Apparatus for trapping floating and non-floating particulate matter

A separation tank with an outer chamber and an inner chamber within the outer chamber. An inlet and outlet are formed in the outer chamber to receive and discharge water, respectively. An inlet opening is located in the inner chamber and is generally aligned with the inlet to receive water from the inlet. An outlet opening is formed in the inner chamber below the inlet opening but above the bottom of the inner chamber. The inner chamber has a cylindrical interior surface such that water from the inlet is directed at a tangent to the interior surface and forms a vortex as the water progresses through the inner chamber. A baffle plate having an opening forming upper and lower weirs is located within the outer chamber just upstream of the outlet to separate both floatable and non-floatable material from the water prior to its discharge.

TECHNICAL FIELD

The present invention relates generally to a device for trapping particulate matter in a liquid piping system. More specifically, the present invention relates to a device for trapping both floating and non-floating particulate matter flowing through a storm water sewer system.

BACKGROUND OF THE INVENTION

In the treatment of storm water, it is necessary to remove various undesirable elements and components, such as bacteria, oil, metals, nutrients, trash and a number of other solids. Many of the pollutants bond to the finer sediment and which is the reason many regulatory agencies now focus on total suspended solids (TSS) as a criteria for design/approval of stormwater quality measures.

To that end, the Clean Water Act requires some stormwater quality treatment for all new developments over 0.5 acres in size. Many types of equipment and processes have been suggested for dealing with this problem.

One of the difficulties in the removal of such materials from stormwater is the need to take into account different flows of that water. For example, under normal conditions, there may be a steady, relatively low flow of water that passes through the treatment facility, while at other times, there is a heavy storm and the flow rapidly turns into a high flow and, therefore, the stormwater treatment facility needs to also be able to handle that high flow of water to be treated.

The devices need to be capable of trapping both floating and non-floating debris under both flow conditions efficiently and at a low cost of the equipment.

One of the problems in dealing with both high and low flows is that the debris and other material may be effectively removed and settled in the particular stormwater equipment at the low flow conditions, however, when the flow is then elevated to a high flow condition, that high flow effectively scours out the previously settled material and then is carried downstream, thereby reducing or eliminating the effectiveness of the stormwater treatment device.

As a further problem in dealing with the differing flows, the high flow streams of water carry additional trash and larger solids that are only picked up and carried along by the higher flows and therefore there is a need to be able to capture that trash and larger solids with the stormwater treatment device.

Accordingly, there have been various stormwater treatment devices that provide for the separate treatment of the high flows and the low flows, and one typical manner of such treatment is to separate the high flow streams of water from the low flow streams in the water treatment device such that the high flows can be dealt with in a separate area that can effectively deal with those additional larger solids and trash while also preventing those high flow streams of water from scouring out the material that has been removed and therefore settled in the low flow treatment areas of the stormwater treatment device.

One of such stormwater treatment devices is shown and described in my co-pending U.S. patent application Ser. No. 10/247,875, filed Sep. 20, 2002, and entitled APPARATUS FOR TRAPPING FLOATING AND NON-FLOATING PARTICULATE MATTER and the disclosure of that patent application is hereby incorporated herein in its entirety by reference. In the stormwater treatment device of that patent application, however, the incoming stream of water to be treated enters an inner chamber in a direction that is perpendicular to the wall of the inner chamber and the water thereby directly hits the wall of the inner chamber where turbulence is created during both high and low flow conditions.

Additionally, the high and low flows are split in two directions but converge at the outlet where, again, turbulence occurs. Certainly, it would be preferable for the water treatment device to have the various streams of water pass smoothly through the treatment device and not be subjected to turbulence.

As a further difficulty with the stormwater treatment device of the aforesaid patent application, the device requires the installation of two sets of weirs, that is, two high and two low weirs in carrying out the treatment of the water flowing therethrough and those weirs must be installed in the field during the installation of the treatment device at the intended site. That use of two sets of weirs, however, along with the centralized location of the inner chamber, offers limited space within the overall water separation device by the use of the multiple weirs and is insufficient to allow a worker to enter the device to carry out that installation.

Thus, there is a desire for an efficient and cost effective means for trapping debris in storm water that overcomes the difficulties of the aforedescribed stormwater treatment devices and yet which is effective at trapping both floating and non-floating particulate matter. Such an apparatus should be simple in its design and be able to be produced at low cost. The device should be flexible in varying field conditions, i.e., able to satisfy varying size and height requirements and be able to connect efficiently to the non-linear junction points that inevitably occur in piping systems. Finally, such a device should be easy to maintain and not be prone to clogging or need the regular changing of filtering materials.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a stormwater separation tank that can remove floating and non-floating particulate matter from storm water in a cost effective and efficient manner. In the invention, the separation tank may include an outer chamber and an inner chamber positioned within the outer chamber. Preferably, the inner chamber is a generally cylindrical construction comprised of a cylindrical wall having an interior cylindrical surface. An inlet is provided in the outer chamber to receive the flow of water to be treated and an outlet is provided in the outer chamber to discharge that water after it has been treated in the stormwater separation tank.

An inlet opening is formed in the inner chamber and that inlet opening is located so as to be generally in vertical alignment with the inlet in the outer chamber such the flowing water that enters the inlet in the outer chamber can proceed into the inner chamber through the inlet opening in the inner chamber.

There is also an outlet opening formed in the inner chamber that is located vertically below the inlet opening in the inner chamber. The inlet opening and the outlet opening in the inner chamber are preferably rectangular openings.

The separation tank includes a baffle plate that is affixed to the interior surface of the outer chamber. The baffle plate has an opening formed therein that is preferably rectangular and which is located at a predetermined vertical location with respect to the separation tank and with respect to the inlet and outlet in the outer chamber and the inlet opening and outlet openings in the inner chamber. The baffle opening thus forms an upper weir and a lower weir for treatment of the water within the separation tank. The baffle plate is positioned within the outer chamber so as to isolate the outlet in that outer chamber such that all of the water that passes through the separation tank passes through the opening in the baffle plate to reach the outlet and thus, to be discharged from the separation tank.

The separation tank may further include a floor, and the inner chamber and the outer chamber may be positioned on the floor. The outer chamber may also be a cylinder having a cylindrical interior surface. The inlet, the inlet opening in the inner chamber and the outlet are positioned in a first vertical position range, and the outlet opening of the inner chamber is positioned in a second vertical position range, with the first vertical position range being higher than the second vertical position range.

The inner chamber is located in a particular position within the outer chamber such that it is not centered with respect to that outer chamber but is positioned off center and may have its wall touching or in close proximity to the interior surface of the inner wall of the outer chamber. That position allows the water flowing inwardly through the inlet of the outer chamber, due to its alignment with the inlet opening of the inner chamber, to pass from the inlet of the outer chamber into the inner chamber through the inlet opening in the inner chamber so as to strike the interior surface of the cylindrical shaped inner chamber at a tangent to that interior cylindrical surface thereby forming a vortex action where the water swirls in one direction around the interior surface of the inner chamber and turbulence is eliminated.

In addition, with the use of a single baffle plate that is located at or adjacent to the outlet in the outer chamber, as well as the offsetting of the inner chamber with respect to the center of the outer chamber, there is sufficient space within the separation tank so as to allow a person to enter the separation tank in order to affix the various components in their desired location therein.

These and other features of the present invention will become apparent upon review of the following detailed description of the present embodiments of the separation tank, when taken in conjunction with the drawings and the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

Referring now toFIGS. 1 and 2, there is shown a separation tank10constructed in accordance with the present invention. The separation tank10may be constructed of an outer chamber wall12and forms an outer chamber14and, likewise, there is an inner chamber wall16forming an inner chamber18. In both cases, the outer chamber and inner chamber walls12,16may be cylindrical walls and the outer chamber wall12and inner chamber wall16can be constructed of a pre-cast concrete, fiberglass, plastic steel or similar types of material, it not being essential to the invention as to the particular material.

An inlet20is formed in the outer chamber wall12that is adapted to receive the flowing water to be treated. As will be seen the vertical location of the inlet20on the outer chamber wall12is significant and is a predetermined vertical location. The inlet20may be constructed with any piping materials commonly known in the art, e.g., concrete, aluminum, steel, PVC, HDPE, or other like materials and can be sealed to the outer chamber wall12by methods commonly known in the art, including the use of rubber boots, concrete grout, or similar types of materials or methods. Preferably the inlet20is a pipe or a similar structure with a diameter in the range of about 12 to 60 inches, although the particular sizing is not essential.

An outlet22is also formed in the outer chamber wall12and which is adapted to discharge the water from the separation tank10after that water has been treated and, again, the vertical position of the outlet22on the separation tank10is of importance to the present invention. Preferably, the outlet22is a pipe with a diameter in the range of about 12 to 60 inches, although the particular sizing is not essential, however, the outlet22generally may be the same size or larger than the inlet20. The outlet22may make a watertight connection with the outer chamber wall12as the outlet22exits the separation tank10. As described above, rubber boots, concrete grout, or similar types of materials or methods can be used to seal the outlet22to the outer chamber wall12.

In the present embodiment of separation tank10, the outer chamber14may have a volume in the range of about 100 to 1800 cubic feet with an overall diameter of about 4 to 12 feet and a height of about 8 to 16 feet. The dimensions of the inner chamber18are smaller than that of the outer chamber14such that the inner chamber18may fit inside of the outer chamber14as is shown inFIGS. 1 and 2. Preferably the inner chamber18may have a volume in the range of about 40 to 800 cubic feet with an overall diameter of about 3 to 8 feet and a height of about 8 to 12 feet.

With the inner chamber18and outer chamber14having similar shapes in the present embodiment, that is, cylindrical, as discussed above, the center C of the inner chamber18can be seen, particularly inFIG. 2, to be displaced away, that is, radially outwardly, from the center D of the outer chamber14. Accordingly the inner chamber wall16can actual touch the interior surface24of the outer chamber wall12or at least be in close proximity thereto.

The position of the inner chamber18is predetermined with respect to the location of the inlet20and includes an inlet opening26that is formed in the inner chamber wall16at a predetermined vertical height in that inner chamber wall16.

There is also an outlet opening28formed in the inner chamber wall16and which is located vertically lower with respect to that inlet opening26. Both the inlet opening26and the outlet opening28can be rectangular in shape with a major horizontal longitudinal axis.

A baffle plate30is located within the separation tank10and, as shown, the baffle plate30is an arcuate plate that extends from one point along the interior surface24of the outer chamber wall12to another point along that interior surface and effectively creates an intermediate chamber32within the separation tank10and within the outer chamber14between the inner chamber wall16and the baffle plate30. A further chamber, that is, an outlet chamber34is formed between the baffle plate30and an area within the interior surface24of the outer chamber wall12and which outlet chamber leads into the outlet22. As such, the outer chamber14is subdivided, for purposes of the present description into subchambers comprising intermediate chamber32and outlet chamber34.

There is a baffle opening36formed in the baffle plate30and is preferably a rectangular configuration such that there is an upper edge creating an upper weir38and a lower edge creating a lower weir40. Again, the vertical location of the baffle opening36is a predetermined position with respect to the separation tank10as well as to the inlet20and the inlet and outlet openings26,28and outlet22.

Both the inner chamber wall16and the outer chamber wall12may rest on a floor42. The floor42may be a circular piece of rigid material, e.g., precast concrete, poured in place concrete, or similar types of materials. The selection of the materials is not essential. The floor42may make watertight connections with both the outer chamber wall12and the inner chamber wall16per methods common in the art. As described above, rubber gaskets, neoprene gaskets, nitrile gaskets, or similar types of materials or methods may be used. The floor42may be sized such that its diameter is about the same as the diameter of the cylinder formed by the outer chamber wall12.

The top of the outer chamber wall12may be left open or bound by a cover46. The cover46can include a circular piece of a rigid material, i.e., precast concrete, stainless steel, aluminum, or other similar material. The selection of the material is not essential. The diameter of the cover46is preferably the same as the outer chamber14such that a substantially tight seal may be formed between the cover46and the outer chamber wall12. The cover46may include a single or multiple access openings (not shown) in order to allow the entry of a person to initially assemble and install the separation tank10and to carry out maintenance procedures, including the removal of debris that will settle in the bottom of the separation tank10from time to time.

Turning now toFIG. 3, there is shown a side view of the inner chamber wall16that creates the inner chamber18. As can be seen, the inlet20, shown in phantom, is basically horizontally aligned with the inlet opening26such the water entering the separation tank10(FIG. 1) through the inlet20will continue flowing naturally so as to enter the inner chamber18through the inlet opening26. As can be seen, the vertical position of the inlet opening26is about two thirds of the total height of the inlet chamber18off of the lower edge44of the inner chamber wall16, however, the actual location and size of the inlet opening26may vary widely depending on the location and size of the inlet20and outlet22.

The outlet opening28is also shown to be about one third of the height of the inlet chamber wall upwardly from the lower edge44of the inner chamber wall16however, again, the actual location of outlet opening28may vary depending on the inlet20and the outlet22as long as the outlet opening28is located below the inlet opening26but above the lower edge44of the inner chamber wall16.

Turning finally toFIG. 4, there is shown a front view of the baffle plate30of the present invention and illustrating the baffle opening36that creates the upper weir38and the lower weir40. As also can be seen, the vertical location of the baffle opening36is at or slightly lower than the mid point of the vertical height of the baffle plate30and is located vertically higher than the outlet opening28but lower that the inlet opening26and lower than the vertical location of the outlet22(FIGS. 1 and 2), however, the width and vertical position of the baffle opening36can vary while still being within the spirit and intent of the present invention.

Accordingly, the operation of the separation tank10can now be described. The flow of the water to be treated enters the separation tank10by means of the inlet20and, at normal, or low flows, the water passes through inlet20whereupon it enters the inner chamber18through the inlet opening26. As such, the water hits the interior surface48of the inner chamber wall16along a tangent to the cylindrical configuration such that the water flows in a vortex smoothly around the interior surface48of the inner chamber wall16where it gradually moves downwardly by gravity until it passes out of the inner chamber18through the outlet opening28and enters the intermediate chamber32.

During its passage around the inner chamber18, the solids drop to the bottom of the inner chamber18to be collected therein and, since the outlet opening28is located a predetermined vertical distance above the bottom of the inner chamber, those solids and non-floating particulate matter remain and collect in the bottom of the inner chamber18where those solids can be periodically cleaned out in the course of normal maintenance.

The water passing out of the outlet opening28then passes through the intermediate chamber32and thereafter passes though the baffle opening36into the outlet chamber34and then is discharged out of the separation tank10through the outlet22. When the treated water passes through the baffle opening36, however, floating materials such as oil are prevented from passing through the baffle opening36by means of the upper weir38that blocks the floating material from passing through the baffle opening36since the level of the water in the separation tank10is designed to be higher than the level of the upper weir38and the baffle opening36is designed to be lower than the outlet22. Likewise, the non floating particulate material heavier solids are prevent by the lower weir40from passing through the baffle opening36and therefore are also effectively prevented from being discharged through the outlet22. Non-floating particulate matter of any size may be filtered in this manner.

In the event of a high flow during a heavy storm, the high flow of water does not enter the inner chamber18since that additional flow is too much flow to enter the relatively restricted inlet opening26in the inner chamber18and thus the high flow is diverted away from the inner chamber18and flows instead directly into the intermediate chamber32generally at a tangent to the interior surface of the outer chamber wall12where it thereafter proceeds directly to the baffle opening36in the baffle plate30.

Thus, the high flow, since it does not enter the inner chamber18, does not stir up or purge the solids or non-floatable material that have collected at the bottom of the inner chamber18. On the other hand, since that high flow must pass through the baffle opening36and therefore, under the upper weir38and over the lower weir40, that water still has the floatable and non-floatable materials removed from the high flow stream of water by the time that stream is discharged through the outlet22.

As can therefore, be seen, any floating particulate matter in the storm water can be trapped within the separation tank10. Upon entering the separation tank10, floating particulate matter is directed into the inner chamber18or during high flow the outer chamber14, as discussed above, and remains in the inner chamber18or the outer chamber14. In the inner chamber18, i.e. at low flows, the floating particulate matter remains near the surface of the water and is unable to exit the inner chamber18because outlet opening28is positioned at, or near, the bottom of the inner chamber18. At high flows, any floating particulate matter in the outer chamber14is blocked from the outlet22by the upper weir38.

On the other hand, any non-floating particulate matter that enters the separation tank10during the periods of low flow is trapped at the bottom of the inner chamber18since it cannot leave the inner chamber18due to the location of the outlet opening28that is spaced above the bottom of that inner chamber18while, at high flows the non-floating particulate matter is trapped at the floor42of the intermediate chamber32since it is unable to pass through the baffle opening36in the baffle plate30such that the non-floating particular matter is trapped in the separation tank10at both the high and low flows.

Any obstruction in the inner chamber18or in the inlet opening26will not prohibit water flow through the separation tank10since the water will flow directly into the outer chamber14and flow under the upper weir38and over the lower weir40.

The inlet20and the outlet22may be positioned at the same or a similar height from the floor42of about 4 to 8 feet, although this measurement may increase or decrease depending on the size and usage of the separation tank10as a whole. Preferably, the inlet20may be 1–3 inches higher than the outlet22.

Those skilled in the art will readily recognize numerous adaptations and modifications which can be made to the water separation tank of the present invention which will result in an improved water treatment system, yet all of which will fall within the scope and spirit of the present invention as defined in the following claims. Accordingly, the invention is to be limited only by the following claims and their equivalents.