Pressure Measurement Devices Quiz

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Questions and Answers

What is a primary advantage of using Bourdon tube pressure gauges?

They are highly sensitive to shocks and vibrations.

They are ideal for low-pressure measurements.

They can only measure high-pressure systems.

They provide accurate results and are cost-effective. (correct)

What is a significant limitation of Bourdon tube pressure gauges?

They are incompatible with high-pressure applications.

They cannot be adapted for electrical outputs.

They respond slowly to pressure changes. (correct)

They can measure precision accurately.

In which industries are diaphragm pressure gauges primarily utilized?

Construction and automotive.

Petrochemicals, pharmaceuticals, and food processing. (correct)

Electronics and telecommunications.

Consumer goods and retail.

What characteristic of diaphragm pressure gauges allows them to measure highly viscous media?

They are equipped with a diaphragm isolator. (B) Signup and view all the answers

What is the initial action when pressure is applied to the diaphragm in a diaphragm pressure gauge?

The diaphragm deforms and compresses the working medium. (C) Signup and view all the answers

What issue does the Bourdon tube face due to its low displacement?

It requires an amplification mechanism. (B) Signup and view all the answers

Which of the following statements is true regarding Bourdon tubes?

They can be modified for electrical outputs. (D) Signup and view all the answers

Why should direct measurement of certain fluids be avoided when using diaphragm pressure gauges?

They can cause damage to the diaphragm and gauge. (C) Signup and view all the answers

What is the primary function of a bellows pressure gauge?

To measure the pressure of gases or liquids (D) Signup and view all the answers

How does a bellows pressure gauge indicate pressure changes?

Through mechanical translation of bellows movement (C) Signup and view all the answers

What characteristic of the bellows is critical for its function in pressure measurement?

It is a flexible, cylindrical structure (A) Signup and view all the answers

What component of the McLeod Gauge serves as the zero reference point?

The reference capillary tube (A) Signup and view all the answers

What happens when the mercury level in the McLeod Gauge exceeds the cutoff point?

It cuts off the entry of applied pressure to the bulb (D) Signup and view all the answers

In what kind of applications are bellows pressure gauges commonly used?

Laboratory settings or low pressure measurements (B) Signup and view all the answers

What is the role of the piston in a McLeod Gauge?

To elevate the mercury level for pressure measurement (D) Signup and view all the answers

What is the mechanism by which bellows respond to pressure changes?

Expansion and contraction (B) Signup and view all the answers

What is the primary function of the wiper arm in a potentiometric pressure sensor?

To convert mechanical deflection into a resistance measurement (B) Signup and view all the answers

What type of device is commonly used as the detecting element in a potentiometric pressure sensor?

A Bourdon tube (D) Signup and view all the answers

What is one of the major drawbacks of potentiometric pressure sensors?

Mechanical wear leading to errors (A) Signup and view all the answers

How can resistance changes in a potentiometric pressure sensor be effectively utilized?

They can be converted into a standard voltage or current signal. (B) Signup and view all the answers

Why do potentiometric pressure sensors have hysteresis errors?

As a consequence of the wiper bearing on the element with some force (B) Signup and view all the answers

How does the design of a wire-wound potentiometer contribute to electrical noise?

Making and breaking contact with turns of wire causes extra electrical signals. (A) Signup and view all the answers

What allows for a lower level of noise in certain types of potentiometers?

Utilizing a non-conducting ceramic surface with deposited resistance material (D) Signup and view all the answers

What principle does an inductive pressure transducer use to convert pressure into an electrical signal?

Inductance (B) Signup and view all the answers

What should you do after making adjustments to a pressure gauge?

Document the original and final readings after calibration. (D) Signup and view all the answers

What is the first step in reading pressure from a pressure gauge?

Wear appropriate safety gear. (C) Signup and view all the answers

Why is it important to vent or bleed trapped air from the pressure line?

To prevent erroneous readings. (A) Signup and view all the answers

What is the primary focus of ASME standard B40.100?

Guidelines on pressure indicating devices and accessories. (A) Signup and view all the answers

Which instrument is NOT mentioned as a type used in field environments for pressure measurement?

Digital voltmeters (A) Signup and view all the answers

What should you do if the needle on the gauge is fluctuating rapidly?

Wait for the reading to stabilize. (A) Signup and view all the answers

What aspect is essential for ensuring process safety and accurate measurements as per the content?

Regular calibration of pressure gauges (C) Signup and view all the answers

Which of the following is NOT a valid unit for measuring pressure on a pressure gauge?

miles per hour (B) Signup and view all the answers

What should be checked visually before taking a pressure reading?

The gauge for signs of damage. (B) Signup and view all the answers

When preparing a gauge for calibration, which element is unnecessary?

Electronic display (B) Signup and view all the answers

What do PTC 19.2 standards primarily provide guidance on?

Pressure measurement accuracy in performance testing (A) Signup and view all the answers

What could parallax error cause when reading a pressure gauge?

A misreading due to the angle of observation. (D) Signup and view all the answers

What is NOT a factor in determining the choice of pressure measurement method?

Desired aesthetic of the gauges (B) Signup and view all the answers

When should you record the reading from a pressure gauge?

During routine checks or logging. (D) Signup and view all the answers

Which of the following is a documented benefit of following systematic calibration procedures?

Identification and correction of inaccuracies (C) Signup and view all the answers

The methods for pressure measurement include protocols for what aspect?

Data transmission and collection (A) Signup and view all the answers

Study Notes

Bellows Pressure Gauge

Used to measure the pressure of gases or liquids.
Uses a flexible metal bellows that expands and contracts in response to pressure changes.
This movement is translated into a pressure reading on a dial.
Often used in applications requiring high sensitivity and accuracy, such as laboratory settings.

McLeod Vacuum Gauge

Used to measure vacuum pressure.
Also serves as a reference standard to calibrate other low pressure gauges.
Components include a reference column, bulb, and measuring capillary.
Mercury level is raised in the gauge to cut off the entry of the applied pressure.

Bourdon Tube Pressure Gauges

Not ideally suited for low pressure or vacuum measurements.
Advantages include accuracy, simplicity, low cost, and ability to be modified for electrical outputs.
Limitations include slow response to pressure changes, hysteresis, sensitivity to shocks and vibrations, and inability to be used for precision measurements.

Diaphragm Pressure Gauge

Consists of a diaphragm isolator and a general pressure gauge.
Suitable for measuring pressure of corrosive, high temperature, and high viscosity media.
Used in industries like petrochemicals, alkalis, and food production.

Potentiometric Pressure Sensor

Converts pressure into a resistance measurement using a Wheatstone bridge circuit.
Uses a Bourdon tube to move a wiper on a potentiometer, changing the resistance as the pressure changes.
Simple and inexpensive, with a strong output signal.
Used in low-performance applications like dashboard oil pressure gauges.

Inductive Pressure Transducer

Converts pressure into an electrical signal through the principle of inductance.

Standards for Pressure Measurement

ASME B40.100: Guidelines on pressure gauges, diaphragm seals, and pressure limiter valves.
ASME PTC 19.2: Instructions for determining pressure values in support of ASME Performance Test Codes.
Both standards provide methods, instruments, and guidance for accurate pressure measurement.

Calibration of a Pressure Gauge

Regularly calibrate pressure gauges to maintain accuracy and ensure safety.
Calibration procedure involves comparing the gauge to a reference standard (deadweight tester or precision digital calibrator).
Document the original readings, reference standard readings, adjustments made, and final readings.

Reading Pressure from a Gauge

Wear appropriate safety gear.
Ensure the system is stable and the gauge is appropriate for the application.
Inspect the gauge for damage and ensure it is within its calibration date.
Avoid parallax error by standing directly in front of the gauge.
Note the reading on the scale, estimating values between marks.
Write down the pressure reading and units.
Take a second reading for confirmation.

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Description

Test your knowledge on various pressure measurement devices including bellows pressure gauges, McLeod vacuum gauges, and Bourdon tube pressure gauges. Explore how these devices function, their applications, and their advantages and limitations in different settings.