FR2533909A1 - Process and plant for controlling water treatment by electrolysis for the protection of water distribution systems. - Google Patents

Abstract

Process for controlling water treatment by electrolysis for the protection of sanitary or industrial water distribution systems, according to which a determined quantity of aluminium is introduced into a pipework 1 of the system, which is deposited by electrolytic dissolving of an aluminium electrode 3 inserted into the said pipework, in the form of alumina hydrate in the latter, characterised in that it consists in injecting, in a servo-controlled manner, into the electrode 3, an electrolysis current whose intensity corresponds to the dimensions of the said electrode and in regulating the quantity of electricity as a function of the water circulation flow rate and of the desired aluminium concentration, the said regulation being carried out by an all-or-nothing control of the duration of electrolysis, starting with a predetermined minimum value.

Description

 The present invention relates to a process for regulating the treatment of water by electrolysis for the protection of sanitary or industrial water distribution networks, according to which a determined quantity of aluminum which is deposited is introduced into a network pipe, by dissolution. electrolytic of an aluminum electrode inserted in the pipe, in the form of alumina hydrate in the latter.

In the field of water treatment, a treatment known under the designation "water treatment by electrolysis" is intended to prevent scaling and corrosion of the pipes of the sanitary or industrial water distribution networks and consists in suspending certain quantities of alumina hydrate per volumetric unit of water,
However, the problem posed is to inject determined quantities of electricity in the form of an electrolysis current per volumetric unit of water. The difficulties arise from the fact that the water consumption regimes vary considerably as a function of time, so that the formation of colloidal alumina suspension having the desired stability and physical properties requires the dissolution of aluminum under narrowly defined conditions.

 The stability and the particular properties of the colloidal suspension of alumina are linked to the conditions of diffusion of the AI +++ ions in the medium. The de-stability domain of the alumina hydrate suspension is strictly limited to a maximum concentration under penalty of formation of inactive alumina hydrate, therefore superfluous and undesirable in water.

On the other hand, a shortage of alumina hydrate is not serious for the anti-corrosion effect.

 However, the formation of suitable alumina suspensions requires a current density at the level of the electrolysis electrode (anode), defined to within 20%. As the surface of the 1 "electrode is chosen during construction, this amounts to imposing the applicable intensity.

 In addition, another problem is posed by the considerable difference existing between the average flow and the peak flow, because the electrolysis must be carried out over as long periods as possible, followed by cuts as long as possible.

 In addition, there is a minimum current value, below which the electrode may passivate.

 These problems are solved using the method of the type indicated previously characterized according to the invention in that it consists in injecting in a servo-controlled manner into the electrode an electrolysis current, the intensity of which corresponds to the dimensions of the electrode and to regulate the quantity of electricity as a function of the flow rate and of the desired aluminum concentration, said regulation being carried out according to an all-or-nothing control of the duration of electrolysis, from a value predetermined minimum.

 According to a preferred mode of implementation, we measure the real value of the water flow in the pipeline, we measure the actual treatment current delivered by the elec, trode in the form of an amount of electricity, we send these data as well as the set values of the desired concentration of alumina and of the capacity of a buffer tank mounted: in the pipeline and whose capacity is adapted to the flow of the latter, to a control and calculation unit which, after comparison with threshold values, controls a modulation of the processing current sent to the electrode.

 As can be seen, the adaptation of the quantity of electricity to the quantity of water flowing is obtained by varying the electrolysis time and the all-or-nothing regulation makes it possible to respect a predetermined minimum duration, making it possible to 'preventing the formation of alumina of undesirable quality accompanying a treatment which is too divided in time, and the choice of an intensity corresponding to one twentieth of the maximum flow rate associated with a balloon playing the role of integrator constitutes a good compromise.

 The present invention also relates to an installation for implementing this process, which is characterized in that it consists of a unit for measuring the flow of water in the pipeline, in which a buffer tank is mounted. containing an aluminum electrolysis electrode, a device for supplying and measuring the treatment current sent to the electrode and a control and calculation unit for the treatment current injected, the output of which is connected to the input of the current supply and measurement device and which has three inputs, one of which is connected to the output of the flow measurement unit, the second of which receives the concentration reference values alumina required and the capacity of the flask and the third of which receives, in a feedback loop, the value of the treatment current measured in the supply and measurement device.

Other characteristics and advantages of the invention will emerge from the description given below by way of example and taken with reference to the appended drawings, in which
Figure I shows a general layout diagram of the installation according to the invention,
FIGS. 2 and 3 show the diagram of a flow meter respectively in longitudinal transverse section and in a plan view section,
FIG. 4 shows the diagram of the detector contained in the flow meter,
FIG. 5 illustrates in detail the circuit for processing the signal from the detector before it is sent to a control and calculation unit,
FIGS. 6A and 6B show the general diagram of the connections of the electrical circuit of the installation,
Figure 7 shows the power supply and control circuit of the electrod-e,
FIG. 8 represents the circuit for measuring the processing current sent to the electrode,
FIG. 9 shows the map of the general supply of the various electrical and / or electronic circuits of the installation,
Figure IO shows the control board of the electrode,
FIG. II reproduces the map of the analog / digital conversion circuit for transmitting signals between various circuits and the control and calculation unit for the installation,
FIG. I2A and FIG. I2B illustrate the map of the front face of the installation comprising display devices and indicators associated with controls of the installation,
FIG. I3A and FIG. I3B show the "microprocessor" card of the circuit of the control and calculation unit of the installation,
Figures I4 and I5 respectively represent the general flowchart and the regulation program implemented in the installation according to the invention.

 In FIG. 1, representing a simplified diagram of the installation, it can be seen that in a water circulation pipe I are inserted, on the one hand, an electrolysis cell 2 formed from a buffer tank of a capacity adapted to the flow rate D of the pipe and equipped with an aluminum electrode (anode) 3, and on the other hand, a volumetric meter 4 modified into a flow meter.

 The electrode 3 is connected to a device 5 for supplying and measuring the electrolysis current, sent to the electrode, and receiving a control signal from a unit 6 for regulating and calculating control. An input from this unit 6 is connected to the output of the flow meter 4, while a second input from unit 6 receives setpoint signals of the required concentration of alumina and the capacity of the flask and a third input6 receives, according to a feedback loop 7, the value of the treatment current, measured in the device 5 for supplying and measuring the electrolysis current.

 Furthermore, the unit 6 is connected to a display unit 8 (display) for the concentration of aluminum and the capacity of the tank, the maximum current and the maximum measurable flow and the indication of the established electrolysis current, regulation delay and over-regulation.

 The flow measurement is carried out using the flow meter 4 illustrated in FIGS. 2 and 3 and adapted to specific needs.

We know that in domestic distribution, it is common to encounter installations whose average use is only 1/10 th of the instantaneous peak flow. Typically, an installation consuming 6m3 of water per day must be able to pass a peak flow of 20 m3 per hour. In addition, about half of the total consumption takes place at flows lower than I / I0 of the peak flow and more than 10% of the total consumption takes place at flows lower than
I / I00 of the peak flow. Under the flow conditions mentioned above, a precision of 5% on the total quantity flowed would require a flowmeter having a detection threshold and an absolute precision better than 2/1000 th of the peak flow.

 The flow meter 4 is a volumetric meter (nominal flow: 3 m3h, maximum flow 8 m3h) modified into a flow meter.

 The lower part of the meter includes an injection box 9 which encloses a vertical axis turbine IO.

Two series of practical holes II in the side wall of this box allow the water to come in and out.

The water circulates inside the box and causes the turbine to rotate. In fact, the entire volume of water does not pass through the injection box; there is a small direct communication orifice not shown and adjusted by a calibration screw. The upper part of the meter includes an incremental encoder symbolized in I2 .

The counter 4 generates a signal whose frequency is a function of the flow rate. Its flow (DenI / s) / frequency (fen Hz) transfer function can be compared to two straight line segments, the slope break corresponding to a frequency of I7 Hz - for low flow rates (f I7 Hz): D = 0, 0086I (f + O, I3) - for high flow rates (f.I7 Hz): D = 0.00906 (f-0.71-)
The non-proportionality is due to the direct communication orifice (the calibration screw is not adjusted) and to sliding phenomena.

 The incremental encoder I2, not shown in detail, consists of a disk with seven metallized sectors driven by the turbine, and a variable reluctance proximity detector I3. This was chosen instead of optical detectors, because the latter cause soiling problems and Hall effect detectors require relatively large magnetic fields.

The detector I3 used is, for example, of a type known under the trade name "VISOLUX" type NT5, the diagram of which is shown in FIG. 4. I1 comprises a transistorized oscillator with two identical transistors I4, I5 in conventional symmetrical mounting, operating at I MHz. The internal resistance between pins 16 and I7 in free oscillation is
# 600 ohms. The introduction of a metallic body into the o-scillating field (detection field) modifies the internal resistance which becomes # 5 ohms. The main characteristics of this detector are, by way of example
- supply voltage 5V to 8V
- oscillation frequency I MHz
- response time I50
- resistance difference ;; 600 ohms to # SHohms
- detection distance 5 mm
- detected control surface IIxIIxI mm
- reproducibility (tempera-
constant ture) t 0.04 mm
- hysteresis 0.4 mm
- temperature drift 53.5 pm / C
- operating temperature - 250C to +60 C
-weight 12 g
The reluctance detector I3 sends out a pulse at each passage of a metal sector, said pulses being counted and then managed by the control and calculation unit described below. This arrangement, which largely eliminates, a good number of frictions mechanical, allows dynamics and precision of the counter necessary for the application envisaged in the invention.

 The pulse signal from the detector I3 (fig.4) is a current of I mA 'in the presence of a metallic body and 7 mA in the absence of a metallic body. A weak alternative component of I MHz is superimposed on it. This signal is amplified by a transistor 18 (see Figure 5) used as an amplifier with current threshold and low-pass filter. This filtering is not sufficient to eliminate the alternative component, its action is completed by a Schmitt I9 flip-flop (type 74LSI4). The output of this attacks the input of a monostable flip-flop 20 (type 74LS12I) which reduces the signal to a series of pulses of IO Ss. These pulses are counted by the control and microprocessor computing unit described below.

 On the various electrical diagrams, the various capacitors and resistors are represented in a conventional manner by indicating their respective appropriate values.

 Below before continuing the detailed description of the various circuits and units of the installation, a general description will be given of the general arrangement of these various elements with reference to FIG. 6.

According to this diagram, the various circuits are distributed on various integrated circuit cards comprising
- the so-called "front panel" card intended for the display 21,
- the "general food" card 22,
- the "electrode control" card 23,
- the analog (digital) conversion card 24,
the “microprocessor” card 25 not visible in this figure, but entirely shown in FIG. I3,
a connector "micropressor card" 26 to which this card 25 is connected, the cards and the connector being read together by their corresponding terminals designated by their conventional abbreviated names well known in the field of electronics and data processing .

 In addition, in this FIG. 6, two power transformers 27 and 28 are shown, connected to the network symbolized with the reference 29 and one of which, 27, is connected to the power supply card, and the other of which, 28 , is connected by means of a rectifier 30 to the card 23.

 Furthermore, the mass of the electrode housing at 31 has been shown, a transistor output circuit 32 connecting an output of the card 23 to the electrode 3 and a connection circuit 33 leading to the detector I3.

 Hereinafter we will describe with reference to FIGS. 7 and 8 the device for supplying the electrode and for measuring the treatment (electrolysis) current, FIG. 7 representing the circuit for supplying and controlling the electrode 3 while FIG. 8 represents the circuit for measuring the treatment (electrolysis) current sent to the electrode.

 The circuit of FIG. 7 comprises a supply loop connected to the secondary of the transformer 28 at several secondary voltages, by the rectifier circuit 30 and including a power transistor 34 operating as a switch delivering the current to the electrode 3 and controlled on its base, by a transistor 35, the base of which is connected to the control and calculation unit 6. The emitter of the transistor 34 is connected by an adjustable resistor 36 to a first terminal of the rectifier 30, while its collector is connected to the 'electrode 3.

 In addition, this circuit comprises a measurement resistance 37 of low ohmic value mounted transversely in this supply circuit (28, 30, 34, 35, 36) between a ground terminal connected to the electrolysis cell 2 and whose l the other end is connected to the actual current measurement circuit of FIG. 8, described below.

 It will also be noted that the establishment of the current (that is to say the treatment of the water) is indicated by an indicator lamp 38 ("VT") connected by a transistor 39 to the connection line between the transistor 35 and the control and calculation unit 6, an output port of which sends this control transistor a control signal.

 Furthermore, the adjustable resistance 36 of 6.8 ohms and the transformer 30 with several secondary voltages allow the adjustment of the electrolysis current, the maximum value of which is 5A.

 The value of the treatment current depends on the flow rate and the capacity of the water tank to be treated; The impedance of the electrolysis cell 2 is inversely proportional to the surface of the electrode 3. The treatment current is obtained, at constant current density, by means of a supply at constant potential. 2 being variable as a function of the aqueous medium in which it is located, the additional adjustment by resistance thus allows fine adjustment.

 The actual intensity is continuously measured and counted by the control and calculation unit.

 The current measurement is carried out via resistor 37 of 0.22 ohms. The voltage drawn across this resistor is amplified and filtered by an operational amplifier, 40 used as a low-pass filter.

The amplification coefficient of 7.2 makes it possible to obtain a voltage of 10 V at the output of the amplifier when the electrolysis current is 7A. (This current value which is in fact never reached, simplifies the software). The time constant is O, I s (see Figure 8).

 The output voltage of the amplifier 40 is converted by an analog digital converter 41 of the double ramp integrator type ("DATEL" type ADC-ET8B). The digital output (8 bits: SO to S7) is read by an input port of the control and calculation unit 6. This converter with a Ceint 42 integration capacity of 68 pF, requires an input current of 1O) jA full scale and a reference current of 2OjiA. For an input voltage of 10 V full scale and a reference voltage of 5 V, the resistor R. 43 is 1 Mohm and the resistor Brief 44 is 250 Kohms. The adjustable resistor R g 45 of 220 Kohms adjusts the full scale. A potentiometer P z 46 of 10 kohms adjusts the zero, compensating for the offset voltages of the integrator of the analog digital converter 41 and the amplifier 40.

 In addition, a circuit 47 is provided which constitutes an integrated voltage regulator intended to provide the negative supply of −5 V necessary for the operation of the analog digital converter.

 The input signal "conversion order" is a pulse of 500 ns minimum. I1 is provided by a bit of an output port of -unit 6. The maximum duration of the conversion is I, 8 ms. The output signal "give valid" is at level O when the state of the digital outputs (SO to S7) is changing. I1 is read by a bit from an input port of unit 6 of order and calculation.

 FIG. 9 illustrates the card 22 of the general power supply of the circuits, which includes two rectifiers 48 and 49 whose inputs and outputs are connected to the different terminals, the role of which is indicated in the figure, and which comprises appropriate decoupling capacitors such as 50, 51, as well as circuits 52, 53 and 54 which constitute integrated voltage regulators to stabilize the DC voltages of -15 V, + 14 t + 5 V.

FIG. 10 illustrates the control card 23 of the electrode 3 which contains the components already described in
reference to Figures 7 and 8.

Figure II illustrates the analog / digital conversion card 24 (or card A, D, C) which contains the conver
weaver 41 (figure 8) connected by resistors and condensa
teurs indicated on the drawing and by circuit 47 which ensures
the power supply - EV from the -15 V distribution at the various terminals shown in the figure connecting this card 24 to the other cards and to the connectors 26.

We will now describe with reference to FIG. 12, the card 21 of the front face, that is to say of the display of the set values and the display of the different operating states:
The instructions are displayed by two groups 56, 57 of two coding wheels
- a group indicates the aluminum concentration - ::
physical value K = O ... 0.99 mg / l
displayed value KA = 00 .... 99
- a group indicates the capacity of the buffer tank
physical value CB = O ... 9900 L displayed value BA = 00 ... 99
The encoder wheels are read (in decib code decibinary DCE negative logic) by an input port of 1 unit 6, via "3-state" doors 58, 59 (type 74LS244)
These doors are validated when reading the instructions, that is to say once every 24 hours.

The operating states are displayed by two groups 60, 61 of two 7-segment displays, and three indicators 62 (VT) 63 (VR) and 64 (VD)
- a group of displays indicates the% time exceeded (see software) or the electrolysis current IA displayed value of; ; . . 99
displayed current value: 0.0 ... 7.0 A (maximum measurable current)
a group of displays indicates the. '' treatment time (see software) or DA water flow
-displayed value of%: 00 ... 99 SÓ
displayed value of the flow rate: 0.0 ... 8.3 m / h (maximum measurable flow rate)
- the indicator 62 (VT) indicates that the electrolysis current is established (that is to say that the water treatment is carried out).

- light 63 (VR) indicates that the regulation system is late (see software),
- LED 64 (VD) indicates that the regulation system is over (cumulative delay, see software).

 The data is written on the displays 60, 61 in positive logic DCB code, by an output port of the control and calculation unit 6 via registers and decoders 65 to 68 (type 4511). These registers are loaded when writing the statistics or the current and the flow, that is to say once every 24 hours, or during a request. The three LEDs and the decimal point of the displays are controlled respectively by four bits of an output port of the unit 6.

 The commands are carried out by three push buttons 69, 70, 71 - the push button 69 initializes the system, the initialization is automatic when powering up) - the push button 70 causes the weekly statistics to be displayed, - the button push-button 71 causes the display of the electrolysis current and the water flow.

The push button 69 is connected to the initialization inputs of the system circuits. The push buttons 70 and 71 are read respectively by two bits of an input port of the control and calculation unit 6
FIG. 13 shows a card 25 of the control and calculation unit 6, that is to say the card called "microprocessor".

This unit is responsible for regulating and calculating statistics, based on setpoints (aluminum concentration K and capacity of the buffer tank CB) and measurements (water flow D and electrolysis current I), and to display the states on demand.

 It is built around the 72 "UNTEL 8085" microprocessor. To simplify this unit as much as possible, the following structure was used: a programmable peripheral interface 73 of the INTEL 8155 type and a 2 kilo-word memory 74 of the 2716 type which will contain the various programs relating to the operation of the system.

Interface 73 has been chosen for. its great flexibility of use and for its total compatibility with the microprocessor 72. The circuit has
- three programmable input / output ports (PA,
PB, PC) of interface 73 which are used to control the various circuits (control, measuring amplifier and ADC circuit),
- an active memory (RAM) of 256 words which is contained in the interface 73 and makes it possible to store the various data (measurements, results of calculations, counters) as well as the battery of the microprocessor 72,
- a programmable counter 75 which makes it possible, by dividing by 16 the frequency of quartz 76 and an interruption at the processor level, to reduce and synchronize the speed of the computing unit with that of 1 ' electrolysis.

The time base is obtained as follows
The frequency of the clock signal of the microprocessor 72 of 2 MHz (quartz 4 MHz) is divided by 16 by the binary counter 75 (type 74LS93) then by 12500 by a programmable divider (not shown) contained in the interface type 8155) . The resulting 10 Hz signal generates RST 7.5 interrupts of microprocessor 72. The time base, of I s, is obtained by counting these interruptions.

 The read only memory was also chosen for its simplicity of use. Indeed, it requires only one operating voltage (+ 5 V) and can be reprogrammed.

On the other hand, its capacity of 2048 words allows to keep room for later modifications of the programs. Only its addressing requires the use of an address register 77 because the eight low address lines are multiplexed with the eight lines of the data bus of the processor 72. As low address register, a " 8? 12 "classic provided for this purpose.

To control the electrolysis, it is necessary to supply the calculation unit with certain instructions, that is to say the desired alumina concentration and the capacity of ballontampon 2 which is a function of the installation on which is mounts the device. For this purpose, the coding wheels 56, 57 are used which control the "three-state" doors 58, 59. The outputs of these doors will be validated by the processor 72 when reading the instructions and will remain in the "high" state. impedance "during the remainder of the treatment. Similarly, the display of the flow and current measurements, as well as the percentages of treatment and overflow, are displayed.
These display signals are linked to the data bus to be validated by the processor 72.

 To carry out all these validations, an address decoder 78 is used (the "8205") which allows, by decoding the high addresses, to validate all the circuits (read-only memory 74, interface 73, "three-state" doors 58, 59 , percentage, processing and overrun displays) which are thus set up at fixed addresses.

 Note, moreover, the following - the display of the flow rate and the current is done by external control. This display is provided on the treatment percentage displays and requires the decimal point to be switched on, which will be done from a PPI port - the system is initialized on the RESET input (reset ) of processor 72. This initialization takes place automatically during a power failure or must be done manually when the symbols are changed so that the latter are taken into account by 1 control and calculation unit; - the system synchronization signal (I Hz) is obtained from the clock signal of processor 72.

 By tailors, various indications are given below relating to the flow measurement signal, to the memory addresses, to the addresses and assignments of the input / output ports of the microprocessor; '2.

Flow measurement
The frequency signal f provided by the flowmeter generates RST 5.5 interrupts of the microprocessor. the value of the flow is obtained by counting these interruptions during
I s and correction.

Memory addresses
Read only memory 74 OOOOH a 07FFH
RAM 0800H to 08-FFH
Addresses and assignments of entry ports
PORTA - 09H (interface input port A) outputs SO to S7 of the CAN carrying out the current measurement I.

PORTB - CAH (interface output port B) bit Bo: illumination of the VR indicator bit B1: illumination of the VD indicator bit B2: current control I and illumination of the VT indicator bit B3: conversion order of the C.A.N.

bit B4: switching on of the decimal point of the bit-B5 displays: presence of PT processing (not used at output) -.

Programming word for port I / O configuration: 02 H
Destination address: Q8H.

Programming word for starting the divider by 12500 (command 11B) C2H.

Destination address: 08H
PORTC -OBH (interface input port C 73) CO bit: indication of valid converter data 41 bit C1: request to display weekly statistics (BP bit C2: request to display current I and flow D (BP3)
AL - 10H (port of entry) group of coding wheels indicating the aluminum concentration K.

CB = 18H (port of entry) group of coding wheels indicating the capacity of the buffer tank CB.

DEPT = 28H (output port) group of displays indicating the% of time exceeded or current I.

TRAI = 20H (output port) group of displays indicating the% of processing time or flow D.

Programming of interface 73 type 8155
Divider programming mo-ts by 12500 - low part: D4H - high part: 70H
Respective destination addresses - lower part: OCH - upper part: ODH
The programming of the system is illustrated by the general flowchart of figure 14 and the regulation program is represented on figure 15.

 It should be noted that if the flow is very strong, the ideal quantity of electricity requested (which) may be greater than the quantity of electricity injected (gold). In this case, the electrolysis phase takes a "lag" on water consumption. This delay was limited to a higher value (Qbr because If we tried to catch it beyond this value, we would overload with alumina the water stored in the tank. The system will count the volumes of water not treated and we will display the value relative to the total consumption.

In the event of treatment, the program 'imposes a minimum duration of electrolysis without interruption; this can cause negative values of Q = Qj ~ Qr
Below, we will describe the operation of L'ainsi lallation
Operation of the regulation part
Upon start-up, the device performs initialization which consists of - zeroing the working memory - loading the constants from the encoder wheels, - programming the operation of the input-output ports .

The system then waits for interrupts from the flow meter. These interruptions are totaled by a subprogram and define the volume of water flowed.

After one second the system will perform a calculation cycle taking into account the data loaded during initialization, the amount of water flowing since one second as well as the intensity of the current, zero during this first cycle.

If the amount of water flowing during this second is zero, the system decides not to start the treatment and returns to standby for one second.

When there has been a flow during a waiting period, the system finds a deficit in the quantity of electricity during the calculation cycle. It initiates the treatment by switching on the transistor (s) 35 (and 34) and turns on the indicator then returns to standby.

In the following cycles if the deficit, possibly accumulated, remains, the system maintains the processing order and the order of lighting of the delay indicator.

If the cumulative quantity of electricity delivered becomes greater than the necessary quantity calculated from the flow rates, the computer turns off the delay indicator and stops the treatment if the time 9 elapsed since the treatment order is greater than the minimum duration fixed in the program .

Otherwise, it maintains the processing order until this minimum duration and recognizes the resulting excess processing.

During the following cycles, the quantities of electricity required to process the quantities of water flowing are subtracted from this excess.

Treatment will not be triggered again until this excess has been absorbed.

In the particular case where the deficit exceeds a maximum value calculated during initialization from the tank capacities and the alumina rate displayed, a subroutine limits the deficit to this value and lights the overshoot indicator.

These operations will take place regularly until a new initialization order given voluntarily by means of the appropriate button or following a sector interruption.

How the Measurement and Statistics section works
As soon as the initialization is complete, we have the possibility of reading and viewing on the groups of 7-segment displays, the values of the electrode current and the water flow. The current display order requires the processing to start regardless of the regulation decision.

At each cycle the system accumulates in two registers the processing and exceeding states.

Every 24 hours] The percentages of processing time and overrun are carried out by dividing the content of the registers by the number of seconds contained in 24 hours.

These percentages are stored in memory in a stack of 7 pairs of registers according to the 1st input / 1st output principle.

Pressing the statistics button triggers the sequential display of the percentages in processing time and in excess for the past 7 days at any time.

Claims (2)

CLAIMS 1 "- Process for regulating the treatment of water by electrolysis for the protection of sanitary or industrial water distribution networks, according to which a determined quantity of aluminum is introduced into a pipe (l) of the network. depositing by electrolytic dissolving an aluminum electrode 3, inserted in said pipe, in the form of alumina hydrate in the latter, characterized in that it consists in injecting, in a controlled manner, into the electrode (3), an electrolysis current whose intensity corresponds to the dimensions of said electrode, and to regulate the amount of electricity as a function of the flow rate of water circulation and of desired aluminum concentration, said regulation being operated according to an all-urian control of the electrolysis time, 'from a predetermined minimum value. 2 "- Process according to claim 1, characterized in that the actual value of the water flow is measured in the pipeline (l), we After the actual treatment current delivered by the electrode (3) in the form of an amount of electricity, these data are sent together with the set values of the desired concentration of alumina and of the capacity. of a buffer tank (2) mounted in the pipeline and whose capacity is adapted to the flow rate of the latter, has a control and calculation unit (6) which, after comparison with threshold values, controls a modulation of the processing current sent to the 'electrode'. 3 - Installation for implementing the method according to any one of claims 1 and 2, characterized in that it consists of a unit (4) for measuring the flow of water in the pipeline (1), in which is mounted a buffer tank (2) containing an aluminum electrolysis electrode (3), a device (5) for supplying and measuring the treatment current sent to the electro1e (3) and d '' a unit (6) for controlling and calculating the injected treatment current, the output of which is connected to the input of the device (5) for supplying and measuring the current and which comprises three inputs, one of which is connected at the output of the flow measurement unit (4), the second of which receives the set values of the required concentration of alumina and the capacity of the balloon (2) and the third of which receives according to a feedback key (7) the value of the processing current, measured in the supply and measurement device (5). 4 "- Installation according to claim 2, charac terized in that the unit (4) for measuring the flow is constituted by a turbine flowmeter (IO) equipped with an incremental encoder (I2).  50 - Installation according to claim 3, charac  terized in that the incremental encoder (I2) is formed of a  metallized sector disc, driven by the turbine (IO)  and a variable reluctance proximity sensor (I3)  consisting of a transistorized oscillator (I4, I5) and whose  signal is sent to the control and calculation unit (6)  after amplification in a transistor (18) used in am  current threshold plifier and low pass filter and filtering  complementary using a Schmitt rocker (19) raccor  dedicated to a monostable rocker (20) reducing the signal to a  sequence of counted pulses in the control unit (6)  and cal ass  60 - Installation according to any of the reven  dications 3 to 5, characterized in that the device (5)  power supply and processing current measurement includes  a supply circuit connected by a rectifier circuit (30)  to an electrical power supply transformer at  several secondary voltages (28) and comprising a transis  tor (34) supply whose transmitter is connected by a re  adjustable resistance (36) at a first terminal of the rectifier (30)  whose collector is attached to the electrode (3) and whose  base is connected to an output of the control unit (6) and  calculation by 1 intermediate of a control transistor (35) as well as a measurement resistance (37) of low ohmic value  mounted transversely in said supply circuit between  a ground terminal connected to the electrolysis cell of the balloon  (2) and the second rectifier output terminal (30) and of which  the connection end, not grounded, is connected by  1 'through an operational amplifier (40) and a  analog / digital converter (41) to the control and calculation unit (6).  70 - Installation according to claim 6, characterized in that the analog / digital converter is a double ramp integrator.  80 - Installation according to any one of claims 3 to 7 characterized in that the uni-te (6) of regulation and calculation control e-st constituted by a microprocessor (72), a programmable peripheral interface (73 ) including a random access memory storing the various variables and the microprocessor stack 7 a read only memory (74) containing the program, an encoder (78) and an address register (77).  9 - Installation according to claim 8, charac terized in that 1 unit (6) control and 'calculation further contains a time-based circuit comprising a quartz oscillator (76) whose frequency is divided by a counter binary divider (75), itself connected to a programmable divider contained in the interface (73).  IO - Installation according to any one of claims 8 and 9, characterized in that it also includes a display circuit (8, 21) (aluminum concentration and tank capacity) forms, for the various set values by two groups - (56, 57) of encoder wheels connected to input ports of the control and calculation unit (6) by respective "three states" doors (58, 59-) and, for r the display of the different operating states, by two groups (60, 61) of two seven-segment displays (measurable 'maximum current and maximum flow') connected by decoder registers to an output port of the control unit and calculation, and by three LEDs (62, 63, 64) (established electrolysis current VT, delay regulation VR, regulation overflow VD) to another output port of said unit (6).