Process Interlocking Closure Locks (CL) During pig launching and receiving, written procedures must be followed carefully. When the vessel is not drained and vented or when the isolation valves are not fully closed before opening the closure, very dangerous situations can occur. The NETHERLOCKS closure lock (CL), as part of an interlocking sequence, prevents these situations by guaranteeing that the isolation valves are closed and the vessel is vented and drained before opening the closure. Because there are many closure types, each design is different, parts of our CL are custom designed for each type and size of closure. However, the design philosophy behind the Netherlocks CL remains the same; in general, opening of a closure requires removal of a bleedbol t. The Netherlocks Closure Lock prevents the bleedbolt from being removed and thus the closure cannot be opened. Only insertion of a unique linear key releases the bleed bolt in order to open the closure. As long as the closure is open, the unique key is trapped. Only when the door is fully closed and the bleed bolt is in its original position, the key, necessary to continue the procedure, is released. The NETHERLOCKS closure lock is suitable for every type and size of closure. Features: o Fully Stainless Steel AISI 316 o Robust, reliable and simple design o Fully maintenance free o Tamperproof o Invulnerable for sand, dirt, snow, ice, etc… o Thoroughly tested to withstand the most extreme operating environments o Optionally, electronic components can be integrated to establish feedback to the control room