Slam valve motor, supplying efficient steam engines for homeowners and professional solar installers
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About steam engines

Steam engines have a reputation for being primitive.  This is not true.  Steam engines are the core of coal and nuclear power plants, which generate most of the electricity used by humanity.  Solar thermal power plants, like the hermit gulch CA plant, use steam turbines to generate their power.  Co-gen systems, which enable substantial savings for customers who use steam heat, provide electricity using small steam turbines.  Nuclear submarines use steam turbines, they are not primitive. Steam turbines are and always will be the most economical way to generate electricity from a source of heat in sizes of a megawatt or above.  Smaller turbines have to spin at high RPM and become uneconomical to operate, so piston engines are better for smaller applications.

The steam piston engine was until recently nearly extinct.  It was preserved in models and antiques, to remind us of the mighty engine which powered the industrial revolution.  Until about 1900, just about all sources of power were steam engines based on the James Watt design.  Gradually, gasoline and diesel began replacing the steam piston engines.  The last holdout was locomotives.  Locomotive engines pull a very heavy line of cars and are rigidly linked to them.  When the train first starts moving, the engine has to put out torque at zero RPM.  Diesel has a minimum RPM it can run at, so the transmission has to allow the engine to spin while the wheels remain fixed.  Steam engines can put out torque at zero RPM and therefore don't need a transmission.  In the 1950's, the diesel electric transmission solved this problem and the steam trains died out.

Steam engines had a reputation for long startup times, high maintenance, large demand for water, danger,  and spraying oil everywhere.  These were largely for two reasons.  The long startup time and danger were because they lacked a water pump.  This required enough water in the boiler to last for the entire trip.  The boilers were large, heavy, held a lot of very hot liquid water, and took a long time to warm up.  The danger was from boiler ruptures, the large amount of hot water would be projected at high speed causing injury.  Some steam powered cars used a water pump and a much smaller boiler and would start quickly.  The smaller boilers would not project hot water when damaged,  but the technology died out before this became the norm.

The second reason for the reputation was the problem of emulsion.  The non expansion engines required superheated steam to get useful efficiency.  The superheated boiler required oil free water or else it would burn the oil and generate carbon deposits.  The piston would mix oil and water making a thick mixture called emulsion.  The crankshaft would be exposed to air so as to keep it away from steam and therefore emulsion, and would throw oil everywhere.  The waste steam was generally not recirculated but was simply vented, blowing oil everywhere and causing the engine to thirst for large amounts of fresh water.  All of this was because of the problem of separating out oil from water.

The non expansion nature of the James Watt steam engine also gave low efficiency as compared to diesel.  The steam turbines are expansion motors and therefore much more efficient.  The steam engines made up for this by being able to consume any kind of fuel.  However by the 1950s fuel oil was inexpensive enough to make diesel cost effective even against coal.  While the coal was cheaper, the total cost of maintenance, equipment, and fuel is lower for diesel.

Recently, the longer lifespans of engines and the higher cost of fuel have created a new situation where the total cost of fuel for a vehicle over its lifespan is larger than the total cost of the vehicle.  Suddenly the engine that can run on any kind of fuel can again compete with the one that only takes one kind of fuel.  Also the slam valve motor has double the energy efficiency of the James Watt steam engine.  Also our lower cost fuel is sunlight.  Using an enclosed crankcase, recirculating steam system, and the emulsion eating flooded tube boiler the steam engine can compete with the gasoline engine.  It offers similar lifespan, similar cost, similar maintenance needs.  It wont spray oil or require water.  Also it features twice the peak torque of a gasoline motor.