EP3456973A1

EP3456973A1 - Control apparatus of a pump supplied with three-phase current and method for controlling the power supply of said apparatus

Info

Publication number: EP3456973A1
Application number: EP18194044.6A
Authority: EP
Inventors: Gino FANTOZZI
Original assignee: Trevitech Srl
Current assignee: Trevitech Srl
Priority date: 2017-09-19
Filing date: 2018-09-12
Publication date: 2019-03-20
Anticipated expiration: 2038-09-12
Also published as: DK3456973T3; EP3456973B1

Abstract

Control apparatus of a pump supplied with three-phase current, comprising - a hydraulic section comprising in turn - an inlet for the water coming from a pump with which the apparatus is associated, - an outlet for the water to be connected with a water system, - a first device sensitive to the pressure of the water interposed between said inlet and said outlet for the water adapted to verify a given pressure value of the water in the apparatus, - a second device sensitive to the flow of the water, interposed between said inlet and said outlet for the water, adapted to verify a given flow value of the water in the apparatus, - an electrical section comprising in turn - electronic means for managing the apparatus, operatively connected with said first device and said second device to control operation or switch-off of the pump based on the pressure and/or flow parameters detected, - a three-phase electrical input equipped with first terminals, one for each phase, for wiring adapted to connect said first terminals to the external three-phase power supply network, - a three-phase electrical output equipped with second terminals, one for each phase, for wiring to corresponding terminals of the pump.

Description

Technical field

The present invention relates to the field of hydraulic pump control and more in particular relates to a control apparatus of a pump supplied with three-phase current.
The present invention also relates to a method for verifying the correct power supply of a control apparatus of a pump supplied with three-phase current.

State of the art

As is known, pumps are used in water distribution systems to deliver water to utilities. Various solutions have been developed to enable adequate control of the start-up and shut-down of these pumps.
One of the most widely used solutions provides equipment comprising a chamber defined in a body, having an inlet conduit intended to be connected to the delivery side of the pump, and an outlet conduit intended to be connected to the water distribution network. A check valve is positioned in the inlet conduit while a flow switch is positioned in the outlet conduit. Differently, a pressure switch is located in the chamber. A device of this type is also called "pressure and flow regulator".
Switching on, or start-up, of the pump is controlled by the flow switch and by the pressure switch, depending on different cases (start-up for opening of utilities, shut-down for closing of utilities, shut-down due to lack of water, system operating normally, system blocked, etc.).
Generally, these pressure and flow regulating devices can only control single-phase pumps directly. In this case, the power supply from the network reaches the pump control device and from here is sent to the pump, so that the device can control its power supply (switch-on and shut-down, etc.)
Instead, in the case of three-phase pumps, the devices are not able to directly receive a 400V power supply and therefore cannot shunt said current to the pump. To be able to supply the pump it is necessary to use other ancillary devices, such as contactors, with the creation of complicated wiring. Applications with three-phase pumps are mainly assigned to the use of control boards with pressure switches or with pressure sensors, and require further complex accessories to ensure the same functions as a "pressure and flow regulator", or a single-phase pressure and flow regulator can be used, which controls the pump via a contactor entrusted with management of the three-phase power supply.
In these last cases, two types of wiring problems can often occur.
Assuming that the wiring between control device and pump can be implemented without errors, a first problem relates to the fact that the wiring between electric panel for controlling the network and the pump can be very long, with the panel at a considerable distance from the pump (often in different rooms).
Therefore, it is possible for the operator to make a mistake in the electrical connections to the panel, inverting two of the three phases of the three-phase power supply. This causes the motor of the pump to rotate in reverse direction, with the evident problems deriving therefrom. Often, the operator is not immediately aware of this problem.
Another problem related to the wiring between panel and pump located at a distance from each other, is the case in which a phase cable to the panel becomes accidentally disconnected (an occurrence that at times happens during installation or maintenance of pumps). The operator in the vicinity of the pump might not be immediately aware of the problem.

Object and summary of the invention

The aim of the present invention is to solve the aforesaid problems in control systems of prior art pumps.
Within this aim, an important object of the present invention is to produce a control apparatus of a pump supplied with three-phase current that does not require complicated wiring or external accessories.
Yet another important object of the present invention is to produce a control apparatus of a pump supplied with three-phase current that is flexible in the type of power supply possible.
A further important object of the present invention is to produce a control apparatus of a pump supplied with three-phase current that allows problems of reversal of the rotation of the motor of the pump to be prevented during wiring.
One more important object of the present invention is to produce a control apparatus of a pump supplied with three-phase current that allows problems of absence of a power supply phase of the pump to be prevented.
These and other objects, which will be more apparent below, are achieved as defined in the appended claims.
According to a first aspect, the invention relates to a control apparatus of a pump supplied with three-phase current, comprising

a hydraulic section comprising in turn
- an inlet for the water coming from a pump with which the apparatus is associated,
- an outlet for the water to be connected with a water system to be served,
- a first device sensitive to the pressure of the water interposed between said inlet and said outlet for the water adapted to verify a given pressure value of the water in the apparatus,
- a second device sensitive to the flow of the water, interposed between said inlet and said outlet for the water, adapted to verify a given flow value of the water in the apparatus,
an electrical section comprising in turn
- ∘ electronic means for managing the apparatus, operatively connected with the first device and the second device to control operation or switch-off of the pump based on the pressure and/or flow parameters detected,
- ∘ a three-phase electrical input equipped with first terminals, one for each phase, for wiring adapted to connect these first terminals to the external three-phase power supply network,
- ∘ a three-phase electrical output equipped with second terminals, one for each phase, for wiring to corresponding terminals of the pump.

Preferably, the electrical input is provided with a 400V, or a 230V, power supply, or both.
According to preferred embodiments, the apparatus according to the invention comprises a device for verifying the presence of one or more phases at the electrical input, operatively connected with the electronic means, so that, in the event of verifying the absence of at least one phase, the electronic means control disconnection of the three-phase supply to the pump.
Preferably, the device for verifying the presence of the phases at the electrical input provides for verifying the presence of voltage at one or more of the aforesaid first terminals.
Preferably, the apparatus comprises three sensors associated with the first terminals, adapted to detect, preferably continuously, the voltage on each supply line associated with the respective first terminal.
Preferably, each sensor is adapted to convert the supply voltage signal on the respective line from sinusoidal wave to low voltage wave, said converted signal is adapted to be read by a microcontroller containing an electronic program adapted to read the low voltage waves.
Preferably, with the pump not operating, i.e., switched off, the electronic program reads the consecutive low voltage waves and in the event of absence of a series of these consecutive low voltage waves, the electronic means interpret this absence as an absence of phase voltage on the corresponding line and control disconnection of the power supply from the pump, preferably deactivating a control relay of the pump, preventing problems connected to the supply without at least one phase.
Preferably, with said pump operating, the electronic means verify the voltage value of a phase and compare it with an average of the voltage of the other two phases, if this value is below a desired value of said average during a given period of time, the electronic means interpret this occurrence as absence of the phase on the corresponding line and control disconnection of the power supply from the pump, preferably deactivating a control relay of the pump, preventing problems connected to the supply without at least one phase.
Advantageously, the low voltage waves converted by the sensors are half-waves.
Preferably, the apparatus comprises a visual and/or acoustic indicator of the absence of phase, so that the operator can become aware of the absence of phase and take action to restore it.
According to preferred embodiments, the apparatus according to one or more of the preceding claims comprises a device for detecting and correcting the phase inversion to avoid reversal of the direction of rotation of the pump, comprising means for measuring the three voltages at said first terminals and a memory containing a correct sequence of values of the three voltages at the first terminals, i.e., a memory in which the mutual values of the three voltages which must be shifted from one another in a known way, are recorded; the detection device is adapted to measure the values of the three actual voltages at the first terminals and to compare them with the sequence memorized, so that in the event in which the measured values of the three voltages do not correspond to the correct sequence memorized, through switching means, the device inverts the connections between two first terminals, restoring the correct order of the phases and thus preventing inversion.
Preferably, for operation of this device for detecting and correcting the phase inversion, the apparatus comprises three sensors associated with the first terminals, adapted to detect, preferably continuously, the voltage on each supply line associated with the respective first terminal.
Preferably, each sensor is adapted to convert the supply voltage signal on the respective line from sinusoidal wave to low voltage wave; this converted signal is read by a microcontroller containing an electronic program adapted to read the low voltage waves and to compare them with the sequence of values of the three voltages at said first terminals, so that in the event in which the measured values of the three low voltage waves do not correspond to the correct sequence memorized, as specified above, through switching means, the device inverts the connections between two first terminals, restoring the correct order of the phases.
Advantageously, the low voltage waves converted by the sensors are half-waves.
In the preferred embodiment, which integrates both the aforesaid device for verifying the presence of one or more phases of three-phase power supply and the device for detecting and correcting the phase inversion, there are provided three sensors for the respective first terminals and a microcontroller, which operate for both the devices, i.e., sensors and microcontroller are common to the two devices.
With regard to hydraulic operation, according to a preferred embodiment, the apparatus is of the type comprising a chamber provided with the inlet for the water coming from the pump and the outlet for the water to be connected with the water system to be served; the first device, preferably a pressure switch, is adapted to emit a start-up signal for the pump upon reaching a preset pressure value; the second device, preferably a flow switch, is adapted to emit a start-up signal for the pump upon reaching a preset flow threshold value.
According to a preferred embodiment, the first device sensitive to the pressure of the water in the chamber comprises

sensor means, sensitive to the magnetic field, adapted to produce an effect/signal when the size of the magnetic field that surrounds said sensor means exceeds a given operating value, said effect/signal being correlated with the drive of said pump,
a body sensitive to the pressure in said chamber, which can move along a direction as a function of the pressure value in said chamber so that a portion thereof moves toward or away from said sensor means based on the pressure in said chamber,
magnetic means integral with said portion of moving body, adapted to produce a magnetic field, defined as primary magnetic field; the value of the primary magnetic field that surrounds said sensor means being correlated to the pressure value in said chamber, the position of said body, i.e., the distance of said magnetic means from said sensor means, being a function of the pressure in said chamber.

Preferably, said sensor means, sensitive to the magnetic field, comprise a reed device. Preferably, said magnetic means comprise at least a magnet integral with said body.
Preferably, said first device sensitive to the pressure of the water comprises means adapted to produce at least a secondary magnetic field, distinct from the primary magnetic field produced by said magnetic means, adapted to surround said sensor means, said at least a secondary magnetic field surrounding said sensor means with a value that does not produce said effect/signal; the operating value that produces said signal/effect being given by the sum of the value of secondary magnetic field that surrounds said sensor means and of the value of primary magnetic field that surrounds the same sensor means.
Preferably, said means for producing said at least one secondary magnetic field comprise at least one coil or inductance adapted to generate a magnetic field that surrounds said reed device. Preferably, said means for producing said at least one secondary magnetic field comprise means for varying the current circulating along said coil/inductance associated with said electronic means.
Preferably, the electronic means comprise an electronic card in which there is arranged said reed device and at least one coil generating said at least one secondary magnetic field arranged on the same side of said card with respect to said reed device.
According to another aspect, the invention relates to a method for verifying the correct power supply of a control apparatus of a pump supplied with three-phase current, equipped with a three-phase electrical input equipped with first terminals, one for each phase, for wiring adapted to connect the first terminals to the external three-phase power supply network and with a three-phase electrical output equipped with second terminals, one for each phase, for wiring to corresponding terminals of the pump; the method comprises

verifying the presence of the phases at the respective first terminals and, in the event of the absence of at least one phase, disassociating the control apparatus from the pump, preferably by deactivating the control relay of the pump, and/or
verifying the theoretical direction of rotation of the motor of the pump and correcting this theoretical direction of rotation in the event of rotation in the opposite direction to that established.

Preferably, according to a preferred embodiment, the method comprises the conversion, for each phase, of the supply voltage from sinusoidal wave to low voltage half-wave and its processing via electronic program.
Preferably, if the pump is not operating, the method comprises the step of reading, for each phase, the consecutive half-waves and in the event of absence of a series of these consecutive half-waves, disconnection of the power supply from the pump is controlled, preferably deactivating a control relay of the pump. Otherwise, if the pump is operating, the method comprises a step of verifying, for each phase, the value of the voltage of a half-wave and comparing it with the average of the voltage of the half-wave of the other two phases: if this value is lower than a desired value of said average during a given period of time, the method interprets this occurrence as absence of the phase on the corresponding line and controls disconnection of the power supply from the pump, preferably deactivating a control relay of the pump.
Preferably, the method comprises a step of initial memorization of a correct sequence of values of the three voltages at the first terminals to which the correct rotation of the motor of the pump corresponds, and a step of comparing the voltage values of the half-waves with said sequence of values of the three voltages at said first terminals; in the event in which the measured values of the three half-waves do not correspond to the correct sequence memorized, the method inverts the connections between the two first terminals, restoring the correct order of the phases.

Brief description of the drawings

Further characteristics and advantages of the invention will become more apparent from the following description of a preferred but non-exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Fig. 1 represents a schematic view of part of the apparatus with indication of the electrical connections to the power supply network and to the pump to be controlled;
Fig. 2 is a front view of an apparatus according to the invention;
Fig. 3 shows the star connection diagram of the supply lines of the pump coming from the apparatus according to the invention, to allow a 400 Vac power supply;
Fig. 4 shows the delta connection diagram of the supply lines of the pump coming from the apparatus according to the invention, to allow 400 Vac power supply;
Fig. 5 shows the sinusoidal shape of the three phases of the voltage of the three-phase power supply of the apparatus; the three waves are shifted from one another by 120°;
Fig. 6 shows a single sinusoidal phase of the three-phase current;
Fig. 7 shows the conversion into single half-wave of the phase of Fig. 6;
Fig. 8 shows a schematic section of the apparatus according to the invention.

Detailed description of an embodiment of the invention

With reference to the previously cited figures, a control apparatus of a pump supplied with three-phase current according to the invention is indicated as a whole with 10, while the pump is indicated as a whole with 11.
This apparatus 10 comprises a casing 12, defined inside which is a hydraulic section 13 and an electrical section 14.
According to a known embodiment, such as the one described in the European patent EP2653725 by the same applicant, which is incorporated herein by reference in its entirety, the hydraulic section 13 comprises a chamber 15 provided with the inlet 16 for the water coming from the pump 11 and the outlet 17 for the water to be connected to the water distribution system to be served.
The hydraulic section 13 further comprises a first device 19 sensitive to the pressure of the water interposed between the inlet 16 and the outlet 17, i.e., in the chamber 15, such as a pressure switch, adapted to verify a given pressure value of the water in the chamber.
The hydraulic section 13 further comprises a second device 20 sensitive to the flow of the water, such as a flow switch, interposed between the inlet 16 and the outlet 17, adapted to verify a given flow value of the water in the apparatus; in particular the flow switch is provided at the outlet 17.
The pressure switch 19 is adapted to emit a start-up signal for the pump upon reaching a preset pressure value; the flow switch 20 is adapted to emit a start-up signal for the pump upon reaching a preset flow threshold value, as better described below, in the same way as EP2653725 .
The electrical section 14 comprises electronic means 22 (schematized by a dot-dash line in Fig. 8) for managing the apparatus, operatively connected with the first device 19 (pressure switch) and the second device 20 (flow switch) to control operation or switch-off of the pump based on the pressure and/or flow parameters detected, in a known way.
The electrical section 14 comprises accesses 23 and 24 for the passage of wiring (to be operatively connected with the electronic means) from the external power supply Q (such as an external electrical panel positioned at a distance from the pump) toward the apparatus and from the apparatus toward the pump.
In an innovative way, the electrical section 14, inside the casing, comprises a three-phase electrical input 25 equipped with three first terminals 26, 27 and 28, one for each phase, for first wiring indicated with L. This wiring L is, as known, formed by three cables each carrying a phase, each phase indicated respectively with L1, L2 and L3 (for example, L1 connects the first terminal 26 with a corresponding terminal Q1 to the panel Q, L2 connects the first terminal 27 to the terminal Q2 and L3 connects the first terminal 28 to the terminal Q3). M1 indicates a first ground terminal.
Moreover, the electrical section 14, inside the casing, comprises a three-phase electrical output 29 equipped with second terminals 30, 31 and 32, one for each phase, for second wiring indicated with UVW to corresponding terminals of the pump U1, V1 and W1. M2 indicates a second ground terminal.
The electrical input and the electronic components are dimensioned to receive both a voltage of 400 Vac, and a voltage of 230 Vac, i.e., the device can be supplied either with three-phase voltage at 230 Vac and 400 Vac. In this case the wiring of the pump (delta for three-phase 230 Vac - star for 400 Vac), must be implemented as shown in Figs. 3 and 4.
Fig. 5 shows the three sinusoidal waves that represent the three-phase voltage, shifted by 120°.
A sensor K is associated with each first terminal 26, 27 and 28 and is adapted to continuously detect the voltage on each supply line L1, L and L3 associated with the respective first terminal.
A microcontroller 40 is associated with the sensors K. Sensors and microcontroller are part of the electronic means 22.
Each sensor K is adapted to convert the supply voltage signal on the respective line L from sinusoidal wave G to low voltage half-wave H, as simplified in Figs. 6 and 7 (Fig. 7 shows the conversion to single half-wave; in other embodiments conversion to double half-wave or another type of conversion may be possible).
Advantageously, there is provided a device 50 for verifying the presence of one or more phases L in the three-phase electrical input 25, operatively connected with the electronic means 22, so that, in the event of verifying the absence of at least one phase, the electronic means control disconnection of the three-phase supply to the pump. In particular, the device for verifying the presence of the phases 50 verifies the presence of voltage at the first terminals 26, 27 and 28.
This verifying device 50 in practice comprises the sensors K and the microcontroller 40 and an electronic program E contained in the microcontroller that reads the signals converted into low voltage half-waves by the sensors K.
More in particular, the device 50 operates in two situations: with the pump not operating, i.e., switched off, and with the pump operating.
In the first case, with the pump not operating, the electronic program reads consecutive half-waves and in the event of absence of a series of these consecutive low voltage waves, the electronic means 22 interpret this absence as an absence of phase voltage on the corresponding line L and control disconnection of the power supply from the pump, deactivating a control relay of the pump (not indicated for simplicity in the figures), preventing problems connected to the supply without at least one phase.
With the pump operating, the electronic means verify the voltage value of a half-wave relating to a phase L and compare it with an average of the voltage of the half-waves of the other two phases, if this value is below a desired value of the average during a given period of time, the electronic means interpret this occurrence as absence of the phase on the corresponding line L and control disconnection of the power supply from the pump, deactivating a control relay of the pump.
The apparatus 10 comprises an indicator 51, for example an LED, of the absence of phase, so that the operator can be made aware of the absence of phase and take action to restore it.
In practice, detection of the absence of phase by the device 50 is a verification that is carried out for each of the three power supply lines (L1, L2, L3) of the apparatus 10.
It is based on microcontroller processing of the signals coming from the three sensors K that continuously detect the voltage on each of the three supply lines.
Starting from the fact that the absence of phase can occur in two different situations (the first with the pump switched off and the second with the pump operating), the electronic program E is provided with two verification systems, the first suitable for the condition with the pump switched off, and the second suitable for the condition with the pump operating; the two verifications are carried out simultaneously and continuously, and, if the result is positive, they are both interpreted as a disconnection of phase:

The first disconnection occurs when the voltage of any one of the three lines L is absent for a given period of time (fractions of second): a sensor is provided for each of the three phases to convert the sinusoidal wave supply voltage into a low voltage half-wave signal, which is sent to a dedicated input of the microcontroller 40; by reading this signal, through the electronic program, in the event of detection of the absence of a series of consecutive half-waves, this is interpreted as absence of this phase.
The second disconnection occurs when the voltage of any of the three lines L is much lower than the average of the other two for a given period of time (in the order of seconds, variable according to pump model, being based on the voltage measurement regenerated by the disconnected phase of the motor of the pump). In the event of detection of absence of phase the device 50 takes action by deactivating the control relay of the pump and the activating the alarm "absence of phase" (for example, rapid flashing of a red LED associated with the indicator 51).

Advantageously, the apparatus 10 comprises a device 60 for detecting and correcting the phase inversion to avoid reversal of the direction of rotation of the motor of the pump.
This device 60 comprises means for measuring the three voltages at said first terminals 26, 27 and 28 and a memory 61 containing a correct sequence of values of the three voltages L at said first terminals, i.e., a memory in which the mutual values of the three voltages, which must be shifted from one another in a known way, are recorded; the detection device 60 is adapted to measure the values of the three actual voltages at the first terminals and compares them with the sequence memorized, so that in the event in which the measured values of the three voltages do not correspond to the correct sequence memorized, through switching means, such as switching devices of known type (not indicated for simplicity in the figures) the device inverts the connections between two first terminals, restoring the correct order of the phases and thus avoiding inversion.
In practice, in this example the device for detecting and correcting phase inversion 60 uses the three sensors K (these are the aforesaid measuring means) associated with the first terminals 26, 27 and 28, which therefore detect the voltage on the lines L and convert them into low voltage half-waves signals, and the microcontroller 40 that reads the converted signals and through an electronic program D (which in other embodiments could be integrated in the program E) loaded therein compares them with the sequence memorized of the correct voltages and, in the event in which the measured values of the three half-waves do not correspond to the correct sequence memorized, as specified above, controls inversion of the connections to the terminals.
A practical example is set down below. Let us assume that the second wiring UVW between the second terminals 30, 31 and 32 of the three-phase electrical output 29 and the terminals of the pump U1, V1 and W1 is correct. If the operator erroneously connects the connection L1 (which should be connected to Q1) with the connection Q2 (and therefore connects L2 with Q1), phase inversion occurs. The device 60 detects that phases L1 and L2 at the terminals 26 and 27 have a different value to the theoretical value memorized and therefore knows that phase inversion has occurred and performs switching between the two first terminals 26 and 27, restoring the correct phase. If all three phases L do not have the expected value at the first terminals (for example, the pairs L1-Q2, L2-Q3 and L3-Q1 have been connected), from a practical point of view there is no reversal of rotation of the motor and therefore the device 60 does not control any switching.
Summarizing, detection of phase inversion is performed on the three supply lines of the device (L1, L2, L3). It assumes correctness of the connections on the three output phases to the motor of the pump. It is based on the measurement, through microcontroller processing, of the sequence of the signals coming from the three sensors K that continuously detect the voltage on each of the three supply lines L1, L2 and L3; as stated above, for each of the three phases the sensor K converts the sinusoidal wave supply voltage into a low voltage half-wave signal, which is sent to a dedicated input of the microcontroller; through reading this signal, via the electronic program, the order of the three half-waves, which corresponds to the sequence of the three power supply phase voltages, is detected; when the sequence does not comply with the predetermined order, the apparatus 10 takes the following actions: it ensures that the control relay of the motor (three-phase) remains deactivated; then, through a second pair of relays, it inverts the incorrect phases (for example L1 with the phase L2), switching the contacts at the terminals; finally, it activates the control relay thereby starting the motor in the correct direction. The response time is in the order of a couple of seconds and no notification is given in the event of phase inversion.
The invention also relates to a method for verifying the correct power supply of the control apparatus 10 of the pump supplied with three-phase current, which comprises

verifying the presence of the phases at the respective first terminals and, in the event of the absence of at least one phase, disassociating the control apparatus from the pump, for example by deactivating the control relay of the pump, and
verifying the theoretical direction of rotation of the motor of the pump and correcting this theoretical direction of rotation in the event of rotation in the opposite direction to that established.

A conversion, for each phase, of the supply voltage from sinusoidal wave to low voltage half-wave and its processing via electronic program is provided.
If the pump is not operating, the consecutive half-waves are read for each phase, and in the event of absence of a series of these consecutive half-waves, disconnection of the power supply from the pump is controlled, deactivating a control relay of the pump. Differently, if the pump is operating, for each phase, the voltage value of a half-wave is verified and compared with the average of the voltage of the half-wave of the other two phases: if this value is below a desired value of said average during a given period of time, this means there is an absence of the phase on the corresponding line and disconnection of the power supply from the pump is controlled, deactivating a control relay of the pump.
With regard to verification of the theoretical direction of rotation of the motor of the pump and correction of this theoretical direction of rotation in the event of rotation in the opposite direction to that established, the method comprises an initial (factory) memorization step of a correct sequence of values of the three voltages at the first terminals to which correct rotation of the motor of the pump corresponds, and a step of comparing the voltage values of the half-waves with said sequence of values of the three voltages memorized; in the event in which the measured values of the three half-waves do not correspond to the correct sequence memorized, the connections between two said first terminals are inverted, restoring the correct order of the phases.
General operation of the apparatus 10 is described below.
The apparatus 10 according to the invention can be mounted directly on the pump or between this and the hydraulic network to be served.
When the tap is opened (i.e. water is requested from the water distribution network to be served), the apparatus starts the pump that continues to operate as long as the tap is open. When the tap is closed, the device restores the maximum pressure in the system, shuts down the pump and returns to the stand-by position. If there is no water at the pump intake.
The device integrates a pressure switch and a flow switch.
Start-up of the motor of the pump is determined by the presence of flow (start-up via flow switch) or by the reduction in pressure (start-up via pressure switch).
The pump continues to run for the whole of the time that the flow switch is raised as a result of the flow that passes through the device.
The pump shuts down a few seconds after the flow switch has dropped into its seat.
In the absence of flow the pressure switch allows the device to discriminate the condition for pump shut down:

Flow switch lowered, pressure switch in the condition of pressure present in the system => Pump stopped, ready to start operating again.
Flow switch raised, pressure switch in the condition of absence of pressure in the system => Pump stopped to protect against running dry.

The dual three- phase 230 and 400 Vac power supply allows the device to be used in any application and above all any geographical area, as in countries that use single-phase 115Vac supply voltage the standard three-phase voltage is usually 230Volt.
Protection against the absence of phase is provided when the device detects the absence of one of the three supply phases and consequently the pump shuts down immediately to protect the motor from breakage due to the incorrect power supply.
Protection against phase inversion is provided when, after installation, the device detects that any one of its supply phases has been inverted. Automatically and immediately, via a relay, the device restores the correct power supply to the motor, preventing it from running in reverse direction.
An example of the hydraulic components of the "pressure and flow regulator" indicated in the figures is described below.
The casing 11 comprises a second chamber 115, hydraulically isolated from the chamber 15 by means of a wall 116. This second chamber houses therein at least part of the electronic means for controlling and managing the apparatus, and in particular a card 117 with electronic components mounted thereon, and is part of the electronic means 22.
The flow switch 20 comprises, for example, a slider 119 arranged slidingly in the vertical portion of the outlet 17 and which can be moved upward by the flow of water, when present, opposing its weight force. When there is no flow, the slider 119 remains lowered to close the outlet 17. The head 119A of the slider has a given hydraulic seal with the outlet 17 and is dimensioned so that a minimum predetermined flow rate corresponds to the pressure jump sufficient to overcome the weight of the slider.
The flow switch also comprises a first magnet 120A fixed on one side of the slider 119 close to the wall 116, and a first reed switch 120B arranged on the card 117. When the flow is below the preset threshold flow value that enables lifting of the slider, the magnet interacts with the reed switch, which is closed. When the slider is lifted, the magnet disengages magnetically from the switch, which opens, resulting in the generation of a signal enabling pump start-up.
On the vertical portion of the inlet 16 there is provided a check valve 120 for water from the first chamber toward the pump.
In the first chamber 15 there is provided a pressure switch 19, adapted to emit a start-up signal for the pump upon reaching a preset value defined "cut-in pressure".
The pressure switch 19 comprises sensor means 122, better described below, sensitive to the magnetic field and adapted to produce an effect or a signal when the size of the magnetic field that surrounds these sensor means exceeds a given operating value, corresponding to the cut-in pressure, and therefore the effect or signal generated by these sensor means 122 is correlated with the drive of the pump.
The pressure switch 19 also comprises a body 123 sensitive to the pressure in the chamber 15, which can move along a direction as a function of the pressure value in this chamber 15 in such a manner that a portion 123A thereof moves toward or away from the sensor means 122 based on the pressure in the chamber.
For example, this body 123 is a stem constrained to translate in a predetermined direction (for example horizontal). According to a configuration of known type, this stem 123 is fixed to a membrane 124 and interacts with a spring 125 in such a manner that the stem is adapted to take an axial position inside the chamber as a function of the pressure present in the chamber. When the pressure increases, the stem is drawn by the membrane in a direction of compression of the spring 125, moving away from the wall 116 that divides the first chamber from the second chamber with the card 117 and the sensor means 122; when the pressure drops, the spring 125 thrusts the stem in the opposite direction (toward the wall 116).
It can be noted how the terminal end 123A of the stem 123 is adapted to enter a recess 116A defined on the wall 116, which extends inside the second chamber 115; the card 117 has a through hole to enable arrangement of the recess 16A.
The pressure switch further comprises magnetic means 126 integral with the portion of the stem 123 that moves toward the sensor means 122. These magnetic means 126 are adapted to produce a magnetic field, hereinafter defined as primary magnetic field.
Preferably, the sensor means 122 can consist of a second reed device (hereinafter also indicated with the number 122) and the magnetic means 126 can consist of a magnet (hereinafter also indicated with the number 126), in such a manner that when the magnet 126 moves toward the second reed device, the reed switch is closed and a start-up signal for the pump is generated. It is clear that the value of the primary magnetic field that surrounds the sensor means 122, i.e., the reed device, is correlated to the pressure value in the chamber, as the position of the stem 123 with respect to the reed device 122, i.e., the distance of the magnet 126 from this reed device, is a function of the pressure in the chamber.
It is understood that the drawing only shows possible non-limiting embodiments of the invention, which can vary in forms and arrangements without however departing from the scope of the concept on which the invention is based. Any reference numerals in the appended claims are provided purely to facilitate the reading thereof, in the light of the above description and accompanying drawings, and do not in any way limit the scope of protection.

Claims

Control apparatus of a pump supplied with three-phase current, comprising
- a hydraulic section comprising in turn

- an inlet for the water coming from a pump with which the apparatus is associated,

- an outlet for the water to be connected with a water system,

- a first device sensitive to the pressure of the water interposed between said inlet and said outlet for the water adapted to verify a given pressure value of the water in the apparatus,

- a second device sensitive to the flow of the water, interposed between said inlet and said outlet for the water, adapted to verify a given flow value of the water in the apparatus,

- an electrical section comprising in turn
- electronic means for managing the apparatus, operatively connected with said first device and said second device to control operation or switch-off of the pump based on the pressure and/or flow parameters detected,

- a three-phase electrical input equipped with first terminals, one for each phase, for wiring adapted to connect said first terminals to the external three-phase power supply network,

- a three-phase electrical output equipped with second terminals, one for each phase, for wiring to corresponding terminals of the pump.
Apparatus according to claim 1, comprising a device for verifying the presence of one or more phases in said electrical input, operatively connected with said electronic means, so that, in the event of verifying the absence of at least one phase, said electronic means are adapted to control disconnection of the three-phase supply to said pump.
Apparatus according to claim 2, wherein said device for verifying the presence of the phases at the electrical input provides for verifying the presence of voltage at one or more of said first terminals.
Apparatus according to claim 3, comprising three sensors associated with said first terminals, adapted to detect, preferably continuously, the voltage on each supply line associated with the respective first terminal.
Apparatus according to claim 4, wherein each sensor is adapted to convert the supply voltage signal on the respective line from sinusoidal wave to low voltage wave, said converted signal being adapted to be read by a microcontroller containing an electronic program adapted to read the low voltage waves.
Apparatus according to claim 5, wherein, with said pump not operating, i.e., switched off, said electronic program being adapted to read the consecutive low voltage waves and in the event of absence of a series of these consecutive low voltage waves, the electronic means interpret this absence as an absence of phase voltage on the corresponding line and control disconnection of the power supply from the pump, preferably deactivating a control relay of the pump.
Apparatus according to claim 4, 5 or 6, wherein, with said pump operating, said electronic means verify the voltage value of a phase and compare it with an average of the voltage of the other two phases, if this value is below a desired value of said average during a given period of time, said electronic means interpret this occurrence as absence of the phase on the corresponding line and control disconnection of the power supply from the pump, preferably deactivating a control relay of the pump.
Apparatus according to one or more of claims 5, 6 or 7, wherein said low voltage waves are half-waves.
Apparatus according to one or more of the preceding claims, comprising a visual and/or acoustic indicator of the absence of phase.
Apparatus according to one or more of the preceding claims, comprising a device for detecting and correcting the phase inversion to avoid reversal of the direction of rotation of the pump, comprising means for measuring the three voltages at said first terminals and a memory containing a correct sequence of values of the three voltages at said first terminals, said detection device being adapted to measure the values of said three voltages at said first terminals and to compare them with said sequence, so that in the event in which the measured values of the three voltages do not correspond to the correct sequence memorized, through switching means, said device inverts the connections between two said first terminals, restoring the correct order of the phases.
Apparatus according to claim 10, comprising three sensors associated with said first terminals, adapted to detect, preferably continuously, the voltage on each supply line associated with the respective first terminal.
Apparatus according to claim 11, wherein each sensor is adapted to convert the supply voltage signal on the respective line from sinusoidal wave to low voltage wave, said converted signal being adapted to be read by a microcontroller provided with an electronic program adapted to read the low voltage waves and to compare them with said sequence of values of the three voltages at said first terminals, so that in the event in which the measured values of the three low voltage waves do not correspond to the correct sequence memorized, through switching means, said device inverts the connections between two said first terminals, restoring the correct order of the phases.
Apparatus according to claim 12, wherein said low voltage waves are half-waves.
Apparatus according to claims 4, 5, 11 and 12, wherein said three sensors and said microcontroller are common for said device for verifying the presence of one or more phases and for said device for detecting and correcting the phase inversion.
Apparatus according to one or more of the preceding claims, wherein said three-phase electrical input is supplied at 400V and/or at 230V.
Apparatus according to one or more of the preceding claims, comprising a chamber provided with said inlet for the water coming from the pump and said outlet for the water to be connected with the water system; said first device, preferably a pressure switch, being adapted to emit a start-up signal for the pump upon reaching a preset pressure value; said second device, preferably a flow switch, being adapted to emit a start-up signal for the pump upon reaching a preset flow threshold value.
Method for verifying the correct power supply of a control apparatus of a pump supplied with three-phase current, equipped with a three-phase electrical input equipped with first terminals, one for each phase, for wiring adapted to connect said first terminals to the external three-phase power supply network and with a three-phase electrical output equipped with second terminals, one for each phase, for wiring to corresponding terminals of the pump, said method comprising
- verifying the presence of the phases at the respective first terminals and, in the event of the absence of at least one phase, disassociating said control apparatus from the pump, preferably by deactivating the control relay of the pump, and/or

- verifying the theoretical direction of rotation of the motor of the pump and correcting this theoretical direction of rotation in the event of rotation in the opposite direction to that established.
Method according to claim 17, comprising the conversion, for each phase, of the supply voltage from sinusoidal wave to low voltage half-wave and its processing via electronic program.
Method according to claim 18, wherein, if the pump is not operating, it comprises the step of reading, for each phase, the consecutive half-waves and in the event of absence of a series of these consecutive half-waves, controlling disconnection of the power supply from the pump, preferably deactivating a control relay of the pump.
Method according to claim 18, wherein, if the pump is operating, comprising the step of verifying, for each phase, the voltage value of a half-wave and comparing it with the average of the voltage of the half-wave of the other two phases, if this value is below a desired value of said average during a given period of time, the method interpreting this occurrence as absence of the phase on the corresponding line and controlling disconnection of the power supply from the pump, preferably deactivating a control relay of the pump.
Method according to claim 18, comprising a step of initial memorization of a correct sequence of values of the three voltages at said first terminals to which the correct rotation of the motor of the pump corresponds, and a step of comparing the voltage values of the half-waves with said sequence of values of the three voltages at said first terminals; in the event in which the measured values of the three half-wave do not correspond to the correct sequence memorized, said method inverting the connections between two said first terminals, restoring the correct order of the phases.