Application of the hottest turbidity circulating d

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Application of turbidity circulation detection system in filter operation

Abstract This paper introduces a method of dynamic monitoring of filter, that is, filtered water circulation detection system. It is to transform the sampling part of the original turbidity meter, that is, the original installation of the Middle East is an unknown factor. The sampling pipe of the filter collecting tank is extended to each filter, and an automatic control part is added at the same time. The continuous determination of single port filter is realized, and good results have been achieved in the production and operation of about 3.6~4 kg nylon products per vehicle

applying the cycling sampling to ensure that the sample will not slip during the experiment; System to detect the humidity of finished water

Abstract Based on the normal online humidity detecting system, changed the sampling position to each filter Under the controller conducting, each filter‘s effluent can be sampled in sequence, so that all the filters turbidities are read with one turbidity detector at the same internal time.

keywords filter turbidity continuous detection

filter is an important link in the water plant water production process. Generally, the method to evaluate the performance of filter is to measure its various parameters (such as turbidity of outgoing water, backwash strength, expansion coefficient, etc.). In addition, most of the existing water plants install turbidity meters at the filtered water collecting tank. As the mixed water sample is sampled here, the turbidity information of the effluent from each filter cannot be provided. Therefore, it is necessary to establish a simple, fast and intuitive means of filter performance monitoring. In order to achieve this goal, this paper introduces a method of dynamic monitoring of the filter, that is, the filtered water circulation detection system

I. existing problems

we selected a group of filters in a water plant to measure the water quality of its collecting tank and each filter respectively (see Table 1), and the filter has been running for 36 hours at the time of measurement

Table 1. Determination of turbidity of filtered water (NTU)

filter number 1234567891011 in addition to a large number of standard courses, 12

turbidity of each filter 0.48 0.47 0.61 0.63 0.56 0.71 0.65 0.46 0.54 0.52

turbidity of collecting tank


it can be seen from the above table that there is a large difference between the turbidity of mixed water and that of each filter, which cannot well reflect the turbidity of filtered water.Water quality

II. Method principle

on the basis of the original turbidity automatic detection system, the sampling part is reformed. Change the sampling point originally set in the water collecting tank to extend the sampling pipeline to the filter, install solenoid valves and automatic control units, and conduct cyclic sampling and turbidity detection for each filter

its working principle is: when the single port filter meets the detection conditions under normal conditions, it will enter the detection queue orderly (as shown in Figure 1, the queue length is 12 bits). When there are special circumstances, such as out of operation due to maintenance, in the manual position, and the water level is lower than 130 cm, it will not enter the turbidity detection queue

when No. 1 filter is at the detection position, the drain valve of its sampling pipe is closed and the inlet valve is opened. Then the filtered water is introduced into the water collecting tank (defoaming and flow stabilization), and then sent to the turbidimeter for detection. The computer collects and processes the data. Exit the detection position after the detection of filter 1. If the filter operates normally, enter the waiting detection queue and enter the next cycle. At this time, in order to ensure that the water sample entering the turbidity meter is the filtered water of the current filter, it is necessary to drain the old water in the water collector. At the same time, No. 6 filter enters the ready detection position. After the old water in the water collector is drained, it moves to the left and enters the detection position for detection. In this cycle, the filtered water of each filter tank working normally is detected. The detection time of each filter tank is 5 minutes, and the detection cycle of 12 (a group) filters is 60 minutes

III. operation test of cycle detection system

1 Comparison between automatic detection and manual detection

in order to eliminate the systematic error of instrument detection, we calibrated the hach1720c turbidimeter of the system with hach2100p portable turbidimeter. Then, the operation data of the circulating detection system is compared with the data of HACH portable turbidimeter, and the results are shown in Table 2

Table II. Comparison of circulating detection system and manual detection results

filter No. 1234567891011 12

manual detection 0.24 0.92 1.20 0.54 0.34 0.92 0.54 0.15 0.36 0.13 1.12 0.51

system detection 0.38 1.23 2 0.01 0.92 0.57 1.13 0.66 0.55 0.59 0.26 1.60 0.74

error (%) 58 33.7 67.5 70.4 67.7 22.8 22.2 267 63.9 100 42.9 45.1

as can be seen from the table, The two results are quite different. After analysis, it may be that the flow entering the turbidity meter now has a great impact on the measurement results of the system

2. Influence of influent flow on the system

to confirm the previous speculation, we adjust the flow of the influent ball valve of the turbidimeter according to the head of each filter, and then measure the turbidity to get Figure 2

it can be seen from the figure that when the sampling flow of the system is within the range of 400-600ml/h, the error range of the detected data is between 2.6-2.8%, which meets the requirements of analysis error. So we chose this flow range

within this flow range, we use the filtered water circulation detection system to detect the filtered water of a single filter for 1413 times for 20 consecutive days, with the maximum error of 16.5%. The results were compared with those of manual detection. Statistical data are as follows:

Table 3. Detection error after flow adjustment

error range 5% 5-10% 10-15% 15%

detection times 95842626 3

proportion (%) 67.830.2 1.8 0.2

from the data in the table, we can see that detection with error greater than 10% only accounts for 2% of the total times, and the operation result is satisfactory

III. monitoring of filter performance by circulating detection system

since the system can continuously and stably measure the turbidity of filtered water, we use this method to feed water into each filter in the water plant

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