SU1194462A1 - Method of controlling the process of filtering - Google Patents

Abstract

METHOD OF MANAGING THE FILTERING PROCESS by adjusting the flow rate of the filtrate discharged from the near-wall eons of the filter, depending on the quality of the filtrate on its filter. the progress and termination of the filtering operation when indicative of the quality of the filtrate of a given value is reached, characterized in that, in order to improve the filter performance, the flow rates of the treated water and the filter & that is removed from the wall zone and the dependence on the ratio of the measured flow rates change treated water with correction for the quality of the filtrate at the outlet of the filter. g (/)

Description

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The invention relates to methods for controlling the filtration process and can be used in the purification of natural and waste waters in food, chemical, oil refining and other industrial sectors.

The aim of the invention is to increase the filter performance.

The method is implemented as follows.

The initial water, after passing through the stop valve I, enters the upper part of the filter 2, passes through the granular layer of the load 3 and is drained off by the drainage device 4 through the filtrate collector collector 5, on which the filtrate quality analyzer 6 and the stop valve 7 are located. in the near-wall zone of the filter 2, it is retracted by an additional annular drainage device 8 and through the check valve 9 and the control valve 10, the Analyzer 6 continuously monitors the changes in the quality indicator filter ta. Conductometers, analyzers with ion-selective electrodes, photoelectric colorimeters, etc. can be used as an analyzer for the quality of the filtrate. The signal from analyzer 6, converted to a standard converter 1, is fed to the input of differentiation device 12, in which the derivative of the quality indicator of the filtrate is calculated. In the measuring device 13, the signals are subtracted from the differentiation device 12 and from the driver 14, which is adjusted to the desired value of the filtrate index. The error signal is fed to the input of the controller 15, the output of which through the converter 16 acts on the control valve 10, changing the flow rate of the substandard filtrate discharged from the near-wall zone of the filter 2, thereby maintaining the required quality value of the filtrate. This means that by continuously changing the flow rate of the filtrate discharged from the near-wall zone of the filter 2, the value of the filtrate quality indicator at its output is maintained at a predetermined level. As the granular layer of the load 3 depletes, the amount of non-consumer 94462 increases.

filtrate discharged from the near-wall zone, and the quantity of conditioned filtrate decreases on the filter cake 2, i.e. reduces its performance. In order to maintain a constant capacity, it is necessary to increase the water supply to the inlet of filter 2. Sensors 17 and 18 continuously measure the costs of unconditioned filtrate discharged from the wall zone and the treated water, supplied water supplied to the input of filter 2. Signals from sensors 17 and 18 and

15 are converted into standard measuring devices 19 and 20 and fed to the input of measuring device 21, which calculates the value of the ratio of flow rates, simultaneously

20 with a signal from the driver 22, which is tuned to the desired value of the ratio of substandard flow and treated water. To the input of the driver 22

25, a signal is received from the controller 15, which adjusts the cost ratio depending on the quality indicator value of the filtrate. Since this signal characterizes not only 30 the quality of the filtrate, but also

degree otkrggi regulating valves 10, t, e. the flow rate of the off-grade sub-standard filtrate at the next time point, the values of the ratio of the flow rates in the driver unit 22 are adjusted for the subsequent change in the flow rate of the sub-standard filtrate, which improves the speed of the control system. Output signal measuring

The device 21 is fed to the input of the ratio controller and through the converter 23 acts on the control valve 24, changing the flow rate

45 treated water inlet

filter 2, depending on the correlation of costs of substandard filtrate corrected in terms of the quality of the filtrate and treated water. The value of the filtrate quality indicator is continuously recorded by the automatic device 25 associated with the three-position control device 26, the relay of which is set to the Minimum filtrate quality indicator value corresponding to the start of withdrawal of the non-conditioned filtrate from the filtrate wall quality recipient corresponding to the end of the filter cycle. When the quality of the filtrate reaches a predetermined value, which indicates depletion of the granular layer in the near-wall zone, a three-position control device relay is triggered to the minimum value of the quality indicator of the filtrate, and a signal is given to open the stop valve 1. When the quality of the filtrate begins to exceed the maximum allowable value, t . it becomes impossible to keep it withdrawing off-spec leached filtrate from the near-wall zone, triple-control relay device set to the maximum filtrate quality indicator is triggered, and is signaled to close the shut-off valves 1.7 and 9. The filter cycle ends. Example. A medium hard water of 2.5 mEq / l is fed to the inlet of the sulfo coal filter. A hardness meter with a measuring range of 0-30 µg eq / l is selected as the filtrate quality analyzer. The signal from the hard disk is converted by the converter into a standard electric signal of direct current and is fed to the input of the differentiation device in order to calculate the derived stiffness value. The output signal of the differentiation device and the reference signal, adjusted for a hardness value of 25 µg-eq / l, from the driver are fed to the input of the measuring device, where the incoming signals are subtracted and the mismatch signal is generated, which is fed to the controller input. The output of the regulator, formed in accordance with the law of regulation and converted into a standard pneumatic signal by an electropneumatic converter, acts on a control valve with a pneumatic diaphragm actuator, which leads to a change in the degree of opening of the valve and a change in the flow rate of the filtrate removed from the near-wall zone of the filter by an additional 1L4 device . Thus, by continuously adjusting the flow rate of the unconditioned flow discharged from the near-wall zone of the filter with the valve, the stiffness of the filtrate at the outlet of the filter is maintained at the required level of no more than 25 μg-eq / l. The flow rate of the nonconforming filtrate and the flow rate of the water to be treated are continuously measured by induction flow meters with a measuring range of 0-8 m / ch and 0-100 m / h, which include flow transducers and measuring devices. The output signals of the direct current are fed to the input of the measuring device, which calculates the value of the ratio of the flow rates, simultaneously with the signal from the setting device, which is adjusted to the required ratio of the flow rates of the non-conventional filtrate and the treated water. The error signal from the measuring device enters the regulator input, the output of which, converted by an electropneumatic transducer to a standard pneumatic signal, acts on the control valve with a pneumatic diaphragm actuator, changing the degree of valve opening; This leads to a change in the flow rate of the treated water at the filter inlet, depending on the correlation of the flow rate of the non-conditioned filtrate and the treated water in terms of the rigidity of the filtrate. The rigidity value of the filtrate at the filter outlet is recorded by an automatic device with an electric regulating device, the lower limit of which is set to a hardness value of 22 µg-eq / l, which corresponds to the beginning of the discharge of substandard flow from the near-wall zone, and the upper limit of the setting is set to 27 eq / l, which corresponds to the depletion of the granular layer of loading and the end of the filter cycle. When a hardness of 22 µg-eq / l is reached, the device sends a signal to open an electrically operated valve. When a hardness of 27 µg-eq / l is reached, the device sends a signal to close the motorized shut-off valves. Filter cycle finishes with.

Claims (1)

METHOD FOR MANAGING THE FILTERING PROCESS by controlling the flow of filtrate discharged from the wall aeon of the filter to a factor of ¹ depending on the quality of the filtrate at its outlet and terminating the filtration operation when the filtrate quality indicator reaches a predetermined value, characterized in that, in order to improve the performance of the Filter, additionally measure the flow rates of the treated water and the filtrate discharged from the parietal aeon, and depending on the ratio of the measured flow rates, the flow rate of the treated water is changed from projection on the quality of the filtrate at the outlet of the filter.