SU791627A1 - Method of control of water preparation for filtration - Google Patents

Description

The invention relates to the field of automation of production processes and can be used in water filtration processes.

A known method of regulating the process of preparing water for filtration. consisting in changing the flow rate of the coagulant into the treated water, depending on the flow rate and electrical conductivity of the water after mixing with the coagulant \ 1J.

The known method has limited possibilities with respect to the accuracy of maintaining the pH value, since a change in the electrical conductivity of water in the general case does not uniquely characterize a change in the pH value of a zoda.

The closest known method is a method for controlling 20 irrgesses of preparing water for filtration, which consists in changing the flow rate of alkali solution in the treated water depending on the flow rate and on the pH of the treated water 25 to the point of introduction of the coagulant, changing the flow rate of the coagulant in the process water when it is introduced after the injection site of the alkali solution along the water, depending on the flow rate of water A A} 30

The known method when used to regulate the process of preparing water for filtration has the disadvantage of reduced accuracy in maintaining the pH of the treated water for the following reasons.

According to the operating conditions, the place of installation of the pH-value sensor can be chosen after the place of introduction of the alkali solution into the water, but to the place of introduction of the coagulant solution, otherwise the sensor may lose operability.

However, the coagulant solution changes the pH of the water entering the filtration. At the same time, in order to maintain an optimal water filtration regime, stabilization of the pH value with a given accuracy is necessary.

Particularly large errors in pH can occur when the concentration of the coagulant solution changes.

The aim of the invention is to increase the accuracy of regulation.

For this, alkali consumption is additionally adjusted depending on the consumption of 100% coagulant, i.e. in 3 hours 4. -V '791627 depending on the product of the consumption of the coagulant on its concentration.

The drawing shows a block diagram of a control system that implements the described method.

The alkali solution is mixed with the source water from the tank 1, the coagulant solution is mixed from the tank 2. The flow rate of the source water is measured using a flow sensor 3 depending on the signal from which the metering pump 5 is used to regulate 4, maintaining a constant flow ratio water and alkali solution. Feedback from the metering pump 5 (by the number of strokes of the plunger) is fed to the input of the controller 4.

According to the signal from the sensor 3, the water flow with the help of the regulator 6 acts on the pump-doeator.or 7, maintaining a constant ratio of water flow to the coagulant solution. Feedback from the metering pump 7 (according to the number of plunger strokes) is received. At the input of the regulator 6.

After the place of introduction of the alkali solution into the water, but before the place of introduction of the coagulant into the water, the pH of the water is measured using a sensor 8 and adjusted using the controller 9, changing the task of the controller 4.

In the tank 2, using the sensor 10, the concentration of the coagulant in its solution is determined, then, according to the signals from the sensor 10 and the metering pump 7, the weight flow rate of 100% of the coagulant to water is determined using function block 11, the signal from the functional block 11 is fed to the controller 4 through the correction block 12.

In addition, the signal from the coagulant concentration sensor 10 is supplied to the regulator 6 to correct the performance of the metering pump 7 depending on the concentration of the coagulant in the tank 2.

necessary for optimal filtering performance of the system for changing the water return due to variations in the calculation of the weight flow rate of 100% of the coagulant when changing the flow rate of the alkali solution, it is possible to maintain the specified pH value after the place of introduction of the coagulant solution into the water along the water, the laziness mode.

If the center of coagulant in it is compensated by a change in the flow rate of the alkali solution.

Using the described method will improve the accuracy of regulating the pH of the water prepared for filtration and optimizes the coagulation process.

Claims (1)

Claim VNIIIPI Order 9374/18 Circulation 1020 The method of regulating the process of preparing water for filtration by changing the flow rate of alkali solution in the treated water depending on the flow rate of water and on the pH value of the treated water to the place of introduction of the coagulant, as well as changing the flow rate of coagulant into the treated water after the place of injection of the alkali solution along the water, depending on water consumption and coagulant concentration, characterized in that, in order to increase the accuracy of regulation, when changing the flow rate of alkali solution, a correction for the consumption of 100% coagulant is introduced.