Most of the interlocked hose failures can be attributed to one of three: torque, abrasion, and over-bending.
Metal hose transfers dangerous media like gases and thermal oils. As such, hose failures can lead to a significant danger to those operating the application and the surrounding environment. Interlocked metal hose failures can result in costly fixes, system downtime or worse, injury on the site. Depending upon the application, hose failures can also harm the gear in which the hose is used, bringing about thousands, even millions of dollars lost.
In this article, we will examine the common failures of interlocked hoses and look at how to prevent the same.
Find Solutions for Interlocked Hose Failures
The stainless steel interlock hoses are manufactured by helically winding metal strips over a sizing mandrel. The metal strips already have minor folding which is interlocked together to form an interlock convolution (two profiled lock segments). Through this continuous process, a hose length is formed. The limit of axial elongation and contraction is established when the convolutions are all fully open or closed.
Interlocked hoses are used in medium strain applications (15-20 PSI) and can also be used as an external coat for insulated pipelines. To limit spillage and make the hose pressure-tight, interlock flexible metal hoses can be manufactured with different packing materials. These can be embedded along the length of the hose, offering a protective/conduit casing. The packing may be of copper wire, asbestos chord, glass wool chord etc.
Here are a few causes of Interlocked Hose failure. Knowing these can help you better prepare or take action immediately in the case of an unfortunate event at the work site.
Perhaps the most common cause for failure is using a hose, fitting, or brace in an application that it isn&#;t intended for. Using the wrong interlocked hose for an application can be catastrophic.
Once the spike of the squeezing cuts into the container of the hose, the product being conveyed can escape. This could lead to percolating or rankling of the cover inside, resulting in a failure.
As temperature increases, pressure evaluations decline. Extreme hot or cold temperatures will result in hose staining, breaking, or hardness. It could also lead to the development of friction-based electricity if the hose wire has not been grounded as required.
Kinks, squashed segments, and harm to the cover will ultimately separate the support and lead to a hose failure.
Kinking, pounding or constraining a hose to twist past its base curve span (estimated from within the edge of the hose, not the centerline) can lead to failure. This is generally seen on high-strain hoses or vacuum hoses.
Failure from a defective hose will normally happen in the initial stages. It can cause pinholes, blow-outs, or cylinder and cover division. Inappropriately installed or chosen clamps can bring about coupling-catapulting from the end of the hose.
This usually brings about staining, expansion, springiness, or the breakdown of the hose cadaver. Unsuitable liquid or harsh climate can also lead to the wear of the hose tube.
The hose isn&#;t a &#;pipe&#;; it is an adaptable part that can last for a long time. Shelf or service life will go from 1 to 20+ years, depending upon its structure, application, and climate. However, checking the hose at regular intervals is important, as despite its durability, some hoses can fail due to old age.
Too short hose length doesn&#;t permit the hose to lengthen or contract as per the changes in strain or temperature. This can put extreme stress on the hose fittings, leading to damage or failure.
Find Solutions for Interlocked Hose Failures
As safety insurance and to safeguard an organisation&#;s machinery, we suggest regular examination of hose assemblies. Everyone working around hose assemblies should know the most widely recognised signs of a hose failure. Assuming any of the following signs are noticed, replacement hoses should be considered, before the failure occurs.
Some of these things can be fixed before replacement hoses are required. In the case of loose or damaged hose guards or covers, change the guards or covers first. However, a cautious inspection of the hose and interlace underneath should be completed before opting for replacements.
A loose fitting might be fixed, and new labels might be made if information can be acquired from the manufacturer. If hoses are rubbing against each other, use hosebuns to make space between the hoses, the ground or close to the machinery.
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At Aeroflex, we offer a series of interlock metal hoses. Depending on the application, you can choose:
Application: Used as a liner in metal hoses, exhaust flue gases and anti-kink segment for metal hoses.
Application: Used for armouring and protection
Application: Used in hose liner and exhaust flue gases
Hydraulic hose fittings are essential components in countless stationary and mobile machines. The parts are critical links in fluid-power systems, designed to ensure safe and reliable operations and prevent equipment shutdowns, catastrophic failures and danger to nearby personnel.
And in the hydraulics world, there are generally two types of hose fittings &#; permanent and reusable or field-attachable. Permanent crimp fittings mechanically interlock to hose by means of a crimping or swaging machine and are designed to form a durable, leak-proof connection. A crimp fitting cannot be removed and reinstalled.
Reusable fittings, as the name implies, are designed to be used multiple times. These hydraulic fittings can be disassembled and reassembled so that modifications or repairs can be made to the hydraulic system without replacing the entire hose assembly.
Given that these fittings may be considered for reuse, they can make for an economical choice in applications where field repairs are necessary or frequent changes are anticipated. And the relatively simple design facilitates quick disassembly and reinstallation, saving both time and labor costs.
However, one major drawback is their general unsuitability for high-pressure applications. The absence of a mechanical lock typical in crimp fittings reduces their overall pressure tolerance. Reusable fittings tend to be limited to low-to-medium pressure applications up to around 3,000 psi.
Therefore, these fitting are generally preferred when adaptability and flexibility are more critical than high-pressure performance. These include prototyping hydraulic systems that are still being tested and require frequent modifications. In high-speed industrial production and assembly operations, downtime can be costly. Where pressure requirements are moderate field-attachable fittings offer the ability to make quick or emergency repairs right at a machine.
In less critical mobile systems like agricultural sprayers or other low-pressure hydraulic machinery, the fitting&#;s on-site repair ability is also an advantage, especially in remote or rural areas where new components or crimpers may not be readily available.
But are field-attachable fittings truly reusable?
Many experts agree that, in a perfect world, it&#;s always preferred to opt for new fittings when a user reassembles the connections. But, thanks to improvements over the years in terms of better materials, designs and manufacturing processes, hydraulic fittings that are in good working order can sometimes be reused.
According to John Joyce of Brennan Industries, several factors come into play when considering whether hydraulic fittings can be reused. The most crucial is the condition of the fitting. A fitting may appear in good condition, but it must be inspected before reuse.
Visually check for anything sketchy. Look for any signs of concern, such as:
&#; Wear or damage on the fitting, such as cracks or deformations.
&#; Nicks or scratches to any sealing surface.
&#; Corrosion, rust, or material deterioration that can weaken the metal and compromise the fitting&#;s integrity.
&#; Physical abuse such as dents or any distortion to the shape of the fitting.
&#; Fitting nose collapse.
If there are any signs of damage, the fitting should be replaced to ensure the safety and reliability of the hydraulic system. In addition, it&#;s best to replace O-rings or seals regardless of how they may look.
And many industry representatives do not recommend reassembling tapered thread pipe fittings and JIC 37° flare fittings. Pipe fitting connections rely on deformation of the sealing threads to obtain a seal, and they can wear out or deform with repeated assembly and disassembly.
JIC 37° flare fittings use a cone and flare connection to seal. The connection causes a slight deformation of the metal surfaces to obtain a seal. Excessive torque can permanently distort the interfaces and lead to an insufficient seal.
Again, best practice is always to replace a fitting with new parts. But if the fitting is found to be in good condition, and the user opts for reuse, here a few additional tips. First, plan to reassemble the assembly with new hose &#; not the existing worn or damaged hose. Confirm that the hose and fitting are compatible in terms of material, size, and pressure ratings.
Before reuse the fittings must be thoroughly cleaned, as any dirt or debris could potentially enter the hydraulic system and cause damage. Ensure you are following the proper procedures for reassembly. Never mix fittings from different manufacturers or use &#;similar looking&#; parts, and follow the guidelines provided by the equipment manufacturer.
After reassembly, look for any signs of improper installation, such as misalignment or visible gaps. And finally, test the new connection to ensure the seal is tight. If there are any leaks, replace the assembly immediately.
In the end, be critical and always err on the side of caution. If you have any doubts &#; if you question the viability of the fitting in any way &#; it is always best to replace the fitting to avoid potential risks.
If you want to learn more, please visit our website interlock hose fittings manufacturer.