Spray Pressure Information

Flow Rate

Nozzle flow rate varies with spraying pressure. In general, the relationship between GPM and pressure is as follows:

 GPM1

=

√PSI1 

OR 

 l/min1

√bar1   

 GPM2

√PSI

 l/min2

√bar2   


This equation is explained by the illustration below. Simply stated, in order to double the flow through a nozzle, the pressure must be increased four times.

Higher pressure not only increases the flow rate through a nozzle, but it also influences the droplet size and the rate of orifice wear. As pressure is increased, the droplet size decreases and the rate of orifice wear increases.

The values given in the tabulation sections of our Catalog 50 indicate the most commonly used pressure ranges for the associated spray tips. When information on the performance of spray tips outside of the pressure range given in our catalog is required, contact your local TeeJet representative.

  Pressure_1 Pressure_2



Spray Angle and Coverage

Depending on the nozzle type and size, the operating pressure can have a significant effect on spray angle and quality of spray distribution. As shown here for an 11002 flat spray tip, lowering the pressure results in a smaller spray angle and a significant reduction in spray coverage.

Tabulations for spray tips in our Catalog 50 are based on spraying water. Generally, liquids more viscous than water produce relatively smaller spray angles, while liquids with surface tensions lower than water will produce wider spray angles. In situations where the uniformity of spray distribution is important, be careful to operate your spray tips within the proper pressure range.

Note: Suggested minimum spray heights for broadcast spraying are based upon nozzles spraying water at the rated spray angle.


Pressure Drop Through Sprayer Components

Component
Number

Typical Pressure Drop (psi) at Various Flow Rates (gpm)

3
gpm

5
gpm

7
gpm

8
gpm

9
gpm

10
gpm

15
gpm

18
gpm

32
gpm

  AA2 GunJet®

2.0

5.3

10.0

 

16.0

 

 

 

 

  AA18 GunJet

5.0

13.0

25.0

 

40.0

 

 

 

 

  AA30L GunJet

 

14.0

 

 

 

 

 

 

 

  AA43 GunJet

 

1.0

2.0

 

 

 

 

 

 

  AA143 GunJet

 

0.9

1.7

 

 

3.5

7.9

 

 

  AA6B Valve

 

0.5

1.2

1.7

2.2

2.9

7.8

12.2

 

  AA17 Valve

 

1.5

2.5

3.5

4.0

5.0

11.5

16.0

 

  AA144A Valve

 

1.5

2.5

3.5

4.0

5.0

11.5

16.0

 

  AA1441-1-3 Valve

 

 

 

5.0

 

 

 

 

 

  AA145 Valve

 

 

 

 

 

 

 

5.0

 

  344BEC-24-C Valve

 

 

 

 

 

 

 

 

5.0


Pressure Drop Through Various Hose Sizes

Flow
in gpm

Pressure Drop in psi (10 feet length without couplings)

1/4" I.D

3/8" I.D.

1/2" I.D.

3/4" I.D.

1" I.D.

0.5

1.4

.2

 

 

 

1.0

 

.7

 

 

 

1.5

 

1.4

.4

 

 

2.0

 

2.4

.6

 

 

2.5

 

3.4

.9

 

 

3.0

 

 

1.2

 

 

4.0

 

 

2.0

 

 

5.0

 

 

2.9

.4

 

6.0

 

 

4.0

.6

 

8.0

 

 

 

.9

.3

10.0

 

 

 

1.4

.4


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