Safety Features in SX-Series Autoclaves
Purpose
The safety features of SX-series autoclaves, namely the thermo switch and safety valve, are detailed within this article.
Solution
There are multiple safety features working in the SX-series autoclaves, and during sterilization, the over pressure and temperature protection systems are most active. The main components of each system are the safety valve and thermo switch respectively.
The safety valve is located on top of the autoclave’s lid and opens when internal pressures begin reaching the maximum operating pressure, being around 0.263 MPa for an SX-500 and 0.25 MPa for an SX-700. This safety valve does not rely on any signals from the pressure sensor within the unit, and is entirely mechanical in nature. An example of when this system will come into action would be when an excess of liquid is being sterilized, which would cause the internal pressure to rise above the normal operating pressure.
The thermo switch is a thermal switch connected to the SSR and heating element located underneath the chamber. Once the thermal switch detects an internal temperature of 135 °C, the switch trips, and power is cut between the SSR and heater. Like the safety valve, this safety mechanism is entirely mechanical and does not communicate with the motherboard in the autoclave. One example of when the thermo switch will trip is when turning on the heater without any water in the chamber, preventing any damage to occur to the heating element or other components.