JP5193896B2 - Water supply equipment - Google Patents

Description

  The present invention relates to a water supply apparatus using a pump driven by variable speed driving means.

  As an example of the prior art using a variable speed pump, there is Patent Document 1, for example. This patent document 1 is provided with two inverter devices 200, 200, and two pumps 411, 412 are driven at a variable speed to supply water by constant discharge pressure control.

  An example of performing pressure control using a pump as in Patent Document 1 will be described with reference to FIGS. 19-21 is a figure for demonstrating a pump characteristic. FIG. 19 shows a pump performance characteristic diagram in the operation range of one pump. In FIG. 19, the horizontal axis indicates the amount of water used, and the vertical axis indicates the water supply pressure and the load current value. Here, a curve Ca shows a water usage amount-feed water pressure characteristic curve when the pump is operated at a rotation speed of 100%. Curve Ia shows a water consumption-load current characteristic curve when the pump is operated at a rotation speed of 100%.

  Similarly, Cb and Ib are pumps at 90%, Cc and Ic are pumps at 80%, and Cd and Id are water usage-feed water pressure characteristic curves and water usage-load current characteristic curves when the pump is operated at 70%. Indicates.

  FIG. 20 is a diagram for explaining the operating characteristics of one pump in the estimated terminal pressure constant control. A curve Lr is a piping resistance curve such as valves and piping generated when water is pumped by the pump, and is a target value for controlling the discharge side pressure of the pump. For example, H00 is a target pressure when the amount of water is zero, that is, when water is not used on the demand side. The operating point at this time is indicated by the intersection of the pipe resistance curve Lr described above and the used water amount-water supply pressure characteristic curve Cmin at the time of operating one pump Fmin rotation speed.

  FIG. 21 is a diagram for explaining the operating characteristics of two pumps in the estimated terminal pressure constant control. Similarly to FIG. 20, the curve Lr indicates a pipe resistance curve, which is a target value for controlling the discharge side pressure of the pump. A curve Ca1 shows a water consumption-feed water pressure characteristic curve when one pump is operated at a rotation speed of 100%. Similarly, a curve Ca2 indicates a water consumption amount-feed water pressure characteristic curve when two pumps are operated at a rotation speed of 100%. By operating the second pump as necessary, it is possible to cope with a case where a higher pressure is required or a large amount of water is required.

  Since the operating point needs to be on the curve Lr in order to realize the estimated terminal pressure constant control, the range in which the estimated terminal pressure constant control is possible even if one pump is operated at 100% rotation speed is the curve Lr. And the intersection of Ca1, that is, the amount of water is up to Q100 and the water supply pressure is up to H100. Further, when water is used on the demand side, the amount of water used increases, but in this case, two pumps are operated.

JP 08-254195 A

  As described above, in the conventional water supply apparatus, pressure control using a plurality of pumps is disclosed so that water can be supplied even in a range where water cannot be supplied by one pump. When a plurality of pumps are used in a water supply device as in Patent Document 1, for example, water supply devices can be installed even when a high pressure or a large amount of water supply is required, such as installing a water supply device in a high building. . However, Patent Document 1 does not describe an operation method that is more efficient at the time of water supply.

  On the other hand, in pump control, it is necessary to consider the limit load current value of the pump in order to maintain reliability. The limit load current value of the pump means a maximum current value that can be used when there is a risk of failure due to excessive load when the pump is operated with a current higher than that applied to the motor. The above-mentioned Patent Document 1 does not disclose this point, and there is a risk that reliability may be reduced.

  An object of this invention is to provide a highly efficient water supply apparatus, maintaining reliability by operating in consideration of the limit load current value of a pump.

  In order to achieve the above object, in an embodiment of the present invention, a pump that is rotationally driven by an electric motor and variable speed means that drives the electric motor to a variable speed are provided, and the pump is rotationally driven to a variable speed. In the water supply system in which pressure control is performed by the pressure, an upper limit value is set for the current flowing to the motor, and the pump can be operated from the upper limit value of the current and the water amount-feed water pressure curve and the water amount-load current curve for each pump frequency. A range is determined.

In this aspect, further preferred embodiments are as follows.
(1) The water volume-feed water pressure curve of the pump changes according to the performance of the pump, and the operable range of the pump becomes wider as the curve indicated by the water volume-feed water pressure curve becomes gentler.
(2) A target pressure corresponding to the amount of water used is set in advance, and an upper limit value of the pump frequency is set based on the target pressure and the operable range.
(3) The target pressure is set by a piping resistance curve obtained in advance, and the estimated terminal pressure constant control is performed by controlling the pump frequency so that the operating point is on the piping resistance curve.

  In another embodiment of the present invention for solving the above object, a plurality of pumps driven to rotate by an electric motor, variable speed means for driving the motor to a variable speed, and the pump being driven to rotate at a variable speed. Thus, in the water supply apparatus in which pressure control is performed, an upper limit value of the frequency is set for the pump, and the upper limit value of the frequency is set to be larger as the number of operating pumps increases.

In this aspect, further preferred embodiments are as follows.
(1) The operable range of the pump changes due to the change in water volume-feed water pressure characteristics depending on the number of pumps operated.
(2) An upper limit value is set for the current flowing to the motor, and the operable range of the pump is determined from the upper limit value of the current, the water amount-feed water pressure curve and the water amount-load current curve for each pump frequency.
(3) A target pressure corresponding to the amount of water used is set in advance, and an upper limit value of the pump frequency is set based on the target pressure and the operable range.
(4) The target pressure is set by a pipe resistance curve obtained in advance, and the estimated terminal pressure constant control is performed by controlling the pump frequency so that the operating point is on the pipe resistance curve.

  According to the above means, it is possible to provide a highly efficient water supply device while maintaining reliability.

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

The 1st Example of the water supply apparatus by this invention is described using FIGS.
FIG. 1 shows a configuration diagram of a water supply system. 8-1, 8-2, 8-3, 8-4 are a plurality of pumps driven by a plurality of motors 9-1, 9-2, 9-3, 9-4, respectively. From the smaller one, it is called No. 1 pump, No. 1 motor, No. 2 pump, No. 2 motor, No. 3 pump, No. 3 motor, No. 4 pump, No. 4 motor. The suction side of these pumps is connected to the water source side via a suction pipe 11. The water source is supplied with water from a water main that is not shown in the direct connection system. In the water tank system, water is supplied from a water tank (not shown). 12-1, 12-2, 12-3, 12-4 are check valves, 13-1, 13-2, 13-3, 13-4 and 14-1, 14-2, 14-3, 14 respectively. -4 is a gate valve, 15 is a water supply pipe, and 16 is a pressure sensor that is provided in the water supply pipe 15 and generates an electrical signal in accordance with the pressure. Based on the pressure detection of this sensor, the pump discharge pressure is controlled to be constant at the estimated end pressure. Reference numeral 17 denotes a pressure tank, which is provided at a location near the pump of the water supply pipe 15. Further, as the demand side, the end of the water supply pipe 15 is connected to the demand side water supply pipe to supply water to a faucet of an apartment house, for example.

  Reference numerals 1-2, 2-2, 3-2, and 4-2 denote main bodies of inverters that drive the motors 9-1, 9-2, 9-3, and 9-4, respectively. A control board 1-1, which is supplied with power from the power supply side via the earth leakage breakers ELB 1, ELB 2, ELB 3 and ELB 4, respectively, and includes a microprocessor MCU 1-2, MCU 2-2, MCU 3-2 and MCU 4-2, respectively. The inverter main body is driven and controlled by 2-1, 3-1, and 4-1. These control boards include a display unit and an operation unit, and an ID No. And memories M01 to M04 (for example, EEPROM) for storing pressure control, number control, parameters for starting and stopping, pressure signals detected by the pressure sensor, and the like.

  The interface board I / O is supplied with power through the control power circuit breaker CP, and is connected to the microprocessor MCU4, IDNo. , Pressure control, number control, parameters for starting and stopping, pressure signal detected by the pressure sensor, memory M05 (for example, EEPROM), display unit SC, operation unit T, operation mode selection switch MODSW, discharge as described above A side pressure sensor input terminal I1 is provided.

  Further, each inverter main body and the control board are connected by communication signal lines S1 to S4, and each control board and the inverter main body are driven, controlled and monitored by the above-described signal lines S1 to S4. The interface board I / O and each control board are connected by communication signal lines S5 to S8 and S9. For example, RS485 is used for communication control.

  As shown above, FIG. 1 shows an example of four sets, but this can be expanded to constitute an n-type water supply system. Here, each control board, inverter main body, and interface board are equipped with a microprocessor, and these are connected by communication signal lines to exchange information.

Next, the case of performing pressure control using a pump will be described with reference to the drawings.
FIG. 2 is a diagram showing the characteristics of one pump. The horizontal axis indicates the amount of water used, and the vertical axis indicates the supply water pressure and the load current value. Here, a curve Ca shows a water usage amount-feed water pressure characteristic curve when the pump is operated at a rotation speed of 100%. A curve Ia shows a water consumption-load current characteristic curve when the pump is operated at a rotation speed of 100%. Similarly, Cb and Ib are pumps at 90%, Cc and Ic are pumps at 80%, and Cd and Id are water usage-feed water pressure characteristic curves and water usage-load current characteristic curves when the pump is operated at 70%. Indicates.

  Here, in this embodiment, a limit load is given to the operation range in order to improve the reliability. As the limit load, Im in FIG. 2 indicates a limit load current value of the pump, and if the operation is performed for a long time exceeding the current value, it may cause a failure of the pump.

  Therefore, when operating at a rotational speed of 100%, the operation range is up to the water amount Qa at point A, which is the intersection of Ia and Im, and the water supply pressure at that time is Ha. Similarly, when operating at a rotation speed of 90%, Qb and Hb, and when operating at a rotation speed of 80%, the operation amount ranges from Qc and Hc to the amount of water and water supply pressure. Therefore, water supply by one pump is possible only in the range surrounded by the curve Ip connecting the pressure axis and the water amount axis, the curves Ca, and A ′, B ′, and C ′.

  FIG. 3 is a diagram for explaining the operating characteristics of one pump in the estimated terminal pressure constant control. In addition, Ip calculated in consideration of the limit load current value of the pump described in FIG. 2 is also shown. A curve Lr is a piping resistance curve such as valves and piping generated when water is pumped by the pump, and is a target value for controlling the discharge side pressure of the pump. For example, H00 is the target pressure at the point where the amount of water is 0, and is indicated by the intersection of the pipe resistance curve Lr described above and the used water amount-water supply pressure characteristic curve Cmin when operating at one pump Fmin rotation speed.

  As described in FIG. 2, the water supply possible range with one pump is a region surrounded by the pressure axis, water amount axis, Ca, and Ip, so that the maximum water amount that satisfies the target pressure is Q00i, which is the intersection of Lr and Ip, The total head is H00i. The operation frequency at this time is a frequency upper limit value in pump control in consideration of the limit load current value of the pump, and one pump cannot operate at a frequency exceeding this value. The pump performance curve at the frequency upper limit value at this time is a curve indicated by a curve Cmax.

  Next, the case where the estimated terminal pressure constant control is performed using two pumps will be described with reference to FIG. FIG. 4 shows an operation characteristic diagram of two pumps in this case. Similarly to FIG. 3, the curve Lr indicates a pipe resistance curve, and in the estimated terminal pressure constant control, the control is performed so that the discharge side pressure of the pump becomes above this Lr. Here, the curve Ca1 shows a water consumption-water supply pressure characteristic curve when one pump is operated at a rotation speed of 100%. Similarly, a curve Ca2 indicates a water consumption amount-feed water pressure characteristic curve when two pumps are operated at a rotation speed of 100%.

  As shown in FIG. 4, as the number of pumps increases, the used water amount-feed water pressure characteristic curve representing the characteristics becomes a gentle curve. This is the same when the capacity of the pump is increased. Theoretically, it is possible to have the performance of the used water amount-feed water pressure characteristic curve Ca2 shown in FIG. 4 with one pump. In this embodiment, it is assumed that the performance of one pump has a characteristic drawn by a Ca1 used water amount-feed water pressure characteristic curve when operated at a frequency of 100%.

  Here, Ip1 is a curve showing a range in which one pump can be operated, which is obtained in consideration of the limit load current value of the pump described in FIG. Therefore, in consideration of this Ip1, the upper limit of the operable frequency when the estimated terminal pressure constant control is performed with one pump is not the rotation speed of 100% indicated by the curve Ca1, but the frequency Fmax obtained from the intersection of Ip1 and Lr. Become. That is, Cmax1 indicates a water usage-water supply pressure characteristic curve when one pump is operated at the frequency upper limit value Fmax1 in the control considering the limit load current value of the pump.

  Next, Cmax2 shows a water consumption-feed water pressure characteristic curve when two pumps are operated at this frequency Fmax1. In this case, when the estimated terminal pressure constant control is performed, the water amount and the feed water pressure are indicated by the intersection of the used water amount-feed water pressure characteristic curve Cmax2 and the pipe resistance curve Lr, the water amount is Q02, and the feed water pressure is H02. Become.

  Here, a characteristic pump control method of this embodiment will be described. In FIG. 4, Ip2 indicates a range where two pumps can be operated in consideration of the limit load current value of the pump. In FIG. 2, Ip (Ip1 in FIG. 4) indicating the operable range of one pump was obtained from the limit load current value Im of the pump. Although not shown in detail in FIG. 4, the operable range Ip2 of the two pumps can be obtained in consideration of the limit load current value Im from the same concept. As shown in FIG. 4, the operable range Ip2 has a smaller absolute value of inclination than Ip1, and is further shifted to the right side of the figure.

  As described above, in order to realize the estimated terminal pressure constant control, the operating point needs to be on the pipe resistance curve Lr. Then, since the inclination of Ip2 is larger and shifted to the right side, it can be seen that the range in which the operating point is on the piping resistance curve Lr has expanded. When one pump is operated as described above, the frequency upper limit value is Fmax1 in consideration of the limit load current value. However, the water amount Q02 and the feed water pressure H02 when both pumps are operated at this Fmax It is inside the operable range Ip2. That is, in this case, unlike the case of one pump, there is a margin in the load current of the pump.

  Therefore, in this embodiment, when operating with two pumps, the frequency upper limit value is set to Fmax2 larger than the frequency upper limit value Fmax1 of one pump. This Fmax2 is a frequency obtained from the intersection of the operable range Ip2 with two pumps considering the limit load current value and the piping resistance curve Lr as described above.

  The amount of water-total head characteristic when operating at this frequency Fmax2 is Cmax2 '. The amount of water at the intersection of the curve Cmax2 'and the curve Lr is Q01i, and the total head is H01i. From the figure, it can be read that Q01i ≧ Q02 and H01i ≧ H02. In other words, by setting the frequency upper limit of the two pumps to Fmax2 as in this embodiment, it is possible to supply water with a larger amount of water and higher water supply pressure even in the operation of the same two pumps. It becomes.

  Further, in this embodiment, similarly to the case of three or four pumps, the frequency upper limit values Fmax3 and Fmax4 are determined in consideration of the limit current values corresponding to the respective numbers. Note that Fmax3, Fmax3 ≧ Fmax2, and Fmax4 satisfy Fmax4 ≧ Fmax3. Next, the case of performing the control of the plurality of pumps will be described.

First, pressure control in the case where the frequency upper limit value is not changed according to the number of water supply apparatuses having a plurality of pumps will be described.
FIG. 5 shows an operation characteristic diagram of a water supply apparatus having a plurality of pumps at this time. A curve Cmax1 shows a used water amount-feed water pressure characteristic curve when one pump is operated at the frequency upper limit value Fmax1 in the control considering the pump limit load current value. A curve Cmin1 shows a water consumption-feed water pressure characteristic curve when one pump is operated at a frequency Fmin1.

  Curve Cmax2 shows two pumps, curve Cmax3 shows three pumps, and curve Cmax4 shows a water usage-feed pressure characteristic curve when all four pumps are operated in parallel at the same frequency upper limit value Fmax1. . In addition, Cmin2 is a water consumption-feeding pressure characteristic curve when one unit is operated in parallel at Fmax1 and the other unit is Fmin2, Cmin3 is a water consumption amount-water supply when two units are operated in parallel at Fmax1 and the other unit is operated at Fmin3. A pressure characteristic curve, Cmin4, is a used water amount-water supply pressure characteristic curve when three units are operated in parallel at Fmax1 and the other unit at Fmin4.

  A curve Lr indicates a piping resistance curve such as valves and piping generated when pumping water as in FIG. 2. For example, H00 is a target pressure at a point where the amount of water is zero. That is, in the case of the estimated terminal pressure constant control, the control is performed so that the operating point is on the curve Lr. For example, H01 is a target pressure when operating one pump at the frequency Fmax1. At the same time, H01 is also a target pressure during parallel operation of one pump frequency Fmax1 operation and another one frequency Fmin2 operation, and is indicated by an intersection of the curve Cmax1, the curve Cmin2, and the curve Lr. The amount of water at this time is Q01.

  H04 is a target pressure when four pumps are operated in parallel at the frequency Fmax1, and the amount of water at this time is Q04. Similarly, H02 is a target pressure when two pumps and H03 are operated in parallel at a frequency Fmax1. Thus, these target pressures are on the curve Lr.

  H01on indicates the starting pressure when the second unit is additionally started, and H02on and H03on indicate the starting pressure when the third unit and the fourth unit respectively follow-up. H03off is the stop pressure for stopping one of the four units. H02off is the stop pressure for stopping one of the three units. H01off is for stopping one of the two units. Stop pressure. In this way, control is performed while increasing or decreasing the number of operating pumps as necessary so that the water supply pressure and the amount of water are on the pipe resistance curve Lr.

  FIG. 6 is a diagram for explaining operating characteristics when a frequency upper limit value is changed in accordance with the number of pumps operating, which is a feature of the present embodiment, in a water supply system having a plurality of pumps. The same symbols as in FIG. 5 are used in the same meaning as in FIG. In FIG. 5, as the upper limit value when operating two pumps, the amount of water used—water supply in which each pump is moved at the frequency Fmax1, that is, the frequency upper limit value in consideration of the limit load current value of one pump. The pressure characteristic curve was indicated by Cmax2. Similarly, when three or four pumps are operated, the frequency upper limit value is Fmax1, and the respective water consumption-feed water pressure characteristic curves are indicated by Cmax3 and Cmax4.

  However, when the number of pumps increases as described above, the frequency upper limit value is not Fmax1, and it is shown in FIG. In FIG. 6, the frequency upper limit value in the control in which the two pumps consider the pump limit load current value is indicated by Fmax2, and the used water amount-feed water pressure characteristic curve at this time is indicated by Cmax2 '. As described above, it can be seen that Cmax2 'enables a larger amount of water and a higher water supply pressure than Cmax2. In other words, when the frequency upper limit value is Cmax2, the third unit must be operated in the water volume (Q02 to Q01i), but by increasing the frequency upper limit value to Cmax2 ′, water can be supplied to the water volume Q01i with two units. Can be performed.

  Further, a curve Cmin3 'shows a used water amount-feed water pressure characteristic curve when one pump is operated in parallel at Fmax2 and the other pump at Fmin3'. Thus, when starting the operation of the third pump, it is operated at the minimum frequency Fmin3 ′. For example, when the pump drive source is an induction motor, the power loss is larger as the rotation speed is lower. . That is, if water can be supplied by operating two pumps without moving the third pump, an efficient water supply device can be provided.

  Similarly, curves Cmax3 ′ and Cmax4 ′ are the upper limit frequency value Fmax3 or Fmax4 in the control in consideration of the pump limit load current value in three or four pumps, and the used water amount-feed water pressure characteristic curve when the pump is operated. Is shown. Curve Cmin3 ′ shows a water consumption-water supply pressure characteristic curve when two pumps are operated in parallel at Fmax3 and the other one at Fmin3 ′. Curve Cmin4 ′ shows three pumps at Fmax4 and the other at Fmax3 ′. The water consumption amount-feed water pressure characteristic curve when operating in parallel at Fmin4 ′ is shown.

  For example, H01i is a target pressure when two pumps are operated at a frequency Fmax2. At the same time, it is also a target pressure during parallel operation in which two pumps are operated at a frequency Fmax2 and another pump is operated at a frequency Fmin3 '. This target pressure is indicated by the intersection of the curve Cmax2 ', the curve Cmin2', and the curve Lr. The amount of water at this time is Q01i.

  Similarly, H02i is a target pressure when three pumps are operated in parallel at a frequency Fmax3, and the amount of water at this time is Q02i. H03i is a target pressure when four pumps are operated in parallel at a frequency Fmax4. The amount of water at this time is indicated by Q03i. Thus, in the estimated terminal pressure constant control, the target pressure is on the curve Lr, and the frequency and number of pumps are controlled so that the target pressure moves on the curve Lr according to the amount of water used.

  As the timing at which the number of pumps changes, H01ion indicates the starting pressure when the third unit additionally starts, and H02ion indicates the starting pressure when the fourth pump starts following. H02ioff is a stop pressure for stopping one of the four units, and H01ioff is a stop pressure for stopping one of the three units.

  From FIG. 6, Q01i ≧ Q02, Q02i ≧ Q03, Q03i ≧ Q04, H01i ≧ H02, H02i ≧ H03, H03i ≧ H04, and by changing the frequency upper limit value according to the number of operating units, a wide range of water supply with a small number of pumps Can be made possible.

  For example, in the range of water quantity Q02 to Q01i, when the frequency upper limit value is Fmax1, water cannot be supplied unless three pumps are operated, but in this embodiment, water can be supplied with two pumps. It becomes possible. Since the efficiency of the motor generally improves when the number of rotations is high, the energy saving effect can be achieved if water can be supplied by two pumps to the water supplied by three pumps. Similarly, in the range of Q03 to Q02i and the range of Q04 to Q03i, an energy saving effect can be obtained according to the present embodiment.

Next, a specific control flow will be described with reference to the drawings.
FIG. 7 shows a data table having parameters relating to pressure control. These pressure control parameters are stored in the memory of each control board and interface board. Although description is omitted, parameter setting can be set by setting means such as a display unit and an operation unit provided in these control boards or interface boards. These data may be stored in each control board and interface board on which the microprocessor is mounted, or may be stored in any one place.

FIG. 8 shows a communication data format when a communication signal is transmitted from the interface board to each control board. Further, the interface board and each control board are identified by the ID number. For example:
Board name ID number
Interface board: 0
Control board 1st unit: 1
2nd control board: 2
Control board 3rd: 3
Control board 4th: 4
FIG. 9 shows the command of the transmission format of the communication signal and the contents of the data. When the command number is 0, the content is an operation command. When it is 1, it means parameter setting, and when it is 2, it means a data transmission request, and a command command is given in combination with data. For example, if the transmission format ID number is 1, the command number is 0, and the data is 3, the first control board (pump 8-1, motor 9-1, inverter 1-2, control board 1- 1) is recognized as a preceding operation command from the interface board I / O.

  FIG. 10 shows a communication data format when a signal is returned from each control board to the interface board. When communication is normally received from the interface board to the control board, data including an error is received. FIG. 11 shows the command number and the content of data for the command.

  FIG. 12 is a flowchart showing the control procedure of the interface board, which is mounted on the microprocessor MCU as a program. This control flow will be described in detail later along with the control flow of the control board.

  FIG. 13 is a flowchart showing the control procedure of each control board, and the same program is mounted on each microprocessor MCU1-2 to MCU4-2 as a program. The n-type water supply control system referred to here is an n-type system consisting of a pump, a motor, valves, an inverter body, and a control board as a set, and the inverter body and control board are identical to each other. The software is installed and the same function is added. However, the pressure sensor and the interface board are common to the n-fold system. 12 and 13 both include communication processing between the interface board and each control board and pressure detection signal acquisition processing in the repeated processing, but are distinguished from these repeated processing. For example, communication is performed by interrupt processing. Control and pressure detection signal acquisition processing may be performed.

  FIG. 14 is a flowchart showing the procedure of step 202 (operation number confirmation process) in FIG. Data related to the number of pumps is read from the memory MO (step 300 in FIG. 14), and variables necessary for processing are initialized (steps 301 and 302). Confirm the reception command from No.1 to No.m in the repeated processing of 303 to 306 (confirm the contents of memory M107 to M112 in FIG. 7) The number of control boards that are present is checked, and the number is set as the number of operating boards (step 307 in FIG. 14).

  When the operation mode selection switch MODSW in FIG. 1 is turned off, all the pumps are always in a stopped state, and when in the manual mode, the pumps are operated and stopped by manual operation from the operation unit of each control board. When pressure control is performed and it is automatic, the parameters for pressure control, number control, start and stop stored in the storage unit of the interface board are compared with the water supply pressure signal detected by the pressure sensor, Start, stop and control the pressure of the pump.

  Regardless of the operation mode, the interface board always performs a command transmission process to the control board, a signal reception process from the control board, and a pressure detection signal acquisition process of the pressure sensor (steps 100 to 102 in FIG. 12). ). Now, it is assumed that the operation mode selection switch MODSW is automatic and the feed water pressure is less than Hon of the pump start pressure with all the pumps stopped. The interface board executes steps 103 to 105 in FIG. 12, and sets the number of operating units to one. After steps 107 and 108, the process returns to the beginning. Next, when 100 steps are executed, the command transmission of the preceding operation (ID number of transmission format is 1, command number is 0, data is 3) is executed to the control board as the preceding machine, for example, control board No. 1 To do. In step 101, a reception signal is received from the control board for the command transmission of the preceding operation.

  On the other hand, the control board performs reception processing from the interface board or another control board in 200 steps. The reason why the communication is received not only from the interface board but also from other control boards is because the communication signal lines (S5 to S8, S9) are common. In the case of an operation command from the interface board to one of the control boards, the contents of the command are stored in the corresponding memory area of M107 to M112 in FIG. 7 (for example, a standby “2” command to the first machine). For example, “2” is stored in C1 of M107).

  In the case of a response to a data transmission request from another control board to the interface board, the operation frequency is stored in the corresponding area of M113 to M118 in FIG. 7 (for example, the first machine returned the operation frequency “60” Hz). If “”, “60” is stored in F1 of M13). When a command for itself is received from the interface board, in step 201 in FIG. 13, a signal is returned to the interface board in response to the received command, and the received content is from the interface board to another control board. If it is, or if it is a reply from another control board, the reply is not made and the process is terminated.

  Next, after confirming the number of operating units, a process for acquiring a pressure detection signal of the pressure sensor is performed (steps 202 and 203 in FIG. 13). Further, step 204 in FIG. 13 is executed, the control state of the inverter body is confirmed, and the current operating frequency is acquired and stored. When a command for preceding operation is received from the interface board, steps 205, 209, 214 and 218 in FIG. 13 are executed.

  If the pump is operating in step 218, the pressure control, number control, start / stop parameters stored in the storage unit are compared with the feed water pressure signal detected by the pressure sensor, and pressure control is performed. The optimal frequency is commanded to the inverter body (steps 219, 221, 222). On the other hand, if the pump is stopped in step 218, the inverter body is started and the operation frequency is commanded (steps 219, 220, and 222). As described above, the preceding machine performs a speed change operation that changes the frequency according to the feed water pressure. Since it is a preceding aircraft, the amount of water at this time increases from 0 to Q01 in FIG.

When the amount of water used further increases and reaches Q01 shown in FIG. 6, the inverter operating frequency becomes Fmax1 by the pressure control in step 221 in FIG. 13, and the water supply pressure reaches the target value H01 in Q01. Therefore, it is on Cmax1 of the used water amount-feed water pressure characteristic curve of the pump. Further, when the amount of water used increases, the water supply pressure decreases and reaches the second follower pump start pressure H01on. A control flow of the interface board at this time will be described with reference to FIG.
The interface board executes the processing of steps 100 to 104 and 106 in FIG. 12, and confirms whether the operation frequency of the preceding machine pump operating in step 107 is Fmax1. In this case, after checking whether the state of the operation frequency Fmax1 has passed t1 seconds in 110 steps, the water supply pressure (pressure data NDP detected by the pressure sensor) at that time is lower than the second follower pump start pressure H01on. If so, the number of operating units is two (111 steps). Steps 113 and 114 are returned to the beginning of the process.

  Next, when executing 100 steps, a command transmission of the follow-up operation is transmitted to the control board as the follower, for example, the second control board (the ID number of the transmission format is 1, the command number is 0, and the data is 4). Run. In step 101, a reception signal is received from the control board for the command transmission of the follow-up operation.

  After executing steps 200 to 204 in FIG. 13, the control board executes steps 205, 209, 214, 218, and 223 when it receives a follow-up operation command from the interface board, and performs processing if it is already in operation. If it is stopped, the inverter main body is activated (step 224). In step 225, it is determined whether the command frequency is appropriate for the current number of units operated (number confirmed in step 202). If not, the command frequency is updated (step 226). As described above, the follower performs a constant speed operation that operates at a certain frequency, which is determined according to the number of operating units.

  This constant frequency means that the frequency and the number of pumps are controlled so that the operating point is on the piping resistance curve as shown in FIG. For example, when the amount of water used Q01i is exceeded, Unit 3 starts a follow-up operation and becomes parallel operation of three units. When the amount of water used Q02i is exceeded, Unit 4 starts a follow-up operation and becomes parallel operation of four units. Here, as described above, the unit that performs the follow-up operation determines whether the command frequency is appropriate for the current operation number (the number confirmed in step 202) in step 225 in FIG. The command frequency is updated (step 226).

  Next, a case will be described in which the amount of water used decreases from Q01i to less than Q01 in the state in which Unit 1 is in the preceding operation and Unit 2 is in the following operation. In FIG. 6, the water supply pressure is H01 at the usage water amount Q01, and the No. 1 unit operates at a constant speed at the frequency Fmin2 and the No. 2 unit is at the frequency Fmax1, and thus is on Cmax1 of the usage water amount-feed water pressure characteristic curve of the pump. When the amount of water used is further reduced, the water supply pressure exceeds the one-unit stop pressure H01off when two units are operating. The interface board executes the processing of steps 100 to 104, 106, 112, and 113 in FIG. 12, confirms whether the operation frequency of the preceding machine pump that is operating in step 114 is Fmin2, and in step 115, the operation frequency Fmin2 is set. It is confirmed whether t2 seconds have elapsed, and when the water supply pressure (pressure data NDP detected by the pressure sensor) is equal to or higher than the stop pressure H01off when two units are operating, the number of units operated is set to one (116 Step), return to the beginning of the process.

  Next, when executing 100 steps, a standby command transmission (transmission format ID number 1, command number 0, data 2) is performed to the first control board, which was the preceding machine, and follows. The command transmission of the preceding operation (ID number of the transmission format is 1, the command number is 0, and the data is 3) is executed with respect to the second machine of the control board that was the machine. In step 101, reception signals are received from the control boards for these command transmissions.

  The first machine stops in the order of steps 200 to 205, 209, and 214 to 217 in FIG. 13 and enters a standby state. Unit 2 switches from constant speed operation as a follower to shift operation as a preceding machine in order of 200 to 205, 209, 214, 218, 219, 221, 222.

  In this embodiment, in FIG. 6, when the amount of water used decreases from Q03i to less than Q01 after the parallel operation of the four units, the speed change operation pump of the first unit in the preceding operation stops and the second unit operates at a constant speed. From driving to shifting operation as the preceding machine, Unit 3 and 4 continue to operate at constant speed, then Unit 2 stops, Unit 3 shifts to operation, and Unit 4 continues to operate at constant speed. Furthermore, No. 3 stops and No. 4 shifts. The operating frequency of the pumps that continue constant speed operation varies according to the number of operating units.

The 2nd Example of the water supply apparatus by this invention is described using drawing.
This embodiment is characterized in that the number of operating units is confirmed by the content of the preceding driving command. FIG. 15 shows the command of the transmission format of the communication signal and the contents of the data in this embodiment. The command for the preceding operation is "3" for one operating unit (independent operation), "5" for two operating units (when two units are in parallel), and "9" for six operating units (when six units are in parallel). Distinguish. For example, when the ID number of the transmission format is 1, the command number is 0, and the data is 6, it is the preceding machine speed change operation at the time of three units parallel operation.

  The control board confirms the number of operating units in step 202 shown in FIG. Data related to the number of pumps is read from the memory MO (step 400 in FIG. 16), and variables necessary for processing are initialized (steps 401 and 402). The number of the machine No. 1 that has received the preceding operation command is confirmed (the contents of the memories M107 to M112 in FIG. 7 are confirmed) from the No. 1 machine by repeating the steps 403 to 406, and the machine number x is not 0 (some If that machine has received a preceding operation command), the command content of the No. x machine that has received the preceding operation command is confirmed, and the number of operating units is judged from the command content (steps 407, 409, 410 in FIG. 16 or 407) 409, 411 steps). When the unit number is 0, the number of operating units is 0 (steps 407 and 408 in FIG. 16).

The 3rd Example of the water supply apparatus by this invention is described using drawing.
In the present embodiment, the command frequency of the control board that performs the follow-up operation is changed according to not only the number of operating units but also the operating frequency of the preceding machine (shift operation). FIG. 17 is a flowchart of the control procedure in this embodiment. The control board adds 230 steps (follow-up frequency update process) to the process during follow-up operation.

  The detailed procedure of the tracking frequency update process will be described with reference to FIG. In step 500, data relating to the number of pumps is read from the memory MO, and variables necessary for processing are initialized (steps 501 and 502). The number of the machine No. 1 that has received the preceding operation command is confirmed from the No. 1 units by repeating the steps 503 to 506 (the contents of the memories M107 to M112 in FIG. 7 are confirmed), and the No. x machine that has received the preceding operation instruction (If the address corresponding to the preceding machine is confirmed in the memories M113 to M118 in FIG. 7), and if the operating frequency of the x machine is larger than the command frequency for its own inverter, the operating frequency of the x machine is The command frequency is set (steps 507 and 508).

The system block diagram which showed the structure of the water supply system of this invention. Explanatory drawing of the amount of water used-pump water pressure characteristics of a pump, and the pump operable range by load limitation. The operation characteristic figure of one pump in presumed terminal pressure constant control. The operation characteristic figure of two pumps in presumed terminal pressure constant control. Operation characteristic diagram of a water supply system having a plurality of pumps. The operation characteristic figure of the water supply system which has a plurality of pumps by the present invention. Data table with parameters related to pressure control. Communication data format transmitted from the interface board to the control board. Send data command and data contents list for the command. Communication data format for returning from the control board to the interface board. Reply data command and data contents list for the command. The control flowchart of an interface board | substrate. The control flowchart of a control board. The flowchart of a driving number determination process. The communication data format transmitted from the interface board to the control board in the second embodiment. The flowchart of the operation number determination process in a 2nd embodiment. The control flowchart of the control board in a 3rd embodiment. The command frequency update processing format in the third embodiment. The operation characteristic figure in the conventional pump one unit operation. The operation characteristic figure of one pump in the conventional estimation terminal pressure constant control. The operation characteristic figure of two pumps in the conventional estimated terminal pressure constant control.

1-1, 2-1, 3-1, 4-1 control board, 1-2, 2-2, 3-2, 4-2 inverter body, 8 pump, 9 motor, 11 suction pipe, 12 check valve , 13, 14 Gate valve, 15 Water supply pipe, 16 Sensor, 17 Pressure tank, I / O interface board.

Claims (10)

A plurality of pumps driven to rotate by an electric motor;
Variable speed means for driving the electric motor to a variable speed,
In the water supply apparatus in which pressure control is performed by rotationally driving the pump to a variable speed by the variable speed means,
An upper limit value is set in advance for the current flowing to the motor, and an upper limit value of the pump frequency is set based on the upper limit value of the current and the piping resistance curve, and the upper limit value of the frequency is large in the number of operating pumps. The water supply apparatus characterized by being set so large . In claim 1, the amount of water each frequency of the upper limit and the pump current - water pressure curve and quantity - operating range of the pump and a load current curve is determined in advance, the pressure control Ru performed within the operating range A water supply device characterized by that. 3. The water supply apparatus according to claim 2 , wherein a target pressure corresponding to the amount of water used is preset, and an upper limit value of the pump frequency is preset based on the target pressure and the operable range. In Claim 3, the said target pressure is preset by the piping resistance curve, and the estimated terminal pressure constant control is performed by controlling the frequency of the said pump so that there exists an operating point on this piping resistance curve. A water supply device. In claim 2, the amount of water by the operation number of the pump - operating range of the pump by the water supply pressure characteristics change is river water and wherein the Rukoto. In the water supply method of performing pressure control by rotationally driving the pump to a variable speed,
An upper limit value is set in advance for the current flowing to the pump, and an upper limit value of the pump frequency is set based on the upper limit value of the current and the piping resistance curve, and the upper limit value of the frequency is large in the number of operating pumps. The water supply method characterized by being set so large as it is. 7. The operation range of the pump is determined in advance from the upper limit value of the current, a water amount-feed water pressure curve and a water amount-load current curve for each pump frequency, and pressure control is performed within the operation range. Water supply method characterized by. 8. The water supply method according to claim 7, wherein a target pressure corresponding to the amount of water used is preset, and an upper limit value of the pump frequency is preset based on the target pressure and the operable range. In Claim 8, the said target pressure is preset by a piping resistance curve, and the estimated terminal pressure constant control is performed by controlling the frequency of the said pump so that an operating point exists on this piping resistance curve. Water supply method. 8. The water supply method according to claim 7, wherein the operable range of the pump is changed by changing the water amount-water supply pressure characteristic depending on the number of the pumps operated.

Images