The need for hose replacement is a fairly common occurrence on hydraulic machines. Hydraulic hose fabrication is a big business with plenty of competition and more than a few cowboys running around. So if you own or are responsible for hydraulic equipment, where you source replacement hoses from, and how they’re made, cleaned and stored – prior to installation on your machine, warrants your attention.
The hose fabrication process – or more specifically, the hose cutting process – introduces contamination in the form of metal particles from the hose’s wire reinforcement and the cutting blade itself, and polymer dust from the hose’s outer cover and inner tube.
The amount of contamination which enters the hose during cutting can be reduced by employing techniques such as using a wet cutting blade instead of a dry one, blowing clean air through the hose as it is being cut and/or using a vacuum extraction device. The latter two aren’t very practical when cutting long lengths of hose from a roll or in a mobile hose-van situation.
Therefore, the main focus must be on effectively removing this cutting residue – and any other contamination which might be present in the hose – prior to installation. The most efficient and, therefore, most popular way of doing this is by blowing a foam cleaning projectile through the hose using a special attachment connected to compressed air. If you are not familiar with this equipment, do a search on Google for “hydraulic hose projectile”.
The manufacturers of these cleaning systems claim that hose cleanliness levels as good as ISO 4406 13/10 are achievable. But like most everything else, the results achieved depend on a number of variables, which include using a projectile of the correct diameter for the hose being cleaned, whether the projectile is used dry or wetted with solvent, and the number of shots fired. Generally, the higher the number of shots, the cleaner the hose assembly. Furthermore, if it is a new hose that’s being cleaned, the projectile cleaning should be done before the ends are crimped on.