Valves play an important role when it comes to process safety: Unauthorized access or accidental operation can quickly lead to catastrophic results. However, both these scenarios are easily prevented - with tamper–proof valve heads.
AS-Schneider provides a range of Anti-Tamper Valve Head Units to allow plant operators to reliably protect their valves against undesired manipulation. The Standard Design of the Anti-Tamper Valve Head Unit is equipped with a bore and matching AT-Key. The valve can only be operated using this special key. The operator can also lock the bore using a padlock in order to prevent the insertion of the AT-Key. This makes it impossible to operate the valve. It can be securely locked in any position – closed, partially open or fully open.
Valves boasting the AT-Key Lock Design are operated using the built-in T Handle Key which can be retracted a little way out of the Valve Head Unit. Once it has been retracted, it is no longer in contact with the stem and activation of the valve is no longer possible. The operator can insert a padlock, which makes it impossible to press in the Key again. The valve is now secured against unauthorized access. This design again permits the valve to be locked in any desired position.
AS-Schneider equips its handwheel-operated Valves with a Locking Plate. This is a metal plate to which the handwheel can be fixed in whatever position is required by means of a padlock. In this design, only minimum movement of the handwheel is possible. It is particularly effective at preventing the unauthorized closure of valves.