UMA270BT - 135L Top Loading Sterilizer

The Astell top loading sterilizer range builds upon the smaller Compact range of top loading sterilizers by offering larger chamber sizes and also a variety of additional options which increase the versitility of the autoclave.

This model is suitable for sterilizing:

  • Liquids (media)

  • Discard

  • Glassware

  • Laboratory Instruments

This model features

  • A fully programmable touch screen color controller

  • An electro polished stainless steel chamber

  • Delayed start and media holdwarm feature

  • External pressure guage

  • Safety valve test program and emergency stop button

  • Validation port

  • Drain valve

  • Castor mounted

  • Timed/Pulsed freesteaming

With the additional of certain options available, this model of autoclave can be manufactured to your specific requirements. As standard, the autoclave is fitted with heaters in the base of the chamber, although this model is available as a 'Direct Steam' model (if an on site steam supply is available) or fitted with an 'Integral Steam Generator'.

Technical details - UMA270BT (Standard model)

All of the details below are based on the standard model with no additional options or accessories. As such, the addition of these options may alter the power requirements and dimensions. Please contact us for futher information.



Model Number/Type:

UMA270BT - Top Loading Autoclave

Steam Source:

Heaters in the Chamber


135 litres

Power Supply:

Single or 3 Phase, 7/10kW

Chamber dia x depth

456mm x 680mm

Overall Dims (w x h x d)

660mm x 1150mm x 840mm

Power Requirements

The power requirements for the standard machines are specified in the table above, however these can vary depending on the options selected. Options that affect the power requirement generally include the addition of a steam generator or a vacuum. For exact power requirements on these options please contact us for details. N.B a Neutral line and protective Earth are required for all electrically heated units.

Water and Drainage Requirements

A cold water supply of 2 to 6 bar minimum is required. 4 litres/min is required to operate the 'Autofill', vacuum or water cooling options. Maximum water temperature should not exceed 25°C, with a maximum flow rate of 20 litres per minute. Requirements vary for RO/de-ionised/hard water - please contact us for futher information.

Drainage: A free-venting, non-manifolded drain (35mm dia) is required, capable of withstanding temperatures up to 100°C.

Different steam sources available:

(Hc) Heaters in Chamber

'Heaters in chamber' is the standard configuration fitted to the UMA top loading range of autoclaves. On standard machines, water is manually poured by the user directly into the chamber before each cycle begins. As the heater element(s) reach temperature, the water in the chamber boils to produce steam. An 'Autofill' option is available to allow automatic water filling to take place from a mains water supply. This configuration is not suitable for sterilization cycles where drying is required for porous loads.

Steam Generation Options

(Sg) Integral Steam Generator

The integral steam generator option removes the heating elements from the chamber and replaces them with an integral generator (which is external to the chamber) for improved control over steam production. 'Autofill' is also fitted as standard to the steam generator; eliminating the need to manually refill the chamber between cycles. A mains water supply enters the steam generator, where it is heated and converted to steam.

Steam Generation Options

(Ex) External Steam Source

The external steam option is intended for sites which already have a steam supply available, therefore have no requirement for an integral steam generator. An external steam feed enters the unit as per the illustrated diagram. To order direct steam, the last digit of a standard Model number is changed to a '2'. i.e an UMA250BT would become an UMA252BT.

Steam Generation Options


This area indicates whether a particular option is available with your required steam method.
If the option is greyed out, it means that this option is not suitable for the steam type you require
If an option is red it means this is available with your required steam type.

Integral Data Printer - REF: AAR130

This printer provides a permanent and traceable record of: Time, Temperature, Pressure, Batch No. and Cycle Name. There is also provision for operator signature; the printer also provides reports of cycle settings and servicing information.

Astell Scientific Printer

RS232 Interface - REF: AAR120

The addition of the RS232 option allows cycle progress to be monitored (via HyperTerminal) on an external computer equipped with suitable software.


Ethernet Interface - REF: AAR122

The addition of the Ethernet interface allows the visual display of the colour touch screen controller on another device. This works by using a VNC Viewer (not supplied) and a PC or other hardware capable of running VNC.


IQ/OQ Documentation - REF: IQ/OQ

The IQ/OQ documents package provides the user with blank documents for them to complete. The IQ section includes details of calibration equipment, an order Acknowledgement, PED (Pressure Equipment Directive) Compliance, a Declaration of Conformity, FAT (Factory Acceptance Test), a Drawing Schedule, ISO 9001:2008 Certification, Pressure vessel specification and door safety checks. The OQ Documentation includes an Automatic control test sheet (per cycle) and Chamber temperature distribution (per cycle)
Please note: This is our standard IQ/OQ Documentation package.


Morrison Discard Containers

Morrison Discard Containers are available in two sizes as follows:

  • 390mm diameter x 355mm high - Astell REF: AAN058
  • 390mm diameter x 500mm high - Astell REF: AAN056

Please note: The image shown may refer to a different Morrison Discard Container to that supplied

Astell Discard Container

Stainless Steel Basket

Stainless Steel Baskets are available in two sizes as follows:

  • 400mm diameter x 220mm high - Astell REF: AAN042 (Holds 3)
  • 400mm diameter x 400mm high - Astell REF: AAN036 (Holds 1)

Please note: The pictured image refers to a different Stainless Steel basket.

Astell Stainless Steel Basket

Load Related Options

Load Sensed Process timing - REF: AAR014

Load Sensed Process Timing allows the sterilization cycle to be controlled via the temperature achieved in the centre of the load. The operation of load sensed process timing is controlled via the ‘Logi’ touch screen controller. A ‘wandering’ probe, situated within the chamber is inserted into the load, or load simulator, and initiates the sterilization period once the probe reaches the programmed threshold temperature.

Load Sensed Process Timing

Air Ballast - REF: AVC004E

Air ballast is especially useful for fluid cycles as it provides controlled reduction of the chamber pressure during the cooling phase. Effectively this prevents the ‘boiling over’ of bottled fluids that is frequently associated with rapid cooling systems.

Air Ballast Option

Advanced Vacuum Options - Astell Ref: AVC001s

A vacuum option is essential for porous loads (e.g wrapped instruments and fabrics) or other cycles where air pockets could easily become trapped within the load. The AVC001s option is Astell’s advanced pulsar vacuum, which when used in conjunction with the integral steam generator and a heated jacket enables the dry output of all loads.

Vacuum Option

External Jacket Heating - Astell Ref: AJP150

Requiring the steam generator (or direct steam supply) option (and normally in conjunction with the AVC001s vacuum option), external jacket heating effectively adds an additional layer to the outside of the autoclave chamber. This can then be independently heated by the steam supply to allow drying to take place at the end of a cycle, or can be flooded with water during cooling to aid cooling times.

Jacket Option

Cooling Related Options

Assisted Air Cooling - REF: AAP006

A powerful external fan helps to reduce cool down time. The operation of the assisted air cooling system is controlled via the ‘Logi’ colour touch screen and is available on all models as an additional option, except for those fitted with a vacuum.

Assisted Cooling Option

Advanced Water Cooling - REF: AAP080

Water is circulated through cooling coils in direct contact with the outside of the autoclave chamber, resulting in the rapid decrease of the internal chamber temperature. Advanced water cooling offers substantial time saving and is ideal for the busy Laboratory.

Water Cooling Option

Autodrain Option - REF: AAP018

For use in heaters in chamber autoclaves only. This feature can be selected on any cycle and will substantially decrease the time required to cool the chamber to a temperature where the door can be safely opened, especially when used in conjunction with the advanced water cooling or assisted air cooling (as detailed above). At a pre-selected pressure during the cooling phase of the cycle, any remaining water in the chamber is evacuated to the drain. As the discharge water will be approx. 100°C we would highly recommend that the ‘exhaust heat exchange system’ (AAN420) is ordered in conjunction with this option as well as the ‘Autofill’ (AAP019) to avoid having to manually refill the chamber with water at the end of each cycle.

Autodrain Option

Installation/Maintenance Options

Autofill Option - REF: AAP019

The ‘Autofill’ option automatically maintains adequate water level within the chamber (for Heaters in Chamber models only). The water inlet is controlled by a level switch and complies with water bylaw regulations. The unit is readily connected to the water supply via a 1.5m flexible hose (supplied).

Autofill Option

Water Softener - REF: AAW002

Recommended to reduce the build-up of limescale on heaters and pipework etc, and particularly recommended for units with steam generators. Unit includes a separate brine tank, allowing installation in difficult or restricted positions. Requires salt. (full details, including service requirements are available upon request)

Astell AAW002 Water Softener

Exhaust Heat Exchange System - REF: AAN420

The exhaust heat exchange system is only for standard units with the heaters in the chamber, due to the fact it's primary purpose is to reduce the temperature of fluid leaving the chamber rather than steam. This option to significantly reduce the temperature of the exhaust/waste in situations where heat resistant drains are not present. N.B. Requires a mains water supply.

Exhaust Heat Exchange Option

Category 3 Compliance - REF: AVQ006TL

Category 3 compliance is often required when dealing with high risk sterilization requirements. A bacterial retentive filter fitted onto the exhaust ensuring nothing leaves the chamber without being sterilized.
Note: Filter may vary from that pictured.

Category 3 Filter Option

Contact Astell Inc

To enable us to quote you as quickly as possible, please let us know the following in your message:

  • Are you sterilizing any fluids?

  • Are you sterilizing any wrapped instruments or fabrics?

  • Are you sterilizing anything other than glassware, plastics or media?