Patent Application
20120216843
The present invention relates to a UV disinfecting system for waste water and drinking water having a number of UV radiators arranged in cladding tubes, said cladding tubes being configured essentially symmetrically to a longitudinal axis, as well as a cleaning device for the cladding tubes.
It has been known for a long time that microbiologically loaded liquids such as waste water and drinking water may be treated by means of UV radiation. Here, even clarified waste water can be disinfected to such a degree that it may be introduced into rivers and bath waters. Drinking water can be disinfected by means of UV radiation, so that it is suitable for human consumption.
For disinfecting, low-pressure mercury radiators or medium-pressure mercury radiators are used, which are protected by cladding tubes and immersed into the water to be treated. The radiators and the cladding tubes are made from UV permeable material. In practice, quartz is used for this. The external surface of the cladding tubes is in direct contact with the surrounding liquid, and this is where any material depositing during operation over time separates from the surrounding liquid. This may be inorganic material such as, for example, lime. However, these may also be deposits of organic material.
As a result of the deposits on the external surfaces of the cladding tubes, the UV radiation emitted into the liquid will be reduced. In connection with the invention, reference will subsequently be made to an incrustation of the surface.
In order to remove such incrustations it was previously suggested to remove the radiators after an interruption of operation and then to clean the cladding tubes. It has also been suggested to clean radiators in closed channels in the case of an interruption of the liquid flow by flooding the channel with a liquid containing an acid. These solutions are not feasible for larger installations. Even an interruption of operation is disadvantageous.
Following that, various approaches for automatically cleaning the cladding tubes were developed. Each of these solutions is based on rings that are placed around the cylindrical cladding tubes and are then pushed along the cladding tubes by a drive. The mechanical contact between the ring and the cladding tube will then effect the cleaning. Depending on the application, various solutions have proven to be feasible. In detail, the following solutions are known from the prior art:
U.S. Pat. No. 5,418,370, which is incorporated by reference, shows a cleaning device for a radiator cladding tube having a ring bearing against the cladding tube. The ring includes a chamber that is in communication with the cladding tube and into which a cleaning liquid is fed. Drive means are provided in order to move the ring along the cladding tube. In the course of this, the cleaning agent will gradually come into contact with the entire cladding tube surface and will effect there the removal of the incrustations. A similar solution is known from U.S. Pat. No. 6,013,917, which is incorporated by reference. Here, the cleaning ring includes two seals spaced from one another in the axial direction of the cladding tube, which seals seal the chamber against the surrounding liquid. Here it is suggested to feed the cleaning liquid into the chamber via a refill system, so that during a movement of the cleaning ring in the axial direction, the cleaning liquid will also come into contact with the surface over the entire length of the cladding tube and can separate the incrustations. What is problematic with this type of cleaning rings is the behaviour in the case of calcareous incrustations on the cladding tube surface. The chambers inside the rings are reliant on a seal against the surrounding liquid which is as good as possible. This seal gets damaged by calciferous incrustations, so that the cleaning liquid cannot be retained in the chamber and gets lost or an increased consumption occurs. In the case of drinking water applications it is also undesirable if substantial amounts of the cleaning liquid flow over into the drinking water.
DE 10010127 A1, which is incorporated by reference, suggests a cleaning ring, wherein the surface of the cladding tube is surrounded by an open-pored foam material. Cleaning liquid is fed into this foam material. Here, the elasticity of the foam material ensures that the cleaning ring will rest well against the surface of the cladding tube at all times. By virtue of the open pores, the cleaning liquid cannot escape into the surrounding water to an undesirable degree. This technical solution has proven to be useful for particularly calciferous liquids. However, in continuous operation there is a risk that the cladding tubes will get scratched.
There are further cleaning rings that operate without the supply of cleaning liquid. These cleaning rings effect a purely mechanical cleaning of the cladding tube surface. Thus, a radiation system for the water of fish ponds is known from U.S. Pat. No. 5,942,109, which is incorporated by reference. What is suggested is a cleaning ring for a cladding tube of a UV radiator, which has brushes on the inside thereof. The brushes rest against the surface of the cladding tube and clean the cladding tube surface by means of an axial movement. For an application in the area of drinking water or waste water, such a solution has so far not been suggested. However, in continuous operation here, too, wear of the brushes and damage to the cladding tube surface have to be expected.
Finally, DE 10125507 A1, which is incorporated by reference, shows a purely mechanically acting cleaning ring comprising a guide chamber and blades orientated vertically relative to the cladding tube surface in the guide chamber. The blades are configured as a helical ring which extends elastically around the cladding tube surface and, due to its elasticity, rests against the surface. This cleaning device adjusts itself to compensate for any wear. A high surface pressure of the cleaning ring against the cladding tube surface is achieved. Therefore the cleaning effect is continuously good. However, here, too, there is a risk that the cladding tube surface will be damaged over time.
Therefore, no UV radiation system is known from the prior art, wherein the cladding tube surface can be cleaned during running operation in a contactless manner, so that any damages of the cladding tube surface are eliminated.
Disclosed herein is a UV radiation system. The cladding tube surfaces of which may be cleaned during running operation in a contactless manner.
A UV disinfection system for waste water and drinking water, comprises a number of UV radiators arranged in cladding tubes, said cladding tubes being configured essentially symmetrically to a longitudinal axis, as well as a cleaning device for the cladding tubes, which comprises the following: at least one cleaning ring for each cladding tube, which surrounds the cladding tube, at least one drive means for driving the cleaning ring in the direction of the axis, wherein the at least one cleaning ring is disposed at a distance (d) from the surface of the cladding tube, openings directed towards the cladding tube are provided in the cleaning ring, and supply means for the supply of pressurised liquid under high pressure into the openings are provided, so that the pressurised liquid is directed as a cleaning jet onto the surface of the cladding tube.
Since the at least one cleaning ring is provided at a distance from the surface of the cladding tube, openings directed towards the cladding tube are provided in the cleaning ring and supply means for supplying pressurised liquid into the openings are provided, so that the pressurised liquid is directed onto the surface of the cladding tube as a cleaning jet, any scratching of the cladding tube surface will be reliably prevented due to the absence of any mechanical contact between the cleaning ring and the cladding tube, whilst the supply of liquid under high pressure in the space between the cleaning ring and the cladding tube surface will loosen any incrustations building up there.
If a plurality of cleaning rings is provided with a common holder and a common supply for the pressurised liquid, a common drive and a common pressure supply may be provided for a plurality of radiators of a radiation device. If further the drive of the cleaning rings in the axial direction of the cladding tubes is carried out hydraulically, the pressure of the cleaning liquid may be used for the drive. In this case, only one external pressure source is required in order to provide the supply for both the cleaning and the drive thereof. The drive may advantageously be effected here by means of a double acting hydraulic cylinder. However, it may also be contemplated to provide a spindle drive via a turbine driven by the pressurised liquid.
Exemplary embodiments of the present invention will be described below by means of the drawings, wherein:
The cleaning ring 1 has a continuous channel 4 on the inside facing the axis 3, which channel is on the one hand fed via a connection bore 5 and on the other hand is in communication with nozzles 6 which extend from channel 4 to the inner circumferential surface of the cleaning ring 1. The base body 2 is delimited by an annular external circumferential surface 7 and two face sides 8 and 9 facing in the direction of the axis 3. The nozzles 6 are distributed over an inner circumferential surface 10 of the cleaning ring 1. The inner circumferential surface 10 is inserted in the base body 2 as part of a separate annular component 11. Next to the annular inner circumferential surface 10, the component 11 has a slope 2 extending towards the axis 3 and a ring area 13 having a narrower cross section. The ring area 13 in turn has an annularly circulating groove 15 on its external circumferential surface 14, which groove is open towards the outside.
The groove 14 is used for retaining the cleaning ring 1 in a drive and guide device.
A tubular cladding tube 42 having a circular cylindrical cross section is indicated in
For producing the two-piece construction of the cleaning ring 1, the base body 2 is initially made, which has part of the annular channel 4 as an internally circulating groove which is open towards the axis 3. The inner ring 11 is made with the slope, the inner circumferential surface 13, the outer circumferential surface 14 and the groove 15 as well as with a large number of nozzles 6 and is then inserted into the base body 2, so that the nozzles 6 are in communication with the channel 4 which is otherwise closed towards the outside.
During operation, the channel 4 is fed with a liquid under high pressure via the connection 5, which liquid then exits through the nozzles 6 into the internal space of the cleaning ring. The pressure here is 5 bar to 200 bar, preferably 20 bar to 100 bar and in particular approximately 50 bar. As a source for the pressurised liquid, a reciprocating pump, as it is known for example from high-pressure cleaning devices, is preferably provided. As the pressurised fluid, water is preferably used which may also be taken from the stream of water to be treated or of water that has already been treated. It is possible, but not necessary, to add chemical cleaning agents or solvents or acids.
The holder 20 is provided with supply lines 23. One supply line 23 is respectively provided for each cleaning ring 1. This supply line is connected to a connection bore 5 of the respective cleaning ring 1. A common manifold line 24 leads from a pressure connection 25 to the supply lines 23 approximately in an H-shaped configuration. Guides 26 are provided in relation to the axial direction 3 laterally adjacent to rows 21 and 22 of cleaning rings 1, which guides allow the holder 21 to be guided on guiding rods orientated parallel to the axis 3.
Moreover, the cleaning rings 1 are retained in the grooves 15 (not shown here), so that they are firmly seated in the holder 20 in the direction of the axis 3.
Finally,
The holder 21 from
In the course of this, the cleaning rings 1 will not come into contact with the surfaces of the cladding tubes 42 by virtue of the distance d.
The pressurised liquid itself may also be used as a drive, if the nozzles 6 are orientated at an angle towards the cladding tubes 6. In this case, a recoil component will be created in the direction of the axis 3, which recoil component effects a driving force in one direction. The return movement may then be carried out by means of a simpler drive, for example by means of a single acting hydraulic cylinder.
During operation, the assembly according to
As a result, any incrustations will not get into the area of the minimum distance between the inner ring surface 13 and the cladding tube 42, but will be flushed in the opposite direction. Therefore, such incrustations cannot penetrate into this annular gap. In this way it is ensured that the ring 1 does not come into mechanical contact with the cladding tube surface 32. Any scraping contact with the surface of the cladding tubes 42 due to the axial movement of the cleaning rings 1 will therefore be carefully avoided. The cladding tube surface will therefore not be damaged during the cleaning operation.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2009 039 654.3 | Sep 2009 | DE | national |
This application is the U.S. National Phase patent application of PCT International Application No. PCT/EP2010/005385, filed Sep. 2, 2010, which claims priority to German Patent Application No. 10 2009 039 654.3, filed Sep. 2, 2009, the contents of such applications being incorporated by reference herein.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP10/05385 | 9/2/2010 | WO | 00 | 5/14/2012 |
