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Modular fireplace and chimney

Modular fireplace and chimney description/claims

The contents of Provisional Application U.S. Ser. No. 60/898,852 filed Feb. 1, 2007, which the present application is based and benefit claimed under 35 U.S.C. §119(e), is herein incorporated by reference.

1. Field of the Invention

The present invention relates to a modular fireplace and chimney. More particularly, the present invention relates to a set of modular concrete units laid in consecutive courses at the job site to form a solid masonry fireplace firebox and a solid masonry smoke chamber and chimney.

2. Background Art

The construction of the traditional masonry fireplace has traditionally been accomplished by skilled masons building the fireplace and chimney structure brick by brick according to patterns and dimensions handed down from generation of craftsman to craftsman. Considering the scarcity of skilled labor required for the layout and construction of a masonry fireplace using those established methods, as well as the large quantity and cost of time and masonry materials consumed, other methods of building fireplaces have been sought by builders.

Many products have been introduced to shorten the time of construction, lower the cost, and to obtain a reasonably serviceable fireplace. In fact many fireplaces are built “vent-free” to avoid the cost and all of the other negatives associated with the new methods of building a naturally drafted fireplace. This widespread use of the vent free variety of fireplace has contributed to a whole host of indoor air quality problems not present with the use of naturally drafted fireplaces. However, none of the new methods have brought all of the necessary attributes together to reach the full function and reliability of a fireplace built the old way.

By category, fireplace product types being utilized today fall into several distinct categories 1-4 below:

First, the metal insert fireplace type: The metal inserts do not attempt to approximate the masonry fireplace except in the shape of the firebox and in their utilization of a thin applique of refractory brick for a lining. The firebox itself is made of a double layer of sheet metal, and the flue is a double walled metal flue suspended within a framed chimney chase. Weaknesses of this type include a tendency to wear out or burn out, and a tendency for the chimney itself to be susceptible to leakage because of the frame construction of the chimney chase itself. Also, the use of a metal flue contained within a wood framed chimney chase raises questions of the use of hot metal flue materials close to the wood structure with only a small air space separating the two. Finally, the framed chimney chase itself is susceptible to damage by high wind, and is susceptible to leakage regardless of the exterior cladding used to sheath the chimney. Most often the exterior chimney cladding is either clapboard siding, stucco, or brick veneer applied over wood or metal framing. The flue and damper in this type fireplace are far less durable than those in a traditional clay flue lined fireplace and chimney.

Second are the proprietary masonry fireplace systems, including those made of various standard, lightweight, and aerated concrete materials. These fireplaces exceed the metal fireplaces in quality and authenticity by utilizing masonry units for the area of the firebox, and therefore are capable of storing heat, and providing a longer lasting structure to which can be added a thin-set refractory lining. This group of fireplace systems commonly utilizes one of two chimney flue types, often interchangeably: a double lined metal flue identical to the metal fireplace, or a stacked flue made of proprietary masonry blocks glued or mortared together to form only the flue liner. In either case however, the chimney liner still passes through a wood framed chimney, or requires traditional masonry methods to form the chimney. In the case of framed chases, the same problems exist with a high susceptibility to leakage, wind damage, and difficulty in maintenance regardless of the veneer or cladding used on the framed chimney chase structure. So, these fireplace chimneys are still hybrid systems that combine a masonry or metal flue liner within a framed chimney. Most often the exterior chimney cladding is either clapboard siding, stucco, or brick veneer applied over wood or metal framing, leaving the chimney highly susceptible to deterioration and water intrusion regardless of the exterior cladding used on the chimney. While the flue and damper in this type of fireplace begin to approach the durability and functionality of a traditional masonry fireplace and chimney, this type of fireplace and chimney still fails to complete the entire picture since it relies on a framed structure to provide the chase for the flue liner, and therefore does not offer the true masonry chimney mass found in a masonry chimney of traditional construction.

Third are the vent free fireplaces. They provide a flame proof enclosure of metal or masonry, with no provision for the conveyance of flue gasses out of the structure. Their use is limited to specially designed gas log appliances that emit relatively low levels of carbon monoxide.

Fourth are the mechanically assisted ventilated fireplaces which rely on a fan and duct to evacuate combustion gasses, and often utilize far smaller flue diameters than naturally drafted fireplaces utilize. Ducting of exhaust may be either vertical or horizontal out of the structure.

In addition to the types of manufactured products and systems described above, some fireplaces are still constructed brick by brick the traditional way. These traditional fireplaces are the true, naturally drafted fireplaces with refractory brick lining, solid masonry firebox and solid masonry chimney, usually made of solid brick construction. They provide complete evacuation of the combustion gasses through a large vertical lined or unlined flue. They also provide a durable, weather resistant solid masonry chimney which may be flashed properly, and which is not susceptible to leakage and channeling of water into the structure. This is the most versatile, traditional, and proven type of fireplace, and the most difficult and costly to replicate in all of its features.

Therefore, it is a general object of the present invention to provide a ready-to-assemble, modular masonry fireplace and chimney system that is capable of yielding a solid masonry fire box as well as a solid masonry chimney without requiring the normal brick-by-brick construction, and which is capable of incorporating several widely available and proven non-proprietary components, including a clay flue liner which comes in standard sizes, as well as a cast iron damper, both of which are characteristic of the true brick fireplace.

Another object of the present invention is to provide a modular masonry fireplace and chimney system whose components can be manufactured using existing concrete block forming technology and materials so that the invention may be widely manufactured in the existing industrial setting and that it shall be versatile in design to provide for the introduction of longitudinal steel reinforcing as needed based on local building codes to strengthen the chimney structure against the effects of high winds, seismic loads, and live loads imposed during construction.

Yet another object of the present invention is to provide a system for building a fireplace that utilizes a minimum number of special casting shapes to make its manufacture feasible and economical.

The fireplace and chimney of the present invention are made of specially formed stacked modular concrete units laid in prescribed configurations in horizontal masonry courses, and specifically designed so a traditional clay flue liner may be inserted into the modular chimney as it is being erected. The sections making up the fireplace and chimney are the firebox, the damper level, the structural shelf level, the tapered smoke chamber level, and finally, the chimney itself.

In addition to providing a ready-to-assemble fireplace fire box, the present invention utilizes a chimney system built of easy-to-construct modular concrete masonry units. The result is a solid masonry fireplace and a solid masonry chimney which is designed to receive a traditional clay flue liner appropriately sized to match the fireplace size. The chimney is erected with distinctive modular concrete masonry unit shapes laid in horizontal masonry courses, and is designed to have a clay flue liner inserted in segments. Self-gauging alignment lugs integrally cast into the inside of the modular chimney units assure proper clay flue liner alignment.

The modular chimney units are also fashioned so they may accommodate more than one flue liner size by making minor field modifications, specifically by breaking off a portion of the alignment lugs to make room to receive the next larger clay flue liner size. This ability to accommodate a variety of flue sizes within one size modular chimney unit while providing an air space between the flue liner and the chimney wall are distinctive features of the invention. The fact that the invention provides both a flue and a chimney structure is also a distinctive feature compared to other manufactured items that provide only a flue liner, and depend on the user to construct the chimney structure out of other materials.

• Provisional Patent
• Utility Patent

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