TYPES OF ORIFICE PLATE
(1)Concentric Orifice Plate
(2)Eccentric orifice plate(3)Segmental orificeplate(4) Quadrant Edge plate
Concentric Eccentric SegmentalQuadrant Edge
Orifice
ORIFICE PLATES
TYPES OF ORIFICE PLATE
Concentric :It’s thickness is 3.175 mm to12.70mm It consist of circular hole in the middle.
MOC:Nickal, Phosphorous,bronze.Accentric :Use :When the liq. Fluid consist dissolve gases in
higher quantity, the Accentric orifice plate is used.
In order to measure rate of flow by differential pressure there must be a method of creating two differential-pressure. this can be accomplished by placing a restriction in the pipe line that forces the fluid through a reduced area.
DIFFERENTIAL PRESSURE METERS
ORIFICE METER
Pipe
Liquid
Mercury
U-Tube Manometer
Restriction ElementPRINCIPLE:When the liquid, flows in the
pipe line, because of resistant of orifice plate, differential, pressure is
produced while is proportional to flow rate.
Restriction element
Pipe
ORIFICE METER
Advantages:
(1) It is easy to carry out without closing the process.
(2) It is used for any pipe size & flow rate
Venturimeter
Throat
Inlet
Low pressure tap
OUTLET
High pressure tap
Venturi - Meter
It operated on exactly the same principle as the orifice.
A venturi gives a definite improvement in power loses over an orifice and is often indicated
for measuring very large flow rates.The initial higher cost of venturi over an
orifice.
VARIABLE AREA METER ( ROTA METER )
Tapered glass metering tube
Float
Ring shaped area around float changes as float rises or falls
Inlet
OutletOutlet
Rotameter
Float :Usually made allu. , brass, bronze, nickel,
s.s. etc.Scale :
Marked on glass tube or close to metering tube.
Installation :Set vertically in pipe by means of
flanges along with inlet & outlet piping supported in brackets.
CONSTRUCTION:Rotameter tube is made of glass or metal.Glass metering tube is used for low pressure & temp. services.Glass tube is not useful for high pressure fluid. so in this case, metal tube is used.
ROTAMETER
• when no fluid through meter, float rests at bottom.• as fluid starts to flow, float rises & allows to flow
through annular space between float edge & metering tube.
• when flow rate increases, float moves up & flow rate decreases, it fall in tube.
• at certain fluid flow rate , float stabilize at certain position.
• usually float has slots. so that it rotate & centre in the tube. so this meter is called as rotameter.
WORKING
PITOT TUBE
Stuffing Box
Static flow pressure connection
Impact high pressure Connection
Packing Nut
Tube
Pitot Tube
PipeStatic Opening
Impact Opening
Flow
PITOT TUBE
PRINCIPLE:
It works on the principle of differential flowmeter.
USE:
Its main use is measurement of fluid velocity.
PITOT TUBE
OPERATING PRINCIPLE:
When solid body is the middle of pipe is steady & flow streaming is lower direction, flow velocity is decrease. Due to pressure of body this decreasement is zero at the body. This point is known as stagnation point.
Kinetic head is lossed & static head is gain so difference measured between normal flowline & stagnation point
PITOT TUBE
Advantageous of pitot tube :
(a) It is easy to remove pitot tube from pipe line.(b) There are no pressure loss in the pitot tube.(c) It is easy to install.
PITOT TUBE
Disadvantageous of pitot tube :
(a) Accuracy is very less in the pitot tube(b) It is not use for sticky material(c) It is sensitive for upstream disturbance.