Our KW Designed Solutions designed and developed bayonet lock closure high pressure testing vessels utilises a quick-acting closure, which is based on the principles behind traditional bayonet lock principles. The bayonet lock closure is an innovatively engineered closure. It consists of a locking ring with castellated slots machined to its ID and a closure plug, with a matching set of castellated lugs, machined to its OD. When the plug is inserted, the locking is rotated 1/8th or 1/16th of a turn, until both pairs of castellation’s are engaged; preventing removal of the closure plug.

This type of closure is robust in design, yet provides the operator with a quick and simple opening and closing. Rotation of the locking ring can be done manually via ergonomic handles and manual shot bolt locking mechanism or we can automate the function with actuation devices and safety interlock systems.

Pressure vessels designed and manufactured with this type of closure are typically used to carry out static or dynamic Factory Acceptance Testing (FAT) on subsea electrical connectors. The closure plugs provide the ability to house the mate/ demate mechanism easily and they can be used in either vertical or horizontal orientation.

Bayonet lock closure


  • 1/8th or 1/16th turn Locking Ring (can be actuated if required)
  • Materials of construction: Stainless steels, Carbon and Alloy Steels
  • Pressure Rating: 100 bar to 1500 bar
  • Seal Types: O Seal with PTFE Back-up Ring
  • Size: Between Ø100mm to Ø300mm bore and depths of 200mm to 1000mm
  • Temperature: -20°C to 200°C
  • Volumes: 1 litre to 100 litres


  • Custom size and pressure range available to meet specific requirements
  • Guided closure alignment system allowing easy and safe operation
  • Ideal for use when mate/ demate functionality is required
  • Integral safety interlocking system
  • Quick acting opening/ closing times: 1 minute to open/ close, 5 seconds to lock/ unlock
  • Simple 1/8th or 1/16th of a turn locking functionality – the minimum effort required to engage the closure

Applications and Customer Uses

Our bayonet lock closure pressure vessel is a very popular choice for customers in various industries who require simple, economically priced pressure vessels; whilst still allowing relatively quick and easy access.

Customers in the energy and subsea sectors use bayonet lock closure pressure vessels for API 6A product verification, subsea factory acceptance testing (FAT) and subsea production testing of subsea electrical connectors, hoses, cables, penetrators and valve seal arrangements.

It is also a popular choice for customers from scientific and material research industries; working at pressures up to 400 Bar at 200°C and those needing smaller bench top reactor vessels (50ml to 1 litre) for use in laboratories up to 200 bar at 250°C.

Bayonet Lock Closure Pressure Vessels Enquiry

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Project Examples

Pressure vessel for testing subsea electrical connectors

This special-purpose pressure vessel, with the bayonet quick-acting closure, incorporates a manual interlock has been designed to carry out factory acceptance tests on subsea electrical connectors.

  • Pressure rating: 517 bar
  • Size: Ø180mm x 400mm long
  • Temperature: Ambient
  • Volume: 10 litres
Pressure vessel testing subsea electrical connectors with mate and de-mate functionality
Pressure Vessel with mate and de-mate functionality for Factory Acceptance Testing optical fiber wet mate subsea connectors

Pressure vessel testing optical fibre wet mate subsea connectors

This horizontally orientated special-purpose pressure vessel, with a quick-acting bayonet lock closure at the operational end, provides severe subsea environmental conditions for testing electrical connectors to be used by the offshore industry.

  • Pressure rating: 569 bar
  • Size: Ø180mm x 1000mm long
  • Temperature: Ambient
  • Volume: 25.5 litres