Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23B—METHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
  • F23B50/00—Combustion apparatus in which the fuel is fed into or through the combustion zone by gravity, e.g. from a fuel storage situated above the combustion zone
  • F23B50/12—Combustion apparatus in which the fuel is fed into or through the combustion zone by gravity, e.g. from a fuel storage situated above the combustion zone the fuel being fed to the combustion zone by free fall or by sliding along inclined surfaces, e.g. from a conveyor terminating above the fuel bed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24B—DOMESTIC STOVES OR RANGES FOR SOLID FUELS; IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES
  • F24B1/00—Stoves or ranges
  • F24B1/02—Closed stoves
  • F24B1/024—Closed stoves for pulverulent fuels
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24B—DOMESTIC STOVES OR RANGES FOR SOLID FUELS; IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES
  • F24B13/00—Details solely applicable to stoves or ranges burning solid fuels 
  • F24B13/04—Arrangements for feeding solid fuel, e.g. hoppers 

Definitions

• the present invention relates to a device for dispensing pellets for a stove.
• the invention also relates to a stove with such a device.
• a stove fired by pellets is a heating apparatus, nowadays increasingly widespread especially in domestic settings.
• Such an apparatus burns wood pellets to generate heat.
• a stove fired by pellets comprises:
• stoves fired by pellets make it possible to burn biomass that is traditionally less amenable to combustion than gas, so obtaining two advantages:
• Such mixing makes it possible to provide a reactive system that is more evenly distributed in space, one that is much less affected by the unevenness typical of a wood log, which burns with a combustion front that proceeds inward from outside.
• the dosing makes it possible to control the flow of pellets and the flow of air by acting on the rotation speeds of the screw feeder and of the fume extractor, in so doing modulating the power dispensed by the appliance, according to requirements.
• the overall effect of the combustion of ligneous biomass reduced to pellets is to render the combustion more stationary, and, with a suitable pellet/air dosage ratio, more efficient and less polluting than that of a wood log.
• the pollutant substances with which to quantify the environmental impact of a stove fired by pellets are made up of emissions of:
• the screw feeder for conveying the pellets from the hopper to a brazier although it rotates continuously as it draws the pellets from the hopper, is not capable of providing a constant pellet flow rate owing to the variable length of the pellets, even in the case of pellets from the same bag emptied into the hopper, and owing to the unpredictable orientation of the pellets with respect to the base of the screw feeder.
• the release of the pellet from the screw feeder to the brazier is impulsive, and instantaneous discharges of pellets alternate with periods of complete absence of flow, with consequent development of flames of different heights.
• the screw feeder by virtue of its rotation, can cause the pellets to crumble, with consequent increase of particulates in the fumes and at the same time emissions of pollutant substances.
• the aim of the present invention is to provide a device for dispensing pellets for a stove and a stove with such a device, that are capable of improving the known art in one or more of the abovementioned aspects.
• an object of the invention is to provide a device for dispensing pellets for a stove that makes it possible to dispense the fuel in a substantially constant manner.
• Another object of the invention is to provide a device for dispensing pellets for a stove that enables the stove to reduce emissions of pollutant substances with respect to similar, conventional devices.
• a further object of the invention is to provide a device for dispensing pellets for a stove that, when the device is actuated, makes it possible to prevent/reduce crumbling and the consequent emission of particulates in the fumes, with respect to similar, conventional devices.
• Another object of the invention is to provide a stove with a device for dispensing pellets that makes it possible to achieve the objects listed above.
• Another object of the present invention is to overcome the drawbacks of the known art in a manner different from any existing solutions.
• an object of the invention is to provide a device for dispensing pellets for a stove and a stove with such a device that are highly reliable, easy to implement, and at low cost.
• a stove fired by pellets according to the invention is generally designated by the reference numeral 10.
• the stove 10 comprises:
• the device 13 for dispensing pellets 12 comprises, considering its vertical axis of extension downward from above, in the following order:
• the spiral path 19 extends, for example, ideally along the outer surface of a truncated cone 22 with the smaller end face of such truncated cone 22 arranged below the larger end face of such truncated cone 22 and coinciding with the bottom 26 of the reservoir 18.
• the base 21 is arranged parallel to the smaller end face of the truncated cone 22, below the latter.
• the spiral path extends ideally along the outer surface of a vertically extending cylinder.
• the base 21 is arranged parallel to the lower end face of the cylinder, below the latter.
• the hopper 11 has a lower portion 27 with a frustum-like or pyramid-like profile for conveying the pellets 12 into the reservoir 18, adjacent to the upper end of the latter, but mechanically separated from it.
• spiral path 19 leads out, in an upper region, onto the chute 15.
• the vibration means 20 comprise:
• These elastic elements 25 are, for example, leaf springs, arranged transversely between the plane of arrangement of the bottom 26 of the reservoir 18 and the plane of arrangement of the base 21.
• the operation of the device 13 is the following.
• the electromagnet 24 is electrically powered with a single-phase AC voltage.
• the reservoir 18 is also subjected to a twisting movement.
• the pellets 12 are forced to shift and orient themselves, moving one step at a time, along the spiral path 19, so forming a continuous train of pellets 12.
• pellets 12 are transferred from the bottom 26 of the reservoir 18 to the chute 15 (arrow F in Figure 2 ) and from there to the brazier 14 (arrow Q of Figure 2 ).
• the effective value of the input voltage to the electromagnet 24 controls the frequency of the mechanical vibration and, therefore, the flow rate of pellets 12 to the brazier 14.
• the device 13 can comprise, by way of non-limiting example, an electronic and/or electromechanical device for modulating the amplitude and frequency of the electromagnet 24, such as for example a potentiometer and/or a variable turns-ratio transformer and/or an autotransformer (Variac), not shown in the figures, for modulating the effective value of the input voltage to the electromagnet 24 and in this manner also vary the flow rate of pellets 12 to the brazier 14, according to requirements.
• an electronic and/or electromechanical device for modulating the amplitude and frequency of the electromagnet 24, such as for example a potentiometer and/or a variable turns-ratio transformer and/or an autotransformer (Variac), not shown in the figures, for modulating the effective value of the input voltage to the electromagnet 24 and in this manner also vary the flow rate of pellets 12 to the brazier 14, according to requirements.
• Variac autotransformer
• the dispensing of the pellets 12 into the brazier 14 is uniform and constant.
• the invention fully achieves the intended aim and objects by providing a device for dispensing pellets for a stove that makes it possible to dispense the fuel in a substantially constant manner.
• a device for dispensing pellets for a stove has been provided that enables the stove to reduce emissions of pollutant substances with respect to similar, conventional devices.
• a device for dispensing pellets for a stove has been provided that, when the device is actuated, makes it possible to prevent/reduce crumbling, so limiting an increase in the particulates drawn into the fumes, with respect to similar, conventional devices.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Solid-Fuel Combustion (AREA)

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Citations (4)

• 2025
  • 2025-03-24 EP EP25165516.3A patent/EP4621290A1/fr active Pending

Patent Citations (4)

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