Abstract:
An exhaust hood having an inverted V-shaped interior, the walls comprising the inverted V including grease filters and the apex of the inverted V lying adjacent to an exhaust duct to be placed in communication with an exhaust fan. The interior of the hood thus being shaped like an inverted funnel, rising gases and entrained contaminants are directed to the grease filters and thence to the exhaust duct.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an exhaust hood for moving air laden with grease, smoke, vapors, or other contaminants or particulates from a working environment, and more specifically, to such an exhaust hood having an inverted V-shaped transverse configuration for more efficiently funneling the contaminated air from the working environment. 
     2. Related Art 
     Exhaust hoods are employed in a variety of environments such as kitchens, laboratories, and commercial food-preparation spaces, in which there are typically several cooking units aligned in a row. Some of these units; e.g., boilers and fryers, may produce considerable quantities of smoke, fumes, grease particles and moisture, while other units, e.g., ranges and griddles, may generate pollutants in substantially smaller amounts. Kitchen exhaust ventilation systems have traditionally been designed with enough airflow capacity to remove pollutants from broilers, fryers, and more active pollution-generating cooking units. 
     Because of the amount of negative pressure necessary to remove a large volume of contaminants, operating these exhaust ventilators is costly. More particularly, most island-type commercial exhaust hoods having a grease filtering capability include a grease filter installed in the center of the hood cavity at approximately 45° from horizontal in a V-shape having a downwardly directed apex and running the full length of the hood. This configuration is shown as FIG. 1, labeled Prior Art. The principal of operation of this prior art configuration is to create enough negative air pressure in front of the filter in order to capture the heat, smoke, grease and other airborne contaminants and remove them from the working environment. 
     The negative air pressure downstream of these grease filters must be substantial enough to alter the vertical direction of the hot contaminated air created in the cooking process and draw it toward and then into the grease filters. Failure to exhaust sufficient volumes of air through the filters will result in some hot contaminated air becoming trapped in the hood cavity rather than being exhausted through the filters. Once the hood cavity is filled with the hot, vertically rising, contaminated air that has not been captured by the grease filters, it will begin to escape around the lower edges of the hood into the room or other working space. 
     The prior-art solution for the foregoing problem, which is commonplace in island-type food preparation surfaces, is to exhaust larger quantities of air through the grease filters until the negative air pressure created is high enough to alter the direction of the vertical air flow toward the grease filter. This requires an exhaust fan; a motor; and a heating, ventilation, and air conditioning (“HVAC”) system capable of handling a larger volume of airflow, which, consequently, means higher construction cost when installing the system and higher utility costs when operating the system. 
     What has been needed is a more efficiently and economically designed hood requiring a smaller or less powerful exhaust fan, motor, and HVAC system, yet providing effective exhaustion of contaminated air. 
     SUMMARY OF THE INVENTION 
     In its broader aspects, the present invention provides an exhaust hood comprising a housing having a pair of opposing end panels and an open underside. Interior surfaces form an inverted V in transverse section, the interior surfaces and the end panels defining a cavity extending upwardly within the housing from the open underside. At least one filter provides at least a portion of the interior surfaces. An exhaust outlet is formed in the housing above the apex of the inverted V formed by the interior walls, the exhaust outlet being in fluid communication with the cavity by way of the filter. The cavity and the exhaust outlet thereby provide a flow path in the manner of an inverted funnel for rising gases and entrained contaminants. 
     In preferred embodiments of the invention, the housing includes an upper panel, the end panels depending from the upper panel. A pair of grease filters is supported within an upper portion of the housing, the grease filters extending between the end panels and sloping downwardly and outwardly in opposite directions from a central portion of the housing. A pair of interior walls are supported within the housing in spaced relation to each other, each of the interior walls extending between the end panels below a respective one of the grease filters and sloping downwardly and outwardly in planes parallel to the planes of the respective grease filter. Thus, the grease filters and the interior walls define the cavity in an inverted V-shape in transverse section. An exhaust plenum is formed in the housing above the apex of the inverted V formed by the interior walls and the grease filters, the exhaust plenum being in fluid communication with the cavity by way of the grease filters. The exhaust outlet is formed in the upper panel of the housing and is in fluid communication with the exhaust plenum, whereby the exhaust plenum, together with the cavity and the exhaust outlet, provides the flow path in the manner of an inverted funnel for the rising gases and entrained contaminants. 
     The housing preferably includes a pair of side panels depending from the upper panel and extending between the end panels. 
     A grease drain system is also preferably provided, in which each of a pair of grease troughs, removably supported within the cavity, extends along a lower edge of a respective one of the grease filters. A removable grease cup is supported on one of the end panels, a first one of the grease troughs having an open end disposed above the grease cup, whereby grease draining from the respective grease filter is caught by the first grease trough and deposited in the cup by way of the open end of the first grease trough. A grease drain in the form of a channel is supported on the same end panel at an angle from the horizontal. The other grease trough also has an open end, the grease drain having an upper end disposed below the open end thereof, and a lower end disposed above the grease cup. Thus, grease draining from the second grease filter is caught by the other grease trough, directed to the grease drain by way of the open end of such other grease trough, and deposited in the grease cup by way of the lower end of the grease drain. 
     Also in preferred emodiments, each of a pair of grease catches extends between the end panels along a lower edge of a respective one of the interior walls. 
     The exhaust hood of the present invention provides a simple and more effective solution to the problem of providing adequate air exhaustion at a lower cost by providing an exhaust hood having an inverted V-shaped interior, wherein the walls comprising the inverted V include grease filters and the apex of the inverted V lies adjacent an exhaust duct in communication with an exhaust fan. Because the hood is thereby shaped like an inverted funnel, the naturally rising hot airflow must move toward the grease filters and exhaust duct. Thus, a relatively large negative pressure is not necessary to alter the airflow direction; instead, only negative pressure sufficient to draw the adjacent air through the duct is required. Consequently, a smaller exhaust fan and motor can be used. Also, a lower-powered HVAC system for exhausting air from the building may be employed. All these factors act in concert to lower building and utility costs. 
     Other features and advantages of the invention will be apparent from the ensuing description in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a perspective view of a prior art exhaust hood; 
     FIG. 2 is a sectional view of an exhaust hood according to the invention taken along line  2 — 2  of FIG. 3; 
     FIG. 3 is a perspective view of the exhaust hood of FIGS. 2 and 3; and 
     FIG. 4 is another perspective view of the exhaust hood of FIGS. 2 and 3, shown with a front panel removed. 
    
    
     DETAILED DESCRIPTION 
     Referring now to FIGS. 2 to  4 , an exhaust hood  10  is shown including a housing having front and rear end panels  12 ,  14 , an upper panel  16 , and side panels  18 ,  20 , which form a generally rectangular box-like structure defining an inverted V-shaped cavity  22  and having an open underside  24 . Interior walls  26 ,  28  slope upwardly from the underside  24  at the edges adjacent to the side panels  18 ,  20 , respectively, towards the center of the upper panel  16 . At their uppermost ends, the interior walls  26 ,  28  meet vertical upstanding walls  30 ,  32 , which connect the interior walls  26 ,  28  to the upper panel  16 . Preferably, the interior walls  26 ,  28  in the housing are comprised of stainless steel or aluminized steel. A pair of grease filters  34 ,  36  extend angularly upwardly from the interior walls  26 ,  28 , respectively, to a removable filter carrier  38 , which defines the apex of the inverted V-shaped cavity  22 . 
     An exhaust plenum  44  is defined by the grease filters  34 ,  36 ; the filter carrier  38 ; upstanding walls  30 ,  32 ; and the upper panel  16 . An exhaust duct  46  stands upwardly and outwardly from the exhaust plenum  44  through the upper panel  16 . Suction or negative pressure applied to the exhaust duct  46 , as by an exhaust fan (not shown) draws air from the exhaust plenum  44  out of the exhaust hood  10  through the exhaust duct  46 . 
     Typically, an exhaust hood such as the hood  10  will have several grease filters  34 ,  36  arranged in side-by-side arrangement to span the full length of the exhaust hood. The grease filters  34 ,  36  slope upwardly and forwardly at an angle of approximately 45°, in planes respectively parallel with the interior walls  26 ,  28 . The grease filters  34 ,  36  are mounted in the filter carrier  38  and a lower bracket  48 , which jointly retain the grease filters  34 ,  36 . The grease filters  34 ,  36 , include removable grease troughs  40  at a lower end adjacent the interior walls  26 ,  28 , and a handle  42  for aiding installation and removal. Preferably, the grease filters  34 ,  36  are ten-inch, UL listed baffle filters. The lower bracket  48  includes the removable grease trough  40 , which has a downwardly depending arm  64  mounting a U-shaped channel  66 , including an exterior face  68  extending at the same angle as the interior walls  26 ,  28 . 
     Below the removable grease troughs  40  extends a grease drain  90 , which is a channel angled downwardly and including an end disposed above a grease cup  92  removably supported by the rear panel  14 . Thus, as grease is removed by the filters  34 ,  36 , it drains from the filters to the removable grease troughs  40 , which channel the grease to the grease drain  90 , which lies below an end of the grease trough. In turn, the grease drain  90  channels the grease to the grease cup  92 , which can be emptied by simply removing it from the rear panel  14 . 
     The grease troughs  40  may preferably be open at each of their ends and the grease drain  90  and the removable grease cup  92  duplicated at the front end panel  12  in mirror image to facilitate the draining of grease from the filters  34 ,  36 . 
     Removable grease catches  94  line the bottom surfaces of the interior walls  26 ,  28  for accumulating the grease that will accumulate on the interior walls  26 ,  28  and flow or slide down the walls by force of gravity. The removable grease catches  94  store the accumulated grease until they are emptied by simply removing the grease catch from the lower edges of the interior walls  26 ,  28 . 
     The upper panel  16  includes hanging rods  80  for connecting the hood  10  to a support surface (not shown). Preferably, four hanging rods  80  are respectively disposed adjacent to the corners of the upper panel  16 . Of course, for a larger hood  10 , a greater number of hanging rods may be required. 
     In a typical commercial kitchen installation, the cooking equipment will be oriented beneath the exhaust hood  10 . The design described above is particularly adapted for an island-style preparation surface; that is, a preparation surface that is approachable from each end. Such an island-style preparation surface requires that the exhaust hood  40  be supported by the ceiling, via the hanging rods  80 , whereby the hood  10  is mounted above the preparation surface. After the kitchen equipment has been placed in the desired arrangement, the exhaust fan is operated so that smoke, fumes, and grease, such as from broilers and fryers, are exhausted from the room or other working space. The smoke, fumes, and grease are funneled inwardly towards the plenum  44  by the inwardly and upwardly extending interior walls  26 ,  28  toward the grease filters  34 ,  36 . 
     As described previously, grease drains from the filters to the grease troughs  40 , which channel grease to the drain  90 . The drain  90  channels the grease to the grease cup  92 , which can be removed to empty accumulated grease. The troughs  40 , drain  90  and cup  92  are removable to aid in cleaning the components. 
     While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.