A flash boiler is a type of water-tube boiler

Water-tube boiler

A water tube boiler is a type of boiler in which water circulates in tubes heated externally by the fire. Fuel is burned inside the furnace, creating hot gas which heats water in the steam-generating tubes...

, whose tubes are strong and close together with water pumped through the tubes. The tubes are kept very hot so the water feed is quickly flashed into steam

Steam

Steam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...

 and superheated. The flash boiler was invented by Léon Serpollet, who used the design in his steam-powered cars

Gardner-Serpollet

Gardner-Serpollet was a French manufacturer of steam-powered cars in the early 1900s.In 1896, Leon Serpollet invented and perfected the flash boiler, which made steam a much more practical source of power for an automobile...

.

Flash boilers are lighter and less bulky than other types, and take less time to raise steam from a cold start. On the other hand they are more prone to overheat, because there is no large reservoir of water to cool the tubes if the water flow is interrupted or inadequate.

Examples

Examples include:

• industrial steam generator
  Steam generator (boiler)
  A steam generator is a form of low water-content boiler, similar to a flash steam boiler. The usual construction is as a spiral coil of water-tube, arranged as a single, or monotube, coil. Circulation is once-through and pumped under pressure, as a forced-circulation boiler...
  
  s
• the water-tube boilers of the monotube type used in steam car
  Steam car
  A steam car is a light car powered by a steam engine.Steam locomotives, steam engines capable of propelling themselves along either road or rails, developed around one hundred years earlier than internal combustion engine cars although their weight restricted them to agricultural and heavy haulage...
  
  s, such as:
  • AMC
    AMC (automobile)
    The AMC was a short-lived British steam car manufactured in London in 1910. The Automobile Manufacturing Company billed the 10 hp vehicle, which had a flash boiler, as being "absolutely safe in the hands of a novice." The car had a top speed of...
    
    
  • Doble
    Doble steam car
    Any of several makes of steam-powered automobile in the early 20th century, including Doble Detroit, Doble Steam Car, and Doble Automobile, are referred to as a Doble because of their founding or association with Abner DobleFox Stephen...
    
    
  • Gardner-Serpollet
    Gardner-Serpollet
    Gardner-Serpollet was a French manufacturer of steam-powered cars in the early 1900s.In 1896, Leon Serpollet invented and perfected the flash boiler, which made steam a much more practical source of power for an automobile...
    
    
  • Locomobile
    Locomobile
    The Locomobile Company of America was an automobile manufacturer founded in 1899. For the first two years it was located in Watertown, Massachusetts, but production was transferred to Bridgeport, Connecticut during 1900 where it remained until the company's demise in 1929...
    
    
• the very simple type of boiler found in pop-pop boats
• Early aircraft
  Aircraft
  An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
  
   engines, such as the one designed for the Du Temple Monoplane of 1874.