INTRODUCTION TO ELECTRONIC INSTRUMENTATION Chapter 5 INTC 1305 – 01 FLOW Vern Wilson

Review of Chapter 4 – Level Innage/outage Floats Interface Meniscus Density and head

FLOW MEASUREMENTS Chapter 5

Pipeline Meter Run Pipeline Meter Run #117 avi

Gas Separator

Summary of Flow – These instruments measure FLOW Fluid in motion Always from hi to lo p Molecules continually change Laminar - streamline Turbulent Obstructions mess up smooth flow Usually turbulent flow is consistent

Reynolds Number Identifies type of flow – turb or lam R = v x d x ϱ / μ v = velocity d = diameter ϱ = density μ = viscosity > 4000 = turbulent > 10,000 = fully turbulent < 2,000 = laminar Between 2,000 and 4,000 = transient

Flow Measurements Positive Displacement Percentage flow Measures absolute volumes Uses chambers of known volume Percentage flow Based on known flow at 100% Volumetric Flow GPM MCFD Mass Flow Pounds per time

Flow Sensing Differential Pressure Bernoulli – page 109 As velocity increases the static pressure of the fluid decreases Flow devices: Orifice (differential flow meters), Venturi, Flow Nozzles, pitot tubes, Annubar tubes, rotameters, electromagnetic meters, turbine meters, mass flow meters

ORIFICE PLATES Simple pressure drop Flat upstream – bevelled downside Set in tapped flanges

Orifice Plates

FLOW PATTERN THROUGH ORIFICE

VENTURI TUBES – 5.3.2 Higher cost but lower op costs Smooth cone shaped As speeds increase in the throat the pressure is reduced according to Bernoulli

Venturi Tube

FLOW NOZZLE 5.3.3 Extended tapered inlet Can be inserted into a flange Allow higher flow then orifice plates - twice Can handle slurries Less $ than venturi but more than orifice

Flow Nozzle

PITOT TUBES 5.3.4 Measures impinging pressure Disadvantage – measures flow at only one point Can’t measure laminar flow ANNUBAR or MULTI PORT Pitot with several ports

Pitot Tube

ROTAMETERS Based on gravity and impinging pressure Tapered flow tube with a float Flow tube calibrated to flow Only give an estimate of flow Float can be magnetized inside steel tube Designed for specific small range

Rotameter

ELECTROMAGNETIC METER Or Magmeters – no metal in body Measures electrically conductive liquids Generally water based Obstruction free – noninvasive Food and drug use Based on Faraday’s law of induction – an electrical potential is produced when a conductor moves at a right angle through a magnetic field

TURBINE METER Flow tube with free spinning turbine One blade is magnetic Induction pick up coil Each pulse indicates a rotation of the turbine Simply multiply a K factor times the number of sensor pulses

Turbine Meter

MASS FLOW METER CORIOLIS METER They measure density through temperature and pressure Tube vibrates and twists giving a velocity difference which is converted to flow

DIFFERENTIAL (D/P) TRANSMITTER Most common Responds to pressure Flow is proportional to square root of dp

MEASUREMENT FLOW MEASURED IN: GPM POUNDS PER MINUTE

GPM EXERCISE An injection program requires 100 barrels of injection fluid per day. How many GPM is equal to 100 barrels per day? First: There are 42 gallons per barrel Second: Convert to GPM

POUNDS PER MINUTE EXERCISE We are pumping mud that weighs 10.9 pounds per gallon at 4 barrels per minute. How many pounds per minute are we pumping? First: Determine how many pounds are we pumping – 4 barrels = 42 gals/barrel Second: Determine how many pounds per minute.

Orifice Chart 0.500 x 4” Temperature 95ºF Gravity = 0.73 Fb = 50.23 Fpb = 1.0055 Ftb = 1.0000 Fg = 1.1704 Ftf = 0.968 Fr = 1.0703 Fpv = 1.0159

Orifice Chart C’ = 62.22 3 PM Friday 3 PM Saturday Hw = 68” Ps = 220 psig Q = C’√hw*Ps Q = 62.22 * √68*(220+14.7) = 7860 CuFt/Hr 189 MCFD

Handbook

F Factors – Orifice Coefficient Fb

Fpb Ftb Fg

Orifice Chart C’ = 62.22 1 PM Tuesday 1 PM Wednesday Hw = ” Ps = psig Q = C’√hw*Ps Q = 62.22 * √ *( +14.7) = CuFt/Hr MCFD