U.S. patent number 3,926,230 [Application Number 05/478,519] was granted by the patent office on 1975-12-16 for recovery of flammable vapors.
Invention is credited to Edward L. Brown, Eric L. Pridonoff, Marvin L. Stary.
United States Patent |
3,926,230 |
Stary , et al. |
December 16, 1975 |
Recovery of flammable vapors
Abstract
A system for preventing escape of vapors into the atmosphere
when filling gasoline or the like into a tank, and including means
for collecting vapors from the vicinity of the filling nozzle, or
nozzles, adsorbing the vapors onto an adsorbent substance such as
activated charcoal, and then utilizing the vapors in admixture with
air as the sole fuel for driving a combustion engine. The engine
may be started intermittently, preferably in response to each
actuation of the dispensing nozzle.
Inventors: |
Stary; Marvin L. (Claremont,
CA), Brown; Edward L. (Claremont, CA), Pridonoff; Eric
L. (Pasadena, CA) |
Family
ID: |
23900273 |
Appl.
No.: |
05/478,519 |
Filed: |
June 12, 1974 |
Current U.S.
Class: |
141/45; 123/518;
141/98; 95/146; 96/130 |
Current CPC
Class: |
B67D
7/0476 (20130101) |
Current International
Class: |
B67D
5/01 (20060101); B67D 5/04 (20060101); B65B
031/06 () |
Field of
Search: |
;141/41-45,52,59,287,290,98 ;55/387,88,62,74,316,182,385NS
;220/85VR,85US,86R ;62/50-54 ;123/133,136 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bell, Jr.; Houston S.
Attorney, Agent or Firm: Green; William P.
Claims
We claim:
1. Apparatus comprising:
a liquid dispensing system including tank means for holding a
flammable liquid, hose means for dispensing said liquid, and
discharge nozzle means on said hose means;
means for collecting flammable vapors of said liquid from said
dispensing system and including collection line means for
withdrawing vapors from the vicinity of said nozzle means during a
dispensing operation;
adsorption chamber means through which said collected vapors and
intermixed air are passed and containing a substance adapted to
adsorb said vapors;
an engine;
means for feeding said collected vapors to the intake of said
engine as its only fuel in a quantity sufficient to drive said
engine solely by the combustion of said vapors, said vapor feeding
means acting to progressively desorb vapors from said substance for
delivery to the engine; and
means for delivering air to the intake of said engine with said
collected vapors in a controlled total air-vapor ratio which is
combustible in the engine to drive it solely by burning of said
vapors.
2. Apparatus as recited in claim 1, including an air compressor
driven by said engine.
3. Apparatus as recited in claim 1, in which said vapor feeding
means include a line through which said vapors are delivered to
said engine, and a pressure regulator in said line.
4. Apparatus as recited in claim 1, in which said vapor feeding
means include a first line for delivering vapors from said chamber
means to the engine, said air delivering means including a second
line for delivering air to said engine, there being valve means for
controllably varying the proportions of vapor and air delivered
through said first and second lines to produce said combustible
air-vapor mixture.
5. Apparatus as recited in claim 1, including a starter for turning
over said engine, and means for energizing said starter
intermittently.
6. Apparatus as recited in claim 1, including a pressure opening
valve adapted to pass an increased amount of air to said engine in
response to a predetermined increase in pressure of said
vapors.
7. Apparatus as recited in claim 1, in which said vapor feeding
means include a first line for delivering vapors from said chamber
means to the engine, and a pressure regulator in said line; said
air delivering means including a second line for delivering air to
said engine, adjustable metering valve means in said second line, a
third line bypassing said metering valve means, and a pressure
opening valve in said third line adapted to open and pass an
increased amount of air to said engine in response to an increase
in the pressure of said vapors upstream of said pressure regulator
of the vapor feeding means.
8. Apparatus as recited in claim 7, including a check valve in said
second line upstream of said third line and metering valve means,
and additional metering valve means in said third line.
9. Apparatus as recited in claim 1, in which said vapor collecting
means include vacuum pump means for drawing vapors through said
collection line means and delivering said vapors to said adsorption
chamber means.
10. Apparatus as recited in claim 1, in which said vapor collecting
means include vacuum pump means for drawing vapors through said
collection line means and delivering said vapors to said adsorption
chamber means, there being a return line for delivering vapors from
said pump means back to said tank means.
11. Apparatus as recited in claim 1, in which said vapor collecting
means include vacuum pump means for drawing vapors through said
collection line means and delivering said vapors to said adsorption
chamber means, there being a return line for delivering vapors from
said pump means back to said tank means, and a valve connected into
said return line adapted to permit flow of vapor but prevent flow
of liquid therethrough in a direction away from said tank
means.
12. Apparatus as recited in claim 1, in which said vapor collecting
means include vacuum pump means for drawing vapors through said
collection line means and delivering said vapors to said adsorption
chamber means, there being a pressure regulator valve between said
pump means and said adsorption chamber means.
13. Apparatus comprising:
a liquid dispensing system including tank means for holding a
flammable liquid, hose means for dispensing said liquid, and
discharge nozzle means on said hose means;
means for collecting flammable vapors of said liquid from said
dispensing system and including collection line means for
withdrawing vapors from the vicinity of said nozzle means during a
dispensing operation;
adsorption chamber means through which said collected vapors and
intermixed air are passed and containing a substance adapted to
adsorb said vapors;
an engine;
means for feeding said collected vapors from said chamber means to
the intake of said engine to burn therein;
a vapor flow line through which vapor may flow between said tank
means and said adsorption chamber means; and
a valve connected into said vapor flow line and adapted to permit
flow of vapor but prevent flow of liquid therethrough toward said
chamber means.
14. Apparatus comprising:
a liquid dispensing system including tank means for holding a
flammable liquid, hose means for dispensing said liquid, and
discharge nozzle means on said hose means;
means for collecting flammable vapors of said liquid from said
dispensing system and including collection line means for
withdrawing vapors from the vicinity of said nozzle means during a
dispensing operation, and vacuum pump means for drawing vapors
through said collection line means;
adsorption chamber means to which said vapors are discharged by
said vacuum pump means and containing a substance adapted to adsorb
said vapors;
a pressure opening valve between said pump means and said
adsorption chamber means adapted to be opened by the pressure of
said pump means but to close under a reduced pressure when the pump
means are not operating;
an engine;
means for feeding vapors from said chamber means to the engine to
burn therein; and
means for delivering air to the intake of said engine.
15. Apparatus as recited in claim 14, including a pressure
regulator valve between said pump means and said pressure opening
valve acting when said pump means are in operation to maintain a
regulated pressure at the inlet side of said pressure opening valve
high enough to open the latter.
16. Apparatus as recited in claim 14, including a pressure
regulator valve between said pump means and said pressure opening
valve acting when said pump means are in operation to maintain a
regulated pressure at the inlet side of said pressure opening valve
high enough to open the latter, a vapor line extending from a point
between said pump means and said regulator valve back to said tank
means, and a float valve in said vapor line preventing liquid flow
therethrough in a direction away from said tank means.
17. Apparatus as recited in claim 14, including a pressure
regulator valve between said pump means and said pressure opening
valve acting when said pump means are in operation to maintain a
regulated pressure at the inlet side of said pressure opening valve
high enough to open the latter, a vapor line extending from a point
between said pump means and said regulator valve back to said tank
means, a float valve in said vapor line preventing liquid flow
therethrough in a direction away from said tank means, a vent to
atmosphere communicating with said tank means, and a pressure
relief valve on said vent.
18. Apparatus as recited in claim 17, in which said vapor feeding
means include a first line for delivering vapors from said chamber
means to the engine, and a pressure regulator in said line; said
air delivering means including a second line for delivering air to
said engine, adjustable metering valve means in said second line, a
third line by-passing said metering valve means, and a pressure
opening valve in said third line adapted to open and pass an
increased amount of air to said engine in response to an increase
in the pressure of said vapors upstream of said pressure regulator
of the vapor feeding means.
19. Apparatus comprising:
dispensing means for delivering a flammable liquid into a tank, and
including a dispensing conduit and a discharge nozzle;
manually actuated means for controlling the operation of said
dispensing means;
means for withdrawing flammable vapors from the vicinity of said
nozzle;
chamber means containing an adsorbent substance through which said
vapors are passed in a relation causing adsorption of said vapors
onto said substance;
an engine receiving vapors from said substance and within which
said vapors are burned;
a starter for starting said engine; and
means for energizing said starter in response to operation of said
manually actuated means.
20. Apparatus as recited in claim 19, in which said dispensing
means includes a liquid pump for forcing said flammable liquid
through said nozzle and into said tank, said manually actuated
means serving when actuated to commence operation of said liquid
pump.
21. Apparatus as recited in claim 19, including delay means acting
to terminate energization of said starter after it has been in
operation for an interval of time.
22. Apparatus as recited in claim 19, in which said dispensing
means include a liquid pump for forcing said flammable liquid
through said nozzle and into said tank, said manually actuated
means serving when actuated to commence operation of said liquid
pump, there being time delay means acting to terminate energization
of said starter after it has been in operation for an interval of
time, said means for withdrawing vapors including a vapor suction
line, a valve in said line, and a vacuum pump, there being means
for opening said valve and energizing said vacuum pump in response
to actuation of said manually actuated means.
23. Apparatus comprising:
dispensing means for delivering a flammable liquid into a tank, and
including a dispensing conduit and a discharge nozzle;
manually actuated means for controlling the operation of said
dispensing means;
means for withdrawing flammable vapors from the vicinity of said
nozzle and including a vacuum pump;
chamber means containing an adsorbent substance through which said
vapors are passed in a relation causing adsorption of said vapors
onto said substance; and
means for activating said vacuum pump to withdraw vapors from the
vicinity of said nozzle in response to actuation of said manually
actuated means.
24. Apparatus as recited in claim 23, in which said dispensing
means include a liquid pump for forcing said flammable liquid
through said nozzle, said manually actuated means serving when
actuated to commence operation of said liquid pump.
25. Apparatus comprising:
dispensing means for delivering a flammable liquid into a tank, and
including a dispensing conduit and a discharge nozzle;
manually actuated means for controlling the operation of said
dispensing means;
means for withdrawing flammable vapors from the vicinity of said
nozzle and including a vapor suction line and a valve controlling
flow therethrough;
chamber means containing an adsorbent substance through which said
vapors are passed in a relation causing adsorption of said vapors
onto said substance; and
means for opening said valve in response to actuation of said
manually actuated means.
26. Apparatus as recited in claim 25, in which said dispensing
means include a liquid pump for forcing said flammable liquid
through said nozzle, said manually actuated means serving when
actuated to commence operation of said liquid pump.
27. The method that comprises:
collecting flammable vapors from a flammable liquid dispensing
system having a tank and at least one dispensing conduit with a
discharge nozzle;
adsorbing at least some of said collected vapors onto an adsorbent
material;
delivering said collected vapors and air to an engine in a ratio
combustible in the engine; and driving said engine solely by the
combustion of said collected vapors.
28. The method as recited in claim 27, including turning said
engine over and attempting to start it intermittently to burn up
any accumulated vapors.
29. The method as recited in claim 27, including returning some of
said collected vapors back to said tank.
30. The method that comprises:
operating a liquid dispensing system at different times to dispense
a flammable liquid from a tank through a conduit and nozzle;
collecting flammable vapors from said system;
adsorbing at least some of said collected vapors onto an adsorbent
material;
delivering said collected vapors and air to an engine to burn
therein; and
turning said engine over and attempting to start it at said times
when the dispensing system is operated.
31. Apparatus comprising:
dispensing means for delivering a flammable liquid into a tank, and
including a dispensing conduit and a discharge nozzle;
means for withdrawing flammable vapors from the vicinity of said
nozzle;
chamber means containing an adsorbent substance through which said
vapors are passed in a relation causing adsorption of said vapors
onto said substance;
an engine receiving vapors from said substance and within which
said vapors are burned;
a starter for starting said engine; and
timer means for automatically energizing said starter at
predetermined timed intervals to turn said engine over.
32. Apparatus comprising:
dispensing means for delivering a flammable liquid into a tank, and
including a dispensing conduit and a discharge nozzle;
means for withdrawing flammable vapors from the vicinity of said
nozzle;
chamber means containing an adsorbent substance through which said
vapors are passed in a relation causing adsorption of said vapors
onto said substance;
an engine receiving vapors from said substance and within which
said vapors are burned;
a starter for starting said engine; and
means for energizing said starter at different times and including
means for automatically terminating said energization of the
starter after it has been in operation for an interval of time.
33. Apparatus as recited in claim 1, including an electrical
generator driven by said engine.
Description
BACKGROUND OF THE INVENTION
This invention relates to improved apparatus and methods for
filling a flammable liquid such as gasoline into a tank, as for
example into the fuel tank of an automobile at a service station,
and doing so in a manner preventing escape of vapors from the
liquid into the atmosphere.
There have in the past been devised various types of apparatus for
preventing escape of vapors while a tank is being filled. These
systems usually include a vapor pickup line which takes suction
from the location of the dispensing nozzle by which the liquid is
being filled into the tank. In some instances, the accumulated
vapors are then refrigerated to convert them to liquid form for
return to a main storage tank. In other types of equipment, the
vapors may be separated from intermixed air by passage over an
adsorbent substance, such as activated charcoal, which will
selectively adsorb the fuel vapors and permit the cleaned air to
escape into the atmosphere.
Certain arrangements of this latter type are shown in U.S. Pat. No.
3,581,782 issued June 1, 1971. One form of the invention shown in
that patent is adapted for use on a fuel delivery truck, and
ultimately withdraws the adsorbed vapors from the activated
charcoal to the intake side of the delivery truck engine for
burning in the engine along with its driving fuel.
SUMMARY OF THE INVENTION
The present invention discloses an adsorption type system, in which
there is provided an engine which is driven solely by combustion of
the recovered vapors. These vapors are intermixed with air in a
controlled air-vapor ratio assuring essentially complete conversion
of the fuel to carbon dioxide and water, while making available for
use in any desired manner the mechanical output power produced by
the engine. The means for delivering the vapors and air to the
engine may include appropriate valve means for controllably varying
the proportions of vapor and air to attain optimum combustion.
A vapor pump initially withdraws the vapors from the vicinity of
the dispensing nozzle or nozzles, and delivers the vapors to the
adsorptive material, with a return line being provided for return
of some of the vapors back into the main storage tank from which
the liquid is being withdrawn. A float valve in this return line
may serve to prevent flow of liquid therethrough toward the
adsorbent material in the event that the storage tank is
inadvertently over-filled. A pressure operated valve may also be
provided in the line going to the adsorbent material, to prevent
the engine from drawing vapors from the main storage tank, and
operating on those vapors, during periods when the adsorbent
material is being regenerated but no fuel is being dispensed from
the discharge nozzle.
A starter is provided for the engine, to intermittently commence
operation of the engine if and when enough vapors are present in
the adsorptive material to drive the engine. In a presently
preferred form of the invention, the starter is energized
automatically for a short interval each time that the dispensing
equipment is actuated to deliver liquid into a tank.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features and objects of the invention will be
better understood from the following detailed description of the
typical embodiments illustrated in the accompanying drawings, in
which:
FIG. 1 is a representation of a service station installation
embodying the invention;
FIG. 2 is an enlarged fragmentary showing of one of the fuel
dispensing nozzles of the FIG. 1 apparatus;
FIG. 3 is a flow diagram illustrating the vapor recovery system of
the FIG. 1 apparatus;
FIG. 4 shows the electrical control circuitry of the FIG. 1
apparatus; and
FIG. 5 shows a variational circuit for controlling energization of
the starter.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to FIG. 1, I have represented generally at 10 in
that figure a service station `island` on which a number of fuel
dispensing units or pump assemblies 11 are located for filling
gasoline or other fuel in measured quantities into a fuel tank 12
of an automobile or other motor vehicle represented at 13. As is
conventional, there may be several such dispensing units at the
same station, receiving fuel from one or more underground storage
tanks 14 through lines 15. The tanks 14 are filled from delivery
trucks through vertical fill pipes 16, which extend upwardly to the
surface of the earth and have removable caps 16'.
Each of the dispensing units 11 contains a pump 17 which is driven
by an electric motor 18 and acts when energized to force fuel into
and through the usual flexible hose 19 to a dispensing nozzle unit
20 adapted to project into the fill tube or neck 21 of the vehicle
tank 12, (See FIG. 2). The nozzle unit 20 is manually manipulated,
and contains a dispensing valve 22 which is actuated by a trigger
type control element 23 to start and stop the discharge of fuel
from the discharge end 24 of the nozzle.
When the nozzle element 20 of a particular one of the dispensing
units 11 is not in use, the nozzle is inserted into and supported
within a recess 25 in the housing 26 of the unit 11. The nozzle is
locked within this recess and against removal therefrom by a lever
27, which must be swung manually, as between the full line and
broken line positions represented diagrammatically in FIG. 4, to
release the associated nozzle for removal from housing 26. This
swinging movement of element 27 actuates a double pole electric
switch (28 in FIG. 4) between open and closed positions, to close
the electric circuit to the associated pump motor 18, and thereby
commence operation of the pump 17 for delivering fuel through hose
19 to the vehicle tank when the nozzle 20 is opened. As will appear
at a later point, this actuation of switch 28 also serves in the
present apparatus to energize certain equipment relating to the
vapor recovery system with which the present invention is
especially concerned.
For preventing the escape of fuel vapors into the atmosphere while
fuel is being delivered from nozzle 20 into the vehicle tank, each
of the nozzles 20 carries a vapor pickup element 29 (FIG. 2), which
is connected to a flexible suction hose 30 extending alongside and
parallel to the main fuel delivery hose 19 for connection to a
solenoid valve 130 and flame arrestor 230 within the interior of
the associated dispenser unit housing 26. When a particular one of
the solenoid valves 130 is energized and therefore open, it places
the connected suction hose 30 in communication with an underground
suction line 31 leading to a vapor pump 32 driven by an electric
motor 33 to create a sub-atmospheric pressure in line 31 and
element 29 on the nozzle, acting to withdraw fuel vapors and some
air from the vicinity of nozzle 20 and thereby prevent escape of
any of the vapors outwardly past the nozzle during a filling
operation. Element 29 on the nozzle contains an appropriate suction
passage, which preferably has an annular open end at the locations
designated 34 in FIG. 2, so positioned as to be received within the
filling tube 21 of the vehicle tank during a filling operation.
At the location 35, the suction line 31 has a downwardly inclined
portion leading to a point 36 of communication with a drain line 37
through which any liquid contained within the suction line can
drain back into tanks 14 past a swing check valve 38. Vapors in
line 31, however, are taken by vacuum pump 32, as indicated
previously.
The vapor recovery equipment of FIGS. 1 to 4 includes also one or
more adsorption chambers 40, containing beds of an adsorbent
substance 41, such as activated charcoal, capable of adsorbing the
flammable gasoline vapors and thereby separating the vapors from
any air intermixed therewith, and then permitting escape of the
cleaned air into the atmosphere at 42. At various times, these
adsorbed vapors are withdrawn from the material 41 by reverse flow
of clean atmospheric air through the beds, and are then utilized as
the sole fuel for driving an internal combustion engine 43, whose
power output may typically be utilized for driving an air
compressor 44 acting to compress air into an accumulation tank 45.
The compressed air from this tank 45 may be withdrawn as needed for
driving various types of air actuated equipment normally employed
in a service station or the like. Alternatively, the unit
represented at 44 in FIG. 1 may be an electrical generator, acting
to generate electric power for use at the station. Regardless of
whether the driven unit 44 is a compressor, generator, or other
piece of equipment, that driven unit is preferably of a type to
impose an essentially constant load on the engine at all times when
in operation.
The engine 43 may be a conventional reciprocating piston and
cylinder type internal combustion engine, except that it does not
require a carburetor since the fuel as supplied to the engine is
already in vapor form. In most instances, it is contemplated that
for a service station installation a relatively small engine,
typically a two cylinder four-stroke-cycle engine, will be capable
of converting all of the accumulated vapors to water and carbon
dioxide to thereby prevent their admission into the atmosphere. The
engine is adapted to be started by a starter-generator device 46
which when energized electrically will turn the engine over at
starting speed, but when de-energized and driven by the engine will
serve as a generator for producing an output voltage and current
for recharging the engine battery 47. A conventional starter
solenoid 48 is used for energizing the starter, in association with
the usual voltage regulator 49 and ammeter 50. A governor
represented at 143 may be used to regulate the engine speed.
With reference now to the flow diagram of FIG. 3, there preferably
are provided at both the inlet and outlet sides of vapor pump 32 a
pair of flame arresters 51 and 52, which may consist merely of
canisters containing masses of porous but heat adsorbent material
capable of preventing propagation of any flame which may be
developed past the locations of these flame arresters. Beyond
arrester 52, the slightly pressurized vapor from pump 32 passes
first through a trim valve 53 which is manually adjustable to vary
the rate of flow through a line 54 and connected line 55 to a
pressure regulator valve 56 and pressure opening valve 156, from
which the vapors flow through a line 57 into an inlet end of a
first of the adsorbent beds 41. The valve 56 maintains a
predetermined regulated pressure slightly above atmospheric
pressure at its discharge side, so long as vapor at a pressure
above atmospheric reaches its intake side. Valve 156 is normally
closed when its inlet is at atmospheric pressure, but automatically
opens when its inlet pressure increases to a predetermined slightly
super-atmospheric value. Regulator 56 maintains a pressure in
excess of that opening pressure of valve 156 whenever pump 32 is in
operation.
The vapors from line 57 may be injected into the adsorbent material
through an elongated hollow screen element 58 or the like,
projecting into the interior of the adsorbent material and capable
of discharging the vapors over a somewhat extended area into the
bed. From the location of screen 58, the vapors and some intermixed
air flow first upwardly through one of the beds of adsorbent
material, and then through a line 59 into the lower portion of the
next successive bed and surrounding chamber or tank 40, to flow
upwardly therethrough to the discharge line 42 leading to the
atmosphere. By the time the air has reached line 42, all of the
vapors have been completely adsorbed onto the activated charcoal or
other adsorbent material, and the air in line 42 is therefore
completely clean of such vapors.
When engine 43 is in operation, atmospheric air is drawn from line
42 through the beds of material 41, to desorb the vapors
progressively from that material, and then deliver the vapors and
some intermixed air through a preferably elongated outlet screen
158, a line 61, a pressure regulator valve 62 and a manually
actuated shut off valve 63 to the intake 64 of engine 43. A flame
arrestor 65 may be provided at the intake of the engine, again to
prevent propagation of any flame in either direction past this
location, while still permitting free and unobstructed flow of the
vapors to the engine. The pressure regulator valve 62 maintains an
essentially constant pressure at its discharge side 66, to assist
in controlling the delivery of a proper air-vapor mixture to the
engine. The inlet 58 and outlet 158 in the first bed 41 are offset
or spaced from one another so that vapors can not flow directly
between the inlet and outlet without passing through some of the
adsorbent material. The provision of this buffer zone of adsorbent
material between the inlet 58 and outlet 158, in conjunction with
the various automatic pressure controls, permits simultaneous
adsorption and desorption on the same carbon bed, and also permits
the engine to keep running with or without dispensing, and even
while tanks 14 are being filled.
For intermixture with the vapors, a second intake line to the
engine is provided at 67, taking suction from the atmosphere. The
air from line 67 passes first through an air filter 167, then
through a check valve 68 acting to permit air flow only downwardly
in FIG. 3 (but to prevent reverse flow or loss of vapor when the
engine is not running), and then through a manually adjustable trim
valve 69, before intermixture at 70 with the vapor in line 61.
Additional air can be supplied to the engine through a by-pass line
267, past a trim valve 169 and a pressure operated valve 170
responsive to the pressure at the intake side of valve 62. Valve
170 is normally closed during operation of the equipment, but may
be automatically opened by a predetermined increase in pressure in
beds 41 to pass additional air to the engine.
The two valves 63 and 69 are so adjusted manually as to deliver to
engine 43 a combustible mixture of vapors and air, having a proper
air-fuel ratio for efficient burning within engine 43, when valve
170 is closed and the pressure in beds 41 is at its normal valve.
Under these conditions, it is found that, once the valves 63 and 69
have been properly set for an appropriate air-fuel ratio, say
between about 11 to 1 and 13 to 1, this ratio will automatically
remain fairly constant, regardless of the amount of accumulated
vapor which may be present on the material 41. So long as any vapor
remains in the beds, the engine will continue to operate
efficiently, and will then automatically cease operation when all
of the adsorbed vapors have been removed from the material 41.
If the pressure in the beds at any time becomes excessive, valve
170 opens automatically to pass increased air to the engine, in a
metered amount determined by the setting of trim valve 169, and
just sufficient to compensate for the increased vapor flow and
maintain essentially the same predetermined air-fuel ratio to the
engine.
As a final assurance against discharge of any unwanted substances
into the atmosphere, the exhaust line 71 from engine 43 may contain
a catalytic exhaust purifier represented at 72, for oxidizing any
small amount of unburned hydrocarbons or carbon monoxide which may
remain in the exhaust, and thereby discharging to the air only
carbon dioxide and water vapor.
During any interval when fuel is being withdrawn from one or both
of the underground storage tanks 14 by one of the units 11, and is
being filled into a vehicle tank 12, some of the vapor discharged
by pump 32 is fed back into the storage tanks through a line 73, to
take the place of the removed liquid. A float valve 74 may be
connected into this line 73, to prevent reverse flow of liquid
through line 73 and toward beds 41 in the event that the storage
tanks 14 are at any time accidentally over-filled. This valve 74
normally permits vapor flow in either direction through the valve,
but automatically closes by float action if liquid reaches the
level of valve 74 from the tanks, to thereby protect material 41
from the liquid.
Valve 74 may be connected to the storage tanks most expeditiously
by connecting valve 74 to a vent line 75, which is connected to the
upper portions of the tanks 14 and extends upwardly to an upper end
76 at which a pressure-vacuum vent valve 77 communicates with the
atmosphere. This valve 77 is normally closed, but will open as a
pressure relief valve in response to the attainment of an excessive
pressure in the tanks 14 and line 75, to thereby discharge fuel and
vapors to the atmosphere and prevent damage to the system as a
result of such excessive pressure.
In addition to the various electrical components already discussed,
the circuitry of FIG. 4 includes also a time delay relay 78 whose
coil 79 is connected in parallel to the vapor pump motor 33, as
shown, and whose movable contact 80 is normally closed but adapted
to be opened by energization of coil 79 to break the circuit to a
coil 81 of a second rleay 82, whose normally open contact 83 is
adapted to close the circuit from battery 47 to the coil 84 of the
starter solenoid unit 48.
To now describe a cycle of operation of the illustrated equipment,
assume first of all that the underground tanks 14 have been filled
with a flammable fuel to be dispensed, and that the engine 43 is
initially not running. If, then, it is desired to fill the tank 12
of a motor vehicle with fuel from one of the dispensing units 11,
an operator first actuates the lever or arm 27 of that particular
unit 11 to free the associated nozzle 20 for removal from its
position of confinement within recess 25, and then places the
nozzle into the fill tube 21 of the vehicle tank. The actuation of
lever 27 also closes an associated switch 28 of that particular
unit 11 (FIG. 4), to thereby close a circuit from a power source 87
(typically 115 volt-60 cycles) through the switch 28 to an
associated one of the solenoid valves 130 and the associated fuel
delivery pump motor 18. The motor 18 commences to drive its
connected fuel pump 17, to pressurize the fuel within hose 19, and
to cause delivery of the fuel into tank 12 when trigger element 23
of the nozzle assembly is actuated.
The closure of any of the switches 28 also acts to close a circuit
to the vapor pump motor 33, to commence withdrawal of a mixture of
vapors and air from the nozzle location through one of the suction
lines 30 and through the associated solenoid valve 130 which has
been energized and opened by actuation of the switch 28. In
addition, the closure of switch 28 closes the circuit to coil 79 of
the time delay relay 78, which is so designed as to open the
normally closed contact 80 of that relay after a predetermined
delay interval of say fifteen seconds. During that interval, the
contact 80 of time delay relay 78 closes a circuit from the power
soruce 87 to coil 81 of the second relay 82, to thereby pull the
normally open contact 83 of that relay to its closed condition,
energizing starter solenoid coil 84 from 12-volt battery 47, and
closing the contact 184 of the solenoid in a manner energizing
starter motor 46 from battery 47. Thus, as soon as any one of the
switches 28 is closed, starter motor 46 commences to turn engine 43
over at starting speed, and continues to turn it over until
expiration of the timed delay period for which relay 78 is set, at
which time coil 79 of relay 78 opens contact 80 of that relay, to
deenergize relay 82, starter solenoid 48, and the starter 46
itself.
If at the time of this actuation of the engine by starter 46, there
is sufficient vapor accumulated in chambers 40 to drive the engine,
the rotation of the engine will create a vacuum in line 64 (FIG. 3)
acting to draw vapors and some air from chambers 40 through line 61
to the engine, and simultaneously drawing air through line 67 to
the engine. Assuming that valve 170 is closed, the settings of
valves 63 and 69 are such that the air-fuel mixture which reaches
the engine is within the proper range to cause the engine to run by
combustion of the fuel vapor within the cylinders of the engine.
During this operation, some air is drawn downwardly through line 42
into and through the adsorptive material 41, for delivery from the
bottom of the second bed of adsorptive material into line 61
leading to the engine. The air thus flowing downwardly desorbs the
flammable vapors from the material 41 progressively, in a
proportion which, it is found, does not vary substantially in spite
of variations in the amount of vapors present in the bed. The
air-fuel ratio to the engine therefore remains within a proper
range to continue operation of the engine, once started, until
substantially all of the adsorbed vapors have been removed from the
material 41. Thus, if there are enough vapors to commence operation
of the engine on any particular timed actuation of the starter, the
engine will continue to run until substantially all of the vapors
have been desorbed from the beds of activated charcoal or the like.
When all of the accumulated vapors have been removed, the engine
automatically stops for lack of further fuel, and remains stopped
unitl the next successive dispensing operation, at which time the
closure of one of the switches 28 causes the starter to again
operate for a timed interval, and start the engine if at that time
enough vapors have accumulated to run the engine. If as previously
indicated the pressure in beds 41 and line 61 ever reaches the
predetermined excessive value for which valve 170 has been set,
this valve opens and admits enough extra air to compensate for the
increased vapor concentration in line 61 and thereby still maintain
a properly combustible air-fuel ratio in the engine intake.
During the entire time that any one of the liquid dispensing pumps
17 is in operation, the vapor pump 32 is driven continuously to
withdraw vapors from the vicinity of the dispensing nozzle 20, and
to force those vapors, slightly compressed, past valves 56 and 156
and into the adsorptive beds 41. Any air which is withdrawn from
the nozzle region with the vapors flows upwardly through the
chambers 40 for discharge to the atmosphere as clean air through
line 42, with all of the flammable vapors being adsorbed onto the
material 41 before reaching line 42. The pressure opening valve 156
prevents negative pressure being drawn on the storage tanks 14 when
engine 43 is in operation and tending to draw a vacuum but fuel is
not being dispensed through any of the nozzles 20. As soon as any
of the nozzles is opened and dispensing commences, the resultant
slightly positive or super-atmospheric pressure at the inlet to
valve 156 opens that valve to permit vapor flow to beds 41.
When fuel is being filled into the tanks 14 through the fill lines
16, it is preferred that the delivery trucks be of a type having
built-in vapor recirculation systems, to themselves withdraw from
the tanks at least some of the vapor being displaced by the added
liquid. Any excess vapor may then pass through the float valve 74
and valves 56 and 156 into the carbon beds, for adsorption onto the
beds and discharge of clean air to the atmosphere. If the gasoline
storage tanks are over-filled, the float check valve 74
automatically closes to prevent the flow of liquid gasoline into
the carbon beds or vapor pump. If the gasoline delivery is made
with a truck which does not have a vapor return, excessive pressure
may build up in the vent line 75, but pressure regulator 56 will
prevent more than the normal vapor flow to beds 41, and the excess
vapor will be discharged to atmosphere through relief valve 77.
The intermittent operation of engine 43 acts through compressor 44
to build up a supply of compressed air in tank 45, which may be
used as needed in a distribution system at the service station or
other facility. Any other power takeoff system, such as a generator
or alternator driven by the engine, may similarly utilize
substantially all of the energy of the collected vapors for useful
purposes, without discharge of any pollutants into the air.
FIG. 5 shows diagrammatically a changed portion of the electrical
circuit of a variational form of the invention, which form may be
considered as identical with that of FIGS. 1 through 4 except that
the two relays 78 and 82 are deleted, and in lieu of these relays
there is provided a timer 90 for controlling operation of a
starter-generator 46a corresponding to the starting unit 46 of FIG.
4. Timer 90 may include a clock which acts at predetermined timed
intervals to close the circuit to coil 84a of starter solenoid 48a
(corresponding to solenoid 48 of FIG. 4), and thereby energize the
starter 46a for a predetermined interval (say fifteen seconds),
following which the timer breaks the circuit leaving the engine
operating if sufficient vapor is present, and with the engine then
continuing to operate until depletion of all adsorbed vapors. At
that time, the engine stops until the next energization of the
starter by timer 90. As an example, timer 90 might perhaps be set
to start the motor once each day, so that the vapors would
accumulate in the activated charcoal for a full day and then be
desorbed by operation of the engine, then accumulate for another
day, etc. In lieu of the timer 90 or the relays of FIG. 4, it is
also contemplated that other means may be provided for
intermittently starting the engine, which means may include
manually actuated switches for starting the engine under the direct
control of an operator if desired. If at any time in any of the
forms of the invention the starter is energized when the engine is
already running, the operation of the engine is not affected by
such energization of the starter.
In the presently preferred form of the invention, the operational
pressures at different points in the system, and the operating
pressures of the various automatic valves, may be as follows:
1. Intake pressure to pump 32 is preferably between about -5"WC and
-20"WC desirably about -10"WC.
2. Discharge pressure from pump 32 is preferably between about
+5"WC and +20"WC, desirably about +10"WC.
3. Pressure maintained by regulator valve 56 at its outlet side is
slightly positive (above atmospheric), preferably between about
1"WC and 3"WC, and optimally about 2"WC.
4. Pressure opening valve 156 opens at a slight positive pressure,
not greater than, and preferably somewhat less than the regulated
outlet pressure of valve 56, the opening pressure of valve 156
desirably being between about 0.5"WC and 1.5"WC, optimally about
1"WC.
5. Pressure maintained by regulator valve 62 at its outlet side is
desirably between about 0"WC and -4"WC, and for best results about
-2"WC.
6. Valve 170 preferably opens at a positive pressure between about
0"WC and 1"WC, for best results about 0.5"WC.
7. Relief valve 77 opens at a pressure above the normal discharge
pressure of pump 32, and above the normal pressure at the outlet
side of valve 53, the opening pressure of valve 77 desirably being
between about 10"WC and 18"WC, for best results about 14"WC.
While certain specific embodiments of the present invention have
been disclosed as typical, the invention is of course not limited
to these particular forms, but rather is applicable broadly to all
such variations as fall within the scope of the appended claims. As
one example of a possible variation, there may be substituted for
the individual fuel delivery pumps in the various dispensing units
11 a single pump delivering fuel to a number of the dispensing
units 11 and typically located near one of the tanks 14.
* * * * *