Title:
MODULAR FIREPLACE AND CHIMNEY
Kind Code:
A1


Abstract:
The fireplace and chimney is provided made of specially formed stacked modular concrete units laid with several modular concrete masonry units 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 the chimney to form a naturally drafted masonry fireplace assembly.



Inventors:
Mullin, Rick (Charleston, SC, US)
Application Number:
12/023681
Publication Date:
08/07/2008
Filing Date:
01/31/2008
Primary Class:
Other Classes:
52/218
International Classes:
F24B1/18; F24B7/00
View Patent Images:
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Primary Examiner:
PEYTON, DESMOND C
Attorney, Agent or Firm:
Craig, Killough B. (P. O. DRAWER H, CHARLESTON, SC, 29402, US)
Claims:
What is claimed is:

1. A modular fireplace and chimney having multiple sections including a firebox, a damper level, a structural shelf level, a tapered smoke chamber level and a chimney comprising: (a) firebox having several vertical courses of formed pre-cast concrete masonry units forming a pair of sides and a back, (b) a damper level including a damper and at least one reinforced concrete lintel situated horizontally on said firebox sides to bridge across the top of said firebox opening, thereby providing a bearing surface for the front damper flange and additional masonry courses; (c) a structural shelf level comprising a generally rectangular reinforced concrete shelf with hole there through to allow the passage of flue gasses from said firebox into said smoke chamber and chimney above said shelf level, and to provide structural support for the overlying chimney courses; (d) a tapered smoke chamber level having a tapered smoke chamber, and (e) a chimney comprising a plurality of concrete masonry chimney members, with at least one masonry chimney member per masonry course, said masonry courses forming a structural masonry chimney shaft, bearing on the flat surface of said reinforced concrete shelf and a chimney flue liner.

2. The fireplace and chimney according to claim 1 wherein said firebox further comprises an inverted wedge-shaped cast-in-place concrete masonry member whose shape and function is to form a smoke shelf on said firebox back.

3. The fireplace and chimney according to claim 1 wherein said firebox further comprises a refractory brick lining.

4. The fireplace and chimney according to claim 1 wherein said tapered smoke chamber level further comprises a tapered smoke chamber liner having two halves, each comprised of pieces of clay flue liner cut on an angle to fit together within the interior cavity of the courses of said tapered smoke chamber.

5. The fireplace and chimney according to claim 1 wherein said masonry chimney members include two sets of opposing integral concrete spacer lugs on the interior surfaces thereof to provide proper alignment for the installation of sections of said chimney flue liner which are slipped into the available space, and are vertically aligned by the concrete spacer lugs resulting in a continuous open flue passage for the exhaust gasses from the smoke chamber to the point of exit at the top of the chimney.

6. The fireplace and chimney according to claim 5 wherein said chimney members comprises two opposing concrete spacer lugs and each lug includes one or more cast-in score marks to serve as pre-gauged break points, said spacer lugs being graduated in their width at least once so as to introduce a stress riser at the inside corner of the integral lug casting to break off to accommodate different sized flue liners.

7. The fireplace and chimney according to claim 6 wherein said chimney flue liner is in casual contact with said spacer lugs, there being an open air space between an inner wall of said masonry chimney members and the outer surface of the chimney flue liner.

8. A modular fireplace and chimney having multiple sections including a firebox, a damper level, a structural shelf level, a tapered smoke chamber level and a chimney comprising: (a) firebox having several vertical courses of formed pre-cast concrete masonry units forming a pair of sides and a back, (b) a damper level including a damper and at least one reinforced concrete lintel situated horizontally on said firebox sides to bridge across the top of said firebox opening, thereby providing a bearing surface for the front damper flange and additional masonry courses; (c) a structural shelf level comprising a generally rectangular reinforced concrete shelf with hole there through to allow the passage of flue gasses from said firebox into said smoke chamber and chimney above said shelf level, and to provide structural support for the overlying chimney courses; (d) a tapered smoke chamber level having a tapered smoke chamber, and (e) a chimney comprising a plurality of concrete masonry chimney members, with at least one masonry chimney member per masonry course, said masonry courses forming a structural masonry chimney shaft, bearing on the flat surface of said reinforced concrete shelf, said chimney further comprising said masonry chimney member includes two sets of opposing integral concrete spacer lugs on the interior surface thereof to provide proper alignment for the installation of sections of said chimney flue liner which are slipped into the available space, and are vertically aligned by the concrete spacer lugs resulting in a continuous open flue passage for the exhaust gasses from the smoke chamber to the point of exit at the top of the chimney.

9. The fireplace and chimney according to claim 8 wherein said chimney member comprises two opposing concrete spacer lugs and each lug includes one or more cast-in score marks to serve as pre-gauged break points, said spacer lugs being graduated in their width at least once so as to introduce a stress riser at the inside corner of the integral lug casting to break off to accommodate different sized flue liners.

10. The fireplace and chimney according to claim 9 wherein said chimney flue liner is in casual contact with said spacer lugs, there being an open air space between an inner wall of said masonry chimney member and the outer surface of the chimney flue liner.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

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.

BACKGROUND OF THE INVENTION

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.

SUMMARY OF THE INVENTION

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.

The invention also utilizes the same kind of cast iron damper used commonly in the true brick fireplace. So, the invention simplifies the masonry construction needed to build the firebox and chimney by eliminating brick-by-brick construction while still providing masonry mass, and utilizing the readily available damper and flue liner components that go into a real brick fireplace.

The invention utilizes only six distinctive casting shapes in its current embodiment, offering a major advantage over more complex systems that are reliant upon a larger number of casting shapes and configurations. Of the six castings used in the invention four of them (Parts #1,#2,#3, and #6) are simple co-planer extrusions, able to be made on existing concrete block casting beds that already exist where regular concrete blocks are manufactured using automated equipment. These four parts are the parts that are used in greatest number in the construction of the invention. The remaining two parts (Parts #4 and #5) while not designed to be made in the automated block plant setting, are readily made as precast parts in the pre-cast concrete manufacturing setting.

Other objects, features and advantages of this invention will be apparent from the following detailed description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

FIG. 1 is a front view of the modular concrete fireplace and chimney of the present invention showing the masonry courses making up the firebox level, damper/smoke shelf level, structural shelf level, tapered smoke chamber level, and the chimney level;

FIG. 2 is a cut away front view of the modular concrete fireplace and chimney of the present invention showing the masonry courses making up the firebox level, damper/smoke shelf level, structural shelf level, tapered smoke chamber level, and the chimney level;

FIG. 3 is a cut away left side view of the modular concrete fireplace and chimney of the present invention showing the masonry courses making up the firebox level, damper/smoke shelf level, structural shelf level, tapered smoke chamber level, and the chimney level;

FIG. 4 is a plan view of the first two courses of the firebox of the present invention as shown in FIG. 2 and FIG. 3 at levels A and B showing the firebox side castings and back castings;

FIG. 5 is a plan view of the firebox of the present invention shown in FIG. 2 and FIG. 3 at the top of level C showing the firebox side castings and back castings as well as the cast smoke shelf;

FIG. 6 is a plan view of the firebox of the present invention shown in FIG. 2 and FIG. 3 at the top of level D showing the firebox side castings and back castings as well as the cast smoke shelf;

FIG. 7 is a plan view of the firebox of the present invention shown in FIG. 2 and FIG. 3 at the top of level E showing the left and right firebox side castings, the back castings, the cast smoke shelf, and the structural lintel with the damper bearing on this course of masonry;

FIG. 8 is a plan view of the damper level of the present invention shown in FIG. 2 and FIG. 3 at the top of level F.

FIG. 9 is a detailed plan view of a damper for use in the present invention as shown in FIG. 7;

FIG. 10 is a plan view of the firebox castings of levels A&B showing a fire brick lining in the firebox;

FIG. 11 is a plan view of the structural shelf of level G showing a shelf of equal halves;

FIG. 12 is a side view showing the cast smoke shelf wedge at levels C, D and E;

FIG. 13 is a plan view of the firebox back castings of FIG. 2 and FIG. 3 showing the cast smoke shelf wedge;

FIG. 14 is a top view of the smoke chamber configuration at levels H and I;

FIG. 15 is a top view of the cast masonry block with a portion cut away for use in the smoke chamber of FIG. 14;

FIG. 16 is a top view of the chimney assembly at levels J1-J6 of FIG. 2 and FIG. 3;

FIG. 17 is a plan view of the intact modular concrete unit used in level J1-J6 of FIG. 2 and FIG. 3 and shown in detail in FIG. 16;

FIG. 18 is a detailed view of the smoke chamber lining at levels H and I;

FIG. 19 is another embodiment of level F levels A and B of FIG. 2 and FIG. 3 showing how a larger fireplace width may easily be achieved by adding a spacer block in the back firebox wall;

FIG. 20 illustrates another embodiment of the chimney at Levels J1-J6 with the flue liner within a modular chimney block designed to be clad with brick.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

Referring now to FIG. 1, there is shown a front view of the modular fireplace and chimney 10 of the present invention showing the various sections making up the masonry courses. The sections include the firebox, damper level 30, structural shelf level 40, tapered smoke chamber level 50, and the chimney 60. The modular fireplace and chimney 10 is made of specially formed modular concrete members laid in prescribed configurations in horizontal masonry courses.

Turning first to the firebox, there is shown in FIG. 2 and FIG. 3, the firebox 20 composed of several vertical courses of specially formed pre-cast concrete masonry units for its sides, which when laid together in masonry courses form the left and right sides of the firebox ready to accept a thin-set refractory brick lining. The masonry courses of the firebox 20 are shown in FIG. 2 and FIG. 3 as levels A through E.

Details of the composition of masonry courses A and B are shown in FIG. 4 and include a left firebox side casting 1, a right firebox side casting 1, a straight firebox back 2, forward right and left sidewalls 2 and lintel supports 3. As noted the casting for the forward sidewalls and the straight firebox back may be the same size. Castings for parts 1 and 2 are simple co-planer extrusions, able to be made on existing concrete block casting beds that already exist where regular concrete blocks are manufactured. Castings 1 and 2, although of different sizes, are four sided with two adjacent sides being longer than the other two side so that when placed in a layer as shown in FIG. 4 the castings will form the appropriate angle to form the firebox. Lintel supports 3 are normally rectangular, long side of which is the length of the short side of forward sidewalls 2. Reinforcing bars 12 are placed at pertinent locations throughout the courses. Reinforcing wire is placed in the mortar between every two courses.

As shown in FIG. 5 the masonry course of the firebox 20 at level C shows the left firebox side casting 1, right firebox side casting 1, forward right and left sidewalls 2, and lintel supports 3 and smoke shelf 7 (see details in FIG. 12 and FIG. 13). The masonry course shown in FIG. 6 is a plan view of the firebox 20 shown in FIG. 3 at level D showing the left firebox side casting 1, right firebox side casting 1, forward right and left sidewalls 2, lintel supports 3 and smoke shelf 7.

One or several reinforced concrete lintel pieces 4 are situated horizontally above the firebox 20 and bear on the firebox sides below level E to bridge across the top of the opening in firebox 20, and provide a bearing surface for the front flange of damper 8 and all additional courses of masonry above. FIG. 7 at level E shows the left firebox side casting 1, the right firebox side casting 1, forward right and left sidewalls 2, and rectangular structural lintel 4, which is the thickness of level E. The narrow ends of lintel 4 on each side of the fire box 20 bear on the lintel supports 3 in the masonry course below.

The next section, the damper level 30, comprises one masonry course, level F. Level F, as shown in FIG. 8, has left firebox side casting 1, the right firebox side casting 1, forward right and left sidewalls 2, and the structural lintel 4 and further includes an iron damper 8 with its flanges bearing on level E below. A traditional cast-iron damper 8 is shown in FIG. 9 and rests with its flanges bearing on the firebox side casting 1 and 2, on the smoke shelf 7 and on the concrete lintel 4 to provide a means of fireplace closure when not in use and for the passage of flue gasses into the overlying smoke chamber level 50 when the fireplace is in use. The firebox 20 preferably includes a lining of thin fire brick 9 throughout levels A-E.

As fireplaces may vary in width the invention provides a simple means of expanding the width. Accordingly, another embodiment of level F of the fireplace of FIG. 2 and FIG. 3 is shown in FIG. 19, wherein there is shown a left firebox side casting 1, a right firebox side casting 1, a straight firebox back 2, forward right and left sidewalls 2 and lintel supports 3. Reinforcing bars 12 are placed at pertinent locations throughout the courses. This embodiment includes a spacer member 14 between the left side and the right side.

The next section is the structural shelf section 40, as shown in FIG. 1 and FIG. 11. Above the damper, supported by level F, is a rectangular reinforced concrete shelf 5 with rectangular hole 13 through the middle provided to allow the passage of flue gasses from the firebox into the smoke chamber and chimney above, and to provide structural support for the overlying smoke chamber and chimney courses. In a preferred embodiment the structural shelf is comprised of two equal parts. Continuous vertical rods 12 are used for reinforcement.

Once the flue gasses pass through the structural shelf section 40, the gasses enter the tapered smoke chamber section 50 represented by levels H and I shown in FIG. 2 and FIG. 3. The smoke chamber configuration includes identical left side and right side castings 51 as shown in FIG. 14. The castings 51 are molded and each molding, as shown in FIG. 15, may include breakaway portion 51a. The castings 51 are cast to have an extension at the end of one side so that when positioned as levels H and I a cavity is formed through which tapered chamber member 53 extends (note, FIG. 2). Depending upon the width of the firebox and consequently the chamber section 50 front and back concrete spacers 52 and 56 are provided. The tapered smoke chamber member 53 is preferably comprised of two halves 53a, 53b, each comprised of a piece of clay flue liner cut on an angle to fit together within the interior cavity, as shown in FIG. 18.

The chimney level, section 60, is illustrated by levels J1-J6, as shown in FIG. 2 and FIG. 3. As shown in FIG. 16, left side and right side pre-cast masonry chimney members 6 form the chimney structure itself. Moreover, the chimney is specifically designed so a traditional clay flue liner 63 may be inserted into the modular chimney as it is being erected. This feature differs from the many pre-fabricated flue systems that leave the construction of the chimney structure itself entirely to the user. Depending upon the width of the firebox and consequently the chimney section 60 front and back concrete spacers 62 and 67 are provided. FIG. 17 is a detailed view showing member 6, the chimney block casting including the fixed and graduated flue alignment lugs 64. The left side and right side castings 6 may be identical and cast to have an extension at the end to one side. This construction allows for multiple flue sizes in the same chimney block casting. The masonry courses, levels J1-J6, form a structural masonry chimney shaft, bearing on the flat surface of the reinforced concrete shelf 5.

The pre-cast masonry chimney members 6 are cast to include two sets of opposing integral spacer lugs 64 on the interior surface to provide proper alignment for the installation of a clay chimney shaft-liner 63 comprised of individual sections of clay chimney shaft liner which are slipped into the available space, and are vertically aligned by the concrete spacer lugs resulting in a continuous open flue passage for the fluid communication of combustion gasses from the smoke chamber to the point of exit at the top of the chimney.

Two of the opposing concrete spacer lugs 64 each include one or more cast-in score marks 65 to serve as pre-gauged break points, and these spacer lugs graduate down in their width at least once so as to introduce a stress riser at the inside corner of the integral lug casting to make them easy to break off. In this way, a portion or all of the lug may be removed so the chimney can accept one or more larger size clay flue liner member 6 based on the pre-determined measurement between lug score marks. This distinctive feature allows the same pre-cast masonry chimney unit to be used with two or more sizes of clay flue liners. This adjustment feature allows the flue cross section, and thereby its airflow capacity to be properly sized to the fireplace size and the chimney height.

Except where the clay flue liner 63 is in casual contact with the spacer lugs 64, there is an open air space between the inner wall of the masonry chimney units and the outer surface of the clay chimney shaft liner. This distinctive feature isolates the clay chimney shaft liner from the masonry chimney walls, allowing the clay chimney shaft liner to expand longitudinally without fracturing the chimney, and permits the modular fireplace system to meet building codes which call for an open air space surrounding the clay flue liner.

Another embodiment of a pre-cast masonry chimney member 6a for use with the clay flue liner 63 of levels J1-J6 is shown in FIG. 20 within a brick clad chimney. As shown in FIG. 20, the chimney structure is formed by brick 66 cladding on the outside of the chimney unified to the modular masonry core. In this embodiment the chimney is designed so that the pre-cast masonry chimney member 6a forms a modular core, and a traditional clay flue liner 63 may be inserted into the modular chimney as it is being erected. This feature differs from the many pre-fabricated flue systems that leave the construction of the chimney structure itself entirely to the user. Depending upon the width of the firebox and consequently the chimney section 60 concrete spacers 62, such as 4 inch CMU blocks, are provided. The opposing sides of flue liner member 6a have projecting concrete spacer lugs 64; each includes one or more cast-in score marks 65 to serve as pre-gauged break points. These spacer lugs 64 graduate down in their width at least once so as to introduce a stress riser at the inside corner of the integral lug casting to make them easy to break off.

The invention results in a true masonry fire box 20 as well as a true masonry clay lined chimney 60, both assembled of concrete masonry units instead of brick, which chimney will serve both as the hollow chase for the clay flue liner as well as providing the masonry mass needed to obtain buffering against moisture intrusion. By offering true masonry mass in the chimney, the invention is a real substitute for a hand-laid brick fireplace and chimney. The chimney may be flashed in the traditional manner where it passes through roof structures. Furthermore, the chimney will be capable on wet days of slowly imbibing a small amount of rain water into the interstitial masonry pores, and releasing that stored rain water as the masonry mass dries out on dry days. This buffering against the intrusion of water by virtue of its masonry mass is a characteristic of old chimneys and has been lost in the art where framed chimneys are used. Reintroducing this feature eliminates the water channeling and intrusion into the structure so common with the aforementioned modern systems that rely on flue liners mounted within the air space inside of a wood or metal framed chimney chase covered with an exterior cladding of siding, stucco or brick veneer.

The invention's most novel component is the modular chimney unit (note referenced part 6). It features integral lugs to align the clay flue liner segments as they are installed in the hollow core of the modular chimney units. Finally, the chimney provides a separation air space between the flue liner and the chimney and the attendant benefits of complete isolation of the flue liner, specifically (a) allowance for longitudinal expansion and (b) an ability to meet prevalent fire codes related to chimney construction where they require an air space between the clay flue liner and the inside of the masonry chimney wall.

The invention also offers the advantage that its components are sized and designed so they may be manufactured using existing concrete block forming technology and materials so that the invention may be widely manufactured as a commonly available product, and its installation is able to be described easily by diagram, and is simple enough to be installed as a kit by relatively unskilled installers. In addition the invention's components are sized so that they are compatible with and can easily match up with other readily available modular masonry products utilizing customary mortar joint widths.

The invention is also versatile enough to contemplate and provide for the introduction of longitudinal steel reinforcing where 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. Reinforcing details are provided as a guide. Local codes and conditions may require engineering modification of these reinforcing requirements.

While the invention has been shown and described in a preferred embodiment, modifications may be made without departing from the claimed invention. For example, fire box sizes and chimney sizes larger or smaller than those depicted may be produced utilizing concrete masonry units similarly configured, but larger or smaller than those depicted. In addition, various steel reinforcing, mortar joint and grouting details may be employed dependent on local conditions, design requirements, and building codes.