Measurement Instruments Flashcards by grayson hartwick

Def : absolute zero

The moint at which molecular movement stops

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This is for?
Each stands for?

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Answer 1

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Def : boiling point

The point at which the vapor pressure of a liquid equals the atmospheric pressure resulting in the transition from liquid to gas

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This is for?
Components?

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This is for?
Components?

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When 2 bodies make contact what happens? (Thermal)

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4 types of thermowells?

-threaded
-flanged
-vanstone
-welded

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What should you put between the sensor and thermowell?

Heat transfer compound ie thermal conductive grease

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Def : 1 thermal time constant

How long it takes to get from 0 to 63.2% of the final temp

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What is the minimum recommended immersion length of a thermowell

6 x diameter

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When you require a thermowell in a small pipe what are the 2 mounting options

45 degree with tip pointing into the flow
on an elbow with rip pointing into the flow

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0 degrees Kelvin is

-273.5 ‘C

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0 degrees Rankine is

459.67 ‘ F

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If you are calculating linear expansion and copper 16.6/ degree C you multiply that by :

10^-6

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Thermometer A is ?

Total immersion

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Thermometer B is

Partial immersion ( to immersion mark)

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Thermometer C is?

Complete immersion

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How do you avoid parallax errors?

Look at straight on

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Thermometer class 1

Liquid other than mercury

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Thermometer class 2 is

Liquid-vapour interface

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Thermometer class 3 is

Gas filled

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Thermometer class 5 is

Mercury

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Def : head effect error

When the bulb is high and capillary is low the pressure from capillary cN cause error

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In a thermometer an invar wire is used for

Temp compensation in a mercury system

Thermometer: 2 for case compensation

2 capillaries or

What thermometer classification has the highest range

Class 3

Type E thermocouple colors

Purple

With thermocouples the ____ wire is always -

Red

Thermocouple type j colors

Conductor : white Jacket : black

Thermocouple type k colors

Conductor : yellow Jacket : yellow

Thermocouple type R colors

Conductor: black Jacket : green

Thermocouple type S colors

Conductor: black Jacket : green

Thermocouple type T colors

Conductor : blue Jacket : blue

A is

Reference junction, where the thermocouple wires are connected to cable could be in a jb or wherever

ICE point (rtd)

@ 0'c it has X ohm res

What is the most widely used and most linear material for rtds

Platnum

What is the difference between industrial grade and lab grade platinum rtds

Industrial 100 ohm ice point Lab 25.5 ohm ice point

Rtd European coefficient platnum

.003850 ohms/ohm'C

Rtds most common errors

- lead wire resistance - self heating - strain effect

What is a b c

How does a thermistor work

Very high ( 2 to 10k) ohm ice point that goes down as temp goes up

Thermistor disadvantages

Limited temp range -101 to 300 Not linear

LRV ma? URV ma?

Absorption for black body vs highly polished surface? Reflection?

I for black body , 0 for high polished Opposite for reflection

This is

What is D/S (pyrometer)

Distance / spot ratio for pyrometer

What is D/S (pyrometer)

Distance / spot ratio for pyrometer

How does flow leak detection work?

If flow quantity at 2 points is different then there is a leak

This is for

Process flow rate Qm = flow rate Qvs = volume of flow ps = density

Def : accuracy

How close an indicated value is to a recognized and accepted standard value ( ideal value)

Def : differential pressure

Pressure difference between 2 points

Def : head meter

A differential pressure measurement device

Def : integrator

A device that adds up the value of a quantity over a given amount of time

Def plainmeter

A device that measures the area of a plane surface by tracing its perimiter

Def : pressure head

The internal energy of a fluid due to its pressure

Def : primary element

The first element that responds to the measured variable ie flow sensor

Def : range

The region between the limits within which a quantity is measured

Def rangeability

The relationship between the range and minimum quantity that can be measured

Def : rate meter

A flow meter that indicates flow rate as a fluid passes through the meter

Def : 2ndary element

A device that receives the primary flow elements signal and converts it to a standard control signal Ex : I/P transducer

Def : span

The difference between the upper and lower range values

This is? It's range?

Turbulent

This is? It's range?

Transitional

This is ?

Reynolds #

What is pulsating flow?

Irregular or repeating variations in fluid flow rate

What is damping?

The progressive reduction or suppression of oscillations in a device or system

Piston type dampers aka

Snubbers

Snubbers do :

Delay the signal to the differential pressure element to prevent pressure spikes

Sintered metal pulsation dampers are:

Use mesh loking material to slow pressure spikes from the primary element

A ____ orifice plate should be used with a low Reynolds #

Quadrant

2 ways to reduce pulsations

- move flow meter away from pulsation source - install filters / hardware dampening devices

What is the advantage of a class 2 liquid/vapor temp system

Does not require ambient temp compensation

These are

U tube manometer

This is a

Mechanical differential pressure indicator

What do bellows differential indicators need due to temp effects on the bellows

Ambient temp compensation

What kind of diff pressure switch would you use for high pressure?

Piston

What does a pneumatic differential pressure transmitter do?

Sends a 20 to 100kpag or 3 to 15psig signal thats proportional to the measured diff pressure

What does an electronic differential pressure transmitter do

Sends an electronic signal ( usually 4-20) that is proportional to the measured diff pressure

What are the 2 types of transducers?

- strain guage: creates a diff in resistance when bent length ways - capacitance: changes distance between 2 plates

This is in WC

On a capacitance pressure transducer if you increase the distance between the plates the capacitance _____ ?

It goes down

This is?

These are? Uses?

Used with low reynolds # ( laminar flow)

These are? Uses?

Upping viscosity causes what with the Reynolds #

Reynolds goes down

🔺️ p to Q you ? Ie convert diff pressure to flow

Square root

Q to 🔺️p you Ie convert flow to diff pressure

X^2 it