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UDC 628.12:62-531.3
KARGIN S. A.
Analysis of Electric Power Losses in the Course of Operation of a Group of Pumps Equipped with Adjustable Drive
Summary
Calculations of the power losses in pump units with aggregates operating simultaneously, one of them is adjustable, are presented. The main advantage of a control scheme with one adjustable pump is a relatively low cost of an apparatus part. But additional power losses connected with reduction of rotation frequency of a pump impeller of the adjustable pump in the course of operation of unregulated pumps under conditions of maximum output are unavoidable. Calculations of these losses made with the use of vector diagrams of hydraulic capacity of pumps make it possible to develop a structure of a power efficient pumping unut characterized by acceptable cost of equipment and minimal power expenditures to maintain the preset pressure in a pressure line.
Key words:
pressure , pump unit , frequency of pump impeller rotation , capacity , hydraulic capacity , frequency of feeding voltage , frequency converter
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UDC 628.336.42
Zlatkovskii O. A.
EKOTON chamber-membrane filter presses
Summary
The wide range of chamber and membrane filter press application alongside with the design and control system improvements allow considering this type of equipment as a solution to numerous typical and special tasks of industrial slurry and wastewater filtration. At the same time the large variability of tasks necessitates designing a wide standard series of filter presses with different specifications. Individual filter press selection and manufacture suppose considering both filtration properties of particular slurry and the parameters of the operational flow scheme, mode of operation, site-specific conditions, production resource, characteristics of the related equipment, filter press place in the general layout of the filtration area.
Key words
wastewater , dehydration , capacity , filtration , moisture contents , suspension , filtering cake , chamber filter press , membrane filter press
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UDC 621.65:62-531.3
Usachev A. P.
Method of estimating the efficiency of pumping unit frequency regulation (to be discussed)
Summary
The method of estimating energy saving from using frequency regulation of the pumping unit capacity in water supply systems is presented. The estimation of the capacity efficiency of pumping units is carried out only from the energy saving resulting from the use of frequency regulation instead of throttling (other saving components are not considered). To estimate energy saving it is required to compare the power consumed from the grid in the existing scheme of the regulation by penstock gate throttling and in the frequency regulation scheme. Then the energy saving in monetary form shall be compared with the expenses for retrofitting the frequency regulation system. The method is based on the graphical analysis of the pump operation point parameters in the operating group and optimized for the use in water supply systems operating by the pressure.
Key words
capacity , power saving , frequency regulation , pumping unit , efficiency evaluation , throttling
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UDC 628.211:53.072.12
Karmazinov F. V., Zhitenev A. I., Shunto I. P., Kuz’min Valentin, Kostenko I. G., Martiugin V. A., Pulin O. V., IGNATCHIK V. S., Ignatchik S. Iu., Kuznetsova N. V., Fes’kova A. Ia.
Specific features of hydraulic mode simulation for combined sewers
Summary
Hydraulic simulation of sewerage networks in big cities in practice involves input of large quantities of data on all the network sections including the yard ones. This complicates significantly and extends the time required for fulfilling the task. Therefore developing express-method of hydraulic simulation of transporting facilities of sewers will provide for reducing the amount of input information without reducing the accuracy of the calculation results. In order to substantiate the method experimental studies in one of the sanitation districts of Saint-Petersburg were carried out. By experiment it was stated that the use of simplified hydraulic simulation with account of only street networks (without the yard ones) resulted in 20% overestimation of the calculated flows. Herewith the express-method of calculating wastewater flows in combined sewers depending on the rainfall intensity that allows the use of hydraulic simulation with account of only street networks where virtual tanks are simulated with a capacity equal to the capacity of the yard networks connected to them has been experimentally substantiated. The method error is 2–5%.
Key words
sewerage pumping station , capacity , combined sewer , flow regulating unit , stochastic method , unsteady random flow
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UDC 628.218
Karmazinov F. V., Zhitenev A. I., Shunto I. P., Kuz’min Valentin, Spivakov M. A., Pulin O. V., IGNATCHIK V. S., Ignatchik S. Iu., Kuznetsova N. V.
The use of stochastic methods in determining the required capacity of regulating units in combined sewers
Summary
The flows of wastewater removed by the combined sewers are characterized by high irregularity caused by the random nature of rainfall and snow melting. One of the ways of improving the reliability of these systems is the introduction of flow regulating units. They have been designed to diverse wastewater between the sanitation districts in case of emergency or in case of the actual wastewater inflow in one of them, e. g. because of over-estimated rainfall, exceeding the actual capacity of the regulating units. The method of determining the required capacity of the flow regulating units with the use of stochastic methods was developed. By the example of the wastewater disposal system of Saint-Petersburg it was stated that the required supply of the sewage pumping station (SPS No. 6) functioning as a regulating unit between the left-bank and right-bank sanitation districts was of random nature and was distributed according to the exponential law with the increasing probability of using the modes with lower supply.
Key words
sewerage pumping station , capacity , combined sewer , flow regulating unit , stochastic method , unsteady random flow
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UDC 628.147.2
Emelin V. I., Azeev A. A.
Productivity of a Complex of Equipment for Trenchless Repair of Pipelines by Means of a Combined Sleeve Drawing
Summary
Methods of the determination of productivity of the complex of equipment for trenchless repair of pipelines by means of composite covering in the course of drawing the combined sleeve with due regard for influence of basic constructive and technological features is offered. Reserves of the productivity increase owing to enlargement of the bay’s length, combination of some operations, taking into account characteristics of covering and other factors are determined. Five conditions of the equally effective designing of details of the complex of equipment are formulated.
Key words:
capacity , pipeline , trenchless repair , complex of equipment , composite coverings , combined sleeve
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UDC 628.292.001.24
DAGILEV M. A.
Calculating the capacity of a receiving tank of a sewage pumping station
Summary
Methods of designing pumping stations according to the requirements of the updated version of SNiP 2.04.03-85 – «Set of rules 32.13330.2012. Code. Sewers. Public utilities» are presented. The basic requirements of the regulatory document and pumping unit manufacturers to the design of pumping stations are considered. It has been established that to provide for correct designing the minimum effective capacity of the pumping station receiving tank with several single-type pumps meeting the requirement to the number of pump starts is necessary: it should not exceed the maximum permissible number of starts for a definite time period. It is evident that the maximum number of starts occurs when all the normal pumps are in operation except one that is operating in turns. A formula of calculating the required effective capacity of a pumping station receiving tank with several single-type normal pumps has been derived. An optimal principle of pump operation at similar pumping stations is determined, pump operation modes, their start and shutdown levels are considered. An example of calculating the effective capacity of a pumping station receiving tank is set. Possible reducing the pumping station footprint is shown. The use of the suggested formulae for calculating the effective capacity of a pumping station receiving tank with guaranteed failure-free operation of the pumping units during the entire life cycle and retaining the manufacturer’s warranty is substantiated.
Key words
sewerage pumping station , capacity , pump , receiving tank , effective capacity , cycle time
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