AI-187 Single Stage


GD Engineering is a world leader in the manufacture of quick opening closures. Our GD Bandlock™ 2 is the original and benchmark design for global high pressure applications with over 20,000 units in operation worldwide.


GD Bandlock™ 2 Closures provide horizontal or vertical access to any pressure vessel in seconds. Compared with other quick-opening closures they can be operated safely at remarkable speed — any size of unit can be opened or closed in less than a minute, with no special tools required.


Computer-aided technology has played a large part in the design of Bandlock™ 2. The main pressure loaded sections have been designed to save weight by employing finite element analytical techniques and proof testing by strain gauges, while still adhering to primary pressure vessel code requirements.


The tried and tested locking band mechanism which gives the range its name is a duplex stainless steel conical thrust ring fitted between the door and hub, transmitting the pressure load uniformly around the full 360° circumference of the hub.



Integral Safety Devices


Safety has been engineered into the Bandlock™ 2 at every stage of its design and manufacture. A hand-operated pressure warning screw integrated into the mechanism prevents the door being unlocked until it is confirmed that the vessel’s internal pressure has been relieved. Additional secondary safety features, such as mechanical key interlocks, can be fitted and integrated with control valve operations.

For complete safety, the locking band can be seen at all times, which satisfies design code requirements and means that the operator can actually see that the door is securely closed and locked.


Door Hinging


For horizontal use the door is double pivoted on hinges with self-lubricating bearings. The bolted fitment allows adjustment for wear and can be specified for right or left swing. Vertical installation includes a davit which enables the Bandlock™ 2 door to be lifted and swung clear of the hub. At diameters over 30”, lifting eyebolts are normally fitted instead of the davit, so that the door can be lifted out of the way.


Seal Material


The standard seal is 80° shore hardness Nitrile material. Viton, HNBR and explosive decompression-resistant materials grades are also available. Temperature range is -45°C to +210°C according to the elastomer specified.


Hydrostatic Testing


Normally carried out as part of the final vessel test but an individual closure hydrotest can be provided as an option.

Unique Seal with Integral Anti-Extrusion Spring

To give a completely pressure-tight seal, the purpose designed servo acting lip seal energizes at zero pressure. For both Horizontal and Vertical Installations the seal is housed in the door away from the working area for protection and long life, and is easily fitted without tools. The one-piece molding is available in a range of elastomers and incorporates a stainless steel spring to prevent extrusion and provide a full vacuum capability.




Forged steel hubs with forged or plate doors can be supplied to meet all international material specifications. NACE Standard MR-01-75 / ISO 15156 materials are available.

Approved Design


Standard units meet ASME VIII Div.1. The requirement of other pressure vessel codes, such as ASME VIII Div. 2 and PD5500 can be accommodated. ASME Code Stamp with U-2A partial data report can be furnished as an option. Code stamping verifies shop inspection of the closure and materials by an ASME

Authorized Inspector.


European Pressure Equipment Directive (97/23/EC)


The following options are available:

Technical file — submitted to vessel fabricator for incorporation into CE Marking of vessel

CE Marking of Closure by GD Engineering

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