At Ezy-Fit Hydraulics, we receive many queries regarding the seals used in our range of cylinders, and the reason for their use. so we have put together this fact sheet hoping to address some of the many issues we encounter.
In our non-phasing Agricultural cylinders (and many of our other designs), we use a two piece steel piston fitted with a Double Acting Hallite Type 58 (or equivalent) seal which consists of a rubber centre section bonded to rubberised fabric and 2 polyacetal wear rings.
This low friction seal has the advantage of eliminating metal to metal contact due to the wear rings being in constant contact with the cylinder wall. Furthermore, the rubberised fabric absorbs oil to reduce friction under high pressures.
As the cylinder pressure increases, the rubber centre section energises the rubberised fabric, which is in turn pressed against the housing increasing the surface area of the seal. This type of seal has higher duty sealing characteristics than ‘T’ seals, which are commonly used by other cylinder manufacturers.
The Hallite Type 58 seal also has a maximum speed rating of 1.5 feet per second @ 3900 PSI, a speed quite sufficient in the vast majority of agricultural equipment circumstances.
In our range of Agricultural Phasing cylinders, we use a "Slipper Seal", the manufacturer of which varies from cylinder to cylinder. Slipper seals have the advantage of being an extremely low friction/high pressure seal with the ability to "slip" over re-phasing port apertures without sustaining any damage whatsoever.
The gland seals consist of a Hallite or equivalent rod wiper, an ‘O’ ring and back up between the gland and barrel, and a Hallite Type 605 (or equivalent) rod seal.
This is a tried and tested rod seal which has good low friction characteristics and is flexible enough to take up large wear discrepancies in the rod. This means the seal has a long life and as the twin lips of the seal are energised by oil pressure, the higher the pressure, the better the sealing (up to approx. 6000 PSI).
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Ezy-Fit Hydraulics is a manufacturing and marketing company supplying a full range of hydraulic cylinders to government, semi government authorities and private enterprises Australia wide.