Edmonton Valve & Fitting Blog

Weekly posts for northern and central Alberta engineers, plant operators, and buyers.

Flow Capacity: What Happens Inside a Hose or Tube

by Luke Wurban, on Fri, Nov 22, 2019 @ 11:11 AM

There are more factors at play than you might think - trust our fluid system experts to help guide you through it


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Learn the roles of fluid viscosity, temperature, pressure and distance

Flow capacity — the amount of fluid that can flow through a hose or tube — isn't just a matter of how large the diameter is. Flow capacity is really a matter or pressure drop. And pressure drop is influenced by four key factors.

Let's start with the fluid itself. How viscous is it? The more viscous, the slower the flow (and vice versa).

Next consider pressure and temperature. Some fluids flow differently under pressure and at different temperatures. 

Third is the inside surface of the tube or hose. A smooth inner core will mean a smoother flow, while a convoluted core will create turbulence. 

Finally, take into account the distance involved in the application. The longer the distance, the more resistance will build up between the fluid and the interior of the tube or hose, which will create additional pressure drop.  

We have produced a short Tech Clip video laying out these factors. We also have a book that spells out all the answers in detail: The Swagelok Tube Fitters Manual. Whether you need some quick insight, detailed instruction, or something in between, Edmonton Valve & Fitting is the place to look for answers. Give us a call at 780-437-0640, or message us through the link below.

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