Valve Interlocks

What are valve interlocks?

A valve interlock, is placed between the valve and the actuator and locks the valve in the fully open or closed position.

Valve interlocks work through a trapped key system. This mechanical key interlocking system ensures that coded keys are released and locked in a predetermined sequence. The valve interlock thus guarantees that the valves are only opened or closed when the required conditions are met.

Fireproof API607 and INOX 316

Fully mechanical

Resistant to sand, soil and humidity

Valve Interlocks

Mechanical interlocks for locking different types of valves

DML/SML

Key interlocks for handwheel valves

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DQL/SQL

Key interlocks for ball valves

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Mechanical Interlocks for handwheel valves

Alcatraz integral multi-turn (type DML/SML) valve interlocks fit all types of handwheel operated valves, such as slide valves and globe valves, and are easily placed between the handwheel and the valve with an adapter piece.

Multi-turn mechanical interlock systems for handwheel valves. Locks and unlocks keys only in a fully open or closed position. The handwheel can therefore only be operated when both keys are inserted, after which key A can only be removed in the open position and key B can only be removed in the closed position.

Full mechanical interlock
Manufactured from stainless steel AISI 316
Compact design
Highly coded key system prevents manipulation
Fireproof according to API 607 sixth edition test
Resistant to sand, dirt, humidity and chemicals
Tested for low temperature operation
Ergonomic positioning of lock mechanism

Robust Design

Alcatraz DML or SML interlocks have a compact design with a minimum of moving parts for years of trouble-free operation.

Fully corrosion-resistant

Alcatraz valve interlocks are completely made of stainless steel 316, the stainless steel locking mechanisms are also equipped with spring-loaded protective caps to limit contamination of the mechanism.

Key detection

Alcatraz offers the possibility to equip the interlocks with (ATEX) limit and/or proximity switches for the detection of the key and position of the valve.

Mechanical interlocks for lever operated valves

Alcatraz DQL and SQL interlocks are specially designed for quarter turn lever operated ball valves and butterfly valves. This interlock system is also integrated between the actuator and valve for easy operation.

By using an adapter set, DQL and SQL valve locks can be easily installed on existing lever-operated valves, even when the valve is under pressure.
Only when both keys are inserted into the lock can the valve be operated. The first key can only be removed in the fully open position, the other key can only be removed in the fully closed position.