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:

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.

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

EITO & THAI CME CO.,LTD.
152 Soi Sukhumvit 33 Sukhumvit Rd.,North Klongton,Wattana Bangkok 10110 Thailand
TEL : 02-2041012-3 , 02-2041066-7 FAX: 02-2041014
E-MAIL: eitothai@eitothaicme.com.com
WEBSITE : www.eitothaicme.com