Sewage system agitator

A sewage system component spray assembly is attached at a predetermined height above pumps in the interior of the component and has at least one nozzle for spraying liquid downwardly and generally tangential to a center of the sewage system component. Operation of the nozzle causes the liquid to disperse floating material on the sewage surface and creating a rotational flow around the center to direct such material to the pumps.

TECHNICAL FIELD

The present disclosure relates to an agitator for a sewage system component such as a pumping station.

BACKGROUND

Sewage systems remove waste via flow of water and other entrained material through pipes to sewage treatment plants. Generally, the flow is moved in a desired direction by arranging the pipes so that gravity draws the flow “downhill.” At times assistance is provided by sewage pumps, for example, to urge flow along and/or to lift flow to a higher level where gravity based flow starts again. Such pumps may be located in a structure along the sewer line in structures commonly known as a wet well, a lift station, or a pumping station.

Such pumps are electrically operated and are often automatically turned on and off by sensors such as float switches, proximity switches, probes, or the like. For example, when a sensor notes that material in a pumping station has reached a first predetermined (full) level, the pumps operate to pump out the material. During pumping, when another sensor notes that material has fallen to a second predetermined (empty) level, the pumps cease operation. Even at an “empty” level in the pumping station, some material remains as the pump inlets are arranged so as to remain under the surface of the liquid to prevent malfunction. This operation continues and the pumping station is sequentially filled by flow and then pumped out by the pumps.

Sewage contains various substances, such as waste, fats, greases, grit, and slime, etc. Some of such substances will float on top of the liquid in the pumping stations and therefore not reach the pump inlets. The substances can build up over time requiring chemical treatment and/or regular mechanized or manual removal. Such substances can also form hardened conglomerations over time. Such masses may eventually block pump inlets, or may be drawn through the inlets into the pumps, thereby causing clogging or damage. Fats and greases, for example, are known to float and collect into large somewhat solid clumps that can be problematic in this way.

Accordingly, improvements in pumping stations that provide more reliable and/or less labor-intensive operation addressing one or more drawbacks of current systems or other issues would be welcome.

SUMMARY

According to certain aspects of the disclosure, a sewage system component may include a container for receiving a flow of sewage, the container defining a central axis; at least one pump in the container for pumping sewage out of the container, the pump operational to pump sewage when the sewage is at a first height until the sewage is at a second height lower than the first height; and a spray device mounted in the container at a predetermined height between the first height and the second height. The spray device is connected to a source of liquid, the spray device having a nozzle directed downward and generally tangential to a circle around the central axis. Operation of the spray device disperses floating material on the sewage surface and creating a rotational flow around the central axis to assist the pump in removing such material when the pump pumps the sewage. Various options and modifications are possible.

According to certain other aspects of the disclosure, a spray assembly is disclosed for an interior of a sewage system component having a pump therein. The assembly may include a mount for attachment at a predetermined height above the pump in the interior of the sewage pumping station; a connector attached to the mount for attachment to a source of liquid; a conduit extending from the connector for carrying the liquid; and a nozzle connected to the conduit for spraying liquid downwardly and generally tangential to a center of the sewage pumping station. Operation of the nozzle causes the liquid to disperse floating material on the sewage surface and creating a rotational flow around the center to direct such material to the pump. Various options and modifications are possible.

According to another aspect of the disclosure, a method of emptying a sewage system component may include the steps of sensing that the component is filled to a first level; pumping sewage from the component after the sensing step; sensing when, during the pumping step, the sewage level has dropped to a predetermined level lower than the first level; spraying, during the pumping step and after the sensing of the predetermined level, with a nozzle located above the predetermined level downwardly and circumferentially within the component with enough force to disperse floating matter and cause rotation within the component; and continuing to pump sewage from the component while continuing to spray until the sewage level has dropped to a second level lower than the predetermined level. Various options and modifications are possible.

DETAILED DESCRIPTION

Detailed reference will now be made to the drawings in which examples embodying the present disclosure are shown. The detailed description uses numeral and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the disclosure.

The drawings and detailed description provide a full and enabling description of the disclosure and the manner and process of making and using it. Each embodiment is provided by way of explanation of the subject matter not limitation thereof. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the disclosed subject matter without departing from the scope or spirit of the disclosure. For instance, features illustrated or described as part of one embodiment may be used with another embodiment to yield a still further embodiment.

Generally speaking,FIGS. 1-9depict an example of a sewage system component such as a pumping station10including a container12for receiving a flow of sewage, at least one pump14for pumping sewage out of the container, and a spray device (agitator spray head)16mounted in the container for spraying the sewage at a predetermined time.

Component/container12can be any type of sewage carrying or water treatment tank, container, etc. Thus, container12can be any type of container located along a sewer line, such as those commonly called a wet well, a pumping station, a lift station, a vault, etc. At times such terms are often used inconsistently or interchangeably in the field. Typically, containers are formed of concrete, and are circular in cross-section, sometimes cylindrical and sometimes varying in diameter along their height. Container12is illustrated herein as a cylinder. Container12may also be a tank, lagoon, or holding pond in a water treatment facility. However, no limitation should be made as to the type, shape, construction material, etc., of such container. Further, although a central axis18of container12is discussed herein, such does not require that container12is cylindrical or circular in cross section. Central axis18merely refers to a generally middle point of container12, extending upwardly.

The present disclosure shows two of the pumps14, which is conventional in pumping stations. One skilled in the art can readily select one or more suitable pumps14for station10from commercially-available sources, in view of the size, head, desired flow rate, expected contents of the flow, duty cycle, etc. Pumps14are positioned in container12on conventional vertical guide rails20. Pumps14may be slidable along guide rails20or fixed to guide rails20as desired, for placement and removal within container12. As illustrated, each pump14is mounted along two of the guide rails20, although other numbers of guide rails, or no guide rails, could be used.

Pumps14periodically pump sewage out of container12out of common outlet22after the container fills via inlet24. Outlet22as illustrated is higher within container12than inlet24, although it need not be.

Pumps14pump sewage when the sewage is at a first height until the sewage is at a second height lower than the first height First height is any desired height within container at which pumping is desired. First height may be the height of sensor26, which is illustrated as below the height of inlet24but need not be. Second height may be the height of sensor28, which is illustrated at or near the bottom of container12but need not be. Sensors26and28may be any suitable type of sensor such as float switches, reverse float switches, liquid sensors, visual sensors, etc. Pumps14and sensors26and28are connected to a conventional pump controller30. Additional sensors (not shown) may also be provided at different locations or heights and connected to controller30to obtain more information and/or fine tune operation of the pumping station, as is conventionally known.

Accordingly, during typical operation of pumping station10, sewage flows into inlet24until the level reaches first height and is sensed by sensor26. When sensor26notes sewage has reached that level, it signals controller30, which in turn signals pumps14to operate until sensor28detects that the level of sewage has fallen to the second height. Sensor28signals such to controller30, which then turns off pumps14. This filling and emptying cycle repeats as needed.

Strictly speaking, sensors26and28are not required for all aspects of the present invention, but are explained here to show one typical installation of a spray device16within a container. Thus, pumps14can be operated on other bases (i.e., other sensors, timers, etc.) within the scope of the invention.

Spray device16is mounted in container12at a predetermined height between the first height (e.g., the height of sensor26) and the second height (e.g., the height of sensor28). The predetermined height may be between 6 to 12 inches above pumps14, for example. Spray device16is connected to a source of liquid32. The liquid may be a source of mains water, a dedicated water tank, and/or water treated with chemicals for any purpose used in sewage systems.

Spray device16has at least one nozzle34directed generally downward and/or at least partially tangential to a circle around central axis18of container12(seeFIGS. 5 and 7-9). As illustrated, spray device16includes two such nozzles34, each mounted to an end of a conduit36extending substantially horizontally with an axis38extending therealong. If desired, nozzles34may be rotational relative to axis38to fine tune the angle of spray relative to the sewage to suit a particular installation. Such rotational function may be provided by threading or a rotational seal existing between nozzles34and conduit36, or between conduit36and cross-piece46.

Spray device16sprays generally downward and slightly rotationally relative to axis18once the level of the sewage has dropped to a level slightly below the spray device (seeFIG. 3). Using two nozzles34spraying circumferentially the same rotational direction (clockwise or counterclockwise) assists in creating fluid rotation within container12. Such spray disperses floating material on the sewage surface and creates a rotational flow around the central axis18to assist pumps14in removing such material when pumping. The rotation of liquid assists in getting more floating material to pass nozzles and be sprayed and dispersed, as compared to using two fixed spray nozzles pointing only straight down. Such spraying continues until either the pumps stop due to sensor28and/or a spray stop level is reached.

Using a fixed spray device16with circumferentially angled spraying, rather than a rotational spray device with straight down spraying, provides a simplified and more reliable structure. This is particularly true because the spray device is most efficient and effective if located vertically relatively near the pumps toward the bottom of container12. Such location is therefore often covered with sewage before pumping occurs, and a rotational mechanism at such location might become damaged, degraded, or impeded by spending time submerged in the sewage. Also, more force is transmitted by the pressurized sprayed water to the sewage by using a fixed but angled sprayer, as opposed to using a rotational sprayer, in which some of the water pressure force is used to create rotation of a spray head.

As illustrated, a spray controller40is provided along with sensors42and44to control starting (sensor42) and stopping (sensor44) of spray device16. It should be understood that controllers30and40could be a single controller, or could be separate controllers housed in a single housing. Controllers30and40if separate can be operated jointly or separately, and sensors26,28,42and44can be tied together into one system or two. Also, an individual sensors can be used for both the pumping system/controller and the spraying system/controller. Also, sensors28and44, for example, could comprise the same sensor. Therefore, many modifications of the sensing and control functions of both the pumping and spraying systems are possible. Using a separate sprayer controller40and sensors42and44, although not necessary in all aspects, provides the benefits of ease of retrofitting existing systems and certain optional choices during installation.

If desired, each nozzle34may include a first outlet48and a second outlet50to provide more spray coverage into the sewage container12. As illustrated, first outlet48may be oriented up to about 10 degrees from the vertical in circumferential and radially inward directions relative to the central axis, and the second outlet50may be oriented up to about 35 degrees from the vertical in circumferential and radially inward directions. Using multiple outlets assists in dispersing more materials to pumps14. Also, having an outlet such as50pointing a bit more circumferentially helps create rotation within container12, thereby causing the sewage to rotate within container and bringing more of the sewage beneath one of the outlets to further disperse the floating materials.

It should be understood that the nozzle examples above are only one example of possible nozzle locations and angles. For example, one nozzle could point downward parallel to central axis, and one could be angled circumferentially. One, both, or neither nozzle may be angled radially. Each nozzle may include only one outlet. Only one nozzle may be provided, with one, two or more outlets. Further outlets may be provided by other nozzles and/or outlets along the conduit. Center of spray of outlet48thus may be angled from 0 to about 20 degrees, radially and/or circumferentially (see angle a inFIG. 7-9). Center of spray of outlet50may be angled from about 15 to about 40 degrees, radially and/or circumferentially (see angle b inFIGS. 7-9). Also, radial angling may be inward or outward depending on the size of the spray device (in particular the length of conduit36) and the relative size of container12. Thus, depending on the particular application, many variations in the number and spacing of the nozzles, outlets, etc. are possible.

Spray device16may be mounted to guide rails20by adjustable mounts52. As illustrated, mounts52are located on a rod54connected to cross piece46. Therefore, spray device16has a rough H-shape. Such shape is provided in view of the fact that guide rails20are usually toward the side of a container12, and it is desired to move the spray nozzles34toward the center. It should be understood that other overall shapes for spray device16are possible.

Mounts52may be slidable along rod54and fixed in place, for example by a set screw, clamp or the like, so as to grip guide rods20and thereby hold spray device16at a desired height within container12. Further structure, such as a set screw, clamp or the like may be used to each mount52to a respective guide rods20, if desired. Alternatively, a simple frictional squeeze can be used to hold spray device16to guide rods20, once the width of mounts52is set along rod54. It should be understood that other mounting structures can be used, and spray device need not be mounted to guide rods.

A control valve assembly60is located between source of liquid32and spray device16, and is in communication with the spray controller40. The controller40causes control valve assembly60to open and close allowing liquid to flow to spray device16and out nozzles based on inputs from sensors42and44(and possibly26and28) within container12. As illustrated, control valve assembly60includes a one-way (back-flow prevention) valve62, a solenoid valve64, a pressure control valve66, and one or more shut-off valves68mounted in an s-shaped path within a frame70. Inlet72is connected to source of liquid32and outlet74is connected to a connector78on spray device16by a conduit76, such a as a hose or pipe. The flow order of the valves in assembly60may be altered from that shown. Solenoid valve64is usually in a closed condition unless opened by controller40because sensor42signals that liquid has fallen to that level within container12. Pressure control valve66is adjustable to achieve a desired flow and therefore spray intensity in view of the mains pressure and particular application. Control valve assembly60can be deployed as a unit in both new installations and retrofits.

The disclosed structures can be used to carry out many methods of agitating floating matter on sewage within a sewage system component, such as a pumping station. One such method includes sensing that the pumping station10is filled to a first level26; pumping sewage from the pumping station after the sensing step; sensing when, during the pumping step, the sewage level has dropped to a predetermined level42lower than the first level26; spraying, during the pumping step and after the sensing of the predetermined level, with a nozzle34located above the predetermined level downwardly and circumferentially within the pumping station with enough force to disperse floating matter and cause rotation within the pumping station; and continuing to pump sewage from the pumping station while continuing to spray until the sewage level has dropped to a second level28,44lower than the predetermined level.

As an example, in a system with mains pressure at around 60 psi, a spray device may run for about 6 seconds at a flow rate of 5 gallons per minute as the sewage level passes from the predetermined level to the second level. This is with the spray device about 12 inches above the pumps and spraying for about the final 6 inches worth of drainage from container12. Of course these parameters can readily be adjusted depending on type of container, type of waste flow experienced, water pressure, number of nozzles and outlets, size and type of nozzle outlet, etc. Controller40may cause spray device16to operate each time container12is emptied or only sometimes (either by keeping a count, or by relying on a timer or sensor to detect buildup of floating material, clogs or flow rates through pumps, etc.). Thus, many modes of operation are possible, and controller40and/or controller30may direct the system to operate according to one or more stored routines.

It should be understood that in such method and using such structure all floating material will not be dispersed and pumped out each cycle. However, sufficient materials will be pumped out that manual or chemical cleaning can be substantially reduced or eliminated. A new equipment installation or retrofit installation is possible. The cost of the spray device16, controller40, sensors42and44, control valve assembly60, etc., can be rapidly recouped by virtue of the improved performance and reduced cost of operation of the resulting pumping station system including subject matter disclosed herein.

While preferred embodiments of the invention have been described above, it is to be understood that any and all equivalent realizations of the present invention are included within the scope and spirit thereof. Thus, the embodiments depicted are presented by way of example only and are not intended as limitations upon the present invention. Thus, while particular embodiments of the invention have been described and shown, it will be understood by those of ordinary skill in this art that the present invention is not limited thereto since many modifications can be made. Therefore, it is contemplated that any and all such embodiments are included in the present invention as may fall within the literal or equivalent scope of the appended claims.