A compact apparatus for production of steam for use in heating, ventilation and air conditioning of buildings and in industrial processes requiring clean steam, said apparatus including:
- a) combustion means provided for generating heat by combustion of a fuel with combustion air, said combustionmeans including combustion control means, gas valve means, fuel burner means, dry firebox chamber means, flue gas discharge means and high temperature limit control means, said combustion control means being provided for regulation of said gas valve means and safe operation of said burner means, said fuel burner means being provided for burning of said fuel in said firebox chamber means, said firebox chamber means provided for combustion of said fuel with combustion air to generate hot combustion gases to provide the required process heat, said firebox chamber means including (insulated) walls defining an open (top) cavity having interior side and bottom wall surface, said flue gas discharge means provided for discharging of said (cooled) combustion gases out of said firebox chamber means to outdoors, and said high temperature limit control means provided for protecting said flue gas discharge means against overheating by said combustion gases.
- b) boiler means including steam chamber means integrated with vertical boiling means, said boiler means (located in said cavity and closing the open top of) integrated with said firebox chamber means having (spaced from selected ones of said cavity) extended heat transfer surfaces, said extended heat transfer surfaces having spacing providing an air flow passage for said hot combustion gases from said burner means through said firebox chamber means to said flue gas discharge means, said steam chamber means including partition means for separating steam bubbles from recirculating boiling water therein and having an outlet therefrom for discharge of said separated steam and an outlet for blow down of said recirculating water, said vertical boiling means provided (with heat transfer surface means) for transferring said process heat from said hot combustion gases to said recirculating water therein and boiling said recirculating water therein to produce said steam bubbles therein and to recirculate the boiling water therein to maintain the formed precipitate in suspension in said recirculating boiling water, said boiler means having an inlet for feed water for production of said steam discharged from said steam chamber means and for said blowdown of said recirculated water,
- c) feed water means provided for supplying said feed water to said boiler means interconnected with a high and low water level sensing means for controlling the flow of said feed water and for maintaining the water level in said boiler means within a present high and low water level limits,
- d) variable time relay means automatic periodic blow down of said recirculating water from said boiler means to maintain the concentration of suspended solids in said recirculating water at predetermined concentration.
- e) conduit means for pressure sealing said boiler means and for discharge of said periodic blow down of said recirculating water to sewer means, and
- f) plumbing means provided for an intake of said feed water into said boiler means, for an intake of said fuel into said combustion means and for draining of said boiler means to sewer means.