Pressure Drop Calculations - Basket Strainers

To accurately calculate the pressure loss for filters and strainers in a pipeline, proceed as follows:
  • 1. First calculate pressure loss using Cv factor formula below. (refer product page for Cv Factor)
  • 2. Take the pressure loss figure obtained in (1) and recalculate it using the appropriate correction factor from the following table.
Pressure Loss Calculation Using Cv Factor
Standard Units Metric Units
ΔP = Pressure Drop in psi
  Q = Flow rate gpm (US)
Cv = Flow Coefficient
ΔP = Pressure Drop in kPa
  Q = Flow rate M³/hr
Cv = Flow Coefficient

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

For example, a 1" Model 72 simplex strainer with a perforated basket has a Cv factor of 22.5. In water service with a 30 gpm flow rate, it will have a 1.7 psi pressure drop (30 ÷ 22.5)2 = 1.7.

For mesh-lined baskets and/or fluids with a viscosity greater than water, multiply the pressure drop by the correction factors in the chart “Correction Factors for Mesh-lined Baskets.“

 
Correction Factors for Mesh-lined Baskets
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
30 (water) 0 1.2 1.4 1.6 1.7 2.0 2.5
500 1.6 1.9 2.1 2.4 2.6 3.1 3.6
1,000 1.7 2.2 2.4 2.6 2.8 3.3 3.8
2,000 1.9 2.4 2.7 2.9 3.2 3.8 4.0
3,000 2.0 2.6 2.9 3.2 3.5 4.1 4.3
5,000 2.2 3.0 3.5 4.0 4.5 5.3 6.3
10,000 2.5 3.5 4.2 5.0 6.0 7.1 8.5
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 0.3810 380
20 0.034 0.8636 862

 

Perf Inches Millimeters Microns
1/32" 0.033 0.838 838
3/64" 0.045 1.143 1,143
1/16" 0.070 1.778 1,776
3/32" 0.94 2.387 2,387
1/8" 0.125 3.175 3,175
5/32" 0.150 3.810 3,810
3/16" 0.1875 4.762 4,762
1/4" 0.250 6.350 6,350
3/8" 0.375 9.525 9,525
1/2" 0.500 12.700 12,700