FR2788333A1 - Hot secondary air injection into wood furnace, comprise a central vertical tube assembly with a secondary air intake assembly - Google Patents

Abstract

The device for injecting secondary hot air into wood furnace comprises a central vertical tube (1) having an independent secondary air intake in the lower part. The upper part of the tube has a cowl (2) which channels the air rising from the bottom to the top. The central tube can be housed in a larger diameter tube (3) to form a space in which the secondary air flows from the top to the bottom allowing the mixing of this air with the burnt gases leaving the furnace. The mixing is facilitated by a chicane (4).

Description

The present invention relates to a device for introducing air

  hot nine in the heart of a wood fuel fireplace, sawdust chips and thus bring oxygen at very high temperature

  to ignite unburnt gases and cause post-combustion

  tion to reduce CO and increase CO 2 (CO + 0 = CO 2)

  The traditional operation of these devices without this dis-

  positive does not lower the CO sufficiently towards 0 by one

  in a natural way, whatever the walking regime and more precisely

  when idling when the primary air valve is closed.

  - The device according to the invention overcomes this major drawback. According to a first characteristic, it in fact comprises a vertical central chimney taking in secondary air at the bottom, outside and independently of the valve regulating the entry of primary air. To be brought to very high temperature - an essential and essential condition for igniting unburnt gases, the secondary air flows upward.

  naturally the very heart of the hearth, source of high temperature

  ture. It is thus heated and directed into the hearth itself, mixed

  to unburnt gases which causes post-combustion.

  - According to particular embodiments: The central chimney can be constituted by a tube (FIG. 1) at the top of which a cap returns the flow of hot air down to the very heart of the hearth where it is moreover drawn in the

  chimney draft causing post-combustion.

  - The vertical central chimney can be supplemented by a second tube of a larger diameter encircling the first tube on a descending part to direct and mix thanks

  to a deflector the flow of secondary air heated with imbricated gases

  -2- les and there also cause the generative post-combustion

CO very close to Z6ro.

  The central chimney with single or double tube is maintained in the vertical position over its entire height, under the - hearth, through the grate and in the hearth itself. The accompanying drawings illustrate the invention: FIGS. 1 and 2 show in section the device of the invention with a central chimney made with a tube capped with a hat at the top which directs towards

  - the bottom in the hearth the secondary air flow.

  Figs. 3 and 4 show in section the device of the invention with a vertical central chimney housed in a second tube of a larger diameter which directs the flow of secondary air into the space created by the difference - from the two diameters towards the bottom where a deflector diverts it

  at the very heart of the hearth and mixing it with the imbedded gases.

  These two devices, single or double channel are a function of the height of the fireplace itself, the double channel being reserved

high homes.

  - These different figures represent the central chèm2nr4e

  crossing the grid at its base to take second air

  air outside the device independently of the valve

  primary air. These different figures also represent

  lie the side baffle forcing the fumes to come out

  - slightly above the grid to avoid the flare-

  entire fuel stored in the fireplace.

  These devices thus significantly improve the performance of the device by causing a real post- '3-

-combustion and reduce C 0.

  The device according to the invention is particularly intended for

  born in wood stoves and boilers, sawdust and shavings

domestic and semi-industrial.

  The dimensions of the devices and their calorific value can be identical to what is traditionally done, -4--

Claims (5)

-. R E V E N D I C A T I O N S.-   1 Device to increase efficiency and reduce emissions   C O sions of a wood-burning stove or boiler, sawn   ures or chips characterized in that it comprises a tube   vertical central unit (1) comprising a secondary air inlet   daire independent at the bottom and a hat (2) at the top after crossing the hearth   channeling secondary air from bottom to top.   2 Device according to claim 1 characterized in that the central tube can itself be housed in a larger diameter tube (3) thus creating a space between the two tubes allowing the circulation of secondary air from top to bottom allowing the more intimate mixture of this secondary air with the unburned gases leaving the hearth, This mixture being facilitated by the presence of a baffle (4).   3 Device according to claims 1 and 2 characterized   in that the two tubes 1 and 3 pass vertically through the heart of the very high heat source hearth allowing   optimum secondary air rise for post-   effective combustion and maximum C O reduction.   4 Device according to claim 3 characterized in that the secondary air stream brought to very high temperature is well directed downward, phenomenon facilitated in this by the presence of a side baffle (5) slightly above the grid to force the smoke down   before joining the chimney and thus avoid the fire   total fuel stored in the fireplace.   -5) Device according to claim 4 characterized in that this secondary air injection is done naturally without mechanical or electrical assistance (fan, turbo etc ...) whatever the operating regime and especially when the fireplace is stopped when the primary air valve is closed since   only secondary air continues to be drawn in.