US2935991A - Tank venting device - Google Patents

Description

May 10, 1960 A. ARUTUNOFF TANK VENTING DEVICE 2 Sheets-Sheet 1 Filed Oct. 8, 1957 INVENTOR ARMAIS ARUTUNOFF ATTORNEY May 1960 A. ARUTUNOFF 2,935,991

' TANK VENTI-NG DEVICE Filed Oct. 8, 1957 2 Sheets-Sheet 2 55 INVENTOR ARMA IS ARUTUNOFF ATTORNEY TANK VENTHJG DEVICE Armais Arutunoif, Bartlesville, kla., assignor to Red-a Pump (Jompany, Bartlesviile, Gklan, a corporation of Delaware Application October 8, 1957, Serial No. 6S8,932 9 Claims. (Cl. 137-216) This invention relates to storage tanks for fluids of high vapor pressure and consists more particularly in new and useful improvements in a venting device for such storage tanks.

Dispensing pumps, such as now employed in gasoline filling stations, are becoming ineifective for lifting high vapor pressure gasoline from underground storage by suction because of vaporization in the pump chambers and also in the pipe lines leading from the tank to the pumps. Even when handling ordinary grades of gasoline, the pumps become ineffective during hot summer months due to the heat which causes this vaporization and this is particularly true in stations located at higher altitudes.

The primary object of the present invention is to provide automatic means for maintaining the liquid level of gasoline within the suction-lift capacity of the pumps, regardless of how low the fluid in the tank is sinking as the gasoline is dispensed from the pump.

Another object of the invention is to control and utilize the vapor pressure of the gasoline being pumped, for maintaining the liquid level of the gasoline within the suction-lift capacity of the pump.

One of the safety requirements of installations of this 2,935,991 Patented May 10, 1960 Figure 4 is a fragmentary elevational view showing a modification of the invention embodying an auxiliary heating device for initiating vaporization when required.

In the drawings, 5 represents a horizontally disposed underground storage tank of more or less conventional form, provided in its upper wall with flanged openings 6,

' 7, 8 and 9 for respectively installing a vertically disposed type is that no gasoline should rise above the suction opening of the pump when the pump is not in operation. Another requirement is that no vapors be permitted to rush out of the tank when it is opened to be refilled or to 'be metered. It is therefore a further object of the invention to accomplish the desired results while complying with these safety requirements.

' Still another object of the invention is to provide a venting device for high vapor pressure fluids wherein the vent valve is under the control of a specially designed float having substantially the same specific gravity as the gasoline or other fluid in the tank, the weight of said float and in turn its effective weight on the valve, being responsive to variations in the liquid level in the tank.

A still further object of the invention is to provide a venting device of this character, including means for manually operating the valve irrespective of its float control.

Still another object of the invention is to provide in a tank of this nature, equipped with a venting device, means for preventing gases from blowing into the filling opening of the tank in the event that the operator overlooks the manual control of the venting device preparatory to filling the tank.

With the above and other objects in view which will appear as the description proceeds, the invention consists in the novel features herein set forth, illustrated in the accompanying drawings and more particularly pointed out in the appended claims.

Referring to the drawings in which numerals of like character designate similar parts throughout the several views,

Figure l is a side elevational view of an underground storage tank embodying the present invention, certain portions being broken away and shown in section to illustrate the working parts of the invention.

discharge pipe 10, metering pipe 11, filling pipe 12 and vent pipe 13. The discharge pipe 10 and the metering pipe 11 extend into the tank to within a relatively short distance from its underside while the filling pipe 12 and vent pipe 13 are connected directly to the top wall of the tank and communicate with the interior at this point.

The upper ends of all four of these pipes terminate below ground level, within respectivewells 14, 15, 16 and 17 which are preferably provided with removable closures at ground level. The discharge pipe it) is adapted to be connected at 18 to a dispensing pump (not shown). The upper ends of the pipes 11 and 12 are provided with conventional caps or closures as shown. The vent pipe 13 carries at its upper end a connection 19 which may be secured to a conventional vent tube (not shown) which usually towers above ground level.

As best seen in Figure 2, the vent pipe 13 is threaded at its lower end into the flanged opening 9 and thereby firmly connected to the tank 5. The upper end of the vent tube 13 is threaded into a housing 20 enclosing a centrally located relief valve generally indicated by the numeral 21. The valve assembly 21 comprises an annular seat member or ring 22 secured between two retaining rings 23, inset in the inner peripheral wall of the housing, the seating ring 22, preferably being sealed as at 24 with respect to said inner periphery of the housing. The valve member or body per se 25, is preferably in the form of a circular disk of suitable sealing material having a diameter to overlie and seat against the top extremity of the central passageway 26 in the ring 22, its underside being provided with a'depending conical body 27 for guiding the valve into seating engagement with the passageway 26.

The ring 22 supports the threaded upper end of a guide tube 28 which as shown in Figure 1 is concentric with vent pipe 13 and depends into the interior of the tank 5, to substantially midway of the diameter of the tank, the upper end of the guide tube being provided with radial ports or openings 29 which communicate with the interior of the tank 5 through the annular space between the guide tube 28 and the interior of the vent pipe 13.

An elongated float 30 or constraining load means for valve body 27, is composed of wood or other suitable material having substantially the same specific gravity as the gasoline or other fluid being controlled, and is suspended from the valve body 27 by a flexible connection '31..In the form of the invention here shown, this connection consists of a chain 31 connected between a stem 32 depending from the body 27 and a loop 33 fixed to the upper end of the float 30. Thus, the weight of the float 30 through the chain 31 causes a downward force to be exerted on the valve member 25, the vertical position and movement of the float 30 being maintained by the enveloping guide tube 28. The float 30 preferably extends from its point of connection 33 to within a relatively short distance of the lower wall of the tank, and its effective seating weight is immediately responsive to the liquid level within the tank.

In order to provide for the manual control of the valve assembly 21 so that the vent can be opened preparatory to filling the tank, a crank arm 34 is fixed to the outer end of a short shaft 35 extending through a gland 36 in the wall of the housing 29, the inner end of said shaft carrying an eccentrically disposed arm 37. The arm 37 projects horizontally through a vertical slot 38 in a stem 39 secured to the upper face of the valve member by adjusting nuts 49. Preferably, a pull rod 41 connected at 42 to the crank arm 34 and carrying a pull ring 43 at its upper end, is conveniently positioned within the well 17 (Fig. l) and retained in vertical position by. a guide member 43a fixed to the wall of the Well 17.

As shown in Figure 3 in dotted lines, an upward pull on the pull rod 41 swings the crank arm 34 about its axis, rotating the shaft and causing the eccentric arm 37 to lift the valve body 25 through its engagement with slot 38 in the stem 39. Upon release of the ring 43 and pull rod 4-1 the weight of the float 30 causes the seating of the valve 25, to normally close the passageway 26.

One side of the wall of housing 20, below the valve seat ring 22, is provided with a radial passageway 44 which is connected to a vacuum relief valve body 45 I which is preferably screw threaded into the housing 20. A ball valve member 46 normally seats to close a port 47 which leads into a dual purpose tube 48 for the purpose hereinafter described.

Returning to Figure 1, it will be seen that the filling pipe 12 is provided with a spring loaded conical valve 4-9 operated by the tension of spring 50 to normally close a passageway 51 leading from the interior of the tank 5 to the fill pipe 12. This is a lightcheck valve assembly and the tension of spring 513 is so limited that a column of a few inches of gasoline in fill pipe 12 is all that is required to open the valve when filling the tank if the latter has already been manually vented to atmosphere by the vent mechanism previously described. However, if the tank has not been vented and the pressure in the tank is higher than atmospheric pressure, the pressure within the tank automatically maintains the valve 51 in closed position to prevent the filling of the tank.

The operation of the mechanism thus far described is as follows: Assuming that the tank 5 has been filled to a predetermined level with a gasoline of high vapor pressure, for example, the vent valve assembly 21 is seated by the Weight of the float 30. The float is so weighted that it permits the valve member 25 to open or rise from its seat on ring 22 before the vapor pressure in the tank becomes suflicient to lift fluid to the suction opening of the pump attached to the dispensing pipe 10 and gasoline is prevented from rising above the pump intake while the tank is full and the liquid level stands high in the tank.

As the fluid in the tank is being pumped out through the dispensing pipe 10 and the level of the gasoline is lowered, the weight on the gravity actuated valve member 25 is progressively increased by the weight of the float which, as before stated, is of substantially the specific gravity of the gasoline or other fluid in the tank. By maintaining the valve assembly 21 in closed position, the escape of vapors is precluded, thus causing the vapor pressure in the tank to increase but not to exceed that which is required to keep the fluid at the level close to the level of the pump intake.

Thus, the force of the weight of the float 30 acting on the release valve member 25 is approximately zero when the tank is full and the float is fully submerged. When the tank is empty, the full weight of the float acts upon the release valve to maintain it in closed position, said weight varying in response to the changing positions of the liquid level in the tank and being equal to the weight of a column of gasoline of a cross sectional area corresponding to the cross sectional area of the valve.

When the liquid content of the tank 5 has been pumped out and it becomes necessary to fill the tank, the vapor content of the tank is vented to atmosphere by actuating the manual control through the pull rod 41 and ring 43, thus lifting the valve member 25 01f of its seat to freely vent the tank. The purpose of the safety valve 49 in the filling pipe has already been described. Thus, should the operator overlook the manual operation of the relief valve assembly 21 prior to filling the tank, the valve 49 prevents gases from blowing through the filling opening and pipe 12.

To assure that the vapor pressure developed in the tank is suflicient, for example, two or three psi, particularly for locations where summer heat vaporizes the gasoline in the pump chambers and even in the supply pipe, the insulation thickness of the top covering of the tank may be made sufliciently shallow to permit some heat to reach through the metal parts of the tank to build up the vapor pressure therein. In the case of existing installations where tanks are better insulated from heat than the pipelines leading to the dispensers, a small amount of propane, butane or the like may be injected into the tank without being concerned that the liquid will overflow the pump. For this purpose, the vacuum release valve body 45 is provided with the tubing 48 which may be connected to a source of butane or propane. The

injected fluid enters the housing 20, passes downwardly into the tank 5 through the vent pipe 13, increasing the vapor pressure in the tank.

In some instances it may be desirable to provide a heating unit for increasing the vapor pressure in the tank. An example of such a heating unit is shown in Figure 4 where it will be seen that a tube 52, open at its lower extremity, adjacent the corresponding end of the float 30, is connected at its upper end as at 53, to the guide tube 28. A heating coil 54 having lead wires 55, to a power line, surrounds the tube 52, a switch 56 and actuating arm 57, operable by the lowering of the float 30, controlling the application of heat through the coil 54. As the liquid level in the tank lowers and the float descends, the hermetically enclosed switch 56 is actuated by the float, heating the liquid column in the tube 52. The heated vapors rise to the connection 53 and flow into the guide tube 28, escaping through openings 29 and tube 13 into the area of the tank above the liquid level therein. This increases the vapor pressure above the liquid level and thereby maintains the liquid level of gasoline in the tank within the suction lift capacity of the pump irrespective of the height of the liquid level in the tank.

By employing a float or constraining load means for the vent valve, which is weightless when the tank is full and becomes weighted when the tank is empty, the valve is operated by a change of Weight as distinguished from a change of position of thefloat as with ordinary floats which usually undergo a relatively long travel. In other words, an almost negligible movement of the float of the present invention, caused by its changing Weight, actuates the valve with maximum efficiency.

From the foregoing it is believed that the invention may be readily understood by those skilled in the art without further description, it being borne in mind that numerous changes may be made in the details disclosed without departing from the spirit of the invention as set forth in the following claims.

I claim:

1. A storage tank for pressurized liquids, including a filling connection, a dispensing tube extending vertically from a point in said tank in proximity to the bottom thereof, to the exterior for connection to a pump, vent means for controlling the vapor pressure above the liquid in said tank to maintain a predetermined liquid level in said dispensing tube, within the suction-lift capacity of a pump connected thereto, said vent means comprising a vapor release valve in the upper portion of said tank, and a vertically disposed float suspended from said valve, of substantially the same specific gravity as that of the liquid in said tank, said float and valve being responsive to the lowering of the liquid level in said tank to progressively restrict said vent means and build up the vapor pressure in said tank.

2. A storage tank as claimed in claim 1, wherein the upper portion of said tank is provided with a vent opening, said vapor release valve comprising a valve seat in said opening, a valve body for gravity engagement with said seat, said vertical float being elongated and suspended from said valve body in the liquid in said tank, for normally closing said valve, guide means in said tank, aligned with said opening, for maintaining said float and its movement in a vertical direction, and manually operable means exterior of said tank for lifting said valve body in opposition to the weight of said float.

3. A storage tank as claimed in claim 1, wherein the upper portion of said tank is provided with a vent outlet opening, said vapor release valve comprising a valve seat in said opening, a valve body for gravity engagement with said seat, a vertical guide tube suspended from said valve sent into the liquid in said tank, said vertical float being elongated and slidably retained in said tube, and a flexible connection suspending said float from said valve body.

4. A storage tank as claimed in claim 1, wherein the weight of said float acting on said valve is approximately zero when the tank is full and the float fully submerged, and the force of the full weight of said float acts on said valve when the tank is empty.

5. A storage tank as claimed in claim 1, including a check valve in said filling connection, said check valve being normally closed in response to vapor pressure de veloped in said tank and releasable by the weight of a predetermined column of fluid in said filling connection, in the absence of vapor pressure in said tank.

6. A storage tank as claimed in claim 1, including means for supplementing the vapor pressure in said tank.

7. A storage tank as claimed in claim 1, including means for connecting said tank to a source of normally gaseous fluid for supplementing the vapor pressure in said tank. 7

' 8. A storage tank as claimed in claim 1, wherein said tank is provided with an auxiliary heating device for vaporizing a portion of the fluid in said tank to supplement the vapor pressure therein.

9. A storage tank as claimed in claim 1, including a combined vacuum release valve and vapor injection device associated with said vent means.

References Cited in the file of this patent UNITED STATES PATENTS 753,861 Duck Mar. 8, 1904 1,279,216 Anthony Sept. 17, 1918 1,731,684 Renfrew Oct. 15, 1929 2,251,086 Van Dyke et a1 July 29, 1941 2,745,426 Ponsar May 15, 1956

Images