JP4364014B2 - Pump operation control device - Google Patents

Description

  The present invention relates to a pump operation control device that receives power supplied from an AC power supply system and intermittently operates the pump by on / off control, and is particularly suitable for use when the pump is used in a cold region. It relates to the device.

  Conventionally, when a water supply apparatus is used in a cold region, prevention of freezing of a pump has always been a problem. The most common method for preventing freezing of this pump is to attach a resistance heating element such as cement resistance to the pump, detect the outside air temperature with a temperature sensor, and when the outside air temperature falls below a certain temperature, the heating element A current is supplied to the pump, and the pump is heated to prevent freezing. However, this method requires that a resistance heating element be attached to the pump, which increases the cost and heats the entire pump, which is not preferable from the viewpoint of energy saving.

  Various methods for preventing the pump from freezing without using a resistance heating element have been studied. For example, in a water supply apparatus that uses an inverter to operate a pump at a variable speed, the pump is forced to operate at a frequency lower than the normal operation frequency when it is determined that the temperature is low enough to freeze the pump. There has been proposed a method for preventing freezing (see Patent Document 1). However, in this method, since it is operated at a frequency lower than the normal operating frequency, there is also an influence of noise caused by operating the pump. Especially in small-scale household water supply devices, it is installed near a residence. In many cases, there was a problem especially in the generation of late-night noise. Further, as long as the pump is operated even at low speed, energy is consumed to some extent, and there is a problem in terms of energy saving.

Further, as a water supply device with a freeze prevention device, there has been proposed a water supply device that causes the pump to be shut off when the outside air temperature or the water temperature of the pump falls below a certain temperature (see Patent Document 2). In this water supply apparatus, when the temperature of the pump becomes low when the pump is likely to freeze, the pump is shut off to generate heat and prevent the pump from freezing. However, even in this water supply device, especially in the case of a small-scale water supply device, there are many cases where the water supply device is located near a residence, etc. Since it is operated, energy loss is large, which is not preferable from the viewpoint of energy saving.
JP-A-10-169568 JP-A-4-203392

  The present invention has been made in view of the above-described circumstances, and prevents the water supply apparatus from freezing without using an external heating element such as a heater, without generating noise, and without consuming excessive energy. An object of the present invention is to provide an operation control device for a pump that can be used. In particular, an object of the present invention is to provide a pump operation control device suitable for a small-scale water supply device that simply controls the pump on and off.

A pump operation control device according to the present invention includes a temperature sensor that detects an outside air temperature or the temperature of the pump in a water supply device that controls on / off operation of a pump integrated with the motor driven by a motor, and the motor includes Supplying the current based on a plurality of firing periods corresponding to the output of the temperature sensor , supplying a current that does not rotate or slightly rotates, and that the motor generates sufficient heat. The pump is configured to prevent the pump from freezing by controlling on / off , and the plurality of firing periods are based on the wave number of the voltage waveform .

  According to the present invention, in a pump of a water supply apparatus that is operated by intermittently supplying current from an AC power source by on / off control, the motor does not rotate or slightly rotates with respect to the motor, and the motor is sufficient. An electric current that generates heat is supplied to the pump to prevent the pump from freezing. That is, the motor stator and the rotor are used as a heating element by supplying a current that does not satisfy the starting torque to the extent that the motor does not rotate or slightly rotates, and the heating element such as an external heater is used. Without using the pump, it is possible to prevent the pump from freezing. Since the current is less than the starting torque, the motor and the pump hardly rotate and noise can be prevented. Further, since heating is performed from the inside of the motor pump, energy consumption for preventing the pump from freezing can be minimized.

Here, it is preferable that the on / off operation control of the pump uses a non-contact switch made of a semiconductor element. Thereby, the long life and high reliability as a small-scale water supply apparatus are realizable. In addition, the current control is preferably performed by on / off control of the semiconductor element in units of wave numbers by zero-cross control, and the current control may be performed by controlling the phase angle of the semiconductor element in the on state. Moreover, water supply apparatus includes the operation control device, it is preferable to control the pump based on the discharge pressure of the pump detected by the pressure sensor.

  In general, according to the present invention, there is provided an operation control device for a pump suitable for a small-scale water supply device that does not use an external member such as a resistance heating element, generates no noise, and minimizes energy consumption. Provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the member or element which has the same effect | action or function, and the overlapping description is abbreviate | omitted.

  FIG. 1 shows a configuration example of a water supply apparatus according to an embodiment of the present invention. This water supply apparatus is suitable as a small-scale water supply apparatus for a small-scale housing complex, or a small-scale water supply apparatus such as a household water supply apparatus that draws and uses well water. In this water supply apparatus, the water supply is performed by a motor pump 13 including a pump 13b integrated with a motor 13a. The motor pump 13 is supplied with electric power from a commercial AC power supply system and is controlled to be turned on and off by a non-contact switch 21. The And in this water supply apparatus, long life and high reliability of a water supply apparatus are realizable by adopting non-contact switches, such as a triac, on / off control of the alternating current power supply supplied to the motor pump 13. FIG. In addition, the adoption of a non-contact switch using a semiconductor element eliminates the switch-on sound at the time of on / off and can provide a water supply device with extremely low noise.

  In the motor pump 13, a motor 13a and a pump 13b are integrally housed in the same casing, the motor 13a is constituted by an induction motor or the like, and the pump 13b is constituted by a vortex pump or the like. The motor pump 13 has, for example, a single-phase 100V, about 100 to 400 W, or a three-phase 200 V, about 250 to 750 W rating.

  In this water supply apparatus, for example, the water receiving tank 11 is provided with a pipe 12 for supplying water to the customer side, and a motor pump 13 is disposed in the middle of the pipe 12 to pressurize the water stored in the water receiving tank 11 and demand. Supply to the house side. A pressure tank 14 is disposed on the discharge side of the pump 13 b, and the pump discharge side pressure is detected by the pressure sensor 15. Further, a flow rate sensor 16 for detecting a small flow rate or the like is disposed on the route to the water supply destination of the pipe 12, and these signals are input to a control device 20 constituted by a microcomputer or the like in the control panel 17.

  AC power is supplied to the motor pump 13 from a commercial AC power source via a contactless switch 21 such as a triac in the control panel 17 to rotate the pump 13b. The contactless switch 21 such as a triac receives a signal from the control device 20 and intermittently supplies current to the motor from the AC power supply system by on / off control. The pump operation control device has the control device 20 including the microcomputer as described above, and the signal of the pressure sensor 15 and the signal of the flow sensor 16 are controlled via the input connectors. Input to the device 20. Moreover, the temperature sensor 18 which detects external temperature is provided, and the signal of the detected temperature is taken in into the control apparatus 20 from an input connector.

  Similarly, the water receiving tank 11 is provided with a float switch 19, and the water level of the water receiving tank is detected by the float switch 19 and taken into the control device 20. Therefore, in this pump operation control device, when the pump discharge side pressure detected by the pressure switch 15 rises due to the operation of the pump and reaches a certain value, a signal is sent to the contactless switch 21 from the AC power supply system. Is turned off (blocked), and the operation of the motor pump 13 is stopped. When the operation of the pump is stopped, the pressure inside the pressure tank 14 gradually decreases. When the pressure drops to a predetermined lower limit value, a signal is sent to the non-contact switch 21 to turn it on (conductive state) and to the motor pump 13. Supply power and resume operation. Therefore, in the motor pump 13, the supply of AC power is on / off controlled and the operation of the motor pump 13 is on / off controlled so that the pressure detected by the pressure sensor 15 is within the range between the upper limit value and the lower limit value.

In addition, when the water level detected by the float switch 19 in the water receiving tank 11 becomes, for example, a reduced level below a certain value, the operation of the motor pump 13 is forcibly stopped and the motor pump 13 is prevented from being in a drought operation state. is doing.
When the pump discharge side pressure reaches a certain value, the operation of the motor pump 13 is not stopped, but it is detected by using the flow sensor 16 that the flow rate is below a certain flow rate during the pump operation. The operation may be stopped. In this case as well, the operation of the motor pump 13 is resumed when the pressure inside the pressure tank 14 drops to a predetermined lower limit value.

  The temperature sensor 18 is a temperature sensor for detecting the outside air temperature. When the detected outside air temperature becomes 5 ° C. or less, for example, the pump may freeze, so that a constant current less than the starting torque is supplied to the motor. Yes. That is, the output of the temperature sensor 18 is taken into the control device 20, and when a predetermined outside air temperature or less is detected inside the control device 20, the non-contact switch 21 is controlled to be below the starting current and the motor stator. The motor 13a is supplied with a current having a constant current value such that the motor rotor generates heat. The current causes the motor stator and the motor rotor to generate heat without rotating the pump, thereby raising the water temperature inside the pump and preventing the pump from freezing.

  When the outside air temperature rises, for example, 10 ° C. or higher, the control device 20 detects this, turns off the non-contact switch 21 and stops the supply of a constant current value to the motor 13a. Thus, it is preferable that the current supply with a constant current value for preventing freezing of the motor pump 13 has a hysteresis characteristic so that it is turned on at, for example, 5 ° C. or less and turned off at 10 ° C. or more. As a result, chattering during on / off control of a current having a constant current value for preventing freezing can be prevented.

  Fig.2 (a) shows the structural example of the operation control apparatus of the pump of the 1st Embodiment of this invention. In this embodiment, a single-phase motor pump is used and is connected to a single-phase 100V commercial AC power supply. As described above, an induction motor is used for the motor 13a, and a vortex pump is used for the pump 13b. A contactless switch 21 and a current sensor 22 such as a CT are arranged in the R phase of the single-phase power source. The RS phase voltage between R and S is detected by the zero cross detection circuit 23. This detection output is taken into a CPU device 27 such as a microcomputer, and based on the data stored in the storage device 28, the non-contact switch 21 is ignited by the R-phase ignition circuit 24 so that a constant average current flows. Timing controlled. Further, the R-phase current is detected by the current sensor 22 and taken into the CPU device 27 through the detection circuit 25.

  The control device 20 includes a storage device 28 connected to the CPU device 27. The storage device 28 is provided with a table of constant current values for preventing freezing corresponding to the installation environment of the motor pump 13. In this table, for example, preferable constant current values corresponding to a plurality of outside air temperature levels such as an outside air temperature of 5 ° C. or less, 0 ° C. or less, −5 ° C. or less, −10 ° C. or less can be stored.

  Further, as another table of the storage device 28, data for timing control of ignition of the contactless switch 21 for supplying a constant current value is stored. The above-described on / off control during pump operation turns on or off the non-contact switch 21 based on the pump discharge side pressure or the like. In the on state, the rated current flows, the pump is operated at the rated speed, and the off state. No current flows and the pump stops.

  However, the constant current supplied to prevent the pump from freezing has to be a current that is sufficient for the motor to generate sufficient heat and that is equal to or less than the starting torque. For this reason, the non-contact switch (triac) 21 is subjected to on / off control or phase angle control in units of wave numbers, thereby forming a constant current value for preventing the above-described pump freeze.

  Therefore, when the outside air temperature decreases to, for example, 5 ° C. or less and the constant current is supplied for the freeze prevention control of the motor pump of the present invention, for example, as shown in FIGS. The non-contact switch 21 is controlled to be ignited in units of one-cycle waveform by a zero cross control method for detecting a point where the voltage waveform crosses zero. FIG. 4 (a) is one that is fired at a rate of one cycle in five cycles, (b) is one that is fired at a rate of one cycle in four cycles, and (c) is three cycles. (D) is such that it is fired at a rate of one cycle every two cycles. In addition, (e) is such that half-waves are alternately fired on the + side − side at a rate of 0.5 periods in 1.5 periods, and (f) is 0.5 periods in 3.5 periods. The half wave is alternately ignited on the + side and the − side at the rate of. That is, the zero-cross of the RS voltage is detected by the zero-cross detection circuit 23, and the R-phase ignition circuit 24 is instructed by the instruction of the CPU device 27 based on the wave-number-unit ignition cycle data previously stored in the table of the storage device 28. Sends an on / off control signal to the non-contact switch 21. As a result, it is possible to continue to supply a constant average current (effective current value) at which the motor rotor does not rotate or slightly rotates below the starting current and the motor sufficiently generates heat.

  Note that a preferable value of the average current (effective current value), that is, the firing period of the zero cross control is stored in the control device 20 as a table corresponding to the outside air temperature, for example, and an appropriate average current (corresponding to the outside air temperature ( The firing cycle is controlled so that the current effective value is obtained. The current flowing in the single-phase circuit may be detected by the R-phase current detection circuit 25 and fed back to the R-phase ignition circuit 24 in the CPU device 27, and the ignition cycle may be automatically controlled by PID control or the like.

  In addition, the ignition control is not limited to zero-crossing control, and it is of course possible to employ a phase control method for igniting a part of a half-cycle waveform as shown in FIG. In the example shown in FIG. 5, the firing angle in the half cycle is wide on the left side in the figure, and the firing angle is gradually narrowed toward the right side. Along with this, the average current (current effective value) decreases sequentially from the left side to the right side. Here, an example using a triac as the contactless switch 21 has been described, but a semiconductor element such as an IGBT or a power MOSFET may be used.

  FIG. 3 shows a configuration example of a pump operation control apparatus according to the second embodiment of the present invention. In this embodiment, the case where the three-phase motor pump 33 is connected to a three-phase 200V commercial AC power supply is shown. The three-phase motor pump 33 is also configured by integrally forming a three-phase induction motor 33a and a vortex pump 33b, and a motor pump having a rating of about 200V and 250-750W, for example, is used. In this embodiment, a three-phase motor pump 33 is connected to a commercial AC three-phase power source. For this reason, the non-contact switches 31 and 32 are connected to the R phase and the T phase, respectively. The RS phase voltage is detected by the zero cross detection circuit 35, and the ST phase voltage is similarly detected by the zero cross detection circuit 36. The non-contact switch 31 connected to the R phase is controlled by the R-phase ignition circuit 37, and the non-contact switch 32 connected to the T-phase is also controlled by the T-phase ignition circuit 38. . The R-phase current is detected by the R-phase current detection circuit 39, and similarly, the T-phase current is detected by the T-phase current detection circuit 40.

  When performing supply control of a constant current for preventing freezing, the non-contact switches 31, 32 such as triacs are not rotated by the motor 33a by the zero cross control or phase control similar to the above, or Supply a current that is less than the starting current so that it rotates slightly. By supplying this current, the motor stator and the motor rotor generate heat, the water temperature of the integrally configured pump unit rises, and this prevents the pump from freezing, as in the above embodiment.

  This constant current value control for preventing freezing can be controlled by any of the above-described zero cross control method and phase control method. In this way, when the outside air temperature is lowered, the current is supplied to the stator windings and the motor rotor of the motor without rotating the pump by continuously supplying an average current that is less than the starting torque to the pump. The motor 33a rises in temperature due to the heat generated by the resistance loss accompanying this current, and the pump 33b configured integrally therewith is also heated to prevent freezing. Therefore, the problem of noise caused by the rotation of the motor pump does not occur at all, and the motor pump generates heat from the inside, so that the pump portion can be efficiently heated and the pump is prevented from freezing with a minimum amount of energy consumption. be able to.

  Note that the magnitude of the constant current value for preventing freezing depends greatly on the outside air temperature. The storage device 28 is preferably provided with a table of preferable constant current values corresponding to the outside air temperature. As a result, the amount of constant current supplied to the motor is changed in response to changes in the outside air temperature, in other words, changes in the cooling state, and even in the case of extreme cooling, the energy consumption of the pump is reduced. Freezing can be prevented.

Instead of the outside air temperature, a temperature sensor is attached to the pump casing or the pump piping, or another temperature sensor is attached together with the outside air temperature sensor, and the temperature of the piping near the pump casing or the pump You may control by the various control methods mentioned above so that it may become the fixed temperature which can prevent freezing. That is, by detecting the temperature from a temperature sensor attached to the pump casing or piping, and performing zero-cross control or phase angle control of the contactless switches 31 and 32 in units of wave numbers so that the temperature is constant, feedback is achieved. Control is possible. This also makes it possible to supply a current having the above-mentioned constant current value that is preferable for preventing the pump from freezing in response to fluctuations in the outside air temperature.
In many cases, an external capacitor such as a starting capacitor or a phase advance capacitor is used for the induction motor. When the motor does not rotate or is supplied with a current equal to or less than the starting current that is slightly rotated, not only the motor stator and the motor rotor but also these capacitors generate heat. Therefore, the water supply device can be more effectively prevented from freezing by disposing these capacitors in the vicinity of places where the water supply device is easily frozen, such as pumps and pipes.

  In the above embodiment, an example of a motor pump having a relatively low power of about 100 to 750 W at a relatively low voltage of about 100 V of single phase or 200 V of three phases has been described. However, the present invention may be applied to a larger motor pump. Of course, the gist can be applied as well.

  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 figure which shows the structural example of the water supply apparatus which concerns on this invention. It is a figure which shows the structural example of the operation control apparatus of the pump of the 1st Embodiment of this invention. It is a figure which shows the structural example of the operation control apparatus of the pump of the 2nd Embodiment of this invention. It is a wave form diagram which shows the example of a control pattern of zero cross control. It is a wave form diagram which shows the example of a control pattern of phase control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Water receiving tank 12 Piping 13, 33 Motor pump 13a, 33a Motor 13b, 33b Pump 14 Pressure tank 15 Pressure switch (pressure sensor)
16 Flow sensor 17 Control panel 18 Temperature sensor 19 Float switch 20 Control device 21, 31, 32 Non-contact switch (Triac)
22 Current sensor 23, 35, 36 Zero cross detection circuit 24, 37, 38 Phase firing circuit 25, 39, 40 Phase current detection circuit 27 CPU device 28 Storage device

Claims (4)

In a water supply apparatus for controlling on / off operation of a pump integrated with the motor driven by a motor,
A temperature sensor for detecting the outside air temperature or the temperature of the pump;
Supplying current to the motor so that the motor does not rotate or slightly rotates and the motor generates sufficient heat, and based on a plurality of ignition cycles corresponding to the output of the temperature sensor , A pump operation control device configured to prevent freezing of the pump by controlling on / off of current supply , wherein the plurality of ignition cycles are based on the wave number of a voltage waveform .   The pump operation control device according to claim 1, further comprising a storage device in which the plurality of firing periods corresponding to the output of the temperature sensor are stored in advance. The on-off control of the current supply is performed so that the temperature detected by a temperature sensor that detects the temperature of the pump becomes a constant temperature that can prevent freezing of water inside the pump. Pump operation control device.   2. The operation control apparatus for a pump according to claim 1, wherein the current is controlled by controlling a phase angle of an ON state of a contactless switch by a semiconductor element.

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