Bayonet Lock Closure Pressure Vessels

The KW Designed Solutions Bayonet Lock Closure Pressure Vessel utilises a quick-acting closure based on the principles behind traditional bayonet lock principles.  The Bayonet Lock Closure is an innovatively engineered closure consisting 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 castellations are engaged and removal of the closure plug is prevented.

This type of closure is robust in design, yet provides the operator with quick and simple opening and closing functionality.  Rotation of the locking ring can be done manually via ergonomic handles and manual shot bolt locking mechanism or it can be automated 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 due to the closure plugs ability to house the mate/demate mechanism easily.  Furthermore, this type of closure can be used in either vertical or horizontal orientation.

Bayonet Lock Closure Vessels


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


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

Applications and Customer Uses

The KW Designed Solutions Bayonet Lock Closure Pressure Vessel has proved to be a very popular choice for customers in various industries who require simple, economically priced pressure vessels that still allow relatively quick and easy access.

Customers in the Oil & Gas 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.

This pressure vessel with this type of closure is also a popular choice for customers from scientific and materials research industries working at pressures up to 400 Bar at 200°C as well as those needing smaller bench top reactor vessels, (50ml to 1 litre) for use in laboratories up to 200 bar at 250°C.

Project Examples

Pressure vessel for testing subsea electrical connectors

Pressure testing subsea electrical connectors with mate/de-mate functionality (Ref: SO444, Equip No. 1092)

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
  • Temperature: Ambient
  • Size: Ø180mm x 400mm long
  • Volume: 10 litre

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Pressure vessel testing optical fiber wet mate subsea connectors

FAT testing optical fiber wet mate subsea connectors (Ref: SO823, Equip No. A1092-10-1)

A quick-acting bayonet lock closure at the operational end, this horizontally orientated special purpose pressure vessel provides severe subsea environmental conditions for testing electrical connectors to the offshore oil industry. 

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

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kw designed solutions

Tel: +44 (0) 1257 474 507

KW Designed Solutions Ltd, KW Group, Drumhead Road, Chorley North Business Park, Chorley, Lancashire PR6 7DE. United Kingdom.

Designed and manufactured in the UK Designed and manufactured in the UK.