JP5492459B2 - Pressure control device and pressure control method in water distribution network - Google Patents

Description

  The present invention relates to a pressure control device and a pressure control method in a distribution network that suppresses pressure fluctuations from a distribution reservoir to a distribution network that supplies water to consumers.

  As described in [Patent Document 1], in the conventional technology, a distribution network that supplies water to consumers from a distribution reservoir is different from a distribution facility A that has a variable speed pump and a return valve installed in parallel with the variable speed pump. In order to prevent pump cavitation when the pump discharge flow rate decreases at midnight etc. in the distribution network to which the distribution facility B, for example, the distribution facility B is connected, and the distribution facility A needs to distribute water below the minimum rotation speed operation range. The pump is continuously operated by continuing the water distribution while returning the water to the pump well by opening the return valve.

JP-A-2-98712

  As shown in FIG. 3, a water distribution facility A having a variable speed pump and a return valve installed in parallel with the variable speed pump is installed in a distribution network that supplies clean water from a distribution reservoir to consumers. In a distribution network to which another distribution facility, for example, distribution facility B is connected, if the indentation pressure from distribution facility B is large, the pipe loss of distribution facility A increases and the distribution pressure rises. Operates in a direction to reduce the rotational speed. As a result, as shown in FIG. 4, the pump whose rotational speed has decreased to the minimum rotational speed causes pump stop due to no water supply due to a decrease in the water distribution flow rate, and the pressure in the pipe changes suddenly, causing turbid water generation. For this reason, when it is expected that no water will be delivered due to the indentation pressure from other water distribution facilities, all pumps will be stopped and water will be distributed to customers using other water distribution facilities. It is necessary to continue the plant monitoring until the operator is burdened. Further, when all the units are stopped in advance, the pressure fluctuation of the water distribution network is unavoidable because the pump reaches a sudden stop from the region where the pump speed is high.

  An object of the present invention is to provide a pressure control device and a pressure control method in a water distribution network that can stop all pumps without giving pressure fluctuations to the water distribution network.

  In order to achieve the above object, the present invention provides a variable speed pump in a water distribution facility in which a return valve having a plurality of pumps and a flow control device is provided in parallel in a water distribution network that supplies clean water from a distribution reservoir to consumers. Pressure controller that controls the pressure to the target pressure, a judgment device that detects the push-in state of the other water distribution equipment from the actual water flow rate and actual water distribution pressure, and determines the stop timing of all units from the pump rotation speed, and a series of return valve opening and closing operations And an opening degree regulator that determines the opening and closing timing from the return flow rate, and suppresses pressure fluctuations that occur when all pumps of the self-distribution equipment are stopped.

  According to the present invention, it is possible to stop all pumps without giving a pressure fluctuation to the water distribution network by determining the push-in state and controlling the opening degree of the return valve before stopping the pump non-water supply.

It is a block diagram of the pressure control apparatus which is one Example of this invention. It is a figure explaining the operation | movement at the time of the pump stand stop of a pressure control apparatus. It is the schematic of the indentation pressure avoidance by a return valve. It is the schematic of the pressure change phenomenon at the time of the pressure fluctuation phenomenon at the time of the conventional pump stoppage, and suppression measures.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a pressure control device according to the present embodiment.

In the first water distribution facility of the present embodiment, a plurality of variable speed pumps P _{1 to} P _n are installed in a distribution network that supplies clean water from the pump well 13 to the customer 14, and the variable speed pumps P _{1 to} P _n A return valve 15 is installed in parallel. Apart from the first water distribution facility, a second water distribution facility (not shown) is connected to the water distribution network.

  The pressure control device 1 is provided with a water distribution pressure setting device 2, and a pressure controller 10 for controlling the variable speed driving device 11 of the pump so as to be a target pressure set by the water distribution pressure setting device 2. ing. The water pressure CP detected by the water pressure gauge 17 is fed back to the pressure controller 10.

  Further, a pump specified rotation speed setting device 3, a water distribution flow rate specified value setting device 4, and a water distribution pressure specified value setting device 5 are provided, and are connected to the pump all-stop-time determination device 8, respectively. A return well target opening setting device 6 and a return water flow rate integration setting device 7 are provided and connected to a return valve opening controller 9. The return valve opening controller 9 is connected to the return valve 15 via the valve opening / closing device 12. In the pump specified rotation speed setting device 3, a specified rotation speed NL is set, in the distribution flow rate specified value setting device 4, a specified flow rate FL is set, and in the distribution pressure specified value setting device 5, a specified pressure PH is set. In the return well target opening setting device 6, the target opening Z1 of the return valve 15 is set, and in the returning water flow rate integration setting device 7, the return flow integrated value Q is set.

The pump stop time determination unit 8 includes a pump rotation number N detected by a pump rotation number detector 19 provided in the variable speed pumps P _{1 to} P _n , a distribution pressure CP detected by a distribution pressure gauge 17, The distribution flow CF detected by the distribution flow meter 18 is fed back, and the pump stop timing determination unit 8 is connected to the return valve opening controller 9.

  When a plurality of water distribution facilities are connected to the water distribution network and the water distribution facility is operated at the minimum number of revolutions with one pump during a time period when the demand for water supply decreases at midnight, etc., another second The pumping pressure from the water distribution equipment causes non-feeding water by pushing near the discharge side of the water distribution equipment, so it is necessary to stop all pumps. In order to suppress pressure fluctuations that occur when all the pumps are stopped, the piping 20 having the return valve 15 is installed in parallel with the pump, and the return valve 15 is opened before no water is supplied, so that the first water distribution The pressure fluctuation to the water distribution network is suppressed by stopping all the pumps while letting both the discharge pressure of the facility and the pushing pressure of the second water distribution facility to the pump well 13.

  In order to detect the push-in state, the pump all-stop-time determination unit 8 detects the specified flow rate FL input from the distribution flow rate specified value setting unit 4, the specified pressure PH input from the distribution pressure specified value setter 5, and the pump specified rotation. Based on the specified rotational speed NL input from the number setting device 3, the pump stop time of all pumps is determined.

  The pump all-stop-time determination unit 8 calculates Formulas 1 to 3 from the input distribution pressure CP, the distribution flow rate CF, and the pump rotational speed N. As shown at time t1 in FIG. When 2 is satisfied, it is determined that the water distribution pressure has risen despite the fact that the water distribution flow rate has not come out, and that the push-in state is satisfied, and before the pump reaches the minimum rotation speed region Nmin by satisfying Equation 3. It is determined that the pump is stopped.

[Equation 1]
Distribution pressure CP> regulated pressure PH (1)
[Equation 2]
Water distribution flow CF <regulated flow FL (2)
[Equation 3]
Pump rotational speed N <specified rotational speed NL (3)

  The return valve opening controller 9 determines the opening / closing operation and opening / closing timing of the return valve 15 based on this determination, and the target opening Z1 of the return valve 15 set by the return valve opening controller 9 and the return water flow rate. Control is performed so that the return flow rate integrated value Q set by the integration setting unit 7 is obtained.

  For example, as shown at time t2 in FIG. 2, the pump stop timing determination unit 8 outputs the determination result to the return valve opening controller 9 as a return valve operation command, and the return valve opening controller 9 The opening / closing device 12 is controlled to open the return valve 15 to the target opening Z1.

  At this time, a constant change width ΔMV and a constant period Δt are set so as not to give control disturbance such as hunting to the pressure fluctuation to the water distribution network and the pressure control of other water distribution facilities, and the output value of the return valve opening CZ A certain MV is calculated by Equation 4. The calculation execution cycle of Equation 4 is Δt, and the calculation is executed until SV = MVn.

[Equation 4]
MVn = MV _n-1 + ΔMV (4)

  In order to prevent disturbances and turbid water in the pressure control of other water distribution facilities, and to reduce the change width ΔMV so as not to give a pressure burden to the piping, and lengthen the calculation execution period Δt, The pushing pressure can be returned to the pump well 13 through the return pipe without giving a burden.

  Since the water quality in the return pipe 20 has deteriorated due to staying for a long time, the return water flow rate integration CQ is set by the return water flow rate integration setting unit 7 so as to minimize the amount of water returned to the pump well 13. The indentation pressure is returned to the target value Q. When the target value Q is reached at time t3, the return valve opening degree controller 9 notifies the operator that all pumps can be stopped.

  After all the pumps are stopped, water is supplied to the customer from the water distribution facility B. Therefore, the return valve opening controller 9 immediately closes at time t4. If the return valve is rapidly closed at this time, it causes a pressure fluctuation to the consumer. Therefore, the return valve is gradually closed with a change width and a calculation cycle expressed by Equation 4.

  According to the present embodiment, it is possible to stop all pumps without giving pressure fluctuation to the water distribution network by judging the pushing state and performing the opening control of the return valve as shown in Equation 4 before stopping pump non-water supply. It becomes. As a result, it is possible to minimize the pressure burden on the rapid control fluctuations and aging pipes to other water distribution facilities, so that generation of muddy water such as red water can be prevented.

DESCRIPTION OF SYMBOLS 1 Pressure control device 2 Distribution pressure setting device 3 Pump specification rotation speed setting device 4 Distribution flow specification value setting device 5 Distribution pressure specification value setting device 6 Return well target opening setting device 7 Return water flow rate integration setting device 8 Stop all pumps Timing determiner 9 Return valve opening controller 10 Pressure controller 11 Variable speed drive device 12 Valve opening / closing device 13 Pump well 14 Customer

Claims (3)

A first water distribution facility having a variable speed pump and a return valve installed in parallel with the variable speed pump in a distribution network for supplying tap water to consumers from the distribution reservoir;
And a separate second water distribution facilities connected to the first water distribution facilities, determined by the pump total base stop timing determination unit, the detected distributed water flow, water distribution pressure, the total base termination timing pump from the pump speed Based on the determination result, the return valve opening controller opens the return valve before the non-water supply is performed, and the discharge pressure of the first water distribution facility and the pushing pressure of the second water distribution facility are released to the pump well. The pressure control method in the distribution network which suppresses the distribution pressure fluctuation to the consumer.   In order to suppress the pressure fluctuation to the customer, the return valve is opened with a constant change width and a constant cycle. After the pump is stopped, the return valve is closed to supply the customer from the second water distribution facility. The pressure control method in the water distribution network according to claim 1 to be operated. A first water distribution facility having a variable speed pump and a return valve installed in parallel with the variable speed pump in a distribution network for supplying tap water to consumers from the distribution reservoir;
And a separate second water distribution facilities connected to the first water distribution facilities, and detected distributed water flow, water distribution pressure, pumps Full pedestal termination timing determining pumps Full platform termination timing from the pump rotational speed determiner ,
The return valve is opened before the non-water supply from the determination result of the pump stoppage time determining unit so that the discharge pressure of the first water distribution facility and the pushing pressure of the second water distribution facility are released to the pump well. The pressure control apparatus in the water distribution network provided with the return valve opening degree controller which controls to.

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