JPH0733889B2 - Water supply pump outlet valve control device - Google Patents

Description

The present invention relates to a water supply pump outlet valve control device having a function of protecting a water supply pump outlet water supply pipe in a thermal power plant or the like.

(Prior Art) The recent thermal power plant, as the nuclear power plant has been operated as a base load,
In many cases, a variable pressure operation method that changes the main steam pressure according to the operating load is adopted in order to respond quickly to changes in power supply and demand, shorten the plant startup time, or improve efficiency in the partial load range.

In this variable-power-type thermal power plant, it is common to install a feed water pump outlet feed water control valve, which is used only when the plant is started and when the load is low, on the feed water pipe of the turbine driven water feed pump.

This is because the boiler is often in a non-pressurized state when the plant is started, and the required feed water flow rate at the time of ignition of the boiler is small (the minimum flow of the boiler is usually about 25% of the maximum continuous evaporation of the boiler). ), On the other hand, due to its characteristics, the water supply pump has a high gain in the low flow rate region, and the water supply flow rate changes greatly even with a slight change in the rotational speed of the drive turbine, so a water supply pump outlet water supply control valve is provided, This is because the water supply pump is held at a constant number of revolutions and the water supply flow rate is adjusted by controlling the opening degree of the water supply pump outlet water supply control valve to improve the controllability of water supply in the low flow rate region. In this case, the main steam pressure also rises in the high load basin, the differential pressure across the feed water pump outlet feed water control valve also increases, and it is technically difficult to deal with such problems as pressure resistance and erosion of the valve. Therefore, the water supply pump outlet water supply control valve is not used in the high load region, and the water supply flow rate is adjusted by controlling the rotation speed of the water supply pump driving turbine.

FIG. 3 shows a schematic configuration of the feed water flow rate control device in the plant having the feed water pump outlet feed water regulating valve whose use is limited only when the plant is started and when the load is low as described above. A check valve 3, a water supply pump outlet water supply control valve 4, and a water supply pump outlet water supply control valve rear valve 5 are inserted in the water supply pump outlet water supply pipe 2 from the pump to the boiler, and the water supply pump outlet water supply control valve 4 A water supply pump outlet valve 6 is connected to bypass the water supply pump outlet water supply control valve rear valve 5.

Water supply pump outlet water supply pipe 2 water supply pump outlet water supply control valve 4
A water supply pump overheat prevention valve 8 and a water supply pump overheat prevention valve rear valve 9 are inserted in the middle of the water supply pump overheat prevention pipe 7 branching from the upstream side to the deaerator. Further, a water supply pump suction flow transmitter 11 is inserted in a water supply pump suction water supply pipe 10 connected to the suction side of the water supply pump 1.

As for the water supply pump outlet water supply pipe 2 from the water supply pump 1 to the water supply pump outlet water supply control valve rear valve 5, the maximum working design pressure is from the water supply pump 1 to the water supply pump outlet water supply control valve, and the water supply pump outlet water supply. A pressure equal to the maximum working design pressure from the control valve 4 to the stop valve closest to the boiler is used.

Signals from the above-mentioned water supply pump suction flow transmitter 11, the water supply pump rotation speed transmitter 12 mounted on the water supply pump 1, and the water supply pump outlet water supply control valve opening transmitter 13 mounted on the water supply pump outlet water supply control valve 4. Is input to the water supply flow controller 14,
Further, the water supply pump outlet pressure signal 15a from the water supply pump outlet pressure transmitter 15 for detecting the discharge side pressure of the water supply pump 1 is used for outputting an alarm above a specified value and for a pressure indicator.

On the other hand, the water supply flow rate command 16 is calculated by the water supply command calculator 17 of the water supply flow rate control device 14, and the obtained water supply pump rotation speed / water supply control valve opening command 17a is supplied to the water supply pump 1 and the water supply pump outlet water supply control valve 4. Is entered.

A signal 18a from the AND circuit 18 that sets the water supply pump set rotational speed Y and the water supply pump outlet water supply control valve setting opening Z as an AND condition is guided to the water supply pump outlet valve 6, and the water supply flow rate control device 14 is also provided.
The water supply pump outlet water supply control valve rear valve opening / closing command 14a is input to the water supply pump outlet water supply control valve rear valve 5.

Next, the operation of the conventional water supply pump outlet valve control device configured as described above will be described with reference to FIGS. 3 and 4.

First, a water supply pump driving turbine (not shown) directly connected to the water supply pump 1 is reset, the water supply pump outlet water supply control valve rear valve 5 is fully opened, and the water supply pump drive turbine is gradually accelerated to a minimum operation. The rotation speed is kept constant at the rotation speed MINR. The opening operation of the water supply pump outlet water supply control valve rear valve is performed by the water supply pump outlet water supply control valve rear valve opening / closing command 14a from the water supply flow rate control device 14. In addition, the water supply pump rotation speed / water supply control valve opening command 17 output from the water supply flow rate controller 14 is used to accelerate and maintain the water supply pump 1 speed.
It is controlled by the rotation speed command in a (the water supply pump driving turbine is actually controlled, but since this and the water supply pump 1 are directly connected, they are represented by the water supply pump in the following description). During this period, the water supply pump 1 performs the minimum flow operation, and the water supply is sent to the deaerator through the water supply pump overheat prevention valve 8 and the water supply pump overheat prevention valve rear valve 9.

After time A in Fig. 4, the water supply flow rate command is issued according to the increase in load.
When 16 is increased, the feed water pump outlet feed water control valve 4 gradually increases its opening to increase the feed water as the feed water pump speed / feed water control valve opening command 17a increases, but the feed pump 1 reaches the minimum operating speed MINR. Retained.

When the water supply flow rate command 16 further increases and the required water supply cannot be obtained only by increasing the opening degree of the water supply pump outlet water supply control valve 4 in the state where the minimum operating speed MINR is maintained (time B), the rotation of the water supply pump 1 When the number of rotations is increased and exceeds the number of rotations of the water supply pump (Yrpm), the water supply pump outlet valve 6 is fully opened. Subsequent increases in the water supply flow rate in the high load region are dealt with by increasing the rotation speed of the water supply pump 1.

The series of operations described above is performed by the water supply flow rate controller 14, which outputs the water supply pump outlet water supply control valve rear valve opening / closing command 14a, water supply pump rotation speed / water supply control valve opening command 17a, rotation speed control switching / water supply pump outlet valve opening / closing. Done by signal 18a,
As the judgment factor in the control, in addition to the water supply flow rate command 16, the water supply pump suction flow rate signal 11a from the water supply pump suction flow rate transmitter 11, the water supply pump rotation speed signal 12a from the water supply pump rotation speed transmitter 12, the water supply pump In addition to the water supply pump outlet water supply control valve opening signal 13a from the outlet water supply control valve opening transmitter 13, the fully closed / fully opened signals of the water supply pump outlet water supply control valve rear valve 5 and the water supply pump outlet valve 6 are used.

In addition, at the time of switching from the water supply control by the opening degree of the water supply pump outlet water supply control valve 4 to the water supply control by the rotation speed of the water supply pump 1, the interlock for fully opening the water supply pump outlet valve 6 is a water supply pump rotation. Number signal 12a and feed pump outlet feed water control valve opening signal 13a are feed pump rotation speed signal ≧ feed pump setting rotation speed (Yrpm)… (1) feed pump outlet feed water control valve opening signal ≧ feed pump outlet feed water control valve setting Opening degree (Z%)
This is performed by the AND circuit 18 having the AND condition of (2).

The operation when the water supply flow rate is reduced or stopped is as follows.

That is, when the water supply flow rate command 16 for reducing the water supply flow rate is input, the water supply pump 1 gradually reduces the rotation speed according to the water supply pump rotation speed / water supply control valve opening command 17a, and the water supply flow rate is reduced. When it becomes lower than the fully opened flow rate of the outlet water supply control valve 4 (time D), the water supply pump outlet water supply control valve 4 starts to close. After that, the feedwater flow rate is reduced while the rotation speed of the feedwater pump 1 is reduced and the opening degree of the feedwater pump outlet feedwater control valve 4 is reduced. 13a is the feed water pump rotation speed signal ≤ feed water pump set rotation speed (Y'rpm) (3) Water feed pump outlet feed water control valve opening signal ≤ water feed pump outlet feed water control valve setting opening (Z '%) ...
When the AND condition of (4) is satisfied, the water supply pump outlet valve 6 is fully closed.

When the water supply flow rate further decreases, the opening degree of the water supply pump outlet water supply control valve 4 gradually decreases, and the water supply pump 1 also decreases its rotational speed, and is kept at the minimum operating rotational speed MINR. After that, if the water supply pump is stopped at time F, the water supply pump rotation speed signal 12a from the water supply pump rotation speed transmitter 12 causes the water supply flow rate controller 14 to supply the water supply pump rotation speed / water supply control valve opening command 17a and the water supply. Pump outlet water supply control valve rear valve open / close command 1
4a is output, and the water supply pump outlet water supply control valve 4 and the water supply pump outlet water supply control valve rear valve 5 are fully closed by the interlock.

As described above, in the water supply pump outlet valve control device in FIG. 3, the water supply flow rate control by the water supply pump outlet water supply control valve 4 (hereinafter,
It is called control valve control. ) Is performed, and the rotation speed control of the water supply pump (hereinafter referred to as rotation speed control) is performed at times B to E.
Is performed. Therefore, the control valve control and the rotation speed control are overlapped between times B to C and times D to E.

FIG. 5 shows the operation of the water supply pump outlet valve control device described above.
It is shown on the characteristic curve of the water supply pump QH during operation of one water supply pump and operation of two water supply pumps of the transformer operation plant.

In the figure, the first water supply pump is started and its rotational speed is set to the minimum operating rotational speed MINR. Minimum operating speed MI
At point a on NR, water supply pump 1 is performing a minimum flow operation, and in response to an increase command of the water supply flow rate, the water supply pump outlet water supply control valve is maintained with the rotation speed of water supply pump 1 kept at the minimum operating speed MINR. 4 is increased to increase the water supply flow rate. In this case, the operating point shifts from a to b on the minimum operating speed minr curve.

If a command to increase the water supply flow rate is further input at the operating point b, the rotation speed of the water supply pump 1 is increased along with the increase in the opening degree of the water supply pump outlet water supply control valve 4, and the water supply flow rate is increased. And the water pump rotation speed (c
Point) or more, that is, above the fully open point of the water supply pump outlet water supply control valve 4, the rotation speed control by only the water supply pump 1 is performed.

When the feed water flow rate increases after the point c, it shifts to the intersection with the feed water pump rotation speed along the system resistance curve SL, but the intersection QZ between the maximum allowable flow rate MAXF1 and the system resistance curve SL when one feed pump is operating. When performing the operation in which the increase in the water supply flow rate (that is, the load increase) is expected, the second water supply pump is additionally activated before the water supply flow rate reaches the intersection point QZ. The maximum use of the water supply pump outlet water supply pipe 2 from the water supply pump 1 to the water supply pump outlet water supply control valve rear valve 5 with a certain allowance added to the maximum value of the water supply pump outlet pressure that is expected when two water supply pumps are operating. Design pressure MAXP is determined.
The operating point in this case is the intersection point P _MAX of the system resistance curve SL and the feedwater pump speed MAXP · R at the maximum working design pressure point.

FIG. 6 is an interlock diagram for explaining the operation method of the above-described conventional water supply pump outlet valve control device. The water supply pump outlet valve 6 can be arbitrarily fully opened or closed by the push button 19, and as described above. In addition, when switching from the control valve control by the water supply pump outlet water supply control valve 4 to the rotation speed control by the water supply pump 1, the interlock for opening the water supply pump outlet valve 6 has the AND condition of equations (1) and (2). When satisfied, a full open signal is given to the water supply pump outlet valve 6 via the AND circuit 18 and the OR circuit 20. On the contrary, the interlock that closes the water supply pump outlet valve 6 when the rotation speed control by the water supply pump is switched to the control valve control by the water supply pump outlet water supply control valve 4 as the load is reduced is expressed by (3) and ( If the AND condition of equation 4) is satisfied, AND circuit 18 and OR circuit 20
A full-closed signal is given to the water supply pump outlet valve 6 via.

Further, the outlet pressure of the water supply pump 1 became abnormally high during normal operation, and the water supply pump outlet pressure high alarm point P _ANN set to a predetermined level below the maximum working design pressure of the water supply pump outlet water supply pipe 2 was exceeded. Occasionally, an alarm ANN is issued, and it is considered that the operator should take measures such as an emergency trip of the water supply pump.

(Problems to be Solved by the Invention) In the above-described conventional apparatus, in the process of additionally activating the second water supply pump to increase the water supply flow rate, the water supply control by this water supply pump is performed by the water supply pump outlet water supply control valve. When the control valve control of No. 4 is switched to the rotational speed control based on only the rotational speed of the water supply pump, the water supply pump outlet water supply control valve 4 is fully closed and the water supply pump outlet valve 6 is closed for some reason. When a situation occurs in which the water supply pump 1 does not open, that is, when the water supply pump 1 transiently enters the shutoff operation state and the water supply flow rate command to the water supply pump runs away in the increasing direction, the rotation speed of the water supply pump increases and its outlet pressure increases. Will become abnormally high, and will eventually exceed the above-mentioned maximum design pressure P _MAX .

Such a situation does not occur frequently, for example,
If an abnormality occurs in the water supply flow rate control device such as an abnormality in the water supply command calculation unit or a diode failure in the water supply flow rate control device that issues the water supply flow rate command, such as the continuous output of the water supply flow rate increase command. , The outlet pressure of the water supply pump may exceed the above-mentioned P _{MAX X} , and the water supply pump outlet water supply pipe may be destroyed.

Even with conventional equipment, such a situation is predicted and an alarm is issued at the water pump outlet high pressure alarm point P _ANN to notify the operator of the abnormality, but due to the delay in the operator's response, the water pump emergency There was a risk that measures such as stopping could not be made in time, and the rotation speed of the water supply pump would greatly exceed the alarm point P _ANN , and the water supply pump outlet water supply pipe might be damaged.

(Object of the invention) The present invention has been made to eliminate the above-mentioned drawbacks in the background art. When the control valve control by the water supply pump outlet water supply control valve is being performed, the water supply pump outlet water supply control valve is When the water supply pump is fully closed due to the cause, or when the outlet pressure of the water supply pump rises abnormally and exceeds a preset pressure, the water supply pump is tripped by opening the water supply pump outlet valve promptly. Without
Another object of the present invention is to provide a water supply pump outlet valve control device capable of preventing the shutoff operation state and protecting the water supply pump outlet water supply pipe.

[Structure of Invention]

(Means for Solving Problems) In order to achieve the above-mentioned object, the water supply pump outlet valve control device of the present invention is provided with a water supply pump that sends out the water supply sucked from the water supply pump suction water supply pipe to the water supply pump outlet water supply pipe. , A water supply pump outlet water supply control valve and a water supply pump outlet water supply control valve rear valve inserted in series in the water supply pump outlet water supply pipe, and these water supply pump outlet water supply control valve and water supply pump outlet water supply control valve rear valve are bypassed A water supply pump outlet valve control device used in a water supply system having a water supply pump outlet valve, wherein the water supply pump rotation speed and the water supply pump outlet water supply control valve opening both reach or exceed a set value. Water pump outlet valve that fully opens the outlet valve and fully closes the water supply pump outlet valve when both the water supply pump rotation speed and the water supply pump outlet water supply control valve opening become below the set values. In the control device, fully open the water supply pump outlet valve on condition that the rotation speed of the water supply pump exceeds the set value and the water supply pump outlet water supply control valve or the water supply pump outlet water supply control valve rear valve is fully closed. The AND circuit of 1 and the feed pump outlet valve are not fully opened, and the signal from the first AND circuit is present, the feed pump raising lock is activated, and the rotational speed of the feed pump is currently set. Second AN to keep
And a D circuit.

(Operation) In the water supply pump outlet valve control device of the present invention configured as described above, the water supply pump outlet water supply control valve or the water supply pump outlet water supply control valve rear valve is fully closed, and the rotation speed of the water supply pump is When the value is equal to or more than the predetermined value, the first AND circuit is A
When the ND condition is satisfied and a full open signal is sent to the water supply pump outlet valve, and if the water supply pump outlet valve does not fully open regardless of this command, the detection signal and the signal of the first AND circuit are combined with the second AND circuit. Since the rotation speed of the water supply pump is locked and maintained as it is by its output, an abnormal pressure rise at the water supply pump outlet water supply pipe is reliably prevented.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the water supply pump outlet valve control device of the present invention. The water supply pump outlet valve 6 can be fully opened or closed arbitrarily by a push button 19, and as described above, the water supply pump outlet water supply adjustment. When the interlock for opening the feed water pump outlet valve 6 satisfies the AND condition of the equations (1) and (2) when switching from the control valve control by the valve 4 to the rotation speed control by the water feed pump 1, the AND circuit 18 OR circuit 20
A full open signal is given to the water supply pump outlet valve 6 via.
On the contrary, the interlock that closes the water supply pump outlet valve 6 when the rotation speed control by the water supply pump is switched to the control valve control by the water supply pump outlet water supply control valve 4 as the load is reduced is expressed by (3) and ( When the AND condition of formula 4) is satisfied, the feed water pump outlet valve 6 is connected via the AND circuit 18 and the OR circuit 20.
Is given a fully closed signal.

Further, the outlet pressure of the water supply pump 1 became abnormally high during normal operation, and the water supply pump outlet pressure high alarm point P _ANN set to a predetermined level below the maximum working design pressure of the water supply pump outlet water supply pipe 2 was exceeded. Occasionally, an alarm ANN is generated to allow operators to take actions such as water pump emergency trips.

The above construction is similar to that of the conventional apparatus described with reference to FIG. 6, but in the present invention, a two-stage protection circuit is further provided for the shutoff operation of the water supply pump.

The first protection circuit is the water supply pump outlet water supply control valve fully closed e
Alternatively, an OR circuit 21 that produces an output when either one or both of the conditions of the water supply pump outlet water supply control valve rear valve fully closed f are satisfied, and this OR circuit output and a predetermined set speed S _rpm or more g of the water supply pump The first AND that produces the outputs h, i under the AND condition
It consists of a circuit 22.

The output h is guided as an alarm signal ANN1 to an alarm device (not shown) to notify the operator of the occurrence of an abnormality. Output i is OR circuit 20
Is introduced to the water supply pump outlet valve 6 and unconditionally fully opens the water supply pump outlet valve. Further, when the AND condition of the AND circuit 22 is not satisfied, the NOT circuit 23 outputs the signal i, and this signal is added to the water supply pump outlet valve 6 via the OR circuit 20,
The water supply pump outlet valve 6 is fully closed.

Since the water supply pump outlet valve 6 is not fully opened in spite of the input of the output i described above, the NOT circuit 24 produces a signal j indicating that the water supply pump outlet valve 6 is not fully opened. The signal k from the AND circuit 22 is input to the second AND circuit 25, and the signal l output by the establishment of those AND conditions is input to the feedwater pump rotation speed increasing lock 26 to keep the rotation speed of the feedwater pump as it is. At the same time, the signal m is guided as an alarm signal ANN2 to an alarm device (not shown) to notify the operator of the abnormality.

The above is the first stage protection circuit in the device of the present invention,
This makes it possible to suppress an abnormal rise in the supply water pressure at the outlet of the water supply pump, but in this embodiment, a second-stage backup protection circuit is additionally provided in order to ensure a more reliable operation.

This backup protection circuit provides a signal n when the feed water pressure at the outlet of the water supply pump becomes equal to or higher than the high pressure setting value (P _max −α) kg / cm ^{2 of} the water supply pump outlet pressure that is set to a predetermined value that is lower than the maximum design pressure. , n ′ are output, and the signal n is the OR circuit 20.
It is input to the water supply pump outlet valve 6 via and is unconditionally fully opened.

Further, when the water supply pump outlet valve 6 is fully opened by the signal n, but the water supply pump outlet valve is not opened, the signal n ′ is passed through the OR circuit 27 and the second signal together with the signal j.
Is input to the AND circuit 25, and the rotation speed of the water supply pump is maintained at the current state by the water supply pump rotation speed increasing lock 26 as in the case described above, and at the same time, the alarm signal ANN2 is output.

In addition, the above-mentioned high setting value of the water supply pump outlet pressure (P _max −α)
kg / cm ² is the outlet pressure of the water supply pump in the range where it is not normally operated, and is set to a value with a certain allowance with respect to the maximum operating design pressure.

FIG. 2 shows the main set points in the device of the present invention on the QH characteristic curve of the water supply pump of the transformer power plant set in FIG. 5, and the water supply is performed only by the opening of the water supply pump outlet water supply control valve. An arbitrary number of revolutions S _rpm of the water feed pump is set in the water feed control region that exceeds the control regions a and b. The condition of the set speed S or higher and the condition that the water supply pump outlet water supply control valve is fully closed or the water supply pump outlet water supply control valve rear valve is fully closed.
When the OR condition is satisfied, the AND circuit 22 satisfies the AND condition,
Fully open the water supply pump outlet valve.

As the backup protection circuit for this first stage protection circuit, the maximum operating design pressure operating point P _MAX on the system resistance curve SL
, And the maximum value of the maximum design pressure MAXP with an allowance set at the feed pump outlet pressure high set value (P _max −α) kg / cm ²
When the above is reached, the water supply pump outlet valve is fully closed.

As described above, the two protection circuits that fully close the water supply pump outlet valve control the water supply pump so that the water supply pump will not be shut off under any operating condition. When the water supply pump outlet valve is not fully opened, the water supply pump speed increasing command is automatically locked.

Due to these effects, the operating point of the feed pump is set at the outlet high pressure of the feed pump (P _max −α) kg / cm ² and the system resistance curve.
It does not cross the intersection W with SL.

An abnormal alarm for the operator is automatically issued as ANN1 and ANN2 when the conditions of AND circuits 22 and 25 are satisfied.Therefore, set the alarm level P _ANN to the water supply pump outlet water supply pressure, and when it exceeds this, the alarm ANN It is not always necessary to issue.

〔The invention's effect〕

As described above, in the water supply pump outlet valve control device of the present invention, the water supply pressure of the water supply pump outlet water supply pipe is surely prevented from exceeding the maximum design pressure, and the water supply pump and the water supply pump do not trip the water supply pump. The outlet water pipe can be operated safely.

[Brief description of drawings]

FIG. 1 is an interlock diagram functionally showing the configuration of the device of the present invention, FIG. 2 is a graph showing the operation of the device of the present invention on a water feed pump QH characteristic curve, and FIG. FIG. 4 is a block diagram showing the configuration, FIG. 4 is a time chart for explaining the operation of the apparatus of FIG. 3, FIG. 5 is a graph showing the operation of the conventional apparatus on a water feed pump QH characteristic curve, and FIG. It is an interlock figure of an apparatus. 1 ... Water supply pump, 2 ... Water supply pump outlet water supply pipe, 3 ...
Check valve, 4 ... Water supply pump outlet water supply control valve, 5 ... Water supply pump outlet water supply control valve Rear valve, 6 ... Water supply pump outlet valve, 7 ... Water supply pump overheat prevention pipe, 8 ... Water supply pump overheat Prevention valve, 9 …… Water supply pump overheat prevention valve rear valve, 10 …… Water supply pump suction water supply pipe, 11 …… Water supply pump suction flow transmitter, 12 …… Water supply pump rotation speed transmitter, 13 …… Water supply pump outlet water supply Control valve opening transmitter, 14 ... Water supply flow rate control device,
15 …… Water pump outlet pressure transmitter, 16 …… Water supply flow rate command, 17 …… Water supply command calculator, 18 …… AND circuit, 19 …… Push button.

Claims (3)

[Claims] Claims: 1. A water supply pump for feeding water supplied from a water supply pump suction water supply pipe to a water supply pump outlet water supply pipe, and a water supply pump outlet water supply control valve and a water supply pump outlet which are inserted in series in the water supply pump outlet water supply pipe. A water supply pump outlet valve control device used in a water supply system comprising a water supply control valve rear valve and a water supply pump outlet water supply control valve and a water supply pump outlet water supply pump outlet valve that bypasses the rear valve. , The feed water pump outlet valve is fully opened when both the feed water pump rotation speed and the feed water pump outlet feed water control valve opening become equal to or more than the set values, and the feed water pump rotation speed and the feed water pump outlet feed water control valve opening are both set values. In the water supply pump outlet valve control device that fully closes the water supply pump outlet valve when the following occurs, the rotation speed of the water supply pump exceeds the set value, and the water supply pump outlet water supply control valve Or a first AND circuit that fully opens the water supply pump outlet valve on condition that the rear valve of the water supply pump outlet water supply control valve is fully closed, and the first water supply pump outlet valve is not fully opened, and the first AND circuit Water supply pump for activating the rotation speed increasing lock of the water supply pump on the condition that a signal from the AND circuit is present and maintaining the rotation speed of the water supply pump at the current state. Outlet valve control device. 2. A water supply pump outlet pressure high set value (Pmax-α) kg / c in which the outlet water supply pressure of the water supply pump is set with a certain margin from the maximum working design pressure of the water supply pump outlet water supply pipe.
The signal generated when m ² is exceeded is input to the OR circuit together with the signal from the first AND circuit, and the output of this OR circuit is input to the second
The feed water pump outlet valve control device according to claim 1, characterized in that the feed water pump outlet valve control device is configured to input to one terminal of an AND circuit. 3. The feed water pump outlet valve control device according to claim 1, wherein the output of the first or second AND circuit is used as an alarm signal.