Safety in steam engines is an important issue that needs to be studied and prevented due to the characteristics of this type of machine.
The composition of the steam machines formed by boilers and other components under pressure causes fluids with a very high potential energy to be stored. Due to the high pressure and temperature with which you work any steam or explosion leaks can be very harmful for the safety of people.
Throughout the history of steam engines there have been very serious accidents that have involved considerable material damage and even the loss of human lives.
Due to the accidents of the first stages of the steam they determined they began to develop a very severe legislation with the aim of improving the safety of the steam engines and reducing the risks. Depending on each country these laws vary but, in general, require a series of tests and certificates in the various phases of manufacture, commissioning and service of each machine.
Main causes of accidents in steam engines
To establish safety protocols in steam machines, we must first know the events that cause these accidents. The main causes of failure and accident are the following:
- Accumulation of sediments or calcification, causing too high local temperatures (hot spots)
- Overpressure of the boiler
- Lack of water in the boiler, causing a temperature of the components higher than they can resist
- Boiler failure due to faulty construction or inadequate maintenance.
- Steam leaks from the boiler and pipes, causing a steam jet that can scald very badly (an escape of saturated steam into the atmosphere is clearly visible, the superheated steam is less visible and dangerous).
Vapor-machine safety valves
The steam pressure of a machine can be regulated by the user. This regulation can be carried out directly by a manual valve, or indirectly with a suitable system (electrical or electronic).
These different regulation systems are not infallible. Therefore, to improve safety, steam machines have safety valves that open when the pressure reaches a certain value (lower pressure than the components can withstand).
A safety valve is a final protection element against mechanical and / or human failures.
- Classic safety valves could be manipulated to increase the maximum pressure. There are safety valves that protect the regulating crumb with a closed and sealed device, which is more difficult to handle.
- Another safety feature is a lead fuse installed in the boiler. The objective would be that, when the water level drops, when the fuse blows the steam can escape. The effectiveness of this system is discussed.