If no special options or accessories are needed, there are four basic components to a corrugated metal hose: The tube (or hose itself), the braid, the braid collars, and the fittings. There may be times where an unbraided hose will work, but most applications require an assembly containing these four components. Let’s look at each of these components and their function as part of the total assembly, and how they all work together to provide value.
Fittings
Corrugated metal hose assemblies are able to incorporate virtually any fitting that is able to be welded to the hose ends. Because of this, it is critical that the end fittings selected are appropriate for the intended application. Make sure the fittings are the right size, alloy, and pressure (designated by pipe schedule, tube gauge, pressure class, etc.) for the application, including any piping standards or specifications that must be met.
Braid Collars
Braid collars are used to join the inner corrugated hose and the braid together during the cap welding process, where a TIG weld joins the hose, braid, and braid collar into the cap weld bead. A good cap weld becomes the base for the subsequent attachment weld. Additionally, the braid collar serves to isolate the last few corrugations from movement, as their cycle life may be compromised by the heat required to properly weld fittings to the hose. It is critical that the braid collars are sized properly in order to facilitate welding and to protect the last few corrugations from movement.
Braid
To give corrugated hose the ability to withstand high pressures, braid wires made from stainless steel or some other alloy are braided onto the hose. There are many variables that can affect how well the braid works, including the wire diameter, the number of wires per carrier (bobbin), and the number of carriers. Additionally, the performance of the hose may be enhanced by using multiple braid layers or braided braid. Hose Master knows that the proper braid design has a significant effect on both the working pressure and the cycle life of the hose. That is why they carefully design each braid package to ensure a high-percentage braid coverage, and we apply the braid directly onto our hose in all sizes to ensure that the braid fits tightly, protecting the hose from potential deformation and ensuring maximum cycle life.
Tube
The tube is the actual corrugated hose, which contains the media being conveyed and provides flexibility as required by the application. Hose Master employs various corrugating processes in order to produce the most flexible products in the industry, and our proprietary forming technology offers the best product for the majority of industrial applications.
There are a lot of variations to the above components and it requires a lot of know-how to produce a superior product. Now, let’s talk about how we define value when designing our products.
Attributes That Define Value of Corrugated Metal Hose
There are 4 primary attributes (as well as a variety of secondary features) to be considered when selecting a metal hose.
- Pressure Rating (MAWP)
- Flexibility / Cycle-Life (MDBR)
- Corrosion Resistance
- Cost
Corrosion resistance is basically a matter of selecting the right alloy (although there are other factors we must also consider). Our challenge as a manufacturer is to develop the appropriate process to make a product that best satisfies the remaining three attributes of pressure, flexibility, and cost.
Pressure Rating is the term used to express the ability of the hose to handle internal pressure. The pressure rating of a hose is determined by conducting various pressure tests in Hose Master's Product Analysis Lab. The pressure rating for a hose is expressed as the Maximum Working Pressure in their catalog, and must be adjusted as required in order to compensate for temperature fluctuations or in-service dynamics such as pressure spikes or water hammer.
Flexibility is a term used to indicate that a hose must be able to bend while in service. However, flexibility may mean different things to different people. Some people need a hose that can be bent into a tight radius, while others want a hose that has a high cycle life. Still others want a hose that is pliable, and will easily bend without exerting high spring forces on the equipment to which the hose is attached. In most applications, Hose Master’s proprietary forming process is the best method to form a hose that provides all three attributes. For corrugated hoses, flexibility is expressed by the Minimum Dynamic Bend Radius (MDBR), which is derived through cycle testing in Hose Master's lab.
Cost is the balancing factor in all purchasing decisions. Making a buying decision based solely on cost assumes that all products are identical except for their price, which is absolutely false. While there may be less costly metal hoses available in the marketplace today, Hose Master's value (quality and service) exceeds the cost of their product.
Gallagher Fluid Seals is the northeast and mid-Atlantic distributor of Hose Master products. From corrugated metal hose, to stripwound metal hose, to metal expansion joints, Hose Master is a premier fabricator of metal products with 90+ ASME IX Certified welders on staff. Interested in learning more? Contact us today to find out more ways Gallagher and Hose Master can assist you in providing the best metal hose solutions with the greatest value.