JP4664019B2 - Water supply equipment - Google Patents

Description

  The present invention relates to a water supply apparatus, and more particularly to a direct connection type water supply apparatus that is directly connected to a water main and supplies the tap water of the water main to a terminal customer.

  FIG. 1 is a schematic diagram showing a conventional directly connected water supply device 500. As shown in FIG. 1, a conventional directly connected water supply apparatus 500 includes a plurality of pumps 502, a motor 504 that drives the pump 502, an inverter 506 that controls the rotational frequency of the motor 504, and an inverter 506. And a control unit 508 for controlling various devices. These pumps 502 are connected to an upstream water supply pipe 512 extending from the water main pipe 510 via a pump suction pipe 514, and connected to a downstream water supply pipe 516 extending to a water supply terminal of a consumer such as a building or an apartment via a pump discharge pipe 518. Connected.

  This water supply apparatus 500 includes a bypass pipe 520 connected to an upstream water supply pipe 512 and a downstream water supply pipe 516. The bypass pipe 520 is provided with a check valve 522 for preventing water from flowing backward from the downstream water supply pipe 516 side to the upstream water supply pipe 512 side. The pump discharge pipe 518 has a check valve 524 for preventing water from flowing back from the discharge side to the suction side when the pump 502 is stopped, and detects that the amount of water in the pump discharge pipe 518 has decreased. A flow switch 526 is provided. The output of the flow switch 526 is input to the control unit 508.

  The pump discharge pipe 518 and the bypass pipe 520 on the discharge side of the pump 502 are joined to one downstream water supply pipe 516, and the downstream water supply pipe 516 is provided with a pressure sensor 528 for detecting the discharge pressure of the pump 502. Yes. An output signal of the pressure sensor 528 is input to the control unit 508. In addition, a pressure tank 534 is connected to the downstream water supply pipe 516, and when the flow switch 526 detects that the amount of water has decreased, the pressure tank 534 is connected to the pump tank 502 in order to prevent the shutoff operation of the pump 502. After accumulating pressure, the operation of the pump 502 is stopped.

  The upstream water supply pipe 512 is provided with a backflow prevention device 530 that prevents the water on the pump 502 side from flowing back to the water main pipe 510. A pressure sensor 532 that measures the pressure in the upstream water supply pipe 512 is provided on the upstream side of the backflow prevention device 530, and an output signal of the pressure sensor 532 is sent to the control unit 508.

  In the directly connected water supply apparatus 500 having such a configuration, the rotation speed (rotation frequency) of the pump 502 is variable-speed controlled by the inverter 506 based on output signals from the pressure sensors 528 and 532 and the flow switch 526.

  That is, when the discharge pressure detected by the pressure sensor 528 drops below a preset starting pressure due to the use of water by the consumer, one of the pumps 502 is started. Based on the outputs of the two pressure sensors 528 and 532, the terminal pressure constant control or the discharge pressure constant control is performed by the control unit 508. When the suction pressure detected by the pressure sensor 532 becomes high enough to satisfy the target pressure without operating the pump 502, the operation of the pump 502 is stopped. Thereafter, when the discharge pressure detected by the pressure sensor 528 falls below the above-described starting pressure, the pump 502 is started again. In this case, the pump 502 is switched to the other pump 502 and the operation time of each pump 502 is changed. Averaged.

  Further, when the flow switch 526 is turned on during the operation of the pump 502, it is determined that the water is not used and the amount of water is small, and the operation of the pump 502 is stopped. In this state, when the use of water is detected due to a decrease in the discharge pressure or the like, the pump 502 is restarted as described above.

  Such conventional directly connected water supply systems are intended for large buildings such as relatively high-rise apartment buildings and buildings where boosting up with large pumps is indispensable. In order to connect directly to water outage, it is essential to have a backup function with multiple pumps. For this reason, the conventional water supply apparatus 500 includes a plurality of pumps 502. When an abnormality of a specific pump 502 or inverter 506 is detected during operation, the other normal pump 502 or inverter 506 is The operation is switched to continue water supply.

  However, in a relatively low-rise, small-scale apartment house of about 3 to 5 floors, in most cases, it is possible to supply water to the end demand destination only by the pressure of the water main 510. For such buildings as well, it is often the case that a directly connected water supply apparatus as described above is installed assuming that the water supply pressure on the upper floor is rarely insufficient due to the pressure drop of the water main 510. However, since it is usually possible to supply water to the end demand destination only by the pressure of the water main pipe 510, it is rare that the pump is operated. Therefore, the direct connection type water supply apparatus provided with a plurality of conventional pumps is a heavy burden in terms of cost and installation location.

  In addition, when the above-described conventional directly-connected water supply apparatus 500 is used in a relatively low-rise, small-scale housing complex, water supply is performed through the bypass pipe 520 with almost no operation of the pump 502. The check valve 522 provided in the pipe 520 always causes a pressure loss.

  Further, in the conventional direct-coupled water supply apparatus, in order to measure the pressure in the upstream water supply pipe 512, it is necessary to provide the upstream water supply pipe 512 with a relatively expensive pressure sensor 532, and this pressure sensor 532 increases the cost. Invited. Furthermore, considering the convenience of users of tap water, it is desirable that maintenance such as pump replacement is possible without interrupting water supply as much as possible.

  The present invention has been made in view of such problems of the prior art, and can reduce the introduction cost and running cost of the apparatus, and is particularly suitable for water supply to a relatively low-rise building with a small scale. An object is to provide a directly connected water supply device.

According to one aspect of the present invention, there is provided a directly connected water supply apparatus that can be suitably used for supplying water to a relatively low-rise building with a small scale. The water supply apparatus includes a bypass pipe that connects an upstream water supply pipe extending from the water main and a downstream water supply pipe extending to a demand destination, and a single pump that is driven when the pressure of the upstream water supply pipe decreases. Yes. In addition, the water supply device includes a pump suction pipe connecting the upstream water supply pipe or a bypass pipe near the upstream water supply pipe and a suction port of the pump, a discharge port of the pump, and the downstream water supply pipe or the vicinity of the downstream water supply pipe. And a pump discharge pipe connected to the bypass pipe. Further, the water supply device includes an on-off valve that opens and closes a flow path of the bypass pipe located between the pump suction pipe and the pump discharge pipe, a pressure sensor that measures a discharge pressure of the pump, the pump, and the pump And a control unit for controlling the on-off valve. The controller starts the pump and closes the open / close valve when the discharge pressure of the pump becomes equal to or lower than the pump start pressure set to a value lower than the normal pressure of the water pipe. In addition, as a pump, it is preferable to use an efficient pump when there is a low head and a relatively high flow rate.

  For relatively low-rise, small-scale apartments, etc., in most cases, water can be supplied only by the pressure of the water main, so in normal times, water is supplied to the customer through the bypass pipe, and the water main is When the pressure of the water drops, water can be supplied to the customer by a single pump. Thus, according to the water supply apparatus which concerns on this invention, since only one pump is required, the introduction cost and running cost of an apparatus can be reduced.

  In addition, if the water mains pressure is restored, the pump is surely stopped regardless of the amount of water used at the customer. Therefore, detection means such as a flow switch for detecting that the amount of water used is small and stopping the pump becomes unnecessary, and the cost of the apparatus can be reduced. Further, since sufficient water supply is possible with the pressure of the water main even when the pump is stopped, a pressure tank for supplying water when the amount of water used is small and the pump is stopped can be eliminated. Therefore, the apparatus can be reduced in size and cost. Further, according to the present invention, it is not necessary to measure the pressure in the upstream water supply pipe, so that it is not necessary to attach a relatively expensive pressure sensor, and the cost of the apparatus can be reduced.

Furthermore, when a check valve is used as in the prior art, it is necessary to supply water against the check valve when water is supplied by the bypass pipe. However, by using an on-off valve as described above, Sometimes it is not necessary to supply water against the check valve, and pressure loss can be reduced.

When starting up the pump, the pump will close the opening and closing valve before starting to drive, it means that would increase the pressure loss by further off valve in a state where the water supply pressure is insufficient, the control The part preferably controls the on-off valve so as to close the flow path after the pump starts to be driven.

In addition, when the on / off valve is opened after the pump is completely stopped when the pump is stopped, since the pressure loss until the on / off valve opens is large, the control unit stops the pump completely. It is preferable to control the on-off valve so as to open the flow path before.

Furthermore, the control unit preferably controls the on-off valve to open the flow path when the water supply device is stopped.

  Instead of the on-off valve, a three-way valve may be arranged at the connection between the pump suction pipe and the upstream water supply pipe or the bypass pipe or at the connection between the pump discharge pipe and the downstream water supply pipe or the bypass pipe. Good.

The water supply device has a pressure sensor for detecting the discharge pressure of the pump, and when the discharge pressure detected by the pressure sensor is equal to or lower than the starting pressure set to a value lower than the normal pressure of the water main. and Nde including a control unit for driving the pump. After the pump is started , the control unit continues the state where the discharge pressure is lower than the normal pressure of the water main and higher than the target pressure set to a value higher than the starting pressure for a certain time or more. It is preferable to stop the pump when it does .

  The bypass pipe is preferably formed linearly. Thus, by forming the bypass pipe in a straight line, the pressure loss due to the water flow when water is supplied through the bypass pipe can be minimized.

  Further, a pressure switch may be arranged on the upstream side of the connection portion between the pump suction pipe and the upstream water supply pipe or the bypass pipe. By appropriately setting the operating pressure of this pressure switch, the operation of the pump can be stopped when the pressure of the water main pipe is greatly reduced for some reason.

  It is preferable that the water supply device further includes a gate valve that blocks the flow paths in the pump suction pipe and the pump discharge pipe. Since the pump can be separated from the bypass pipe by closing each gate valve, maintenance such as replacement of the pump can be performed without interrupting the water supply through the bypass pipe.

  ADVANTAGE OF THE INVENTION According to this invention, the introduction cost and running cost of an apparatus can be reduced, and water supply can be effectively implement | achieved especially to a building with a comparatively low floor and a small scale.

  Hereinafter, embodiments of a water supply apparatus according to the present invention will be described in detail with reference to FIGS. 2 to 9. 2 to 9, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.

  Drawing 2 is a mimetic diagram showing water supply device 1 in a 1st embodiment of the present invention. This water supply apparatus 1 can be suitably used for a relatively low-rise, small-scale housing complex, etc., and when it is possible to supply tap water to an end demand destination only at the pressure (normal pressure) of the water main 2 at normal times. Applied. As shown in FIG. 2, the water supply device 1 includes a device main body 16 having one pump 10, a motor 12 that drives the pump 10, and a control unit 14 that controls the motor 12 and other devices. Yes. The apparatus main body 16 is connected to an upstream water supply pipe 18 extending from the water main pipe 2 and a downstream water supply pipe 20 extending to a water supply terminal of a consumer.

  The apparatus main body 16 includes a bypass pipe 22 connected to the upstream water supply pipe 18 at the inlet 16a and to the downstream water supply pipe 20 at the outlet 16b. In the vicinity of the upstream water supply pipe 18 of the bypass pipe 22, a pump suction pipe 24 connected to the suction port of the pump 10 is attached via a gate valve 26, and in the vicinity of the downstream water supply pipe 20 of the bypass pipe 22. The pump discharge pipe 28 connected to the discharge port of the pump 10 is attached via a gate valve 30.

  The control unit 14 displays an inverter 32 that controls the rotational frequency (rotational speed) of the motor 12 at a variable speed, a controller 34 that controls various devices including the inverter 32, and an operating state of the water supply device 1. A display operation unit (not shown) for performing various settings such as input of operating conditions is provided.

  The upstream water supply pipe 18 on the upstream side of the apparatus main body 16 prevents the backflow of tap water from the apparatus main body 16 to the water main pipe 2 and prevents contamination of the tap water in the water main pipe 2. 36 is provided. As such a backflow prevention mechanism 36, a double check valve, a pressure reduction type backflow preventer, or the like can be used. Alternatively, a check valve may simply be used as the backflow prevention mechanism 36. A pressure switch 38 that operates when the water pressure in the upstream water supply pipe 18 reaches a predetermined pressure is provided on the upstream side of the backflow prevention mechanism 36. The output signal of the pressure switch 38 is sent to the controller 34 of the control unit 14.

  The pump discharge pipe 28 in the apparatus main body 16 is provided with a pressure sensor 40 that measures the water pressure (discharge pressure) in the pump discharge pipe 28. The output signal of the pressure sensor 40 is sent to the controller 34 of the control unit 14. Further, the bypass pipe 22 in the apparatus main body 16 is provided with an automatic opening / closing valve 42 for opening and closing a flow path located between the pump suction pipe 24 and the pump discharge pipe 28. The automatic opening / closing valve 42 is controlled to be opened / closed by a signal from the controller 34 of the control unit 14.

  The automatic opening / closing valve 42 is configured to automatically open the flow path when the water supply apparatus 1 stops due to a power failure or the like. Further, even when the inverter 32 is tripped or the pump 10 is broken, the automatic opening / closing valve 42 is opened. In these cases, the pump activation is retried after a predetermined time has elapsed, and when the pump 10 is normally activated, the automatic opening / closing valve 42 is closed.

  As described above, during normal times, sufficient water can be supplied to the customer by the pressure of the water main 2 (normal pressure), so the pump 10 of the water supply apparatus 1 is stopped, and the automatic open / close valve 42 of the bypass pipe 22 is stopped. Is open. Therefore, the tap water in the main water pipe 2 is mainly supplied to the terminal customer through the upstream water supply pipe 18, the bypass pipe 22, and the downstream water supply pipe 20. A part of the tap water passes through the pump suction pipe 24, the pump 10, and the pump discharge pipe 28 and reaches the downstream water supply pipe 20.

  Here, if the pressure of the water main 2 is slightly reduced due to an increase in the amount of water supply in the area, the pressure of the water main 2 alone is not sufficient to secure sufficient water supply at the high-end demand destination. It may become. In such a case, the pressure sensor 40 provided in the pump discharge pipe 28 detects that the pressure has fallen below a preset starting pressure, and in response to this, the controller 34 of the control unit 14 starts the pump 10. At the same time, the automatic open / close valve 42 provided in the bypass pipe 22 is closed. In this case, if the automatic open / close valve 42 is closed before the pump 10 starts to drive, the pressure loss is further increased by the automatic open / close valve 42 in a state where the feed water pressure is insufficient. It is preferable to close the automatic open / close valve 42 after the motor starts to drive.

  At this time, the pump 10 is soft-started in order to suppress fluctuations in the pressure of the water main pipe 2, but the automatic opening / closing valve 42 is not closed rapidly but is slowly closed over a period of 1 to 3 seconds. It is preferable. In addition, by taking time for the closing in this way, it is possible to smoothly shift to the water supply by the operation of the pump 10 without causing a sudden pressure change by the pressure control of the pump 10.

  After the pump 10 is started, the rotation speed of the pump 10 is controlled by the inverter 32 so that the pressure detected by the pressure sensor 40 matches the set target pressure, so that the discharge pressure of the pump 10 becomes constant. The discharge pressure constant control is performed. Thus, in this embodiment, although discharge pressure constant control is performed, since it is thought that the time which the pump 10 should be operated by the fall of the pressure of the water main pipe 2 is short, the supply water pressure in the terminal demand destination is There is almost no problem with respect to energy saving even if the terminal pressure constant control for controlling the constant pressure is not performed. Needless to say, the terminal pressure constant control may be performed by appropriately changing the target value of the discharge pressure of the pump 10.

  During operation of the pump 10, it is necessary to prevent water pressurized by the pump 10 from flowing back through the bypass pipe 22 and returning to the upstream water supply pipe 18 side. It is also conceivable to provide However, when a check valve is used, it is necessary to supply water against the check valve when water is supplied by the bypass pipe 22 (when the pump 10 is stopped). In this embodiment, since the automatic open / close valve 42 is used without using the check valve, it is not necessary to supply water against the check valve when supplying water by the bypass pipe 22, and pressure loss can be reduced. .

  The starting pressure and target pressure of the pump 10 are set in the display operation unit of the control unit 14. These starting pressure and target pressure are stored in a memory (storage device) in the controller 34. The starting pressure is set to a pressure at which a sufficient amount of water can be supplied at a demand destination at the highest position in the planned maximum water supply amount, or a pressure slightly lower than that. The target pressure is set to a value slightly higher than the starting pressure. Normally, sufficient water supply is possible only by the pressure of the water main 2, so both the starting pressure and the target pressure are set to values lower than the pressure (normal pressure) of the water main 2 at normal times.

  After the pump 10 is started as described above, when the pressure of the water main pipe 2 is recovered, the rotational speed of the pump 10 is gradually lowered and finally lowered to the minimum rotational speed. When the discharge pressure detected by the pressure sensor 40 is higher than the target pressure at this minimum rotational speed, the controller 34 recovers the pressure of the water main pipe 2 to the normal pressure (that is, the pump 10). The pump 10 is stopped and the automatic on-off valve 42 is opened.

  At this time, if the pump 10 is stopped, water is supplied only by the pressure of the water main pipe 2. However, if the automatic open / close valve 42 is opened after the pump 10 is completely stopped, the automatic open / close valve 42 is opened. Since the pressure loss between them is large, it is preferable to open the automatic opening / closing valve 42 before the pump 10 is completely stopped. Further, when the pump 10 is stopped, it is preferable that the automatic opening / closing valve 42 is slowly opened over a period of 1 to 3 seconds as in the case of starting the pump 10.

  In this way, the automatic open / close valve 42 is opened, the pump 10 is stopped, and water is supplied again only by the pressure of the water main pipe 2. Thus, in this embodiment, if the pressure of the water main 2 is recovered, the pump 10 is surely stopped regardless of the amount of water used at the demand destination. Therefore, detection means such as a flow switch (see reference numeral 526 in FIG. 1) for detecting that the amount of water used is small and stopping the pump 10 becomes unnecessary, and the cost of the apparatus can be reduced. Moreover, since sufficient water supply is possible with the pressure of the water main 2 even when the pump 10 is stopped, the water supply required when a conventional water supply device is small and the pump is stopped is provided. Therefore, a pressure tank (refer to reference numeral 534 in FIG. 1) can be eliminated. Therefore, the apparatus can be reduced in size and cost.

  Even when the pressure of the water main 2 is reduced and the pump 10 must be operated, it is not necessary to operate the pump 10 if water on the demand side is not used. Therefore, it is possible to provide a detection means for detecting whether or not water is used on the demand side, and to control the operation of the pump 10 when the water usage is low. For example, it is possible to detect an increase in the temperature of the pump 10 or piping to detect that the pump is in a shut-off operation, or to use a flow switch. In addition, even if the presence or absence of water use is not positively detected in this way, if the water usage on the demand side is excessive, as described above, the rotational speed of the pump 10 decreases to the minimum rotational speed. After a certain period of operation at the minimum rotational speed, the pump 10 is stopped.

  Here, when the pressure of the water main 2 is greatly reduced for some reason, the operation of the pump 10 of the water supply device 1 must be stopped from the viewpoint of preventing the inflow of sewage into the water main 2 and equality of water supply. . In the present embodiment, operation control of the pump 10 in such a case is performed by a pressure switch 38 provided upstream of the backflow prevention mechanism 36. In other words, the operating pressure of the pressure switch 38 is set to a pressure at which the operation of the pump 10 must be stopped from the viewpoints of preventing the inflow of sewage and the horizontal supply.

  That is, while the pressure of the water main 2 is greatly reduced, the pump 10 is operated unless the amount of water supplied to the demand side is 0, but when the pressure switch 38 is activated during the operation of the pump 10, the pressure switch 38 output signals are input to the controller 34 of the control unit 14. In response to this, the controller 34 stops the operation of the pump 10 and opens the automatic open / close valve 42 of the bypass pipe 22. Here, the reason why the automatic opening / closing valve 42 is opened is to secure water supply as much as possible even though the pump 10 cannot be operated. After that, when the pressure of the water main pipe 2 is recovered and exceeds the operation release pressure of the pressure switch 38, the controller 34 receiving the output signal starts the pump 10 and closes the automatic opening / closing valve 42.

  As described above, in a relatively low-rise, small-scale apartment house, water supply can be performed only by the pressure of the water main 2 in most cases. Moreover, even if the water supply pressure on the upper floor becomes insufficient due to a decrease in the pressure of the main water pipe 2, the time during which the water supply pressure is insufficient is considered to be very short. Accordingly, in the present embodiment, water is supplied through the bypass pipe 22 even when the pump 10 fails, so that even if there is only one pump 10, there is a practical problem until the pump 10 is repaired. There is hardly any.

  Further, as shown in FIG. 2, the bypass pipe 22 in the present embodiment is formed in a straight line from the inlet 16a to the outlet 16b of the apparatus body 16, and the pump suction pipe 24 and the pump discharge pipe 28 are formed in this straight line. It is the structure which branches and extends from the side-shaped bypass pipe 22 to the side. Thus, by forming the bypass pipe 22 in a straight line, the pressure loss due to the water flow when water is supplied through the bypass pipe 22 can be minimized. Note that the upstream water supply pipe 18 and the downstream water supply pipe 20 connected to the bypass pipe 22 may also be formed linearly.

  Further, according to the present embodiment, the pump 10 can be separated from the bypass pipe 22 by closing the two gate valves 26 and 30 at the time of maintenance of the pump 10 and the like. Maintenance such as replacement of the pump 10 can be performed without interrupting the water supply.

  Although FIG. 2 shows an example in which the pump suction pipe 24 and the pump discharge pipe 28 are branched from the bypass pipe 22, the pump suction pipe 24 may be branched from the upstream water supply pipe 18, and the pump discharge pipe 28 may be branched from the downstream water supply pipe 20.

  3 is a longitudinal sectional view showing an example of the structure of the apparatus main body 16 shown in FIG. 2, FIG. 4 is a plan view of FIG. 3, and FIG. 5 is a right side view of FIG. As shown in FIG. 3, each device in the apparatus main body 16 is arranged on a base 50 while being supported by a fixed leg (not shown), and these devices are covered with a cover 52. A transparent window 54 is provided on the upper portion of the cover 52. 2 shows an example in which the pressure sensor 40 is provided in the pump discharge pipe 28, but FIG. 3 shows an example in which the pressure sensor 40a is provided in the bypass pipe 22.

  As shown in FIG. 3 and FIG. 4, a display operation unit 56 for setting the above-described starting pressure of the pump 10 and displaying the operation status is disposed on the upper surface of the control unit 14 of the apparatus main body 16. The display operation unit 56 is exposed on the upper surface of the apparatus main body 16. Therefore, in the small apparatus main body 16, the operator can easily confirm the display on the display operation unit 56 and change the setting. The display operation unit 56 is located below the transparent window 54 so that the display content of the display operation unit 56 can be confirmed even with the cover 52 being kept. In addition, the display operation unit 56 in the present embodiment is configured so that the orientation can be changed according to the installation state of the apparatus main body 16, so that the convenience of the operator is not deteriorated. For example, as shown in FIG. 6, the display operation unit 56 can be rotated 180 degrees.

  7 is a longitudinal sectional view showing another example of the structure of the apparatus main body 16 shown in FIG. 2, and FIG. 8 is a plan view of FIG. In this example, the pump 10 is disposed above the bypass pipe 22. 2 shows an example in which the backflow prevention mechanism 36 is arranged outside the apparatus main body 16, but FIG. 7 shows an example in which the backflow prevention mechanism 36a is arranged inside the cover 52 of the apparatus main body 16. The control unit 14 including the display operation unit 56 is disposed above the backflow prevention mechanism 36a. In the example shown in FIGS. 7 and 8, since the width of the apparatus main body 16 can be reduced, the degree of freedom of the installation location is increased.

  FIG. 9 is a schematic diagram showing a water supply apparatus 101 according to the second embodiment of the present invention. This water supply apparatus 101 uses an automatic three-way valve 142 instead of the automatic opening / closing valve 42 of FIG. That is, an automatic three-way valve 142 is disposed at a connection portion between the pump suction pipe 24 and the bypass pipe 22, and the flow path is provided between the upstream water supply pipe 18, the bypass pipe 22, and the pump suction pipe 24 by the automatic three-way valve 142. It can be selected. When the pump 10 is operated, the automatic three-way valve 142 is controlled so that the tap water from the water main pipe 2 flows from the upstream water supply pipe 18 to the pump suction pipe 24, and when the pump 10 is not operated, The automatic three-way valve 142 is controlled so that the tap water flows from the upstream water supply pipe 18 to the bypass pipe 22.

  Although FIG. 9 shows an example in which the automatic three-way valve 142 is arranged at the connection portion between the pump suction pipe 24 and the bypass pipe 22, the automatic three-way valve 142 is arranged at the connection portion between the pump discharge pipe 28 and the bypass pipe 22. May be. In addition, when the pump suction pipe 24 is branched from the upstream water supply pipe 18, an automatic three-way valve 142 may be disposed at a connection portion between the pump suction pipe 24 and the upstream water supply pipe 18. Similarly, when the pump discharge pipe 28 is branched from the downstream water supply pipe 20, an automatic three-way valve 142 may be disposed at a connection portion between the pump discharge pipe 28 and the downstream water supply pipe 20.

  The pump 10 may be periodically operated at a low speed so as not to stagnate the water inside the apparatus. Moreover, also in 1st Embodiment mentioned above, the stagnation of water can be prevented by operating the pump 10 at a low speed with the automatic opening / closing valve 47 opened.

  Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea.

It is a schematic diagram which shows the conventional water supply apparatus. It is a schematic diagram which shows the water supply apparatus in the 1st Embodiment of this invention. It is a longitudinal cross-sectional view which shows an example of the structure of the apparatus main body shown in FIG. FIG. 4 is a plan view of FIG. 3. FIG. 4 is a right side view of FIG. 3. FIG. 5 is a partial plan view showing an example in which the direction of the display operation unit in FIG. 4 is changed. It is a longitudinal cross-sectional view which shows the other example of the structure of the apparatus main body shown in FIG. FIG. 8 is a plan view of FIG. 7. It is a schematic diagram which shows the water supply apparatus in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Water supply apparatus 10 Pump 12 Motor 14 Control part 16 Apparatus main body 16a Inlet 16b Outlet 18 Upstream water supply pipe 20 Downstream water supply pipe 22 Bypass pipe 24 Pump suction pipe 26, 30 Gate valve 28 Pump discharge pipe 32 Inverter 34 Controller 36 , 36a Backflow prevention mechanism 38 Pressure switch 40, 40a Pressure sensor 42 Automatic open / close valve 50 Base 52 Cover 54 Window 56 Display operation unit 142 Automatic three-way valve

Claims (6)

A bypass pipe connecting an upstream water supply pipe extending from a water main and a downstream water supply pipe extending to a demand destination;
A single pump that is driven when the pressure in the upstream feed pipe drops;
A pump suction pipe connecting the upstream water supply pipe or a bypass pipe near the upstream water supply pipe and the suction port of the pump;
A pump discharge pipe connecting the discharge port of the pump and the downstream water supply pipe or a bypass pipe near the downstream water supply pipe;
An on-off valve for opening and closing the flow path of the bypass pipe located between the pump suction pipe and the pump discharge pipe;
A pressure sensor for measuring the discharge pressure of the pump;
A controller that controls the pump and the on-off valve;
The control unit starts the pump and closes the on-off valve when the discharge pressure of the pump becomes equal to or lower than the starting pressure of the pump set to a value lower than the normal pressure of the water pipe. Water supply device. The water supply device according to claim 1 , wherein when the pump is started, the control unit controls the on- off valve so as to close the flow path after the pump starts to be driven. 3. The water supply device according to claim 1 , wherein when the pump is stopped, the control unit controls the on- off valve to open the flow path before the pump is completely stopped. 4. . The said control part controls the said on-off valve so that the said flow path may be opened when this water supply apparatus stops, The water supply apparatus as described in any one of Claim 1 to 3 characterized by the above-mentioned. The on-off valve, in that it consists of the pump suction pipe and the upstream water supply pipe or the bypass pipe and the connecting portion or the pump discharge pipe and the downstream water supply pipe or a three-way valve disposed in the connection portion between the bypass pipe The water supply apparatus according to claim 1, wherein After the pump is started , the control unit continues a state where the discharge pressure is lower than the normal pressure of the water main and higher than the target pressure set to a value higher than the starting pressure for a certain time or more. water supply apparatus according to any one of claims 1 to 5, wherein the benzalkonium stops the pump when.

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