Patent Description:
Indoor grilling for restaurants and private use is known in the art. Cooking food generates smoke. Traditionally, indoor cooking with either electric or gas as a power source requires ventilation of the smoke. This often means installation of expensive, stationary, and robust ventilation systems like fume hoods and the like. The use of fume hoods is a major burden on a heating ventilation and air conditioning (HVAC) system. These overhead hoods must be physically placed directly over a cooking surface and despite their physical position, they still fail to achieve significant smoke capture. As a result, exposure to smells and inhalation of the resulting smoke is common for those in the vicinity of these systems. This also causes odor pollution. The need for proper ventilation further limits the flexibility, innovation and design of a corresponding grill or cooking surface.

In traditional Japanese steakhouses or Teppanyaki restaurants, the grills occupy a significant amount of surface area of a given floor space. The grills are fixed and stationary in order to accommodate the corresponding overhead ventilation hood system. This restricts a restaurant's ability to be creative and accommodate a variety of styles, seating arrangements, and overall design. Moreover, if the ventilation is not perfect, customers often complain of odor contamination and penetration of their clothes thereby ruining the dining experience. These indoor grills are difficult to clean and maneuver since many of the structural components are fixed to satisfy fire and safety code requirements.

Indoor recirculation grills are known. These grills and cooktops are designed in a way that does not require an overhead ventilation and hood system. However, the safety certification required to operate these grills commercially is typically governed by UL (Underwriter Laboratories) and/or ETL (Edison Testing Laboratories) standards. The UL/ETL certification requires <NUM>% capture of smoke along with fire safety response and electronic and mechanical shutdown. This can be difficult to achieve when the size of a cooking unit is reduced. For example, <CIT> shows an indoor recirculation grill with a down draft system and a filter to clean the return air. <CIT> discloses an oil mist collecting chute for collecting oil in an indoor recirculation grill. <CIT> discloses an indoor recirculation grill with a fat receiving portion of a waste receiving box. Such systems, however, are prone to accumulation of waste due to the cooking process.

Despite other attempts to solve the problems associated with existing grills, none of these teach or suggest a material and/or method having the benefits and features of the present disclosure.

The present disclosure provides for a recirculation grill including: (a) a cooktop supported by a stationary frame; (b) an intake aperture defining a plurality of slats configured for receiving smoke from the cooktop; (c) a trash compartment connected to the trough for receiving waste and grease and having a drawer for removing and cleaning; (d) an interior plenum configured to create a vacuum force to pull air and smoke from the cooktop into the intake aperture; (e) a diffuser positioned over the trash compartment and extending downwardly and outwardly; (f) a tunnel configured to receive airflow from the plenum; and (g) a blower housing enclosing a blower fan configured for pulling air and smoke from the cooktop into the intake aperture and through the plenum. The intake aperture, the plenum, and the blower can be configured to achieve <NUM>% visible smoke capture. The plenum forms an open space configured to allow airflow to expand, cool, and direct airflow from the intake aperture to the tunnel. In an example, the plenum defines segmented side walls with downward ramp sections configured to collect grease at a bottom section of the plenum. The plenum can be configured to allow at least <NUM>,<NUM> (<NUM> inches) of distance from the cook surface before contacting a first filter.

In an example, the diffuser is configured to direct airflow in two opposite outward directions. The diffuser can include a center horizontal section positioned between two opposed downwardly ramped sections extending away from the center section towards an outer plenum wall and down at an angle configured to direct airflow away and down within the plenum. In another example, the diffuser includes vertical end sections connected to the opposed ramped sections configured to direct airflow down to a lower section of the plenum. The diffuser can be formed of metal such as stainless steel. In yet another example, the plenum is configured to allow large grease particles in the air entering through the intake aperture to condense and drop out of the air and form along the plenum walls, and wherein the plenum walls are angled towards a grease trap positioned at a bottom section of the grill.

The present disclosure provides for a grill wherein the plenum walls are curved. The plenum is configured to form an upper and lower air compartment configured to form a vacuum effect at the intake aperture. The intake aperture can be configured to form enough surface area to ensure <NUM>% visible smoke capture. The trash compartment is positioned through the plenum and the diffuser forms a top portion of the trash compartment. The trough is an elongated trough extending most or all of the length of the cooktop and is positioned below the intake aperture.

The present disclosure provides for a recirculation grill that further includes a push air duct coupled to a push air blower and a push air aperture operable for trapping visible smoke from an opposite side of the cooktop over the cooktop and directing it to the intake aperture. In an example, the tunnel housing can include a wool baffle filter and a combination disposable filter having a minimum efficiency reporting value (MERV) filter and a carbon filter. The blower fan can be configured for adjusting velocity in response to a variable fan drive and control process, wherein the blower is configured to pull air and smoke from the cooktop into the intake aperture and through the plenum.

The present disclosure further provides for a recirculation grill that includes a mobile platform for supporting the blower housing and tunnel operable for slidably engaging with a stationary frame that supports the cooktop, wherein the mobile and stationary frames are modular frames formed of modular frame segments. The grill can further include a controller coupled to heating elements, the blower fan, a plurality of airflow and temperature sensors positioned within the plenum and tunnel, and a safety system. The controller is configured to monitor the blower fan and performance of any filters within the tunnel and activate the safety system if certain air velocity or temperature thresholds are surpassed.

For purposes of summarizing the disclosure, certain aspects, advantages, and novel features of the disclosure have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any one embodiment of the disclosure. Thus, the disclosure may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. The features of the disclosure which are believed to be novel are particularly pointed out and distinctly claimed in the concluding portion of the specification. These and other features, aspects, and advantages of the present disclosure will become better understood with reference to the following drawings and detailed description.

The figures which accompany the written portion of this specification illustrate embodiments and method(s) of use for the present disclosure constructed and operative according to the teachings of the present disclosure.

The various embodiments of the present disclosure will hereinafter be described in conjunction with the appended drawings, wherein like designations denote like elements.

The present disclosure provides for a recirculation grill having at least one or more of the following features: (i) a diffuser and an interior plenum operable for improved airflow into a tunnel and grease control; (ii) a waste trough extending the entire or most of a length of a cooking surface and positioned beneath an aperture; (iii) a mobile platform for maneuvering and improved access to interior components of a cooking unit for cleaning and repair; (iv) a variable fan drive (VFD) for improved efficiency and control of airflow through a filter; and (v) a combination filter operable for improvement of filter waste, cleaning, and replacement. The present disclosure provides for a recirculation grill/table that can be mobile and that satisfies specific requirements in compliance with UL/ETL safety standards. Improvements over prior grills were made that are related to ease of use/maintenance, efficient heating characteristics, and a low level of sound/vibration to not disrupt the dining experience. This included a grill/table that is modular which can be disassembled effectively for shipping and transportation.

The terms "grill" and "table" can be used interchangeably in the industry and throughout the description. Generally, a commercial kitchen or teppanyaki style restaurants will have one or more grills having a flattop cook surface heated by a plurality of electronic or gas-powered burners connected to control knobs for adjusting cooking temperature. The grill/table includes internal components positioned below the cook surface. The grill/table can include an outer housing sized and shaped to protect and conceal internal components. If the grill/table is mobile or provided in the restaurant seating area where customers are within its proximity, additional safety precautions are required.

Referring to <FIG>, an example cooking unit or recirculation grill or table <NUM> is shown. In this example, grill <NUM> includes a cooktop <NUM> positioned relatively flat above an interior portion of the grill. Cooktop <NUM> can be made from any material sufficient for cooking and ease of cleaning. In this example, the cooktop110 is fabricated as a single plate made from stainless steel. Cooktop <NUM> can define a rectangular geometry having a length "L" along a longer side and a width "W" along a shorter side. A user or cook/chef can access and manage cooking of food at a front view position along length L. For a teppanyaki style restaurant where customers are exposed and watching the cooking of their food in close proximity, patrons or customers can sit along a perimeter along the width W and opposite side from the front view. This is often desired as the experience of witnessing the cook work is a significant part of the entertainment and attraction of these restaurants.

Recirculation grill <NUM> includes interior components that support the cooktop <NUM> and make possible smoke capture resulting from cooking. As shown in <FIG>, the grill <NUM> is enclosed by sidewalls <NUM> and front face cover <NUM> and a back wall (not shown) thus forming an outer housing. These walls enclose the interior components for safety and aesthetic purposes and can also serve as a muffler to limit, reduce, eliminate unwanted noise. Positioned along cover <NUM> is a baffle filter door <NUM> that is removable to allow access to tunnel <NUM> which houses one or more filters. In an example, an optional controller <NUM> is positioned along cover <NUM> that allows a user control over heating of cooktop <NUM>, turning the grill <NUM> on and off, and providing basic diagnostic data which is viewable on a corresponding screen. In an example, the controller <NUM> includes touch screen control and compatibility along with a digital display. In a further example, controller <NUM> can be programable and include artificial intelligence and smart adaptability to adjust for specific uses to extend or improve grill efficiency and performance. This can include adjusting for hot zones associated with the cook surface and environmental conditions along with degradation of certain components.

The interior components of grill <NUM> include a tunnel <NUM> and a blower housing <NUM>. The tunnel <NUM> serves as a filter housing for holding filters operable to filter smoke and airflow that is pulled from cooktop <NUM>. As food is cooked on cooktop <NUM>, smoke and exhaust are pushed by air that is pushed through push air duct <NUM> and pulled through an intake aperture <NUM>. The smoke/air generated during use of grill <NUM> is contaminated with grease and food particles and must be filtered before released back out of grill <NUM>. Tunnel <NUM> encloses filters which often include a baffle filter and secondary filters (See <FIG>). Push air duct <NUM> is connected to a push air blower <NUM>, which directly pushes air out of the push air aperture <NUM>. Push blower <NUM> generates low speed air that is pushed across the cooktop towards intake aperture <NUM>. This forms an air curtain over the cooktop <NUM>. The air curtain in combination with a pull blower within blower housing <NUM> prevents air contamination and allows for <NUM>% visible smoke capture.

Blower housing <NUM> encloses a blower fan <NUM> that pulls air from cooktop <NUM>. The blower must be strong enough to pull air at enough velocity from the cooktop <NUM> through intake aperture <NUM>, through a plenum <NUM>, into tunnel <NUM> where the air is filtered before being pulled through blower fan <NUM> and out of grill <NUM>. This air can be referred to as "recirculated air". The recirculated air is pushed down and out through the floor to exit at the feet of the user. In an example, a louvered vent <NUM> is positioned towards the front of grill <NUM> to guide the air out and downward as it exits. In an example, blower fan <NUM> includes an inlet ring that funnels air into the blower to increase efficiency. The blower fan includes a backwards curved centrifugal fan that creates the airflow needed to capture smoke.

To heat cooktop <NUM>, a plurality of electrical heating elements <NUM> are positioned directly underneath cooktop <NUM>. In this example, three heating elements <NUM> are provided to allow for cooking or heating zones on top of cooktop <NUM>. This allows a user a variety of ways to manage cooking food by creating different temperatures across the surface. For example, one zone can be designated for warming rice and vegetables while another zone can be at a much higher heat for cooking meats and fish. The heating elements <NUM> are electrically coupled to a power source (not shown) for delivering heat to the cooktop <NUM> and control nobs (not shown) for manually controlling cooking surface temperature. In another example, digital and smart controls are employed. Gas can also be used as a heat source and is within the scope of this disclosure. Fire suppression nozzles <NUM> are positioned adjacent the intake aperture <NUM> and pointed towards the cooktop <NUM>. This is a safety measure that releases fire suppression chemicals when triggered by a failsafe safety mechanism. Safety compliance requires the presence and function of nozzles <NUM> along with corresponding sensors throughout the interior of grill <NUM>. The safety sensors are configured to trigger the nozzles <NUM> when predetermined temperature and or pressure thresholds are surpassed.

Grill <NUM> further includes a splash guard <NUM> positioned along a perimeter of the cooktop <NUM>. This splash guard <NUM> is configured to reduce and prevent grease and food from falling or being pushed off the cooktop <NUM>. This is especially helpful in a restaurant setting where customers are sitting within close proximity to the cooking surface.

In an example, grill <NUM> includes an elongated trough or a "grease" trough <NUM> which is configured to extend length L of the cooktop <NUM>. In an example, the cooktop <NUM> is <NUM>,<NUM> (<NUM> inches) along length L and trough <NUM> extends most of or the entire length L. Trough <NUM> is formed within an opening along a front face <NUM>. This allows a user to push waste and food through the opening and have it captured within the trough <NUM>. The intake aperture <NUM> is positioned directly above trough <NUM> and has openings or slats <NUM> along a backside to capture smoke and exhaust from the cooking surface. Additional grease and particles trapped in the air that is captured by the aperture <NUM> can be captured in the trough <NUM>. The waste captured in trough <NUM> is pushed to a trash compartment <NUM> which is a drawer that can be opened from the front cover <NUM> of grill <NUM>. Trash compartment <NUM> collects food scraps and grease that is pushed into the trough by the user. Trough <NUM> allows for a shorter cook surface relative to the aperture <NUM> along width W, thus allowing the air curtain to fully prevent contaminated air from escaping from the cooktop surface. Since trough <NUM> extends along length L, it is easier for a user to eliminate waste from the cooktop <NUM>. Trough <NUM> includes a downward ramp that allows waste to flow towards trash compartment <NUM>.

Additional interior components of grill <NUM> include an electrical box <NUM> which can be positioned next to blower housing <NUM> and houses electronic components and power connectors for most or all the electrical parts of grill <NUM>. This includes the blowers, heating elements, controller, and sensors. A fire tank <NUM> carries fire suppression agent which delivers the agent to the nozzles <NUM> when triggered through fire piping <NUM>. In this example, the fire tank <NUM> is positioned on an opposite side of blower housing <NUM> as compared the electrical box <NUM>. A system release module <NUM> can also be provided which is a mechanical system that releases fire suppression agent when triggered. Both sensor and mechanical safety mechanisms are required for UL/ETL compliance.

With specific attention to <FIG>, the present disclosure provides for a plenum <NUM> which defines an open space structure configured to encourage and promote efficient airflow from the intake aperture <NUM> to the tunnel <NUM>. The plenum <NUM> connects the aperture <NUM> to the tunnel <NUM>. This is the initial route air follows as it is directed towards the filtration system housed by tunnel <NUM>. The plenum utilizes a diffuser <NUM> to satisfy a safety requirement of <NUM>,<NUM> (<NUM> inches) from the cooking surface (cooktop <NUM>) before contacting a first filter by forcing air to move around the diffuser <NUM>. Diffuser <NUM> is configured to form a structure that ramps downwardly and outwardly towards plenum walls <NUM>. In this example, the diffuser includes a center section <NUM> that relatively flat or horizontal and two opposed ramped sections <NUM> that angle down and away from a plane A-A defined by the center section <NUM>. In an example, the ramped sections <NUM> extend towards plenum walls <NUM> of the outer housing of the table to cause airflow away from the center section <NUM>. The diffuser can further include vertical end sections <NUM> to allow the diffused air to flow down to the lower section of plenum <NUM>.

In an example, the diffuser <NUM> is formed of metal such as stainless steel such as <NUM> or <NUM> or the like. Various sections can be welded together. When in use, air enters through intake aperture <NUM>, hits diffuser <NUM>, which splits the air to move away in at least two different directions along sections <NUM> towards side walls <NUM>. The physical presence formed by the diffuser <NUM> forces the air out towards plenum walls <NUM> before moving down towards tunnel <NUM>. Along the way, as the space volume of the plenum increases, the air is expanding and thus rapidly cooling which forces larger particles to drop from the air prior to being filtered. This serves as a prefiltering of the smoke or whatever gas is recirculated through grill <NUM>. This diffused air must make a sharp turn around the diffuser <NUM>, which causes excess grease to sling to a bottom section of the plenum <NUM> where it will drain to a grease tray <NUM>. As grease laden air passes through the plenum <NUM>, grease naturally condenses onto the outermost walls <NUM> due to a cooler temperature of the metal. In an example, a bottom section of plenum <NUM> is angled downward along drainage sections <NUM> of walls <NUM> to allow gravity to drain the grease particles to grease tray <NUM>.

In this example, the geometry of the plenum walls <NUM> is segmented showing sharp connection points rather than a smooth curve. Although both are contemplated and within the scope of this disclosure, a segmented curve design provides ease of manufacturing since the segments can be welded together. The plenum walls <NUM> are configured to direct and encourage airflow and grease down towards the bottom section of plenum <NUM>.

The diffuser <NUM> effectively forms two air compartments, an upper plenum <NUM> above the diffuser <NUM> and a lower plenum <NUM> below the diffuser <NUM>. These air compartments create a larger ratio of the compartment opening to the cubic volume inside the compartment. A 'vacuum' effect results that is necessary for capture at the intake aperture <NUM> to generate the air velocity necessary for <NUM>% or near <NUM>% visible smoke capture. The surface area across intake aperture <NUM> creates an air ratio vs. velocity of the air and the volume of air. This is balanced within the geometry of the plenum sidewalls <NUM> to ensure <NUM>% visible smoke capture for a given size of the grill <NUM>. Changing the surface area of the intake aperture <NUM> allows for manipulating the velocity and with volume change by changing the shape of the plenum walls <NUM>, the vacuum effect can be manipulated. As volume size is decreased, velocity increases. However, an increased volume creates more demand on the blower requirement and thus the filters. Accordingly, the balance of the size and shape of the plenum <NUM> should be optimized to ensure sufficient blower requirements and smoke capture.

The trash compartment <NUM> positioning should accommodate the space requirement for plenum <NUM> as the plenum encompasses the entirety of the front portion of the table <NUM>. Accordingly, the trash compartment <NUM> does not fit directly below the cooktop <NUM> like existing indoor cook tables. In this example, the trash compartment <NUM> is placed in the center of the plenum <NUM>, extending through the plenum <NUM> to reach the underside of the cooktop <NUM>. This utilizes dead space caused by the diffuser <NUM> to minimize the effect of blocking airflow. In this example, diffuser <NUM> forms a top portion of trash compartment <NUM>.

According to the invention, the trash compartment <NUM> is positioned through the plenum <NUM> and the diffuser <NUM> forms a top portion of the trash compartment <NUM>.

The present disclosure further provides for a mobile platform operable to allow for efficient and effective maneuvering of table <NUM> and access and cleaning of the internal components. In this example, the mobile platform includes a stationary frame <NUM> which forms the structure for holding the cooktop <NUM> and some of the internal components. Stationary frame <NUM> is formed of modular frame segments <NUM> that define a mounting slot <NUM> that extends a length of the frame segment <NUM>. In this example, each modular frame segment <NUM> defines a relatively square cross section and can be cut to any desired size. In an example, the frame segments <NUM> are fabricated from aluminum or any material operable for holding table <NUM> and its components. Stationary frame <NUM> includes horizontal frame segments <NUM> and vertical frame segments <NUM>. In this example, the platform further includes wheels <NUM> which can be caster wheels or the like. The wheels extend down from horizontal frame segments <NUM> and allow for manual maneuvering of the entire table <NUM> along a floor or flat surface. This allows for desired mobility of each table <NUM> unit which improves cleaning, design, access, etc..

Stationary frame <NUM> serves as a base frame. Mobile frame <NUM> connects with stationary frame <NUM> and is operable to slide in and out within stationary frame <NUM>. In a closed configuration as shown in <FIG>, the mobile frame <NUM> is entirely positioned within stationary frame <NUM> and underneath cooktop <NUM>. In an open position, the internal components can be pulled out from the outer housing and exposed, like <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>. In these examples, the mobile frame <NUM> slides out and extends to allow access to internal components. Mobile frame <NUM> supports ductwork for the fire system, the tunnel, and the blower housing. In another example, the electrical box is further positioned on the mobile frame <NUM>. Mobile frame <NUM> can be constructed of the modular frame segments <NUM> just like stationary frame <NUM>. In this example, mobile frame <NUM> further connects to a sliding drawer <NUM> that allows for moving the mobile frame <NUM> to slide in and out of a guiding track.

Each frame segment <NUM> can be capped at each end by a connector piece <NUM>. In this example, connector <NUM> forms four protrusions <NUM> that define a channel <NUM> there between. The channel <NUM> allows the connector <NUM> to mount and connect to any other modular frame segment <NUM> by engaging channel <NUM>. Accordingly, a plurality of frame structures can be formed and designed for mounting and holding a table <NUM> and any corresponding components. This allows for improved customization and design.

In an example, the platform design consists of two parts: the mobile platform <NUM>, and the stationary frame <NUM>. The mobile platform <NUM> is attached to the stationary frame <NUM> by slides on either side of the table <NUM> along width W. When slidably separated, the stationary frame <NUM> supports the cooktop <NUM>, heating elements <NUM>, the electrical box <NUM>, thermocouples, junction box, and push air assembly <NUM>. The mobile platform <NUM> supports the blower <NUM>, tunnel assembly <NUM>, and fire system components <NUM>/<NUM>/<NUM>. In another example, the electrical box is supported with the mobile frame. With the table <NUM> open, access to a top portion of the tunnel <NUM> is easily achievable for filter access and replacement. Moreover, the right and left side of the mobile platform, where the electrical box <NUM> and fire system components <NUM>, <NUM>, and <NUM> sit respectively, and underneath the cooktop <NUM> for heating element <NUM>, maintenance is also made easier and more accessible.

Platform design allows for improved access to the internal components for cleaning, filter replacement, and maintenance. Due to the UL710B Standard for Recirculating Systems safety requirement for a minimum of <NUM>,<NUM> (<NUM> inches) and the requirement for the height of the table, filters must be at almost ground level. To reach this area to clean or replace filters would require crawling on the ground. Also due to the need for the space on either side of the tunnel for electrical and fire, there is no easy way to access the tunnel behind these systems without a mobile platform as described herein. Also, fire and electrical systems would need to be accessed from floor level without the mobile platform of the present disclosure. The present disclosure provides for a table that can separate into two sections that allow top access to the filters, electrical and fire systems.

Isolating the electrical box with the stationary frame offers an improved electrical configuration. When the box is stationary, a technician can access most areas of the table without being able to modify or touch the electrical box. This allows for a fixed connection point of the electrical box to the other components or power supply. The electrical box can include two multiplexors that are connected via coil cables. The fire system connection has its own coil cable.

Fire piping, wiring between moving parts, and securement/leveling require optimization when utilizing a mobile platform. For fire piping, the stationary frame is moved further inwards to allow the fire pipe to extend to the plenum and reach the cooktop. This allows the fire system to stay on the mobile platform. The wiring between moving parts was addressed by using curly cables that will form back to a spring like shape when not extended. Leveling is achieved by placing the frame on leveling casters that include both the leg and the wheel. For securement, the platform is attached to the frame via slides that can handle well over the platform weight. This allows the platform to handle unforeseen circumstances where extra weight is added to the platform such as a person leaning on the plenum.

<FIG> illustrates an example table <NUM> having an eating or dining surface <NUM> surrounding the cooktop <NUM>. Since table <NUM> is mobile and portable, a variety of dining surface designs can be implemented. In this example, the surface <NUM> is relatively square. However, other geometries are contemplated and within the scope of this disclosure such as round and rectangle. The dining surface <NUM> can be mobile to move with the table <NUM> or fixed to allow the table <NUM> to move in and out from the surface. It is further contemplated that a variety of materials and designs aesthetics can be implemented for surface <NUM>.

Previous models struggle with high cost of ownership since labor costs were incurred to clean an Electro-Static Precipitator (ESP) filter with proper procedures and frequency. The cost of training for employees to maintain and clean these units is relatively high. If improperly handled, the ESP can be easily damaged and caused to malfunction. The present disclosure provides for a grill that uses passive filters. In an example, passive filters include a MERV-style filter like a Merv15 and odor control combination filter (combo filter) and a wool baffle filter. These passive filters are disposable when the grease is fully saturated and it is time replace. In addition, inner compartments that require cleaning have been designed with ease of access to reduce the cleaning time. Using passive filters can increase static pressure compared to using an ESP. However, with a Variable Fan Drive (VFD) (see the flow diagram of <FIG>) that controls the blower speed, filter lifespan can be increased. In an example, the VFD can monitor up to a <NUM>% change in airflow per UL/ETL standard (unit shuts off if the airflow changes more than <NUM>%). This filter arrangement can provide for a <NUM>% visual capture rate which must be met for the smoke capture, and less than 5ppm (parts per million) of grease laden vapors measured at the exhaust for the EPA testing. This creates inverse requirements: the lowest air velocity for the proper filtration and the high air speed for capture.

Referring to <FIG>, the present disclosure provides for a combination disposable filter <NUM>. The combination filter works in conjunction with a wool covered baffle filter <NUM>. A variable speed fan is used rather than a constant speed fan to increase the lifespan of the filters. The wool baffle filter <NUM> includes a frame <NUM> that holds together a wool insert <NUM> and a baffle filter <NUM>. Baffle filter <NUM> can be removed and washed. The wool baffle filter <NUM> will first catch the large grease particulates making up most of the grease going into the system (table <NUM>). This wool covering <NUM> on the filter <NUM> is also disposable and should be replaced as needed. The remaining airborne grease will then collect on the combo filter <NUM>.

Combo filter <NUM> consists of two different filters <NUM> and <NUM> in one package. The first is a MERV filter <NUM> to collect the physical airborne grease. The second is a carbon filter <NUM>. This carbon filter <NUM> will adsorb odor producing particulates. Due to 710B requirements, a recirculating unit must shut off if the airflow changes by more than <NUM>% and detection may be needed for every filter. The variable fan drive (VFD) can increase its rpms therefore maintaining the air velocity as the filters get saturated. Due to the nature of MERV filters, as the filter gets saturated, the filtration efficiency increases, so there is no risk of losing capture as the fan speed ramps up. This allows the filters to be used for the entirety of the filter's lifespan rather than needing to be changed due to airflow requirements. To address the detection, the combo filter <NUM> was specifically designed for user ease and to limit the amount of detection required.

Previous systems utilized an Electro-Static Precipitator or ESP. Issues exist with an ESP related to cleaning and reliability. ESPs should be handled only by professionals for safety as it is a high voltage component. Also, mishandling the ESP frequently causes damage to internal plates/cells. When cells are bent or damaged the ESP will short out the power pack causing the unit to fail. With the frequency the ESP must be cleaned, it is highly likely for damage to occur when not handled by professionals.

Another challenge for filtration involves the space given for the actual filters. The filter efficiency relies on length of time grease laden air is passing through the filter. Two ways to achieve this are to slow down the air or increase the depth of the filter. To accommodate this issue, the airflow is choked and the baffle filter <NUM> is positioned at an angle (See <FIG>) within the tunnel <NUM> to increase the usable depth of the tunnel <NUM>.

<FIG> illustrates a flow diagram of a variable fan drive process <NUM>. In this example, the process <NUM> starts at box <NUM> where the airflow is measured by an airflow sensor. The airflow sensor generates an input signal at box <NUM>. The input signal at box <NUM> is then received by a programmable logic controller (PLC) at box <NUM>. This generates an output signal at box <NUM> which then moves to box <NUM> to adjust the variable fan drive (VFD). The VFD then drives the fan speed to adjust accordingly at box <NUM>.

Odor elimination and reduction is an issue to be addressed when working with recirculation grills or any indoor restaurant environment. Accordingly, in another example, a finishing filter is provided within the airflow pathway after the air has been cleaned by both the baffle filter and the combination filter. This finishing filter can include a filtering material that defines a relatively large surface area to capture and/or eliminate any remaining odor particles like fatty acids from meats. In another example, the finishing filter is specifically designed to eliminate odors resulting from the cooking of steak/beef, seafood, poultry, vegetables, rice, and cooking oils.

The present disclosure provides for a recirculation grill/table that utilizes a trough <NUM> to collect grease by draining into an interior of the grill <NUM>. Trough <NUM> is located right in front of the intake aperture <NUM>, which increases the distance required for smoke capture. Thus, the aperture <NUM> combats this disadvantage by hanging over the trough <NUM> to increase the depth of capture. In addition, the airflow can be optimized by adjusting the filter <NUM>/<NUM> makeup to handle an acceptable air speed for capture while balancing the air speed to volume ratio to create a vacuum effect. Adding push air aperture <NUM> and push air blower <NUM> on an opposing side of the cooktop <NUM> from the aperture <NUM> traps air that results in additional capture and prevents it from escaping away from the table. This causes air entrainment in the direction of the aperture <NUM> assisting in capture.

Cost reduction of service can also be achieved with grills according to the present disclosure. Previous models did not have indicators to diagnose the technical issues. For instance, an ESP generally malfunctions caused by lack of cleaning. Without proper cleaning, extensive grease/debris is built up on the ESP and creates a path for an electrical short. If correctional action is not taken, the powerpack enters a safety mode and causes the loss of filtration efficiency and smoke capture. The present disclosure incorporates indicators on fuses; highlighted short circuits as well as a smart system that alerts users via a Human Machine Interface (HMI) screen to address specific malfunctions and output instructions.

The present disclosure provides for a grill/table having standard dimensions that fit in line with other units for most kitchens. In an example, a grill/table of the present disclosure fits within standard specifications for a kitchen griddle: <NUM>,<NUM> (H) × <NUM> (L) × <NUM>,<NUM> (W) (<NUM> inches (H) × <NUM> inches (L) × <NUM> inches (W)).

The present disclosure provides for a mobile grill/table with reduced weight and size to allow the unit to be easily moved around and through doors without needing additional labor. The table weight was reduced due to elimination of a mounting plate by using cast aluminum heaters. Further, alternating from mild steel to extruded aluminum can contribute to a significant weight reduction. Extruded aluminum does not only have advantage of weight reduction, but also enables a modular design. The aluminum extrusions and subsystems are removable by bolts for field replacement while not requiring specialized knowledge. Hence, it may reduce the service costs. Additionally, shipping is simplified as frames can be partially assembled.

The present disclosure provides for user-friendly features including the ease of use/maintenance. Unlike a limited Automatic Temperature Controller ("ATC"), the grill of the present disclosure utilizes an advanced HMI (smart) system display that provides diagnostic information to end-users. These messages can alert the user to replace filters, change fuses, or be aware of an active short. It reduces the significant downtime and maintenance cost. Another advantage includes the level of maintenance for cleaning and filter replacement. As aforementioned in the cost of ownership, using passive filters with a VFD eliminates the need to clean the main active filter. As filters clog with grease, the VFD ramps up the speed of blower to a level that maintains proper air speed and capture. This continues until the filter reaches its "end of life cycle" and the HMI notifies the user to replace the filter.

Further, the mobile platform allows for the filtration, aperture, and fire system to be located on a mobile platform, which is housed within the stationary frame holding electrical system, push air, and cooktop. This allows the mobile platform to be rolled out and the filtration tunnel and other essential systems to be easily accessible for the service. For the filter replacement, simple steps of opening the tunnel door, discarding the old filter, and sliding in a new filter can be easily performed. After the safeties are properly locked and the mobile platform resumes to its original position, the unit can turn back on and operate.

Important aspects of a cooking appliance for the restaurant industry are its reliability and efficient heating characteristics including heat-up/recovery speed. Common criticism of electric appliances is that the temperature capability often cannot measure with a gas-powered unit. Reaching and retaining sufficient heating can be a major challenge as available amperage has to be split between cooking and built-in hood systems for the recirculation. In an example, for enhanced heating capacities, the present disclosure provides for a <NUM>-amp table unit so available amperage is increased. In an example, a clad cooktop is provided. Clad cooktops are combinations of aluminum, steel, and other layered metals to promote heat-transfer characteristics. Aluminum has characteristics to increase the heat transfer and reduces the heat recovery time. A casted aluminum heating assembly also covers the most area of the underside cooktop that creates a more even edge-to-edge heating characteristic.

The present disclosure provides for a table with sound and vibration reduction and canceling. For recirculating grills, a higher level of sound and vibration are produced from the motor and airflow because of the blower. A high-pitched whistling noise can result and detected by air leaks/gaps from improper manufacturing process. In an example, the exhaust exits into the grill based on the concept that the increased size of a muffler lowers the pitch. The higher pitch sounds more irritating than the lower of the same decibel level. Since a traditional muffle is not used, the grill is enclosed by a double-walled corrugated panel that muffles the sound produced within the grill. In addition, proper gasket can be used to secure the blower and all moving parts to produce the lowest possible level of the sound and vibration. The interior wall surface of the table effectively serves as a muffle which may affect the exhausted air. With high volumes of exhaust air exiting the grill underneath the frame in any direction, exhausted air is directed to a specific area in order to control turbulence and entrainment. To achieve this, a kickplate is provided around the grill to prevent the air leakage and added louvre panels and diffusers on the plenum to direct the exhaust at a downward angle.

Claim 1:
A recirculation grill (<NUM>) comprising:
(a) a cooktop (<NUM>) supported by a stationary frame;
(b) an intake aperture (<NUM>) defining a plurality of slats configured for receiving smoke from the cooktop (<NUM>);
(c) a trash compartment (<NUM>) connected to a trough (<NUM>) for receiving waste and grease and having a drawer for removing and cleaning;
(d) an interior plenum (<NUM>) configured to create a vacuum force to pull air and smoke from the cooktop (<NUM>) into the intake aperture (<NUM>);
(e) a diffuser (<NUM>) positioned over the trash compartment (<NUM>) and extending downwardly and outwardly toward opposite plenum walls;
(f) a tunnel (<NUM>) configured to receive airflow from the plenum (<NUM>); and
(g) a blower housing (<NUM>) enclosing a blower fan (<NUM>) configured for pulling air and smoke from the cooktop (<NUM>) into the intake aperture and through the plenum (<NUM>);
characterized in that the trash compartment (<NUM>) is positioned through the plenum (<NUM>) and the diffuser (<NUM>) forms a top portion of the trash compartment (<NUM>).