Seals, Scrapers and Rings
The proper seals prevent leakage in many applications. In cylinders, they prevent internal and external leakage within fluid paths. In valves and prevent both external and internal leakage. Applied to the base of valves, they prevent external leakage from occurring. Internally, they secure flow and prevent leakage from occurring between the internal body of the valve and its bushing and/or sleeve and spool assemblies. Most seals are made of media that is produced to withstand the specific fluid that is used on a particular system. Average systems with standard fluids and running temperatures have cylinders and valves that use Alpha brown o-ring seals though systems that use fyrquel fluid, which run at higher temperatures, use Alpha black o-ring (Buna-N) seals. Each type of seal meets the demand of the particular system on which it is applied. Replacement of worn seals is imperative to prevent leakages within the system and potential system failure.
Scrapers serve as an external contamination remover for the shaft and operation of the cylinder of the control pac. Unlike seals, they allow for some flow to pass the cylinder head or rod gland allowing lubrication to the surface being scraped. Scrapers are made of a standard high tinseled steel that withstands the pressure and heat of the fluid that flows over them. Replacement of scrapers is necessary upon the discovery of contamination such as heavy varnish buildup around them which can cause disruption of fluid flow hindering performance. Neglecting to replace them after enough build up can cause the head to lock within the cylinder and lead to system failures.
Rings are found in many places throughout components. They are sometimes visible and provide backing support to assure proper sealing at high pressures. Improper backup rings can lead to leakages and failure. These rings that act as guards and protectors of seals are made of standard brass, and other media as necessary and unlike steel, absorbs heat and slowly returns it to the fluid. Rings must be inspected for wear and varnish and replaced if beyond refurbishment.
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