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(Image: Economic analysis of high pressure cleaning vehicles 2) |
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The selection of the most economical vehicle type can only be made in conjunction with a comprehensive operational concept for the cleaning of the planned drains, sewers and various structures within the drainage system. |
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Depending on the vehicle type, there exist
or both types of pumps can be used at the same time. (Image: HP piston pump) (Image: Vacuum pump) Images: High-pressure piston pump (left) und vacuum pump (right) [Image: Prof. Dr. Ing. Stein & Partner GmbH] |
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(Table: High-pressure pumps as per [KA 4/97 ]) |
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The pumps are arranged behind the driver's cab and are driven by the vehicle's engine through an independent transmission and v-belt. (Image: Pumps drive system) |
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The pumps installed in the vehicles have to meet the following performance requirements [ATV/VKS] [Gütes03] [FI-Müller]. (Table: Performance parameters and standard values for high-pressure pumps subject to the nominal size of the sewer) |
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Piston pumps, also called plunger pumps, are the most commonly used types of pumps in cleaning vehicles (Animation). Occasionally, a hydraulically driven high-pressure water pump that directly converts oil pressure into water pressure is used [Geib2002]. (Image: Piston pump components) (Video: Ventil of the high-pressure plunger pump) |
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(Table: Comparison of the types of high-pressure pumps used in cleaning vehicles) |
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(Table: High-pressure pumps) |
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Removing the accumulated waste material from the respective manholes is of essential importance for the success of the sewer cleaning procedure. Vacuum pumps with 0.6 bar negative pressure and induced volumetric flow rate of 680 m3/h to 4,000 m3/h are usually used for this purpose. (Image: Liquid ring pump - Detail) (Image: Liquid ring pump - front view) (Video: Rotary vane pump) |
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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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