit.

    30. A.SZUDER Optical pressure transducers Optical pressure transducers detect the effects of minute motions due to changes in process pressure and generate a corresponding electronic output signal. A light emitting diode (LED) is used as the light source, and a vane blocks some of the light as it is moved by the diaphragm. As the process pressure moves the vane between the source diode and the measuring diode, the amount of infrared light received changes. Optical pressure transducers do not require much maintenance. They have excellent stability and are designed for long-duration measurements. They are available with ranges from 35 kPa to 413 MPa and with 0.1% full scale accuracy.

    31. A.SZUDER Sensor/Cavity System Response (Helmholz Resonator)

    32. A.SZUDER Bourdon tube over pressure protection Most pressure instruments are provided with overpressure protection of 50% to 200% of range These protectors satisfy the majority of applications. Where higher overpressures are expected and their nature is temporary (pressure spikes of short duration—seconds or less), snubbers can be installed. If excessive overpressure is expected to be of longer duration, one can protect the sensor by installing a pressure relief valve. However, this will result in a loss of measurement when the relief valve is open.

    33. A.SZUDER Mechanical High pressure sensors In the case of the button repeater ( figA), the diaphragm can detect extruder pressures up to 10,000 psig and can operate at temperatures up to 4300°C because of its selfcooling design. It operates on direct force balance between the process pressure (P1) acting on the sensing diaphragm and the pressure of the output air signal (P2) acting on the balancing diaphragm. The pressure of the output air signal follows the process pressure in inverse ratio to the areas of the two diaphragms. If the diaphragm area ratio is 200:1, a 1,000-psig increase in process pressure will raise the air output signal by 5 psig. Another mechanical high pressure sensor uses a helical Bourdon element (Figure B). This device may include as many as twenty coils and can measure pressures well in excess of 10,000 psig. The standard element material is heavy-duty stainless steel, and the measurement error is around 1% of span. Helical Bourdon tube sensors provide high overrange protection and are suitable for fluctuating pressure service, but must be protected from plugging. An improvement on the design shown in Figure B detects tip motion optically, without requiring any mechanical linkage.

    34. A.SZUDER Vacuum mesurement Vacuum gauges in use today fall into three main categories: mechanical, thermal, ionization.

    35. A.SZUDER Vacuum mesurement

    36. A.SZUDER Semiconductor-type Sensors

    37. A.SZUDER Static Calibration

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