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Publication numberUS3805685 A
Publication typeGrant
Publication dateApr 23, 1974
Filing dateJan 15, 1973
Priority dateJan 15, 1973
Publication numberUS 3805685 A, US 3805685A, US-A-3805685, US3805685 A, US3805685A
InventorsV Carns
Original AssigneeFischer Ind Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method and apparatus for cleaning grease filters in a ventilating system
US 3805685 A
Abstract
A grease extractor is mounted in a ventilation system for commercial cooking units. Control means are provided to alternately cycle spray nozzles located both above and below the filter to direct water and detergent mixed with water to the top and bottom of the filter in alternating sequences. Baffles are installed internal to the ventilating system to prevent the spray water from reaching the cooking unit and to direct the air flow through the filters. Troughs at the end of the baffles divert the spent water into a drain.
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United States Patent [1 1 [111 3,805,685 Carns 1 Apr. 23, 1974 [5 METHOD AND APPARATUS FOR 3,329,529 7/1967 Lamar 134 99 CLEANING GREASE FILTERS IN A 2,633,929 4/1953 Farr 55/242 X 3,055,285 9/1962 Gaylord 98/115 K VENTILATING SYSTEM 3,140,828 7/1964 Galanor 134/109 [75] Inventor: Vernon J. Carns, Modesto, Calif. 3,324,867 6/1967 Freese l34/99 z I 9 I l s I [73] Assignee glasfilflel Industries, nc Modesto Primary Exammer wmlam F. 013% Assistant Examiner-Paul Devinsky [22] Filed: Jan. 15, 1973 Attorney, Agent, or FirmWarren F. B. Lindsley [21] Appl. No.: 323,778

[57] ABSTRACT [52] U.S. Cl 98/115 K, 134/57 R, 134/95, A grease extractor is mounted in a ventilation system 134/29, 134/36, 134/199 for commercial cooking units. Control means are pro- 51 Int. Cl F23j 11/00, B08b 3/08 vided to alternately Cycle p y nozzles located both 53 Fie|d f Search 9 115 K, 115 55 22 above and below the filter to direct water and deter- 55/233 242 DIG 36; 137/ 24 13; 134/57 R gent mixed with water to the top and bottom of the 58 R, 99, 95, 199, 115 R, 171, 40, 36, 34, filter in alternating sequences. Baffles are installed in- 29 26 ternal to the ventilating system to prevent the spray water from reaching the cooking unit and to direct the 5 Ref Ci d air flow through the filters. Troughs at the end of the UNITED STATES PATENTS baffles divert the spent water into a drain.

3,242,652 3/1966 Malenchini 55/242 10 Claims, 7 Drawing Figures m m nAPR 23 1914 3.805685 SHEEI 1 BF 3 FIE-E17 Fi 20 36 METHOD AND APPARATUS FOR CLEANING GREASE FILTERS IN A VENTILATING SYSTEM BACKGROUND OF THE INVENTION This invention relates generally to a ventilating unit grease extractor adapted to extract grease and steamladen vapors from the vicinity of cooking ranges and the like, and more particularly to an improved method and apparatus for cleaning the grease extractor.

FIELD OF THE INVENTION In most large cooking units, especially those in restaurants and other commercial establishments, a forced air ventilating system with grease filters or extractors is used for the removal of the odors, vapors and heat created during cooking. Such vapors are normally laden with vaporized fat, greases and oils liberated during the cooking processes. The grease filters along with baffles PRIOR ART The removal of the grease filters for the cleaning process is a dirty, messy job and frequently is postponed as long as possible. If the filters are not cleaned, the can become clogged with the grease and dirt trapped by the filter. Thus the filter itself, if it is not removed and cleaned often, frequently becomes a fire hazard.

Cleaning apparatus such as a spray nozzle mounted above the filter was provided to accomplish the cleaning of the filter while installed in the ventilating system. Baffles and a drain were provided to prevent the cleaning spray mixture from contacting the cooking unit and to drain off the dirty water after the cleaning process. However, most of the dirt is embedded in the grease laden filters from beneath the filter and is for the most part untouched by the spray nozzle directed at the filter from above. Also, for best cleaning results an agitated action is necessary. Thus what is needed is a method and apparatus for thoroughly cleaning the grease filter of a ventilating system of a cooking unit.

SUMMARY OF THE INVENTION The ventilating system for a cooking unit according to the present invention comprises separate ventilating sections mounted over the cooking unit and connected to a common air chamber which is in turn connected to a plenum and flue exhausting to a chimney. An exhaust fan or blower induces an air flow from above the cooking unit into each ventilating section, the air chamber and into the flue and chimney. Each ventilating section includes a grease filter or extractor mounted in the air flow, an upper and lower liquid spraying means such as nozzles directly to the top and bottom respectively of the grease filter, baffles mounted in the air chamber to direct the air flow and to prevent the liquid from the spray nozzles from reaching the cooking unit, troughs to divert the sprayed liquid into a drain, and associated plumbing to carry cleaning liquid to the upper and lower spray nozzles. Associated plumbing and control means are provided to alternately cycle the liquid through the upper and lower spray nozzles. Temperature sensitive means may be located in each air chamber to actuate one or both spray nozzles and turn on the exhaust ventilating system and shut off the system supplying air to the kitchen in the event of a fire.

The method of cleaning the grease filters comprises the steps of prewashing the grease filters by alternately spraying liquid at the grease filter under a high pressure through the upper spray nozzle and then the lower spray nozzle, warming the filters with hot liquid to approximately the temperature of the liquid .by alternately cycling the upper and lower spray nozzles, adding degreasing chemicals to the hot liquid for spraying the grease filter via the upper spray nozzles, shutting off the liquid and the degreasing chemicals to the spray nozzles, allowing the liquid water mixture to soak into the grease filter, and finally rinsing the grease filter by alternately cycling hot liquid to the upper and lower grease nozzles at a high pressure to clean off any grease from the filters by alternately spraying the liquid onto the grease filter from above and below the filter.

It is, therefore, an object of the present invention to provide an enhanced ventilating system for use in cooperation with commercial cooking units.

It is another object of the present invention to provide a ventilating system having an enhanced apparatus for cleaning a grease filter in a ventilating system without removing the grease filter from the ventilating unit.

It is yet another object to provide apparatus for cleaning grease filters in a ventilating system by alternately applying a cleaning fluid to the grease filter from 'above and below the grease filter.

BRIEF DESCRIPTION OF THE DRAWING The various novel features of this invention, along with the foregoing and other objects, as well as the invention itself both as to its organization and method of operation, may be more fully understood from the following description of an illustrated embodiment when read in conjunction with the accompanying drawing, wherein:

FIG. 1 is a perspective view of a typical commercial cooking unit provided with a ventilating system including improved grease filters according to the present invention;

FIG. 2 is a vertical cross section of a ventilating section taken along line 2-2 of FIG. 1 showing the grease filter and associated apparatus according to the present invention which may be used above deep-fat frying units;

FIG. 3 is a vertical cross section of a ventilating section taken along line 3-3 of FIG. 1 showing the grease filter and associated apparatus for use above surface cooking units;

FIG. 4 is a vertical cross section of a ventilating section taken along line 4-4 of FIG. 1 showing the grease filter and associated apparatus according to the present invention for use above a broiler and/or oven unit;

FIG. 5 is a cross-sectional view of a ventilating system showing a second embodiment of the present invention;

FIG. 6 is a diagrammatic view of the interconnect liquid control supply for use with the ventilating system of FIG. 1; and

FIG. 7 is a simplified schematic of a control unit for cycling the apparatus according to the present inven-' tion through a washing cycle of the grease filter.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, FIG. 1 illustrates a typical commercial cooking unit l0vcomprising two deep-fat frying units 12, a grill unit 14, a two-range unit 16, and a broiler unit 18, together with appropriate ovens associated with the broiler unit 18. The selection and the arrangement of the particular units is generally a matter of choice and can be varied at will without affecting the operation of the present invention. The placement of the units such as the two deep-fat frying units 12 and the grill and surface units are to provide an arrangement dictated by the use of the unit and the particular type of hood associated with that commercial cooking unit.

The cooking unit 10, as shown in FIG. 1, is provided with a ventilating system 22 having a plurality of ventilating sections 24, 26 and 28. The first ventilating section 24 uses a low profile hood or canopy 30 which overhangs the deep-fat frying units 12. A cross section of the ventilating section used over the deep-fat frying units 12 is shown in FIG. 2. A shallower hood 32 and different baffles comprise the second ventilating section usedover the surface and grill units 16 and 14. The hood 32 over these units is also a low profile hood and a cross section of the ventilating section 26 for the surface cooking unit 16 and grill unit 14 is shown in FIG. 3. .The third ventilating section 28, the oven or broiler ventilating section, is a high'profile system adapted to be arranged above higher level units such as the broiler unit 18 and oven units 20 stacked as shown in FIG. 1. The air input 34 and baffle arrangement in the oven ventilating section 28 for the broiler and oven units is shown in FIG. 4. The height of each of the ventilating sections is such that the separate entrance ways are as close as possible to the surface of the cooking unit while at the same time allowing sufficient clearance for the necessary operation of the cooking unit.

Referring again to FIG. 1, all three ventilating sections 24, 26 and 28 are connected to a common air type driven by an electrical motor can be used as the exhaust fan in the present embodiment. I

The function of the ventilating system 22 is to collect the fumes, smoke and grease-laden vapors coming from I the cooking unit 10 and to exhaust the smoke and fumes to the atmosphere. This is accomplished as mentioned above by maintaining a constant flow of air from the kitchen across the cooking unit 10 and out through the ventilating sections 24, 26 snd 28, the plenum 38 and the flue. The three ventilating sections are adapted to rest on and be supported by the separate cooking units by means of brackets as shown in FIG. 1, and to fit closely around the sides and back of the cooking unit to direct the air flow from across the cooking units 10 into the ventilating system 22. Optionally, the back of the ventilating system 22 can include a separate duct work 40 opening into the common air chamber 36 from the rear of the cooking units. This duct work 40 can be used to direct flue gases from the cooking units into the ventilating system 22 and out into the atmosphere. An adjustable draft regulator (not shown) can be provided in each section to adjust the air flow through each ventilating section.

In order to show the apparatus according to the present invention, reference is made to the cross-sectional views illustrating the air flow through the different sections as shown inFIGS. 2, 3 and 4 taken together with FIG. 1.

Referring to FIGS. land 2, the deep-fat frying ventilating section 24 comprises the elongated hood 30 extending over the deep-fat frying units 12. The hot vapors from the deep-fat frying units 12 are drawn into an entrance way 42 at the rear of the hood 30 from the negative pressure created by the exhaust fan. The hot vapors are deflected rearwardly and downwardly by an entrance baffle 44 over an upwardly and forwardly extending bottom baffle 46. Theentrance baffle 44 froms an integral part of the rear of the hood 30 and inclines the hot vapors downwardly toward the bottom baffle 46 and backward toward a rear wall 48. Internal to the I ventilating section is an upper spray forming means and chamber 36 (internal to the units, see FIGS. 2, 3 and 4) which in turn is'connected 'to a plenum 38. The plenum may-be connected by normalduct work either directly to the atmosphere outside of the kitchen or can be connected to a chimney or a flue in a conventional manner. An exhaust fan or blower (not shown) is provided in the plenum at some convenient location for the purpose of inducing an air flow from the area above the cooking surface through the ventilating sections 24, 26 and 28, the common air chamber 36 and the plenum 38 out into the atmosphere. It is obvious that any type of fan such as the commonly known squirrel cage a lower spray forming means such as the upper spray nozzle 50 and the lower spray nozzle 52. Both spray nozzles 50 and 52 are directed toward a grease filter 54 mounted in the airstream. The entrance baffle 44 is formed at its lower section to operate as a lip to direct the liquid forced from the spray nozzles behind the bottom baffle 46 and on into a trough 56 and drain pipe 58 combination. The grease is removed from the vapors by the grease filter 54 and the remaining air passes into the plenum 38 above the filter 54 via the common air chamber 36. r

The ventilating system according to the present invention is designed to wash either grease filters or grease extractors in their normal position in the ventilator section. The spray nozzles are located both above and below the grease filter and spray the cleaning liquid such as water and detergent on the filter alternately from both top and bottom. The liquid draining from the grease filters is collected in a trough with a drain pipe taking the spent liquid to a sewer. The function of a grease filter is to provide ample surface area to cool the vapors from the cooking units sufficiently for the grease to be condensed and deposited on the filter media. The efficiency is directly related to the clean surface area contacted by the grease-laden vapors. The grease filter may be constructed of several sandwiched layers of deep corrugated steel mesh between two expanded metal faces, held together by a steel channel frame. Drain holes are provided in the frame. The steel mesh may be constructed of galvanized or stainless steel to prevent rust. It is the very efficiency of the steel mesh which causes the problems of prior art cleaning units. The pulsating, alternating spray from both sides of the filter according to the present invention permits a thorough cleaning through the multiple meshes of the filter.

Grease extractors may be used in the ventilating sections in place of grease filters. The grease extractors are generally centrifugal extractors which pass the greaseladen vapors through tortuous passages at high velocities to sling off the grease from the extractor by centrifugal force. Most of the grease drains into the trough, but some remains in the extractor. The extractors must also be cleaned periodically to maintain their efficiency.

Still referring to FIGS. 1 and 2, the hood 30 and the entrance way 42 extend along the length of the ventilating section 24 and thus extend along the width of the two deep-fat frying units 12. Likewise the entrance baffle 44, the bottom baffle 46, the rear wall 48, and the grease filter 54 extend across the width of the deep-fat frying ventilating section 24. The trough 56 formed at the bottom of the ventilating section 24 can be downwardly sloped from one end to the other with the drain at the low section or can be downwardly sloped from both ends toward a centrally placed drain. The trough 56 extends basically beneath the filter 54 and baffles 44 and 46 to catch the water sprayed onto the filter 54 and any excess grease dripping from the filter 54. The drain pipe 58 extends from the bottom of the trough 56 and when the cleaning apparatus is in use, this drain pipe is connected to a suitable sewer connection.

The grease filter 54 is mounted at an angle sloping downwardly toward the front of the ventilating section 24 in order to provide a larger surface area to the vapors passing through the filter and also to provide an angle for the cleaning fluids ejected by the spray nozzles 50 and 52 to drip by gravity from the back and raised portion of the filter 54 to the front lowered portion, through the drain holes in the filter 54, along the inward portion of the entrance baffle 44, down across the lip of the entrance baffle 44 onto the internal portion of the bottom baffle 46 and into the trough 56 and drain pipe 58. The entrance baffle 44 and the bottom baffle 46 are preferably fastened by clips or screws (not shown) for easy removal. Likewise the grease filter 54 is pressure-fit into place for easy removal.

The ventilating section 26 over the surface unit section as shown in FIG. 3 is similar in construction to the deepfat frying ventilating section 24 just described in FIG. 2. Because of the shorter hood 32 required above the surface unit to provide for working area for the cook, the ventilating section 26 shown in FIG. 3 requires that the grease filter be placed at a more severe angle. Referring to FIGS. 1 and 3, the hot grease-laden vapors are gathered by the hood 32, directed through an entrance way 60 via an entrance baffle 62. The entrance baffle 62, as shown by the arrows showing the air flow. is directed downwardly and rearwardly toward a bottom baffle 64 and a rear wall 66. The hot vapors are drawn through another grease filter 65 or extractor located in the surface unit ventilating section 24 into the common air chamber 36 and out into the plenum 38. This ventilating section 24 also includes a lower spraying apparatus and an upper spraying apparatus shown as a lower spray nozzle 68 directing a liquid spray to the underside of the grease filter 65 and an upper spray nozzle 70 directing a liquid spray to the top section of the grease filter 65. This ventilating section 24 is similarly formed such that the liquid sprayed onto the filter 65 by the upper and lower spray nozzles 68 and 70 is directed via the interior portion of the entrance baffle 62 along a lip of the entrance baffle 62 down into a trough section 72 and from the trough section 72 into a drain pipe 74. Again in this section, the entrance baffle 62 and bottom baffles 64 are fastened by screws or clips for easy removal along with the grease filter 65.

A third ventilating section, the broiler and oven ventilating section 28, is shown in cross-sectional view in FIG. 4. Referring to FIGS. 1 and 4, the grill and oven ventilating section 28 comprises similar apparatus as that shown and described in FIGS. 2 and 3 for the deepfat frying and surface units. The grill and oven ventilating section 28, however, is a high-level unit and thus the grease filter is located in a different plane. ln FIG. 4 the hot vapors from the grill and oven cooking units 18 and 20 are directed via the air input 34 directly into the ventilating section 28 without an extending hood. The air input 34 is formed from sheet metal formed inwardly and downwardly from the top of the ventilating section 28. A lower lip of the air input 34 is formed from sheet metal from the lower section of the ventilating system. The lower lip is formed upwardly and outwardly from the bottom portion of the ventilating section 28. Thus the entrance way 34 into the ventilating section 28 is at a sloping angle as shown in FIG. 4. A decorative screen can be used to cover the entrance way 34.

The broiler and oven ventilating section 28 is formed as a unit supported directly by the broiler and oven unit. The ovenventilating section 28 is thus formed with a bottom section 78 for resting on the top of the grill and oven units and an internally placed sheet metal baffle 80 forming the internal air chamber 36. The hot vapors drawn from the front opening of the broiler and oven units are directed into the entrance way 34 across the entrance baffle 82 formed to reduce the cross section of the exhaust stream to increase the air velocity. Fumes, which may contain grease, rising from the broiler or oven flues are diverted and directed by baffle 80 to the area between entrance way 34 and entrance baffle 82 at which place they are aspirated or induced into the exhaust stream entering grease filter 84. Grease filter 84 is supported by brackets 86 for ease of removal in an upward and backward direction in the ventilating section 28. The grease vapors are removed by the grease filter 84 and the remaining air is drawn into the common air chamber 36 shared with the other ventilating sections. In this ventilating section 28, an upper spraying device shown as a spray nozzle 88 directs a liquid spray to the upward facing portion of the filter 84 which in FIG. 4 is the section of the filter that meets the grease laden vapor in the first incident. A lower spraying device, such as a lower spray nozzle 90, is directed toward the under-portion of the grease filter 84 which in this ventilating system is the rearward or clean air section of the grease filter. The liquid sprayed by the spray nozzles 88 and 90 is collected on the entrance bafile 82. The entrance baffle 82 slopes slightly downward as the entrance baffle 82 extends toward the rear of the ventilating section. The downward slope takes the spent cleaning liquid into a trough 92 at the rear of the ventilating section out into a drain pipe 94. The entrance baffle 82 prevents the spray from the nozzles 88 and 90 from escaping past the entrance way 34 out into the broiler and oven units during a cleaning cycle.

The upper and lower spray nozzles of each ventilating section is controlled by a separate pair of remote control valves such as solenoid valves interconnected with a main hot water valve and a detergent tank. Referring to FIG. 6, a schematic outline of the plumbing interconnections isshown. A hot water input directs a cleaning liquid such as water via pipes 95 to a remote control valve Vrn controlling the path of the water through a separate path or trough a venturi valve 96 for siphoning a degreasing chemical such as detergent from a detergent tank 98. The water pipes 95 are directed to the three ventilating sections, schematically shown as blocks 24, 26 and 28. The water pipes 95 in each section are directed to an upper and lower remote control valve, schematically shown as VlB and VlT controlling the lower spray nozzles 52 and upper spray nozzle 50, respectively, of the deep-fat frying ventilating section 24, V2B and V2T controlling the lower spray nozzle 68 and upper spray nozzle 70, respectively, of the surfaceventilation section 26, and V3B and V3T controlling the lower spray nozzle 90 and upper spray nozzle 88, respectively, of the oven and grill ventilating section 28.

The normal wash is as follows: first, the pre-rinse hot water cycle is turned on, spraying water at a low pressure through the filters in the section to be washed in an alternating manner, actuating first the top spray nozzle and then the bottom spray nozzle and repeating until the filter is warmed by the hot water. After the pre-rinse cycle, a wash cycle is performed. The detergent is siphoned into the water lines by closing valve Vm, thereby forcing the water flow through the venturi. The venturi will siphon detergent from the detergent tank and add the detergent to the hot water. It should be recognized that an electric pump may be used in place of or in addition to the venturi. The mixture of water and detergent is directed to the same spray nozzles and the mixture is again alternately sprayed on the filters from above and below by alternately actuating the solenoid valves. After the wash cycle, a soak cycle permits the detergent and water mixture to soak in the filter from above and below to loosen any grease within the filter. After the soak cycle, a high pressure hot water rinse is alternately directed to the same upper and lower spray nozzles to blast off any grease with the alternating, pulsating water spray. After this 'cycle. the next ventilating section is cycled through the same wash cycle. A circuit control means which may be used, for example, to control a wash cycle is shown in FIG. 7.

Referring to FIG. 7, the ventilation and washing of the grease filter cycles can be controlled manually by push buttons or automatically by time switches. Depression of a FAN button 100 starts the ventilating cycle by applying electrical power to the exhaust fan 101. The FAN light 102 will be illuminated when the power is applied to the fan motor. Depressing the FAN button 100 activates relay R1, which through its contacts both applies power to the exhaust fan 101 and provides a holding .circuit through normally closed contacts of both relays R2 and R3. In all relays, C represents the common or switching contact, NC represents the contact normally completed if the relay is not activated, and NO represents the contact completed with the C contact when the relay is activated.

Depressing the OFF button 104 opens all holding circuits which de-energizes all relays, thereby stopping all power to all the devices.

A WASH button 106 is provided to manually start the wash cycles. During the wash cycle the WASH light 108 is illuminated. Depressing the WASH button energizes relay R2. Energizing relay R2 stops the exhaust fan 101 and energizes a timer 112 and contacts T1 for the PRE-RINSE cycle. Solenoid valves Vm and VlB are opened. Alternating relay 110 is activated. Alternating relay 1 10 is an alternating means which activates and deactivates in a regular timed cycle to alternate the activation of solenoid valves VlT and VlB. Valves VlB and VlT alternately activate the lower and upper valves 50 and 52 of ventilating section 24 (see H0. 6).

At the end of the PRE-RINSE cycle, timer 112 contacts T1 deactivates energizing contactsTZ for the WASH cycle. Valve Vm is closed, forcing the water to flow through the venturi valve which siphons detergent into the system. The higher pressure drop through the venturi leaves a lower pressure for the spray nozzles and consequently a soft spray is applied to the grease filters during a WASH cycle. The alternating relay 110 again alternately activates the valves controlling the upper and lower spray nozzles to cause the detergent and water mixture to be applied in alternating cycles to both sides of the filter.

It should also be recognized that it is intended to disclose and cover in this application the spraying of water and detergent mix on the top of the filters only and let this mixture soak in, thereby saving detergent over alternating cycle usage.

At the end of the WASH cycle, contacts T3 of the timer 112 are energized for the SOAK cycle. Valve Vm is opened but both valves V18 and V1T are closed, turning off the spray nozzles. The SOAK cycles allow the detergent and water mixture to soak into the filters and loosen any accumulated grease in the filters.

When the SOAK cycle is completed, timer contacts T4 are energized for the FINAL RINSE cycle. Valve VIB and VlT are alternately opened via the alternating relay 110. The high pressure hot water is pulsed, alternately through the upper and lower spray nozzles to the filter. After the FINAL RINSE cycle, assuming a multisection system, valves Vm, V113 and VlT are closed and the timer 112 is set to home. A step switch 114 is energized to advance to the next position to permit control of the V28 and V2T valves in the ventilating section 26. The system automatically repeats the above cycle for the next section. Similarly, all of the ventilation sections are washed in turn via the step switch 114 until all of the ventilation sections are cleaned.

At the conclusion of the FINAL RINSE cycle for the last section, relay R3 is tie-energized, stopping the cleaning cycle, resetting the step switch 114, resetting the timer 112 and closing all valves.

The control cycle for the wash cycle may be auto matic. A time switch- 116 can be used to automatically start the wash or cleaning cycle during the time that the establishment is closed. No one need be around to start the cycle.

Float switch 118 measures the level of the liquid detergent in the detergent tank. If the level of detergent gets low, an indicating light 120, marked LOW, is illuminated to notify an attendant that the detergent supply needs replenishing.

Fire protection is automatically provided by thermostats F1, F2 and F3 measuring the temperature of the gases rising from the cooking equipment. In case of abnormal temperature, the thermostats activate the exhaust blower (see FIG. 7) to draw the fire and smoke into the ventilating system and also activate the water valves to spray water or fire preventative liquid through all of the upper and/or lower spray nozzles to prevent the flames from penetrating the grease filter. The exhaust blower creates a negative pressure in the kitchen to help prevent the fire and smoke from spreading to other areas. The system may be arranged to shut off the fuel to the cooking unit in the event of a fire by connecting the thermostats to a gas valve or electric power switch, thereby removing the fuel and heat supporting the fire. The circuit for controlling a fuel cut-off valve 122 is shown in FIG. 7. Whenever the temperature of the gases in any unit rises above the ratings of the thermostats F1, F2 and F3, relay R4 is activated, opening all valves Vm, VlB, VlT and such, turning on the exhaust fan 101 and closing the fuel cut-off valve 122.

Although the preferred embodiment discloses a ventilating system designed to be mounted on the cooking units, it is obvious that the ventilating section of the system could be designed for wall mounting or suspended over the cooking units without departing from within the scope of this invention. For instance, a ceiling suspended ventilating system for use over cooking units placed in the center of a room is shown in FIG. 5. in FIG. 5, two filter island type ventilating system 124 is shown. The island type ventilating system 124 comprises a hood 126 supported from the ceiling by adjustable hangers 128. An air passage 130 is provided to draw the hot grease-laden vapors past entrancebaffles 132, bottom baffles 134 and through two grease filters 136 mounted with the. tops of the grease filters 136 touching a common bracket 138 and with the bottom of each grease filter 136 supported by the entrance baffles 132. One lower nozzle 140 with a double head applies the spray liquid to the bottom of the filters 136. Two upper nozzles 142, one for each filter, apply the spray liquid to the top of the filter. The cleaned air passes into a plenum 144 or flue chamber after the filters 136. An exhaust fan (not shown) provides the negative air pressure to draw the air from around the cooking units used under the island type hood 126. The water from the filter is gathered by the bottom baffles 134, directed to a trough 146 and a drain pipe 148. In this type of application, the alternating cycle of the nozzles can activate both top nozzles 142 together and then the bottom nozzle 140.

Further, a control system is shown for cycling the wash cycle to operate on each ventilating section in turn. It is obvious that all ventilating sections can be washed at one time by having one valve controlling all lower spray nozzles and another controlling all upper spray nozzles. The same alternating, pulsating wash cycle can be used, washing all of the filters in the ventilating system at one time.

it is further obvious that other types of control systems could be used without departing from the present invention. For instance, the timing control and alternating relay could be obtained by using a standard washing machine timer with a rinse alternating cycle. The timing of some cams activating the switches in a usual washing machine might have to be changed but the intent is obvious.

The appended claims are, therefore, intended to cover and embrace any such modifications, within the limits only of the true spirit and scope of the invention.

What is claimed is:

1. A ventilating system arranged above a cooking unit in close proximity thereto to remove vapors and gases emanating therefrom, said ventilating system comprising:

a hood means placed above the cooking units for capturing the vapors and gases from the cooking units;

an air chamber connected to said hood means;

a plenum connecting said air chamber to the atmosphere;

a grease removing means placed in said air chamber for removing grease from the vapors and gases emanating from the cooking units, said grease removing meansbeing oriented in said air chamber to incline upward at an angle to the horizontal;

exhaust means associated with said plenum for inducing a current of air to draw the vapor and gases captured by said hook means through said grease removing means, said air chamber, and said plenum into the atmosphere;

an upper spray forming means mounted above said grease removing means for spraying a liquid against a top side of said grease removing means;

a lower spray forming means mounted below said grease removing means for spraying a liquid against a bottom side of said grease removing means;

control means for activating the upper and lower spray forming means for permitting the liquid to be sprayed by the upper spray forming means and the lower spray forming means onto the grease removing means;

a plurality of removable baffles fastened in said air chamber to direct the induced current of air through said grease removing means and to prevent the sprayed liquid from reaching the cooking units;

a trough formed in said air chamber to capture the spent sprayed liquid; and

a drain pipe connected to said trough for directing the sprayed liquid to a drain,

said control means includes remote control means and alternating means to alternately activate the upper and lower spray forming means for permitting the liquid to be alternately sprayed by the upper spray forming means and the lower spray forming means.

2. A ventilating system as defined in claim 1 wherein the grease removing means is a noncorrosive steel grease filter comprising a plurality of sandwiched layers of deep-corrugated metal mesh, a pair of expanded metal faces, and a channel frame holding the mesh layers between the metal faces, said channel frame including a plurality of drain holes formed in at least one end of the channel frame.

3. A ventilating system as defined in claim 1 wherein the grease removing means is a noncorrosive steel, centrifugal grease extractor.

4. A ventilating system as defined in claim 1 wherein said upper and lower spray forming means each include a spray nozzle directed toward said grease removing means.

5. A ventilating system as defined in claim 1 wherein said remote control means of said control means in cludes solenoid operated valves alternately activated by said alternating means and alternately controlling the liquid directed to said upper spray forming means and said lower spray forming means.

6. A ventilating system as defined in claim 5 wherein the liquid sprayed from said upper and lower spray forming means is water and a degreasing chemical such as detergent mixed with water and wherein the ventilating system further includes means activated by said control means for introducing the detergent to the water.

7. A ventilating system as defined in claim 6 further including timing means for controlling the operation of the solenoid operated valves, the means for introducing the detergent to the water, and the alternating means, to cycle the operation of each to allow water only and the water and detergent mixture to be alternately and cyclically directed to both sides of the grease removing means to clean the grease from the grease removing means.

8. A ventilating system as described in claim 1 further including thermostats for controlling said control means to activate said exhaust fan and said upper and lower spray forming means to spray the grease removing means in the event of a fire in the ventilating system, and further including a means for interrupting the fuel flow to the cooking unit activated by said thermostat.

9. A ventilating system arranged above a cooking unit in close proximity thereto to remove vapor and gases emanating therefrom, said ventilating system comprising:

a hood placed above the cooking units capturing the vapors and gases from the cooking units;

an air chamber connected to said hood;

a plenum connecting said air chamber to the atmosphere;

a plurality of removable baffles fastened in said air chambers;

a grease filter removably fastened to said plurality of removable baffles and oriented in said air cham-- bers to incline upward at an angle to the horizontal;

an exhaust fan mounted in' said plenum and inducing a current of air to draw the vapor and gases captured by said hood through said grease filter, said air chamber, and said plenum into the atmosphere;

an upper spray nozzle mounted in said air chamber and directed to spray a liquid at the top side of said grease filter; I a lower spray nozzle mounted in said air chamber and directed to spray a liquid at the bottom side of said grease filter; plumbing means for connecting said upper and lower spray nozzles to a source of a liquid such as hot water; a tank containing detergent; valve means for introducing the detergent to the hot water via the plumbing means; solenoid operated valves connected to said plumbing means and controlling the flow of the hot water and the hot water and detergent mixture so said upper and lower spray nozzles; alternating means connected to said solenoid operated valves for alternately operating said solenoid operated valves; control means for activating said alternating means, said valve means and said exhaust fan to operate the ventilating system and to cycle said alternating means and 'said valve means to clean said grease fil ter; a trough formed in said air chamber to capture the spent water; and a drain pipe-connected to said trough for directing the spent water to a drain; a plurality of removable baffles formed to prevent the sprayed liquid from reaching the cooking units. 10. A process for cleaning grease from a grease filter mounted in a ventilating system at an inclined angle to the horizontal, the ventilating system being arranged above a cooking unit in close proximity thereto and ineluding means for inducing a current of air to carry grease-laden vapors from above the cooking units through the grease filter, said process comprising:

prewashing the grease filter by alternately spraying at a high pressure, a hot liquid at the top side of the filter and then the bottom side of the filter, and then repeating until the grease filter is warmed to the temperature of the hot liquid; adding a degreasing chemical to the hot liquid; washing the grease filters by alternately spraying at a lower pressure, the mixture of the degreasing chemical and the hot liquid at the top side of the filter and then the bottom side of the filter, and then repeating until the grease filter is saturated by the mixture; allowing the mixture to soak into the grease filter and soften the grease from the grease filter; and ringing the grease filter by alternately spraying at a high pressure, the hot liquid at the top side of the filter and then the bottom side of the filter, and then repeating, thereby pulsing the hot liquid at the filter until the mixture and the grease is removed from the filter.

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4066064 *Apr 8, 1976Jan 3, 1978Mcgraw-Edison CompanyKitchen ventilator damper actuator and control
US4066425 *Aug 30, 1976Jan 3, 1978Nett Louis AVentilating apparatus including exhaust filter exchanger
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Classifications
U.S. Classification126/299.00E, 134/104.1, 134/95.3, 134/29, 55/DIG.360, 134/57.00R, 134/36, 96/228, 134/199
International ClassificationF24C15/20
Cooperative ClassificationF24C15/20, Y10S55/36
European ClassificationF24C15/20