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Technical Articles
October 8, 2018

Patented Fail-Dry® Allows Valves with Seal Failure to Continue Operating until Maintenance can be Conveniently Scheduled











Valves remain sealed and fully operational, even after primary seal failure


Under normal conditions, Plast-O-Matic elastomers last over a million cycles; in some cases many millions of cycles. But in the event of excessive pressure or other unexpected conditions, the patented Fail-Dry® safety feature provides advance warning…and enables you to prevent a complete valve failure before it occurs.

The Plast-O-Matic Fail-Dry is the unique concept of having a vented chamber separating two sealed sections of a valve. One of these sections is the liquid media, the other is the operational chamber (the operational chamber typically contains a spring in a pressure valve, a spring and/or air chamber in a shutoff valve, and a core tube in a solenoid valve, for example). The primary seal — in contact with the liquid media and subject to pressure — will naturally break down before the secondary seal.

When the primary seal begins to fail, it releases trace amounts of liquid into the chamber and through the Fail-Dry vent. The secondary seal still isolates the operational chamber, so that it remains dry…Fail-Dry!

Fail-Dry Valves remain fully operational

…and so does your system. Since the failure can be diagnosed early, valve repair can be performed before a catastrophic failure (such as a seized valve) can occur. Early detection by the Fail-Dry reduces the number of parts to be replaced.

Repair costs are lower

All valves require maintenance. Although some manufacturers offer a slightly lower initial price, the Fail-Dry prevents the operational chamber from being attacked, so that only the elastomers need to be replaced. More importantly, the Fail-Dry is your best protection against dangerous valve related spills, injuries, and costly downtime.

The Fail-Dry illustrated above is a cutaway photo of Series RVDM Relief Valve. Series EASM- Solenoid Valves have a similar looking Fail-Dry. Other valves employ the vent in different ways; for example, sometimes it is a vented chamber between u-cup seals. In each case, the principle and performance are the same.

If you have any questions about the Fail-Dry feature, or need to know which Plast-O-Matic products specifically carry it, please call our Technical Department at (973) 256-3000 for personal assistance.