Open fireplace for living quarters or the like
United States Patent Fauser Apr. 1, 1975 [5 OPEN FIREPLACE FOR LIVING QUARTERS 3,190,282 6/1965 Bauer 126/121 x OR THE LIKE 3,762,391 10/1973 Andrews 126/121 [75] Inventor: Hans Fauser, Worb, Switzerland [73] Assignee: Superpart AG, Bern, Switzerland [22] Filed: Nov. 19, 1973 211 Appl. No 417,396  
 [30] Foreign Application Priority Data Dec. 6, 1972 Switzerland 17687/72 [52] US. Cl. 126/121, 126/131 [51] Int. Cl. F24b 7/00 [58] Field of Search 126/121,131  
 [56] References Cited UNITED STATES PATENTS 1.251916 l/1918 Parsons 126/131 1697635 H1929 Cornelius 126/121 2970590 2/1961 Fauscr 126/121 3180332 4/1965 Grushkin 126/121 Primary E.raminer-Willi am F. ODea Assistant Examiner-Peter D. Ferguson Attorney, Agent, or FirmWerner W. Kleeman [57] ABSTRACT An open fireplace for living quarters embodying a firebox, rear wall and flue or chimney as well as an air guiding system accommodated in the walls for entrapping or catching fresh air at a catch location arranged externally of the room and for heating this fresh air in at least one downdraft channel exposed to the thermal action of the firebox, the air infeed location of which is disposed at a higher location than its air outfeed location. At the air outfeed location of the at least one downdraft channel there is provided at least one updraft channel having an air outfeed location which opens into the room or the like.  
 6 Claims, 7 Drawing Figures WENTEDAPR&#39; 1 I915 OPEN FIREPLACE FOR LIVING QUARTERS OR THE LIKE BACKGROUND OF THE INVENTION The present invention relates to a new and improved construction of open fireplace for living areas or quarters encompassing a firebox, side walls, rear wall and flue or chimney as well an air guide system accommodated in the walls for catching fresh air at a catch or entrapment location arranged externally of the area or room and for heating this fresh air in at least one downdraft channel subjected to the thermal action of the firebox, and the air infeed location of which downdraft channel is higher situated than its air outlet or outfeed location.  
  With most of the heretofore known fireplaces the fresh air which is entrapped or caught externally of the area or room is only conducted through ascending channels, in other words exclusively follows the natural warm air currents.  
  The guiding of the air of the initially discussed fireplace differs from this just mentioned guiding of the air in an advantageous manner in that the air in the downdraft channel must flow opposite to the warm air currents or upcurrents in the room, so that only in the event of negative pressure in the heated rooms the air caught externally of such room flows through the air guide system into the room. With the windows and doors closed, that is to say, during normal conditions, there continuously prevails in the heated room owing to the outflowing flue gases such a negative pressure which is continuously compensated by means of the air which inflows from the outside through the air guide system. The thus inflowing fresh air is heated as opposed to arriving in the normal manner in a cold state through windows and door cracks in the room. Now since the movement ofthe air in the downdraft channel occurs from the top toward the bottom, in other words in a direction oposing the natural flow tendency of the hot air, a pronounced turbulence prevails in such compartments and thus a very intensive heating-up of all of the air particles occurs.  
  There is advantageously provided a fresh air catch location which is disposed externally of the heated room an ascending channel section which leads to the air inlet location of the downdraft channel. Now such open fireplaces are increasingly more frequently not used as the actual permanent heating system or element, rather more often as an auxiliary unit in conjunction with generally central heating systems, so that they are assigned the function ofincreasing the room termperature during the normal non-heating periods, especially in the spring and fall. During these transition periods it oftentimes happens that the room or area is not so tightly sealed that a sufficient negative pressure can build-up therein in order to suck-up fresh air through the downdraft channel. Hence, there remains, just as is the case for the simple open fireplaces, only the radiant heat in the room or area to which there is additionally continuously infed cold air, for instance through open windows. The advantages of the previously mentioned fireplaces are then lost, in fact when encountering these conditions they are even less effective than the previously mentionedfireplaces equipped with a simple rising or updraft channel. which at least convey from the outside hot air due to the natural warm air current or can circulate such within the area or room.  
 LII  
 SUMMARY OF THE INVENTION Hence, it is a primary object of the present invention to provide an improved construction of fireplace which is not associated with the aforementioned drawbacks and limitations of the prior art proposals.  
  Another and more specific object of the present invention aims at the provision of a new and improved construction of open fireplace which possesses the advantages of the previously mentioned fireplaces with regard to their good utilization of thermal energy both duringfavorable operating conditions as well as also during the aforementioned unfavorable operating conditions.  
  It has now been surprisingly found that the effectiveness of the previously mentioned open fireplace can not only be considerably increased during the aforementioned favorable operating conditions, rather can be rendered extremely effective also for the abovementioned unfavorable conditions if the air outlet location of the downdraft channel is connected with an updraft channel which opens at its upper end into the room.  
  Hence, for the purpose of realizing the objectives of the invention, the inventive open fireplace of the previously mentioned type is manifested by the features that at the air outlet location of the at least one downdraft channel there is provided at least one updraft channel with an air outlet opening which opens into the area or room.  
  Whereas, with the aforementioned favorable operating conditions this ascending or updraft channel is capable of bringing about an acceleration of the air flow in the room. during the unfavorable operating conditions it initially receives a relatively small quantity of hot air at its lower end which then ascends therein and thus generates a negative pressure at the lower end of the downdraft channel which at that location sufficiently opposes the warm air current therein which acts in oppostion to the flow, in order to bring about a flow in the room.  
  According to a particularly preferred constructional manifestation of the invention, the ascending or updraft channel can be equipped with additional air inlet locations which lead into the room, and which when suitably arranged, for instance in the manner of a Venturi nozzle, bring about a sucking-up of the air in the room into the updraft channel when there prevails in the updraft channel a relatively rapid flow. If such flow cannot prevail from the downdraft or downflow channel, because the warm air currents therein act too strongly, and because no negative pressure prevails in the room (for instance with the windows extensively opened), then at leastin the updraft channel there can be built-up an air current or flow which circulates the air in the room and heats such up. This is particularly then the case when the air inlet location of the downdraft channel is connected with the fresh air catch loca tion by means of a channel which ascends from the location of the fresh air catch location, so that a certain stagnation of the flow in the downdraft channel can be effective and at least it does not pump air out of the room towards the outside or surroundings.  
  Additionally, there also can be provided that the combustion air leading to the firebox already at the catch location or at the ascending portion of the channel system is separated or separately seized from the fresh air which is to be heated, so that only the air in the downdraft channel which serves to heat the room is heated.  
  In the case of rooms which are strongly ventilated, where seizing or entrapment of the fresh air externally of the heated living area or quarters does not respond, the fireplace of this development can be rendered useful in that there is provided at the updraft channel at least one lower connection opening in the heated room or area, whereby then colder air flows in at the lower opening to such updraft channel and after being heated again flows out through the upper openings. This can also serve for admixing the room air with the heated-up fresh air.  
  It is contemplated for the practical realization of the invention that the actual components of the fireplace are formed of pre-fabricated self-supporting shaped bricks which collectively provide a load-carrying construction, and without any additional expedients also can form supports for the smoke channel or flue.  
 BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:  
  FIG. 1 is a front view of a first embodiment of fireplace designed according to the teachings of the present invention;  
  FIG. 2 is a side view of the fireplace depicted in FIG. I;  
  FIG. 3 is a vertical sectional view of the fireplace depicted in FIG. 2, taken substantially along the line III- --III thereof;  
  FIG. 4 is a vertical sectional view of the fireplace depicted in FIG. 1, taken substantially along the line IV-IV thereof;  
  FIG. 5 is a perspective view of the different structural components, partially in section, partly shown exploded, partly shown assembled, of the fireplace depicted in FIG. 1;  
  FIG. 6 is a side view, similar to the showing of FIG. 2, of a second embodiment of fireplace; and  
  FIG. 7 is a sectional view of the fireplace depicted in FIG 6, taken substantially along the line VIIVII thereof.  
 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now the drawings, the exemplary embodiment of open fireplace for living quarters or areas, typically a room, as depicted in FIGS. l5 will be understood to comprise a base or mounting plate 1, a floor plate 2, two side portions 3 and 4, a closure plate 5, and a smoke collecting element or flue 6 arranged thereabove. These six elements or components at the same time form a supporting frame for the non-illustrated smoke withdrawal channel. This fireplace furthermore possesses two fire bridges or blocks 8 and 9, a partition wall 7 composed of two plates, a firebox rear wall 10 formed of heat conducting or transmitting material. a cover 11 for the ash chute and three regulating flaps or flap valves 12, 13 andl4.  
  Upon mounting the floor plate 2 at the base plate 1 there are formed two symmetrically arranged air guide channels 15 and 16 by means of which the fresh air entrapped or collected at the rear at location 17 is guided directly beneath the fire, in that such flows-out from both sides directly beneath the fire or refractory blocks 8 and 9, as best seen by referring to FIGS. 3 and 5. Since the fire bridges 8 and 9 are markedly heated by the burning mat&#39;erial reposed thereon, the infed air is heated before it reaches the firebox 10a, and in this regard attention is directed to the broken lines of FIG. 5. The quantity of such combustion air which is referred to as primary air can be randomly dosed or completely throttled by means of the regulating flap valve 12.  
  Between the rear wall 10 of the firebox 10a and the partition wall 7 there is arranged the downdraft or downfiow channel 7 which is connected with the fresh air catch means 17 by means of the ascending channel 17 located behind the partition wall 7 and by means of the connection channels 70, is connected with the updraft or riser channels 3, 4&#39; accommodated in the side walls 3 and 4. The channels 3&#39; and 4&#39;, open via the upper lateral openings 3 and 4&#34; respectively with the heated room or area.  
  A portion of the fresh air which flows in from the outside is therefore conducted through this system of channels. By heat transfer from the firebox this air is thus heated and therefore conducted in a heated condition through the openings 3&#34;, 4&#34; into the room or area.  
  The flow through the downdraft or downflow channel 7&#39; occurs from the top towards the bottom, i.e. from the higher situated air infeed location 7a to the air outfeed location 712. The natural flow of the warm air current or upcurrent opposes this movement of the air in the channel 7, whereas a negative pressure in the room (owing to the operation of the fireplace) conveys this flow. Also this flow can be dosed or regulated by the flap 14. Now if an insufficient negative pressure exists in the room or area this flow would die out if there were not present a flow through the updraft channels 3&#39;, 4&#39; owing to the warm air currents.  
  Since the movement of the air in the downdraft channel 7 occurs from the top towards the bottom, in other words takes place in a direction which opposes the natural flow tendency of the hot air, there prevails therein a pronounced turbulence and thus a very intensive heating up of all of the air particles.  
  Additionally, since the air which is heated in this manner is withdrawn through the updraft channels 3, 4 also then from the downdraft channel 7&#39; when there does not exist any sufficient negative pressure in the room or the like for this purpose, there practically is always insured for a good heating efficiency.  
  Since the movement of the air in the channels, with such type arrangment, no longer is dependent upon the negative pressure of the heated room, this movement of the hot air also can exist even if all of the windows and doors of the room are not closed. This constitutes a decisive advantage.  
  If the fireplace were to exist without the ascending or updraft channels 3, 4, as such was previously the case with prior art systems, and if for instance a window is opened, then the negative pressure in the room is immediately balanced out by the direct inflow of air and the circulation of air in the channels either stops or is reversed. The infeed of hot air to the room, which under such circumstances would be then particularly useful, would be suppressed. Quite to the contrary. it can happen that air is pumped off via the channels, so that the previously attained storage of heat in the mate rial of the fireplace or firebox is suppressed. As previ ously explained, with the fireplace of this invention such normally is not to be feared.  
  However, situations can arise in which the direct entrainment of fresh air externally of the room or area, for instance owing to wind conditions, can not be carried out. In such instances there can be employed the second embodiment of fireplace, which otherwise operates in the same manner, and as shown in FIGS. 6 and 7 for the purpose of bringing about a circulation of hot air in the room or area.  
  It is to be understood that those components of the embodiment depicted in FIGS. 6 and 7 which correspond with the fireplace construction discussed above in conjunction with FIGS. 1 5, and this is so with the exception of the particular lateral or side openings of the channels 3&#39; and 4&#39;, have been generally conveniently designated with the same reference characters.  
  Hence, also in this case there is provided the base plate 1, the floor plate 2, the side walls 3 and 4, the closure plate 5 and the smoke collector or flue 6.  
  Furthermore, also with this variant embodiment the remaining construction of the fireplace as depicted in FIGS. 1-5 has been found to be useful, but since there is only to be considered the coaction between the fresh hot air possibly arriving from the non-visible downdraft channel 7 through the channels 70, 70&#39; and the room air which is circulated in the room by the channels 3&#39; and 4, and in order to simplify the illustration and discussion not all of these other components have been shown in the illustration of this embodiment.  
  The channel 3 has an inclined opening 30 which opens from below into the room, whereas a corresponding opening 40 is provided at the channel 4&#39;.  
  These openings, ifdesired, can be closed by the flaps or flap valves 31 and 41 respectively, which also can be advantageously used for closing off the fresh air-hot air infeed. By appropriately setting the flaps, it is possible to control the ratio of fresh air and recirculated or return air.  
  For instance. the flaps can shut-off the entire infeed of fresh air at the start of the heating operation, so that there prevail ascending or updraft currents in the channels 3. 4&#39; which are brought about by the warm air currents. which then if desired, also can be used for bringing about a stagnating fresh air infeed, if the flaps 31, 4] are appropriately regulated. Thus, in the case of colder conditions there can be prevented that with the walls of the fireplace still cold there will be already introduced at such time fresh air. whereby however it is nonetheless possible to utilize the gradually ascending temperature of the fireplace material for heating the recirculating air.  
  While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims. Accordingly,  
 What is claimed is:  
  1. An open fireplace for living areas or rooms or the like, comprising a firebox, side walls, rear wall and flue including an air guide system accommodated in the walls thereof for collecting and heating fresh air, the air guide system including a fresh air catch arranged externally of the room, a downdraft channel which communicates with the air catch and which is subjected to the thermal action of the firebox, the downdraft channel having an air infeed which is situated higher than its air outfeed, an ascending channel for connecting the fresh air catch with the air infeed of the downdraft channel and an updraft channel which is subjected to the thermal action of the firebox, saicl updraft channel having an air inlet communicating with the downdraft channel air outfeed and an air outlet communicating with the room.  
  2. The open fireplace as defined in claim 1, wherein the downdraft channel is at least primarily arranged at the rear wall and a respective updraft channel connecting therewith is provided in each side wall.  
  3. The open fireplace as defined in claim 1 wherein said fresh air catch is positioned below the downdraft channel air infeed and said updraft channel room outlet is positioned above the downdraft channel air outfeed whereby fresh air is serially conducted upwardly. downwardly and then upwardly through the air guide system before entering the room.  
  4. An open fireplace for living areas or rooms or the like, comprising a firebox, side walls, rear wall and flue including an air guide system accommodated in the walls thereof for collecting and heating fresh air, the air guide system including a fresh air catch arranged externally of the room, a downdraft channel which communicates with the air catch and which is subjected to the thermal action of the firebox, the downdraft channel having an air infeed which is situated higher than its air outfeed, an ascending channel for connecting the fresh air catch with the air infeed of the downdraft channel, and an updraft channel having an air inlet which communicates with the downdraft channel air outfeed, said updraft channel being further provided with an air inlet and an air outlet each of which communicates with the room.  
  5. The open fireplace as defined in claim 4, further including control means in order to determine the quantity of air arriving through the different air inlet locations in the updraft channel.  
 6. The open fireplace as defined in claim 5, wherein said control means comprises at least one flap member. l =l