Page 90 - Applied Process Design for Chemical and Petrochemical Plants Volume I

Fluid Flow 77

Table 2-3
Resistance Coefficients for Valves and Fittings

Approximate Range of Variation for K
Fitting WCe of Variation
90 Deg. Elbow Regular Screwed 220 per cent above 2 ir,ch size
Regular Screwed +40 per cent below 2 inch size
Long Radius, Screwed +25 per cent
Regular Flanged i35 per cent
Long Radius, Flanged +30 per cent
45 Deg. Elbow Regular Screwed +lo per cent
Long Radius, Flanged +lo per cent
180 Deg. Bend Regular screwed i25 per cent
Regular Flanged i35 per cent
Long Radius, Flanged i30 per cent
Tee Screwed, Line or Branch Flow i25 per cent
Flanged, Line or Branch Flow i35 per cent
Globe Valve Screwed k25 per cent
Flanged +25 per cent
Gate Valve Screwed +25 per cent
Flanged +50 per cent
Check Valve Screwed +30 per cent
Flanged +200 per cent
-80 per cent
Sleeve Check Valve Multiply flanged values by .2 to .5
Tilting Check Valve Multiply flanged values by .13 to .19
Drainage Gate Check. Multiply flanged values by .03 to .07
Angle Valve Screwed +20 per cent
Flanged +50 per cent
Basket Strainer +5Q per cent
Foot Valve k50 per cent
Couplings +50 pe- cent
Unions +5Q per cent
Reducers +50 per cent
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_
~_____.~~ _________ _ . ~ ___ ~ ~
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Notes on the use of Figures 2-12 A and B, and Table 2-3
1. The value of D given in the charts is nominal IPS (Iron Pipe Size).
2. For velocities below 15 feet per second, check valves and foot valves will be only partially open and will exhibit higher values of K than that shown
in the charts.
3. Reprinted by permission Hydraulic Pnsititute, Enginea'ngData Handbook, 1st Ed., 1979, Cleveland, Ohio.
(text continued from page 72) Laminar Flow

When the Reynolds number is below a value of 2000,
Equation 2-25 is valid for calculating the head loss due the flow region is considered laminar. The pipe friction
to va.lves and fittings for all conditions of flows: laminar, factor is defined as:
transition, and turbulent [3]. The K values are a related
function of the pipe system component internal diameter
and the velocity of flow for v2/2g. The values in the stan- f = 64/% (2.17)
dard tables are developed using standard ANSI pipe,
valves, and fittings dimensions for each schedule or class Between R, of 2000 and 4000, the flow is considered
[3]. The M value is for the size/type of pipe, fitting, or unsteady or unstable or transitional where laminar
valve and not for the fluid, regardless of whether it is liq- motion and turbulent mixing flows may alternate ran-
uid or gas/vapor. domly [3]. K values can still be calculated from the