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Twinlock Quick Opening Closure Twinlock Quick Opening Closure Twinlock Quick Opening Closure


Pipeline Equipment, Inc. has designed and developed a new quick opening closure. This innovative, patented closure system is safe and easy to operate and may be used in a broad range of applications. With more than 15 years of engineering, design and machining experience Pipeline Equipment, Inc. can design closures per customer specifications and meet quick deliveries.

TWINLOCK Quick Opening Closure


Operation of the closure can be accomplished by one person without the use of tools. The integration of the locking segments, locking mechanism and door handle into the door provides a compact and efficient design. To open the door, the handle requires only a quarter turn, which moves the locking segments from their stowed position. The internal components of the locking mechanism are protected by a weather seal and are stainless or plated to protect them from rust and corrosion. The o-ring groove is machined into the door with the hub o-ring seat area recessed to protect the seat during pig launching and receiving. This configuration assures a positive seal when the door is closed and locked.

TWINLOCK Quick Opening Closure


The safe operation of the closure is ensured by a redundant design in which the closure cannot be opened without the removal of the pressure alert valve and the movement of the safety lock. The pressure alert valve also provides the operator an indication of the presence of any residual pressure in the vessel should the operator inadvertently attempt to open the closure prior to all pressure on the vessel being relieved. Additionally, the safety lock mechanism prevents the door handle from being moved to the open position until after the pressure alert valve has been safely removed. The safety lock must also be returned to the locked position in order for the pressure alert valve to be installed.

Product Information

Design Specifications

  • Nominal Diameter Range: 8" - 76" standard, custom sizes available on request
  • Designed and Manufactured in Accordance With: ASME Division VIII, ASME B31.3, ASME B31.4, & ASME B31.8
  • Orientation: Horizontal, Vertical, or Inclined
  • Safety Features: Integrated safety lock and pressure alert valve
  • Pressure Class: 150#, 300#, 600#, 900#, 1500#


  • Hub & Door: SA-105, SA-350 LF2, A-694 F48, Triple Certified
  • Pressure Alert Valve: A-316 Stainless Steel
  • Locking Segments: SA-182, F6A, CL2
  • O-Ring: BUNA-N, Viton, Customer Specified


  • Material: High Yield, Stainless, Other available upon request
  • Weld Bevel: Customer Specified weld bevel
  • Flanged: Available on request
  • Coating: Per Customer Specifications
  • Code Stamp