The Vertical Autoclave

Ask a lab manager about their vertical autoclave and they'll tell you about the time their lid wouldn't seal, or the water that boiled over, or the packs that came out still wet. They're very forgiving devices, but the people who get the best from them are the ones who know what goes on inside. Here are the operating procedures and troubleshooting tips that I've found to be most effective.

The Reasons a Vertical Autoclave Deserves Respect

The vertical autoclave is a pressure vessel that sterilizes by using saturated steam heated to 121°C and 15 psi of pressure. And while that pressure and heat is why it works, it's also why cutting corners isn't wise. Always treat your vertical autoclave as you would any pressure equipment.

Safe Operating Practices

Prior to the Cycle

Make sure to check the level of the water in the unit against the marked line and use distilled water, because mineral scale forms on the heating element and sensors. Check the door seal for cracks or flattening and ensure the vent and safety valve are free from obstructions. Place the items loosely into the chamber and leave caps on bottles slightly loose.

During the Cycle

Do not start the exposure time until the pressure gauge reaches the required pressure mark, and not the moment you turn the heater on. Be close by for the first few minutes, because leaks and venting issues manifest themselves at that stage. Do not open the lid while the pressure gauge shows pressure.

After the Cycle

Wait until the pressure drops to zero and the chamber cools down slightly before opening it. Open the lid with your face turned aside, because the residual steam might burn you. Use heat-resistant gloves and a face shield when handling the hot liquid.

Common Issues and Solutions

If there is steam escaping from the lid, the problem lies in the gasket being worn out, soiled or improperly placed; clean the gasket and then reinstall it. When the unit fails to generate pressure, check the water level, vent valve and gasket in sequence. Wet clothes are caused by overloading and improperly arranged items, whereas loosely packed goods with extended drying process help solve the issue. For frequent tripping of the heating element, scale buildup is usually the reason; descale the chamber based on the manufacturer’s specifications. It goes without saying that the error codes must always be verified with the manual.

Evidence of Success: Validation and Documentation

A clean cycle does not guarantee sterile results; always use chemical indicator tape on all cycles as well as a biological indicator weekly as necessary by protocol. Always keep an official log of the date, type of load, temperature used, cycle time and the user. Auditors require documentation as proof of traceable cycle times. Biological indication failure means shutting down the machine, reviewing your technique in loading and timing, and testing again prior to using the machine.

Criteria to Choose a Vertical Autoclave for Safely

Think about using double safety valves and interlocking door system so that doors will not open during high pressure. Stainless steel construction is better than coated chamber and digital controllers which makes it easier to program cycles and minimizes human mistakes. Please inquire about CE or ISO certification and local services.

Common Questions

Is a vertical autoclave safe to use daily? 

Yes, as long as you use the correct amount of water, load properly and respect the safety features.

Why isn’t my vertical autoclave building up pressure? 

The most likely reasons are low water, a vent that’s open or a worn gasket.

How often should I replace the gasket? 

Check monthly and replace the gasket when it hardens, cracks or leaks – usually every one to two years.

Concluding Thoughts

A properly maintained vertical autoclave will be quiet, reliable and safe. Establish the good practice of checking the water and gasket, running the cycle at the correct time, using indicators to confirm sterilization and maintaining records, and the autoclave will reward you with years of trouble-free operation. Click here to Know More.