Our manual chock closure pressure vessels provide the end user with a closure that has been innovatively engineered; providing an alternative to the bolted closure for medium sized pressure vessels.

The closure plug is retained by a set of ergonomically designed, segmented chocks that the operator can easily handle. This allows the robust closure to be locked and unlocked in a matter of minutes, helping to improve efficiency and reduce operator fatigue.

When fully assembled, the chock ring is self-locking. This provides a sound mechanical safety feature, preventing the accidental removal of any of the segmented chocks.

The compact nature of the manual chock closure allows the body of the pressure vessel to be shorter in height, fitting into facilities where this may be a restriction. Used in the vertical orientation these vessels have a minimal footprint; taking up little shop floor space whilst still allowing simple fitment of slim heating and cooling jackets.

Due to its simplicity, only the closure plug requires handling, with an overhead hoist system during opening and closing. However, with the closure plug typically being of a similar weight to the DUT, being hoisted in and out of the pressure vessel, it allows for the installation of a hoist with a low to moderate lifting capacity.

pressure vessel designed to carry out qualification and FAT of subsea flexible riser buoyancy modules or Distributed Buoyancy Modules and Drill Riser Buoyancy Modules


  • Closure Time: From 3 mins to 5 minutes
  • Material of Construction: Stainless Steels, Carbon & Alloy Steels
  • Multi-Penetration Closure
  • Pressure Rating: 100 bar to 700 bar
  • Seal Type: O Ring with PTFE back-up-ring.
  • Size: Between Ø400mm to Ø750mm Bore & Depths of 800mm to 2500mm
  • Temperature: -20°C to 200°C
  • Volumes: 100 litres to 1000 litre


  • Custom Size & Pressure Range Available to Meet Specific Requirements
  • Easily Identifiable Chocks; Colours & Numbers Ensure Correct Sequence to Prevent Accidental Opening
  • Long Service Life
  • Low Maintenance Requirements
  • Multiple Penetrations for Tooling, Electrical Feed-Through & Pressure Control Hardware
  • Plug Guidance for Larger Closures
  • Semi-Quick Acting Opening & Closing Times: 2 Minutes to Open/ Close, 2 To 5 Minutes to Lock/ Unlock
  • SWL Rated Closure for Attachment of DUT (Device Under Test) – Reducing The Need For Separate Handling

Applications & Customer Uses

Our manual chock closure pressure vessels are a popular choice for our customers within the energy and subsea sectors. The simple & ergonomic design of the chocks make this closure a more favourable manual method, when compared to bolted closures that require heavy duty bolting.

Typically, this type of pressure vessel is used for FAT or production testing of subsea electrical components, hoses, cables, feed through penetrators and subsea flexible riser buoyancy modules or (DBMs) in-line with API16F & API17L.

Please follow the link below – designed, manufactured, installed and commissioned manual chock closure vessels at Balmoral Offshore Subsea Test Centre in Aberdeen.


Project Example

Pressure vessel testing distributed buoyancy modules
Pressure vessel for testing subsea distributed buoyancy modules

This pressure vessel was developed to carry out qualification & FAT of subsea flexible riser buoyancy modules or (DBMs).

  • Pressure Rating: 600 bar
  • Size: Ø500mm x 2500mm depth
  • Temperature: 0°C to +100°C
  • Volume: 490 litres

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