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High-pressure cleaning often results in strong air flows. This interaction produces a high and low pressure jump at the nozzle., i.e. there is negative pressure in front of the nozzle (nozzle head) and positive pressure behind the nozzle (jet area). When the cleaning nozzle passes side branches (laterals), seal water can be blown out or sucked out from private drain traps (e.g. of toilets or washbasins) hence causing odour nuisances. The pressure … |
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The following measures can reduce the occurrence of odours:
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A form of quality control carried out during the cleaning operation involves assessing the noise created by the deposits during suction and visually inspecting the flushing water. Acoustic assessment: mud, rocks or solidified deposits cause noise as they are vacuumed up and hit the suction tube. This provides insights into the degree of contamination and the progress of the cleaning. (Image: Cleaning debris) (Image: Cleaning debris) (Image: Cleaning … |
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Visual assessment: A visual inspection of the flushing waters content and colour provides a general idea of the deposit situation and the cleaning progress. (Image: Visual inspection of the flushing water) (Image: Sewer manhole inspection) |
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(Image: Selection of the nozzle and the jet angle) Nozzle: • Number and diameter of openings • Type of nozzle inserts • Jet deflection in the nozzle? (Pressure loss) (Image: Deposits sewer - mixtures of organic and mineral substances) Sewer channel (Cleaning objectives): • nominal size, length, depth material • structural condition • quantity and type of deposits • flow condition and level of backup. (Image: Combined high pressure flushing and suction … |
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Congratulations! You have successfully finished this module. Next you will have the opportunity to review the newly acquired knowledge with an interactive questionnaire. You can of course still navigate back to any point in the modules if you wish to review a specific point or subject. Stay curious! |
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May 15, 2012 An essential part of high-pressure cleaning are the cleaning nozzles. This module covers the complex task of choosing the optimal cleaning nozzle for the respective application, as there are a multitude of nozzle types with different features available. After completing this module, you will have a sound knowledge of:
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Feb 16, 2011 In these investigations, the position of the cleaning nozzle lying on the pipe invert remains unaltered. It is positioned in such a manner that any damage that occurs in the pipes and pipe joints can be observed. The investigations are carried out at various pressure levels, whereby the pressure begins at 75 or 100 bar and is raised by steps of 25 bar up to the maximum pressure of the cleaning system. Each level of pressure is maintained for 1 minute … |
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Nov 04, 2004 In order to simulate long-term loading, the respective cleaning nozzle is pulled through the 12 m long test section 40 to 60 times with a constant water pressure of 150 bar measured at the HP pump and a constant speed of approximately 4 m/min. This pull-through speed was determined on the basis of evaluation of several applications in practice as well as calculation documentation. In the course of the investigations, 30 l of sand, gravel and stones … |
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Nov 04, 2004 Rehabilitation and Maintenance of Drains and Sewers High pressure Water Jetting Process (HP Water Jetting Process)
Unprofessional application of the high pressure water jetting process can cause pipe damage in the form of grooves, chipping, cracks or holes in pipe walling and linings (Abschnitt 2.1) (Bild 3.2.3.1) (Bild 3.2.3.1). Especially dangerous moments occur … |
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The high pressure water jetting process (HP water jetting process) [Lenz96] is the almost universal process, used in about 90 % of all sewer cleaning processes for removing deposits within the scope of regular maintenance as well as for cleaning as a preparatory measure for sewer inspection or rehabilitation. It can usually not be used when hardened deposits are present or for removal of flow obstacles, e.g. internally projecting laterals, artificial … |
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Cleaning the Sewer The section to be rehabilitated must be free from deposits and other flow obstacles. In this case it is cleaned by means of the high-pressure jetting method. If obstacles are found which cannot be removed by this method of cleaning then they are removed using a sewer milling robot. The results of the cleaning are rechecked by TV inspection and documented before the start of rehabilitation.
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