Recirculation Grill Air Curtain and VFD for Smoke Capture
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Solution Overview
Problem
Traditional indoor grills require expensive and inflexible ventilation systems, leading to incomplete smoke capture, odor pollution, and limited design flexibility in commercial settings, while recirculation grills face challenges in meeting UL/ETL safety standards for smoke and fire safety.
Innovation Solution
A recirculation grill with a cooktop supported by a stationary frame, featuring an intake aperture with slats, an interior plenum for vacuum force creation, a diffuser, a filter tunnel with variable speed blower fan, and a controller for adjusting airflow and filter efficiency, along with a mobile platform for ease of use and maintenance, ensuring 100% smoke capture and compliance with safety standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional overhead ventilation hoods are used, then smoke capture is attempted, but the system is expensive, stationary, and fails to achieve significant smoke capture
Solution Approach 1:
Instead of using overhead hoods to pull smoke upward, the patent inverts the approach by using side-mounted intakes that pull smoke horizontally across the cooktop surface. The air curtain generated by the blower creates a visible smoke capture plane that redirects smoke laterally into the intake aperture, achieving 100% capture without overhead structures.
Solution Approach 2:
The patent employs pneumatic principles by using a blower to generate a high-velocity air curtain that acts as a fluid barrier to capture and redirect smoke. The air curtain creates a pressure differential that pulls smoke across the cooktop surface and into the intake, replacing mechanical overhead hoods with a pneumatic smoke capture system.
2Adaptability or versatility
If recirculation grills are used to avoid overhead ventilation, then design flexibility improves, but UL/ETL safety certification becomes difficult to achieve
Solution Approach 1:
The patent incorporates multiple sensors (smoke detectors, heat sensors, airflow sensors) that provide real-time feedback to the control system. When smoke or heat thresholds are exceeded, or when the air curtain velocity drops below required levels, the system automatically responds by adjusting the blower speed or shutting down, ensuring continuous compliance with UL/ETL safety standards.
Solution Approach 2:
The patent uses a variable speed blower controlled by a VFD that dynamically adjusts airflow velocity to maintain the air curtain at optimal levels. This dynamic control ensures the recirculation system consistently achieves 100% smoke capture and maintains safety certification requirements under varying cooking conditions, replacing static traditional systems.
3Object-affected harmful factors
If filters are added to capture grease and particles, then air quality improves, but airflow resistance increases and system efficiency decreases
Solution Approach 1:
The patent positions the air curtain to capture smoke and grease particles before they enter the recirculation system. By pre-cleaning the air stream at the intake aperture, fewer particles reach the filters, reducing filter loading and maintaining airflow efficiency. The diffuser further preconditions the airflow to reduce turbulence and filter resistance.
Solution Approach 2:
The VFD dynamically adjusts blower speed to compensate for filter resistance buildup over time. As filters become loaded, the system increases blower velocity to maintain required airflow and air curtain effectiveness, ensuring continuous optimal performance without manual intervention until filter replacement is needed.
4Ease of operation
If the grill is made mobile for ease of maintenance, then accessibility improves, but structural stability and safety code compliance become more difficult
Solution Approach 1:
The patent divides the grill into modular segments: a stationary frame containing the cooktop, heating elements, and safety systems; and a mobile platform containing the blower, filters, and control systems. This segmentation allows the mobile portion to be easily removed for maintenance while the stationary portion remains fixed to meet safety code requirements for structural stability and fire suppression systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves 100% visible smoke capture, reduces odor pollution, and enhances design flexibility and ease of maintenance, while meeting UL/ETL safety standards, improving the overall dining experience and operational efficiency.
Implementation Method 1
an interior plenum configured to create a vacuum force to pull air and smoke from the cooktop into the intake aperture
Implementation Method 2
a tunnel housing at least a filter configured to capture undesired particles from recirculating air and smoke from the plenum
Implementation Method 3
a blower housing enclosing a variable speed blower fan configured for adjusting velocity in response to a variable fan drive (VFD)
Data Source
AI summary
A recirculation grill that includes a cooktop and an intake aperture defining a plurality of slats configured for receiving smoke from the cooktop; an interior plenum configured to create a vacuum force to pull air and smoke from the cooktop into the intake aperture; a diffuser positioned within the plenum and extending downwardly and outwardly; a tunnel configured to receive air flow from the plenum and having at least a filter; a blower housing enclosing a variable speed blower fan configured for pulling air and smoke from the cooktop into the intake aperture and through the plenum and into the tunnel; and a variable fan drive (VFD) for controlling the variable speed blower fan and improving the life of the filter. The intake aperture, the plenum, and the blower are configured to achieve 100% visible smoke capture.