Mobile recirculating grill with variable fan drive

Abstract

A recirculating grill includes a cooktop and an air inlet having a plurality of slats, the air inlet being configured to draw smoke from the cooktop; an internal plenum configured to generate a vacuum force to pull air and smoke from the cooktop into the air inlet; a diffuser located within the plenum and extending downwardly and outwardly; a duct configured to receive airflow from the plenum and having at least one filter; a fan housing enclosing a variable speed fan, the variable speed fan being configured to pull air and smoke from the cooktop into the air inlet and pass the plenum into the duct; and a variable fan drive (VFD) for controlling the variable speed fan to increase filter life. The air inlet, plenum, and fan are configured to achieve a 100% visible smoke capture rate.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 62 / 884,014, filed on August 7, 2019, which is hereby incorporated by reference in its entirety into this application. Technical Field

[0003] The present application relates generally to the field of indoor grills and cooking stations, and in particular to recirculating grills / stations. Background Art

[0004] Indoor grills for restaurant and private use are well known in the art. Cooking food creates smoke. Traditionally, indoor cooking using electricity or gas as an energy source requires smoke extraction. This usually means installing expensive, static and rigid ventilation systems such as smoke hoods. The use of smoke hoods is a major burden on the heating, ventilation and air conditioning (HVAC) system. These overhead smoke hoods must be physically placed directly above the cooking surface, and even if they are so physically located, they still do not achieve significant smoke capture effects. Therefore, it is common to be exposed to odors and inhale the resulting smoke when breathing when in the vicinity of these systems. This also causes odor pollution. The need for proper ventilation further limits the flexibility, innovation and design of the corresponding grill or cooking surface.

[0005] In a traditional Japanese steakhouse or teppanyaki restaurant, the grill takes up a significant amount of floor space within a given indoor footprint. The grill is fixed or stationary to accommodate the corresponding overhead ventilation hood system. This limits the restaurant's ability to create and accommodate a variety of styles, seating arrangements, and overall design. In addition, if ventilation is not perfect, customers often complain about odor contamination and seeping into their clothing, ruining the dining experience. These indoor cooktops are difficult to clean and operate because many of its structural components are fixed to meet fire and safety regulations.

[0006] Indoor circulation grills are well known. These grills and cooktops are designed to eliminate the need for overhead ventilation and fume hood systems. However, the safety certifications required to commercially operate these grills are typically governed by UL and / or ETL standards. UL / ETL certification requires a 100% smoke capture rate as well as fire safety response and emergency shutoffs both electronic and mechanical. This can be difficult to achieve as the size of cooking equipment decreases.

[0007] While other attempts have been made to address the problems associated with prior art grills, none of these attempts teach or suggest materials and / or methods having the advantages and features of the present invention. Summary of the invention

[0008] The present disclosure provides a recirculating grill comprising: (a) a cooktop supported by a fixed frame located above an adjustable heating unit; (b) an air inlet having a plurality of slats and configured to draw smoke from the cooktop; (c) an internal plenum configured to generate a vacuum force to pull air and smoke from the cooktop into the air inlet; (d) a diffuser located above a waste bin and extending downwardly and outwardly; (e) a duct containing at least one filter configured to capture unwanted particles from the circulating air and smoke from the plenum; (f) a fan housing enclosing a variable speed fan configured to adjust speed in response to a variable fan drive (VFD) and a control process, the fan configured to pull air and smoke from the cooktop into the air inlet and pass the air and smoke through the plenum into the duct; and (g) a controller connected to the VFD, the controller configured to adjust the fan speed of the fan to adjust the use of the filter.

[0009] In one embodiment, the at least one filter comprises a wool baffle filter. In another embodiment, the grill further comprises a combination disposable filter having a minimum efficiency reporting value (MERV) filter and a carbon filter located downstream of the wool baffle filter, wherein the combination disposable filter is provided as a single unit. The combination of filters is configured to provide a 100% visible smoke capture rate from the cooktop and a vapor grease content of less than 5 parts per million measured at the exhaust port. The baffle filter is positioned at an angle within the duct and is configured to form a barrier to the airflow before the airflow contacts the combination disposable filter. In another embodiment, an odor control elimination end filter is provided in the duct.

[0010] In another embodiment, a controller is connected to the heating unit, the variable speed fan, a plurality of airflow and temperature sensors located within the plenum and the duct, and a safety system. The controller is configured to monitor the performance of the variable speed fan and all filters within the duct and activate the safety system when a default air speed or temperature threshold is exceeded. The VDF can be configured to monitor the fan speed when there is a change of greater than or equal to 10% in the air flow through at least one filter. The controller is configured to shut down the variable speed fan and the grill when the air flow changes by more than 10%.

[0011] In another embodiment, the plenum forms an open space configured to allow airflow to expand, cool, and direct the airflow from the air inlet to the duct. The plenum forms upper and lower air compartments configured to create a vacuum effect at the air inlet, the plenum configured to allow large grease particles in the air entering the air inlet to condense and escape from the air and form droplets on the plenum walls. The plenum walls are sloped toward a grease collector located at the bottom of the grill. The air inlet, plenum, and blower are configured to achieve a 100% capture rate of visible smoke.

[0012] In yet another embodiment, the recirculating grill further comprises an elongated slot extending over most or all of the length of the cooktop, and the elongated slot is located below the air inlet. The air supply duct is connected to the blower and the air supply port, and the air supply port is configured to capture visible smoke above the cooktop from the other side of the cooktop and direct the visible smoke to the air inlet. The air inlet is positioned to overhang the slot to increase the depth of capture.

[0013] The present disclosure provides a controller for a grill and also includes a human machine interface (HMI) screen configured to display operating conditions and prompt the user of faults, diagnostics, required maintenance, and output instructions. In this embodiment, the VFD is configured to gradually increase the speed of the variable speed fan to a level that maintains appropriate air velocity and capture capacity until the filter reaches the end of its use cycle and the HMI notifies the user to replace the filter. The controller includes a wireless communication module configured to send instructions or status to a mobile device.

[0014] The present disclosure provides a method of operating a recirculating grill with a variable fan drive, comprising: (a) providing a recirculating grill as described above; (b) measuring airflow using an airflow sensor located in a duct and generating an input signal; (c) transmitting the input signal to a controller, wherein the controller is a programmable logic controller (PLC); (d) generating an output signal from the PLC; (e) adjusting the variable fan drive (VFD) in response to the output signal; and (f) adjusting the speed of the variable speed fan to ensure that the airflow is within a desired predetermined speed. The change in airflow corresponds to the efficiency and service life of the filter.

[0015] For the purpose of summarizing the present disclosure, certain aspects, advantages and novel features of the present disclosure are described herein. It should be understood that it is not necessary that all of these advantages can be achieved according to any one embodiment of the present disclosure. Therefore, the present disclosure can be implemented or executed in a manner that realizes or optimizes an advantage or a group of advantages taught herein, without necessarily realizing other advantages taught or suggested herein at the same time. Features of the present disclosure that are considered to be novel are specifically pointed out and clearly claimed for protection at the end 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings that accompany the text portion of this specification illustrate embodiments and methods of use of the invention constructed and operative in accordance with the teachings of the invention.

[0017] Figure 1A A top view of a recirculating grill of the present invention with an outer shell is shown.

[0018] Figure 1B Shows Figure 1A Front view of the recirculating grill.

[0019] Figure 1C Shows Figure 1A Isometric perspective view of a recirculating grill.

[0020] Figure 1D Shows Figure 1A Side view of a recirculating grill.

[0021] Figure 2A Shows Figures 1A-1D A top view of a recirculating grill without the housing exposing the airflow duct with the blower housing and blower fan.

[0022] Figure 2B Shows Figure 2A Front view of the exposed recirculation grill.

[0023] Figure 2C Shows Figure 2A An isometric perspective view of an exposed recirculating grill.

[0024] Figure 2D Shows Figure 2A Side view of the exposed recirculating grill.

[0025] Figure 3 1 is an exploded view of the recirculating grill of the present invention.

[0026] Figure 4A A top view of a recirculating grill having an elongated slot with its internal components exposed and being pulled out of the housing by a moving platform is shown.

[0027] Figure 4B Shows Figure 4A An isometric perspective view of an exposed recirculating grill.

[0028] Figure 5A The interior plenum of a recirculating grill of the present invention is shown.

[0029] Figure 5B A diffuser according to the invention is shown.

[0030] Fig. 6A A top view of a recirculating grill with an outer shell and an extended mobile platform used therewith is shown.

[0031] Figure 6B Shows Fig. 6A Front view of the recirculation grill with the mobile platform extended.

[0032] Figure 6C Shows Fig. 6A An isometric perspective view of the recirculating grill with the mobile platform extended.

[0033] Fig.6D Shows Fig. 6A Side view of the recirculation grill with the mobile platform extended.

[0034] Fig. 7A shows a modular frame segment Fig. 6A Exposed side view of the mobile platform.

[0035] Figure 7B Shows Fig. 7A The connecting parts of the modular frame of the mobile platform.

[0036] Figure 7C Shows Fig. 7A Modular bracket for mobile platforms.

[0037] Fig.7D Shows Fig. 7A Example side view of a modular bracket.

[0038] Fig. 8A A top view of a dining surface design associated with the recirculating grill of the present invention is shown.

[0039] Figure 8B Shows Fig. 8A Isometric perspective view of a recirculating grill.

[0040] Fig.9A A front view of a baffle filter for use with the recirculating grill of the present invention is shown.

[0041] Fig. 9B Shows Fig.9A An exploded side view of the components of a baffle filter.

[0042] Fig. 9C Shows Fig. 9B An isometric perspective view of an exploded view of the components.

[0043] Fig.9D A front view of a combined filter for use with the recirculating grill of the present invention is shown.

[0044] Fig.9E Shows Fig.9D Side view of the combined filter.

[0045] Fig.9F Shows Fig.9D Isometric perspective view of a combined filter.

[0046] Fig.10 A flow chart associated with a variable fan drive (VFD) for use with the recirculating grill of the present invention.

[0047] Fig.11A An isometric perspective view of a recirculating grill is shown having a baffle filter positioned at an angle within the duct of the recirculating grill of the present invention.

[0048] Fig. 11B for Fig.11A A side view of a recirculating grill is shown.

[0049] Various embodiments of the present invention will be described below with reference to the accompanying drawings, wherein like reference numerals represent like elements. DETAILED DESCRIPTION

[0050] The present application provides a recirculating grill having at least one or more of the following features: (i) a diffuser and internal plenum operable to improve airflow and grease control into the duct; (ii) a waste chute extending over the entire or majority of the length of the cooking surface and located below the air intake; (iii) a mobile platform for manipulating and improving accessibility to the internal components of the cooking unit for cleaning and repair; (iv) a variable fan drive (VFD) for improving the efficiency and control of airflow through the filter; and (v) a combination filter for improving waste handling, cleaning and replacement of the filter. The present disclosure provides a recirculating grill / grilling table that is movable and meets the specific requirements of compliance with UL / ETL safety standards. Improvements have been made to existing grills that relate to ease of use / maintenance, efficient heating characteristics, and low levels of noise / vibration to not interfere with the dining experience. This includes a grill / table that is modular and can be effectively disassembled for shipping and transportation.

[0051] The terms "grill" and "grilling station" are used interchangeably in the industry and throughout this specification. Typically, a commercial kitchen or teppanyaki-style restaurant will have one or more grills with a flat-top cooking surface heated by a plurality of electric or gas burners connected to a control knob for adjusting the cooking temperature. The grill / grilling station includes internal components located below the cooking surface. The grill / grilling station may include an outer shell that is sized and shaped to protect and conceal the internal components. If the grill / grilling station is movable, or is located in a restaurant seating area so that customers are seated close to it, additional safety precautions are required.

[0052] refer to Figures 1A-7D, shown is an exemplary cooking device or recirculating grill or grilling table 100. In this embodiment, grill 100 includes a cooktop 110, which is relatively flat above the interior of the grill. Cooktop 110 can be made of any material sufficient for cooking and easy to clean. In this embodiment, cooktop 110 is manufactured as a single plate made of stainless steel. Cooktop 110 can have a rectangular geometry with a length "L" along the long side and a width "W" along the short side. A user or cook / chef can obtain and manage the cooking of food in a front view position along the length L. For teppanyaki-style restaurants, customers are exposed to and watch the cooking of their food up close, and customers or guests can sit around the width W and on the opposite side of the front view. This is usually desirable because the experience of watching the chefs work is an important part of the entertainment and attraction of these restaurants.

[0053] The recirculating grill 100 includes internal components that support the cooktop 110, making it possible to capture the smoke generated by cooking. As shown in FIG. 1, the grill 100 is surrounded by side walls 115, a front cover 116, and a rear wall (not shown), thereby forming an enclosure. For safety and aesthetic purposes, these walls enclose the internal components and can also be used as mufflers to limit, reduce, and eliminate unwanted noise. Positioned along the cover 116 is a baffle filter door 118, which is removable to allow access to the duct 120 that accommodates one or more filters. In one embodiment, an optional controller 122 is positioned along the cover 116, which allows the user to control the heating of the cooktop 110, turn the grill 100 on and off, and provide basic diagnostic data visible on the corresponding screen. In one embodiment, the controller 122 includes touch screen control and compatibility with a digital display. In a further embodiment, the controller 122 can be programmable and include artificial intelligence and intelligent adaptability to adjust for specific uses, thereby expanding or improving grill efficiency and performance. This may include adjusting hot spots associated with cooking surfaces, as well as adjusting environmental conditions as certain components degrade.

[0054] The internal components of the grill 100 include a duct 120 and a blower housing 121. The duct 120 serves as a filter housing for housing a filter operable to filter smoke and airflow drawn from the cooktop 110. As food is cooked on the cooktop 110, smoke and exhaust gases are pushed by the air delivered through the air supply duct 119 and pulled into the air inlet 112. The smoke / air generated during use of the grill 100 is contaminated with grease and food particles and must be filtered before being released by the grill 100. The duct 120 surrounds the filters, which typically include baffle filters and auxiliary filters (see Figures 9-11). The air supply duct 119 is connected to a blower 128, which pushes air directly out of the air supply duct 129. The blower 128 produces low-speed air that is pushed toward the air inlet 112 to sweep across the cooktop. This forms an air curtain over the cooktop 110. The air curtain combined with the pull-type fan within the fan housing 121 prevents air contamination and allows for a 100% visible smoke capture rate.

[0055] The blower housing 121 encloses a blower fan 123 that draws air from the cooktop 110. The blower must be strong enough to pull air from the cooktop 110 into the air inlet 112 at a sufficient velocity and through the plenum 150 into the duct 120 where it is filtered before passing through the blower fan 123 and out of the grill 100. This air may be referred to as "recirculated air." The recirculated air is pushed downward and through the floor, exiting at the feet of the user. In one embodiment, a louvered vent 127 is positioned toward the front of the grill 100 to direct the air outward and downward as it exits. In one embodiment, the blower fan 123 includes an inlet ring that funnels the air into the blower to increase efficiency. The blower includes a centrifugal fan with a backward curve to create the airflow necessary to capture smoke.

[0056] To heat the cooktop 110, a plurality of electric heating elements 126 are located directly below the cooktop 110. In this embodiment, three heating elements 126 are provided to allow cooking or heating of the area on top of the cooktop 110. This allows the user to manage cooking food in a variety of ways by creating different temperature zones on the surface. For example, one area can be used to heat rice and vegetables, while another area can cook meat and fish at a much higher temperature. The heating element 126 is electrically coupled to an energy source (not shown) for delivering heat to the cooktop 110 and a control knob (not shown) for manually controlling the cooking surface temperature. In another embodiment, digital and intelligent control is used. Gas can also be used as a heat source and is within the scope of the present disclosure. The fire extinguishing nozzle 114 is located near the air inlet 112 and is directed to the cooktop 110. This is a safety measure that releases fire extinguishing chemicals when triggered by a fail-safe mechanism. Safety compliance requires the presence and function of the nozzle 114 and corresponding sensors throughout the interior of the grill 100. The safety sensor is configured to trigger the nozzle 114 when a predetermined temperature and / or pressure threshold is exceeded.

[0057] The grill 100 also includes a splash guard 113 disposed along the perimeter of the cooktop 110. The splash guard 113 is configured to reduce and prevent grease and food from falling or being pushed off the cooktop 10. This is particularly useful in a restaurant environment where customers are seated close to the cooking surface.

[0058] groove

[0059] In one embodiment, the grill 100 includes an elongated slot or "grease" slot 125 that is configured to extend in the length L of the cooktop 110. In one embodiment, the cooktop 110 is 48 inches in the length L, and the slot 125 extends over most or all of its length L. The slot 125 is formed in the opening along the front 116. This allows the user to push waste and food into the opening and capture it in the slot 125. The air intake 112 is located directly above the slot 125 and has holes or slats 152 along the back to capture smoke and exhaust from the cooking surface. Additional grease and particles carried in the air to be captured by the air intake 112 can be captured in the slot 125. The waste collected in the slot 125 is pushed into the waste bay 111, which is a drawer that can be opened from the front cover 116 of the grill 100. The waste drawer 111 collects food scraps and grease pushed into the slot by the user. The groove 125 allows for a shorter cooking surface relative to the air inlet 112 in the width W direction, thereby allowing the air curtain to completely block contaminated air from escaping from the cooktop surface. Because the groove 125 extends in the length L direction, it is easier for the user to remove waste from the cooktop 110. The groove 125 includes a downward slope that allows waste to flow to the waste drawer 111.

[0060] Additional internal components of the grill 100 include an electrical box 124, which may be located next to the blower housing 121 and houses the electronics and power connectors for most or all of the electrical components of the grill 100. These electrical components include the blower, heating elements, controllers, and sensors. A fire can 140 carries a fire extinguishing agent, which, when triggered, is delivered to the nozzle 114 through a fire line 141. In this embodiment, the fire can 140 is located on the opposite side of the blower housing 121 compared to the electrical box 124. A system release module 142 may also be provided, which is a mechanical system that releases the fire extinguishing agent when triggered. UL / ETL compliance requires both a sensor mechanism and a mechanical safety mechanism.

[0061] Pressure chamber and diffuser

[0062] Special attention Figure 5A and 5B , the present invention provides a plenum 150 having an open space structure configured to facilitate and promote efficient flow of air from the air inlet 112 to the duct 121. The plenum 150 connects the air inlet 112 to the duct 121. This is the initial route that the air follows when it is directed to the filtration system housed by the duct 121. The plenum utilizes a diffuser 151 to meet the safety requirement of having a distance of at least 18 inches from the cooking surface (cooktop 110) before contacting the first filter, which is achieved by forcing the air to flow around the diffuser 151. The diffuser 151 is configured to form a ramp structure downwardly and outwardly toward the plenum wall 153. In this embodiment, the diffuser includes a relatively flat or horizontal center section 1501 and two opposing ramp sections 1502, which slope downwardly and away from the plane AA defined by the center section 1501. In one embodiment, the ramped section 1502 extends toward the plenum wall 153 of the grill housing to direct airflow away from the center section 1501. The diffuser may further include a vertical end section 1503 to allow diffused air to flow downward to a lower portion of the plenum 150.

[0063] In one embodiment, the diffuser 151 is formed of metal, such as stainless steel, such as 304 stainless steel or 316 stainless steel, etc. The different segments can be welded together. In use, air enters through the air inlet 112, reaches the diffuser 151, and the diffuser 151 separates the air so that it moves away along the various segments 1502 in at least two different directions and moves toward the side wall 115. The physical presence formed by the diffuser 151 forces the air to move outward toward the plenum wall 153 before moving downward toward the duct 121. During this process, as the spatial volume of the plenum increases, the air expands and therefore cools rapidly, which forces larger particles to fall from the air before being filtered. This acts as a pre-filter for smoke or any gas that is recirculated through the grill 100. This diffused air must make a sharp turn around the diffuser 151, which causes excess grease to be thrown to the bottom of the plenum 150, where the grease will drain into the grease tray 154. As the grease laden air passes through the plenum 150, the grease naturally condenses on the outermost wall 153 due to the lower temperature of the metal. In one embodiment, the bottom of the plenum 150 is sloped downward along the discharge section 1504 of the wall 153 to allow gravity to drain the grease particles into the grease tray 154.

[0064] In this embodiment, the geometry of the plenum wall 153 is segmented, showing sharp connection points, rather than smooth curves. While both are contemplated within the scope of the present disclosure, the segmented curve design provides ease of manufacturing because the individual segments can be welded together. The plenum wall 153 is configured to direct and promote the flow of air and grease downward toward the bottom of the plenum 150.

[0065] The diffuser 151 effectively forms two air compartments, an upper plenum chamber 155 above the diffuser 151 and a lower plenum chamber 156 below the diffuser 151. These air compartments form a large ratio of the size of the compartment opening to the size of the cubic volume within the compartment. This creates a "vacuum" effect that is necessary for the air velocity to be generated at the air inlet 112 in order to achieve a 100% or near 100% visible smoke capture rate. The surface area across the air inlet 112 creates an air flow ratio, that is, a ratio of air velocity to air volume. This is balanced within the geometry of the plenum sidewalls 153 to ensure that a 100% visible smoke capture rate is achieved for a given size grill 100. The vacuum effect can be manipulated by allowing the air velocity to be manipulated by changing the surface area of ​​the air inlet 112, and by allowing the air volume to be varied by changing the shape of the plenum walls 153. As the volume decreases, the velocity increases. However, the increase in volume places higher demands on the fans and filters. Therefore, the balance of size and shape of the plenum 150 should be optimized to ensure that both the blower and smoke capture requirements are met.

[0066] The location of the waste drawer 111 should be suitable for the space requirements of the plenum 150, because the plenum surrounds the entire front of the grill 100. Therefore, the waste drawer 111 is not installed directly below the cooktop 110 like existing indoor cooking stations. In this embodiment, the waste drawer 111 is placed in the center of the plenum 150, extending through the plenum 150 to the underside of the cooktop 110. This takes advantage of the dead space created by the diffuser 151 to minimize the blocking effect on the airflow. In this embodiment, the diffuser 151 forms the top of the drawer 111.

[0067] Platform Design

[0068] The present invention further provides a mobile platform that is operable to achieve efficient and effective manipulation of the grill 100, and accessibility and cleaning of its internal components. In this embodiment, the mobile platform includes a fixed frame 130 that forms a structure for holding the cooktop 110 and some of its internal components. The fixed frame 130 is formed by modular frame segments 230, which have mounting slots 231 extending in the length direction of the modular frame 230. In this embodiment, each modular frame segment 230 has a relatively square cross-section and can be cut into any desired size. In one embodiment, the frame segment 230 is made of aluminum or any material that can be used to hold the table 100 and its components. The fixed frame 130 includes a horizontal frame segment 130 and a vertical frame segment 133. In this embodiment, the platform further includes wheels 117, which can be casters or the like. The wheels extend downward from the horizontal frame segment 130 and allow the entire grill 100 to be manually manipulated along a floor or flat surface. This meets the mobility required for each grill 100 unit, which improves cleaning, design, accessibility, etc.

[0069] The fixed frame 130 serves as a base frame. The mobile frame 131 is connected to the fixed frame 130 and can slide in and out of the fixed frame 130. In the closed configuration shown in FIG. 1 , the mobile frame 131 is entirely located within the fixed frame 130 and below the cooktop 110. In the open position, the internal components can be pulled out of the housing and exposed, such as Figure 3 , 4A , 4B, 6A, 6C, 6D and 7A. In these embodiments, the mobile frame 131 slides out and extends to allow access to internal components. The mobile frame 131 supports the piping system for the fire protection system, ducts and fan housing. In another embodiment, the electrical box is further located on the mobile frame 131. The mobile frame 131 can be composed of modular frame segments 230, just like the fixed frame 130. In this embodiment, the mobile frame 131 is further connected to a sliding drawer 132, which allows the mobile frame 131 to be moved to slide in and out of the guide rails.

[0070] Each end of each frame segment 230 may be covered by a connector 232. In this embodiment, the connector 232 forms four protrusions 233 defining channels 234 therebetween. Channels 234 allow the connector 232 to be mounted and connected to any other modular frame segment 232 by engagement of channels 231. Thus, a plurality of frame structures may be formed and designed for mounting and retaining the grilling station 100 and any of its corresponding components. This allows for improved customization and design.

[0071] In one example, the platform design consists of two parts: a mobile platform 131 and a fixed frame 130. The mobile platform 131 is connected to the fixed frame 130 by sliding on both sides of the grill 100 along the width W direction. When sliding to separate from each other, the fixed frame 130 supports the cooktop 110, the heating element 126, the electrical box 124, the thermocouple, the junction box and the air supply assembly 128. The mobile platform 131 supports the fan 123, the duct assembly 120 and the fire protection system components 140 / 141 / 142. In another embodiment, the electrical box is supported by the mobile frame. When the workbench 100 is opened, it is easy to reach the top of the duct 120 to reach and replace the filter. In addition, the electrical box 124 and the fire protection system components 140, 141 and 142 are located on the right and left sides of the mobile platform, respectively, and the heating element 126 is located below the cooktop 110, which also makes maintenance easier and more accessible.

[0072] The platform design allows for better access to internal components for cleaning, filter changes and maintenance. Due to the 710b safety requirement of at least 18 inches and the requirement for the grill height, the filters must be almost flush with the ground. In order to reach this area to clean or change the filters, it is generally necessary to crawl on the ground. In addition, since there needs to be electrical and fire protection space on both sides of the pipes, without the mobile platform described herein, there is no easy way to reach the pipes behind these systems. In addition, without the mobile platform of the present invention, the fire protection and electrical systems would need to be accessible from the ground. The present invention provides a grill that can be separated into two parts to allow access to the filters, electrical and fire protection systems from the top.

[0073] Isolating the electrical box with a fixed frame provides an improved electrical configuration. When the electrical box is fixed, a technician can reach most areas of the grill without modifying or touching the electrical box. This allows for fixed connection points from the electrical box to other components or power sources. The electrical box can include two multiplexers connected by coil cables. The fire protection system connection has its own coil cable.

[0074] When utilizing a mobile platform, the fire ducting, wiring between the moving parts, and fixing / leveling all need to be optimized. For the fire ducting, the fixed frame is moved further inwards to allow the fire ducting to extend to the plenum and to the cooktop. This allows the fire system to rest on the mobile platform. Wiring between the moving parts is solved by using coiled cables that return to a spring-like shape when not extended. Leveling is achieved by placing the frame on leveling casters that include legs and wheels. For safety, the platform is attached to the frame by sliders that can well withstand the weight of the platform. This allows the platform to withstand unforeseen situations where additional weight is applied to the platform, such as a person leaning on the plenum.

[0075] FIG. 8 shows an exemplary grill 100 having an eating or dining surface 300 surrounding a cooktop 110. Because the grill 100 is movable and portable, a variety of dining surface designs can be implemented. In one embodiment, the surface 300 is relatively square. However, other geometric shapes are also contemplated within the scope of the present disclosure, such as circular and rectangular. The dining surface 300 can be movable with the grill 100, or fixed to allow the grill 100 to be moved in and out of the surface. It is further contemplated that the dining surface 300 can implement a variety of materials and aesthetic designs.

[0076] Filter Design and Variable Fan Drives

[0077] Previous models have struggled to address the high cost of ownership issue due to the labor costs associated with cleaning the electrostatic precipitator (ESP) filters with the proper procedures and frequency. The training costs for employees to maintain and clean these units are relatively high. If not handled properly, the ESP can easily become damaged and cause failures. The present invention provides a grill that uses passive filters. In one embodiment, the passive filters include a MERV (minimum efficiency reporting value) type filter, such as a Merv 15 and odor control combination filter (combination filter) and a wool baffle filter. These passive filters are disposable and are replaced when they are completely saturated with grease. In addition, the internal compartments that need to be cleaned are designed to be easily accessible to reduce cleaning time. The use of passive filters can increase static pressure compared to the use of an electrostatic precipitator (ESP). However, utilizing a variable fan drive (VFD) that controls the fan speed (see Fig.10Flow chart), filter life can be increased. In one embodiment, the VFD can monitor airflow changes up to 10% (if airflow changes by more than 10%, the device shuts down) in accordance with UL / ETL standards. This filter arrangement can provide 100% visible smoke capture, which is required for smoke capture, and provide vapor grease content of less than 5ppm (parts per million) measured at the exhaust port under EPA test conditions. This creates contradictory requirements: minimum air velocity for proper filtration, and high air velocity for smoke capture.

[0078] Referring to Figures 9-11, the present invention provides a disposable combination filter 500. The combination filter works in conjunction with a wool covered baffle filter 400. A variable speed fan is used instead of a constant speed fan to extend the life of the filter. The wool baffle filter 400 includes a frame 410 that holds a wool insert 412 and a baffle filter 414 together. The baffle filter 414 can be removed and cleaned. The wool baffle filter 400 will first capture large grease particles that make up most of the grease entering the system (grill table 100). The wool cover 412 on the filter 400 is also disposable and should be replaced as needed. Remaining airborne grease will be collected on the combination filter 500.

[0079] The combination filter 500 consists of two different filters 512 and 514 in one package. The first is a MERV filter 512 that collects physical airborne grease. The second is a carbon filter 514. The carbon filter 514 will adsorb odor-causing particles. According to the 710B specification, if the airflow changes by more than 10%, the recirculation device must be shut down and each filter may need to be tested. The variable fan drive (VFD) can increase its speed to maintain air velocity as the filter gradually becomes saturated. Due to the nature of MERV filters, the filtration efficiency gradually increases as the filter gradually becomes saturated, so there is no risk of losing capture when the fan speed is increased. This allows the filter to be used throughout the life of the filter without the need for replacement due to airflow specification requirements. To address the testing problem, the combination filter 500 is specifically designed for user convenience and to limit the amount of testing required.

[0080] Previous systems utilized electrostatic precipitators, or ESPs. ESPs present issues related to cleaning and reliability. For safety reasons, the ESP can only be operated by professionals because it is a high voltage component. Additionally, improper handling of the ESP often damages the internal circuit boards / batteries. When the battery is bent or damaged, the ESP will short-circuit the power pack, causing the unit to malfunction. Since the ESP must be cleaned frequently, damage is very likely to occur if it is not handled by a professional.

[0081] Another challenge with filtration involves the given space for the actual filter. Filter efficiency depends on the length of time it takes the air carrying the grease to pass through the filter. Two ways to accomplish this are to slow the air velocity or to increase the depth of the filter. To address this issue, the airflow is blocked and the baffle filter 400 is positioned at an angle within the duct 120 (see FIG. 11 ) to increase the available depth of the duct 120.

[0082] Fig.10 A flow chart of a variable fan drive process 600 is shown. In this example, process 600 begins at block 610 where airflow is measured by an airflow sensor. At block 620, the airflow sensor generates an input signal. At block 630, a programmable logic controller (PLC) receives the input signal of block 620. This generates an output signal at block 640, and the process then proceeds to block 650 to adjust a variable fan drive (VFD). Then, at block 660, the VFD drives the fan speed to adjust accordingly.

[0083] Eliminating and reducing odors is a problem that needs to be solved when using a recirculating grill or any indoor restaurant environment. Therefore, in another embodiment, a final filter is configured in the airflow path after the air has been cleaned by the baffle filter and the combination filter. This final filter can include a filter material with a relatively large surface area to capture and / or eliminate any residual odor particles, such as fatty acids from meat. In another embodiment, the final filter is specifically designed to eliminate odors generated by the cooking of steak / beef, seafood, poultry, vegetables, rice and cooking oils.

[0084] The present invention provides a recirculating grill / grill that utilizes a slot 125 to collect grease by draining it into the interior of the grill 100. If the slot 125 is located directly in front of the air inlet 112, this will increase the distance required to capture the smoke. Therefore, this disadvantage is overcome by having the air inlet 112 suspended above the slot 125 to increase the capture depth. In addition, the airflow can be optimized by adjusting the configuration of the filter 400 / 500 to obtain an acceptable air velocity for capturing smoke, while balancing the ratio of air velocity to volume to create a vacuum effect. The addition of an air supply port 119 and a blower 128 on the other side of the cooktop 110 opposite the air inlet 112 can capture air, which results in additional capture and prevents air from escaping the grill. This results in entraining air in the direction of the air inlet 112, which helps capture smoke.

[0085] Service costs can also be reduced using a grill according to the present invention. Previous models did not have indicators to diagnose technical problems. For example, the ESP often malfunctioned due to lack of cleaning. Without proper cleaning, large amounts of grease / debris can build up on the ESP, causing an electrical short. If corrective action is not taken, the power pack will enter a safe mode and result in a loss of filtration efficiency and smoke capture rate. The present disclosure combines an indicator on the fuse, a highlighted short circuit indicator, and an intelligent system that alerts the user through a human machine interface (HMI) screen to resolve specific faults and output instructions.

[0086] The present invention provides a grill / grilling table with standard dimensions that match other units in most kitchens. In one embodiment, the grill / grilling table of the present invention meets the standard specifications of kitchen floor space: 30 inches (height) × 50 inches (length) × 33 inches (width).

[0087] The present invention provides a lightweight, compact mobile grill / barbecue that can be easily moved around and through doors without extra labor. By using cast aluminum heaters, the mounting plate is eliminated, thereby reducing the weight of the barbecuing station. Further, the change from mild steel to extruded aluminum significantly contributes to the weight reduction. Extruded aluminum not only has the advantage of weight reduction, but also enables modular design. Extruded aluminum parts and their subsystems can be disassembled by bolts for field replacement without the need for specialized knowledge. Therefore, it can reduce service costs. In addition, transportation is simplified because the frame can be partially pre-assembled.

[0088] The present invention provides user-friendly features, including ease of use / maintenance. Unlike limited automatic temperature controllers ("ATC"), the grill of the present disclosure utilizes an advanced HMI (smart) system display that provides diagnostic information to the end user. These messages can remind the user to change filters, replace fuses, or pay attention to active shorts. It reduces a lot of downtime and maintenance costs. Another advantage includes the maintenance level of cleaning and filter replacement. As previously mentioned, in the cost of ownership, the use of passive filters with VFDs eliminates the need for cleaning of the main active filters. As the filters gradually become clogged with grease, the VFD gradually increases the fan speed to a level that can maintain proper air velocity and smoke capture. This situation continues until the filter reaches its "end of life cycle" and then the HMI notifies the user to replace the filter.

[0089] Further, the mobile platform allows the filters, air intake and fire protection system to be located on the mobile platform, which is housed within a fixed frame that supports the electrical system, air supply system and cooktop. This allows the mobile platform to be unfolded so that the filter ducts and other essential systems can be easily accessed for maintenance services. For filter replacement, the simple steps of opening the duct door, discarding the old filter and sliding in the new filter can be easily performed. After the safety device is properly locked and the mobile platform is returned to its original position, the unit can be turned back on and operated.

[0090] Important aspects of foodservice cooking appliances are their reliability and efficient heating characteristics, including heat-up / recovery speeds. A common criticism of appliances is that temperature capabilities are often not comparable to gas powered units. Achieving and maintaining adequate heat can be a significant challenge as the available amperage must be divided between cooking and the built-in recirculating hood system. In one embodiment, to enhance heating capabilities, the present disclosure provides a 50 amp cooktop subunit, thereby increasing the available amperage. In one embodiment, a clad cooktop is provided. A clad cooktop is a combination of aluminum, steel, and other layered metals to enhance heat transfer characteristics. Aluminum has properties that increase heat transfer and reduce heat recovery time. The cast aluminum heating assembly also covers a larger area of ​​the cooktop base, creating a more uniform edge-to-edge heating characteristic.

[0091] The present invention provides a grill with the function of reducing and eliminating sound and vibration. For recirculating grills, the operation of the motor and the airflow generated by the fan will generate higher levels of sound and vibration. Air leaks / cracks caused by improper manufacturing processes will cause high-pitched whistling sounds to be sensed. In one embodiment, the exhaust air is discharged into the grill itself based on the idea that the increase in the size of the muffler will reduce the pitch. A higher pitch sounds more annoying than a lower pitch of the same decibel level. Since a traditional muffler is not used, the grill is surrounded by a double layer of corrugated plate, thereby muffling the sound generated from within the grill. In addition, the fan and all moving parts can be fixed with appropriate gaskets to produce the lowest possible sound and vibration levels. The inner wall surface of the grill effectively acts as a muffler, which acts on the exhaust air. With a large amount of exhaust air leaving the grill in any direction from a position below the frame, the exhaust air is directed to a specific area to control turbulence and entrainment. To achieve this, a kick plate is provided around the grill to prevent air leakage, and a louver panel and diffuser are added to the plenum to direct the exhaust air at a downward angle.

[0092] The present invention may utilize the following: a mobile platform coupled to a fixed frame; using a passive filter in conjunction with a VFD to maintain the lowest possible air velocity for capturing smoke; utilizing the external frame itself as a muffler to address acoustic and spatial issues; providing slots in front of the air intake of the recirculation system; and placing baffle filters at an angle.

[0093] It should be noted that the steps described in the method of use can be performed in a variety of different orders according to user preferences. In the claims herein, the term "step of..." should not be interpreted as "step for..." and is not intended to trigger the provisions of 35 U.S.C. §112(f). When reading this specification, it should be understood that, where appropriate, taking into account matters such as design preferences, user preferences, market preferences, costs, structural requirements, available materials, technological advances, etc., it may be sufficient to adopt other settings of the method of use, such as different orders of the steps listed above, deleting or adding certain steps, including or excluding certain maintenance steps, etc.

[0094] The embodiments of the invention described herein are exemplary embodiments, and a variety of modifications, variations, and rearrangements are readily conceivable to achieve substantially equivalent results, all of which are included within the spirit and scope of the invention. In addition, the purpose of the foregoing summary is to enable the U.S. Patent and Trademark Office and the general public, especially scientists, engineers, and practitioners in the field who are not familiar with patent or legal terms or wording, to quickly determine the nature and essence of the technical disclosure of the application through a cursory glance.

Claims

1. A recirculating grill comprising: (a) Cooking stove; (b) an air intake having a plurality of slats and configured to draw air and smoke from the cooktop; (c) an internal plenum defined by plenum walls within the housing of the grill, the plenum walls being configured to direct airflow within the internal plenum; (d) a diffuser positioned below the air inlet within the plenum to form a structure having at least two ramp sections angled downward and outward in two opposite directions toward the plenum wall, wherein the diffuser is configured to divert air to move in at least two opposite directions away from a central portion of the plenum; (e) a duct for receiving at least one filter configured to capture unwanted particles from air and smoke from the plenum; (f) a fan housing enclosing a variable speed fan configured to adjust air speed in response to a variable fan drive (VFD) and a control process, the variable speed fan configured to pull air and smoke from the cooktop into the air inlet and through the plenum into the duct; and (g) a controller connected to the VFD, the controller configured to adjust a fan speed of the blower to regulate filter usage.

2. The recirculating grill of claim 1, wherein: The at least one filter comprises a wool baffle filter.

3. The recirculating grill of claim 2 further comprising a combination disposable filter located downstream of the wool baffle filter, the combination disposable filter comprising a carbon filter and a Minimum Efficiency Reporting Value (MERV) rated filter, wherein the combination disposable filter is provided as a single unit.

4. The recirculating grill of claim 3, wherein: The combined disposable filter is configured to provide 100% visible fume capture from the cooktop and a vapor grease content of less than 5 parts per million measured at the exhaust port.

5. The recirculating grill of claim 4, wherein: The baffle filter is positioned at an inclined angle within the duct and is configured to form a barrier to air flow before the air flow contacts the combined disposable filter.

6. The recirculating grill of claim 3, wherein: The controller is connected to a heating unit positioned below the cooktop, a variable speed blower, the VFD, a plurality of air flow and temperature sensors located inside the plenum and ducts, and a safety system including a fire extinguishing nozzle.

7. The recirculating grill of claim 6, wherein: The controller is configured to monitor the performance of the variable speed blower and the combination disposable filter and the wool baffle filter and activate the safety system when a default wind speed or temperature threshold is exceeded.

8. The recirculating grill of claim 1 further comprising an odor control elimination tail filter.

9. The recirculating grill of claim 1, wherein: The VFD is configured to respond to an air flow sensor configured to monitor a blower fan speed when air flow through the at least one filter changes by greater than or equal to 10%.

10. The recirculating grill of claim 9, wherein: The controller is configured to shut down the variable speed blower and the grill if the air flow changes by more than 10%.

11. The recirculating grill of claim 1, wherein: The plenum forms an open space configured to allow airflow to expand, cool, and direct the airflow from the air inlet to the duct.

12. The recirculating grill of claim 1, wherein: The plenum forms upper and lower air compartments, the plenum walls being configured to allow large grease particles in the air entering the air inlet to condense and escape from the air and form droplets on the plenum walls, and wherein the plenum walls are sloped toward a grease collector located at a bottom of the grill.

13. The recirculating grill of claim 1, wherein the air inlet, plenum, and variable speed blower are configured to achieve a 100% capture rate of visible smoke.

14. The recirculating grill of claim 1 further comprising an elongated slot extending for most or all of the length of the cooktop and located below the air inlet.

15. The recirculation grill of claim 1, further comprising an air supply duct connected to the blower and an air supply port, the air supply port being configured to capture visible smoke above the cooktop from the other side of the cooktop and guide the visible smoke to the air inlet.

16. The recirculating grill of claim 1, wherein: The air inlet is positioned to hang above the trough to increase the depth of capture.

17. The recirculating grill of claim 7, wherein: The controller also includes a human machine interface (HMI) screen configured to display operating conditions and alert a user to faults, diagnostics, required maintenance, and output instructions.

18. The recirculating grill of claim 17, wherein: The VFD is configured to gradually increase the speed of the variable speed blower to a level that maintains adequate airflow rate and capture capacity until the combined disposable filter reaches the end of its use cycle and the HMI notifies the user to replace the combined disposable filter.

19. The recirculating grill of claim 1, wherein: The controller includes a wireless communication module configured to send instructions or status to a mobile device.

20. A method of operating a recirculating grill having a variable fan drive, comprising: (a) providing the recirculating grill of claim 1; (b) measuring the airflow using an airflow sensor located in the duct and generating an input signal; (c) transmitting the input signal to the controller, wherein the controller is a programmable logic controller (PLC); (d) generating an output signal from the PLC; (e) adjusting the VFD in response to the output signal; and (f) Adjust the speed of the variable speed fan to ensure that the air flow is within the required predetermined speed; The change in airflow corresponds to the efficiency and life cycle of the filter.

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