Astell double-door SQUARE autoclaves give laboratories and production facilities a chamber for processing loads and transferring them between separate areas. A door at each end allows loading on one side and unloading on the other, supporting controlled transfer in cleanroom or containment applications. Each steam sterilizer is built to order, with options for vacuum air removal, drying and faster liquid cooling.

Choose from chamber capacities of 250 to 3,000 litres, with the chamber dimensions, loading arrangements and transfer controls specified around your load and facility. Available combinations depend on the configuration. Autoclaves with designs or chamber sizes outside the specifications of the standard Astell ranges are available as Custom Units. Chambers larger than 3,000 liters are available subject to engineering review.

Double-door designs are typically based on the SQUARE or SQUARE MAX ranges. The SQUARE uses vertically sliding doors; for taller chambers or lower loading heights, investigate the sideways-sliding SQUARE MAX design.

Design around the transfer process

Start with the items that must pass between the two areas. Their dimensions, materials and loading arrangement determine the chamber and cycle requirements. Allow for baskets, trays or loading carriages as well as the items themselves. Anything too large for the usable opening or chamber cannot travel through this route.

Door interlocking (controlling whether both doors can open at the same time or not), cycle-dependent release (if, when, and which door unlocks based on the specific cycle selected and its outcome) and the required direction of transfer should be agreed as part of the specification. A controlled transfer process depends on the complete installation and its operating procedures, as well as the autoclave’s sterilization cycle. Read more in Features to consider when purchasing a pass-through autoclave.

The processing options must also suit the load. Liquids need controlled heating and cooling, while bagged discard, wrapped items and complex equipment may need effective air removal. Where loads must leave the chamber dry, specify vacuum, a heated jacket and a suitable steam supply.

Throughput matters because the autoclave can become a bottleneck in the transfer workflow. Liquid loads can take a long time to cool without suitable cooling options, delaying the transfer of subsequent loads. Astell can assess the required cycle frequency and recommend a chamber size and processing configuration.

Barrier seals and facility integration

For a wall-mounted pass-through installation, a Specific Pathogen Free (SPF) bacteriological seal can be specified to seal the interface between the autoclave and the surrounding barrier. The seal and installation details must suit the facility’s separation requirements.

Containment applications, including Containment Level 3, may require exhaust filtration and effluent retention or treatment. These requirements should be assessed alongside the load, transfer direction and facility design. Astell can discuss specialist integrations, including interfaces with Class III biological safety cabinets or gloveboxes.

Monitoring and controls on both sides

A secondary display can be fitted beside the second door so operators in both areas can monitor cycle progress. Controls can also be provided on the second side, with permitted functions and access agreed as part of the operating arrangement.

Explore the processes in more detail

Getting liquid cycles right

The other half of the job

Why sterile isn’t always dry

Where autoclave cycle time actually goes

Discuss your pass through requirements

Tell us the load dimensions and materials, the required transfer direction, the nature of the two areas, the expected throughput and the services available on site. Astell can work through the chamber, barrier, cycle and loading arrangements with you, then provide a specification and quotation for the proposed installation.

Call +44 (0)20 8309 2031 or request a quotation.