05/390756

10/14/1975

08/23/1973

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Cylpik, Incorporated (Winter Park, FL)

126/16

126/299D, 454/67

F24C15/20; F24C15/20

98/115K,115R 126/299R,299A,299B,299L,120,121 55/DIG.36,435 432/252 52/218,219

2841132	Range	January 1958	Philipp
2886124	Kitchen conditioner	May 1959	Scharmer
2887154	Deformable self-supporting shield	May 1959	Morningstar et al.
3190281	Fireplace flue construction	June 1965	Northwood

Myhre, Charles J.

Devinsky, Paul

Burns, Doane, Swecker & Mathis

What is claimed is

1. An exhaust duct system of the type utilized to vent grease laden vapors from a cooking facility including a canopy positioned above the cooking facility to collect grease laden vapors from the cooking facility and an exhaust duct connected to the canopy to vent the collected vapors to the atmosphere wherein the improvement comprises:

2. An exhaust duct system of the type utilized to vent grease laden vapors from a cooking facility as defined in claim 1 and further comprising

3. An exhaust duct system of the type utilized to vent grease laden vapors from a cooking facility including an exhaust duct wherein the improvement comprises:

4. An exhaust duct system of the type utilized to vent grease laden vapors from a cooking facility as defined in claim 3 and further comprising

5. A method for lining an exhaust duct of the type typically utilized to vent grease laden vapors from a cooking facility comprising the steps of:

6. A method for maintaining an exhaust system in a condition free from objectionable buildup of grease deposits as defined in claim 5 wherein said step of lining the interior surface of the exhaust duct comprises:

7. A method for maintaining an exhaust system in a condition free from objectionable buildup of grease deposits as defined in claim 6 wherein said step of combining further includes the step of:

8. A method for lining an exhaust duct of the type typically utilized to vent grease laden vapors from a cooking facility as defined in claim 5 wherein said step of providing a flexible liner comprises the step of:

9. A method for lining an exhaust duct of the type typically utilized to vent grease laden vapors from a cooking facility as defined in claim 8 wherein said step of laminating further includes:

BACKGROUND OF THE INVENTION

This invention pertains to a method and apparatus for removing grease buildup from within an exhaust system of the type utilized to vent vapors from a restaurant cooking facility.

In the restaurant industry typical cooking facilities which are utilized include ovens, grills, french fryers, etc. These devices all generate a considerable amount of grease laden vapors during a cooking operation. The vapors are collected within a hood or canopy overlying the cooking unit and are vented to the atmosphere through an exhaust duct system.

The grease laden vapors tend to cool during passage through the exhaust system and condense upon the interior surfaces of the canopy and exhaust ducts. Over a period of time and intermittent use grease deposits accumulate until the interior of the entire exhaust system is coated with a glaze of grease.

This grease buildup is highly flammable and presents a significant and continuously vexing fire hazard to the restaurant industry.

Although a real and continuing danger exists with respect to the buildup of grease within exhaust systems, restaurant owners frequently tend to be dilatory in connection with maintenance of such exhaust systems, for a number of reasons.

In this connection it is infeasible, as a practical matter, to adequately determine or measure the amount of grease buildup within an exhaust system which is typically enclosed and inaccessible for ready inspection. Therefore, it is difficult to determine if cleaning or maintenance is really necessary. A further condition which significantly detracts from enthusiasm for maintaining the exhaust system in a fire safe condition comprises excessive difficulty, in terms of time and labor, in cleaning the exhaust system. This difficulty is accentuated in multi-story buildings where an exhaust system may run vertically through several floors.

In the past two techniques have been primarily utilized to maintain an exhaust system in at least a theoretically grease free condition. These two systems included (1) steam cleaning; and (2) scraping of the exhaust surfaces with subsequent application of calcium hydroxide or calcium chloride.

Notwithstanding extensive utilization of these two systems in the past, substantial difficulties have been occasioned in attempting to utilize either of these previously known cleaning techniques.

More specifically and in connection with the previously known steam cleaning technique, the exhaust system tends to be inundated with water condensed during the cleaning operation. Further, and in this same vein, steam equipment is often difficult to control, thus providing an overspray of water onto other facilities and equipment. Moreover, complete removal of buildup resins and carbon is extremely difficult to obtain with steam cleaning equipment. Still further the work is extremely laborious. Consequently it is difficult to obtain laborers to work with such equipment.

With respect to the utilization of calcium hydroxide or calcium chloride, cleaning, scraping and coating techniques, it is extremely difficult to initially remove all of the collected grease from the exhaust ducts. Consequently in many cases only the surface layer of carbon and grease is removed. When calcium hydroxide or calcium chloride is mopped onto a surface already containing a buildup of carbon and grease, the problem is merely accentuated. In this connection these compounds tend to combine with the grease and carbon on the duct walls to build up a resin like substance which is extremely flammable once ignited. Further, these calcium compositions tend to continuously flake into the duct system potentially dropping cleaning materials onto the cooking unit or in low areas of the exhaust system. Still further, while the labor needed to utilize this technique is not as great as in steam cleaning, the quality or degree of fire protection obtained is only marginal.

Accordingly, notwithstanding the fact that grease laden exhaust systems have been at least theoretically cleaned in the past substantial room for improvement remains.

It would therefore be desirable to provide a method and apparatus which would minimize the difficulty and hazard of cleaning exhaust systems while increasing the reliability and quality of the completed work. Further it would be desirable to minimize the time and labor expense involved in an exhaust system cleaning operation. Still further it would be highly advantageous to provide a cleaning system operable in connection with multi-story high rise buildings, where accessibility within tall vertical ducts presents a significant problem.

OBJECTS OF THE INVENTION

It is therefore a general object of the invention to provide a novel method and apparatus for removing grease buildup upon the interior surface of an exhaust system in a manner which will obviate or minimize problems of the type previously described.

It is a particular object of the invention to provide a novel method and apparatus for cleaning an exhaust system wherein the reliability and quality of the cleaning operation is maximized.

It is a further object of the invention to provide a novel method and apparatus for cleaning an exhaust system wherein the time required for the cleaning operation is minimized.

It is yet a further object of the invention to provide a novel method and apparatus for cleaning an exhaust system which will minimize the laborous character of the operation of heretofore attendant exhaust duct cleaning operations.

It is another object of the invention to provide a novel method and apparatus for cleaning an exhaust system which is operable to effectively clean the interior of long vertical spans of exhaust ducts in high rise buildings and the like.

It is still another object of the invention to provide a novel method and apparatus for cleaning an exhaust system which insures complete carbon and grease removal from the exhaust system.

It is yet another object of the invention to provide a novel method and apparatus for lining an exhaust system with a readily removable and replaceable liner upon detection of a buildup of grease within the exhaust system.

BRIEF SUMMARY OF THE INVENTION

A method and apparatus for achieving at least some of the foregoing objects includes a liner removably attached to the interior surface of a canopy to provide a surface for the collection of grease and thereby isolate the canopy from the collection and buildup of grease and a liner removably attached to the interior surface of an exhaust duct to provide a surface for the collection and buildup of grease and thus isolate the exhaust duct from a substantial buildup and collection of grease. The method includes the steps of lining the canopy and exhaust ducts with removable, replaceable liners and upon the detection of a substantial buildup of grease with the exhaust system removing the liners and inserting cleaned or new liners within the exhaust system.

THE DRAWINGS

Further objects and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is an axonometric view of an exhaust system of the type utilized in a typical restaurant kitchen to vent grease laden vapors from a cooking unit;

FIG. 2 is a fragmentary perspective view of a canopy portion of an exhaust system taken from the inside thereof looking upwardly and toward the front;

FIG. 3 is a transverse sectional view through a typical canopy with liner panels according to the subject invention shown in schematic and exploded perspective;

FIG. 4 is an axonometric view of a typical canopy liner panel according to the subject invention;

FIG. 5 is a fragmentary axonometric view with parts broken away disclosing a portion of the duct system directly above an exhaust canopy including a duct liner assembly according to the subject invention;

FIG. 6 is a broken away detailed view of a section of the liner of the subject invention;

FIG. 7 discloses one technique of securing a liner according to the subject invention to a clamping bar for attachment to a duct wall;

FIG. 8 discloses an alternative means of securing a liner system according to the subject invention to a clamping bar for securing the liner to a duct wall;

FIG. 9 discloses still another means of securing a liner according to the subject invention to the side wall of a duct unit;

FIG. 10 is a typical cross sectional view through the fastener assembly as disclosed in FIG. 9;

FIG. 11 is a typical schematic cross section through a generally horizontal portion of the duct assembly upstream from the exhaust canopy;

FIG. 12 is a typical schematic cross section through a first generally vertical duct segment extending between a canopy and a horizontal duct segment as depicted in FIG. 5;

FIG. 13 is a detailed view of an assembly for raising and lowering a liner panel within the interior of an exhaust conduit according to the subject invention;

FIG. 14 is a side elevational view of the raising and lowering assembly depicted in FIG. 13;

FIG. 15 is a typical cross sectional detailed view taken along section 15--15 in FIG. 13;

FIG. 16 is a plan view of the raising and lowering mechanism according to FIGS. 13 and 14;

FIG. 17 is a typical cross sectional view through a vertical duct with a removable liner attached thereto according to the subject invention;

FIG. 18 is a typical cross sectional detailed corner view as circled in FIG. 17; and

FIG. 19 is a detailed view of an assembly for maintaining tension upon a duct liner according to the subject invention at a base portion of the duct.

DETAILED DESCRIPTION

Context of the Invention

Before discussing in detail an illustrative embodiment of the subject invention it may be helpful to identify the context of the invention in terms of an environment of primary utilization. In this connection, and with reference to FIG. 1, there will be seen an exhaust system 20 of the type utilized in a restaurant kitchen 22, including a canopy 24 positioned generally vertical above a cooking facility 26. The cooking facility 26 may include a grill portion 28, an oven 30 and a french fryer unit 32, etc. Each of these cooking devices tend to generate grease vapors during cooking operation which vapors rise by convection and are collected within the overlying canopy 24.

The exhaust system 20 further includes a main vertical duct 34 which extends through multiple floors 36 of the restaurant building and exits at the upper end 38 thereof into the atmosphere. The main vertical duct 34 may extend directly into the canopy 24 or may be connected thereto by an L-shaped duct 40.

As previously discussed, the grease vapor is collected within the canopy 24 and vented to the atmosphere through the ducts 34 and 40. As the hot vapors pass into the canopy and through the duct system, they tend to cool and deposit grease upon the interior surface of the canopy and the exhaust duct system. This grease over a period of time tends to build up within the exhaust system and presents a significant fire hazard.

The subject invention is directed to a method and apparatus for maintaining an exhaust system, typically of the foregoing type, in a relatively clean, grease-free condition by the provision of a removable liner assembly which obviates or minimizes problems of the type previously described.

Exhaust System Canopy

Referring specifically now to FIGS. 2-4, there will be seen a typical canopy assembly 24 of the type previously discussed operable to collect vapors and to funnel the collected vapors into an exhaust duct 40. In order to minimize the amount of grease that passes into the duct system, a conventional tortuous path filter 42 is frequently positioned across a back wall 44 of the canopy.

The canopy 24 includes a generally horizontal top wall 46 and a sloping front wall 48. The canopy is enclosed with sloping end walls 50 and 52.

According to the subject invention each of these walls are covered by a removable liner system 52 such as illustrated in FIG. 2. This liner system includes a plurality of individual panels 54 which are attached to the inner surface of the canopy along the side wall by metallic strips 58 and sheet metal screws 60. The corners are fastened by angle iron strips 62 and sheet metal screws 63. At the bottom edge of the canopy, which is normally fashioned with a grease trough 64, note FIG. 3, the panels 54 are appropriately contoured and connected to an upwardly projecting lip 66 by the provision of metallic clips 68.

Each of the panels 54, as illustrated in FIG. 5 is a relatively small member as compared with the overall extent of the canopy and thus is easily removable and can be handled by a single laborer. Accordingly, once the panels 54 are removed, each panel may be individually transported and cleaned within a vat in a convenient and accessible posture.

When it is anticipated that removal and cleaning will be desired, the panels 54 are typically composed of a galvanized sheet material or a stainless steel which will resist corrosion. Alternative the individual panels 54, note FIG. 4, may be fashioned from thin aluminum sheet material which upon removal may be discarded and a new sheeting may be readily fashioned and applied.

It should be appreciated that removal and cleaning or removal and discarding is a substantial advance in terms of cleaning of a canopy when considered with respect to the difficulty a worker might encounter with respect to scraping grease or utilizing steam spraying equipment projected upwardly within the interior of the canopy.

Duct Liner System

Referring now particularly to FIGS. 5 and 6 there will be seen a liner assembly or lamina 80 of the type utilized to line an exhaust duct according to the subject invention. More particularly the exhaust system liner is fabricated with a metallic backing member 82 which may be, for example, a wire mesh or screen composed of galvanized copper, aluminum or steel. The wire backing member 82 provides form and strength to the liner assembly. The liner is further composed of an innermost sheet 84 of asbestos material. Asbestos is preferred because of its resistance to burning and porosity or ability to collect and hold grease that tends to deposit upon the duct wall.

In one preferred embodiment a vapor barrier 86 is interclad between the asbestos inner liner 84 and the metallic backup member 82. This liner is preferably fabricated from a fireproof paper, such as NOMEX paper. NOMEX is a trademmark of the E. I. duPont de Nemours & Co. and comprises a heat-resistant nylon, the copolymer of meta-phenylenediamine and isophthaloyl chloride. It retains useful properties after long-term exposure to temperatures up to 220°C. and does not support combustion.

The lining composition 80 is applied throughout the interior of the exhaust system.

The liner is applied within small vertical section 88 of duct 40 and is held at the corners by the provision of angle iron strips 90. These strips 90 are removably attached at the corners of the duct walls by sheet metal screws, not shown. The bottommost portion 92 of the liner is connected to the wall by fastening means such as detailed in FIGS. 7 and 8.

More specifically in FIG. 7 there is disclosed a metal cleat or clip 94 which is resilient and is designed to interferingly fit about a lower portion of the liner 80 which is wrapped around a horizontal edge bar 96 of the vertical duct wall 88.

An alternative attachment assembly is disclosed in FIG. 8 and in this connection a horizontal metallic strip 98 is depicted as being riveted to the liner composition 80 by rivets 100. The metallic strip 98 may then be secured to the duct wall 88 by the provision of a sheet metal screw 102, note particularly FIGS. 5 and 8.

Access to the vertical duct segment 88 is provided by a removable panel 92 to facilitate inspection and application, removal and replacement of the short liner segment.

In some instances it is desired to pin mid span portions of the liner against the duct walls. This may be accomplished by the provision of pin lock assemblies 104, such as detailed in FIGS. 9 and 10. More specifically a metallic base 106 is spot welded to a portion of a duct wall 108. The base is provided in a central portion thereof with a normally extending post 110. The post is fashioned with a sharp point 112 which is operable to penetrate the liner composition 80. The liner 80 may be pinned upon the post by the application of a circular mounting pad 114, having a small central aperture 116 designed to interferingly fit with the post 110, note particularly FIG. 10.

Referring now specifically to FIGS. 11 and 12, there is disclosed typical schematic cross sectional views taken through the horizontal duct portion 120 and the vertical duct portion 88 of the L-shaped connecting section 40. In this connection in the horizontal duct portion 120 the liner 80 may be a continuous wrapping which is overlapped at its edge as at 122 and is removably connected to the duct 120 by the provision of corner strips 124 which may be attached to the interior surface of the duct 120 by the provision of sheet metal screws, not shown.

Referring now to FIG. 12 there is disclosed a typical schematic cross section of the vertical duct portion 88 and illustrating an alternative manner of lining the duct wherein four panels 126, 128, 130 and 132 are utilized. The edges of panels 128 and 132 underly the edges of panels 126 and 130 and thus when these members are affixed to the duct corners by angle strips 90, note FIG. 5, an overlapping seal at the edges will be provided.

With particular reference now to FIGS. 13-19 there will be seen a system for lining a vertical duct portion of the exhaust system which may be advantageously utilized to line even long spans such as exist in multi-story buildings. More particularly the liner 80 is wrapped around wire cables 134 and 136 at the edges thereof, note particularly FIG. 15, and securely attached thereto by conventional fasteners 138. The panels 80 typically are preformed and wound upon large rolls for positioning at the base of the vertically extending duct portion 34. Housing cables 140 and 142, corresponding to cables 134 and 136 may then be lowered from the uppermost portion 144 of the duct 134 and attached to the liner cable by cleats 146 and 148, respectively.

The hoisting cables 140 and 142 pass over sheathes 150 and 152 and are wound upon a dual winch system including spools 154 and 156, respectively. These spools are simultaneously wound by a common axle 158 which may be controlled by a hand lever 160. The take up spools 154 and 156 are mounted upon suitable brackets 162 and 164 which in turn are removably connected to support plates 166 and 168 by conventional threaded fasteners 170 and 172.

The take up winch assembly is rendered horizontally adjustable by thr provision of brackets 162 and 164 which are adjustably connected upon a horzontally extending bar 174. Thus, as illustrated more clearly in FIG. 16, the hand operated take up winch assembly 150 may be moved around the sides of the duct 34 and sequently positioned for support upon permanently mounted support plates 166, 168, 176 and 178.

Once one panel or liner 80 is raised to cover one side wall of the vertical duct 34, the panel may be attached at the uppermost portion thereof onto the upper edge 144 of the duct 34 by mechanical fastening means extending through the duct and a horizontally extending support bar 180 positioned across the liner.

In a preferred embodiment, note FIG. 17, a first panel 182 is raised and secured within the duct 34. A second oppositely positioned panel 184 is then raised and positioned within the duct. Sequentially then end panels 186 and 188 are raised and secured within the duct.

With reference now particularly to FIG. 18, which is a blown up sectional view of a corner of the subject duct assembly, it will be seen that panel 186 at an edge portion 190 is designed to overlay panel 184. The cables within the edges of the panels 184 and 186 are stretched tautly to draw the liner into the corners of the duct 34 to hold the liners against the interior surface of the vertical duct.

Maintenance of the liner against the duct walls may be further facilitated by the application of a plurality of clamping assemblies such as illustrated and previously described in connection with FIGS. 9 and 10.

Additionally spring loaded telescoping cross braces 187 and 189 (note FIG. 17) may be inserted at a plurality of elevations within the duct 34 at access locations 191 (note FIG. 1).

Still further, the liners 80 may be additionally induced to lie against the duct wall 34 by the application of continuous downward tension upon the liner by a biasing device 200, note particularly FIG. 19. More specifically the liner 80 is provided at its lower end by a horizontally extending metal bar 202 which is provided with a spring bias assembly 204 to bias the lowermost portion of the liner 80 against the duct wall 34.

A downward bias is applied to the biasing assembly 204 by the provision of a second biasing assembly 206 which is normally connected to assembly 204. In order to permit movement of assembly 204 in a vertical direction, a slot 208 is fashioned within the duct wall 34. Thus spring 210 of assembly 206 serves to bias the liner 80 in a downward direction and facilitate the maintenance of the liner against the duct wall 34.

Once the liner has been installed within the L-section 40 and the vertical section 34 of the exhaust duct system, the cooking facility 26 is utilized in a conventional manner. The liner is periodically inspected to determine the quantity of grease buildup upon the liner wall. Once it has been determined that a sufficient grease buildup has occurred so as to require removal, the liner is merely removed by reversing the foregoing process. At this point in time the asbestos layer may be stripped from its metal backing sheath and a new clean layer applied. The reassembled liner free of grease accumulation is then pulled back into the exhaust system.

Alternatively the entire liner may be discarded and an entirely new liner including metal backing member may be inserted.

SUMMARY OF THE MAJOR ADVANTAGES OF THE INVENTION

In discussing a preferred embodiment of the invention, several distinct advantages of the invention have been specifically and inherently delineated.

More particularly a principle advantage of the subject novel method and apparatus comprises the provision of the removable liner positioned within a canopy of an exhaust system in combination with a removable liner positioned within the duct system. These liners may be removed and replaced or removed and cleaned and thus eliminate difficulties previously associated with in situ steam and chemical cleaning operations.

By the provision of the subject invention, the completeness and quality of the cleaning operation is substantially enhanced while significantly reducing the difficulty and the amount of time required to clean a duct system. Further local authorities charged with minimizing potential fire hazard in a community are provided with a positive means by regulating the frequency of which the liners must be replaced.

A further significant advantage pertains to the ease of application and broadening the base of work force willing to encounter the task of cleaning exhaust systems.

Still further the subject invention provides a ready means for lining and replacing linings in exhaust ducts even when great heights are encountered.

Other significant advantages pertains to the novel method and apparatus for mounting the liners within and against the exhaust duct walls.

While the invention has been described with reference to preferred embodiments, it will be appreciated by those skilled in the art that additions, deletions, modifications and substitutions or other changes not specifically described may be made which will fall within the purview of the appended claims.