Hose + Coupling World December 2021 Sample - Page 35

TECHNICAL ARTICLE
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 .
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 on the previous page 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 .
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
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