4AE3 U9 C2 Test Hard 25

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Questions and Answers

Which of the following methods is used to check the accuracy of pressure gauges through their entire measurement ranges?

Dead-weight tester (correct)

Test gauge (master gauge) comparison

Hydraulic comparator

Needle valve

Which of the following methods is a less accurate, but still valid method of testing a pressure gauge?

Hydraulic comparator (correct)

Dead-weight tester

Needle valve

Test gauge (master gauge) comparison

Which of the following is a practical means of restricting pulsations in the line leading to the pressure gauge?

Rubber bulb compression

Felt plug compression

Needle valve (correct)

Glycerin flow

Which of the following is a potential cause for loss of accuracy in pressure gauges?

All of the above Signup and view all the answers

Which of the following methods is used to compare the reading of a boiler pressure gauge to that of a test gauge while the boiler is in service?

Test gauge (master gauge) comparison Signup and view all the answers

Which of the following is true about the pressure gauge in the remote water-level indicator shown in Figure 26?

The pressure gauge measures the pressure in the water space of the boiler. Signup and view all the answers

What is the purpose of the condensing pot in the remote water-level indicator?

To maintain a fixed head of water on the upper side of the diaphragm. Signup and view all the answers

Which of the following is true about the differential pressure sensor (DP-cell) shown in Figure 27?

The DP-cell varies the transmitter output signal based on changes in level. Signup and view all the answers

What is the purpose of the high side transmitter connection in the differential pressure level measurement setup?

To provide a constant head to the DP-cell. Signup and view all the answers

In an open tank, how is the DP-cell bellows connected to accurately measure the liquid level?

One side of the bellows is connected to the bottom of the tank and the other side is left open to the atmosphere. Signup and view all the answers

Which of the following is an advantage of ultrasonic transducers attached to the outside of a pipe for flow measurement?

They do not contact the process fluid. Signup and view all the answers

Which type of flow meter is used to accurately measure the mass flow rate of a fluid, compensating for density changes?

Coriolis flow meter Signup and view all the answers

How does a Coriolis flow meter measure the mass flow rate of a fluid?

By inducing vibration in two parallel tubes and measuring the difference in distance between them. Signup and view all the answers

In which industries are Coriolis meters commonly used for flow measurement?

Pharmaceutical and food industries Signup and view all the answers

What types of fluids can a Coriolis meter accurately measure?

Viscous fluids and slurries Signup and view all the answers

Which of the following is true about optical pyrometers?

They measure temperature by comparing the brightness of a filament to that of the temperature source. Signup and view all the answers

What is the purpose of the red optical filter in an optical pyrometer?

To filter out unwanted visible light wavelengths. Signup and view all the answers

What is the main advantage of infrared thermometers over optical pyrometers?

They can measure temperature at a distance. Signup and view all the answers

What is the range of temperatures that infrared thermometers can measure?

-40°C to 800°C Signup and view all the answers

What is a limitation of infrared temperature detectors?

They can only measure surface temperatures. Signup and view all the answers

Which type of hygrometer measures the change in capacitance on a metal oxide as the relative humidity changes?

Capacitive hygrometer Signup and view all the answers

Which type of hygrometer is fairly economical, durable, and has reasonable accuracy?

Capacitive hygrometer Signup and view all the answers

Which of the following gases are commonly measured using non-dispersive infrared (NDIR) detection?

Carbon monoxide and carbon dioxide Signup and view all the answers

What is the purpose of continuous emission monitoring systems (CEMS)?

All of the above Signup and view all the answers

Which of the following gases is NOT typically monitored in a continuous emission monitoring system (CEMS)?

Methane Signup and view all the answers

Study Notes

Pressure Gauges

The entire measurement range of a pressure gauge is checked using a calibration test bench.
A less accurate method of testing a pressure gauge is by comparing it with a master gauge.
Pulsations in the line leading to a pressure gauge can be restricted using a pulsation dampener.
Loss of accuracy in pressure gauges can be caused by incorrect installation, vibration, and corrosion.

Remote Water-Level Indicators

The pressure gauge in a remote water-level indicator is used to measure the pressure of the water column.
The condensing pot in a remote water-level indicator is used to collect and condense steam, allowing the pressure gauge to measure the water level.

Differential Pressure Sensors

A differential pressure sensor (DP-cell) is used to measure the difference in pressure between two points.
The high side transmitter connection in a differential pressure level measurement setup is used to connect the DP-cell to the high-pressure side of the tank.
In an open tank, the DP-cell bellows is connected to the bottom of the tank to accurately measure the liquid level.

Flow Measurement

Ultrasonic transducers attached to the outside of a pipe can measure flow rate without disrupting the flow.
Coriolis flow meters are used to accurately measure the mass flow rate of a fluid, compensating for density changes.
A Coriolis flow meter measures the mass flow rate of a fluid by detecting the twist of the flow tube caused by the fluid's flow.
Coriolis meters are commonly used in the oil, gas, and chemical industries.
Coriolis meters can accurately measure the flow rate of liquids, gases, and slurries.

Temperature Measurement

Optical pyrometers measure the temperature of an object by detecting the radiation emitted by the object.
The red optical filter in an optical pyrometer reduces the effect of ambient light.
Infrared thermometers have an advantage over optical pyrometers in that they can measure temperature in a more direct and accurate way.
Infrared thermometers can measure temperatures ranging from -20°C to 3000°C.
A limitation of infrared temperature detectors is that they can be affected by the emissivity of the object being measured.

Humidity Measurement

Capacitive hygrometers measure the change in capacitance on a metal oxide as the relative humidity changes.
Resistive hygrometers are fairly economical, durable, and have reasonable accuracy.

Gas Measurement

Non-dispersive infrared (NDIR) detection is used to measure the concentration of gases such as CO, CO2, and CH4.
Continuous emission monitoring systems (CEMS) are used to monitor the emissions of pollutants such as NOx, SO2, and CO.
Oxygen is not typically monitored in a continuous emission monitoring system (CEMS).

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Description

Quiz on Gauge Selection and Visual Indications for Normal Process Pressure in Energy Plant Instrumentation and Controls. Test your knowledge on selecting gauges for accuracy and understanding visual indications for normal process pressures.