Volume Balancing the Mix Manifold
3A0590R 25
Use Table 2 and the examples provided to approximate
how much pressure drop you can expect for every 50 ft
(15.2 m) of hose at 1 gpm flow in that particular hose for
a 1000 cps viscosity material. Adjust for your
applications flow rate and viscosity.
Table 2: Hose Selection by Pressure Drop
Hose ID
(in.)
Pressure drop per 50 ft
section per 1000 cps at 1
gal/min.
(psi)
Pressure Drop per 15.24
meter section per 1000
cps at 1 liter/min.
(Bar)
1/8 55910 1018
3/16 11044 201
1/4 3494 64
3/8 690 13
1/2 218 4
5/8 89 1.62
3/4 43 0.78
Reference Formula
Pressure drop = 0.0273 QVL/D
4
Key:
Q = Vis poise (centipoise/100)
V= Gallons per minute
L= Length (ft)
D=Inside diameter (in.)
Typical flow rates are usually 0.4-0.8 gpm (1.5-3
l/mn) per gun depending on tip size and viscosity.
Example 1: Wha
t is the pressure loss of a 2000 cps
material through 150 ft of 3/8 in. ID hose at 0.75 gpm?
690 psi (from chart) x 2 (viscosity factor 2 x 1000 cps) x
3
(3 x 50 ft hoses) x 0.75 (% of gpm) = 3105 psi loss
That is a lot of pressure loss before the spray gun. Try a
1/
2 in. hose. See Example 2.
Example 2: Wha
t is the pressure loss of a 2000 cps
material through 150 ft of 1/2 in. ID hose at 0.75 gpm?
218 psi (from chart) x 2 (viscosity factor 2 x 1000 cps) x
3 (
3 x 50 ft hoses) x 0.75 (% of gpm) = 981 psi loss
Avoid under sizing the high volume side. Pressure drop
during flow
conditions will increase momentary hose
induced ratio errors. See Table 2.
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