Pressure Flashcards by antuaneth rodriguez

VEGA sells pressure products for process, hydrostatic and differential pressure measurements

True

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for basic applications (no digital output or display – fixed 4..20mA output)

BAR18 and BAR19

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compact sensors with light ring and Bluetooth access – limited features

BAR28/29

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compact sensors with display, light ring and Bluetooth access – limited features

BAR38/39

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for high temperature or caustic materials

BAR81

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for most applications (ceramic diaphragm)

BAR82

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for high pressure

BAR83

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for top down mounted hydrostatic pressure applications

BAR86 and BAR87

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for low cost hydrostatic applications (no yellow housing)

WELL52

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for traditional differential pressure applications – impulse lines or remote seals

DIF85

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memorize one thing

Pressure (psi) = 0.446 x SG x Height (feet)
or
Pressure (bar) = 0.1 x SG x Height (meters)

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You can determine the pressure range needed for the level your customer wants to measure

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You can determine the height of a liquid based on a pressure output and the fluids SG

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You can determine the SG of a product (when you have a fixed height) based on a pressure output

formula

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unitless ratio of a fluids density to the density of water at 68°F

Specific Gravity

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density of measured fluid ÷ 62.431 lb/ft3

Specific Gravity

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What they really want is resolution and repeatability. Remember to check the Turndown of an instrument to ensure you have enough resolution.

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full cell range ÷ desired measurement range

Turndown

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We have UNLIMITED turndown but recommend 20:1 or less

True

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Turndown is the ratio of the selected cell’s pressure range to the customer’s desired measurement range

True

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The VEGABAR 80 Series of instruments can be used for EDP (electronic differential pressure). A Primary (master) and Secondary (slave) relationship is established between two standalone pressure devices. These are two individual pressure units that measure pressure where they are mounted (sized for the pressure they will see). The only difference between the two units is the electronics for the secondary unit. The primary device with EDP activated, receives the pressure data from the secondary unit, does the math and outputs the differential.

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Any combination of BAR80 Series devices can be used for EDP

True

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Standard electronics can be activated or deactivated for EDP

True

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EDP- Only difference is the electronics module in the Secondary (SLAVE) unit

True

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EDP-Each unit is sized for the pressure it will see in the application

True

EDP - Need to look at Turndown in order to make sure there is enough resolution for the customer’s measurement

True

Pressure is read in all directions and the size or shape of the vessel is irrelevant. The pressure device is only concerned about the column of fluid above the pressure cell. It is not bothered by obstructions, foam, agitation or similar things that are constraints for other technologies.

True

Remote electronics on BAR80 devices allows for better access to electronics and display

True

VEGABAR 81

Oil filled diaphragm used for high temperature applications or with corrosive process fluids where special materials need to be used • Various diaphragm materials are available including stainless, Hastelloy, tantalum, gold, etc. • Long lead item as all versions are manufactured in Germany • Maximum temperature is reduced when used in vacuum (below atmospheric pressures) applications • Recommend a 3”-150# flange or larger to minimize oil expansion effects due to temperature • Can be used for EDP applications • Digital communication options include HART, Foundation Fieldbus, Profibus, and Modbus

VEGABAR 82

General purpose unit used for 80% of all applications • Ceramic diaphragm without oil filling (capacitive measurement) • High overload protection • Minimal re-calibration required • Ceramic is 10x harder than stainless steel – abrasion resistant • Can provide process temperature output (only accurate to ± 2°C) o Temperature measurement in the cell is really for VEGA’s benefit to identify thermal shocks o Not used for compensation of density due to temperature changes • Best cell type for applications involving vacuum • Single and double seal options available – belt and suspenders! • Can be used for EDP applications • Digital communication options include HART, Foundation Fieldbus, Profibus, and Modbus

VEGABAR 83

Use for high pressure applications • Three different cell types based on process connection and temperature requirements • Small process connections available • Can be used for EDP applications • Digital communication options include HART, Foundation Fieldbus, Profibus, and Modbus

VEGABAR 86 and VEGABAR 87

Top down mounted device for hydrostatic pressure measurements • Available with ceramic or metal diaphragms • Cab be configured with cable or tube • Can be used for EDP applications • Digital communication options include HART, Foundation Fieldbus, Profibus, and Modbus

VEGAWELL 52

Inexpensive Top down mounted device for hydrostatic pressure measurement • No yellow housing or local display – electronics are in the component that is submerged in the fluid • Very long cables available for direct mount to control cabinet • Ceramic cell (see VEGABAR82 comments above) • Available configurations can be all plastic, coated or stainless steel with different cable options • Digital communication option is HART

VEGADIF 85

Traditional differential pressure device for measuring the difference between two pressure points • Main applications use is with HIGH static pressure and SMALL measurement range • Available for use with capillary lines (remote oil filled seals) or impulse lines (using process fluid to transfer the pressure • Remote seals with capillaries are usually the same length to help with “speed of response”. You will usually see a coil of the capillary hanging at the low measurement point. • External environment affects the oil or process flowing in the connection lines – heat makes it expand and cool contract • Can have connections on one or both sides • Measures in absolute pressure but since we look at the difference it doesn’t matter • 3-way and 5-way valve manifolds are available

When selecting an ABSOLUTE pressure cell to measure vacuum, the best range to choose would be?

0...15 psi

VEGABAR with only 4...20mA output has no lighting.

True

What is the name of the 3-key operation with VEGABAR?

VDMA

The new VEGABAR series instruments are not suitable for hydrostatic measurements.

False

VEGABAR 29 has a ceramic measuring cell.

False

Metal separating diaphragms can be made of many different materials depending on application.

True

To minimize drift due to oil expansion and contraction, we recommend the minimum flange size to be?

3" (DN75)

The VEGA ceramic cell only uses medical white oil filling for hygienic applications.

False

About how many times harder are ceramic diaphragms than stainless steel?

The VEGA ceramic diaphragm can be used in ALL pressure applications.

False

Atmospheric pressure is ......

the pressure exerted by the air above

Gauge pressure is.....

the pressure measured relative to atmospheric pressure

Differential pressure is.....

the difference in pressure between two points of measurement

Hydrostatic pressure is.....

downward pressure exerted by fluid based on its density and weight

VEGA's Hydrostatic products are used in the following applications

Flotation Cells Top Down Storage Tanks Shipbuilding

About how many times harder are ceramic diaphragms than stainless steel?

Which of the following is NOT a linear level measurement using pressure?

inH2O TORR mmHG All of the above

True or False: EDP easily replaces DP systems if capillaries are less than 10 ft and range is less than 10 psi.

False

The specific gravity (SG) of a substance refers to its…

Density

True or False: VEGABAR 29 has a ceramic measuring cell

False

When should a “Double Seal” be suggested for the VEGABAR 82?

Always

Is a relative pressure measurement a differential pressure measurement?

Yes

True or False: Metal separating diaphragms can be made of many different materials, depending on the application.

True

What is VEGA’s recommended turndown ratio?

20:1

What is the name of the 3-key operation with the VEGABAR 10, 20, and 30 series sensors?

VDMA

With hydrostatic level, linearization is used if the sensor is NOT mounted in the tank bottom.

False

True or False: The VEGA ceramic cell diaphragm can be used in ALL pressure applications.

False

Which of the following instruments can NOT be configured for a differential pressure measurement?

VEGAWELL52

What is the turndown for a 5 … 10 psi measurement, using a 0 … 15 psi cell?

3:1

True or False: Currently, the VEGABAR 20 and 30 series sensors with only 4 … 20 mA output have no lighting.

True

Can pressure be used to measure density?

Yes

If the temperature of a process changes quickly, the hydrostatic pressure measurement output… [Select all that apply]

Increases | Decreases

True or False: The VEGABAR 82 with its 2 temperature sensors makes it the best instrument for measuring fluids with changing densities.

False

What is the pressure reading at full vacuum with an absolute measurement cell?

0 Bar

Which sensor is used for high temperature applications?

VEGABAR 81

What would be the best cell range to use for a requested measurement range of 110 … 350 psi? [Select all that apply]

0-300 psi | 0-25bar

Is a second current output available with an EDP configuration of a VEGABAR 81 and a VEGABAR 83?

Yes

If a hydrostatic measurement is not reading correctly, what could be the issue?

Temperature of the process Density of the process Pressure cell range

What is Absolute Pressure?

Measurement against a vacuum

Is process temperature an available output from all the VEGABAR 80 series instruments?

Can differential pressure be used to measure interface?

Yes

In an EDP setup can the pressure reading from both cells be assigned as HART variables?

When selecting a chemical seal, we should suggest a minimum flange size of…

3"-150#

True or False: The VEGADIF 85 measures in “Absolute” pressure ranges

True