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Technical Data

Pressure Drop Calculations

  

Pressure Loss Calculation Using Cv Factor
To accurately calculate the pressure loss for filters and strainers in a pipeline, proceed as follows:   Pressure Loss Calculation Using Cv Factor
bulletFirst calculate pressure loss using Cv factor formula at right
bulletTake the pressure loss figure obtained in (1) and recalculate it using the appropriate correction factor from the following tables.

 

   The pressure loss across a strainer or filter can be calculated using the system's flow rate and the Cv factor for that strainer or filter.

For example, a 1 " strainer with a Cv factor of 8 will have a 4 psi pressure loss in a system with a 16 gpm flow rate: (16 ÷ 8) 2 = 4.
Correction Factors for Mesh-Lined Basket
Water Only
Multiply the pressure drop for perforated baskets by the following.
Basket Mesh Correction Factor
40 Mesh 1.2
60 Mesh 1.4
80 Mesh 1.6
100 Mesh 1.7
200 Mesh 2.0
325 Mesh 2.5
 

 

Fluids Other Than Water
First-Multiply the pressure drop for water shown in charts by the specific gravity of the liquid. Second-Multiply the corrected pressure drop figure by the following correction factors for more viscous liquids. (Water has a viscosity of 30 SSU.)
Viscosity
(SSU)		 Unlined
Perforated
Basket		 40 Mesh
Lined
Basket		 60 Mesh
Lined
Basket		 80 Mesh
Lined
Basket		 100 Mesh
Lined
Basket		 200 Mesh
Lined
Basket		 325 Mesh
Lined
Basket
500 1.6 1.9 2.1 2.4 2.6 3.1 3.6
1000 1.7 2.2 2.4 2.6 2.8 3.3 3.8
2000 1.9 2.4 2.7 2.9 3.2 3.8 4.0
3000 2.0 2.6 2.9 3.2 3.5 4.1 4.3
5000 2.2 3.0 3.5 4.0 4.5 5.3 6.3
10000 2.5 3.5 4.2 5.0 6.0 7.1 8.5
             

 

Strainer Basket Opening Equivalents
         
Mesh Inches Millimeters Microns
  400 0.0015 0.0381 38  
  300 0.0018 0.0457 45  
  250 0.0024 0.0609 60  
  200 0.0027 0.0686 68  
  150 0.0041 0.1041 104  
  100 0.0065 0.1651 165  
  80 0.007 0.1778 177  
  60 0.009 0.2286 228  
  40 0.015 0.380 380  
  20 0.034 0.8636 862  
         
         
Perf Inches Millimeters Microns
  1/32 0.033 0.838 838  
  3/64 0.045 1.143 1143  
  1/16 0.070 1.778 1776  
  3/32 0.094 2.387 2387  
  1/8 0.125 3.175 3175  
  5/32 0.150 3.810 3810  
  3/16 0.1875 4.762 4762  
  1/4 0.250 6.350 6350  
  3/8 0.375 9.525 9525  
  1/2 0.500 12.700 12700  
         
 
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Last modified: April 17, 2007