JPH109145A - Automatic water-supply method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically control the water-supply pressure of a pump even if the water-supply pressure drops below the stopping pressure of the pump through the setting of the starting pressure and the stopping pressure of the pump only one time, by successively updating the stopping-pressure value of the pump to a pressure value just after the stoppage of the pump every time the rate of change in water-supply pressure gets smaller than a reference value. SOLUTION: A water-supply pressure P' just after the forcible stoppage of a pump is stored in a memory, and a water-supply pressure P" after the lapse of a predetermined unit time ΔT is detected. The difference ΔP between the water-supply pressure P" and the water-supply pressure P' just after the stoppage of the pump are calculated, and the rate of change ΔP/ΔT in the unit time ΔT is obtained. The value of the rate of the change is then compared with a predetermined reference value (a) for the determination of its relative largeness or smallness. If the rate of change ΔP/ΔT is smaller than the reference value (a), the value of a stopping pressure P2 of the pump is updated to the water-supply pressure P' just after the forcible stoppage. The above process from the initial setting is repeated to successively update the stopping pressure every time the rate of change gets smaller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic water supply system in which a pump is operated by a control means, and more particularly to a water supply pressure which can be kept uniform even when the amount of water used becomes extremely small. About things.

[0002]

2. Description of the Related Art In recent years, an automatic water supply device having a small pressure tank has become widespread for supplying water to apartment houses such as apartments and condominiums. The automatic water supply device is disclosed, for example, in Japanese Patent Application Laid-Open No. 48-24303. As shown in (first prior art), the pressure switch is turned on / off in response to the pressure in the pressure tank to start / stop the pump.
There is something to stop.

[0003] Alternatively, as disclosed in Japanese Patent Publication No. 57-35483 (hereinafter referred to as a second prior art), a control valve is provided, and the control valve supplies water to the piping system in response to a change in pressure in the piping system. Some are designed to prevent water from flowing or to prevent water from flowing.

[0004]

However, the first and second prior arts described above have a problem in that the water supply pressure is not fixed.

That is, in the first prior art, the pump is operated / stopped by turning on / off the pressure switch. The water supply pressure is extremely large, and the water supply pressure cannot be kept constant during that time. For this reason, when the water supply pressure is high when the user opens the faucet, there is a problem that if the water supply pressure is high, the water gets into the atmosphere and becomes cloudy or scatters. In addition, there is a problem that the instantaneous water temperature of the water heater fluctuates.

In the second prior art, the control valve supplies or stops water to the piping system in accordance with fluctuations in the pressure of the piping system. However, the amount of water used is extremely low. However, when the water volume becomes extremely small, the water supply pressure rises remarkably and does not become a constant pressure. Therefore, the same problem as in the first prior art is caused, and the structure of the control valve itself is complicated. Etc. are easily clogged and it is difficult to maintain the function of the control valve.
A problem arises that frequent maintenance is required.

In view of the above circumstances, it is an object of the present invention to set the start pressure and the stop pressure of the pump once, and to automatically adjust the supply pressure even if the feed water pressure becomes lower than the stop pressure due to wear of the pump. Another object of the present invention is to provide an automatic water supply method capable of performing the above-mentioned method.

[0008]

According to the present invention, there is provided an automatic water supply apparatus for starting and stopping a pump in accordance with a water supply pressure discharged from a pump. When the starting pressure is reached, the pump is operated in one of the preset operation time and the time until the stop pressure is reached within the range of the operation time only when the feed water pressure does not reach the stop pressure. B) Whenever the rate of change between the water supply pressure when the pump stops and the water supply pressure after a specific time has passed becomes smaller than the reference value, the pump stop pressure value is stopped. The feature is that the pressure value is updated successively to the pressure value immediately after the pressure has been set.

Further, the apparatus according to the present invention has a control means for starting and stopping the pump in accordance with the feed water pressure and the stop pressure discharged from the pump, and the control means determines in advance the starting pressure of the pump and the stop pressure. An input section for inputting the stop pressure, and at the time when the feed water pressure reaches the starting pressure of the pump as detected by the pressure sensor, the pump is operated at a preset operation time and a predetermined operating time only when the feed water pressure does not reach the stop pressure. An operation section that is operated and stopped at any one of the time until the stop pressure is reached within the range of the operation time, and a water supply pressure immediately after the pump is stopped and a water supply pressure after a specific time has elapsed from the detection thereof. A pump stop pressure adjusting device comprising: an update unit that obtains the rate of change and updates the value of the pump stop pressure to the pressure immediately after the pump stops, each time the obtained rate of change becomes smaller than the reference value. Is characterized in that the obtaining.

In the method of the present invention, a) When the feed water pressure reaches the starting pressure of the pump, the pump is operated within the preset operating time and within the range of the operating time only when the feed water pressure does not reach the stop pressure. (B) the rate of change between the water supply pressure when the pump stops and the water supply pressure when a specific time has elapsed after the pump stops, and Since the value of the pump stop pressure is sequentially updated to the pressure value immediately after the pump stops every time it becomes smaller, the pump wear pressure can be reduced as long as the pump stop pressure is input as an initial value in advance. Even if the discharge pressure may drop below the initial stop pressure due to this, it is possible to prevent the pump from not stopping due to the successive update of the stop pressure, and it is not necessary to adjust the stop pressure. .

Further, in the device of the present invention, as described above, the control means includes the pump stop pressure adjusting device including the input unit, the operating unit, the comparing unit, and the updating unit, so that the above method can be accurately performed.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 show a first embodiment of the automatic water supply apparatus according to the present invention.

In the automatic water supply apparatus of the embodiment, as shown in FIG. 1, a water receiving tank 1 is connected to a suction part of a pump 3 via a suction pipe 2, and a discharge part of the pump 3 is connected to a water supply pipe 4. I have. A gate valve 5 is provided at an intermediate position of the suction pipe 2. The water supply pipe 4 is provided with a check valve 6 and a gate valve 7 at a position close to the pump 3, and a pressure tank 8 that stores discharge water from the pump and raises the pressure to a desired pressure downstream of the gate valve 7. Is provided.

Further, a pressure tank 8 is connected to the water supply pipe 4.
A pressure sensor 9 for detecting the pressure of the water supply is provided downstream of. The pressure sensor 9 always detects the feedwater pressure and outputs the detected value to the control means 10 as a current.

The control means 10 adjusts the feed water pressure based on the output from the pressure sensor 9 to the pressure at which the pump 3 is to be started (hereinafter referred to as the pressure).
When the water supply pressure reaches a pressure at which the water supply pump 3 should be stopped (hereinafter referred to as a pump stop pressure), the pump 3 is stopped. Therefore, the pump 3 is controlled.

In this embodiment, the control means 10 determines that the difference between the pump start pressure and the pump stop pressure is 1 to 1.5 kgf.
/ Cm ² .

Further details will be described with reference to FIG. FIG. 2 is an operation characteristic diagram of the pump in which the pressure is plotted on the vertical axis and the amount of water is plotted on the horizontal axis. In the figure, A is a QH performance curve of the pump 3, and B and C are resistance curves of valves, piping, and the like that can be considered in design. Further, Qmax is the maximum amount of water used by the water supply system, and HT is the total head. HT is the sum of the pipe resistance Hf and the head HI consisting of the actual head Ha and the pressure Hp at the end of the water supply system in the water supply.

The resistance curve B has a QH performance curve A and an intersection L of a line obtained by extending the total head HT horizontally, and a water amount of 0.
The resistance curve C is set as a curve connecting the point H and the point G on the QH performance curve A, with the curve connecting the point (zero) and the intersection G of the head HI. I have. Q
A point H on the -H performance curve A is an intersection of the QH performance curve A and the pipeline resistance curve C, and the stop time is sufficient and the pump is started with respect to the pump stop command point P 'predicted in advance. It is set so that the water supply pressure does not drop by then.

Here, the control means 10 determines that the difference between the starting pressure P1 for starting the pump 3 and the stop pressure P2 for stopping the pump 3 is approximately 1 to 1.5 kgf /
We are determined to cm ^2.

The starting pressure P1 includes an upper limit pressure that can be selected by the pump 3 in the total head HT, a pipe resistance curve C obtained based on the upper limit pressure value, and a water amount at which the amount of water used should be the minimum point F (normally). Then, 10-2 l / min, which is equivalent to 1-2 faucets
Is set to a value determined at the intersection of the pipeline resistance curve C and the line extending upward from the minimum demand water amount point F in this example. It may be set to be higher than the position and lower than the H point. When the feed water pressure reaches the pressure value, the pressure sensor 9 detects the start pressure P1, and the control means 10 starts the pump 3.

The stop pressure P2 is set slightly lower than the stop command point P2 'and higher than the point H. Stop command point P
2 'is set at the intersection of the QH performance curve A and the line at which the demand water minimum point F extends further above the pump starting pressure P1. In this case, the start pressure P1 and the stop pressure P2
Is approximately 1 to 1.5 kgf / cm ² , so that the pressure difference between the position of the stop command point P 2 ′ and the position of the point L is approximately 1 to 1.5 kgf / cm ^2. QH performance curve, and the above point H
O, which is a point obtained by extending the point H horizontally, a point L,
A pump 3 having a desired maximum water amount Qmax and a total head HT is used in a range between the point L and a point D extending horizontally.

As described above, the pump 3 having the QH performance curve of the flat type is used, and the starting pressure P1 of the pump 3 is used.
The pressure difference between the stop pressure P2 and the control
To about 1 to 1.5 kgf / cm ² , so that the starting pressure P1 and the stopping pressure P2 of the pump 3 are determined in advance.
When the feedwater pressure reaches the starting pressure P1, the pressure sensor 9 detects the feedwater pressure, and the control means 10 starts the pump 3. When the pump 3 is operated, the feedwater pressure becomes P2 '. If it reaches, the pressure sensor 9 detects it and issues a stop command of the pump 3, and the pump 3 is completely stopped at the stop pressure P2. Even if the amount becomes small, it is possible to reliably prevent the water supply pressure from fluctuating.

As a result, the water supply pressure can be prevented from significantly fluctuating while the pump is stopped from operating, as compared with the conventional example using the pressure switch, and compared with the conventional example using the control valve. Since the pressure fluctuation can be prevented even when the usage amount reaches the minimum point F, the water supply pressure can be almost surely made uniform.

FIG. 3 and FIG. 4 show an embodiment of a pump stop pressure adjusting device for carrying out the pump stop pressure adjusting method in the automatic water supply device according to the present invention. In this case, if the water supply pressure falls below a predetermined stop pressure P2 due to wear of the pump 3, the pump 3 may not stop. Therefore, in this embodiment, the stop pressure P2 is automatically updated by a microcomputer (hereinafter, simply referred to as a microcomputer) used as the control means 10.

More specifically, in FIG.
S and T are power supplies, MB is a circuit breaker, R and S are control power supplies, MCa is a contact of the electromagnetic switch MC, and TH is a motor I.
Mb thermal relay sensor for overload protection, THb
Is the contact point. S is a power switch, and Z is a DC smoothing stabilized power supply, which supplies power to the microcomputer via a power supply terminal A as control means.

The microcomputer serving as the control means 10 mainly includes an input port P for receiving outputs from the processing section MPU, the memory M, and the pressure sensor 9 via the interface I / O-1.
io-B, an input port Pio-C for taking in outputs from the switches SW1 and SW2, and an output port Pio-A for outputting based on the processing result in the processing unit MPU.

Further, this microcomputer also has a pump stop pressure adjusting device. The pump stop pressure adjusting device is an MPU
The operation time t1 set in advance only when the feed water pressure does not reach the stop pressure P2, or the operation time t1
Even within the range, the pump 3 is operated and stopped at any one of the time until reaching the stop pressure P2. At this time, the change rate ΔP / ΔT between the feed water pressure immediately after the pump 3 is stopped and the feed water pressure detected when the specific time ΔT has elapsed after that is obtained, and the change rate ΔP / ΔT
The magnitude of ΔT is compared with a predetermined reference value a. As a result, only when the rate of change ΔP / ΔT becomes smaller than the reference value a, the feedwater pressure immediately after the stop is set as the subsequent pump stop pressure P2. I try to update.

The reference value a is a measure for judging the rate of change between the feed water pressure immediately after the pump 3 is stopped and the feed water pressure after the lapse of the specific time ΔT. (The amount of water held in the pressure tank when the supply water pressure changes from the start pressure P1 to the stop pressure P2) and the amount of water used when the pump is stopped, for example, 0.2 kgf
/ Cm ² / sec, but this value can be arbitrarily changed by a reference value adjustment switch (not shown) or the like.

Further, SW1 and SW2 are for selecting and inputting the values of the starting pressure P1 and the stopping pressure P2 of the pump 3 in advance, respectively, and comprise, for example, dip switches.

In this embodiment, first, the operation preparation of the automatic water supply device is completed, and the circuit breaker MB for wiring is turned on.
When the power switch S is closed, the microcomputer performs an initial setting as shown in FIG. 4 (401). That is, the starting pressure P1 of the pump 3 is set by the switch SW1, and the switch S1
When the stop pressure P2 of the pump 3 is selected from W2, the start pressure P1 and the stop pressure P2 are stored in the memory M.

When the pressure sensor 9 measures the feed water pressure P when the pump 3 is stopped, the microcomputer takes in the measured feed water pressure P from the input port Pio-B via the interface I / O-2, and the memory M (402). Next, it is determined whether or not the water supply pressure P is lower than the previously stored starting pressure P1 of the pump 3 (403).

As a result, if the feedwater pressure P is higher than the starting pressure P1, the processing after step 402 is repeatedly executed until the feedwater pressure P becomes lower. However, if the feedwater pressure P is lower than the starting pressure P1, the microcomputer sends the output port Pio-A to the output port Pio-A. The pump 3 is started by outputting the signal via the interface I / O-1 and exciting the electromagnetic switch MC (404).

In this case, it is determined whether or not the operation time of the pump 3 has reached a predetermined time t1, and as a result,
When the time t1 is reached, the pump 3 is forcibly stopped.
On the other hand, when the time is less than the time t1, the current water supply pressure is measured by the pressure sensor 9 during the time t1 (40).
7) The measured feed water pressure is the stop pressure P2 of the pump 3.
It is determined whether or not it is greater than (408).
6 is executed, but if it is smaller, the processing after 405 is repeatedly executed.

Therefore, when the feed water pressure P is smaller than the starting pressure, the operation is performed only during the time t1, and the operation is performed during the time t1.
The operation is performed as long as the supply water pressure does not exceed the stop pressure P2.

When the pump 3 is forcibly stopped, the feed water pressure P 'immediately after the stop is detected by the pressure sensor 9 and stored in the memory M (409). Then, a predetermined unit time ΔT (for example, 1 second) is measured by a timer (not shown) of the microcomputer, and when the time ΔT elapses (41)
0), a pressure sensor 9 for detecting a change in the feed water pressure P ″ immediately after the stop of the pump 3 and a change in the feed water pressure P ′ after the lapse of the time ΔT, further detects the present feed water pressure P ″, and detects the feed water pressure P ″. The difference ΔP (P′−P ″) between P ″ and the feed water pressure P ′ immediately after the stop of the pump 3 is calculated, and the unit time ΔT
Then, the ratio of the change rate ΔP / ΔT in is obtained (411).

When the rate of change ΔP / ΔT is obtained, the magnitude of the value is compared with a predetermined reference value a to determine (412).
As a result, when the change rate ΔP / ΔT is larger than the reference value a,
The processing after step 402 is repeatedly executed, but if the value is smaller than the reference value a, the value of the stop pressure P ′ detected at 409 is
Is updated as the value of the stop pressure P2 of (413), and 40
By repeating the processing from step 1, the rate of change ΔP / ΔT
The value of the stop pressure is automatically and successively updated each time is smaller.

Therefore, the reference value a is set to the water taps 1-2 of the used water amount.
When the stop pressure P2 is determined so as to correspond to about the minimum point F, the stop pressure P2 is sequentially updated, and finally, the stop pressure P2 can be converged to the stop command point P2 'considered to be appropriate. The value of the pressure P2 can be set near the minimum point F. As long as the start pressure P1 and the stop pressure P2 of the pump 3 are input as initial values in advance by the switches SW1 and SW2, the discharge pressure becomes initial due to the wear of the pump 3. Even if the value becomes lower than the stop pressure P2, it can be prevented that the pump 3 does not stop, and there is no need to adjust the stop pressure P2 again.

In the illustrated embodiment, an example is shown in which a microcomputer is used as the control means. However, the present invention is not limited to this. Although not shown, for example,
The control means obtains a change rate ΔP / ΔT, compares an input section for inputting the start pressure P1 and the stop pressure P2, an operation section for operating and stopping the pump 3 with the reference value a, and compares the change rate ΔP
A similar function and effect can be obtained by configuring the pump stop pressure adjusting device with an updating unit that updates the stop pressure successively each time / ΔT becomes smaller than the reference value a. In addition to a switch that can arbitrarily adjust the values of the starting pressure P1 and the stop pressure P2, if a switch that can also arbitrarily adjust the value of the reference value a is provided, the water supply pressure can be adjusted according to the scale and use of the automatic water supply device. Can be delicately and easily controlled.

FIGS. 5 and 6 show a second embodiment of the automatic water supply apparatus of the present invention. In this case, a microcomputer is used as the control means 10, and a pressure switch 11 and a flow rate sensor 12 are used instead of the pressure sensor 9.

That is, in FIG. 5, the pressure switch 11 is for detecting the starting pressure P1 of the pump 3, and the flow switch 12 is for detecting the minimum water amount F of the used amount. It is connected to the input port Pio-B of the microcomputer via O-2. In FIG. 5, the same reference numerals as those in FIG. 3 denote the same components, and a description thereof will be omitted.

In this embodiment, as shown in FIG. 6, during operation of the automatic water supply device, when the water supply pressure drops to the pump starting pressure P1, the pressure switch 11 detects this and turns on (601). Causes the microcomputer to start the pump 3 (602). In this case, when the amount of water used reaches the minimum water amount point F, the flow rate sensor 12 detects this, the pump 3 is stopped by the microcomputer, and the processing after 601 is repeated to keep the water supply pressure almost uniform. 1 and 2 basically.
The same effect as that of the embodiment shown in FIG. In addition,
In this case, the pressure switch 11 closes the contact at the starting pressure P1 and opens the contact when the pressure is higher than the pressure P1. When setting P1, as described in the embodiment of FIGS. 1 and 2, There is no problem if it is in the range between the position of P1 and the point H, but in this case, when the effective volume of the pressure tank 8 is maximized, the stopping time of the pump 3 becomes longer, and the starting frequency of the pump 3 becomes lower. In consideration of the above, it is desirable to set the value on or near the pipeline resistance curve C.

As described above, according to the first aspect of the present invention, the stop pressure of the pump can be updated as needed, so that the stop pressure of the pump can be input as an initial value in advance. For example, even if the discharge pressure may be lower than the initial stop pressure due to the wear of the pump,
It is possible to prevent the pump from not stopping due to the successive updating of the stop pressure, and it is not necessary to adjust the stop pressure. As a result, the operability is good and the handling is easy. For example, since the value of the reference value can be adjusted, the water supply pressure can be delicately and easily controlled according to the scale and use of the automatic water supply device.

According to the third aspect, the control means of the automatic water supply apparatus includes the pump stop pressure adjusting device including the input unit, the operating unit, and the updating unit, so that the method of the first aspect can be accurately performed. According to the fourth and fifth aspects, there is an effect that it is possible to delicately and easily control a constant water supply pressure according to the scale and use of the automatic water supply apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic piping diagram for explanation showing a first embodiment of an automatic water supply device according to the present invention.

FIG. 2 is an operation characteristic diagram of a pump in which pressure is shown on a vertical axis and a water amount is shown on a horizontal axis.

FIG. 3 is an overall circuit diagram for explaining an automatic water supply device showing one embodiment of a pump stop pressure adjusting device in the automatic water supply device according to the present invention.

FIG. 4 is a flowchart showing control contents of a pump stop pressure adjusting device.

FIG. 5 is an overall circuit diagram for explanation showing another embodiment of the automatic water supply device according to the present invention.

FIG. 6 is a flowchart showing the control contents of the automatic water supply device.

[Explanation of symbols]

3 ... pump, 9 ... pressure sensor, 10 ... control means, 11 ...
Pressure switch, 12: flow rate sensor, A: QH of pump
Performance curve, P1: pump start pressure, P2: pump stop pressure, SW1, SW2: switch of input unit, t1: operation time, P ': pressure immediately after pump stop, ΔT: specific time, P ″: specific time Pressure after passage, ΔP / ΔT: change rate, a: reference value.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Endo 7-1-1, Higashi-Narashino, Narashino-shi, Chiba In the Narashino Plant of Hitachi, Ltd. Techno Engineering Co., Ltd.

Claims (5)

[Claims] 1. An automatic water supply device for starting and stopping a pump in accordance with a water supply pressure discharged from the pump, the method comprising: a) when the water supply pressure reaches a pump start pressure, the pump is turned on; Only when the pump pressure does not reach the predetermined operating time or the time until the stop pressure is reached within the range of the operating time. Automatic water supply characterized by successively updating the value of the pump stop pressure to the pressure value immediately after the pump is stopped every time the rate of change from the feedwater pressure when a specific time has elapsed thereafter becomes smaller than the reference value. Method. 2. The automatic water supply method according to claim 1, wherein the reference value is adjusted to an arbitrary value. 3. A control means for starting and stopping the pump in accordance with the feed water pressure and the stop pressure discharged from the pump, wherein the control means detects the feed water pressure by detecting the pressure sensor and changes the feed water pressure to the starting pressure of the pump. When the pump reaches the stop pressure, the pump is operated for one of the preset operation time and the time until the stop pressure is reached within the range of the operation time only when the feed water pressure reaches the stop pressure. A driving unit that stops by
Each time the rate of change of the feedwater pressure immediately after the pump stops and the change of the feedwater pressure after the specific time detected after the specified time has become smaller than the reference value, the value of the pump stop pressure is changed to the pressure value immediately after the pump stops. An automatic water supply device comprising a pump stop pressure adjusting device comprising an updating unit for sequentially updating the pump stop pressure. 4. The automatic water supply device according to claim 3, wherein the input unit includes a reference value adjustment switch that can adjust a reference value to an arbitrary value. 5. The automatic water supply apparatus according to claim 3, wherein the input unit includes an adjustment switch capable of arbitrarily changing values of a starting pressure and a stopping pressure of the pump.