Steam system for continuous cleaning of hood fan

Abstract

A device and method for cleaning fans in range or stove hoods by spraying steam onto the fan impeller area on which soot and cooking fumes condense to clean the impeller and wash the accumulated condensates down a drain. By using steam above atmospheric pressure as the cleaning fluid, the device uses significantly less water that other devices that spray water or an aqueous solution to clean the fan blades.

1 . A hood for ventilating a cooking area, comprising:
 a hood enclosure;   a fan disposed in the enclosure for exhausting cooking fumes, the fan having a fan housing; and   a steam generator for generating pressurized steam from a water supply, the steam generator having an outlet, and the outlet being fluidly connected to the fan housing effective to direct steam onto the impeller of the fan, the steam pressure being above atmospheric.   
   
   
       2 . The hood of  claim 1 , further comprising
 a steam generator housing having a mating base and cover enclosing the steam generator, and   a pump mounted on the steam generator housing and fluidly connected between the water supply and the steam generator.   
   
   
       3 . The hood of  claim 1 , wherein the steam generator further comprises a heating coil and at least temperature regulator for controlling the temperature at which the heating coil shuts off. 
   
   
       4 . The hood of  claim 3 , further comprising a second temperature regulator controlling the temperature at which the heating coil is turned on. 
   
   
       5 . The hood of  claim 4 , further comprising a temperature-sensitive fuse controlling power to the induction heating coil by sensing the temperature of the steam generator. 
   
   
       6 . The hood of  claim 3 , wherein the steam generator comprises a base and a cover, said heating coil is disposed in the base, and a plate having a plurality of small holes and disposed immovably between the base and the cover. 
   
   
       7 . The hood of  claim 1 , further comprising a user-accessible controller for initiating a cleaning cycle, the controller including a timer, and the controller energizing the pump and the heating coil during the cleaning cycle. 
   
   
       8 . The hood of  claim 7 , further comprising a water reservoir attached to the hood and fluidly connected to the steam generator, and a low level sensor connected to the controller. 
   
   
       9 . A method for degreasing the impeller of a fan mounted in a cooking exhaust hood, comprising:
 A. providing a hood installation including said fan;   B. providing water and heating the water to steam in a vessel to generate steam above atmospheric pressure; and   C. directing said steam from said vessel against the impeller of said fan in an amount effective to degrease the impeller.   
   
   
       10 . The method of  claim 9 , wherein the pressurized steam is generated at a temperature of at least about 120° C. 
   
   
       11 . The method of  claim 10 , wherein the pressurized steam is generated at a temperature of at least about 145° C. 
   
   
       12 . The method of  claim 10 , wherein the pressurized steam is generated up to a temperature of about 200° C. 
   
   
       13 . The method of  claim 9 , further comprising the step of stopping the heating when the temperature of the steam generated exceeds about 215° C. 
   
   
       14 . The method of  claim 9 , further comprising pumping water to said vessel. 
   
   
       15 . The method of  claim 9 , further comprising restricting the flow of steam from said vessel onto said impeller with a nozzle. 
   
   
       16 . In a device for cleaning the impeller of a fan installed in a hood ventilating a cooking area, said device directing a fluid onto the impeller and draining a liquid from the impeller, the improvement comprising a steam generator for generating steam as said fluid and directed steam onto the impeller. 
   
   
       17 . The method of  claim 9 , further comprising providing a refillable reservoir of water, and providing the water by pumping the water from the reservoir, and further comprising automatically shutting off the steam generator if water in the reservoir falls below a predetermined level.