Graco 3A059OG important safety instructions Cps at 1 liter/min, Psi Bar, Reference Formula

Volume Balancing the Mix Manifold

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 applica- tions flow rate and viscosity.

NOTE: Typical flow rates are usually 0.4-0.8 gpm (1.5-3 l/mn) per gun depending on tip size and vis- cosity.

Table 2: Hose Selection by Pressure Drop

	Pressure drop per 50 ft	Pressure Drop per 15.24
	section per 1000 cps at 1	meter section per 1000
Hose ID	gal/min.	cps at 1 liter/min.
(in.)	(psi)	(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/D4

Key:

Q = Vis poise (centipoise/100) V= Gallons per minute

L= Length (ft) D=Inside diameter (in.)

#1 Example: What 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. Let’s try 1/2 in. hose. See example #2.

#2 Example: What 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

NOTE: Avoid under sizing the high volume side. Pressure drop during flow conditions will increase momentary hose induced ratio errors. See Table 2.

16 3A0590G