JP2001153056A - Water supply equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water supply equipment capable of accurately integrating water consumption by reducing the excessively proceeding phenomenon of a water meter. SOLUTION: This water supply equipment is provided with a water meter 21 on the inflow side, and supplies water to end-users by pressurizing the water measured by the above water meter by using a pump 11, and the water supply equipment is also provided with a small quantity water stopping function to stop operation of the pump 11 when water consumption is reduced to a very small water quantity, and the above small quantity water stopping function has a predetermined condition to suppress the excessively proceeding phenomenon of the water gauge 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a water supply device,
In particular, the present invention relates to a water supply device that supplies water such as tap water to an apartment house, a building, and the like using a pump.

[0002]

2. Description of the Related Art FIG. 1 shows an example of the construction of a water supply system of a type directly connected to a general water main. This water supply apparatus includes a pump 11 and pressurizes water flowing through an inflow pipe 12 directly connected to a water main pipe or the like by the pump 11 to supply a water to a discharge pipe 13.
From the end to the hydrant of the end customer. A check valve 15 is provided on the discharge side of the pump 11 to prevent backflow of water when the pump stops. Further, a pressure tank 16 is provided to accumulate water pressurized by the pump 11 so as to avoid frequent starting and stopping of the pump. Further, a pressure sensor 17 for detecting the pressure on the pump discharge side is provided near the pressure tank of the discharge pipe 13, and the detected pressure signal is transmitted to the control panel 19 and used for operation control of the pump.

Similarly, the inflow pipe 12 is provided with a pressure sensor 18 on the pump inflow side, and this signal is transmitted to a control panel 19 and used for controlling the operation of the pump. In the control panel 19,
By providing an inverter device and supplying a variable frequency and voltage to the pump 11, the rotation speed of the pump 11 is arbitrarily controlled. Therefore, the pressure on the pump discharge side is detected by the pressure sensor 17, and the pump discharge side pressure is controlled to the target pressure value by changing the rotation speed of the pump so that the pump discharge side pressure becomes constant. it can. Control panel 19
Performs selection of a pump to be operated, start and stop, detection of various abnormal signals such as abnormal temperature of the pump, and generation of an alarm.

[0004] The water supply apparatus is provided with a flow switch 20 for detecting a minimum amount of water.
Is transmitted to When the flow switch 20 detects the extremely small amount of water, the control panel 19 receives the signal and operates the pump for a certain period of time to accumulate pressure in the pressure tank 16 and thereafter has a so-called small water amount stop function of stopping the operation of the pump. ing. This function can prevent frequent starting and stopping of the pump when the amount of used water is extremely reduced at night or the like, and can prevent the pump from running idle. As such a small amount of water stop operation, the pump is stopped at the same pressure at the time of detection of the extremely small amount of water, and after the stop, when the discharge side pressure drops by a predetermined value from the target pressure, the pump is restarted, or After the discharge pressure of the pump is once increased to accumulate the pressure in the pressure tank, the pump is stopped, and the pump is restarted when the pressure on the discharge side drops below the target pressure by a predetermined value.

When supplying tap water or the like, a water meter is generally installed to measure the amount of water used. When such a water supply device is used as a direct connection type water supply device directly connected to a water main, a water meter 21 is attached to an inflow pipe of the water supply device, and a water meter 22 is also attached to each customer. May be used. The water meter 21 attached to the inflow side of the water supply device has a water meter attached to, for example, a 40 mmφ pipe in order to measure the entire amount of water supplied. On the other hand, a discharge pipe 1
The water supplied from 3 is supplied in a distributed manner, and a water meter 22 is attached to each of these doors, for example, in a pipe of 20 to 25 mmφ. In this way, the total amount of water used is measured at the inflow side of the water supply device, and the total water usage of each water meter 22 of each pipe branched to the discharge side of the water supply device is compared.
It has been known that when used continuously for a long time with an extremely small amount of water, a difference may occur in the integrated water amount between the two. This phenomenon occurs when the integrated water amount on the inflow side becomes larger than the total integrated water amount on the discharge side, and occurs in connection with the above-described small water amount stop operation, and is called a water meter overrun phenomenon. For example, with a relatively small-scale water supply device, the water meter 21 provided on the inflow side and the water meter 22 provided on the customer side can be used without installing the water meter in some customers. There may be problems when subtracting the total to calculate the water usage of consumers without water gauges.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and provides a water supply device capable of reducing the overrun phenomenon of the water meter and accurately integrating the used water amount. The purpose is to:

[0007]

According to the first aspect of the present invention, a water meter is provided on the inflow side, and the water measured by the water meter is pressurized using a pump and sent to the end customer. A water supply device, the water supply device having a small water amount stop function for stopping the operation of the pump when the amount of water used becomes an extremely small amount of water, and the small water amount stop function is an excessive phenomenon of a water meter provided on the inflow side. It is a water supply device provided with the setting conditions which suppress.

It is considered that the excessive movement of the water meter occurs due to a sudden change in the flow rate on the inflow side during the operation of stopping the small amount of water. For this reason, by setting various conditions of the water supply device so that the change of the inflow-side flow rate is performed gently at the time of the small water amount stop operation, it is possible to alleviate the excessive movement phenomenon of the water dispenser and reduce it. . According to such a water supply device, even when a water meter is provided on the inflow side, the amount of occurrence of the excessive traveling phenomenon is small, so that the water supply device can be used with confidence.

It is preferable that the set conditions are to reduce the frequency of occurrence of the low water amount stop operation. This allows
If the operation of stopping the small amount of water is performed in a state where the amount of water used is extremely reduced, more or less water is accumulated in the tank,
A pulsed change in the inflow rate occurs. It is considered that the excessive phenomenon of the water meter is caused by the change of the pulse-like inflow amount, and by reducing the frequency of occurrence, the excessive phenomenon can be reduced.

It is preferable that the set condition is based on reducing the capacity of a pressure tank for accumulating pressure when a small amount of water is stopped. Thus, the amount of change in the pulse-like inflow amount that occurs when the small amount of water is stopped is reduced, so that the water meter can be prevented from going too far.

[0011] Further, it is preferable that the set condition is such that, when accumulating the pressure when the small amount of water is stopped, the rising pressure is reduced and / or slowly increased. Accordingly, a sudden change in the inflow amount when the small amount of water is stopped can be similarly prevented, and the overrun phenomenon of the water meter can be reduced.

Further, it is preferable that the set condition is based on setting a long acceleration time of the soft start at the time of starting the pump after stopping the small amount of water. This allows
Similarly, it is possible to alleviate a sudden change in the inflow amount at the time of the small water amount stop operation, and to reduce the overrun phenomenon of the flusher.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an example of the configuration of a water supply device that is a premise of the embodiment of the present invention, and the configuration of each device is as described above. FIG. 2 is a diagram showing a discharge pressure, a flow rate, and the like at the time of a small water volume stop operation.

[0014] First, the excessive movement phenomenon of the water meter does not occur during the operation of the normal supply water amount of the pump. This occurs during a time period when the amount of used water is extremely reduced, such as at night, for example, and it is known that this occurs with a small water amount stop operation. In FIG. 2, when the discharge flow rate and the inflow flow rate up to time t1 match, these water amounts are the same, and there is no particular problem. The case where this flow rate is lower than the flow rate at which the pump performs the small water volume stop operation becomes a problem when it is continued for a long time.

For example, when the flow switch 20 operates at a rate of about 10 L / min or less, a small water amount stop operation is started after a predetermined detection time has elapsed. In this case, the pump speed is set to 0 at time t1, and the pump is stopped. However, since the water flow continues at the end of the customer although the amount of water is very small, the water stored in the pressure tank 16 is supplied, and the discharge flow rate does not change. Then, the discharge-side pressure detected by the pressure sensor 17 gradually decreases as illustrated. Then, when the pump starting pressure p1 is reached, the pump is started by a soft start. After the pump stops at time t1, the inflow flow rate becomes zero, but when the pump starts, the inflow flow rate suddenly increases. However, since the end customer is almost in a closed state, the pressure tank is mainly stored.

When the pump is started, the rotation speed is increased to secure the pressure on the discharge side. At this time, the pressure is accumulated in the pressure tank more than the required flow rate on the discharge side, and the amount of water on the inflow side increases, as shown in the figure. The inflow flow rate is pulsed, and at this time, the discharge pressure overshoots the predetermined pressure p2. For this reason, the inflow flow rate once becomes zero until time t3 after accumulating pressure in the pressure tank, becomes a steady state with the recovery of the overshoot state, the pump is operated at a predetermined rotation speed, and the discharge flow rate and the inflow flow rate are the same although the water volume is extremely small. The operation is continued in the state where it has become. Therefore, it is considered that the impeller of the water meter idles due to inertia due to the pulse-like change of the inflow flow rate during such a small water volume stop operation, and an overrunning phenomenon occurs.

FIG. 3 to FIG. 6 show various means for reducing such an excessive traveling phenomenon. 3A and 3B show the frequency of occurrence of the low water volume stop operation. FIG. 3A shows the frequency of the conventional low water volume stop operation, and FIG. 3B shows the low water volume stop operation in an improved state. Indicates the occurrence frequency of the operation. As described above, the excessive progress of the water meter is caused by the operation of stopping the small amount of water. Therefore, by reducing the frequency of occurrence, the excessive amount of the water meter can be reduced in proportion thereto. The frequency of occurrence of the low water volume stop operation is reduced by first detecting that the flow switch is in the low water volume state, and then confirming that the low water volume stop state will continue even after a predetermined time has elapsed, and then stopping the low water volume stop operation. Since the state is entered, the frequency of the small water amount stop operation can be reduced by lengthening the set time of the detection timer. Further, the delay timer is operated so as to operate for a certain period even if the low water amount state is detected again when the pump is restarted after the low water amount stop. By increasing the set time of the delay timer, the occurrence frequency of the small water volume stop operation can be similarly reduced. FIG. 3B shows a case in which the frequency of the low water amount stop operation is reduced to about half by such measures.

FIG. 4 shows a case where the pressure tank is made smaller. FIG. 4A assumes that the size of the conventional pressure tank 16 is, for example, about 20 L. In this case, the inflow rate is
As described above, the pulse shape is obtained. Then, FIG.
Is a case where the capacity of the pressure tank 16 is reduced to, for example, about 10 L. By doing so, FIG.
As shown in (b), the height of the pulse of the inflow flow rate is reduced, whereby the overrun phenomenon of the water meter can be reduced.

FIG. 5 shows a case in which after the detection of the small amount of stopped water, the pressure is further increased to perform the pressure accumulation operation. In the figure, a dotted line indicates a conventional method, and a solid line indicates an embodiment of the present invention. Time t1
When the pressure accumulating operation is started, the rotation speed of the pump 11 is increased, the discharge pressure of the conventional water head of about 5 to 7 m is increased in about 3 seconds, and the operation is continued for a predetermined time. At this time, as the inflow flow rate is such that water is accumulated in the pressure tank 16, it flows in a pulse shape as shown in FIG. 5B. In the embodiment of the present invention, the upper pressure increase during the pressure accumulation operation is reduced to about 3 m. Then, the pressure accumulation is performed slowly. For example, the discharge pressure is slowly increased over, for example, about 30 seconds, whereas the discharge pressure is conventionally increased within about 3 seconds. Even if the water is slowly raised in this way, since little water is used on the consumer side, there is almost no effect on the consumer side. By doing so, as shown in FIG. 5B, the peak of the pulse of the inflow flow rate becomes lower, thereby reducing the overrun phenomenon of the water meter. It should be noted that reducing the upper pressure increase during the pressure accumulation operation and slowly increasing the discharge pressure during the pressure accumulation operation may be performed independently of each other, or both may be used in combination.

FIG. 6 shows a countermeasure by setting a longer acceleration time when restarting the pump after stopping the small amount of water. In the figure, a dotted line indicates a conventional method, and a solid line indicates a method according to the present embodiment. When a small amount of water is detected by the flow switch 20, the speed of the pump is set to zero at time t1 after the operation for a predetermined time has elapsed, and the operation of the pump is stopped. Then, the discharge pressure gradually decreases, and when the pressure reaches the pressure p1, the pump is restarted.
At this time, the pump speed increased conventionally, for example, about 1 second as shown by a dotted line in the figure. The time required for the pump speed to rise to the target discharge pressure is increased to about 3 seconds as shown by the solid line in the figure. By doing so, the peak of the pulse is remarkably reduced as shown in the flow rate of the inflow stored in the tank when the pump is restarted, and the steady state is continuously achieved. As a result, the overrun phenomenon of the water meter is significantly reduced. The discharge pressure smoothly reaches the target discharge pressure without overshooting. In addition, since the water is supplied from the pressure tank 16 to the end customer side even when the pump is stopped, a fixed amount is supplied regardless of the operation stop state of the pump. By eliminating the overshoot of the discharge pressure at the start of the pump in this way, the water meter can be effectively prevented from excessively moving. However, the PI control gain of the pump operation speed control system is reduced or the integral value is reduced. Similarly, smooth restart of the pump can be performed by taking measures such as raising the pressure.

Although examples of countermeasures for suppressing the excessive movement of various water meters have been described above, it is needless to say that the excessive phenomenon can be further suppressed by using a combination or a modified example thereof. is there.

[0022]

As described above, according to the present invention,
In a water supply device directly connected to a water main or the like, even when a water meter is installed on the inflow side of the water supply device, it is possible to prevent an excessive phenomenon of the water meter and accurately accumulate the used water amount.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a water supply device.

FIG. 2 is a diagram illustrating a discharge pressure, a discharge flow rate, an inflow flow rate, and a pump speed during a small water amount stop operation.

FIG. 3 is a diagram showing the frequency of occurrence of a small water volume stop operation;
(A) shows a conventional example, and (b) shows an embodiment of the present invention.

FIG. 4 is a diagram showing an inflow flow rate during a low water volume stop operation;
(A) shows a case where a conventional normal-sized pressure tank is adopted, and (b) shows a case where a small-capacity pressure tank according to the embodiment of the present invention is adopted.

5A and 5B are diagrams showing (a) discharge pressure and (b) inflow flow rate during a low-water-volume stop operation, in which a dotted line indicates a conventional upward pressure-increasing and speed-accumulating operation, and a solid line in the diagram indicates the present invention. Fig. 3 shows an operation of accumulating pressure at an upper pressure and a speed in the embodiment.

FIG. 6 is a diagram showing a discharge pressure, a discharge flow rate, an inflow flow rate, and a pump speed at the time of a small water amount stop operation, and a dotted line in the figure shows an example of a conventional acceleration time when the pump is restarted, and a solid line in the figure. Shows an example of the acceleration time when the pump is restarted according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Pump 12 Inflow pipe 13 Discharge pipe 15 Check valve 16 Pressure tank 17, 18 Pressure sensor 19 Control panel 20 Flow switch 21 Inlet side water meter 22 Customer side water meter

Continued on the front page (72) Inventor Kaoru Yagi 11-1 Haneda Asahimachi, Ota-ku, Tokyo F-term in Ebara Corporation (reference) 2F030 CC02 CD20 CE12 CF05 CF07 CF08 CF20 3H045 AA09 AA12 AA23 BA00 BA03 BA07 BA22 CA02 CA03 CA06 DA01 DA05 EA13 EA14

Claims (5)

[Claims] 1. A water supply device provided with a water meter on an inflow side, which pressurizes water measured by the water meter using a pump and sends the water to end-users, wherein the water supply device uses an extremely small amount of water. It is provided with a small water volume stop function for stopping the operation of the pump when the water volume is reached, and the small water volume stop function is provided with a setting condition for suppressing an excessive phenomenon of the water meter provided on the inflow side. Water supply device. 2. The water supply device according to claim 1, wherein the setting condition is to reduce the frequency of occurrence of a small water amount stop operation. 3. The water supply apparatus according to claim 1, wherein the set condition is that the capacity of a pressure tank that accumulates pressure when a small amount of water is stopped is reduced. 4. The water supply apparatus according to claim 1, wherein the set condition is such that when accumulating pressure when the small amount of water is stopped, the rising pressure is reduced and / or slowly increased. 5. The water supply device according to claim 1, wherein the set condition is such that a soft start acceleration time is set to be long when the pump is started after a small amount of water is stopped.