Troubleshooting The Bellows

Bellows are nothing more than automatic valves. They open, close, or modulate automatically. The Bellows is a necessity for effective sterilization to occur. In effect, it's function is much like that of a stopper (or plug) in the bathtub.

At start-up, the chamber is filled with air. If air is allowed to remain inside the chamber, the higher temperatures required for sterilization cannot be reached. So it must be evacuated from the chamber.

Air Venting

A Bellows quite literally 'purges' the air, condensates, and other non condensable gases), out of the system, allowing steam to reach its destination in as dry a state/condition as possible to perform sterilization efficiently and effectively.

Inside the Bellows housing, there is a bellows. The bellows is connected to a plate which has a plunger attached to it. When The Bellows is contracted, the plunger location allows air to pass through the valve and onto the reservoir.

Steam causes the Bellows to extend and to push the plunger into an orfice, sealing it shut so steam is not lost and not permitted to enter the reservoir

As long as air and/or condensate is present, the bellows is in a contracted state, and the valve is open. This allows the air and condensate to be vented into the reservoir. The reservoir will bubble intermittently until all air is removed

When live steam reaches the bellows, it extends downward, forcing the valve to close.

This process is repeated until all air has been removed. The bellows then will remain extended, and the valve closed, during the sterilization cycle

What happens when a Bellows no longer works like it is suppose to? There are four conditions:

1. The Bellows no longer fully extends
2. The Bellows no longer fully contracts
3. The Plunger no longer fully seats
4. A Leak Develops

Indications of a Faulty Bellows are

1. The Bellows is Not Fully Closing (fully extending) or The Bellows Valve is not seating properly
   • Constant "Gurling" Sound or Bubbling Coming From The Reservoir
   • Slow Warm up
   • Lower Temperature
   • Lower, or No Pressure
   • Chamber is dry before being vented)
   
   
   
2. Bellows Will Not Open (Remains Closed)
• No bubbling coming from reservoir (Air is not being vented)
• Lower Temperatures
• Lower Pressure

If you can see steam leaking from the Bellows or if the symptoms described above exist, it must be replaced.

The Bellows is considered a normal Maintenance Item That should Be Replaced Annually

Warning: Continuing to operate an autoclave with a faulty Bellows causes additional stress & excessive wear and tear on other components and can cause them to fail as well. Worse yet, it also means sterilization is not taking place.