Differential Pressure Elements

Question 1

How does a DP develop as a fluid stream approaches a restriction?

Answer 1

As a fluid stream approaches the restrictor the pressure increases due to the stream impacting the restrictor. This causes the restrictor to increase the stream velocity decreasing the downstream pressure.

Question 2

What is the difference between primary and secondary elements?

Answer 2

A primary element produces the DP and the secondary measures that DP

Question 3

What causes the DP produced by a pitot tube?

Answer 3

Difference between duct or pipe pressure and static pressure

Question 4

How can you ensure that an Area-Averaging Pitot Station does not plug?

Answer 4

Employ a purging system

Question 5

Where would an annubar be employed?

Answer 5

When the velocity profile makes single point measurement difficult

Question 6

What primary element requires the least amount of upstream and downstream pipe diameters?

Answer 6

V-Cone

Question 7

What is the biggest advantage of using a venturi tube?

Answer 7

High pressure recovery

Question 8

What are the 3 advantages of using a flow nozzle?

Answer 8

1) High velocity fluid
2) Steam flow
3) Can handle entrained solids

Question 9

What are the 2 disadvantages of annubar flow elements?

Answer 9

1) Only used for clean gases and liquids
2) Requires an amplifier