Rubber Hydraulic Hose: Where a Book Can be Judged by Its Cover!

The hose industry is a complex one. There are many professionals who make judgement calls in regard to hydraulic hoses without a thorough understanding of the complexity involved in selecting the correct hose for a particular application. Without the insight of engineering professionals who are familiar with the wear and abrasion of hose covers, or industry experts with equal field experience, this can be a very risky decision. Very few individuals, if any at all, can be experts on every single application’s intimate details, including: its motion, abrasion intensity, number of cycles, or expected life cycle, (aka: duty cycle). The lack of diligence to consult experts on these subjects has become more of an issue today than ever before. It is interesting to ask then, why does this process have so many challenges?

By Blake Justice, National Sales Manager, Fluid Hose

Figure 1. Results explained. The value of each stack is indicative of the amount material that was removed during the testing. Meaning the higher the value the worse the abrasion resistance.

Current Challenges

Challenge #1

Ongoing Equipment Manufactures (OEM):

Automated supply chain systems are growing and will eventually dominate. Now is the time for engineers to make certain the correct hose is plotted in their supply chain. This often conflicts with supply chain’s goal of buying right, if ‘right’ is defined as spending less. The current challenge with this transition is that engineering or field expertise is rarely consulted.

Challenge #2

Maintenance, Repair and, Overhaul (MRO):

The hydraulic hose industry has enjoyed decades of industry experience in the field, a trend that is not likely to be continued by incoming generations. At a tribal knowledge level, the field is where complex questions can be addressed faster than second- or third-level consultations allow; a salesperson speaks to applications engineer who seeks further answers, before returning to answer the upfront questions posed by customers.

This transition to less field experience has taken place during a decade of increase demand, at a time experiencing supply issues, and when newer generations prefer a role in an office atmosphere over a technical field sales position in hydraulics, generally speaking.

If it is agreed that these are realistic assessments of the current industry trends, then it seems logical to predict that:

  • Fewer OEM’s will be selecting, or capturing, the best product for the duty cycle that their equipment will be sold for;
  • There will be less accuracy in after market replacement product suggestions; to get an application up and running and to keep it running for as long as possible (duty cycle of MRO);
  • Those who pay for the product will likely spend more money in replacement hoses. Unless the operator can be intimately certain that the set up of the OEM hose’s intended duty cycle was done accurately, or that the person suggesting an after-market replacement is quite knowledgeable in the hose industry as far as their application goes, it will likely cost more to replace the hose later; and,
  • Automated preventative maintenance software linked to hose tagging may not be as predictable as projected. If it is set up properly, however, it will save costs over time.

At this point it is beneficial to question how one can verify the integrity of the hose selected for the intended application, before data on the hose is exposed.

Sharing Knowledge

As always, it goes back to product knowledge. Although hose wear and abrasion cannot be easily assessed in a systematic way across many applications, sharing knowledge can help those who wish to learn how best to assess the needs of their application. With that said, this article hopes to highlight the importance of choosing an appropriate hose cover for the intended application, drilling down to hitting the target duty cycle.

There are currently many hydraulic hose and fitting brand offerings on the market. In the initial stages of choosing a brand to work with, it is always best to go with one that has innovated their products in a manner that relates to the application in question. It is also beneficial if they have a collaborative culture with their distribution network.

The case study below can be used to illustrate the importance of choosing the appropriate cover.

Case Study

In the case of this study, Fluid Hose set out to verify the effectiveness of the Manuli ROCKMASTER brand of hose in a very aggressive application in the mining industry. The mission was to find a gold mine seeking more value in a flexible hydraulic connection than the typical ‘replace it when it wears out’ approach. Thanks to a collaborative Canadian mine, this mission was accomplished.

The Project

The ‘Jumbo Drilling Machine’ (Image 1) is essentially a tractor with two arms. In this case, it also has hydraulic actuation off the front of it. As the machine drills away at the rock in the underground mine, the rock and other abrasive materials tend to fall on the hydraulic hoses that are constantly in motion as each arm pounds at the rock in an in-and-out motion. The application is a fabulous test for:

  • Pulsation where the hose fitting is crimped to the hose;
  • Constant movement creating a challenge for the hose layering;
  • Hose elongation under dynamic pressure (the hose is purposely tensioned around a roller to facilitate the arms pound inward and back again repeatedly);
  • External abrasion of the cover that tends to ‘tear’ the covers off and expose the reinforcement.

The Results

One set of hoses was installed on one arm of the Drilling Jumbo machine and the competing brand was installed on the second arm of the same machine. Since both arms are used equally it was deemed each brand had equal product placement with regards to wear from movement.

Importance of Hose Covers

First, it is important to understand hydraulic hose covers and how manufacturers refer to their hoses with regards to abrasion resistance. Figure 1 shows the abrasion test results on the various Manuli hose covers. As each abrasion test varies per manufacturer, it is important to note that the type of testing depicted here is specific to the Manuli brand. It is also important to note that there are no standards in place to measure hose abrasion resistance equally across the different brands; most of the time manufacturers do not share ‘how’ they test their abrasion resistance. Typically, they choose to market their covers using words to explain the abrasion resistance of their products.

As there are no current standards for abrasion testing, and manufacturers do not need to divulge the method of testing they use, the term ‘abrasion resistance’ is very subjective and relative to a specific need or application. The tests performed by Manuli are listed below for transparency. In Figure 1, the type of Manuli hose cover is listed along the bottom below the red value. The y-axis represents the amount of material that was removed during the test (abrasion weight loss). Referring to Figure 1, the hose that was field tested is shown to have a ‘Strong’ or ‘SD’ type cover.

Image 1: Jumbo Drilling Machine.

The study in question is still ongoing. At the point of writing this case study, the Manuli ROCKMASTER hose still has not failed. This means the hose is still going strong after 14+ months! By this time the competitive hose brand was replaced three times. Considering the abrasion from the rocks and the excessive elongation from dynamic pressure and tensioning, the Manuli ROCKMASTER hose showed great resistance and strength.

Concluding on Value

This application is a brutal one leaving any mine to realize these hoses will fail and will be replaced from abuse strictly from its intended duty cycle. However, both hoses were the same specification based on the manufacturer’s description of the strength of their hose covers. These results showed a drastic gap in perception. It is this type of study that can truly reveal the value of a product!

Manuli’s commitment to designing and producing industry-leading hydraulic hose and fitting systems will continue. Fluid Hose will continue to collaborate with Manuli and the industry willing to educate and share knowledge along the way.


Blake Justice has had a career that spans 31 years in the Hydraulic and Industrial Hose Industry. He has indepth experience around sales, product management, technical applications and material, manufacturing and importing across Canada.

Previous articleMost Profitable Sectors of the Food Industry for Hoses & Couplings
Next articleHoses for Hydrogen Fueling Stations