Technical Data

Pressure Drop Calculations

To accurately calculate the pressure loss for filters and strainers in a pipeline, proceed as follows:

 

  • First calculate pressure loss using Cv factor formula at right
  • Take the pressure loss figure obtained in (1) and recalculate it using the appropriate correction factor from the following tables.


Pressure Loss Calculation Using Cv Factor

Filtration Strainers - Pressure Loss Formula

 

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