Flow measurment

Flow rate can be expressed as

mass or volumetric flow rate

Mass flow rate

mass of material flowing per unit of time

Mass flow rate used to measure

flow rate of solids

Volumetric flow rate

volume of material flowing per unit of time

Volumetric flow rate used to measure

flow rate of liquids and gases

Standard conditions

14\.7 psi 15.5 C, 36% relative humidity

2 types of variable-area flow meters

rotameters and piston-type

Variable area flow meters provide a

direct visual reading of the flow rate

Variable-area flow meters increase the size of their _ as flow rate increases

orifice

Variable-area flow meters reading varies directly with the size of

their orifice

Differential-pressure flow meters include

orifice plates venturi tubes pitot tubes elbow taps

What happens to fluid pressure when velocity is increased

it decreases

Differential pressure sensors are _ flow sensing elements

primary

The flow rate when using a differential-pressure flow meter is inferred from an induced

pressure drop

Rotary-element flow meters include

propeller and paddle wheel flow meters

The rotating part of rotary-element flow meters are the

primary sensing element

Rotary element flow meteres comine

a rotating part and a conditioning circuit

The _ of a rotary element sensor is placed directly in the flow stream

rotating part

As the rotary part turns, it interrupts

a beam of light or magnetic field

When the rotary part of a rotary-element interrupts the beam of light it produces a

pulsed signal

The pulsed signal produced by a rotary flow meter is proportional to

the flow rate

Non disruptive flow meters include

magnetic flow meters, ultrasonic flow meters, Coriolis meter