U.S. patent number 3,785,124 [Application Number 05/168,019] was granted by the patent office on 1974-01-15 for pollution-free kitchen ventilator.
This patent grant is currently assigned to Gaylord Industries. Invention is credited to Asa K. Gaylord.
United States Patent |
3,785,124 |
Gaylord |
January 15, 1974 |
POLLUTION-FREE KITCHEN VENTILATOR
Abstract
A ventilating hood has an ascending exhaust duct equipped with a
series of air cleaning and purifying instrumentalities for removing
grease, smoke and fumes generated by cooking equipment. Air rising
through the duct passes successively through a grease extractor, an
electrostatic precipitator, an activated charcoal filter and a
deodorizing chemical spray. The grease extractor and precipitator
are provided with hot water and detergent washing sprays. The hood
has hollow walls containing air supply conduits for fresh air
outlets which discharge streams of fresh air for sweeping into the
exhaust duct smokey and grease-laden air from the cooking
equipment. A control system provides an automatic wash and dry
cycle for the grease extractor and precipitator and includes
thermostatic control means for closing fire dampers and turning on
the water sprays in case of fire in the ventilator.
Inventors: |
Gaylord; Asa K. (Portland,
OR) |
Assignee: |
Gaylord Industries (Lake
Oswego, OR)
|
Family
ID: |
22609744 |
Appl.
No.: |
05/168,019 |
Filed: |
August 2, 1971 |
Current U.S.
Class: |
96/19; 126/299D;
96/31; 96/53; 96/55; 96/407; 55/DIG.36; 126/299E |
Current CPC
Class: |
F24C
15/2057 (20130101); B03C 3/08 (20130101); B03C
3/47 (20130101); B03C 3/78 (20130101); B03C
3/017 (20130101); Y10S 55/36 (20130101) |
Current International
Class: |
F24C
15/20 (20060101); B01d 050/00 () |
Field of
Search: |
;55/124,118,242,126,120,139,122,217,220,316,279,DIG.36
;98/115K |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Super Compact Line Electronic Air Cleaner Models 908 to 932 Manual
SC900 - C Emerson Electric dtd 11/24/69 pages 1-10.
|
Primary Examiner: Nozick; Bernard
Attorney, Agent or Firm: Schermerhorn; Lee R.
Claims
Having now described my invention and in what manner the same may
be used, what I claim as new and desire to protect by Letters
Patent is:
1. Ventilating apparatus for kitchen cooking equipment comprising a
hood adapted for mounting above said cooking equipment, said hood
having a hollow back wall, a pair of hollow end walls and a hollow
top wall, an exhaust duct in an upper portion of said back wall
having an inlet opening under said top wall for smoke and
grease-laden air from said cooking equipment, a grease extractor in
said exhaust duct in said hollow back wall, an upper air outlet
opening extending along the under side of said top wall at the
front edge thereof, a pair of end air outlet openings extending
along front edge portions of said end walls, an air supply duct in
said top wall for said upper outlet opening, and air supply ducts
in said end walls for said end outlet openings, said ducts in said
end walls being connected with said duct in said top wall.
2. Apparatus as defined in claim 1 including an electrostatic
precipitator in said exhaust duct downstream from said grease
extractor.
3. Apparatus as defined in claim 2 including an activated charcoal
filter in said exhaust duct downstream from said precipitator.
4. Apparatus as defined in claim 3 including deodorizing chemical
spray means in said exhaust duct downstream from said charcoal
filter.
5. Apparatus as defined in claim 4 including washing spray means
for said grease extractor and precipitator.
6. Apparatus as defined in claim 5, said exhaust duct extending
upward from said inlet opening with said grease extractor,
precipitator, charcoal filter and deodorizing spray being disposed
one above the other so that wash liquid from said precipitator
drains through said grease extractor, and said charcoal filter and
deodorizing spray are above said washing sprays.
7. Ventilating apparatus for kitchen cooking equipment comprising a
hood adapted for mounting above said cooking equipment, an
ascending exhaust duct having an inlet opening in said hood for
smoke and grease-laden air from said cooking equipment, a grease
and liquid collecting trough having a drain in the lower end of
said duct, a grease extractor in said duct above said inlet
opening, an electrostatic precipitator in said duct above said
grease extractor, washing spray nozzles in said duct arranged to
wash said grease extractor, washing spray nozzles in said duct
directed upward toward the under side of said precipitator, and
washing spray nozzles in said duct directed downward toward the
upper side of said precipitator, the washing liquid from said
precipitator draining through said grease extractor to said
trough.
8. Apparatus as defined in claim 7 including a charcoal filter in
said duct above said precipitator, and a deodorizing chemical spray
in said duct above said filter.
9. Ventilating apparatus for kitchen cooking equipment comprising a
hood adapted for mounting above said cooking equipment, an exhaust
duct in said hood having an inlet opening for smoke and
grease-laden air from said cooking equipment, an air supply duct in
said hood having an outlet opening in spaced relation to said inlet
opening, a grease extractor in said exhaust duct, an electrostatic
precipitator in said exhaust duct downstream from said grease
extractor, an activated charcoal filter in said exhaust duct
downstream from said precipitator, deodorizing chemical spray means
in said exhaust duct downstream from said charcoal filter, and
washing spray means for said grease extractor and precipitator.
10. Apparatus as defined in claim 9 including a control system
having a start switch arranged to start fans in said exhaust and
air supply ducts, energize said precipitator and start said
chemical spray means; a timing device; a stop switch arranged to
stop said fans and said chemical spray means, deenergize said
precipitator and start said timing device; said timing device then
starting said washing spray means for a washing period, stopping
said washing spray means after said washing period and starting
said fans for a drying period, and then stopping said fans.
11. Apparatus as defined in claim 10 including a thermostatic
switch in said exhaust duct and fire dampers in said exhaust and
air supply ducts, and means in said system actuated by said
thermostatic switch in case of fire in said exhaust duct to stop
said fans, close said dampers, and operate said washing sprays for
fire extinguishing purposes.
12. Ventilating apparatus for kitchen cooking equipment comprising
an exhaust duct for smoke and grease-laden air from said cooking
equipment; an exhaust fan; a grease extractor and electrostatic
precipitator in said duct; washing spray means for said grease
extractor and precipitator; a control system; a start switch in
said control system arranged to start said fan and energize said
precipitator; a timing device in said system; and a stop switch
arranged to stop said fan, deenergize said precipitator and start
said timing device; said timing device then starting said washing
spray means for a washing period, stopping said washing spray means
after said washing period and starting said fan for a drying
period, and then stopping said fan.
13. Apparatus as defined in claim 12 including a thermostatic
switch and fire damper in said duct, and means in said system
actuated by said thermostatic switch in case of fire in the duct to
stop said fan, close said damper and operate said washing sprays
for fire extinguishing purposes.
14. Ventilating apparatus for kitchen cooking equipment comprising
a hood adapted for mounting above said cooking equipment, an
ascending exhaust duct having an inlet opening in said hood for
smoke and grease-laden air from said cooking equipment, a grease
and liquid collecting trough in the lower end of said duct and
having a drain, a grease extractor in said duct above said inlet
opening and trough, washing spray means in said grease extractor
arranged to wash said grease extractor, an electrostatic
precipitator in said duct above said grease extractor, washing
spray means in said duct adjacent said precipitator arranged to
wash said precipitator, and means including said duct for draining
the washing liquid from said precipitator through said grease
extractor into said trough to wash said grease extractor.
15. Ventilating apparatus for kitchen cooking equipment comprising
an exhaust duct for smoke and grease-laden air from said cooking
equipment, a grease extractor in said duct, said duct extending
upward from said grease extractor, an electrostatic precipitator in
said duct above said grease extractor, washing spray means in said
grease extractor, washing spray means for said precipitator, a
control system having a timing device for programming said washing
spray means in a wash cycle, said timing device initiating said
wash cycle by starting said washing spray means for said
precipitator, wash liquid from said precipitator draining through
said duct and grease extractor for a first washing of said grease
extractor, and said timing device thereafter stopping said washing
spray means for said precipitator and starting said washing spray
means in said grease extractor for a second washing of said grease
extractor, and further including an exhaust fan in said duct, a
start switch arranged to start said fan and energize said
precipitator, a stop switch arranged to stop said fan, deenergize
said precipitator and start said timing device, and means
controlled by said timing device to stop said washing spray means
in said grease extractor, start said fan for a drying period, and
then stop said fan and timing device.
Description
BACKGROUND OF THE INVENTION
This invention relates to a pollution-free kitchen ventilator,
particularly for restaurant use.
The ventilators of restaurant kitchens discharge large amounts of
smokey, grease-laden and malodorous air which is often
objectionable in the neighborhood. Previous kitchen ventilators
have been designed primarily to remove grease droplets which create
a fire hazard in the ventilator itself but have done little or
nothing toward preventing smoke and objectionable odors from
discharging into the atmosphere. Existing ventilators have
succeeded in providing fresh air for the workers in the kitchen and
the very effectiveness of these ventilating systems has caused even
more contamination of the outside air adjacent the restaurant.
Objects of the invention are, therefore, to provide a
pollution-free kitchen ventilator, to provide a ventilator which
removes smoke, fumes and cooking odors as well as grease from the
air discharged from the kitchen, to provide a kitchen ventilator
having an electrostatic precipitator for removing smoke and having
an activated charcoal filter and deodorizing chemical spray means
for removing cooking odors, to provide a ventilating hood having
improved fresh air makeup means arranged to sweep contaminated air
into the exhaust duct, to provide a control system having an
automatic wash and dry cycle for a grease extractor and
electrostatic precipitator, and to provide a ventilator of the type
described having an improved fire control system arranged to close
fire dampers and activate fire extinguishing and quenching
devices.
SUMMARY OF THE INVENTION
In the present construction a hood overhangs the cooking equipment
in a position to intercept smoke, fumes and grease-laden air
generated by the cooking operations. The hood has hollow walls
containing fresh air supply ducts for a number of air outlet
openings.
These openings direct streams of fresh air toward the inlet opening
of an exhaust duct, sweeping the smokey and grease-laden air into
the exhaust duct. The air in the exhaust duct passes first through
a grease extractor to remove grease droplets, then through an
electrostatic precipitator to remove smoke, then through an
activated charcoal filter to remove most of the objectionable odors
and, finally, through a deodorizing chemical spray which removes
any residual odors.
The grease extractor and precipitator are provided with hot water
and detergent washing spray means. A control system provides a wash
and dry cycle. During the wash period the ventilating fan is turned
off and the water sprays are turned on, cleaning the grease
extractor and precipitator. Then during the drying period of the
cycle the water is turned off and the fan is turned on to draw a
current of air through the grease extractor and precipitator. In
case of fire, the water sprays are automatically turned on and fire
dampers are closed in both the exhaust and air supply ducts.
The invention will be better understood and additional objects and
advantages will become apparent from the following description of
the preferred embodiment illustrated in the accompanying drawings.
Various changes may be made, however, in the details of
construction and arrangement of parts and certain features may be
used without others. All such modifications within the scope of the
appended claims are included in the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view, with parts broken away, showing a
ventilator embodying the invention;
FIG. 2 is a view on the line 2--2 in FIG. 1;
FIG. 3 is an end elevation view of the right end of the ventilator
in FIG. 1;
FIG. 4 is a fragmentary elevation view of an upper portion of the
fresh air supply duct;
FIG. 5 is a similar view of an upper portion of the exhaust
duct;
FIG. 6 is an elevation view of the left end of the ventilator in
FIG. 1 including the plumbing connections;
FIG. 7 is a perspective view of the control unit for the
electrostatic precipitator;
FIG. 8 is a fragmentary sectional view on the line 8--8 in FIG.
7;
FIG. 9 is an elevation view of the exhaust damper control unit with
parts broken away;
FIG. 10 is an exploded perspective view of the control unit for the
fresh air damper in FIG. 4;
FIG. 11 is a wiring diagram for the damper motor in FIG. 10;
and
FIG. 12 is a wiring diagram of the control system.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIGS. 1 and 2, the numeral 9 designates cooking equipment, such
as a range, which generates smoke, fumes and grease-laden air to be
removed from the kitchen. This air is captured by an open front
hood 10 having a hollow back wall 11, hollow end walls 12 and 13
and a hollow top wall 14. The hood may also be used with broilers,
soup kettles, deep fat fryers, etc.
As best shown in FIG. 1, each end wall 12 and 13 comprises spaced
apart inner and outer vertical sheets of metal 15 and 16 defining
an air inlet duct chamber 20 therebetween. As seen in FIG. 2, back
wall 11 comprises inner and outer, vertically extending sheets of
metal 21 and 22 defining an air inlet duct chamber 23 therebetween.
In a similar manner, top wall 14 comprises inner and outer,
horizontally extending, sheets of metal 24 and 25 defining an air
inlet duct chamber 26 therebetween.
Each end chamber 20 extends upward through a vertical duct section
30 which is adapted to connect at its upper end with a fresh air
supply duct 31 containing an air supply fan 32 as shown in FIG. 4.
Although both left and right ducts 30 may be supplied with fresh
air, the present system is arranged to operate satisfactorily with
fresh air supplied to only one of the ducts 30, the top of the
other then being closed by a cap 29 as shown in FIG. 1. This
provides the option of using the duct 30 which is most convenient
for connection with the exterior supply duct. The fresh air supply
duct 31 is opened and closed by the damper 33 in FIG. 4.
Each duct 30 contains a flow balancing damper 35 and a fire damper
36. Dampers 35 are adjusted when the unit is installed and
thereafter remain in fixed position. Fire dampers 36 are pivotally
mounted to close the ducts 30 in case of fire. Each damper 36 is
connected by a link 37 with an arm 38 on a main fire damper shaft
40 which will presently be described in detail. Removable front
panels 39 provide access to these dampers and the operating
linkage.
Incoming fresh air follows the paths of arrows 41 in FIG. 1. In the
lower part of chamber 20 the air flow divides, portions passing
through hollow back wall chamber 23 and hollow top wall chamber 26
to a chamber corresponding to chamber 20 in the right side end wall
13.
The inside surfaces of end walls 12 and 13 adjacent their front
ends are provided with vertically extending fresh air discharge
slots 45. The air issuing from these slots is directed rearwardly
and the flows at the opposite ends of the hood are balanced by
pivotally mounted balancing baffles 46. Baffles 46 perform the dual
function of deflecting the air from slots 45 in a rearward
direction and also acting as dampers to equalize the flows from the
left and right ends of the hood. These baffles are manually
adjusted at the time of installation and remain in fixed position
thereafter.
Similarly, the under side of hollow top wall 14 is provided with a
fresh air discharge slot 47 extending along the front edge of the
top wall. This slot is equipped with a pivotally mounted balancing
baffle 48 which directs the air flow rearwardly and also serves as
a damper to obtain the proper balance of air flows through the
three discharge openings 45, 45 and 47.
The upper edge of the metal sheet 21 which forms the front side of
hollow rack wall 11 terminates a short distance below the under
side of top wall 14 to form an exhaust air inlet throat opening 50
extending the length of the hood between its end walls 12 and 13.
The fresh air 41 discharged from outlet slots 45, 45 and 47 is
directed rearwardly toward throat 50 so as to sweep along with it
room air from the kitchen designated by arrows 51 in FIG. 2. All of
these air currents pass rearwardly over the cooling equipment 9,
sweeping fumes, smoke, odors and grease-laden air from the cooking
equipment into exhaust throat 50. This combined exhaust flow coming
from the various sources mentioned is designated by arrows 52.
From inlet throat 50 the exhaust flow 52 passes upward successively
through an exhaust duct having a grease extractor section 55,
electrical precipitator section 56, an activated charcoal filter 57
and a chemical deodorizing spray 58. At the top of the column a
collar 60 connects with an exhaust outlet duct 61 containing an
exhaust fan 62 as shown in FIG. 5.
Exhaust fan 62 has a greater flow capacity than fresh air supply
fan 32 in order to remove some air 51 from the kitchen in additon
to the total inlet flow 41. This relationship of the capacities of
the exhaust and supply fans draws into the exhaust duct a flow of
kitchen air 51 whcih not only ventilates the kitchen but also
assists in sweeping the cooking odors, fumes and smoke back into
the exhaust throat opening 50 from the front parts of the cooking
equipment.
Grease extractor 55 comprises a series of baffles projecting from
opposite sides of the exhaust passageway to create a tortuous flow
path for the air and cause grease particles to impinge against the
baffle surfaces and be separated from the air stream by centrifugal
force. The lower end of the exhaust duct terminates at a grease
trough or gutter 65 just below and inside of the inlet throat 50.
Trough 65 spans the distance between inner and outer metal sheets
21 and 22 and forms a top wall in the back inlet chamber 23. The
grease trough is equipped with a drain pipe 66.
The upper side of inlet throat 50 is defined by a downward sloping
damper baffle 67 which is pivotally mounted on shaft 40 which was
previously mentioned with reference to FIG. 1. When this baffle is
in its open operative position shown in FIG. 2, it functions as a
first grease extracting baffle, causing the entering flow of
grease-laden air to turn abruptly around its lower edge. In case of
fire, the baffle rotates clockwise with shaft 40 to form a damper
closing the exhaust passageway just inside the inlet throat 50.
Damper baffle 67 closes against a stationary baffle 68 on the metal
sheet 22. Above baffle 68 is a trough-shaped baffle 69 on a door
panel 70 hinged at 106 on the front side of the exhaust duct.
Trough 69 drains into gutter 65. These grease extracting baffles
and duct surfaces are sprayed for cleaning and fire extinguishing
purposes by spray nozzles 71 connected with a hot water and
detergent supply pipe 72. A tube 73 connected with the pipe 72
discharges a stream of hot water and detergent directly into drain
pipe 66 when the sprays are operating, to keep the drain pipe 66
free of congealed grease.
Electrostatic precipitator 56 comprises a series of cells extending
horizontally side by side the length of the hood between the
vertical end ducts 30. The cells have spaced apart vertical plates
between which the smoke-laden air passes in rising through the
exhaust duct. An electrostatic field between the plates causes
smoke in the exhaust flow to separate from the air stream and
deposit on the plates whereby smoke-free air is discharged from the
exhaust duct. Hence, the plates in the precipitating cells must be
cleaned from time to time to remove the smokey deposits that
accumulate thereon. The present arrangement provides for cleaning
the plates without removing the cells from the exhaust duct.
The precipitator is cleaned by a series of upwardly-directed, lower
washing sprays 75 and a series of downwardly-directed, upper
washing sprays 76 used alternately. The hot water and detergent
from these sprays drains down through the grease extractor 55,
providing an additional wash for the surfaces in the extractor and
passes into trough 65 for disposal through drain pipe 66. Lower
sprays 75 are generated by spray nozzles 77 in a lower supply pipe
78 and upper sprays 76 are generated by spray nozzles 79 in an
upper supply pipe 80.
After the grease and smoke have been removed as just described,
remaining fumes and odors are largely removed by the activated
charcoal filter 57 above the upper spray pipe 80. Any remaining
odors are neutralized by chemical deodorizing sprays 58 generated
by upwardly directed spray nozzles 81 in a supply pipe 82. The
active ingredient in sprays 58 may be any one of a number of
substances commonly used in room freshener deodorants. With the
grease, smoke and fumes thus removed and the cooking odors removed,
neutralized or masked, the exhaust air is clean enough to be
discharged back into the kitchen, if desired, but ordinarily it is
discharged out-of-doors in order to remove some air from the
kitchen for ventilation purposes.
Referring now to FIG. 6, spray pipes 72, 78 and 80 are supplied by
a main water supply pipe 85 having a manual shutoff valve 86. In
this main supply line are a pressure switch SW4 and a line strainer
87. The three spray pipes 72, 78 and 80 are controlled by
individual solenoid valves SV3, SV1 and SV2. Detergent from a tank
88 is added to the hot water in the three spray pipes by individual
detergent pumps DP3, DP1 and DP2. Chemical spray pipe 82 is
supplied by chemical spray pump CP1 from a chemical tank 89
containing a float switch SW5.
As shown in FIGS. 1 and 2, the electrostatic precipitator cells are
contained in four removable units 100, each having a plurality of
spaced apart vertical precipitating plates 101. Each unit 100 is
equipped with a handle 102 so that the unit may be pulled out on a
supporting rack. These units are energized by removable plugs PL1,
PL2 connected to high voltage circuit wires 103. Pairs of the units
100 are accessible behind two doors 105, each pivoted at the bottom
on a hinge 106 and equipped with a latch handle 107. In FIG. 1 the
left door 105 is open and the right door 105 is closed. When doors
105 are closed, each door engages and depresses a pair of plungers
108 and 109 in a safety control box 110.
As shown in FIGS. 7 and 8, the closing of door 105 depresses
plunger 108 to close a switch SW7 in the power supply for the
precipi-tating units. As a further safety precaution, plunger 109
normally holds open a safety grounding switch SW9 in the high
voltage circuit which energizes the circuit wires 103. When either
one of doors 105 is opened, the opening of its switch SW7
disconnects the power supply from the precipitator and spring 111
closes the grounding switch SW9.
Charcoal filters 57 are insertable and removable through doors 112
in FIGS. 1 and 2.
A snuffer fire extinguishing system is shown in FIGS. 1 and 3. In
case of fire under the hood, a carbon dioxide pressure tank 115 is
arranged to discharge fire extinguishing gas through pipe 116
connected with gas nozzles 117. The snuffer system is actuated by a
fusible link 120 carried by a holder 121 mounted on the under side
of the hollow top wall 14 of the hood as shown in FIG. 2. Fusing of
link 120 releases a tension cable 122 which passes around a pulley
123 and is connected with a cylinder valve 124 in the gas line 116.
Valve 124 is spring-tensioned to open position and is normally held
closed by cable 122 and fusible link 120.
The details of damper control unit 130 in FIGS. 1 and 2 are
illustrated in FIG. 9. As previously described, damper 67 is
mounted for rotation on a horizontal shaft 40. The damper is opened
and closed by a damper arm 131 connected with an L-shaped bracket
132 on the front of the damper whereby arm 131 has pivotal movement
on the axis of shaft 40. Arm 131 is an angle iron of L-shape in
cross section having an upper end extending into the control unit
130.
A flange 133 on the back side of arm 131 is equipped with a leaf
spring 134. A slidable control rod 135 has a pin 136 engageable
with the front side of flange 133 and a pin 137 engageable with the
back side of spring 134. The front end of rod 135 projects through
the front wall of unit 130 inside of a sleeve 138 which is slidable
on the rod. The outer end of sleeve 138 is equipped with a handle
140 having a stop 141 within the sleeve to engage the end of rod
135. The inner end of sleeve 138 is equipped with a circular latch
release plate 142.
A vertical catch plate 145 is secured to rod 135 by bolt 146. A
roller 147 on the lower end of catch plate 145 rolls on the bottom
wall of the housing 148. A compression spring 150 on rod 135 has an
outer end abutting catch plate 145 and an inner end abutting a wall
151 in housing 148. Fan switch SW3 is mounted on housing 148 in the
path of movement of catch plate 145.
A latch or trigger arm 155 extends horizontally above the rod 135,
its back end being pivotally mounted on a pin 156 in a bracket 157
on the wall 151. The front end of trigger arm 155 is connected with
a link 158 on an armature 160 in a vertical solenoid coil CL2. The
under side of arm 155 is provided with a cam surface 161 which is
engageable by release plate 142 and a notch 162 engageable with the
upper end of catch plate 145.
The parts are shown in normal operating condition with the damper
67 open as in FIG. 2. Catch plate 145 engages switch SW3 to hold it
closed and maintain operation of the fans 32 and 62 in FIGS. 4 and
5. Solenoid CL2 is deenergized, allowing its armature 160 to remain
in lower position with the upper end of catch plate 145 engaged in
notch 162 of trigger arm 155. Catch plate 145 holds spring 150
compressed with rod 135 at the leftward limit of its movement.
The damper may be closed through energization of solenoid CL2 by
the control system presently to be described or manually by pulling
handle 140 outward. Energization of solenoid CL2 raises its
armature 160 and trigger arm 155 to release the catch plate 145.
Coil spring 150 then moves rod 135 and sleeve 138 to the right,
swinging damper 67 clockwise to closed position against baffle 68.
As rod 135 moves to the right, catch plate 145 leaves the switch
SW3, causing it to open by an internal spring and shut off the fans
32 and 62.
The same result is obtained by pulling outward on handle 140.
Outward movement of sleeve 138 on the rod 135 causes plate 142 to
engage cam surface 161 and raise the trigger arm 155 to release
catch plate 145.
The damper is reopened by pushing in on handle 140. As handle 140
is pushed inward, stop 141 pushes rod 135 to the left, swinging the
damper counterclockwise. Plate 142 slides on cam surface 163,
lifting trigger arm 155 and allowing plate 142 to pass behind cam
surface 161 while catch plate 145 engages cam surface 164 and
enters notch 162 allowing trigger arm 155 to fall back to latched
position as shown. This brings latch plate 145 back into engagement
with switch SW3 to re-start the fans 32 and 62.
The damper control unit for fresh air supply damper 33 in FIG. 4 is
illustrated in FIGS. 10 and 11. The shaft 170 of motor DM1 extends
through spring housing 171 and is connected with damper shaft 172
by coupling 174. When the ventilating system is not operating,
damper 33 is held closed in vertical position against stops 173, as
shown, by spring 175. Energization of motor DM1 rotates the shafts
170 and 172 counterclockwise to open the damper to horizontal
positon, tightening the spring 175.
Cam 176 is adjusted to open motor switch 177 after 90.degree.
rotation when the damper is in horizontal, wide open position, and
apply a brake to hold the damper open. As long as motor switch 177
is closed, there is insufficient current flow through brake
solenoid 178 to make the brake effective. When switch 177 opens,
there is then sufficient current flow through brake solenoid 178 to
hold the damper open against the tension of return spring 175. This
is the normal position of the parts while the ventilating system is
operating.
Deenergization of the circuit at terminals 180, 181 releases the
brake and allows spring 175 to return the damper and motor in
clockwise rotation to closed position as shown in FIG. 10. As this
occurs, cam 176 re-closes switch 177 in preparation for the next
operation of the motor.
Control System
The control system is illustrated in FIG. 12. The system is
energized from a pair of supply wires 200, 201. A timing motor TM1
is energized by the closing of relay contacts C1 in response to the
energization of relay coil CL4. The timing motor is a conventional
device which is started by the momentary closure of contacts C1 to
rotate a one revolution cam shaft 202. When cam shaft 202 starts to
rotate, a self-contained switch, not shown, holds the timing motor
energized for one revolution and then stops the timing motor in
condition for re-starting by relay contacts C1 in a new cycle of
operation.
A fire alarm relay CL1 and damper control coil CL2 are connected in
parallel between line 200 and a wire 203. Wire 203 may be energized
from line 201 either by a manual remote fire switch SW1 or a
thermostatic switch TH1 which appears in the exhaust duct in FIG.
2. Wire 203 also energizes a time delay relay CL3 which is arranged
to close a pair of switches C2 and C3 for an interval and then open
them. Switch C2 energizes a wire 204 and switch C3 energizes a wire
205.
Timing motor cam shaft 202 actuates a plurality of switch arms C4,
C5, C6, C7, C8 and C9. These switch arms are engageable with the
contacts 211-221. Switch arm C4 is connected with line 201. Contact
212, switch arm C5 and switch arm C6 are connected together by a
wire 222. Contact 216 and switch arm C7 are connected together by a
wire 223. Contacts 218 and 219 are connected to a wire 224. Switch
arm C8 is connected to a wire 225. Contact 221 is connected to a
wire 226. Contact 213 is connected to a wire 227, contact 215 is
connected to a wire 228, contact 217 is connected to wire 204 and
contact 211 is connected to wire 205.
A pushbutton stop switch SW2 has a normally open switch arm SW2-1
and a normally closed switch arm SW2-2. The former connects timer
relay coil CL4 with wire 224 through a fuse 229 and the latter
connects timer switch arm C9 with wire 224.
A pushbutton start switch SW6 connects wire 226 with a wire 230 to
energize starter coil CL5 for the exhaust fan 62, starter coil CL6
for fresh air supply fan 32, damper motor DM1 and chemical spray
pump CP1. In series across switch SW6 are damper switch SW3, water
pressure switch SW4, chemical tank float switch SW5 and exhaust fan
starter contact C10 which is closed by starter coil CL5.
Water solenoid valve SV3 and detergent pump DP3 are energized by
wire 204. Water solenoid valve SV2 is energized by wire 228 and
detergent pump DP2 is energized by wire 227. Water solenoid valve
SV1 and detergent pump DP1 are energized by wire 205.
A wire 235 connected to timer contact 220 energizes precipitator
power pack 236 through plug PL1, door switches SW7, toggle switch
SW8 and plug PL2, all in series.
Snuffer tank pressure switch SW10 connects wire 230 with wire 240
to energize electric cooking equipment relay CL7. A solenoid gas
valve SV4 controls the cooking equipment operated by gas burners.
This valve is normally energized by contacts C12 in a gas shutoff
relay 241. Relay coil CL8 holds contacts C11 and C12 closed.
Contacts C11 are shunted by reset pushbutton switch SW12.
Start-Up
The system is put into operation by pushing in handle 140 to open
exhaust damper 67 to its FIG. 9 position and then momentarily
closing pushbutton start switch SW6 in FIG. 12. This energizes wire
230 through wire 226, contact 221, timer switch arm C9, normally
closed stop switch arm SW2-2, fuse 229, wire 224, contact 218,
timer switch arm C7, wire 223, contact 216, timer switch arm C6,
wire 222, contact 212 and timer switch arm C4 which is connected to
supply line 201. The energization of wire 230 energizes starter
coil CL5 for the relay controlling exhaust fan 62, starter coil CL6
for the relay controlling fresh air supply fan 32, damper motor DM1
which opens the damper 33 in air supply duct 31 and chemical spray
pump CP1.
The momentary energization of exhaust fan starter coil CL5 closes
contacts C10 in the exhaust fan relay to establish a holding
circuit through the normally closed switches SW3, SW4 and SW5 in
series to maintain the energization of wire 230 after pushbutton
start switch SW6 has re-opened.
Wire 230 also energizes the power pack 236 of electrostatic air
cleaner 56 through wire 225, timer switch arm C8, contact 220, wire
235, plug PL1, door switches SW7, toggle switch SW8 and plug PL2.
Power pack 236 supplies high voltage power to the plates 101 in
electrostatic cleaner cells 100. Safety grounding switches SW9 are
normally open.
Wash Cycle
The wash cycle is initiated by the momentary pushing of pushbutton
stop switch SW2. This causes switch arm SW2-2 to break the holding
circuit just described for exhaust fan relay CL5 which then opens
its relay contacts C10. This deenergizes wire 230 thereby also
deenergizing air supply fan relay CL6, the brake in damper motor
DM1, chemical spray pump CP1 and wire 225 thereby de-activating the
electrostatic air cleaner by deenergization of power pack 236.
These operations stop the ventilating functions.
The momentary pushing of stop switch SW2 also closes the normally
open switch arm SW2-1 to energize timer relay coil CL4. The
energization of relay coil CL4 closes timer motor contacts C1 to
start timing motor TM1. The operation of the timing motor maintains
the energization of its circuit for one revolution of cam shaft
202. After a short interval, timer contact arm C4 shifts from
contact 212 to contact 211, energizing wire 205 from supply line
201. Wire 205 energizes detergent pump DP1 and solenoid valve SV1
to open this valve and activate washing spray 75 to wash the
precipitator cells from below.
After a predetermined period of time, timer switch arm C4 leaves
contact 211 and returns to contact 212 which turns off the lower
wash sprays 75. At this time, timer switch arm C5 shifts to contact
213 and switch arm C6 shifts to contact 215 to energize wires 227
and 228 from supply line 201. These switch operations energize
detergent pump DP2 and solenoid valve SV2 to supply hot water and
detergent for upper wash sprays 76 to wash the precipitator cells
from above.
After another predetermined period of time, timer switch arm C5
returns to contact 214, deenergizing detergent pump DP2. Timer
switch arm C6 remains on contact 215 to hold open solenoid valve
SV2 for a further period of time to provide a hot water rinse of
the precipitator cells from above. Exhaust damper 67 remains open
during the wash and rinse operations to pass the water into trough
65 and drain pipe 66.
At the end of the rinse period, timer switch arm C6 returns to
contact 216, deenergizing wire 228 and shutting off the hot water
rinse. At this time, timer switch arm C7 shifts to contact 217
energizing wire 204 to start detergent pump DP3 and open solenoid
valve SV3 to supply hot water and detergent through spray nozzles
71 and tube 73 in the grease extractor section 55.
After this wash period, timer switch arm C7 returns to contact 218,
shutting off the wash sprays in grease extractor section 55 and, at
the same time, timer switch arm C8 shifts to contact 219 to
energize wires 225 and 230 thereby energizing the starter coils CL5
and CL6 in the exhaust fan and fresh air supply fan relays. This
circuit is maintained for a predetermined period to pass air
through the exhaust duct for drying the precipitator cells. It will
be noted that this circuit does not energize power pack 236 whereby
the precipitator cells remain deenergized and inactive. Fresh air
damper motor DM1 is energized to open damper 33 and chemical pump
CP1 is energized. At the beginning of the drying period timer
switch arm C9 leaves contact 221 to break the redundant circuit
from wire 224 through stop switch arm SW2-2 to relay contacts
C10.
After a drying period, timer switch arm C8 returns to contact 220,
stopping the fans and terminating the drying period and opening
relay contacts C10. Timer switch arm C9 returns to contact 221. All
the timer switch arms C4, C5, C6, C7, C8 and C9 have now returned
to their normal positions shown in FIG. 12 and, after a brief
further interval completing one revolution of cam shaft 202, timing
motor TM1 mechanically opens contacts C1 in its own energizing
circuit to stop the timing motor. The ventilator is then ready to
resume operation by momentarily closing start switch SW6.
Fire Control Operation
Upon closing of thermostat TH1 or remote manual fire switch SW1,
damper control solenoid CL2 is energized to close the exhaust duct
fire damper 67. This mechanical action opens damper switch SW3 to
deenergize wire 230 and fan relay coils CL5 and CL6 to stop the
exhaust and fresh air supply fans. Deenergization of wire 230 also
deenergizes power pack 236, de-activating the precipitator.
Simultaneously, time delay relay coil CL3 is energized, closing
switches C2 and C3 to energize wires 204 and 205. The energization
of these wires opens solenoid valves SV3 and SV1 and operates
detergent pumps DP3 and DP1 to operate water sprays from the
nozzles 77 and 71 for fire protection. The weight of any
accumulation of water on the closed damper 67 will slightly
compress the extended spring 150 in FIG. 9 and force the damper
open sufficiently to allow the water to escape to trough 65.
Upon deenergization of relay CL3 by the re-opening of thermostatic
switch TH1 or manual switch SW1, switches C2 and C3 remain closed
to maintain the water sprays for a preset delay period. At the end
of the preset period, switches C2 and C3 open, closing solenoid
valves SV3 and SV1 and stopping detergent pumps DP3 and DP1.
Closing switches TH1 or SW1 also energizes fire alarm relay coil
CL1 to actuate a fire alarm system.
The cooling equipment is also shut off by the closing of switches
TH1 and SW1. Relay coil CL7 controls the supply of electrical
service to electric cooking equipment and solenoid valve SV4
controls the supply of gas fuel to gas cooking equipment. Both CL7
and SV4 are normally energized by wire 230 to maintain cooking
operations when the fresh air supply and exhaust fans 32 and 62 are
running and are deenergized whenever these fans are stopped, to
shut off the cooking equipment.
In the event of a substantial decrease in pressure in snuffer tank
115 in FIG. 3, pressure switch SW10 opens and deenergizes CL7, CL8
and SV4, thereby shutting off the supply of electrical service and
gas fuel to the cooking equipment. The snuffer tank must be
re-charged and pressurized to re-close switch SW10 and enable CL7,
CL8 and SV4 to be re-energized. Upon re-starting the fans 32 and 62
by closing start switch SW6, the electrical and gas service to the
cooking equipment is reestablished by momentary closing of reset
switch SW12 to energize relay coil CL8, closing contacts C11 and
C12 and re-opening solenoid valve SV4.
Opening of either pressure switch SW4 by low water pressure or
float switch SW5 by low chemcial spray supply breaks the circuit to
CL5 to stop the fans 32 and 62 and de-activate the
precipitator.
Opening of any access door 105 to the precipitator compartment
deenergizes the precipitator power pack 236 by opening of the door
switch SW7. Simultaneously, the precipitator cells and entire high
voltage system are grounded for safety by switch SW9 in FIG. 8.
Removal of the cover from the power pack assembly 236 de-activates
the precipitator system and isolates it from line voltage by
breaking the circuit through plugs PL1 and PL2. The precipitator
may also be de-activated by opening toggle switch SW8.
Chemical spray pump CP1 and damper opening motor DM1 are activated
whenever the fans 32 and 62 are running, these devices being wired
in parallel with CL5 and CL6.
* * * * *