JPS6361803A - Make-up water facility device - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a make-up water equipment device that supplies make-up water to a plurality of loads using a plurality of make-up water pumps.

(Prior Art) Generally, in conventional make-up water equipment, the load amount, that is, the make-up water pump discharge port is detected based on the discharge side pressure of the make-up water pump, and the make-up water pump is operated according to the load amount.

FIG. 4 shows an example of a conventional make-up water equipment, in which water is supplied to each load 3 by three make-up water pumps 2 using a tank 1 as a water source. Each load 3 is divided into several groups, and a flow meter 4 for measuring the amount of makeup water for each group is provided for each group.

The reason why the flow rate is measured in several groups in this manner is that the flow rate range in the make-up water pump discharge main pipe 5 is large, and the error in flow rate measurement in this main pipe 5 becomes large.

On the other hand, one make-up water pump 2 is normally operated continuously, and when a pressure detector (PS) 6 detects a pressure drop in the make-up water pump discharge main pipe 5 due to an increase in the load amount of the load 3, the second make-up water pump 2 is operated continuously. Makeup water pump 2 starts automatically.

At this time, the pressure in the make-up water pump discharge main pipe 5 recovers, but if the load increases further, the pressure drop in the make-up water pump discharge main pipe 5 is detected by the pressure detector 6, and the third The make-up water pump 2 is configured to automatically start.

As described above, in the make-up water equipment device in which the make-up water pump 2 is controlled by the pressure of the pressure detector 6 provided on the make-up water pump discharge side, the following problems occur.

The pressure change in the make-up water pump discharge main pipe 5 is caused by not only the total lift of the make-up water pump 2 but also the tank 1 that is the water source.
water level is included. In other words, when the second and third make-up water pumps 2 start automatically, the operating points of the make-up water pumps 2 that are already in operation will vary between the minimum water level 8 and the maximum water level (overflow water level) 9 of the tank water level. It will change within a range approximately equal to the width 7. □ In general, the pressure setting value P of the pressure detector 6 for automatically starting the second and third make-up water pumps 2 is based on the assumption that the water level of the tank 1 is the lowest water level 8, and this water level 8 and the pressure detection Vessel 6
The value is calculated by adding the rated total head H2 of the make-up water pump to the static head difference H1 of the installation height of When this happens, the second or third make-up water pump 2 will automatically start.

Now, if the water level of the tank 1 is the overflow water level 9, in order for the make-up water pump 2 that is on standby to start automatically due to the increase in load, the make-up water pump 2 that is already in operation must be at the minimum water level of the tank 1 8. and water level fluctuation width 7 of overflow water level 9
This results in overflow operation equivalent to . To further explain this using the Q-H curve of the make-up water pump 2 in Figure 5, when the make-up water pump 2 that is on standby automatically starts, the operating range of the make-up water pump 2 that is already in operation is the rated point. It is between point A and point B of . The make-up water pump total head difference between points A and B (corresponds to the water level fluctuation range 7 of the tank 1 shown in FIG. 4).

For this reason, the performance characteristics of the make-up water pump 2 need to take into account the water level fluctuations in the tank 1. In particular, when the tank 1 with a large water level fluctuation width 7 is used as the water source, the overload of the make-up water pump 2 must be considered. It is necessary to expand the flow rate operation range or to use a make-up water pump 2 whose total head changes significantly in response to changes in discharge flow rate.

However, this causes various problems such as an increase in pump motor output, an increase in fluctuations in make-up water pressure, and an increase in the maximum operating pressure of the equipment.

Note that in order to avoid being affected by water level fluctuations in the tank 1, it is possible to control the make-up water pump 2 using only the pressure difference before and after the make-up water pump 2, that is, the total lift of the make-up water pump 2; In this case, the following problems occur.

FIG. 6 shows a QH curve for each number of makeup water pumps 2 in operation. From this figure, as the number of vehicles in operation increases, the QH curve becomes more linear. In other words,
Changes in total head due to changes in flow rate are reduced. This means that if the make-up water pump 2 is controlled using changes in the pressure at the discharge outlet, it will be greatly influenced by the instrument error of the pressure detector 6.

All three make-up water pumps 2 are now in operation, and if the flow rate at this time is 0 point, the total head will be point D. At this time,
If the pressure detector 6 detects the total head of the makeup water pump 2 as 5 points due to the instrument error e of the pressure detector 6, it is determined that the load amount has been reduced, and one of the three makeup water pumps 2 is activated. It will be automatically stopped. However, since the load amount is not actually reduced, the operating point changes toward point F so that the two make-up water pumps 2 replenish the same amount. Then,
The pressure detector 6 will detect the pressure drop and will restart the make-up water pump 2, which was previously stopped. Moreover, this phenomenon is repeated.

If the above-mentioned phenomenon is repeated, it becomes a cause of problems such as an adverse effect on the pump prime mover, an increase in running costs, and fluctuations in make-up water pressure.

Therefore, as a countermeasure against this problem, it is considered that the setting value of the pressure detector 6 should be determined in advance by considering the instrument error, but as shown in Fig. 6, the Q
- If the H curve is linear, there is a problem in that it is impossible to even take into account instrument errors.

For the reasons described above, many make-up water facilities have been proposed in which the make-up water pump is automatically controlled only at startup, and the make-up water pump is manually controlled at the operator's discretion when the make-up water pump is stopped.

(Problems to be Solved by the Invention) The present invention was made in view of the above circumstances, and its purpose is to be able to plan the performance characteristics of the make-up water pump without considering water level fluctuations in the water source tank, and to adjust the load amount accordingly. It is an object of the present invention to provide a make-up water equipment device that can automatically operate an appropriate number of make-up water pumps according to the demand and can supply make-up water at a stable pressure.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a make-up water equipment device that supplies water from a plurality of make-up water pumps to a plurality of loads via a main pipe. A flow meter that divides the plurality of loads into a plurality of groups and measures the flow rate of water supply flowing into the total loads, and a control device that controls the number of operating makeup water pumps according to the output value from the flow meter. It is characterized by the following.

(Function) According to the make-up water equipment device of the present invention, even if the amount and frequency of use of make-up water differs for each load, the make-up water pump is automatically started and stopped in accordance with the total load amount. It is possible to supply make-up water at a stable pressure.

(Example) Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic system diagram of an embodiment of the present invention.
Components that are the same as those in FIG. 4 already explained are given the same reference numerals, and detailed explanation thereof will be omitted. In the figure, water is supplied to each load 3 via a make-up water pump discharge main pipe 5 by three make-up water pumps 2 using a tank 1 as a water source.

Each load 3 is divided into several groups, and the amount of make-up water for each group is measured by a flow meter 4 installed for each group.

The flow rate measurement values from each flowmeter 4 are input into the flow instructions 11. The output of the flow rate indicator 11 is input to the control circuit 12. The control circuit 12 controls starting and stopping of the make-up water pump 2. Note that the flow rate indicator 11 and WJ control device 12 are housed within the central control i10.

Next, the operation of this embodiment will be explained.

In an atomic h-plant, the amount of water flowing into the plant and the amount of water flowing out of the plant are measured in order to manage the water balance within the plant. Replenishment water equipment also measures the amount of replenishment. On the other hand, each load 3 has a different load amount and load frequency, and the amount of makeup water sometimes varies within a larger range.

Therefore, the amount of make-up water is not measured at the make-up water pump discharge main pipe 5, but is measured for each of several load groups in order to reduce measurement errors. In addition, in consideration of reducing radiation exposure of workers, the system is configured such that the flow rate for each group can be checked using a flow meter 11 in the central control station 10, without checking the flow rate on site.

The flow rate at this time may be output as an integrated flow.

In this embodiment, the control device 12 detects the sum of the measured values of these flowmeters 4 as the instantaneous flow ff1QΣ, and selects the number of operating make-up water pumps 2 suitable for the flow rate QΣ at that time.
controlled by

FIG. 2 shows an example of control by this control device 12 at 70-diameter. In the same figure, the make-up water pump 201 is now
Assume that the room capacity per unit is 50 m3/h. Initially, the total amount of load QΣ measured by each flowmeter was 20m3
/h. At this time, only one make-up water pump 2 remains in operation. After that, as the load increases, the total load QΣ
When the water exceeds 50 m3/h, the second make-up water pump 2 is automatically started.

Roughly speaking, the load amount increases and the total load amount QΣ becomes 100m3/
When h is exceeded, the third make-up water pump 2 is automatically started. After that, when the total load QΣ reaches 80 m3/h, one of the three make-up water pumps is automatically stopped.

In this way, the makeup water pumps 2 are automatically started and stopped based on the relationship between the number of makeup water pumps 2 in operation and the load amount.

In addition, by being able to automatically stop the make-up water pump as described above, the rotation of the make-up water pump to be stopped can be changed to, for example, "A pump running - load increase - B pump starting - load decrease - A pump stopping". If this is done, it will be possible to automatically equalize the operating time of each make-up water pump.

FIG. 3 shows a schematic system diagram of another embodiment of the present invention, and the same components as in the above embodiment are given the same reference numerals, and detailed explanation thereof will be omitted.

As shown in the figure, if a flow meter 13 for controlling the make-up water pump 2 is installed in the make-up water pump discharge main pipe 5 and the control is performed according to the flowchart shown in FIG. The make-up water pump 2 can be automatically started and stopped. In this case, the flow meter 13 may consider the range ability in the range related to the control of the makeup water pump 2 without considering the range ability in the entire range of makeup water amount. For example, make-up water pump 2
is 50m3/hx3 units, approximately 50-100m3
It is only necessary to have a range ability of /h.

[Effects of the Invention] As explained above, according to the make-up water equipment device of the present invention, the performance characteristics of the make-up water pump can be planned without considering water level fluctuations in the water source tank. The pump can be started and stopped automatically, and make-up water at a stable pressure can be supplied. In addition, since the pump is controlled by the discharge flow rate of the make-up water pump, there is a large margin of error at the control point, that is, the set point for starting and stopping the pump, which makes it difficult to design with flexibility. It has excellent effects.

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[Brief explanation of drawings]

FIG. 1 is a schematic system diagram of one embodiment of the present invention, FIG. 2 is a flowchart showing an example of control according to the present invention, FIG. 3 is a schematic system diagram of another embodiment of the present invention, and FIG. 4 is a conventional system diagram. The schematic system diagrams of the make-up water equipment, FIGS. 5 and 6, do not show part of the performance of the make-up water pump, but are diagrams showing the Q-11 curve. 1... Tank 2... Make-up water pump 3.
...Load 4...Flowmeter 5...Makeup water pump discharge main pipe 6--Pressure detector 7...Tank water level fluctuation range 8...Tank minimum water level 9...Tank overflow water level 10... ...Central control 11...Flow rate indicator 12...Control device 13
...Flowmeter (8733) Agent Patent Attorney Yoshiaki Inomata (Baka 1
Name) Tυ Figure 1 Figure 2 Figure 3 Figure 4 Tunuko (Q) Figure 5 Figure 6

Claims (3)

[Claims] (1) In a make-up water equipment device that supplies water from a plurality of make-up water pumps to a plurality of loads via a main pipe, the plurality of loads are divided into a plurality of groups, and the flow rate for measuring the water supply flow rate flowing into all the loads. 1. A make-up water equipment device comprising: a flow meter; and a control device for controlling the number of operated make-up water pumps according to an output value from the flow meter. (2) The make-up water equipment device according to claim 1, wherein the flow rate of the water supply flowing into the entire load is the total value of the output values of flow meters installed for each group. (3) The make-up water equipment device according to claim 1, wherein the flow rate of the water supply flowing into the full load is an output value of a flow meter installed in the main pipe.