Abstract:
The subject of this patent application is an improved method for extracting grease and heat from the exhaust air over cooking equipment. This invention collects more grease than other grease baffle filters by combining principles of vapor condensation and centrifugal particulate separation. It converts waste heat into usable heat. It cools exhaust temperatures and reduces humidity on recirculating hood systems. It has self-cleaning capabilities using in-line heated water. It is programmable for automatic operation and performance monitoring. And it can be used with nearly any standard existing or new commercial kitchen exhaust hood as a replacement for the standard grease baffle filter.

Description:
DESCRIPTION OF THE DRAWINGS 
       [0001]      FIG. 1  is a representation of relation between the water paths and various parts of the system, cooking range and hood, and hot water heater. 
         [0002]      FIG. 2  shows an exploded view of the actual filter to be installed in the existing exhaust hood. 
         [0003]      FIG. 3  shows front, side, and top views of the actual filter to be installed in the existing exhaust hood. 
         [0004]      FIG. 4  shows an “end on” view of the finned conduits and diagrams the intended airflow through the filter. 
         [0005]      FIG. 5  is a schematic of the path of the water through the system when the system is in “Cool Mode”. 
         [0006]      FIG. 6  is a schematic of the path of the water through the system when the system is in “Clean Mode”. 
         [0007]      FIG. 7  is a schematic of the path of the water through the system when the system is in “Bypass Mode”. 
         [0008]      FIG. 8  is a schematic of the path of the water through the system with a heat exchanger. 
     
    
     DETAILED DESCRIPTION 
       [0009]    This invention may include: one or more filters ( 100 ), tubes to connect the filters in series,  3 -way valves or one 6-way valve ( 30 ), valve Timer, performance monitoring system, pressure bypass valve ( 60 ) and plumbing fittings to connect the filters and valves between the cold water supply and the water heater. 
         [0010]    Plumbing connections should be made as shown in  FIG. 1 . The invention is placed in the exhaust hood, replacing an existing grease baffle filter ( 100 ). 
         [0011]    In “Cool Mode” most water will come from the cool water supply line ( 65 ) through a Control Valve ( 30 ). During high demand for hot water, some water might flow through the Pressure Bypass Valve ( 60 ) directly to the water heater to meet the high demand. Otherwise the water flows through the Connector Tubes ( 75 ), through the Connector ( 70 ) and through the first half of the Upper or Lower Manifold ( 50 ) where the Baffle ( 45 ) directs it through Manifold&#39;s Faceplate ( 40 ), into the Finned Conduits ( 55 ), through the opposite Manifold ( 50 ) and back down through the other Finned Conduits ( 55 ) to the second half of the Upper or Lower Manifold ( 50 ). The warm water then exits the filter through the second connector ( 70 ), through the Connector Tubes ( 75 ) and either into the neighboring filter or out to a Control Valve ( 30 ) and to the water heater inlet ( 20 ), as shown in  FIG. 5 . 
         [0012]    In the “Clean Mode” the cool water supply ( 65 ) is directed by the Control Valve ( 30 ) to the water heater ( 80 ), out to the Control Valve ( 30 ) and into the Upper or Lower Manifold ( 50 ). It is then directed up through the Finned Conduits ( 55 ) by the Baffle ( 45 ) and out through the other side of the filter ( 100 ) and through a Control Valve ( 30 ) to the hot water demand in the Kitchen ( 35 ), as shown in  FIG. 6 . 
       Function 
       [0013]    This invention functions in two modes. The first mode is for filtering and cooling the hot, grease- laden fumes produced by commercial cooking appliances during normal kitchen operation. The cooling process is accomplished by circulating cool water (from the city supply) ( 65 ) through the inside of the Finned Conduits ( 55 ) of the filter while the exhaust hood fan draws the hot air ( 75 ) through the outer surface of the Finned Conduits ( 55 ) of the filter as shown in  FIG. 4 . The heat transfers from the air to the Finned Conduits ( 55 ) then into the flowing water, thus substantially reducing the exhaust air temperature while increasing the temperature of the water. (This is most beneficial when used with recirculating hood systems that return exhaust air back to the kitchen after passing through the filtration system.) The water flows when a demand for hot water is created in the kitchen. The heated water then enters the kitchen water heater ( 80 ), thus reducing its required energy for operation. Refer to  FIG. 4 . 
         [0014]    The filtering of the air is accomplished by a combination of centrifugal particulate separation (used by most common grease baffle filters) and vapor condensation (which is a new principle for this application). The unique shape of the Finned Conduits ( 55 ) cause the air to accelerate as it passes through the serpentine passage ways which causes air-born particulate matter to contact and adhere to the cold metal, separating it from the air. 
         [0015]    The cold water flowing through the filter keeps the metal Finned Conduits ( 55 ) cool and causes the grease vapor and water vapor to condense out of the air and drip down the Finned Conduits into an existing Grease Tray below the filter, leaving the air dryer and cleaner than other filters would. This improved filtration system extends the life of the costly fabric pre-filters and HEPA filters, usually installed downstream of the baffle filters on recirculating systems. It also allows larger air passages in the filter, thus reducing the load on the exhaust fan, resulting in reduced power consumption. On hoods that exhaust to the outside environment, the improved vapor removal will reduce the need for frequent cleaning of the exhaust flue. 
         [0016]    Since the process of condensation is exothermic, the phase change from vapor to liquid efficiently releases heat from the air into the water flowing through the filter, which causes the filter to act as a pre-heater for the main water heater. 
         [0017]    The second mode of operation is for self-cleaning. This would normally occur every day after the kitchen is closed, the exhaust hood is turned off and the dishwasher is running. A single 6-way valve or a series of valves ( 30 ) as shown in  FIG. 1  will enable water to flow from the outlet of the water heater ( 25 ) through the filter ( 100 ) and to a hot water demand in the kitchen ( 35 ), i.e. dishwasher. As the heated water passes through the filter ( 100 ) the heat transfers to the Finned Conduits ( 55 ) and into the grease causing it to melt and drip into the existing Grease Tray below, leaving the filter clean and ready for use the following day. The heated water is not dumped down the drain as it is when other filters are cleaned by hand, and the grease never coats the sink or clogs the drain or has to be separated from drain water. Instead, the grease collects automatically in the existing grease tray and remains separate for easy disposal. The water used for cleaning the grease from this invention flows through the internal water passages of the filter&#39;s Finned Conduits ( 55 ), and then goes to a hot water demand in the kitchen for its final use, thus drastically reducing energy and water consumption in the cleaning process. 
         [0018]    The preferred embodiment employs a motorized 6-way valve and a Timer that can be programmed to operate automatically to cool during operating hours and to clean after hours, or to cycle at any frequency that the operator requires. 
         [0019]    A second embodiment employs a water-to-water heat exchanger to permit closed-loop operation, isolating the fluid in the filter from the water supply to the kitchen (see  FIG. 8 ). 
         [0020]    Performance of the invention may be monitored and displayed by a data acquisition system. Differential temperature and flow rate will determine the amount of saved energy, which could be converted to an estimated cost savings and report it on a local monitor.