HOW TO DETERMINE CORRECT ASSEMBLY LENGTH
Anyone working in the hydraulics industry knows the importance of reducing contamination. Particles, dirt, debris, and even water entering a system can quickly cause a disaster, leading to system failures and potentially destroying a component or machine. That is why keeping these contaminants out is essential.
To ensure that the hydraulic fluid remains free of contaminants, it is essential to clean all new hoses before installation. If contaminants remain in a hose after it has been sent to a customer or after it has been cut and crimped, those rubber and dirt particles will easily end up in the reservoir and flow throughout the system.
Three common methods are used to remove contaminants from the inner tube of a hydraulic hose: high-pressure air, fluid flushing, and projectiles.
Air: High-pressure air can be blown through a hydraulic hose or assembly, provided it is clean and dry. This works best with shorter, smaller hoses, as the longer the hose, the more likely particles are to get trapped inside the assembly. However, this method is not always effective, as the air can often be hot and dirty.
Fluid cleaning: Provided the fluid is clean and compatible with the inner tube of the hose assembly, you can clean an assembly with high-pressure fluids to create an agitating flow to remove contaminants from the inner tube wall. However, to ensure that the fluid is clean on its own, you must use filtration to ensure that the fluid is free of contaminants. Before you can install the hose, you must ensure that the inside of the hose is dry.
Projectiles: Perhaps one of the most effective methods is by using foam projectiles that are shot through a hose assembly using dry compressed air or another clean, inert gas. Special hand-held or table-top launchers should be used to ensure that the projectile travels completely through the tube and does not remain inside the hose. The projectiles should be approximately 20 to 30% larger than the inside diameter of the hose tube, as they compress against the wall of the hose assembly to “grab” dirt and debris.
As the foam projectile travels rapidly through the assembly, it picks up dust, debris, and particles, giving the user a visual indication of how many contaminants it has removed. It is recommended to use these foam projectiles from both ends of the hose assembly, and to make two or three passes until the projectile comes out clean.
These projectiles should never be inserted directly into the inside diameter of the hose by hand. This reckless method of insertion will not allow the projectile to enter the hose tube cleanly and may transfer additional contaminants to the inside of the hose. The projectile may become trapped in the wire reinforcement, and you also run the risk of cutting your fingers. Instead, insert the nozzle into the hose tube, which will create a tight seal. Press the trigger, and the projectile will enter and exit the hose cleanly. Remove the nozzle from the inside diameter of the hose and clean any loose contaminants from the outside diameter of the nozzles. Rotate the hose 180 degrees and repeat the cleaning process. The hose tube is now clean and free of unwanted contamination.
Keeping components clean
It is also necessary to clean the hose components before inserting them. It is vitally important to keep the hose components clean before inserting them. If they are delivered in a sealed bag or box, it is recommended to leave them in the bag until they are ready for use or in the box with the lid on. Often, users open the bag and throw the fittings into a plastic or cardboard container. This simply allows contamination from the air to easily enter inside and onto the fittings. Once the fittings are cleanly inserted into the assembly, the ends should be capped to ensure that they remain free of contaminants.