Closure locks Process Interlocking

The Netherlocks Close Lock is custom designed to interlock the closure door of a pigging vessel. The Closure Lock prevents the bleedbolt from being removed and thus the closure door from being opened. Only the insertion of a dedicated key frees access to the bleedbolt, so it can be removed. This key is only released after the door is closed and the bleed bolt is back in place. The Closure Lock is suitable for evey type and size of closure door.

Valve interlock for closure door

The Closure Lock prevents the bleedbolt from being removed and thus the closure door from being opened

During pig launching and receiving, operating 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 door, 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 the closure door can be unlocked and opened.

Closure Lock  features

  • No grease or other lubrication required
  • Ingress protection of key slots by self sealing weather strips
  • Locks the closure door as an integral part of an operating sequence
  • Suitable for every type and size of closure door
  • Traps the bleedbolt on the door until the release key is entered
  • Option for electronic locking until H2S and pressure levels are within acceptable range
  • Option for detecting open position of the closure door with a sensor

Closure door valve interlock for pig launching and receiving

Custom design

Each Closure Lock design is different for each type and size of closure. For GD Engineering closure doors, standard CL designs are available.

  • The brackets are commontly mounted on the flange of the closure door
  • For mounting of the brackets, drilling is required
  • Mounting can be done during operation since the door does not have to be operated
  • Only tamper proof bolts are used
  • Brackets are designed to the specific closure door dimensions. Detailed dimensions of the door are required to start design.

Download the Netherlocks Closure Lock product sheet (PDF)