Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – With means applying electromagnetic wave energy or...
Reexamination Certificate
1999-03-17
2001-02-27
Gorgos, Kathryn (Department: 1741)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
With means applying electromagnetic wave energy or...
C210S748080, C405S113000
Reexamination Certificate
active
06193938
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for treating liquids with UV-radiation.
2. The Prior Art
These devices are preferably used in sewage purification (or treatment) plants. Before the purified (or prepurified) waste water effluent from the sewage treatment plant is discharged into natural waters, it always has to be disinfected a number of times. The waste water purified in the treatment plant is for this purpose subjected to a treatment with ultraviolet radiation (UV-radiation).
The devices provided for such treatment have an irradiation chamber through which the waste water flows. The irradiation chamber is equipped with UV radiation sources. These sources are formed by UV radiation lamps, which are enclosed in protective tubes made from quartz for protecting the lamps against the waste water. These protective tubes are permeable to the UV-rays which, therefore, can penetrate the waste water.
In addition to the irradiation chamber, the known devices comprise an outlet chamber arranged downstream of the irradiation chamber. The waste water exposed to the UV-radiation is received in the outlet chamber; and the now-purified, disinfected waste water can be discharged from there into the discharge system.
EP 0 687 201 B1 discloses a purification device with an irradiation chamber designed in the form of a completely closed chamber shaped like a tube. The waste water is forced through the irradiation chamber under pressure, which leads to an increased flow rate of the waste water in the irradiation chamber.
In such devices, the outlet chamber adjoining the irradiation chamber in the downstream direction has installed elements in the form of terminating walls serving as weir elements. The terminating walls are designed, for example, in the form of shutoff flaps (or shutters), overflow weirs or motor weirs extending vertically relative to the direction of flow of the flowing waste water. The water dams up in front of the installed elements. The water then flows off over the so-called overflow edges into the discharge system. Thus the water flows over the upper edges or below the shutoff flaps or shutters, and is then admitted into the natural waters.
In the known devices, the installed elements of the outlet chamber serving as weir elements comprise a plurality of rectangular or also triangular individual chambers with vertical termination walls serving as damming walls. These elements are installed next to each other. This increases the overall length of the overflow edge for the waste water. Therefore, even relatively large quantities of waste water can flow off over the overflow edge and then be discharged into the drain system without substantially raising the water level.
Since the known devices require a great overall length for the available overflow edge in order to avoid high variations in the water level, the dimensions of the chambers are very large when viewed in the direction of flow of the waste water. Thus the complete device requires a great deal of overall space. This, furthermore, leads to increased expenditures with respect to manufacturing and operating costs.
Another drawback is that the waste water received in the outlet chamber from the irradiation chamber impacts quasi-vertical termination walls of the elements installed in the outlet chamber. This impact will slow down the water contacting these walls. This causes the water to back up, and such backwater may extend back into the irradiation chamber upstream. This will lead to uneven flow of the waste water. Such nonuniform flow, however, is disadvantageous for treating waste water with UV-radiation. It is possible to provide a free space between the irradiation chamber and the outlet chamber. This free space is in the form of a calming zone for the flowing waste water in order to prevent the back-up of water from extending back into the irradiation chamber. However, such a calming zone increases the overall dimensions of the device even more, so that the costs of such a device are further increased again.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a device for treating liquids with UV-radiation and in particular for treating prepurified waste water. This device can be constructed at substantially more favorable costs and in a more space-saving manner while maintaining optimal disinfection and treatment of liquids. It is of no significance in this connection whether the irradiation chamber is in the form of a chamber closed on all sides, or in the form of a chamber structured in the known manner with an upwardly open channel with a bottom and two side walls.
This object is achieved in accordance with the invention by providing a device for treating prepurified waste water liquid with UV-radiation comprising an irradiation chamber through which the liquid flows; UV-radiation sources positioned in said chamber; an outlet chamber following the irradiation chamber in a downstream direction of flow and provided for draining off the liquid, said outlet chamber being an upwardly open channel with a lower channel bottom and two attached side walls, and having at least one weir element; said weir element having a damming wall with upper overflow edges over which a dammed up liquid overflows and drains off, said damming wall slowing down the flow of the liquid and forming a rear termination of the outlet chamber; the damming wall extends in the direction of flow as an upwardly raised extension of the channel bottom in a slanted manner from a front end to a rear end of the outlet chamber at a flat angle of smaller than 60° relative to channel bottom; several individual weir elements are arranged on the slanted damming wall, said weir elements being separated from each other; said weir elements are formed by upwardly extending tubes, said tubes being open at both ends and having top ends forming overflow edges; and the damming wall is provided in the locations where the tubes are secured on the damming wall with openings corresponding to cross sections of the tubes for draining off the liquid flowing over the overflow edges of the tubes.
According to the invention, the damming wall or termination wall impacted by the flowing waste water extends in the form of a raised extension on the bottom of the channel. This extension rises in a slanted manner from the front end to the rear end of the outlet chamber at a flat angle of less than 60° relative to the bottom of the channel. Thus the flowing waste water no longer impacts a vertical damming wall. The waste water is thereby only gradually slowed down by the slanted damming wall, so that the water flow rate changes only slightly. This means that no backup, or only a minor backup, of the liquid will occur. Thus the even flow of the liquid desired in the irradiation chamber is not influenced, or is only influenced in an insignificant way. A calming zone between the irradiation chamber and the outlet chamber thus can be omitted in connection with the invention. This permits a reduction in the cost of the device as defined by the invention. Furthermore, the overall space requirements of the device of the invention can be reduced as well.
Furthermore, with the device of the invention, several individual weir elements, which are separated from each other, are arranged on the slanted damming wall. Each weir element is formed by an upwardly extending hollow tube, which is open at both ends. The upper ends of the tubes form the overflow edges for the overflow and for draining off the waste water. In the locations where the tubes are secured on the damming wall, the wall is provided with openings corresponding with the cross sections of the tubes for draining off the waste water flowing over the overflow edges of the tubes.
At its top end, each tube has overflow edges, which are predetermined by the circumference of the tube. Since provision is made for a multitude of tubes, a large overall length of the overflow edges is available to the liquid. Thus the device can operate in a satisfactory
Collard & Roe P.C.
Gorgos Kathryn
Tran Thao
Wedeco AG Water Technology
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