Select the Right Hose

These tools will help you to select the right hose for your application, to ensure your challenge is addressed successfully. Although many metal hoses look the same, there are many critical questions to ask and characteristics to consider in order to optimize the hose for the application.

Link to Chixing

First, let’s introduce you to S.T.A.M.P.E.D. To properly design a metal hose assembly for a particular application, the following design parameters must be determined. To help remember them, they have been arranged to form the acronym “S.T.A.M.P.E.D.”

1. Size – The diameter of the connections in which the assembly will be installed is needed to provide a proper fit. This information is required.
2. Temperature – As the temperature to which the assembly is exposed (internally and externally) increases, the strength of the assembly’s components decreases. If you do not provide this information it will be assumed that the temperatures are 70 deg F.
3. Application – This refers to the configuration in which the assembly is installed. This includes the dimensions into which the assembly must fit as well as the details of any movement that the assembly will experience. This is required since you cannot determine the proper length or proper hose type without it.
4. Media – Identify all chemicals to which the assembly will be exposed, both internally and externally. This is important since you must be sure that the assembly’s components are chemically compatible with the media. If no media is given, it will be assumed that both the media and environment are compatible with all of the available materials for each component.
5. Pressure – Identify the internal pressure to which the assembly will be exposed. Stripwound metal hose, by the nature of its construction, is not pressure tight. However, pressure and media infiltration through the stripwound wall can be minimized by the insertion of one of a variety of packings into the wall during hose manufacturing. If no pressure is given it will be assumed that there is no pressure.
6. End Fittings – Identify the necessary fittings. This is required since fittings for the assembly must be chosen to properly fit the mating connections.
7. Dynamics – Identify the velocity at which the media will flow through the assembly. Extremely high flow or abrasive media can cause premature failure. If no velocity is given, it will be assumed that the velocity is not fast enough to affect the assembly’s performance.

Selecting the proper configuration – whether it’s hose & assembly components or expansion joints – is crucial. Type, size, alloy, length, and other factors must be carefully reviewed. Every application is different, so you must ensure each assembly is designed specifically for your purpose and operating conditions.

Does this sound familiar?

• Your hose is exposed to temperatures below -50°F or above +300°F.
• Your hose’s cover is cracking.
• Your hose is exposed to harsh chemicals.
• You keep replacing the same hose over and over.
• You wish you could use a metal (rigid) tube, but you need the flexibility of a hose.

If this is you, stop replacing the same hose over and over – go for a flexible metal hose!

The Resilience of a Tube – The Flexibility of a Hose

Any hose assembly is only as good as its weakest link; in the case of a metal hose assembly, the weakest link can be the welding process. The methods of seam and butt welding, as well as fitting attachment, utilized in flexible metal hose assemblies yield a consistent, reliable, leak-free connection.

For more information, please visit PTFE Hose.

There are many different types of end connections available for flexible metal hose assemblies:

• Male Pipe Thread (NPT & NPTF)
• Female Pipe Thread
• Male and Female JIC 37° Flare
• Universal Tube Stub
• Female O-ring Face Seal
• Instrumentation Compression
• Flange Fittings

Flexible metal hose assemblies are available in three styles to accommodate the diverse applications of flexible metal hoses. Tube material is available in either 316L or 321 Stainless Steel. Outer jacket (cover) is available in T304 or T316 Stainless Steel.

Metal Hose Features

• Stainless Steel construction results in excellent chemical resistance.
• Metal hoses maintain integrity in high temperature environments - up to °F
• Metal hoses are available in a wide range of sizes – ¼” I.D. up to 6” I.D. Contact us for larger sizes.
• Hydro-formed design yields a uniform wall thickness, promoting even distribution of stress during flexing and reducing concentrated residual stress.
• Metal hoses maintain their shape under full-vacuum.
• Zero permeation means that harsh chemicals will not escape into the environment.
• Seam and butt welding result in leak-free fitting connections.
• Metal hoses are suitable for cryogenic applications (temperatures as low as -380°F).

Select Flexible Metal Hose for Your Application

• Standard (Such as Parker 9A Hose) – Suitable for most applications
• Ultra Flexible (Such as Parker 9M Hose) – Reduced minimum bend radius
• High Pressure (Such as Parker 9H) – Up to psi working pressure

In summary, flexible metal hose assemblies are a true alternative to hard line Steel or Stainless Steel tube assemblies where greater flexibility is needed.  Because flexible metal hose assemblies are stainless steel throughout, they meet the need for chemical and extreme temperature resistance. The corrugated core tube allows flexibility that a hard line cannot. Hose reinforcement matters, be sure to choose the correct hose.

Posted by Roger Winchell