FR2577660A1 - Heat recoverer with water circulation for a fireplace - Google Patents

Abstract

Heat recoverer with water circulation for a fireplace with an open fire, forming a heat exchanger, placed in the fireplace, and which comprises an assembly of tubes for the circulation of water, comprising a horizontal tubeplate, forming a hearth-plate, and a vertical, or substantially vertical, tubeplate forming a baseplate, lower and upper manifolds, connected respectively to the vertical tubeplate, connecting the exchanger to a central heating installation with radiators, this heat recoverer being characterised in that it comprises a sleeve 18 enveloping the said vertical tubeplate 12, this sleeve comprising an upper opening 20 for the outlet of smoke into the smoke duct of the fireplace, and a frontal opening of frustoconical shape 22 in front of the horizontal tubeplate 10, above the hearth, so as to constitute a partial-vacuum draught column.

Description

1 2577660

  The present invention relates to a circulating heat recovery unit

  water culation for open fireplaces.

  Energy savings have led to renewed interest in chemi-

  Open fires using abundant and inexpensive fuels, particularly

  especially in rural areas, especially firewood. However, it is well known that these open fireplaces have poor efficiency, since they heat only by radiation, the heat energy of the hot gases resulting from combustion being evacuated through the flue of the chimney. We were therefore led to study systems making it possible to recover the calories thus lost. Generally, a conventional heat recovery unit is in the form of a heat exchanger, placed in the chimney, and

  which includes an assembly of water circulation tubes, made so as to

  titrate a horizontal tubular plate, forming a hearth plate, and a plate

  tubular vertical, or substantially vertical, forming the bottom plate of the che-

  mined, lower and upper collectors, connected respectively to the

  horizontal tube plate and the vertical tube plate, ensuring the

  heat exchanger cord to a conventional central heating system

diators.

  Such known systems effectively make it possible to improve the rendering

  heat from open fireplaces, recovering part of the heat

  contained in the products of combustion. However, experience shows that the thermal balance of the chimney remains poor, in particular due to the high temperature of the smoke gases discharged into the atmosphere (this temperature is of the order of 200 C in the flue, at the chimney outlet). In addition, these recuperators sometimes have a negative influence

  on the natural draft of the fireplace.

  The invention therefore proposes to bring improvements to the recovery

  heat generators of the type mentioned above.

  Consequently, this invention relates to a heat recovery unit of the type specified above, characterized in that it further comprises a jacket

  surrounding the vertical tubular plate of the recuperator, this jacket comprises

  both a frustoconical opening in front of the vertical tube plate,

  above the fireplace, and an upper opening in the flue, so

  to form a vacuum column improving the draft.

2.2577660

  According to the invention, the front part of said jacket, surmounting said frustoconical opening, consists of a cast iron plate oriented towards

  the room to be heated, in order to increase the heat energy radiated by the chimney

  undermined. Other features and advantages of this invention will become apparent from

  the description given below with reference to the attached drawing, which illustrates one

  exemplary embodiment devoid of any limiting character. In the drawing: - Figure 1 is a side elevational view of a recuperator according to the invention;

  - Figure 2 is a front elevational view of Figure 1.

  Referring to the drawing, we see that a calorie recuperator according to

  the invention is placed, as known, in a conventional open fire.

  It takes the form of a water circulation exchanger, consisting of an assembly of tubes comprising, on the one hand, a horizontal tubular plate 10, constituting the plate of the hearth of the chimney, and, on the other hand, a vertical tubular plate 12, forming the bottom plate of the chimney. Upper 14 and lower 16 collectors are respectively connected to the vertical plate 12 and to the horizontal plate 10, these collectors allowing the connection of the recuperator to a conventional central heating installation with radiators (not

shown).

  According to the invention, the bottom tubular plate 12 is provided with a jacket

  18 which completely envelops the tubes of this plate, leaving two openings

  tures: an upper opening 20, for evacuation in the flue

  combustion gases, and a front opening 22, of frustoconical section, au-

  above the horizontal tube plate. This jacket 18 constitutes, as clearly shown in FIG. 1, a vacuum draft column (venturi) which increases the contact surface between the hot combustion gases and the

  plate 12 tubes, while improving the draft of the chimney.

  According to the invention, this jacket 18 can be made of stainless steel sheet

  stainless, and preferably its front part 24 is made of cast iron, in order to improve the transmission by heat of radiation towards the interior of the room where the chimney is located. The visible face of the front plate 24 in cast iron can be provided with any ornamental pattern advantageously replacing a

fireplace plate.

  The tests carried out by the applicant have revealed the

3 l2577660vo

  improvements made by the recuperator according to the invention, compared to the systems

  known themes. The results of these tests are summarized in the following table Beginning of Heating End of Test (total duration 2 hours) Outside temperature 6 C 6 C Inside temperature 140 C 19 C Temperature of radiators 14 C 38 C Water temperature: 14 C 50 C Flue gas outlet temperature (point A) ........... 100 C

  The installation on which the recuperator according to the invention has been tested includes

  carried eight radiators, intended to heat a volume of 217 m. Note that the smoke outlet temperature is around 100 C, instead of 200 C

  in conventional recuperators.

  In addition to the remarkable increase in heating power, the device

  tif according to the invention improves the natural draft of the chimney,

  thanks to the venturi effect provided by the shape of the shirt 18.

  It remains to be understood that this invention is not limited to the example

  of embodiment described and shown, but that it encompasses all variants thereof.

Claims (3)

  1 - Water circulation heat recovery unit for an open fire, forming a heat exchanger, placed in the chimney, and which includes a   assembly of water circulation tubes, comprising a horizontal tube plate   zontale, forming hearth plate, and a vertical tubular plate, or sensitive-   vertical, forming bottom plate, lower and upper collectors,   connected respectively to the horizontal tube plate and to the tube plate   vertical space, ensuring the connection of the exchanger to a central heating installation with radiators, this heat recovery unit being characterized by   that it comprises a jacket (18) enveloping said vertical tubular plate   shim (12), this jacket comprising an upper opening (20) for the outlet of the fumes in the chimney flue, and a frustoconical front opening (22) in front of the horizontal tubular plate (10), above   of the hearth, so as to constitute a vacuum draft column.   2 - Heat recovery unit according to claim 1, characterized in that   that said jacket is made of stainless steel sheet.   3 - Heat recovery unit according to one of claims 1 or 2, charac-   terized in that the shirt (18) has a front portion (24) surmon-   both said opening (22) which consists of a cast iron plate oriented towards the part to be heated, in order to increase the calorific energy radiated towards this piece by the recuperator.