Collection tank for sump pump under building floor

A collection tank for mounting in a bed of gravel particles under a floor of a building for collecting ground water from an area under the floor has a tank body including a lower tank portion and an upper tank portion. The lower tank portion defines a container for collected water with an open top. The upper tank portion has an outer wall upstanding from the open top of the lower tank portion, in which the outer wall is perforated with holes for passage of ground water into the tank body. Each of the holes extends radially through the outer wall of the upper tank portion at an upward slope so as to minimize entry of surrounding gravel particles into the tank body through the holes.

FIELD OF THE INVENTION

The present invention relates to collection tank placed under a floor of a building to collect water from an area under the floor and which is capable of receiving a sump pump to pump the collected water from the collection tank away from the building.

BACKGROUND

A common arrangement for a building is to provide a series of weeping tiles in the form of perforated drainage piping about the perimeter and below the floor of the building which collect groundwater and direct the groundwater into a sump pit. A typical sump pit comprises a collection tank mounted in the ground below the floor of the building in connection with the weeping tile to collect water from the perimeter and below the floor of the building into the collection tank. A sump pump is mounted in the collection tank for pumping collected water through a discharge hose to a discharge location away from the building. The collection tank is typically perforated to allow surrounding groundwater to enter into the collection tank. To ensure adequate drainage through the ground below the floor, the ground is typically first excavated and filled with an aggregate material such as gravel which receives the collection tank therein below the floor of the building such that water flows through the spaces between the gravel particles and into the perforations in the walls of the collection tank for subsequent collection and pumping by the sump pump. Commonly used gravel below the floor of a building includes a particle size which may be smaller than the perforated holes in the walls of the collection tank such that some of the gravel particles may also pass through the holes into the interior of the collection tank in a manner which may interfere with effective operation of the sump pump.

SUMMARY OF THE INVENTION

According to one aspect of the invention there is provided a collection tank for mounting under a floor of a building for collecting ground water from an area under the floor comprising:

a tank body including a lower tank portion and an upper tank portion;

the lower tank portion having a bottom wall and an outer wall upstanding from the bottom wall, the outer wall and the bottom wall of the lower tank portion defining a container for collected water with an open top;

the upper tank portion having a bottom edge connected to the lower tank portion at the open top and having an outer wall upstanding from the open top, the outer wall of the upper tank portion being perforated with holes arranged in an array extending around a full periphery of the outer wall of the upper tank portion for passage of ground water through the array of holes into the tank body;

the upper tank portion having an open bottom for communication of the ground water into the lower reservoir portion;

the lower tank portion being arranged to receive the pump so as to pump water from the lower tank portion at a position below the open top of the lower tank portion and below the holes in the upper tank portion;

each of the holes extending radially through the outer wall of the upper tank portion from an outer perimeter edge at an intersection of the hole with an outer surface of the outer wall at an exterior of the tank body to an inner perimeter edge at an intersection of the hole with an inner surface of the outer wall at an interior of the tank body; and

each of the holes having a lowermost portion of the inner perimeter edge of the hole being at a greater height from the bottom wall than a lowermost portion of the outer perimeter edge of the hole.

By arranging each hole so that the inner peripheral edge of the hole is elevated at the lowermost point thereof relative to the lowermost point of the outer peripheral edge of the hole, each hole is effectively inclined upwardly and inwardly from the exterior to the interior of the tank. This allows water to readily pass through the hole while preventing gravel particles from readily passing through the hole to minimize the collection of gravel particles within the collection tank.

Preferably each hole is arranged such that the lowermost portion of the inner perimeter edge of the hole is at a greater height from the bottom wall than an intersection of an angle of repose of a granular material extending from an uppermost edge of the outer perimeter edge of the hole with the inner surface of the outer wall.

Preferably the tank is used with granular material having an average particle size that is smaller than a diameter of the holes.

Preferably each hole has a hole diameter that is between ¼ inch and ⅜ inch.

Preferably the outer wall of the upper tank portion has a wall thickness that is 0.1 and 0.2 inches.

Preferably each hole extends radially inward from the outer surface of the outer wall to the inner surface of the outer wall at an upward inclination. The upward inclination may be at least 35 degrees from horizontal and more preferably is at least 45 degree from horizontal. In addition, the upward inclination may be less than 55 degrees from horizontal and more preferably is less than 50 degrees from horizontal.

DETAILED DESCRIPTION

Referring to the accompanying figures there is illustrated a collection tank generally indicated by reference numeral10. The collection tank is particularly suited for use below the floor12of a building. The collection tank is typically surrounded with a granular aggregate material14such as gravel that occupies a space below the floor of the building.

Although two embodiments of the collection tank are illustrated in the accompanying figures, the features in common with both embodiments will first be described herein.

In each instance the collection tank10comprises a tank body having a lower tank portion16forming the bottom of the tank10and an upper tank portion18forming the top of the collection tank. The lower tank portion has a hollow interior which is open at the top end thereof. The upper tank portion18includes a similar hollow interior, but is open at the bottom and so that the upper and lower tank portions openly communicate with one another and define a common hollow interior of the tank body.

The lower tank portion16includes a bottom wall20which is generally horizontally oriented in a mounted configuration and which is typically circular in shape for forming the lower boundary of the collection tank. The lower tank portion also includes an outer wall22which is upstanding from a perimeter of the bottom wall to fully surround the hollow interior of the lower tank portion. The outer wall22of the lower tank portion is generally cylindrical or frustoconical in shape so as to taper upwardly and inwardly from the bottom to the top according to the illustrated embodiment.

The upper tank portion18also includes an outer wall24which is generally cylindrical or frustoconical in shape between opposing top and bottom ends of the upper tank portion. The bottom edge of the outer wall24of the upper tank portion which defines the bottom end of the upper tank portion is connected to the open top end of the lower tank portion16in the assembled configuration of the tank body. The upper tank portion18also includes a top flange26in the form of an annular flange lying in a horizontal plane at the top end of the outer wall24of the upper tank portion to extend radially inward therefrom about a perimeter of a top opening28which occupies the majority of the top end of the upper tank portion.

A cover plate30the form of a round rigid plate is arranged to span the top end of the upper tank portion in overlapping arrangement with the top flange26about the full perimeter thereof for enclosing the top opening28of the tank body. Fastener apertures are provided at cooperating locations in the cover plate and the top flange to receive suitable fasteners for selectively and removably mounting the cover plate onto the top of the tank body.

A shoulder32extends radially inward from the top end of the lower tank portion to the bottom edge of the upper tank portion to span the radial distance between the larger outer diameter of the top end of the lower tank portion16relative to the smaller outer diameter of the bottom edge of the upper tank portion18connected thereto.

The bottom wall20of the lower tank portion is formed to include a raised platform34therein which serves as a suitable support for a sump pump36received thereon in a mounted position of the collection tank below the floor of a building. The sump pump36is inserted into the assembled tank body through the top opening28in the upper tank portion prior to mounting of the cover plate30onto the tank body. A discharge hose38is connected to the sump pump and communicates through a respective opening in the cover plate so that the sump pump is configured to pump water collected in the bottom of the collection tank10upwardly through the discharge hose38for discharging to a separate discharge location away from the building.

The tank body is typically perforated as described in further detail below such that groundwater surrounding the collection tank can weep through perforations in the collection tank for subsequent collection within the lower tank portion of the collection tank so that the collected water can be pumped away by the sump pump. The collection tank may also include one or more pipe openings40formed in the outer wall of the upper tank portion18to receive weeping tile or other suitable drainage pipe communicating therethrough for directing collected groundwater from other locations of the building into the interior of the collection tank10.

The lower tank portion is typically imperforate and devoid of any perforations or holes such that the outer wall22and the bottom wall22which are connected collectively define a suitable container or receptacle capable of containing and collecting water therein to be pumped away by the sump pump. The outer wall24of the upper tank portion is perforated by an array of drain holes42formed in the outer wall to substantially cover the entirety of the outer wall of the upper tank portion.

Each drain hole42comprises a cylindrical bore extending through the outer wall from an exterior surface44of the tank wall to an interior surface46of the tank wall at an upward and inward slope. More particularly the axis of the bore is inclined upwardly and inwardly at a preferred inclination of 45 degrees from horizontal or within a preferred range of 45 to 50 degrees from horizontal. An upward and inward inclination of the axis of each drain hole in the range of 35 to 55 degrees may also be effective.

Each drain hole includes an outer perimeter edge48located at the intersection of the bore through the outer wall with the exterior surface44and an inner perimeter edge50located at the intersection of the bore through the outer wall with the interior surface46. The outer wall typically has a radial thickness from the exterior surface44to the interior surface46thereof which is between 0.1 and 0.2 inches. The diameter of the bore forming each drain hole is typically between ¼ and ⅜ of an inch.

Overall each drain hole42is typically arranged so that the bottom52at the lowermost portion of the inner perimeter edge50is located above or at greater elevation than the bottom54at the lowermost portion of the outer perimeter edge48. The lower boundary surface of each drain hole is thus ramped upwardly and inwardly from the outer perimeter edge to the inner perimeter edge to discourage aggregate particles falling through the drain holes42from the exterior into the interior of the collection tank.

In a preferred arrangement, the bottom52of the inner perimeter edge50is near in elevation to the top56at the uppermost portion of the outer perimeter edge48. In the resulting arrangement, an angle of repose R of material deposited about the collection tank which extends from the top56of the outer perimeter edge of each hole intersects the interior surface46at a location X which is lower in elevation than the bottom52of the inner perimeter edge50to further ensure that aggregate material deposited about the exterior of the collection tank does not readily spill through the drainage holes even when the average particle size of the aggregate material is less than the bore diameter of each drain hole.

Turning now more particularly to the embodiment shown inFIGS. 1 through 4, in this instance the upper tank portion18and the lower tank portion16comprise a singular, unitary body of material. With the exception of the configuration of the drain holes, the tank body in this instance is substantially identical to the collection tank described in U.S. Pat. No. 5,727,901 by Rennie et al., the disclosure of which is incorporated herein by reference.

Turning now more particularly to the embodiment shown inFIG. 5, in this instance the upper tank portion18is readily separable from the lower tank portion16so that the collection tank is more readily collapsed for shipping and storage.

Turning now more particularly to the embodiment shown inFIGS. 6 and 7, in this instance the outer wall24of the upper tank portion18and the outer wall22of the lower tank portion16may each be corrugated. Accordingly, the outer wall24includes a plurality of first annular wall portions60extending at an upward and radially outward slope and a plurality of second annular wall portions62extending at an upward and radially inward slope. Each second annular wall portion62is located between a corresponding pair of the first annular wall portions60along a height of the upper tank portion. The holes42in the upper tank portion are located in the first annular wall portions60so as to be sloped upwardly and inwardly similarly to the previous embodiments.