Hydraulic Hose Sizing

Hose Sizing Guidelines

The size of the suction hose for the power cube, it is calculated from the fluid velocity in the hose. The general values used are:

Pressure: 20 ft/sec

Return: 15 ft/sec

Suction: 5 ft/sec

The formula for calculating the hose size is as follows:

V = Q / (3.117 * pi/4 * D ^ 2)

or

D = (Q / (3.117 * pi/4 * V) ) ^ 1/2

Where:

V is fluid velocity in ft/sec

Q is fluid volume in gallons/min

D is hose inside diameter in inches

Supply Hose

V = 20 ft/sec and Q is shown for 13, 16, and 28.5 GPM:

D = (13 GPM / (3.117 * pi/4 * 20 ft/sec) ) ^ 1/2 = 0.515 in

D = (16 GPM / (3.117 * pi/4 * 20 ft/sec) ) ^ 1/2 = 0.572 in

D = (28.5 GPM / (3.117 * pi/4 * 20 ft/sec) ) ^ 1/2 = 0.762 in

Return (Pressure) Hose

V = 20 ft/sec and Q is shown for 13, 16, and 28.5 GPM:

D = (13 GPM / (3.117 * pi/4 * 15 ft/sec) ) ^ 1/2 = 0.595 in

D = (16 GPM / (3.117 * pi/4 * 15 ft/sec) ) ^ 1/2 = 0.660 in

D = (28.5 GPM / (3.117 * pi/4 * 15 ft/sec) ) ^ 1/2 = 0.880 in

Suction Hose

V = 5 ft / sec and the Q is shown for 13, 16 and 28.5 GPM:

D = (13 GPM / (3.117 * pi/4 * 5 ft/sec) ) ^ 1/2 = 1.03 in

D = (16 GPM / (3.117 * pi/4 * 5 ft/sec) ) ^ 1/2 = 1.14 in

D = (28.5 GPM / (3.117 * pi/4 * 5 ft/sec) ) ^ 1/2 = 1.52 in

Note: The sizing guidelines say to always round up.

Horsepower to Flow

Horsepower = Pressure × Flow / 1714, or:

HP = PQ / 1714

For our 28 HP Power Cube delivering 3000 PSI, we calculate the flow as follows:

28 = (3000 * Q) / 1714

Therefore, Q = (28 * 1714) / 3000 = 15.997 GPM

For the upcoming 50 HP Power Cube delivering 3000 PSI, we calculate the flow as follows:

50 = (3000 * Q) / 1714

Therefore, Q = (50 * 1714) / 3000 = 28.5 GPM

Pump Displacement (Cubic Inch Per Revolution, or CIPR)

CIPR = Flow Rate (in GPM) × 231 x Pump Efficiency / Pump RPM

   -or-

CIPR = GPM × 231 * PE / RPM

The 28 hp Briggs & Stratton engine HP is rated at 3600 RPM. With 97% pump efficiency, the pump size is calculated as follows:

CIPR = 16 × 231 * 0.97 / 3600 = 0.996 CIPR

The 50 hp Briggs & Stratton engine HP is rated at 3000 RPM. With 97% pump efficiency, the pump size is calculated as follows:

CIPR = 28.5 × 231 * 0.97 / 3000 = 2.12 CIPR