Automatic overfill prevention system

• US 4,770,317 A
• Filed: 05/15/1987
• Issued: 09/13/1988
• Est. Priority Date: 05/15/1987
• Status: Expired due to Fees

• Current Assignee: EMCO Wheaton Retail Corporation
• Original Assignee: Emco Wheaton, Inc.
• Inventors: Podgers, Alexander R., Butterfield, Eric J.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/049,972
• Time in Patent Office: 487 Days
• Field of Search: 137/234.6, 137/386, 137/389, 137/390, 137/393, 137/599.2, 141/1, 141/86, 141/209, 220/86 R
• US Class Current: 220/86.1
• CPC Class Codes: B67D 7/362 combined with over-fill preventing means indicating or measuring liquid level G01F23/00; level control G05D9/00

Abstract

An automatic overfill prevention system for gravity filling of an underground liquid storage tank from a tank truck fill line provides a venturi in the fill line creating a partial vacuum which is vented from the liquid storage tank through a vent line until the liquid in the storage tank rises to a predetermined level to submerge one end of the vent line and trigger a latching means to close the fill line. The assembly also includes a containment manhole to hold any inadvertent spillage occurring during the filling process.

Claims

1. An assembly for gravity filling an underground storage tank from a tank truck fill line, which comprises:

a manhole rim adapted to be located at ground level;

a cylindrical manhole housing located below the rim;

an elastomeric expansion sleeve connecting the rim to the housing;

a body having a liquid fill passage within the housing and below ground level for the passage of liquid under the influence of gravity, the fill passage having a narrowing venturi throat portion, the fill passage adapted to be connected at one end to the fill line from the tank truck and adapted to be rigidly connected at the other end to the liquid storage tank, the body also having a portion forming a manhole bottom rigidly attached to the bottom of the housing;

a drain passage integrally formed in the manhole bottom allowing liquid to drain from the bottom of the manhole into the fill passage;

a drain valve closing the drain passage and capable of being opened to drain liquid in the manhole bottom into the fill passage;

valve means in the fill passage movable between an open position in which the fill passage is open to permit the flow of liquid through the passage and a closed position in which the fill passage is closed to interrupt the flow of liquid to the storage tank;

means for urging the valve means to the closed position;

pressure-responsive latch means for engaging the valve means and releasably locking the valve means in the open position;

a vent passage having one end adapted to open in the storage tank at a predetermined level below the upper end of the tank and the other end communicating with the pressure-responsive latch means; and

a vacuum passage communicating between the pressure-reponsive latch means and the narrowing venturi throat position of the fill passage, the flow of liquid through the fill passage causing a partial vacuum to be formed at the narrowing throat portion, the partial vacuum being vented through the vacuum passage and the vent passage when the level of liquid in the liquid storage tank is below the level at which the end of the vent passage opens, the partial vacuum causing the pressure-responsive latch means to release the valve means when the level of liquid in the liquid storage tank rises to close the end of the vent passage, the release of the pressure-responsive latch means causing the valve means to move to the closed position by the urging means.

2. An assembly for gravity filling an underground liquid storage tank as defined in claim 1, wherein the liquid fill passage includes a valve seat which is sealingly engaged by the valve means when the valve means is in the closed position, and the narrowing venturi throat portion is formed at the valve seat.

3. An assembly for gravity filling a liquid storage tank as defined in claim 1, wherein the valve means includes a pressure-responsive relief poppet portion which opens when the pressure of the liquid flow in the fill passage exceeds a predetermined level during the closing the valve.

4. An assembly for gravity filling a liquid storage tank as defined in claim 1, comprising in addition means for testing the pressure-responsive latch means comprising means for manually closing the vent passage.

5. An assembly for gravity filling a liquid storage tank as defined in claim 1, comprising in addition means for manually opening the valve means.

6. An assembly for gravity filling a liquid storage tank as defined in claim 1, comprising in addition an outer housing extending down from the rim outside the manhole housing, the expansion sleeve located in between the manhole housing and the outer housing.

7. An assembly for filling a liquid storage tank as defined in claim 1, wherein the expansion sleeve is accordion-folded to permit substantial vertical movement of the body with respect to the rim.

8. An assembly for gravity filling an underground storage tank as defined in claim 1, comprising in addition a lid supported on the rim.

9. An assembly for gravity filling an underground liquid storage tank from a tank truck fill line, which comprises:

a manhole rim adapted to be located at ground level;

a lid supported on the rim;

an outer manhole housing extending down from the rim;

a cylindrical inner manhole housing located below the rim and spaced inside the outer housing;

an elastomeric expansion sleeve connecting the rim to the inner housing, the expansion sleeve located in the space between the outer housing and the inner housing, the expansion sleeve being accordion-folded to permit substantial vertical movement of the inner housing relative to the rim;

a body having a liquid fill passage within the inner housing and below ground level for the passage of liquid under the influence of gravity, the fill passage including a valve seat, the fill passage having a narrowing venturi throat portion formed at the valve seat, the fill passage adapted to be connected at one end to the fill line from the tank truck and adapted to be rigidly connected at the other end of the liquid storage tank, the body also having a portion forming a manhole bottom rigidly attached to the bottom of the housing;

a drain passage integrally formed in the manhole bottom allowing liquid to drain from the bottom of the manhole into the fill passage;

a drain valve closing the drain passage and capable of being opened to drain liquid in the manhole bottom into the fill passage;

valve means in the fill passage movable between an open position in which the fill passage is open to permit the flow of liquid through the passage and a closed position in which the valve means sealingly engages the valve seat to close the fill passage and interrupt the flow of liquid to the storage tank, the valve means including a pressure-responsive relief poppet portion which opens when the pressure of liquid flow in the fill passage exceeds a predetermined level during the closing of the valve;

means for urging the valve means to the closed position;

means for manually opening the valve means;

pressure-responsive latch means for engaging the valve means and releasably locking the valve means in the open position;

a vent passage having one end adapted to be open in the storage tank at a predetermined level below the upper end of the tank and the other end communicating with the pressure-responsive latch means;

a vacuum passage communicating between the pressure-responsive latch means and the narrowing venturi throat portion of the fill passage, the flow of liquid through the fill passage causing a partial vacuum to be formed at the narrowing throat portion, the partial vacuum being vented through the vacuum passage and through the vent passage when the level of liquid in the liquid storage tank is below the level at which the end of the vent passage opens, the partial vacuum causing the pressure-responsive latch means to release the valve means when the level of liquid in the liquid storage tank rises to close the end of the vent passage, the release of the pressure-responsive latch means causing the valve means to move to the closed position by the urging means; and

means for testing the pressure-responsive latch means comprising means for manually closing the vent passage.