Patent Application
20070169948
1. Field of the Invention
This invention relates to a system and method of containing a fire within a semi-enclosed space.
2. Discussion of the Prior Art
Fire suppression is an important consideration in mechanical equipment housings. This is especially true with respect to a cooking apparatus, such as an oven, fryer, or griddle. For example, in the field of popcorn machines, fire is a risk because popcorn requires heating corn and oil to produce popcorn. Typically popcorn is prepared in a kettle contained in a cabinet. The kettle contains an electrical heating element which heats the corn and oil to produce popcorn.
In the case of a fire, prior art systems are available to provide power cutoff, but for maximum protection, it is desirable for the fire to be contained within the semi-enclosed space as long as possible to protect a user as well as to provide time to put out the fire. In order to comply with newer safety regulations, the advent of fire must be contained within a certain period of time while fire suppression systems, such as are commercially available from Ansul Incorporated, are activated. The containment of fire within a certain area within a machine is particularly challenging because in a semi-enclosed space, after a fire consumes the available oxygen available within that space, the fire will escape outside the semi-enclosed space in order to seek fresh combustion air to continue the fire. Prior art systems tend to try to reduce the amount of air available, under the theory that a fire cannot continue without more air for combustion. However, given the semi-enclosed nature of such equipment, such prior art systems suffer from the fact that the fire seeks to expand out of the semi-enclosed space to continue the combustion. Unfortunately, this is the same area in which an operator is most likely to be located when trying to control the fire or access controls on the machine to shut off the cooking element. Thus, this tendency of the fire to surge outward is particularly dangerous to any nearby operators, as well as to the nearby surroundings.
Considering these disadvantageous features of prior art systems, there is a need for a fire containment system that intentionally directs fire away from an open side of a semi-enclosed space. There further is a need for a fire containment system that supplies a source of combustion air within the semi-enclosed space to direct the fire toward a rear wall, providing enhanced safety to nearby operators and surroundings, as well as increased time to control and extinguish the fire.
The present invention addresses shortcomings in prior art fire containment systems, while providing the above mentioned desirable features.
The purpose and advantages of the present invention will be set forth in and apparent from the description and drawings that follow, as well as will be learned by practice of the invention.
The present invention is generally embodied in a fire containment system. In a first aspect of the invention, a fire containment system is provided for containing the outbreak of a fire in a semi-enclosed space, where the semi-enclosed space is defined by at least two side panels, a back panel, a top panel and a bottom panel. The system has a first vent in communication with the semi-enclosed space and a first blower adapted to exhaust air from the semi-enclosed space through the first vent. The system also has a second vent located in the top panel in communication with the semi-enclosed space and being disposed opposite an open side of the semi-enclosed space, and a second blower adapted to direct air into the semi-enclosed space through the second vent. The system is adapted such that if a fire starts in the semi-enclosed space, the first blower exhausts combustion air from the semi-enclosed space through the first vent while the second blower provides a source of combustion air to the semi-enclosed space through the second vent, thereby encouraging the fire to stay within the semi-enclosed space.
In a second aspect of the invention, a cooking apparatus is provided having a fire containment system, the cooking apparatus comprising a semi-enclosed cooking space defined by at least two side panels, a back panel, a bottom panel, a top panel and a front that may be opened between the two side panels, a cooking surface having at least one heating element and being located within the semi-enclosed cooking space, a first vent in the top panel above and in communication with the semi-enclosed cooking space, a first blower adapted to exhaust air from the semi-enclosed cooking space through the first vent, a second vent located in the top panel above and in communication with the semi-enclosed cooking space, a second blower adapted to direct air into the semi-enclosed cooking space through the second vent and proximate the back panel, a temperature sensitive coupling adapted to detect the presence of fire and to turn off the at least one heating element, and wherein if a fire ignites in the semi-enclosed cooking space, the first blower continues to operate to exhaust the combustion gases while the second blower provides air for combustion within the semi-enclosed cooking space, encouraging the fire to stay within the semi-enclosed cooking space.
In another aspect of the invention, a method of containing an outbreak of fire within a semi-enclosed space is disclosed where the semi-enclosed space is defined by at least two side panels, a back panel, a bottom panel, and a top panel and having an open front between the two side panels. The method includes providing an exhaust vent in communication with the semi-enclosed space, providing a first blower in communication with the exhaust vent, exhausting air from the semi-enclosed space through the exhaust vent via the first blower, providing an inlet air vent in communication with the semi-enclosed space, providing a second blower in communication with the inlet air vent, providing air to the semi-enclosed space through the inlet air vent via the second blower, providing a temperature sensitive coupling adapted to decouple at a pre-selected temperature, providing electrical circuitry to control the interaction between a heating element, the temperature sensitive coupling, and the first and second blowers, and wherein if a fire starts in the semi-enclosed space, the temperature sensitive coupling decouples the heating element, while power continues to be supplied to the first and second blowers and the first blower exhausts combustion gases while the second blower provides inlet air to the semi-enclosed space wherein the fire is kept from spreading beyond the semi-enclosed space.
In yet another aspect of the invention, at least one nozzle is directed toward the semi-enclosed space, and the nozzle is adapted to spray fire extinguishing material.
Thus, the present invention provides an alternative to prior art fire containment methods and systems. The present invention uses a counter-intuitive system which seeks to feed combustion air to a fire within a particular location of a semi-enclosed space, so as to encourage the fire to remain within the semi-enclosed space. This system reduces the air handling capacity required to exhaust the combustion gases present in the event of a fire, because the fire is less likely to expand outward from beneath a hood unit located over the semi-enclosed space. Indeed, because the fire containment system results in a smaller, more localized fire, a hood unit having a somewhat reduced air flow capacity may be used. The new method and system improve the ability to handle the outbreak of a fire, while providing critically important increased time for the fire to be extinguished by a fire suppression system which is automated or manually activated by an operator.
It is to be understood that both the foregoing general description and the following detailed description are not limiting but are intended to provide further explanation of the invention claimed. The accompanying drawings, which are incorporated in and constitute part of this specification, are included to illustrate and provide a further understanding of the method and system of the invention. Together with the description, the drawings serve to explain the principles of the invention.
These and further aspects and advantages of the invention will be discussed more in detail hereinafter with reference to the disclosure of preferred embodiments, and in particular with reference to the appended Figures. In describing the preferred embodiments, reference is made to the accompanying drawing Figures wherein like parts have like reference numerals, and wherein:
It should be understood that the drawings are not to scale and provide examples involving a fire containment system within the scope and spirit of the present invention. While considerable mechanical details of such a system, including other plan and section views of the particular components, have been omitted, such details are considered well within the comprehension of those skilled in the art in light of the present disclosure. It also should be understood that the present invention is not limited to the preferred embodiments illustrated.
While the present invention is capable of embodiment in various forms, there is shown in the drawings and will hereinafter be described a two presently preferred embodiments with the understanding that the present disclosure is to be considered as an exemplification of the invention, and is not intended to limit the invention to the specific embodiments illustrated.
Popcorn case 12 preferably has a semi-enclosed space defined by a series of panels or walls. The term wall or panel used in this context is intended to mean a boundary which may or may not be a planar surface. Thus, “panel” is intended to include structures such as physical building walls, but also could include a variety of other shapes and features, such as the inside of a concave hood, or other obstructions and structures, such as a top of a stove unit having burners or other heating elements. Thus, in a broad sense, popcorn case 12 is representative of a semi-enclosed space having a bottom panel 16, a top panel 18, a back panel 20, and a pair of side panels 22 and 24, which collectively define the semi-enclosed space. Back panel 20 and side panels 22 and 24 are typically made of stainless steel or other opaque materials. Alternatively, these panels may be constructed of tempered glass, plexiglass or other transparent or semi-transparent materials to allow a view of the popping process, as well as the completed popcorn which is stored in popcorn case 12. In this example, access to popcorn case 12 is provided by means of a pair of hinged doors 26 and 28, which may also be made of plexiglass or other suitable materials, to permit the operator to carry out cooking operations and to dispense popcorn when desired. It will be appreciated that doors 26 and 28 are able to be opened to gain access to the semi-enclosed space, as needed, and that in some variations, the front may simply remain open, such as in the case of a griddle, or may use a single door. A tiltable drop-down shelf 29 spans the front opening to retain popped popcorn when doors 26 and 28 are opened.
A control unit 30 also is mounted under the bottom panel 16, between popcorn case 12 and the storage section 14, and behind a control panel 32. Control panel 32 has buttons or switches by which control unit 30 can be activated. Circuitry involving control unit 30 is shown in
In machine 10, popcorn kernels are placed into a kettle 38 which is suspended from top panel 18 of case 12. It will be appreciated that kettle 38 alternatively may be suspended on a pedestal or from an arm that would be attached to a cabinet back or side panel. Kettle 38 is constructed of stainless steel or nickel plated steel. Kettle 38 has one or more electric heating elements 40 located in its walls, but it will be appreciated that heating elements for the purpose of cooking may be electric or may be supplied with combustible fuel sources, such as a propane gas burner. In the present embodiment, heating elements 40, when activated, are utilized to heat oil contained within kettle 38 and to pop the kernels of corn placed into kettle 38 by an operator. A thermostat 42 is located on kettle 38 to sense the temperature of kettle 38.
Kettle 38 is supported on a pivot axis (not shown) carried within a support column 46 extending from top wall 18 of popcorn case 12. A kettle dump handle 48 is connected to the pivot axis of kettle 38, so that by rotating dump handle 48, kettle 38 may be tipped on the pivot to allow popped popcorn to be discharged from kettle 38 into popcorn case 12.
Kettle 38 has a cover 44 which is circular in shape and is suspended by means of a support rod 50 which extends through the center of cover 44. Support rod 50 encloses a drive shaft (not shown) as part of an agitator 56 which includes a motor that drives a number of mixing blades in the kettle (not shown). The agitator 56 is used to agitate the kernels in kettle 38, to ensure more even cooking. Kettle cover 44 may be opened via a cover lift rod 58 to add kernels. Popcorn machine 10 has lights 60 which are used to illuminate case 12. Machine 10 also has a warmer unit 62 which uses a heating element to maintain the warmth of popped popcorn in case 12.
As best seen in
Hood housing 80 includes a metallic hood 82 which extends over popcorn case 12 to contain heat from case 12 and to prevent any potential flame from coming into direct contact with a ceiling or anything above the hood. Hood housing 80 contains an exhaust blower 84 which serves to vent exhaust gases from semi-enclosed popcorn case 12. Thus, any undesirable odors may be reduced and airborne oils eliminated from the area around machine 10. Exhaust blower 84 preferably is of a squirrel cage configuration, such as is available from Fasco, but may be of other suitable configurations.
Vent support housing 78 is located between top panel 18 and hood housing 80. Vent support housing 78 has a pair of side panels 92 and 94, a front panel 96 and a rear panel 98. Vent support housing 78 has an intake vent 86 which provides exhaust air access between case 12 and hood housing 80. Vent 86 preferably directs heat and exhaust gases from the semi-enclosed space of case 12, through a three filter system 88 including charcoal, electro-static and grease filters, and around a partition 89 to reach exhaust blower 84, as best seen in
A fresh air blower 102 is mounted near rear panel 98 of vent support housing 78. Fresh air blower 102 provides additional fresh air into case 12 and is controlled by control unit 30 to continuously operate. The air flow generated by blower 102 is circulated through a secondary vent 104 which is located in top panel 18 of case 12. A removable side access 106 serves as an inlet source of fresh air to blower 102, and allows maintenance access to blower 102, as well as the other components housed in vent support housing 78. As with exhaust blower 84, fresh air blower 102 preferably is of a squirrel cage configuration, such as is available from Fasco, although alternative configurations may be used. It will be appreciated that depending on the desired installation configuration, the vents associated with blowers 84 or 102 essentially may be formed by the housing of the respective blower unit, such as with vent 104.
Machine 10 has a fire containment system which is activated if the temperatures in case 12 exceeds a certain pre-selected threshold temperature as will be explained further herein. A temperature sensitive coupling 108 is installed above kettle 38 in the form of a fusible link, as seen in
A pair of nozzles 110 and 112 are installed in the top of case 12, and another nozzle 114 is installed in vent 86. Nozzles 110, 112 and 114 are provided to spray a fire extinguishing material or composition, as is provided preferably by a fire suppression system such as by Ansul Incorporated. In this system, nozzles 110, 112 and 114 are supplied with a fire extinguishing agent, such as CO2 or foam, via a storage tank 143 which preferably is stored in cabinet 14, with tubular connections routed up through corner support members 70, 72, 74 or 76, and within vent support housing 78, as needed.
A power cord 150 is connected to control unit 30 to provide machine 10 with the necessary electrical power to operate the various components. Power cord 150 is a conventional four line power cord which may be plugged into a normal 208/240 volt power source. All of the machine elements described above are operatively interconnected and functionally controlled by control unit 30, as shown in
Power cord 150 provides power for the electrical components of machine 10. Power cord 150 is electrically connected to components within hood housing 80. In essence, power is supplied via power cord 150 to a switch 172 which controls the power to blowers 102 and 84 via a hood contact junction 152. Hood contact junction 152 is located in hood housing 80 and is coupled to the electrical components in control unit 30, such that power comes in to contact junction 152 and then flows to control unit 30. Thermostat 42 is coupled to a pilot light 154 and a relay 156. Relay 156 is controlled by a kettle switch 158 which allows the user to connect power to heating elements 40 of kettle 38 to cook and thereby pop the popcorn. Thermostat 42 is programmed to interrupt power to heating elements 40 after a pre-selected temperature is reached which is designed to pop the popcorn. It will be appreciated that alternative heating and thermostatic circuitry could be employed, such as is disclosed in U.S. Pat. No. 6,872,923.
Hood contact junction 152 is coupled to a relay 160, which in turn is coupled to emergency fire suppression override switch 146. If switch 146 is pulled, further switch 144 for the suppression system is triggered interrupting relay 160, and thereby interrupting power from hood contact junction 152 to particular electrical components controlled by control unit 30. Relay 160 also is mechanically coupled via fusible link 108, such that if fusible link 108 melts due to the excessive heat caused by a fire, relay 160 will be decoupled or tripped, interrupting power from hood contact junction 152 to control unit 30.
Control unit 30 allows activation and deactivation of various features of machine 10. A pump switch 162 is coupled to control unit 30 and activates an oil pump 164 to pump oil into kettle 38, while heating elements 40 heat kettle 38 to pop the corn. An agitator switch 166 controls operation of agitator 56. A conditioner switch 168 controls warmer unit 62 and a lights switch 170 controls lights 60. These types of components are disabled if power from contact junction 152 to control unit 30 is interrupted.
Importantly, in the event of a fire or when emergency switch 146 is pulled, while the power is decoupled or shut off from heating elements 40 and other electronic components controlled by control unit 30, power continues to flow to blowers 102 and 84 through contact junction 152 in hood housing 80. Thus, power is not interrupted to blowers 102 and 84, even when relay 160 is tripped. A further safety fuse 174 also is provided in series with the power lines to the electrical components to avoid potential electrical overloads.
Fusible link 108 is provided to trigger relay 160 which controls the switches 158, 162, 166, 168 and 170 and heating elements 40. Fusible link 108 is selected to melt or break, thereby triggering relay 160, at an appropriate temperature which indicates combustion or fire in cabinet 12. Hence, with the fire containment system of the present invention, if fusible link 108 melts, power is immediately interrupted to all components except exhaust blower 84 and inlet air blower 102. Blower 102 provides inlet air via vent 104 to contain a fire within case 12, while the exhaust blower 84 removes the combustion products, such as heat and smoke, via vent 86. It also will be appreciated that if the heating elements are alternatively associated with a combustible fuel, such as a propane gas burner on a cooktop, the circuitry may be designed to activate closure of a gas valve, shutting off the flow of gas to the heating element, in the event that a fire is sensed in the semi-enclosed space.
Contrary to the conventional thinking that it is unwise to provide air to an unwanted fire, the fire containment system of the present invention contains a fire by providing a specifically located source of air for combustion via blower 102 and vent 104. The fire thus is drawn toward vent 104 which is located near the rear of case 12, rather than escaping the bounds of the semi-enclosed space of case 12. These actions, which encourage the fire to stay within the semi-enclosed space, create highly advantageous additional fire containment time, and allow foam or another flame extinguishing material to be applied via nozzles 110, 112 and 114, to extinguish the fire. Depending on the particular requirements of the user, inlet air blower 102 may be configured to automatically shut off once fire extinguishing material has been applied to the semi-enclosed space, or on a time-delayed circuit. Similarly, exhaust blower 84 may be configured to automatically shut off on a time-delayed circuit.
Turning to
It will be apparent to those skilled in the art that the fire containment method and system in accordance with the present invention may be provided in various configurations without departing from the spirit or scope of the invention. Any variety of suitable materials of construction, configurations, shapes and sizes for the components and methods of connecting the components may be utilized to meet the particular needs and requirements of an end user in constructing a fire containment system consistent with the present invention. Thus, the present invention is not limited by the foregoing descriptions but is intended to cover all modifications and variations that come within the scope and spirit of the invention and the claims that follow.
