Liquid dispensing and vapor recovery system

[57] ABSTRACT

A liquid dispensing and vapor recovery system in which an underground storage tank is connected to a first conduit for delivering a liquid, such as gasoline, to a vehicle gasoline tank, or the like, under the force of a pump disposed in the storage tank. A second conduit is connected to the first conduit and to the storage tank for diverting a portion of the gasoline in the first conduit back to the storage tank while forming a reduced pressure zone in the second conduit. A recovery vessel is connected to the vehicle tank for receiving the vapors froth the latter tank and separating same into relatively heavy and relatively light portions. The heavy vapors are passed directly into the storage tank and the light vapors are drawn into the second conduit and are partially absorbed by the gasoline flowing in the latter conduit before being passed into the storage tank.

Claims, 2 Drawing Figures

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U.S. Patent oct. 21,1975

Sheet 1 of 2

3,913,633

FIG. I.

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U.S. Patent Oct. 21,1975

Sheet 2 of 2

3,913,633

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3,913,633

LIQUID DISPENSING AND VAPOR RECOVERY SYSTEM

BACKGROUND OF THE INVENTION

This invention relates to a liquid dispensing and vapor recovery system and, more particularly, to such a system in which liquid is dispensed from a storage tank to a receptacle while vapors from the receptacle are drawn to the storage tank.

With the increased emphasis on preventing pollution of the atmosphere, attention has been directed to minimizing the introduction of gasoline vapors into the atmosphere from both permanent type underground storage tanks for the gasoline, and from the vehicles to which the gasoline is ultimately dispensed.

Gasoline vapors can easily be recovered from underground storage tanks by providing a separate vapor return line which connects the storage tank to the transport truck which periodically fills the tank. In this manner, the gasoline introduced into the tank from the transport truck will displace the vapors and force them through the vapor recovery line to the truck whereby they are ultimately disposed of either by burning or through compression - refrigeration systems.

However, it has been extremely difficult to devise a satisfactory vapor recovery system from the gasoline tanks of vehicles due to the fact that the configurations of the tanks vary to a wide degree and to the fact that many of the tanks have open vents in their fill necks which allows the vapors to be displaced through the vents to the atmosphere during a fill cycle. This problem may become even more acute since some state and federal regulations may very well ultimately require full recovery of vapors from existing automobile gasoline tanks, whether vented or not.

Previous proposals to recover the gasoline vapors from automobile tanks have included what is commonly referred to as a balanced displacement system in which the gasoline entering the tank forces the vapors through a separate line to the storage tank. However, this system has been less than satisfactory, largely due to the difficulty in creating a proper seal between the gasoline dispensing and recovery nozzle and the automobile tank.

Although it has also been suggested to use a vacuum pump along with a compressor and chiller assembly to remove the vapors from the vehicle tanks, this type of installation has proved to be relatively expensive and therefore impractical.

In copending U.S. patent application Ser. No. 400,555, filed by Kirk Fowler and Elmer M. Deters on Sept. 25, 1973, and assigned to the same assignee of the present invention, a gasoline dispensing and vapor recovery system is disclosed which overcomes the abovementioned problems by providing an injector for establishing a reduced pressure zone in response to fluid flow from the storage tank to the vehicle receptacle, with the reduced pressure zone functioning to draw the vapors from the receptacle back to the tank. Although this design has proven to be satisfactory, the size limitation of the injector has imposed limitations on the capacity of the system, thereby preventing use of the system in relatively large installations.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a liquid dispensing and vapor recovery system in which liquid is dispensed from a storage tank to a receptacle while vapors in the receptacle are recovered and delivered back to the storage tank.

It is a further object of the present invention to provide a liquid dispensing and vapor recovery system of the above type in which an injector is used to create a vacuum in response to the dispensing of the liquid from the storage tank to the receptacle, and is utilized to draw the vapors from the receptacle back to the tank.

It is a further object of the present invention to provide a liquid dispensing and vapor recovery system of the above type which can be used in relatively large installations yet utilizes an injector of a relatively small size and capacity.

It is a more specific object of the present invention to provide a liquid dispensing and vapor recovery system of the above type in which a recovery vessel is provided in the line connecting the vehicle tank to the storage tank for receiving the vapors from the vehicle tank and separating them into relatively light portions which are fed to the injector, and relatively heavy portions which are fed directly to the storage tank, to thus enable an injector of a relatively small size and capacity to be utilized.

It is a further object of the present invention to provide a liquid dispensing and vapor recovery system of the above type which is relatively simple in operation and relatively low in cost.

Toward the fulfillment of these and other objects, the system of the present invention comprises storage means for the liquid, first conduit means adapted to connect said storage means to a receptacle, and pumping means for pumping said liquid from said storage means through said first conduit means and to said receptacle, wherein the improvement comprises second conduit means connected to said first conduit means and to said storage means for diverting a portion of said liquid in said first conduit means back to said storage means, and means for forming a reduced pressure zone in said second conduit means in response to liquid flow through said second conduit means, a recovery vessel for receiving the vapors from said receptacle and separating said vapors into a relatively light portion and a relatively heavy portion, and means connecting said vessel to said reduced pressure zone for drawing the relatively light vapors from said vessel through said second conduit means for passage into said storage means, said recovery vessel being directly connected to said storage means for directly passing said relatively heavy vapors into said storage means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial schematic, partial elevational view of a service station installation having a gasoline dispensing and vapor recovery system of the present invention utilized therein; and

FIG. 2 is an enlarged, partial sectional, partial elevational view of a portion of the installation of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As an example of the use of the liquid dispensing and vapor recovery system of the present invention, it will be described in connection with a gasoline dispensing installation for use in service stations or the like. Such an installation is illustrated in FIG. 1 and includes an underground tank 10 for storing a quantity of gasoline

3,913,633 which is delivered to one or more pedestals 12 through delivery lines 14 and 14a, under the force of a submersible pump unit 16 disposed in the tank.

A casing 18 is attached to the tank 10 and extends upwardly therefrom to connect the tank to a discharge head, or manifold, 20 which is preferably disposed below ground level in a well 22.

The pedestals 12, the pump 16 and the manifold 20 are all described in detail in U.S. Pat. No. 3,183,723. Therefore, for the convenience of presentation, the structural details of these units are not shown in the drawings and will be described only generally as follows.

The pump unit 16 is an electrical operated centrifugal type which operates to draw the gasoline into the unit through a plurality of intake ports disposed at the bottom thereof, and to force the gasoline upwardly around a sealed electrical drive motor to the manifold 20, in a conventional manner.

The manifold 20 supports the upper portion of the pump unit 16 while permitting the electrical connections for the drive motor to be brought outwardly for connection to the proper controls. It is understood that an adapter unit, or packer, is supported within the manifold housing and has an inlet chamber communicating with the outlet of the pump unit and an outlet chamber adapted for registration with the line 14. The packer also includes a port between the inlet chamber and the outlet chamber which cooperates with a check valve to permit the flow of gasoline from the pump 16 to the line 14 while preventing flow in the opposite direction, also in a conventional manner.

An injector assembly 30 is connected in the line 14 between the manifold 20 and the pedestals 12 and is better shown with reference to FIG. 2. In particular, the injector assembly 30 is preferably disposed below ground level in a well 32 and is connected to the line 14 by a by-pass conduit 34 which registers at one end with the line 14. As a result, upon flow occurring through the line 14, a portion of the gasoline is diverted through the conduit 34 and to the injector 30. A nozzle 35 and a venturi 36 are formed in the injector 30 in communication with the by-pass conduit 34 to form a reduced pressure zone at the throat portion of the venturi in a conventional manner. A conduit 37 registers with the outlet of the venturi 36 and extends into the tank 10 where it terminates near the floor thereof. A conduit 38 is connected to the injector 30 and communicates with the nozzle 35 and with the abovementioned reduced pressure zone. The other end of the conduit 38 is connected to an underground recovery vessel 40, to be described later.

As shown in FIG. 1, the line 14 extends from the manifold 20 to the vicinity of each of the pedestals 12 whereby it is connected to same via branch lines 14α. In a similar manner, the recovery vessel 40 is connected to the pedestals 12 by means of a line 42 and branch lines 42α.

A hose assembly 44 extends from each of the pedestals 12 with each assembly including an inner hose surrounded by a spaced, coaxial, outer hose. As shown schematically in FIG. 1, the inner hose of each hose assembly 44 is connected to the gasoline delivery line 14α and the annular space between the inner hose and outer hose is connected to the vapor recovery line 42α within each respective pedestal 12. A dispensing unit 46 is connected to the free end of each hose assembly

44, it being understood that each unit 46 includes a dispensing nozzle connected to the inner hose of its respective hose assembly and a vapor recovery conduit connected to the annular space between the inner and outer hoses of each assembly. Also, each dispensing unit is operated by a manually operated valve 46α, in a conventional manner.

A support and switch assembly 48 is associated with each pedestal 12 and is adapted to support its respective dispensing unit 46, with the switch operating to actuate the pump unit 16 upon release of the dispensing unit 46 therefrom in a conventional manner. Although not shown in the drawings, it is understood that the pedestals 12 can be provided with the proper linkage, interlock valves, meters, etc., in accordance with conventional designs.

As shown in FIG. 2, the recovery vessel 40 is disposed in the well 32 and is in the form of a cyclone separator having an inlet 52 connected to the vapor recovery line 42, a first outlet 54 extending below the well 32 and emptying directly into the storage tank 10, and a second outlet 56 connected to the line 38 extending to the injector 30. It is understood that the vessel 40 operates in a conventional manner to create a centrifugal action which causes the relatively heavy vapors entering the inlet 52 to fall to the bottom of the vessel and pass directly into the tank 10. Also, the relatively light vapors will tend to rise in the vessel and exit through the outlet 56 into the line 38 for passage into the injector 30. A plate 58 having a slot 60 formed therethrough is provided in the upper portion of the vessel 40 to create a high velocity draw through the vessel and thus promote the introduction of the vapors from the vehicle tank shown schematically in FIG. 1, through the line 42, and into the vessel.

A check valve 62 is provided in the line 14 to insure that gasoline flow will occur only in the direction indicated by the solid arrows in FIG. 2, while a check valve 64 is provided in the line 38 to insure that vapor flow through the latter line will occur only in the direction indicated by the dashed arrows in FIG. 2.

In operation, upon an operator releasing one of the dispensing units 46 from its support and switch assembly 48 on a pedestal 12, the pump unit 16 will be actuated to pump gasoline from the tank 10 through the manifold 20 and the line 14 to the pedestal 12. From the pedestal 12 the gasoline will pass through the inner hose of the delivery hose assembly 44 whereby, upon manual actuation of the valve 46a associated with the dispensing unit 46, it will be introduced into the gasoline tank of the vehicle.

A portion of the gasoline flowing through the line 14 will be diverted through the line 34 and will pass into the injector 30 where it passes through the nozzle 35 and the venturi 36 before passing into the line 37 and back to the tank 10. As a result, a reduced pressure zone will be formed in the injector 30 which is transferred, via the line 38, the recovery vessel 40, and the lines 42 and 42α, to the annular space between the inner and outer hoses of the delivery hose assembly 44.

This reduced pressure zone, plus the force of the gasoline as it displaces the vapors from the vehicle tank, will cause the vapors to pass from the tank into the space between the inner and outer hoses of the delivery hose assembly 44, through the lines 42α and 42, and into the vessel 40. In the vessel 40 the vapors will be subjected to a centrifugal action which causes the rela3,913,633 tively heavy vapors to pass downwardly and out through the exit 54 directly into the storage tank 10. The relatively light vapors will tend to rise in the vessel 40 and will pass through the slot 60 in the plate 58, through the outlet 56, and into the line 38 for passage into the injector 30. In the injector 30, the vapors pass through the nozzle 35 and the venturi 46 where they are partially absorbed by the gasoline entering the injector 30 from the line 34. The resulting mixture then passes from the injector 30, through the line 37 and into the lower portion of the tank 10 where even more absorption will occur as the vapors rise upwardly through the gasoline in the tank. In this manner, some absorption of the vapors is achieved while permitting an injector of relatively low capacity to be used.

At the tank 10 the vapors supplied to the tank directly from the recovery vessel 40, as well as those from the line 37 that were not absorbed, will either condense of will be recovered by the transport truck for supplying gasoline to the storage tank in the manner discussed above.

In addition to the advantages discussed above, it is noted that, in the event of a failure of the injector 30, the recovery vessel 40 will enable the system to revert to a balanced displacement system in which the vapors would be drawn to the tank 10 solely by virtue of their displacement from the vehicle tank, thus minimizing any potential damage to the system. Also, the vapor recovery system of the present invention limits the amount of negative pressure of vacuum that will be applied to the vehicle tank by virtue of the recovery vessel 40, thus eliminating the chance of damage to the tank.

According to an alternate embodiment of the present invention, an optional condenser system 70 may be provided which receives excess vapors from the recovery vessel 40, via a line 72, and condenses the vapors in accordance with conventional practice, before passing same through a line 74 back to the line 37 for passage into the tank 10. Since this type of condenser system is well known in the art, it will not be described in any further detail.

It is thus seen that the present invention provides an effective and safe means of recovering vapors in a vehicle tank without polluting the atmosphere.

It is understood that several modifications may be made in the foregoing system without departing from the scope of the invention. For example, the system can be adapted for vapor recovery only by simply terminating line 14 at the vicinity of the check valve 62 to permit all of the gasoline pumped from the tank into the line 14 to be passed through the injector 30. Also, the system of the present invention is not limited to the dispensing of gasoline and the recovery of gasoline vapors but could be applied to any installation, such as chemical plants, or the like, in which vapor recovery is desired.

Of course, variations may be made in the foregoing system without departing from the scope of the invention as defined by the appended claims.