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1. 2 User Manual 16 06 2014 The following information is displayed Flow Total N is the number of taps connected to a pipe rem aa Aiow Binomial 1 column is the maximum number of tap open 0 20 an 0 40 at the same time respecting the condition T out It is ar 1 1 known as the inverse or negative binomial law CALA i ial 209 al ili i i 1 05 Binomial 2 column is the probability of failure with the AE ALTARE given number of tap for instance with a total of 6 taps a 6lo 02 750 178 5 0157 1 26 i o i o 70 00 77 8 75 2 0 150 1 35 5 or less taps will be open 99 99 Yo of the time 6 taps Moo oot tome will only be open 0 01 of the time Binomial 3 column is the ratio between the tap open and tap closed for the binomial distribution representing the proportion of taps to be assumed open It is represented on the chart by the red line Fsim is the regression of the binomial 3 column according to the following function Fim a a with the constant calculated by the macro when the button Calc abc is clicked It is represented on the chart by the purple line Flow l s is the average probable flow per tap using the regression curve Total flow l s is the total probable flow to use to design a pipe connected to N taps 3 0 00 1100 0 100 0 0 200 100 0 0 80 00 1 0 94 If you see a warning Too steep this mean that your regression curve is too sudden and that the tot
2. For instance a pipe connected to 2 taps can be selected of 3 different diameters the smallest one of OD 20mm will have losses of 21 8 m or 2 1 bar per 100 m of pipes the medium one of OD 25mm will have losses of 7 46 m 100m and the largest one of 32mm will have losses of 2 3 m 100m The attached scheme illustrates a short distribution system deserving 10 taps Using the previous simultaneous factor flow and SDR we can quickly find the P4 head losses for each as shown in the next Se a an table Assuming an available head of 80m 500 M a 300 p The total losses for the first tap is of AH 13 54 154 37 34 8 9 74 7m P1 500 10 50 2 69 13 5 N p2 400 5 40 374 150 leaving a marge of 5m of pressure P3 500 2 25 7 46 37 3 For the second tap P4 400 1 25 223 8 9 AH 13 5 15 37 3 9 7 75 5m with P5 150 1 20 6 48 9 7 a marge of 4 5m of pressure The calculation should be first done for the longest section which will define the smallest admissible pipe diameter that can be used then the shortest section can be calculated lf there is too much head losses with the biggest admissible pipes smallest losses other solutions should be studied such as changing the layout installing a equalization tank or increasing the delivery pressure Tutorial on Distirbution Pipe docx 4 5 LWI Distribution Pipe 1 2 User Manual 16 06 2014 3 Make accurate design with the calculation sheet In the next tab you access to the real desig
3. calculate the constant values of a regression curve Fsim a b V N c best fitting the given distribution You can still play a bit with the values a b and c and round them to have a clean function Tutorial on Distirbution Pipe docx 2 5 LWI Distribution Pipe 1 2 User Manual 16 06 2014 The constant a represent the horizontal asymptote towards which the function will converge thus it should be smaller than the average flow a DWd PF 24 3600 Q The constant c define the beginning of the curve and is closely link to the binomial criteria ranging from 5 to 5 The constant b define the curvature and range usually from 0 5 to 3 To compare the simultaneous factor with the peak factor you have the possibility to enter it PF with the Daily Water not only the peak thus the average flow per tap AFT can be calculated and compared to the flow per tap of the regression of the binomial distribution For a certain number of taps the AFT might be bigger than the flow obtain with the simultaneous factor Then for pipes delivering water to more taps the flow obtain with the peak factor should be used This approximate number of taps is given in as MT DP minimum number of taps to use the demand pattern This value closely linked with a constant if you want to use only the simultaneous factor use a as the asymptote if you want to use quickly the demand pattern take it a small as reasonably possible it means where your regression c
4. Distribution Pipe 1 2 User Manual 16 06 2014 How to use the Distribution Pipe tool 1 Create a simultaneous curve adapted to your context or choose an existing one 2 Use the table for quick calculation of your distributions pipes 3 Make accurate design with the calculation sheet 1 Define the specific simultaneous curve for your context lf the water consumption pattern in your context differs from the western standards at least one tap per person with a Rural pattern consumption up to 200 liters per day per person it might be good to define a specific simultaneous curve for your 10 f context me Before starting to use this tool you should have defined the daily demand pattern 7 x according to the chapter 5 Water 0 00 3 00 6 00 9 00 12 00 15 00 18 00 21 00 0 00 demand 50 1 PT peak time in hours Define the peak or high demand time this is the time during which the demand is expected to be important it can be taken as the time where the demand ratio is higher than 100 generally should be between 8 and 14 hours 2 PWd Peak water demand in liter Define the average water demand at a tap during the defined peak time this represent usually between 70 to 95 of the total demand of the tap for all the day 3 Q Flow in liter per second Define the average expected flow PT at your tap this can range from 0 1 liter per second up to 0 3 PWd liter per secon
5. al flow will indeed decrease which is physically impossible This is usually due to a Tout too small or too big for taps with small daily demand If you don t manage to correct it by changing the Tout the best is to adjust manually the constants a b and c On the chart you will see in red the binomial 1 KNs E distribution according to the given 5 N es al specification You can play a bit with the sox SS different figures to see their influence on the y SS Ss S Binomial distribution 7 EEE A A ee The purple line represent the regression n sssr Se SE SESar with the constant a b and c The other curves represent predefined N EPPP Ssss distribution that should guide you to define SSS your curve 1 10 100 1 000 Std tap 1009 0 00 100 Std tap is the curve respecting the French standard DTU 60 1 defining plumbing calculation In most of developing countries the quantity of water distributed per tap is much higher thus it can be assumed that this curve shows the minimum requirement Heavy usage this curve represent also a rather small demand per tap but with a situation where simultaneous flow can be expected to be important such as in a hotel or school Max represent 98 6 Yo a 2 3 4l 5 40 92 100 6 8 9 10 27 62 90 Once you are happy with your distribution click on the button Calc abc this will
6. d a good value is 0 2 I s hours S S lf you have accurate figures for the pattern another option is to work just with the peak hour IN this case the Peak time is one hour the PWd is the daily consumption divided by 24 times the peak factor The Excel Sheet will calculate the time during which your tap need to be open to deliver the required quantity with the given flow WT PWD Q in minutes obviously this time should be shorter than the peak time If it is the same or close to it it means that the taps are almost always open in this case there is no need to work with the simultaneous factor it can just be estimated that all taps are open at the same time and the design done with a continuous flow Then it will calculate the percentage of the time during which the tap will deliver water during the peak time or in other word the WT probability that the tap is open Prob working time per peak Prob 22 time WT PT In 3 4 The last figure to enter is the maximum time during which it is acceptable to have more taps open than the design value T out in other words the time during which the actual pressure and T out flow will be lower than the design This value will give the probability for the cumulative binomial distribution it should be of few seconds 1 to 30 and give a ratio with the time span between 0 2 and 0 01 oO d Tutorial on Distirbution Pipe docx 1 5 LWI Distribution Pipe 1
7. n tool it works the same way as Gravity pipe kindly refer to its tutorial to know how to use it more in details Use the Edit Nodes command to add delete or change types of nodes Fill in all the yellow cells with the base data Description Taps Elevation Length Roughness and Sing losses Then adjust the diameters so that the energy is dropping regularly A B Name of project Node Type Total Descriptio Example Nb of et aan esa on aes Elevation zim _ Length Lim Sim factor eee ing im Energy im 80 73 6 51 12 5 Payn imp oo 230 281 256 69 5 1 Elevation m on a g u a amp r D ta mF lev ation Po Energy i pam Selection So 800 1000 1200 1400 1600 Profil en long m Tutorial on Distirbution Pipe docx 5 5 LWI
8. urve is not too far from the binomial distribution 2 Practical use of results with the Table The table on the next Tab can be used to select quickly diameters of plastic pipes for simple situations First the average flow per tap in liter per second should be given Then the SDR Standard Dimensional Ratio is the outside diameter divided by the thickness of the pipe selected If the calculation is done for another fluid than water the viscosity Nu can be changed The minimum and maximum accepted water speed in the pipe can be modified Head losses will be shown only for pipe diameter respecting these criteria Min Max 2 18 32 3 23 39 The two columns below will give the maximum and minimum diameter respecting the speed limits The constant a b and c of the first tab will be used to calculate the simultaneous factor If you want to use other values you can just change them but be aware that the link will then be lost ON Piero ia 1 00 In the column below the Fsim is calculated for certain number 2 1 00 of taps and the probable flow calculated This flow will be used 3 100 to calculate the head losses in the pipes Tutorial on Distirbution Pipe docx 3 5 LWI Distribution Pipe 1 2 User Manual 16 06 2014 Head losses in meter for 100m length The table will give the head losses in meter per 100m of pipe for the admissible diameter according to the number of downstream taps

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