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.