JPS5962384A - Control device for flow rate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a flow rate control device for an intake flow 6ik in a water purification plant.

[Technical background]

Figure 1 shows the process flow of a typical water treatment plant.

For prefectural water, there is a water intake flow control valve 1, a water intake flow meter (monitoring flow V,
2 in total, 3 landing wells, 4 settling ponds, 1 row, 1 row. j+5
After being treated, the water is stored in a water distribution reservoir 6 and distributed to consumers.

Here, the fund that controls the water flow t11'' is basically:
Since it is necessary to always maintain the water level in the distribution reservoir within a specified value, steps are taken to control the water intake flow ()1 in response to fluctuations in the distribution flow rate.

However, since it takes several hours for the sewage treatment process to reach water intake/distribution/l126, water distribution is not possible. , J 14 changes, if the water intake flow) 11 is changed in response, due to the time delay, r,,, for the fluctuation of the water distribution flow i・1
If this is not possible, there is a possibility that the water level in the water distribution reservoir will exceed the fixed value by +1-1, h+].

So, ff゛>! As shown in Fig. 1 and Fig. 2, r: is water distribution t'lif: 71'j N'l' From the data Qt of 7, a computer calculates the demand and storage of the water distribution flow Jif-8.
4' Q
, l +a+, and the intake flow 1・i corresponding to that value.
A method is used in which the target value i (Q+) is determined, the target value is given to the water intake flow P1 control device 9, and the water intake flow rate control 14 is performed. However, this configuration has the following problems.

In other words, hV7 which basically makes the intake flow rate equal to the water distribution flow rate.
Due to errors in the flow ml meter and water consumed in the process of water intake and distribution, the water intake flow does not necessarily match the water distribution flow FU, and the difference gradually accumulates and eventually reaches the distribution reservoir. There is a possibility that the water level will exceed the specified value. Therefore, the water level of the water distribution reservoir was monitored using the water level gauge 10 of the water distribution reservoir, and it was found that the water level of the water distribution reservoir was likely to exceed the fixed value (Ninohe's "Water intake flow 1 determined from the special distribution water flow 16 predicted value 11" fi4 target value Q
The value obtained by adding the correction value (α) 13 to +1 is Iy water flow f9.
It is necessary to set the L control target value, and even in that case, there is a risk that the water level in the water distribution reservoir will exceed the specified value.

Furthermore, if we try to make water distribution flow rate = water intake flow rate, then water distribution flow)T
1 constantly changes, the water intake flow rate must also constantly change, and the frequency of opening and closing of the water intake flow control valve 1 increases.
This is undesirable because it causes constant fluctuations in the water treatment process.

[Purpose of the invention]

The purpose of the present invention is to determine the target water intake flow rate not from the water distribution flow rate but from the water level of the water distribution reservoir, so that the water level of the water distribution reservoir can always be kept within the specified value, and
It is an object of the present invention to provide a flow control device that can extremely reduce the frequency of opening and closing of a water intake flow control valve and reduce fluctuations in the water treatment process.

[Invention Fence Key]

The present invention includes a control valve that adjusts the water intake flow rate, a water intake flowmeter that measures the water intake flow rate regulated by the control valve, a water level meter that measures the water level of a water distribution reservoir, and a water level meter that measures the pH 4 of effluent distributed from the water distribution reservoir. A flow rate control device (-) consisting of a water distribution flow 4jt #j, which has a function of determining whether the water level of the distribution reservoir is at a predetermined average water level, and a function of determining whether the water level of the distribution reservoir is at a predetermined average water level, and
A function to calculate the predicted amount of water distribution flow based on two functions, a function to simulate the water level fluctuation of the distribution reservoir by changing the water intake flow rate, and a function to determine whether the water level of the distribution reservoir is within a predetermined fluctuation regulation value by this simulation. function and
A function to change the water intake flow rate based on this determination result, and m-t to determine whether the water intake flow rate has been changed by this function.
This is a flow rate control device that has a function of instructing the water intake flow rate to be changed to keep the water level fluctuation in the water distribution reservoir within a specified value based on the determination result.

That is, in the water intake flow rate control of the v-r water purification plant of the present invention, a water level fluctuation simulation of the distribution reservoir is performed based on the demand prediction calculation result of the distribution flow 11, and as a result, if the water level of the distribution reservoir exceeds the upper and lower limit specified values, , re-simulate water distribution reservoir water level change jf7H when increasing/decreasing water intake flow 111, find water intake flow 54 target value that keeps the water level fluctuation in the distribution reservoir within the specified value, and calculate the target value to This is a flow control device for a water treatment plant, which is characterized by controlling the flow rate of water intake.

Since the present invention is configured as described above, it is possible to control the water level of the water distribution reservoir to always keep it within the lower limit range for processes that have a time delay in the water treatment process, such as water intake flow rate control at a water treatment plant. 1J, (intake flow i'i) (The target value is changed when the water level in the distribution reservoir reaches the average water level, and the daily water level fluctuation is only a maximum of 4 changes per day Q (intake flow fA). :
The frequency of opening and closing of the control valve can be extremely reduced, and the water treatment
．． ! The effect is that it is possible to reduce the fluctuations imparted to the lj process.

[Embodiments of the invention]

Next, the present invention will be explained in detail. ? wa71nro;J:i
-τ(water flow (■); a water intake flow meter 2 that measures the intake flow rate regulated by the A!I'l1 control valve 1; and a water level meter 10 that measures the water level of the water distribution reservoir 6. , the water distribution flow totaling 1111+ water jl distributed from the water distribution reservoir 6.
] In a flow 4d control device consisting of a total of 7 functions, the function 21 determines whether or not the water level of the distribution reservoir 6 is at a predetermined average water level. 1)
A function 22 that calculates the predicted soil of water intake flow F11, a function 23 that simulates the water level fluctuation of water distribution reservoir 6, and a function 23 that simulates the water level fluctuation of water distribution reservoir 6 by this simulation. a function 24 for determining whether or not the fluctuation is within a prescribed value; a function 25 for changing the water intake flow rate based on this determination result; a function 26 for determining whether the water intake flow rate has been changed by this function; The figure shows a flow rate control device having a function 27 for instructing the water intake meteor to change the water level in the water distribution reservoir 6 to keep it within a specified value based on the result.

Fluctuations in the water distribution flow rate during a day at a water treatment plant basically show a trend as shown in Figure 3. Figure 3 shows the distribution flow rate prediction curve determined by the predictive meter. When this water distribution flow 1 simulates the water level fluctuation in the distribution reservoir when the intake flow rate is constant with respect to the predicted curve, a fluctuation curve as shown in FIG. 4 is obtained.

In the present invention, based on the predicted value of the water distribution chamber, a simulation of future fluctuations in the water level of the water distribution reservoir is performed, and if it is determined that the simulation result exceeds the specified value of the water level of the water distribution reservoir by 17i, the water intake (] The purpose is to re-simulate the fluctuation of water level in the water distribution reservoir when changing water level 1, find a water intake 11 target value at which the water level in the water distribution reservoir falls within the specified value, and perform water intake control based on this target value.

In the simulation curve of water level fluctuations in the distribution reservoir shown in Figure 5, the time at which the simulation is performed is such that the daily distribution reservoir water level fluctuation curve basically consists of two peaks and valleys as shown in Figure 4. This is done when the average water level of the distribution reservoir reaches the lower limit water level.

For example, based on the predicted value of water distribution flow l after 1:00 at time 11, we simulated the fluctuation of the water level at 11:00+2+ after 11:00 when the current water intake flow rate was maintained, and the result is shown by the solid line. If this is obtained, it can be determined that the water level in the water distribution reservoir will be below the upper limit water level, so in this case, the water intake Meteor will maintain the current flow rate. Next, at time t when the average water level has been reached, a simulation of fluctuations in the water level of the water distribution reservoir after 12:00 is similarly performed. In this case, if the simulation result is determined to exceed the lower limit water level as shown by solid lines 1 and 1, re-simulating the fluctuations in the water distribution reservoir water level when the water intake flow rate is increased is performed at one point on the 8Ii line. , 2 until a water intake flow rate that falls within the lower limit water level is determined, and the water intake flow is controlled based on the water intake flow rate target value 17 and water intake flow rate control. Figure 5 shows changes in the target water intake flow rate. At time t, it was determined that there was no need to change the water collection flow chamber as described above, so the previous value Q++ shown in the solid line was held, and at time t2, as described above (2) If Ql+ is maintained, the water level in the distribution reservoir will be exceeded, so use the method described above to find the intake flow-target value that is within the lower limit water level, that is, the value Qh shown at one point on the octopus line.
Change it to that value.

After that, similarly, when the average water level is reached, the target water intake flow rate is determined using the above procedure. FIG. 7 shows the above move 11ji.

[Brief explanation of the drawing]

Figure 1 is a process diagram showing a typical water treatment plant process;
The figure is a flowchart diagram showing conventional water intake flow control, Figure 3 is an explanatory diagram of typical daily fluctuations in water distribution flow, and Figure 4 is the water level in the distribution reservoir when the intake flow is constant. Fig. 6 is an explanatory diagram showing typical daily fluctuations in the water distribution reservoir water level when the water intake flow rate is constant and when the water intake flow rate is changed according to the present invention. is the water intake flow according to the present invention t! - An explanatory diagram showing fluctuations in target values, Figure $7 is a flowchart diagram showing an example of the present invention. 1... Control valve 2... Water intake flow meter 3...
Landing well 4...Sedimentation pond 5...Filtration pond
6...Water reservoir 7...Water flow 61 total 8.
・Demand forecast calculation 9...Rusha control system (d 10...
・Reservoir water level gauge (7317) Agent Patent attorney a
ll near 7. H Yu (1 idiot) Figure 1 Figure 2 Figure 3 Figure 4 River - Width, ;zzu4 Figure 5 1 Yu 2 Figure 6 - Time

Claims (1)

[Claims] Adjust the water intake flow meter? Jtt1 control valve, a water intake flow meter that measures the water collection flow box adjusted by this control valve, a water level meter that measures the water level of the water distribution reservoir, and a water distribution flow meter that measures the water volume distributed from the water distribution reservoir. A flow FB4 control device comprising: a first determination function for determining whether or not the water level of the water distribution reservoir is at a predetermined average water level; A calculation function that calculates R, and a simulation chamber that simulates water level fluctuations in the distribution reservoir by changing the intake flow rate;! function, a second determination function that determines whether the water level of the water distribution reservoir is within a predetermined variable marriage 1 constant value by this simulation calculation, and a second determination function that determines whether or not the water level of the water distribution reservoir is within a predetermined value. 1! Changes 1j, , lj to A, a third determination function that determines whether intake flow 1, Y has been bent or not due to this change 141, and this ゛('1 (separate conclusion - Check the water level fluctuation of the water pond (11 times within the list price)
A flow rate control device comprising a command function for commanding water flow to vary slightly.