Chopper pump with mixing nozzles for a sewage wet-well

Abstract

Systems and methods for conditioning sewage having entrained solids which clog sewage pumps, are disclosed. Systems include a sewage pump, a chopper pump, and a mixing nozzle connected to the chopper pump. Specifically, the sewage pump is a non-clog centrifugal pump having an inlet for drawing fluid into the pump and an outlet for discharging the fluid into a pipe, while the chopper pump has an inlet for drawing fluid into the pump and an outlet for discharging the fluid into the wet-well. The chopper pump may be positioned either in or adjacent to the wet-well. The mixing nozzle fluidly coupled to the chopper pump discharge, is positioned in the wet-well. Methods include the steps of positioning a chopper pump within the wet-well, drawing in liquid sewage, including the entrained solids, reducing the size of entrained solids, and discharging the sewage and reduced size solids into the wet-well.

Claims

1. A system for conditioning sewage in a sewage wet-well, the system comprising: a chopper pump having an inlet configured to draw sewage from a wet-well into a pump chopping zone where solids within the sewage are reduced in size to create a conditioned sewage, and an outlet configured to discharge the conditioned sewage back into the wet-well, the chopper pump being positioned either in or adjacent to the wet-well; at least one sewage pump positioned within the wet-well and having an inlet configured to draw the conditioned sewage into the pump and an outlet configured to discharge the conditioned sewage out of the wet-well; and at least one mixing nozzle fluidly coupled to the chopper pump discharge, wherein the mixing nozzle is positioned in the wet-well to create a mixing flow within the sewage as the conditioned sewage is discharged.

2. The system of claim 1, wherein the chopper pump is a submersible pump positioned within the wet-well.

3. The system of claim 1, wherein the chopper pump is a recirculating pump positioned within the wet-well.

4. The system of claim 3, wherein the mixing nozzle is attached to the recirculating pump.

5. The system of claim 1, wherein the mixing nozzle is directly attached to the chopper pump.

6. The system of claim 1, wherein the sewage pump comprises a non-clog centrifugal pump.

7. The system of claim 1, further comprising a discharge pipe connected to the sewage pump outlet, wherein the discharge pipe directs the sewage out of the wet-well.

8. A system for conditioning sewage, the system comprising: a sewage wet-well for collecting and storing sewage to be pumped to a sewage treatment facility, wherein the sewage is substantially liquid with solid material therein; a chopper pump having an inlet for drawing sewage from the wet-well into the pump, a chopping zone for reducing the size of the solid material to produce a conditioned sewage, and an outlet for discharging the conditioned sewage back into the wet-well, the chopper pump being positioned either in or adjacent to the wet-well; at least one sewage pump positioned within the sewage wet-well and having an inlet for drawing conditioned sewage into the pump and an outlet for discharging the conditioned sewage out of the wet-well; and a mixing nozzle fluidly coupled to the chopper pump discharge, wherein the mixing nozzle is positioned in the wet-well to create mixing of the sewage as the conditioned sewage is discharged.

9. The system of claim 8, wherein the chopper pump is a submersible pump positioned within the wet-well.

10. The system of claim 8, wherein the chopper pump is a recirculating pump positioned within the wet well.

11. The system of claim 10, wherein the mixing nozzle is directly attached to the recirculating pump.

12. The system of claim 8, wherein the mixing nozzle is directly attached to the chopper pump.

13. The system of claim 8, further comprising a plurality of mixing nozzles, wherein the nozzles are arranged within the wet-well to create a mixing flow within the sewage.

14. A method for reducing clogging of a sewage pump by solids entrained in substantially liquid sewage being collected in a sewage wet-well for pumping to a sewage treatment facility, the method comprising the steps of: positioning a chopper pump, having an inlet, an outlet, and a chopping zone, within a sewage wet-well to withdraw solid-entrained sewage from the sewage wet-well; drawing the solid-entrained sewage from the wet-well into the chopper pump via the inlet; reducing the size of entrained solids in the chopping zone of the chopper pump to create a conditioned sewage; and discharging the conditioned sewage back into the wet-well through a mixing nozzle coupled to the outlet of the chopper pump to thereby mix the sewage.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated.

(2) FIG. 1 is a side view of an embodiment of the present system in a sewage wet-well; and

(3) FIG. 2 is a top view of the embodiment of FIG. 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(4) While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to embodiments illustrated.

(5) With reference to the illustrations of FIGS. 1 and 2, an embodiment of a sewage conditioning system, generally referenced by the numeral 10, is shown and described below. The system 10 is used for reducing the size of solid debris entrained within the sewage, which is collected and stored in a wet-well, in order to facilitate pumping by larger flow (or sewage) pumps 20. Without such conditioning of the sewage, the larger pump(s) 20 may become clogged with the solid debris typically entrained in the sewage. By conditioning it is meant that the sewage, and particularly any solid debris within the sewage, is subjected to physical treatment to reduce the likelihood of clogging in sewage pump 20 and sewage discharge pipes 22.

(6) The need for the present system 10 in municipal wet wells occurs for at least one of two reasons: (1) municipalities are unable to replace existing sewage pumps; and (2) existing chopper pumps are unable to create the needed head or flow. As to the first reason, municipalities often operate on a tight budget and sufficient funds may not be available to invest in a brand new sewage pump system, or when a municipality does invest in expensive new sewage pumps, they may not work as reliably because of plugging problems. As to the second issue, even where a municipality might be willing and able to scrap out older sewage pumps that are constantly plugging, chopper pumps of the requisite flow capacity (i.e., generate the needed head or flow) or that are large enough to replace the original pumps, do not exist. Some municipality sewage pumps are much larger than chopper pumps currently available.

(7) In both scenarios the problem can be resolved by leaving in the current large sewage pump(s) 20 and adding at least one chopper pump 12 to condition the sewage by minimizing the size of solid material, thereby reducing if not eliminate the clogging problem. To do this, a submersible chopper pump 12 having a nozzle 14 affixed to the discharge is placed within a sewage lift station wet-well 30 to chop-up and mix-up debris so that the larger pumps 20 already installed in the station can handle this debris without plugging.

(8) Specifically, in these situations, at least one chopper pump 12, most preferably a submersible chopper pump, such as those designed, manufactured and sold by Vaughan Co., Inc. of Montesano, Wash. (http://www.chopperpumps.com), with a single nozzle 14 mounted on the pump discharge maybe strategically placed within the well 30. Alternatively, a self-priming or horizontal chopper pump, such as those designed, manufactured and sold by Vaughan Co., Inc., mounted outside the pit with one or two nozzles located in the pit may be used.

(9) In either case, the idea is to continuously mix up grit within the sewage liquid and chop up floating debris so that existing sewage pumps 20 will work reliably without plugging. The continuous chopping is provided by the use of at least one chopper pump 12. Exemplary chopper pumps and chopper pump features may be found in U.S. Pat. Nos. 8,118,244, 8,105,017, 7,841,550, 7,125,221, 5,460,483, 5,460,482, and 5,456,580, each of which is hereby incorporated by reference. The chopper pump 12 operates to reduce the size of solid debris, while continuous mixing is accomplished by the use of a mixing nozzle 14 attached to the chopper pump 12. Exemplary nozzles are described in U.S. Pat. No. 7,628,183 and U.S. Published Application No. 2011/0180633, both of which are hereby incorporated by reference.

(10) The nozzle 14 may be directed in a manner which is most efficient and effective at mixing the sewage to prevent settling of grit and other materials in the well 30. With reference to FIG. 2, the use of multiple nozzles 14 aimed to promote clockwise (or counter-clockwise) mixing of the sewage is preferred, especially in larger wells. As the pit collects grit, which tends to settle out of the liquid in the well 30, continuously mixing up the sewage helps to keep the grit entrained so that it is pumped out via the sewage pump 20. Without this mixing, the wet-well 30 would begin to fill up with grit which then requires the pit to be pumped and cleaned out on a regular basis by a vacuum truck. Pumping out the well 30 of settled grit is an expensive undertaking for a municipality. However, without removal of the grit, the well becomes overburdened and damage to the sewage pump 20 may result.

(11) The arrangement and number of chopper pumps 12 and mixing nozzles 14 may depend on the size and shape of the wet-well pit 30. Further, while the chopper pumps 12 and nozzles 14 are shown to be exclusively positioned on the pit bottom, it may be useful in some applications to have some or all nozzles 14 positioned significantly above the pit floor. Other alterations, changes and modifications may be made as to the arrangement and

(12) The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of applicants' contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.