Polymer Hose Distribution Catalogue 4402

Technical handbook

Flow capacity nomogram Formel

Flow capacity nomogram

The chart below is provided as an aid in the determination of the correct hose size. Example: at 10 gallons per minute (gal/min), what is the proper hose size within the recommended velocity range for pressure lines? Locate 10 gallons per minute in the left-hand column and 20 feet per second in the right-hand column (the maximum recommended velocity range for pressure lines). Lay a straight line across these two points. The inside diameter shown in the centre column is above -6 so we have to use -8 (1/2"). For suction hose, follow the same procedure except use recommended velocity range for intake lines in the right-hand column.

Flow Q (l/min)

400

Technical handbook

where: Q = flow in gallons per minute (gal/min & l/min) V = velocity in feet per second (f/s & m/s) d = hose inside diameter (mm & dash size)

300

Example Flow Q = 45 l/m

= 

200

l m

∗ 21,2025

45

D = 

Velocity V = 6,1 m/s Konstant K = 21,2025

Q ∗ K V

= 12,5 mm

m s

150

6,1

Inside diameter d mm

dash sizes inch

Velocity

100 90 80 70 60 50

feet/s

m/s

2

-32

50,8

0,6

2

1-1/4 1-1/2

-20 -24

31,8 38,1

3

1

40

1

-16

25,4

Recommended maximum velocity for suction lines

1,2

4

30

3/4

-12

19,1

5

8 7 6

5/8

-10

15,9

2

20

1/2

-8

12,7

15

Recommended maximum velocity for return lines

5/16 3/8

-5 -6

7,9 9,5

10

3

D = sqrt{{Q*K} over {V} } = sqrt{{45 l over m * 21,2025} over {6,1 m over

4

10 9 8 7 6 5

1/4

-4

6,3

15

5 6,1

Recommended maximum velocity for pressure lines

20

3/16

-3

4,8

7 8 9

30 25

4

UK gallons Conversion factor: gal/min x 4,546 = l/min feet/s x 0,3048 = m/s

* Recommended velocities are according to hydraulic fluids of maximum viscosity 315 S.S.U. at 38°C working at roomtemperature within 18° and 68°C.

V