Selecting the ideal hydraulic or industrial hose size is critical in delivering the intended performance. In the hose industry, a nomographic chart helps users choose the appropriate hose size based on system fluid volumetric flow rate and fluid velocity. Here, we will discuss sizing for hoses used in the industrial market and guide you through sizing with a nomographic chart.
Size Specifications of Industrial & Hydraulic Hoses
Industrial/Hydraulic hose sizing is specified by inner diameter. Outer diameter (OD) is a measurement of the entire diameter of the hose cross-section, including the diameter of the tube and any covers or reinforcement. The outer diameter takes the hose wall thickness into account, unlike inner diameter (ID) measurements, which only describe the diameter of the inside of the hose. The OD is a critical characteristic to identify the right size fittings and other components for industrial hoses.
Inner diameter is the measurement of the space inside the flow cross-section, and it will affect the flow velocity of the media traveling through the hose. An oversized ID can deliver slower flow, while an undersized ID can result in tube damage, heating of the fluid and the hose, pressure drops, and system damage due to tube failure and premature failure of the hose itself.
Hydraulic Hose Sizing With Nomographic Chart
What Is a Nomographic Chart?
A nomographic chart is a visual tool that allows users to choose the ideal hose size based on system fluid volumetric flow rate and fluid velocity. Users also need to know whether the hose will be used in suction or discharge. Inherent in the design of a standard nomogram is a series of formulas and calculations that users would otherwise need to do without the chart. One of these formulas is the following:
Area (in.2) = 0.321 x gallons per minute (GPM) / Velocity (feet per second)
How to Use a Nomographic Chart
The left-hand column represents flow in gallons per minute, the middle column is the inside diameter of the hose, and the right-hand column represents suction or discharge velocity in feet per second. Once you understand each column, follow these steps:
- Identify the volumetric flow rate required for your system and whether the hose is in suction or discharge.
- Lay a ruler across the chart connecting the flow rate number to the recommended velocity range for suction or discharge.
- Find the intersection points on the middle column to determine what IDs of the hose are recommended within the velocity flow range.
For example, to determine the minimum ID of a hydraulic pressure hose required to transport fluid at a rate of 20 GPM, draw a straight line from 20 GPM on the left side of the chart to the maximum recommended velocity on the right side, which is 15 feet per second. The line should intersect the middle vertical column, identifying a hose with an ID of ¾ in. If the velocity is higher than the recommended range, it could cause issues with the hose, like erosion or degradation of the tube.
On hoses used for return or suction to the intake of a pump, the maximum recommended velocity should not exceed 4 feet per second to avoid pump cavitation and damage to the hose, which leads to system failure.
The above recommendations are for fluids at operating temperatures between 65 °F (18.3 °C) and 155 °F (68.3 °C), and a maximum viscosity of 315 S.S.U. at 100 °F (37.8 °C).
Contact Jason Industrial for Hydraulic & Industrial Hoses
Selecting the right hose for your application requires identifying the appropriate ID, OD, and length. Jason Industrial has been a leader in supplying industrial hoses and power transmission belts since 1958. We have distribution centers throughout North and South America to deliver fast solutions. We also offer couplings, fittings, and accessories to deliver a complete solution for your project. Contact us or request a quote to speak with a specialist about our industrial hoses for your application.