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(Table: Comparison of different types of vacuum pumps) |
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The maximum suction lifts of the solid-liquid-mixtures amount to between 9 m to 12 m, and can only be realised by the addition of air to the suction flow by means of openings near the end of the suction tube. These processes decrease the specific weight of the solid-liquid-mixture to be extracted and, at the same time, increase the flow velocity in the suction tube. Suction lifts between 12 to 25 m require the usage of ejectors that are positioned … |
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Hoses used for high-pressure cleaning include:
(Image: Cleaning of a catch basin using a suction) (Image: High pressure flushing hose in use) |
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High-pressure flushing hoses, subsequently also called HP-flushing hoses or hose, serve to transport the flushing water under high-pressure to the nozzle, and have to be certified to the maximum operating pressure of the high-pressure system [ATV/VKS]. They are available in the nominal sizes of 1/2" (13 mm), 3/4" (19 mm), 1" (25 mm), 1 1/4" (32 mm) and 1 1/2" (38 mm), and in lengths ranging from 120 m up to 250 m. They are designed for a maximum operating … |
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The hoses are stored on reels from which they are unwound in part or in full length depending on the length of the section to be cleaned. In addition to the large hose reel, combined high-pressure flushing and suction vehicles with water recovery technology are equipped with a second smaller hose reel with a HP flushing hose ranging in size from 1/2" or 3/4", it is used to clear congestions in the sewer laterals. (Image: Arrangement of the large and … |
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The nominal size of the hose is dictated by the actual flow rate. Generally, municipalities and water utilities generally have their guidelines and standard specifications. (Table: High-pressure flushing hose size in relation to the flow rate) |
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(Table: Technical data for textile reinforced high-pressure hoses made of rubber) |
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(Table: Technical data for high-pressure rubber hoses reinforced with textile and steel fibres) |
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(Table: Technical data for high-pressure rubber hoses reinforced with textile and steel fibres) |
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(Table: Technical data for high-pressure hoses made of plastic) |
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There exists a general distinction between rubber and plastic hoses, although their structure is essentially the same. (Image: High pressure flushing hose construction)
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Construction of a high-pressure hose with high reinforcement (Image: Construction of a high pressure hose with heavy reinforcement) (Table: Advantages and Disadvantages of low and high HP reinforced hoses) |
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(Table: High-pressure flushing hose – Comparison Rubber vs. Plastic) |
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(Image: Protective hose guide - on the vehicle) During cleaning procedures in sewer systems, high-pressure flushing hoses are exposed to mechanical stress due to internal pressure, as well as tensile, bending and frictional forces. In practice, guide rollers or hose guides are used to reduce these stresses. They help guide the flushing hose and the nozzle to a horizontal position in the sewer without kinks, therefore avoiding hose contact at the edges … |
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Further measures to increase the service life of high-pressure flushing hoses include:
(Image: Example of damages to the outer cover of a high pressure flushing hose) (Image: Example of damages to the outer cover of a high pressure flushing hose) (Image: Example of damages to … |
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Operational errors in the use of high-pressure hoses:
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Suction tubes are used to extract the waste material collected in the manhole. (Image: Suction tube in manhole) (Image: Suction tube with damming flaps) Images: Extraction of the waste material from a manhole using a suction tube [Image: Prof. Dr. Ing. Stein & Partner GmbH] |
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In practice, abrasion-proof rubber tubes are used for this purpose. They have to meet the following requirements
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According to [DIN30705:1991], the nominal size of the suction tube needs to correspond hydraulically to the volumetric flow rate of the vacuum pump. (Table: Recommended nominal sizes of the suction tube in reference to the volumetric flow rate of the vacuum pump) |
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Sep 27, 2012 (Video: High pressure water jetting with a combined vehicle with water treatment technique) Animation: Combined high pressure flushing and suction vehicle with water treatment technology [Image: visaplan GmbH]. This object is only visible in the online version of the module. |
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May 27, 2013 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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