US3675614A - Fluid level alarm device for tanks and the like to minimize spills of oil and other environmental pollutants - Google Patents

Abstract

A gas operated audible alarm device is provided to signal the advent of an overflow condition in oil tanks and the like to minimize the hazards of environmental pollution from oil and chemical spills during tank filling operations. The device has a float operated pneumatic valve positioned at a predetermined upper limit of fluid level in a receiving tank, which valve controls the passage of an inert gas from a supply source to a gas operated whistle or horn. A multiplicity of such alarm devices are adapted to be actuated from a common supply header to monitor an entire field or complex of receiving tanks.

Description

United States Patent Ward et al. 51 July 11, 1972 s41 FLUID LEVEL ALARM DEVICE FOR 598,985 2/1898 Fleming ..73/301 x TANKS AND THE LIKE TO MINIMIZE {1223 52 :33; THE 1 tap ANTS 1,898,546 2/1933 Kellet 3,066,641 12/1962 Buell, Jr. et a1 ..1 16/1 12 [72] j 'f' gzgg g? FOREIGN PATENTS OF. APPLICATIONS I I 9 2914 Ontario Ave., Baltimore, Md. 21234 $28,745 6/1955 ltaly ..1 16/1 12 [22] Filed: Primary Examiner-Louis J. Capozi [21] Appl. No.: 87,427 Ar!0meyBirch & Birch ABSTRACT [52] [1.5. CI ..1 16/118, 73/307, 73/319,

1 1 1 2 137 553 A gas operated audible alarm device IS provided to slgnal the 51 Int. Cl ..G0ll23/00 advent wl'dition in Oil and 58 1 Field of Search ..ll6/109,l10, 112,118; minimize hm 9 and 73 05 0 30-;I 309 3 I6 3 7 3 chemical spills during filling OPClatlOnS. The device 3 137/409, 41 1, 413, 423, 428, 429, 430, 434, 445 Operated neumatic valve pos tioned at a predetermlned 558 upper limit of fluid level in a receiving tank, which valve controls the pe of an inert gas from a supply source to a gas operated whistle or horn. A multiplicity of such alarm devices [56] References Cad are adapted to be actuated from a common supply header to rr STATES PATENTS monitor an entire field or complex of receiving tanks. 291,272 1/! 884 1 37/429 X 6 Chills, 4 Drawing Figures l2 A! 2 T l L 2 (DRY) GAS 30 4 2 l4 PMEN'TEDJIJL 1 1 m2 3, 6 7 5.6 14

2B .727. I 30 I g z (DRY) GAS l 4 3p 38 26 136A 1 2e |4 3 J I 32 2s 36 L, J 34 30 h A 30 T0 N2 SUPPLY 7 y 4 INVENTOR JOHN T. WARD ALLEN B. KELLER BY 6M+3M ATTORNEY FLUID LEVEL ALARM DEVICE FOR TANKS AND THE LIKE TO MINIMIZE SPILLS OF OIL AND OTHER ENVIRONMENTAL POLLUTANTS This invention relates to audible alarm means and more particularly to an audible alarm means for oil tanks and the like which produce a warning signal when the fluid level in a tank reaches a predetermined maximum.

Many spills of oil and other undesirable substances which polute the environment are occasioned by human error. One of the most common forms of human error is the failure to detect that the fluid level in a tank being filled with oil or other fluid chemicals is immediately proximate to the overflow point of the tank.

Attempts have been made in the prior art to provide float actuated or pressure actuated audible alarm devices which provide an indication of the advent of an overflow condition in a storage tank. Such storage tanks may be fixed or ambulatory land-based tanks or located on cargo barges or other vessels.

Due to the highly flammable and/or reactive nature of many fluids contained in such storage tanks, electrical alarm systems are necessarily unduly expensive since they must be both corrosion resistant and spark free. Furthermore, alarm systems utilizing compressed air and compressed carbon dioxide as the activating medium for an audible whistle or similar device have numerous drawbacks based upon environmental problems such as freezing or unsafe reactions with the fluids contained in the tanks being monitored by the alarm devices.

ls, therefore, an object of the present invention to provide a new and novel audible alarm device for indicating the advent of an overflow fluid level in storage or cargo tanks which is foolproof in operation and has optimum environmental capabilities regarding both the internal and external environments of the tank being monitored.

Another object of the present invention is to provide a new and novel audible alarm device having an optimally minimum number of working parts and optimally minimum down-time due to service problems.

Still another object of the present invention is to provide a new and novel audible alarm device and system for a plurality of such devices having a central source of pressurized actuating fluid feeding a plurality of such audible alarm devices whereby an entire network of cargo or storage tanks can be successfully monitored to indicate the advent of overflow conditions in any given tank.

These and other objects of the invention will become more fully apparent with reference to the following specification and drawings which relate to a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a top plan view of an audible alarm device of the present invention and a portion of a system embodying same;

FIG. 2 is a front plan view of the audible alarm device of FIG. 1;

FIG. 3 is a side plan view of the audible alarm device and portion of the system illustrated in FIG. 1; and

F IG. 4 is a schematic illustration of an audible alarm device of the present invention installed in a storage or cargo tank illustrating the internal and external connections of the alarm with respect to the storage tank and the alarm actuating fluid supply system.

Basically, the invention comprises a float actuated valve interconnecting a source of dry nitrogen gas under pressure through the said valve to a whistle or horn device adapted to be actuated by gas under pressure. The alarm device is adapted to be positioned in the upper extremities of the interior of a cargo or storage tank whereupon the float is responsive to the liquid level in the cargo or storage tank to actuate the valve and release nitrogen under pressure to the whistle when the level in the tank approaches an overflow condition. If a multiplicity of tanks is involved, each tank is provided with an individual audible alarm device connected to a supply header or manifold which in turn is connected to a common source of pressurized dry nitrogen to drive the individual whistles on the audible alarm devices when the fluid level in any given tank approaches an overflow condition.

Referring in detail to the drawings and more particularly to FIGS. 1, 2 and 3, the audible alarm device l0 of the present invention is shown as comprising a main mounting bracket 12 having a box frame 14 rigidly affixed thereto. Extended from the box frame 14 is a float constraining cage device 16 which is comprised of an upper support ring 18 fixed to the lower extremity of the box frame 14, a plurality of dependent struts 20 welded or otherwise fixed to the upper support ring [8 and a circular bottom plate 22 welded or otherwise fixed to the lower end of the vertical struts 20. The vertical struts 20 are substantially of identical length such that the lower support plate 22 is substantially parallel to the plane of the upper support ring 18.

A spherical float 24 is freely constrained within the float cage 16 and normally seats on the lower support plate 22 so long as the level of the fluid in the tank being monitored is below the lower support plate 22.

Mounted in the box frame 14, through the bracket 12. is a valve assembly 26. The valve assembly 26 includes a plunger operated on-off type pneumatic valve 28 in-line mounted in a pneumatic manifold pipe 30 which extends from an input portion 30A through the main mounting bracket 12 through the valve 28 and thence back through the mounting bracket 12 to an output section 30B. Plunger 32 extending vertically above the valve 28 in response to a predetermined liquid level in a tank in which the alarm device 10 is mounted.

The remainder of the actuating linkage for the valve 28 comprises an upstanding bifurcated pivot bracket 34 mounted on the body of the valve 28, in which a bell crank 36 is pivoted at a point 38 intermediate the ends thereof. Bell crank 36 is provided with an engaging foot 36A on one side of the pivot point 38 which is adapted to engage the plunger 32 on the valve 28. The other end of the bell crank 36 is provided with a contact foot 36B which is adapted to engage the spherical float 24 when that float rises to a sufficient point in the float cage 16 in response to the presence of an overly high fluid level in the tank in which the alarm device 10 is mounted.

The input side 30A of the pressure manifold 30 is connected to a supply header 40 which in turn is connected to a supply 42 of dry nitrogen gas under pressure. The output section 30B of the pressure manifold 30 is directly connected to a gas operated whistle 44.

Referring now to FIG. 4 the audible alarm device It], described in FIGS. 1, 2 and 3, is shown with the main mounting bracket 12 affixed to the side wall 46 in the upper dome of a tank T. While the device 10 is shown in a vented tank T as symbolized schematically by the vent tube V, located above the alarm device 10 in the dome of the tank T, it is contemplated that this device may be used in any type of tank vented or unvented, so long as the float 24 of the device 10 is positioned to respond to a predetermined fluid level in the tank T.

It is of the utmost importance that the supply of pressurized inert gas be dry nitrogen gas in the present invention and its application. This is occasioned by the fact that ordinary compressed air and many other readily available compressed gases would create highly flammable conditions within the tank due to their oxygen or other reactive gas content should there be a malfunction in the valve assembly 26 or the pressure manifold 30 within the tank T.

Furthermore, a commonly available inert gas, namely, carbon dioxide, has inherently bad qualities for alarm devices of this type due to environmental problems. For example, should there be an undue amount of moisture in the air or should the temperatures be realitively low in the atmosphere surrounding the tanks, the whistle 44, when subjected to a blast of carbon dioxide therethrough in order to sound the alarm, would freeze and preclude proper actuation.

Dry nitrogen, on the other hand, is readily available and will not create freezing conditions when released from a pressurized source to pass through a whistle under extreme ranges of heat, humidity, and temperature. Neither will it react with the fluid contents of the tank T to endanger life, limb and/or property due to adverse chemical reactions or fire within the tank T.

To illustrate the effectiveness of the audible alan'n device 10, for example, if dry nitrogen under 40 lbs. per square inch pressure is permitted to energize a conventional steam or air whistle 44, noise levels of at lease 99 disibels or greater can be produced. This is sufficient for industrial applications or other high noise level environments.

In a preferred embodiment for the prevention of oil spills from storage and cargo tanks, the spherical float 24 can be constructed from copper and dimensioned to be l inches in diameter, thereby providing approximately l5 lbs. of lift in response to an overly high fluid level in the tank T. The mounting bracket 12, box frame 14 and the float cage 16 can be constructed of stainless steel and the air valve 26 can be a standard bronze air valve. The use of half-inch heavy duty galvanized pneumatic lines for the manifold 30 and the main supply header 40 is also contemplated.

In operation, referring to FIGS. 1, 2, 3 and 4, the audible alarm device is mounted in the tank T such that a liquid level Ll (indicated by the lowermost dotted line position in the tank T in FIG. 4) or less will have no effect on the audible alarm device 10. However, when the liquid level reaches the level L2 (indicated by the uppermost dotted line position in the tank T in FIG. 4) the sperical float 24 will be constrained to assume the dotted line position shown in FIGS. 2 and 3. This causes the float 24 to direct an upward force against the foot 368 on the bell crank 36 forcing the said bell crank 36 to pivot about the point 38 and force the contact foot 36A down against the plunger 32 of the air valve 28. The resulting depression of the plunger 32 opens the normally closed air valve 28 and permits pressure from the supply header and supply 40 and supply 42 to flow into the inlet portion 30A of the pressure manifold 30 and through the valve 28, out through the outlet 30B of the header 30 and into the gas whistle 44 to thereby sound an audible alarm indicating that the liquid level L2 has been achieved within the tank T.

From the foregoing, it can now be readily seen that the present invention satisfies a long-felt need in the art to aid in precluding environmental pollution due to oil spills and the like.

We claim:

1. An audible alarm device for detecting and signalling the advent of an overflow condition in a fluid storage tank, comprising:

a source of dry nitrogen gas under pressure;

gas operated audible means external of said storage tank;

pneumatic valve means mounted internally of said storage tank including pneumatic pressure lines interconnecting opposite sides of said valve means with said source and said audible means, respectively; and

float means mounted internally of said storage tank, inter connected with said valve means, and responsive to a predetermined fluid level representing the advent of an overflow condition in said storage tank to actuate said valve means to transmit gas from said source through said pneumatic lines to said audible means.

2. The invention defined in claim 1, wherein said float means comprises:

a float in said tank;

a fluid pervious float cage containing said float and constraining same to a limited vertical displacement in response to varying fluid levels in said tank; and

linkage means extending from said float cage to said valve means for actuating said valve means; said float rising in said float cage and engaging said linkage means in response to said predetermined fluid level to constrain said linkage means to actuate said valve means and effect actuation of said audible means.

3. The invention defined in claim 2, wherein said valve means is normally closed and said linkage means comprises:

pivot means on said valve means;

an 0 rating plunger for said valve means; and a be I crank ever pivoted intermediate the ends thereof on said pivot means;

said bell crank lever having means for engaging said float on one end thereof and means engaging said operating plunger on the other end thereof.

4. An audible alarm system for a plurality of fluid storage tanks to indicate the advent of an overflow condition in each of said tanks, comprising:

a common source of dry nitrogen gas under pressure;

a supply header extending from said source to each of said tanks;

a float actuated pneumatic valve means in each of said tanks, each said valve being normally closed;

a gas operated audible means adjacent each of said tanks and external thereto;

first pneumatic lines extending from said header into each of said tanks, connecting said header to one side of a respective one of said pneumatic valves; and

second pneumatic lines extending from other side or a respective one of said pneumatic valves out of the corresponding one of said tanks, connecting said other side to a respective one of said audible means;

each said valve being actuated to open position in response to a predetermined fluid level representative of the advent of an overflow condition in a respective one of said tank to permit the flow of dry nitrogen gas therethrough from said header to said audible means through respective ones of said first and second pneumatic lines to effect an audible indication of said advent of an overflow condition.

5. The invention defined in claim 4, wherein each said float actuated pneumatic valve means comprises:

a mounting bracket affixed to an interior wall of said tank in which said valve is contained;

a vertically displaceable float;

a float cage on said mounting bracket having openwork sides, a substantially closed lower end and a constricted upper end, constraining said float to a limited vertical displacement within said cage in response to variation in the fluid level in said tank about said cage;

an in-line pneumatic valve on said mounting bracket adjacent said float cage; and

a valve actuating linkage extending from said valve over said constricted upper end of said float cage and engaging said float to actuate said valve to an open condition upon the occurrence of said predetermined fluid level.

6. The invention defined in claim 5, wherein said constricted upper end of said float cage comprises an integral extension of said mounting bracket in the form of an open housing for said in-line pneumatic valve and said actuating linkage, said housing being so dimensioned as to preclude the emergence of said float from the upper end of said float cage.

Claims (6)

1. An audible alarm device for detecting and signalling the advent of an overflow condition in a fluid storage tank, comprising: a source of dry nitrogen gas under pressure; gas operated audible means external of said storage tank; pneumatic valve means mounted internally of said storage tank including pneumatic pressure lines interconnecting opposite sides of said valve means with said source and said audible means, respectively; and float means mounted internally of said storage tank, interconnected with said valve means, and responsive to a predetermined fluid level representing the advent of an overflow condition in said storage tank to actuate said valve means to transmit gas from said source through said pneumatic lines to said audible means.

2. The invention defined in claim 1, wherein said float means comprises: a float in said tank; a fluid pervious float cage containing said float and constraining same to a limited vertical displacement in response to varying fluid levels in said tank; and linkage means extending from said float cage to said valve means for actuating said valve means; said float rising in said float cage and engaging said linkage means in response to said predetermined fluid level to constrain said linkage means to actuate said valve means and effect actuation of said audible means.

3. The invention defined in claim 2, wherein said valve means is normally closed and said linkage means comprises: pivot means on said valve means; an operating plunger for said valve means; and a bell crank lever pivoted intermediate the ends thereof on said pivot means; said bell crank lever having means for engaging said float on one end thereof and means engaging said operating plunger on the other end thereof.

4. An audible alarm system for a plurality of fluid storage tanks to indicate the advent of an overflow condition in each of said tanks, comprising: a common source of dry nitrogen gas under pressure; a supply header extending from said source to each of said tanks; a float actuated pneumatic valve means in each of said tanks, each said valve being normally closed; a gas operated audible means adjacent each of said tanks and external thereto; first pneumatic lines extending from said header into each of said tanks, connecting said header to one side of a respective one of said pneumatic valves; and second pneumatic lines extending from other side or a respective one of said pneumatic valves out of the corresponding one of said tanks, connecting said other side to a respective one of said audible means; each said valve being actuated to open position in response to a predetermined fluid level representative of the advent of an overflow condition in a respective one of said tank to permit the flow of dry nitrogen gas therethrough from said header to said audible means through respective ones of said first and second pneumatic lines to effect an audible indication of said advent of an overflow condition.

5. The invention defined in claim 4, wherein each said float actuated pneumatic valve means comprises: a mounting bracket affixed to an interior wall of said tank in which said valve is contained; a vertically displaceable float; a float cage on said mounting bracket having openwork sides, a substantially closed lower end and a constricted upper end, constraining said float to a limited vertical displacement within said cage in response to variation in the fluid level in said tank about said cage; an in-line pneumatic valve on said mounting bracket adjacent said float cage; and a valve actuating linkage extending from said valve over said constricted upper end of said float cage and engaging said float to actuate said valve to an open condition upon the occurrence of said predetermined fluid level.

6. The invention defined in claim 5, wherein said constrIcted upper end of said float cage comprises an integral extension of said mounting bracket in the form of an open housing for said in-line pneumatic valve and said actuating linkage, said housing being so dimensioned as to preclude the emergence of said float from the upper end of said float cage.

Images