Slam Valve Motor, supplying efficient steam engines for homeowners and professional solar installers
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Proper safety precautions for steam power systems
Solar power generators
There are three main hazards in solar thermal generators.  The first one is that the motor and generator are linked by a belt drive, and belt drive equipment can remove hands and fingers.  The danger is greater than one might think due to the issue of entrapment.  A loose article of clothing can be drawn into the belt area by the wind created by the equipment, and belt can pull the clothing and associated appendages into the belt/pulley pinch area and remove it in a fraction of a second.  This hazard is present for all belt driven equipment, not just steam engines.  The standard precaution as mentioned in the air compressor manual is to arrange a guard around the belt.  In this case the easiest guard is to put the generator and motor inside a weather proof box which completely encloses the belt and motor.  The box needs to be vented at the bottom but must be rain proof and made of material which can withstand 400 degree F temperatures.  Painted metal enclosures with no grills and no gaskets are preferred.  The enclosure serves to keep hands away from the belt, to protect the insulation and wiring from the elements, and to protect against the second hazard.  Whenever the enclosure is open, it is vital to be sure that the steam system is not pressurized and that the generator cannot be connected to electricity.  The system should not be tested with the enclosure open.

The second hazard of solar generators is a steam system rupture.  The steam system contains high pressure steam and liquid water.  In the event of a rupture, the water may be projected at high speed causing burns some distance away.  To prevent rupture, first always use only pipe and fittings rated for steam use at that pressure and constructed only of a single type of metal.  Galvanized steel water pipe is generally recommended for steam, however the specs on exactly what pressure is recommended are a little hard to trace.  Do not use schedule 40 pipe above 400 degrees F (200 psi).  Schedule 80 pipe and fittings are stronger but again the specs are hard to find.  Never mix metals, this causes rust and eventual failure.  Generally compression fittings use brass so these should not be used with other than brass pipe.  Dielectric junctions don't work at high temperature, so the entire system has to be the same metal.  Never use soldered pipe unless the solder is copper/phosphorus which is rated for high temperature.  Threaded connections are safer.  To keep the pipe within its recommended limits, use an overpressure regulator device on the system.

To reduce the impact of a rupture, the entire steam system should be encased in fiberglass insulation with a rigid outer shell surrounding it.  This includes the steam motor top end.  The steam system must be insulated to work properly, the insulation also serves to divert water spraying through a rupture and slow it down.  Surrounding the insulation must be a rigid but not airtight shell.  This protects the insulation from weather and provides an additional baffle to slow the flow of steam and water in the event of a rupture.  The shell should be aluminum so as not to be combustible if heated to boiler temperatures.  The shell should be vented on the bottom to prevent rain from entering.

The third hazard of solar generators is evacuated tube fracture.  The inner layer of the tube is above 400 deg F when operating.  Imagine a baseball hitting one of the tubes.  Keep the glass from hitting anyone or landing on anything combustible.  A metal mesh surrounding the tube reduces efficiency slightly but improves safety for non rooftop installations.

Vehicles
For vehicle power plants,   sudden loss of power is very dangerous.  Steam system rupture should be made extremely unlikely by proper choice of piping and mounting.  Strain relief the pipe connections properly as the motor itself can vibrate relative to the body of the vehicle. Ideally multiple steam systems in parallel improve safety.  As with the solar power plants,  keep the steam system well isolated from people or anything at all combustible.  Consider how things might move if the vehicle is in a collision. An overpressure relief valve is manditory.

Similar to electric cars, the battery creates a safety challenge.  It needs to be well mounted so as to not break free in a collision.  Combustible materials need to be kept away from the battery.  This includes asphalt ; the battery must not sit on the road after a collision.  The battery needs to be well away from the fuel system.  Expect the insulation to fail after a collision; the battery needs to be suspended above the road and away from the passenger compartment and away from any combustible material.