Patent Grant
9566622
The present invention relates generally to water quality management, and more specifically to vacuum break devices useful for flushing systems and flushing systems equipped with such novel vacuum break devices, as well as methods for sewer system cleaning, in particular, efficient flushing and cleaning of solid sediments accumulated in sewer systems.
Currently, in many old cities of the United States, the sewer network systems consist of combined sewer systems, separated sanitary sewer systems, and storm water sewer systems. A combined sewer is designed to collect the combined sewage of domestic and industrial wastewater, and storm water runoff in the same pipe. A separated sanitary sewer is designed to collect domestic and industrial wastewater. However, a storm water sewer is used to collect storm water runoff only. During the periods of dry weather or light rainfall, the urban sewer network transports all of the collected combined sewage from combined sewer systems and wastewater from sanitary sewer systems to a treatment plant to receive full treatment before discharging to a nearby water body. However, during heavy storm events, the quantity (flow rate and volume) of the collected sewage and storm water runoff in a combined sewer system may surpass the designed capacity of the sewer system or the treatment plant. When this situation occurs, the excess flows will inevitably overflow to a nearby water body. These overflows are known as combined sewer overflows (CSOs). With increasing frequency super storms in recent years, for example, Hurricanes Katrina, Irene and Sandy, have caused flood and overflow of urban sewer systems and devastating damages to both properties and humans.
Combined sewer overflows can cause serious water pollution problem. The deposition of sewage solids during dry weather in combined sewer systems has long been recognized as a major source of receiving water pollution. One of the underlying reasons for considerable sewage solids deposition is the combined sewer hydraulic design. Dry-weather flow velocities are typically inadequate to maintain settleable solids in suspension, and a substantial amount of solids tend to accumulate in the sewer systems. During rain storms, the accumulated solids may re-suspend, and overflow to receiving waters due to the limited hydraulic capacity of the interceptor. Suspended solids concentrations of several thousand parts per million are not uncommon for CSOs. This can produce shock loadings detrimental to receiving water. Development of a means to control or remove sedimentary deposits is required to prevent their undesirable effects.
The control of CSOs employing structural measures such as sewer separation, storage and treatment has been used in a number of major cities in the United States. Nationwide application of these techniques for the control of CSOs would require expenditures over 100 billion dollars. New strategies are needed to reduce these costs to tolerable limits. Sewer sediment flushing can significantly reduce overall costs when integrated with other upstream management practices and downstream storage tanks. Engineered sewer sediment flushing systems are low-cost control alternatives which can be viewed as an added measure for structural control and treatment. In some cases, the CSO storage-sedimentation facility may be more cost effective for controlling suspended solids and associated pollutants; however, it requires efficient flushing systems for removing tank bottom sediments.
Concern over sewer flushing can be dated back to the Romans. In the U.S., early historical efforts for sewer sediment cleaning occurred in Syracuse, N.Y. at the turn of the century. The method for sewer cleaning is to create a flushing wave to scour and transport the deposited sediments to a storage sump by rapidly adding external water or by quickly opening a flushing gate.
Currently significant work has been invested to achieve a cost effective means to purge the sediment deposited in combined sewers, CSO storage tanks, and storm water conveyance systems via a variety of flushing techniques. Existing flushing technologies include Hydrass®, Hydroself®, Biogest®, Huber Power Flush®. All of these flushing systems require either an external sources of water and/or energy or complex control mechanism. Therefore, United States Environmental Protection Agency (USEPA) further developed a sediment flushing system as disclosed in U.S. Pat. No. 6,655,402 to C.-Y. Fan, which is hereby incorporated by reference. The USEPA's system can be installed either in a CSO storage tank or in a combined sewer. Notably, the invention creates effective hydraulic waves without the use of an outside energy source, but uses water from the storm event itself. However, a major limitation of USEPA's flushing system is that when the water level outside the flushing tank drops slowly (near the opening of the vacuum break pipe), the flushing wave is weak. This is caused by a direct relationship between the completed vacuum break time and the speed at which water is released from the flushing tank.
Therefore, to effectively remove sewer solids from urban drainage systems between storms, a flushing system with high efficiency and cost effectiveness, yet without need of external sources of water and energy and complex control instrumentation, is still urgently needed.
The present invention fulfills the foregoing need by providing novel vacuum break devices useful in automatic vacuum flushing systems and the automatic vacuum flushing systems including these novel rapid vacuum break devices. The vacuum break devices disclosed herein are capable of rapidly breaking the vacuum in a storage tank of a sewer line, thus enabling efficient flushing of sediments and cleaning the sewer system. Thus, the invention provides novel automatic vacuum flushing systems and methods thereof for sewer or storage tank sediment cleaning in urban drainage systems.
In one aspect, the present invention provides an automatic vacuum flushing system for flushing or cleaning sewer or storage tank sediment in a drainage system, comprising a flush water chamber, an air release valve on the top of the flush water chamber, and a vacuum-break device connected to the top of the flush water chamber through a pipe,
wherein the flush water chamber comprises an opening of a predetermined size in its lower part of the drainage downstream side and is in fluid communication with the drainage system through the opening;
wherein the flush water chamber substantially fills up with water from the drainage through the opening when the water level in the storage tank or sewer rises; a vacuum is created in the headspace of the flush water chamber when water in the sewer or storage tank is drained; and when water in the storage tank or sewer falls below a predetermined level, the vacuum-break device rapidly breaks the vacuum, thereby discharging the water in the flush water chamber in a surge to flush the sewer or storage tank.
In another aspect, the present invention provides a sewer line comprising an automatic vacuum flushing system according to any embodiment(s) as described herein.
In another aspect, the present invention provides a vacuum break device for an automatic vacuum flushing system, comprising:
a chamber formed by an outside screen wall, a bottom plate and a top plate;
a plurality of bars installed vertically connecting the top and bottom plates of the chamber to form a frame;
a positioning tube installed vertically on the bottom plate of the chamber;
a plurality of floatable parts, each comprising a central hole, placed along the positioning tube, the floatable parts optionally mounted on the bars of the frame through holes;
a weight positioned above one of the floatable parts; and
a rubber sheet above the top of the floatable parts and directly beneath the bottom opening of the pipe coming from the top of the chamber, the rubber sheet capable of tightly sealing the pipe opening when in position;
wherein the rubber sheet, the floatable parts, and the weight are arranged so that the rubber sheet can seal the pipe opening when water level rises in the sewer or storage tank and during the formation of vacuum when the water in the sewer or storage tank is drained until a predetermined level.
In one embodiment, the floatable parts comprise:
a floating plate at the bottom directly beneath the weight;
a rubber sheet holder on the top to hold the rubber sheet, the holder comprising a plate fixed on the top of a rod, the rod inserted downwardly into said positioning tube so that the bottom floating plate, the weight, the rubber sheet holder, and the rubber sheet are aligned along the positioning tube from bottom to the top, and can freely move up and down along the positioning tube;
wherein the rubber sheet is connected to the weight by two or more strings or chains; and
wherein the rubber sheet moves upward to seal the opening of the pipe when water level rises to move the floatable parts upward; a vacuum is created when the water level falls; and when the water level falls to a predetermined level, the weight applies a force to the rubber sheet through the strings or chains to rapidly break the vacuum.
In another aspect, the present invention provides a vacuum break device for automatic vacuum flushing systems, comprising:
a mechanical part fixed on the top of the flush water chamber encompassing the air release valve, and
a floatable part connected to the mechanical part through a lever system,
wherein the floatable part, through the lever system, causes the mechanical part to suddenly open the air release valve and break the vacuum in the headspace of the flush water chamber, when water level in the sewer or storage tank falls to a predetermined level.
In another aspect, the present invention provides an automatic vacuum flushing system for flushing or cleaning sewer or storage tank sediment in a drainage system, comprising a vacuum break device according to any embodiment described herein.
In another aspect, the present invention provides a method of flushing or cleaning sewer or storage tank sediment in a drainage system, comprising the steps of: providing at least one of the automatic vacuum flushing systems comprising a vacuum breaking device according to any embodiment(s) described herein; and placing said at least one of the automatic vacuum flushing systems in an upstream portion of the drainage system. When water level rises to substantially fill the flush water chamber, the water is drained from the sewer or storage tank to create a vacuum in the headspace of the flush water chamber; and when the water level in the sewer or storage tank falls to a predetermined level the vacuum in the headspace of the flush water chamber breaks rapidly, causing discharge of the water in the flush water chamber in a surge to flush out the sediment from the sewer or storage tank.
The efficiency of sediment cleaning from the sewer or storage tank bottom depends on the strength of the flushing wave. The strength of the flushing wave greatly depends on how quickly the water evacuates the chamber and on the volume of the water in the vacuum chamber. The speed at which water is released from the vacuum chamber greatly depends on how quickly the vacuum breaks. To satisfy this need, two novel vacuum break devices are provided in this invention. The laboratory demonstration has proven that they work in a similar manner to flushing gates, and they can be applied to any field conditions.
The present invention provides a variety of advantages, which include, for example, completely automatic operation; no external power required; no external water supply required, thus enabling flushing with rain or wastewater; self-generated vacuum during natural draining of water outside the flushing tank; quick vacuum break and high flushing strength; high cleaning performance; full flushing action even on small spills (most rain events); minimal maintenance from outside the tank, therefore providing health and safety advantages; easy installation; elimination of odor annoyance; and low material and manufacturing cost.
Additional aspects and advantages of the present invention will be readily apparent to one of skill in the art in view of the following drawings, detailed description and claims.
The accompanied drawings illustrate the details of this invention for automatic flushing systems 1 and 2. They are described as follows:
This invention provides two automatic vacuum flushing systems with newly developed rapid vacuum break devices, respectively, for sewer and storage tank sediment cleaning in urban drainage systems (
Thus, in one aspect, the present invention provides an automatic vacuum flushing system for flushing or cleaning sewer or storage tank sediment in a drainage system, comprising a flush water chamber, an air release valve on the top of the flush water chamber, and a vacuum-break device connected to the top of the flush water chamber through a pipe,
wherein the flush water chamber comprises an opening of a predetermined size in its lower part of the drainage downstream side and is in fluid communication with the drainage system through the opening;
wherein the flush water chamber substantially fills up with water from the drainage through the opening when the water level in the storage tank or sewer rises; a vacuum is created in the headspace of the flush water chamber when water in the sewer or storage tank is drained; and when water in the storage tank or sewer falls below a predetermined level, the vacuum-break device rapidly breaks the vacuum, thereby discharging the water in the flush water chamber in a surge to flush the sewer or storage tank.
In another embodiment, the vacuum-break device is located at the upstream or side of the flush water chamber.
In another embodiment, the vacuum-break device is connected to the pipe on the top of chamber through an elbow.
In another embodiment, the vacuum break device comprises:
a chamber formed by an outside screen wall, a bottom plate and a top plate;
a plurality of bars installed vertically connecting the top and bottom plates of the chamber to form a frame;
a positioning tube installed vertically on the bottom plate of the chamber;
a plurality of floatable parts, each comprising a central hole, placed along the positioning tube, the floatable parts optionally mounted on the bars of the frame through holes;
a weight positioned above one of the floatable parts; and
a rubber sheet above the top of the floatable parts and directly beneath the bottom opening of the pipe coming from the top of the chamber, the rubber sheet capable of tightly sealing the pipe opening when in position;
wherein the rubber sheet, the floatable parts, and the weight are arranged so that the rubber sheet can seal the pipe opening when water level rises in the sewer or storage tank and during the formation of vacuum when the water in the sewer or storage tank is drained until a predetermined level.
In another embodiment, the floatable parts comprise:
a floating plate at the bottom directly beneath the weight;
a rubber sheet holder on the top to hold the rubber sheet, the holder comprising a plate fixed on the top of a rod, the rod inserted downwardly into said positioning tube so that the bottom floating plate, the weight, the rubber sheet holder, and the rubber sheet are aligned along the positioning tube from bottom to the top, and can freely move up and down along the positioning tube;
wherein the rubber sheet is connected to the weight by two or more strings or chains; and
wherein the rubber sheet moves upward to seal the opening of the pipe when water level rises to move the floatable parts upward; a vacuum is created when the water level falls; and when the water level falls to a predetermined level, the weight applies a force to the rubber sheet through the strings or chains to rapidly break the vacuum.
In another embodiment, the floatable parts further comprise a positioning part placed between the weight and the rubber sheet holder, wherein the positioning part has freedom to move upward and downward along the positioning tube and, when water level rises to a predetermined level, applies a lift force to the rubber sheet holder to force the rubber sheet to seal the opening of the pipe.
In another embodiment, the bottom floatable part and the weight have holes traversed through by the same number of bars.
In another embodiment, the number of bars is four (4).
In another embodiment, the vacuum break device comprises:
a mechanical part fixed on the top of the flush water chamber encompassing the air release valve; and
a floatable part connected to the mechanical part through a lever system,
wherein the floatable part, through the lever system, causes the mechanical part to suddenly open the air release valve and break the vacuum in the headspace of the flush water chamber, when water level in the sewer or storage tank falls to a predetermined level.
In another embodiment, the mechanical part comprises:
a shooting part connected to a lever arm of said lever system through a connecting means (e.g., a pin, pivot, or the like) and capable of moving up and down along a positioning rod, the shooting part connected to the top of the flush water chamber through a spring wrapping around the positioning rod, both the spring and positioning rod fixed on the top of the flush water chamber, optionally through a positioning plate, and
a handle fixed on the shooting part, the handle connected to the air release valve through a string or chain,
wherein the shooting part is capable of opening and closing the air release valve through the string or chain connecting the handle and the valve.
In another embodiment, the mechanical part further comprises a supporting structure to hold the pivot of the lever system, and a positioning structure to hold the shooting part in place when the air release valve is closed.
In another embodiment, the floatable part is located at the upstream or a side of the flush water chamber.
In another embodiment, the drainage system is selected from the group consisting of combined sewer systems, separated sanitary sewer systems, and storm water sewer systems.
In another embodiment, the drainage system comprises at least one sewer line or storage tank for one or more of combined sewer overflow, separated sanitary sewer overflow, and storm water overflow.
In another embodiment, the velocity of the flushing water surge is at least at a level sufficient to suspend and flush out the sediment, said level of velocity being dependent on sizes and specific gravity of the sediment or field deposits.
In another embodiment, the level of the velocity of the flushing water surge is at least about 1 m/s, at least about 2 m/s, at least about 3 m/s, or at least about 4 m/s.
In another embodiment, the opening in the lower part of the flush water chamber is at least about one inch above the historical height of the sewer or storage tank sediment layer immediately downstream of the flush water chamber.
In another embodiment, the opening in the lower part of the flush water chamber is at least about two inches, at least about three inches, or at least about four inches above the historical height of the sewer or storage tank sediment layer immediately downstream of the flush water chamber.
In another embodiment, the size of said opening in the lower downstream part of the flush water chamber is determined based on required velocity of the flushing water surge, volume of flush chamber, and field conditions.
In another embodiment, the predetermined water level in the sewer or storage tank for vacuum-break is located at the level immediately above the top of the opening.
In another embodiment, the predetermined water level in the sewer or storage tank for vacuum-break is located within about one inch, about two inches, or about three inches above the top of the opening.
In another embodiment, the volume of the flush water chamber is determined based on the volume of the storage tank or the volume of the total length of sewer line to be flushed so that the velocity of the flushing water surge at least meets the required minimum average velocity to suspend and flush out the sediment from the storage tank or the sewer line.
In another embodiment, the volume of the flush water chamber is at least about 5-10%, at least about 10-15%, about 15-20%, or about 20-25% of the volume of the storage tank or at least about 10-20%, about 20-30%, about 30-40%, about 40-50%, or about 50-60% of the volume of the total length of sewer line to be flushed.
In another embodiment, the volume of the flush water chamber is about 10-20 percent of the volume of the storage tank or about 20-50 percent of the volume of the total length of sewer line to be flushed.
In another aspect, the present invention provides a sewer line comprising an automatic vacuum flushing system according to any embodiment as described herein.
In one embodiment of this aspect, the sewer line comprises a plurality of the automatic vacuum flushing system along the sewer line.
In another embodiment of this aspect, at least one automatic vacuum flushing system is installed per about 300 to about 1500 feet along the sewer line.
In another embodiment of this aspect, at least one automatic vacuum flushing system is installed per about 500 to about 1000 feet along the sewer line.
In another embodiment of this aspect, at least one automatic vacuum flushing system is installed per about 600 to about 800 feet along the sewer line.
In another embodiment of this aspect, the sewer line further comprises a receiver to receive and discharge dry weather flow.
In another aspect, the present invention provides a vacuum break device for an automatic vacuum flushing system, comprising:
a chamber formed by an outside screen wall, a bottom plate and a top plate;
a plurality of bars installed vertically connecting the top and bottom plates of the chamber to form a frame;
a positioning tube installed vertically on the bottom plate of the chamber;
a plurality of floatable parts, each comprising a central hole, placed along the positioning tube, the floatable parts optionally mounted on the bars of the frame through holes;
a weight positioned above one of the floatable parts; and
a rubber sheet above the top of the floatable parts and directly beneath the bottom opening of the pipe coming from the top of the chamber, the rubber sheet capable of tightly sealing the pipe opening when in position;
wherein the rubber sheet, the floatable parts, and the weight are arranged so that the rubber sheet can seal the pipe opening when water level rises in the sewer or storage tank and during the formation of vacuum when the water in the sewer or storage tank is drained until a predetermined level.
In one embodiment of this aspect, the floatable parts comprise:
a floating plate at the bottom directly beneath the weight;
a rubber sheet holder on the top to hold the rubber sheet, the holder comprising a plate fixed on the top of a rod, the rod inserted downwardly into said positioning tube so that the bottom floating plate, the weight, the rubber sheet holder, and the rubber sheet are aligned along the positioning tube from bottom to the top, and can freely move up and down along the positioning tube;
wherein the rubber sheet is connected to the weight by two or more strings or chains; and
wherein the rubber sheet moves upward to seal the opening of the pipe when water level rises to move the floatable parts upward; a vacuum is created when the water level falls; and when the water level falls to a predetermined level, the weight applies a force to the rubber sheet through the strings or chains to rapidly break the vacuum.
In one embodiment of this aspect, the floatable parts further comprise a positioning part placed between the weight and the top place of the rubber sheet holder.
In another embodiment of this aspect, the bottom floatable part and the weight have holes traversed through by the same number of bars.
In another embodiment of this aspect, the number of bars is four (4).
In another aspect, the present invention provides a vacuum break device for automatic vacuum flushing systems, comprising:
a mechanical part fixed on the top of the flush water chamber encompassing the air release valve, and
a floatable part connected to the mechanical part through a lever system,
wherein the floatable part, through the lever system, causes the mechanical part to suddenly open the air release valve and break the vacuum in the headspace of the flush water chamber, when water level in the sewer or storage tank falls to a predetermined level.
In one embodiment of this aspect, the mechanical part comprises:
a shooting part connected to a lever arm of said lever system through a connecting means (e.g., a pin, pivot, or the like) and capable of moving up and down along a positioning rod, the shooting part connected to the top of the flush water chamber through a spring wrapping around the positioning rod, both the spring and positioning rod fixed on the top of the flush water chamber, optionally through a positioning plate, and
a handle fixed on the shooting part, the handle connected to the air release valve through a string or chain,
wherein the shooting part is capable of opening and closing the air release valve through the string or chain connecting the handle and the valve.
In another embodiment of this aspect, the mechanical part further comprises a supporting structure to hold the pivot of the lever system, and a positioning structure to hold the shooting part in place when the air release valve is closed.
In another embodiment of this aspect, the floatable part is located at the upstream or side of the flush water chamber.
In another aspect, the present invention provides an automatic vacuum flushing system for flushing or cleaning sewer or storage tank sediment in a drainage system, comprising a vacuum break device according to any embodiment described herein.
In another aspect, the present invention provides a method of flushing or cleaning sewer or storage tank sediment in a drainage system, comprising the steps of:
providing at least one of the automatic vacuum flushing systems according to any embodiment described herein;
placing said at least one of the automatic vacuum flushing systems in an upstream portion of the drainage system;
allowing water level to rise so as to substantially fill the flush water chamber;
draining the water from the sewer or storage tank to create a vacuum in the headspace of the flush water chamber;
allowing the water level in the sewer or storage tank to fall to a predetermined level so that the vacuum in the headspace of the flush water chamber breaks rapidly, causing discharge of the water in the flush water chamber in a surge to flush out the sediment from the sewer or storage tank.
In one embodiment of this aspect, the drainage system is selected from the group consisting of combined sewer systems, separated sanitary sewer systems, and storm water sewer systems.
In another embodiment of this aspect, the drainage system comprises at least one sewer line or storage tank for one or more of combined sewer overflow, separated sanitary sewer overflow, and storm water overflow
Other aspects of the present invention include vacuum break devices and automatic vacuum flushing systems essentially as shown and described, and use of the vacuum break devices and/or flushing systems as shown and described in a storage tank, a storm water sewer line, or a combined sewer line.
The amount of sediment that can be removed from the sewer or storage tank bottom depends on the strength of the flushing wave. The strength of the flushing wave depends on the volume of the water in the vacuum chamber and on how quickly the water evacuates the chamber. The speed at which water is released from the vacuum chamber greatly depends on how quickly the vacuum breaks.
The following non-limiting examples illustrate certain aspects of the present invention.
The first type of new vacuum break device is illustrated in
A brief description of the various components of a Flushing System using the vacuum breaking device of type 1 (
The second type of novel vacuum break device is illustrated in
A brief description of the various components of a Flushing System equipped with the vacuum breaking device of type 2 (
As a person of ordinary skill in the art would appreciate, the vacuum break devices of the present invention can be in any sizes to suit particular flushing systems based on the need, which could vary depending on various factors known to those skilled in the art.
Existing Laboratory Flume and Flushing Tank (Chamber)
The existing laboratory flume and flushing tank (chamber) were used to simulate a research of sewer or storage tank. The channel is located in the Fluid Mechanics/Hydraulics Laboratory in the Department of Civil and Environmental Engineering at Rutgers University. It is a self-contained, re-circulating channel, designed for use as a student laboratory flume and for small scale sediment transportation studies. The unit consists of a transparent plexiglass channel, a head tank with an adjustable undershot gate, an adjustable tailgate, a reservoir, two circulating pumps, and a flow metering system. The supporting framework incorporates an elevating mechanism for varying the slope of the channel bed. All wetted parts of the equipment are made of non-corrosive materials.
The overall dimensions of the channel are: Length, 19 feet 5 inches (5.92 m); Width, 8 feet 10 inches (2.69 m); Height, 6 feet 10 inches (2.08 m). Working section of the channel is 12 inches (30 cm) wide, 18 inches (46 cm) deep, 15 feet (4.57 m) long (from head gate to tail gate) and is fabricated from 0.5 inch (13 mm) thick, clear plexiglass. The channel discharges into a 32.0 ft3 (0.91 m3) reservoir fabricated from a composite lamination of fiberglass and rigid PVC foam core.
The flushing chamber was placed at the head of the flume. Outside dimensions of the tank are: 36 inches (0.91 m) high, 36 inches (0.91 m) long, and 11 inches (28 cm) wide. One-inch (25 mm) thick Acrylic sheet was used to make the top cover, bottom floor, and four sidewalls. Therefore, the inside dimensions of the tank are: 34 inches (86 cm) high, 34 inches (86 cm) long, and 9 inches (23 cm) wide. Three 6-inch (15 cm) holes are cut on the top cover of the tank. Two of the three holes on the top cover are closed with thermal plugs, and the third hole is connected to a 6-in PVC standpipe. A vertical gate/plate is attached to the downstream wall of the flushing tank. A metal frame is clamped to the gate/plate to hold it against side of the tank and to maintain a desired downstream gap height.
Materials Used in Experiments
Water used in the flushing tests was taken from the public water supply tap in the laboratory.
Experimental Equipment
A digital video camera was used to record water movement during laboratory flushing. The video camera records 30 picture frames per second. Spatial positions were established using markings on the flushing tank and the flume.
Experimental Design
The laboratory tests were conducted based on three flushing systems: One is USEPA's automatic vacuum flushing system; the other two are based on the present invention (
For flushing system 1 of this invention, The rapid vacuum break device 100 was mounted to the bottom of the standpipe. For flushing system 2 of this invention, the vacuum break device 200 was mounted on the top of the flushing tank.
Experimental Procedures
Without intending to be bound, an illustrative example of the experimental procedure is described as follows:
Laboratory test results from use of the USEPA's flushing system indicated that the strength of the flushing wave greatly depended on the length of vacuum break time. The shorter the vacuum break time was, the higher the strength of the flushing wave became. The laboratory demonstrations indicated that the vacuum break time greatly depended on the falling speed of the water level outside the tank. However, for sewers or storage tanks with water levels falling gradually, this flushing system may not work efficiently for sediment removal due to the weak flushing wave created.
In contrast, the laboratory demonstrations using the flushing systems 1 and 2 of this invention have shown that they worked very effectively, in a similar manner to flushing gates. When the water level fell to a predetermined level, the vacuum broke suddenly in both systems. As a person of ordinary skill in the art would be able to appreciate, in principle these new systems can be applied to any field conditions.
As a person of ordinary skill in the art would also appreciate, the vacuum break devices of the present invention could also vary in shape, so long as they can serve to rapidly break the vacuum when water fills up in the storage tank until a pre-determined level and thus enabling release of water to cause a current to flush sediments downstream. Therefore, it will be understood by those skilled in the art that numerous and various modifications can be made without departing from the spirit of the present invention. Therefore, the various embodiments and examples of the present invention described herein are illustrative only and not intended to limit the scope of the present invention.
This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/779,039, filed on Mar. 13, 2013, which is incorporated herein by reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 1918678 | Wirz, Jr. | Jul 1933 | A |
| 3661261 | Lemke | May 1972 | A |
| 4905325 | Colditz | Mar 1990 | A |
| 5333630 | Jepsen | Aug 1994 | A |
| 5387054 | Richter | Feb 1995 | A |
| 6655402 | Fan | Dec 2003 | B1 |
| 20100032032 | Davenport | Feb 2010 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20140261735 A1 | Sep 2014 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61779039 | Mar 2013 | US |
