JP2013522531A - Dosing pump with piston stroke control device - Google Patents

Abstract

An apparatus for controlling the stroke of a piston 3 of a metering pump, comprising an electromagnet 1, which is formed by a fixed part and a movable part fixed to the piston 3, and in this case, for each displacement of the piston Is a device in which various values of the inductance of the electromagnet 1 and thus various values of the piston stroke itself correspond.
[Selection] Figure 1A

Description

  The present invention basically relates to the field of electromagnetically driven metering pumps for metering liquids.

The metering pump is used to meter various types of additive liquids by making volumetric adjustments for the liquid delivered in each cycle. Such metering pumps are devices that are widely used in many scenes, both industrial and home. As these uses, for example,
Drinking water treatment,
Public water pool and private water pool,
Car wash equipment,
Laundry,
electrical equipment,
Chemical industry,
cooling tower,
Dripping fertilization,
Agricultural food industry,
other,
Is mentioned.

  Before entering into the details of the operation of a typical metering pump, the metering takes place by pulsing a mechanical member (called "membrane") in the so-called pump body and this mechanical member However, it should be noted that the liquid to be metered, pushed by the piston, is injected into the supply path of the pump body, which is prepared for the purpose. In this case, the liquid to be metered is directed to the system being processed while overcoming the counter pressure present in the conduit into which it is injected.

  Thus, the primary member to provide the necessary force to effectively mix the metered liquid with the liquid to be treated is the piston. The piston periodically constitutes a component designed to move a membrane that draws liquid from the suction pipe into the pump body and injects this liquid into the supply pipe.

  The piston is driven by an electromagnet. The electromagnet is therefore a fundamental part of the pump. The electromagnet includes a fixed portion that houses an armature and a movable portion (referred to as a “plate”) that is fixed to the piston.

  The plate essentially constitutes a closing element towards the magnetic flux of the electromagnet, which acts to pull the plate back towards the stationary part where the electromagnet stays, and so on. Thus, it should be noted that displacement is caused.

  Thus, in other words, the electromagnet allows the conversion of electrical energy into mechanical energy in order to get work and move the liquid.

  Thus, the electrical and mechanical properties of the metering pump depend on how the electromagnet is designed, driven and controlled. The electronic card in the pump is nothing but the one that supplies electrical energy to the electromagnet and manages the electrical energy supplied to the electromagnet in the best way.

  Thus, it is clear that the higher the efficiency of the metering pump, the better the control. This is a very important factor because whenever the metering performed in the system being processed is established, the metering needs to be performed continuously with minimal electrical energy consumption.

  In fact, depending on the application, a metering pump that supplies a small amount of liquid at each infusion is required, and thus a large number of infusions are required to be able to meter the volume required to perform the process. It is said. The goal can be achieved by adjusting the piston stroke to cause a constant injection. By adjusting the stroke, the liquid volume can be appropriately metered. Thus, the present invention is based on the control of the appropriate physical quantity that can be reduced to the controlled variable, i.e. the injection volume, where the input variable is the current supplied to the electromagnet in the case of the present invention. Enter the field of closed-loop regulation systems regulated by systems by feedback.

  Metering pumps have progressed over time, but have followed the evolution of electromagnets and various drive and control systems. The goal of the study was to prevent the following drawbacks.

  Waste of energy. This has been attributed in the past to the fact that a voltage pulse with a constant duration was applied to the electromagnet, no matter how much force was needed to overcome the back pressure of the system. In fact, the lower the pressure of the system in which the liquid to be processed is, the greater the waste of energy, as a result the less thrust is required to overcome the counter pressure.

  Excessive heating of equipment, especially excessive heating of electromagnets. This has been attributed in the past to the fact that the energy supplied has not been controlled on the basis of the overcoming force that is related to what was explained in the previous point. Along with this, the performance deteriorated due to the increase in the resistance of the armature over the medium and long term.

  Reduced service life. This was caused by medium to high operating temperatures of both electronic components and electromagnets.

  The need to have mechanical means for piston stroke calibration to obtain the desired pump capacity. As a result, it was necessary to introduce a shim washer into the electromagnet.

  The need to provide a mechanical system for stroke adjustment that limits the piston stroke only mechanically and thus reduces the injection volume without proportionally reducing the electrical energy supplied to the instrument. This fact implies that for the same injection, the level of energy consumption is constant even when the supply of product is minimal. This type of equipment is not characterized by a high level of efficiency.

  From U.S. Patent Application Publication No. 20090206184, for injection into a combustion chamber for control of a fuel injector using a sensor that slides in an accessory channel and detects a displacement of a movable piston different from the needle valve. The system is known. The purpose of this system is to change the shape of the injection pulse in the event of any malfunction (blocking in the on or off position), if the nozzle, injector or combustion chamber geometry deteriorates In some cases, the displacement signal of the accessory piston is monitored and processed to control the operation of the injector. In US 20090206184, the displacement of the piston is dependent on the pressure difference that exists between the two ends of the piston itself. That is, the top pressure is dependent on the supply pressure generated upstream of the injection system, and the bottom pressure is dependent on the pressure of the “pre-injection” chamber whose volume is determined by the associated geometric structure. The aforementioned pressure difference is clearly determined by the supply pressure, the supply frequency, and the state of the injector. In fact, the three states of the injector can be distinguished. That is, the three states are a closed state (“off”), an intermediate state (“blocked”), and an open state (“on”). These are respectively defined as the following states. Off: The nozzle is closed by a needle, the pre-injection chamber is in communication with the source, and the end of the slidable piston is exposed to the same pressure. Blocking: The nozzle is still closed and the supply duct is geometrically closed, thereby separating the pre-injection chamber and the source. On: The flow path to the nozzle is open, the pre-injection chamber is not in communication with the supply source, and the movable piston is displaced downward according to the negative pressure generated by opening the nozzle port.

  The present invention has a series of significant differences compared to that described in the injection system of U.S. Patent Application Publication No. 20090206184. In this injection system, the feed pump is completely separated from the injector, regardless of the injector or the type of control being performed. In fact, in the present invention, the pump operation and the injection operation are performed by the same device including a magnet, a piston, and a diaphragm that are energized and controlled. The diaphragm pushes liquid into the duct, and the opening / closing of the duct is ensured by a specific valve that operates exclusively for hydrodynamic effects.

  Furthermore, U.S. Patent Application Publication No. 20090206184 describes a control device obtained by an auxiliary piston that is displaced in response to changes in injection conditions. This displacement is detected by a specific sensor. The displacement data is processed to correct upstream feed conditions and restore the pre-injection chamber volume and pressure.

  Instead, according to the present invention, the position of the piston itself is determined by measuring the variation in impedance that occurs in the magnet's electrical circuit itself in response to the variation in the position of the pump piston, from which a predetermined fluid flow is determined. It is possible to control the associated energy in order to guarantee the flow rate. In other words, it is possible to control the displacement of the device by measuring the electrical properties of the device without having to use indirect measurements of other movable members.

  Finally, in US 20090206184, the position of the auxiliary piston in a particular structure can be corrected by an additional actuator. The displacement data detected by the sensor is in this case also processed to restore the preinjection chamber volume and pressure. Instead, in the present invention, it is possible to vary the position of the pump piston by processing the measurement of the impedance of the magnet's electrical circuit, thus ensuring a predetermined flow rate of the fluid. In this way, it is possible to control the displacement of the device by acting directly on the pump piston without using an additional actuator in the preliminary injection chamber.

  In conclusion, if we try to find similarities between the two systems, we can say: In the injection system of U.S. Patent Application Publication No. 20090206184, a pump device, an injector, an auxiliary piston, a motion sensor, and an actuator of the auxiliary piston are considered as different members, and a device (sensor) added to the pump member is considered. Control is performed based on the signal detected using the + actuator). In contrast, the innovative system described in this patent specification manages only the pumping device through magnet measurement and electrical control. That is, the pump assembly is a sensor and actuator with no additional members.

  Further, from WO 2007/007365 pamphlet, the fluctuation corresponding to the current curve is generated in relation to the fluctuation of the inductance, and the contact point between the plate and the core of the electromagnet is specified by the analysis performed by the electronic circuit. Metering pumps are known. In this way, the device can identify the end-of-travel of the piston and thus interrupt the drive of the electromagnet, thereby preventing wasted energy and thus , Wasteful waste of heat that threatens product performance is prevented.

  Furthermore, the present invention contemplates the measurement of the current used to calculate the impedance, but unlike that shown in WO 2007/007365, the arrival point of the plate, and thus Not limited to shutting off the stroke end, set the relationship between the inductance value and the position taken by the piston during the stroke, and determine at which position the piston stroke is cut off based on the settings entered by the user To do. With the present invention, it is possible to control the piston stroke with 1 / 100th accuracy, thus controlling the pump capacity for each single injection of additive liquid.

  German utility model 202005013089 relates to an electronic metering pump which controls the piston stroke in order to determine the amount of energy required for the device to properly perform its work. From the analysis of the above literature, this electronic metering pump is an electronic circuit that adjusts the piston stroke by a mechanical system, detects the stroke set by the user with the aid of an optical sensor, and drives the electromagnet using the control signal Results in having an energy content equivalent to the work that the pump is to perform.

  Unlike the German utility model 202005013089, the present invention reduces the waste of energy and saves the current to the electromagnet in order to keep it in a mechanical system for controlling the piston stroke. It is not limited to control, it drives the solenoid with the correct amount of current, controls its advancement by calculating impedance, and its interruption at a well-defined position that can be set by calibration of the electronic circuit. decide. In other words, in the present invention, the pump capacity is not mechanically controlled, all of which drive the electromagnet and control the stroke end of the piston, thus determining the pump capacity with 1 / 100th accuracy. It is left to the system.

  WO 03/023226 describes an electromagnet metering pump for injecting pharmaceuticals into the human body. In this electromagnet metering pump, the device is supplied with energy from a battery and the device is not connected to a supply power source. For this reason, the invention described in said document relates to a system having the advantage of ensuring an accurate metering with minimal use of electrical energy and extending the useful life of the battery.

  From the analysis of WO 03/023226, at the moment when energy is supplied to the pump by the activation of the switch and the signal, the capacitor functioning as an accumulator is charged for a predetermined period, and the control circuit controls the control signal 34. It can be seen that the switch remains in that state until it activates the solenoid that determines the start of infusion delivered by the pump. The principle may seem common, but in practice, the charging / discharging of the capacitor is controlled “smartly”, and at the moment of driving, the minimum energy required for proper operation of the pump is drawn out, Energy savings are achieved.

  In conclusion, the system described in WO 03/023226 controls the gradual variation of voltage and current to determine the appropriate amount of energy used for the solenoid.

  Unlike WO 03/023226, the present invention is based on stroke control for instantaneously correcting the pump injection rate. Where appropriate, the present invention is not limited to determining whether the stroke end has been reached, but is controlled in real time based on what is occurring in the magnet, the impedance is calculated, and the piston The exact position where the stroke should stop is determined. According to a characteristic characteristic of the invention, the solenoid not only functions as an actuator but also functions as a sensor of the system.

  The main object of the present invention is to overcome all the drawbacks listed above by proposing a new, latest generation metering pump with low energy consumption and high performance.

  The above is in accordance with the present invention for controlling the value of the impedance of an electromagnet (advantageously, an amount that is less sensitive to external factors such as operating temperature, mechanical wear, and supply voltage). This is achieved by proposing an innovative adjustment of the underlying stroke (dynamic variation of the injection volume).

  The above types of metering pumps improve current performance, reduce the level of energy consumption to a minimum, and at the same time depend solely on the electromagnet geometry without the use of mechanical devices that tend to wear out It is designed to be interchangeable with existing equipment by ensuring accurate metering based on piston stroke control by physical quantity measurement.

FIG. 2 is an enlarged detail view showing an axial section and a void of a metering pump forming the subject of the present invention and fitted with an electromagnet. 1B shows an enlarged detail view of FIG. 1A showing an electromagnet. FIG. It shows the position during displacement of the plate relative to the core at the moment when the potential difference is applied to the coil. Said displacement may be defined as a “piston stroke”. When the piston stroke fluctuates, the inductance value of the electromagnet changes. It shows the position during displacement of the plate relative to the core at the moment when the potential difference is applied to the coil. Said displacement may be defined as a “piston stroke”. When the piston stroke fluctuates, the inductance value of the electromagnet changes. It shows the position during displacement of the plate relative to the core at the moment when the potential difference is applied to the coil. Said displacement may be defined as a “piston stroke”. When the piston stroke fluctuates, the inductance value of the electromagnet changes. It shows the position during displacement of the plate relative to the core at the moment when the potential difference is applied to the coil. Said displacement may be defined as a “piston stroke”. When the piston stroke fluctuates, the inductance value of the electromagnet changes.

  The present invention will be better understood from the following detailed description and reference to the accompanying drawings, which illustrate preferred embodiments of the invention by way of non-limiting example only.

  The metering pump according to the present invention is basically constituted by three basic members, that is, an electronic card, an electromagnet, and a pump body.

  The core of the system is an electromagnet. The electromagnet is appropriately managed by the electronic card and drives the piston pulled back by the spring, preferably in a pulse mode ranging from 0 to 360 pulses / minute.

  The inventive idea underlying the present invention is to drive the electromagnet while gradually increasing the voltage while at the same time the electronic system is directly related to the position of the piston at the maximum possible stroke. In order to obtain a corresponding value of impedance, the current flowing through the solenoid is to be measured. With the potentiometric or digital adjustment that can be set directly by the operator via the electronic card interface, it is possible to select the exact stopping point of the piston, ie its maximum stroke, with a precision of 1/100. it can. As a result, the described pumps provide very high accuracy for the amount of additive injected by each single drive of the electromagnet without the need for specific mechanical adjustments or additional sensors and electronic feedback that are costly. Can be changed.

  For the operation of the metering pump described, the moving part of the electromagnet 1 (referred to as “plate” 2) is displaced until it approaches the magnetic flux present in the core of the electromagnet, and thereby the piston 3 fixed to the plate 2. It is thought that the displacement of is caused. As already mentioned, the displacement is defined as a “stroke”.

  From an electrical point of view, the electromagnet is nothing but an inductor constituted by a winding (having a predetermined geometric shape) housed in a ferromagnetic material. In this case, there is a gap that tends to close according to the displacement of the plate 2.

  The gap is a distance (L1, L2, L3, L4) between the fixed portion and the movable portion of the electromagnet. This distance coincides with the “stroke”. At the same time as the movable part (plate fixed to the piston) is displaced, the mechanical characteristics of the inductor itself fluctuate. In particular, the physical parameter defined as literally “magnetoresistance” fluctuates, so the inductance value fluctuates. To do.

  In view of the above, it is possible to accurately determine the relationship between the displacement of the plate 2, and thus the displacement of the piston 3, and the variation in inductance as a function of said displacement. The reason for this can be that the relevant quantities can be reduced to those typical for inductors, i.e. the number of turns in the winding, the cross section of the core, the length of the air gap, etc. and can therefore be calculated mathematically. Because.

  For this reason, the present invention measures the inductance of the electromagnet 1 (thus measuring the physical parameters determined solely by the product geometry and the structural parameters unaffected by any type of drift) and the piston. This is based on the possibility of relating 3 displacements.

  It is known that the impedance of an electromagnet is characterized by the resistance coefficient typical of the copper that makes up the winding, the induction coefficient resulting from the number of turns, and the geometry of the iron itself.

  The operation of the instrument is a measurement of the impedance Z = V / I of the electromagnet at a constant voltage (V = constant) and the duration of a typical pulse supplied to the electromagnet configured to obtain, for example, a 1 millimeter stroke. Characterized by measurement of instantaneous current (I) every millisecond for a predetermined maximum time equal to time, eg 100 ms. In this way, 100 values of instantaneous impedance corresponding to the displacement are obtained, and as a result, one hundredth of the measurement is performed.

For what has already been described, the equation representing the gradual variation of the current in the impedance referred to at the above point (which can represent an equivalent electrical circuit of the electromagnet) is as follows:
i (t) = (V / R) * [1-e- ^{(R / L) t} ]
in this case,
R is the pure resistance of the armature,
L is the inductance of the electromagnet (changes with time according to the displacement of the plate),
V is a constant voltage applied,
e is the number of Napiers and is equivalent to 2.6182.

  The resistance R remains practically constant except for minor variations as a function of temperature that can be corrected in all cases. If it is desired to adjust the stroke with very high accuracy, it is sufficient to insert a temperature sensor in order to correct the value of the resistance R of the electromagnet 1 and to measure the impedance of the electromagnet 1 more accurately.

  In this way, it can be seen that the variation of the inductance L changes the gradual variation of the current and is mathematically related to the geometric structure of the electromagnet 1. For this reason, it is possible to characterize this by simply sampling the current of each electromagnet at a constant voltage and measuring the impedance of each electromagnet only once at the first energization. Repeated for all operating conditions. Thereby, the displacement of the piston 3 and the plate 2 fixed to the piston 3 is shown for the reason mentioned above.

  According to the present invention, the impedance measurement is performed as long as the force applied to the electromagnet 1 is determined by the stroke to be performed by the piston that determines the amount of liquid to be injected, not by the back pressure of the system. It is not affected by the pressure of the connected system, nor is it affected by the pressure fluctuation.

  By measuring the impedance instantaneously, it is also possible to block the plate at a specific position in its stroke or maintain a long pulse of displacement to facilitate the outflow of the delivered liquid This increases hydraulic efficiency, especially when viscous liquids are processed.

  Thus, each electromagnet is characterized by its own table of impedance values correlated with strokes and managed by a microcontroller.

  According to a characteristic characteristic of the present invention, the electromagnet 1 is connected to an electronic microcontroller card. The electronic microcontroller card detects in real time the position of the piston 3 as a function of the variation of the impedance value of the electromagnet 1 and thereby adjusts the stroke of the piston 3 as required, so that the pump Is designed to regulate the amount of liquid injected instantaneously. The greater the stroke of the piston 3, the greater the capacity of the metering pump.

  While the piston 3 fixed to the plate 2 is moving, the impedance of the electromagnet 1 varies. This is because the magnetic resistance of the magnetic circuit of the electromagnet fluctuates corresponding to the variation of the stroke, and therefore the inductance of the electromagnet fluctuates. From this, according to the present invention, as described above, it can be inferred that the stroke is controlled by controlling the impedance.

  In the example of the embodiment described purely for illustration purposes, when the instrument is first activated in a factory test process, the electronic circuit supplies the first pulse, which causes the piston 3 to perform its full stroke. Thus, by measuring the current and voltage of the electromagnet 1 at 1 millisecond intervals, the corresponding internal inductance value is stored in its own internal memory along with the actual value of the piston stroke.

  If the inductance is a variable amount, only if some amount of physical and mechanical properties that can determine minor variations in stroke are variable, then the pump will be in the life cycle of the pump itself. Clearly, further calibration to be performed is necessary.

  In this case, the microcontroller receives, as an external input, the desired position of the piston stroke, related to the exact capacity of the metering pump, and supplies a series of pulses so that an intermittent magnetic field can be generated. Thus, the power supply circuit connected to the electromagnet is managed. Such a magnetic field attracts or releases the plate 2. The plate 2 is fixed to the piston 3, and the piston 3 is similarly fixed to the diaphragm 4. The plate 2 displaces the diaphragm 4 in the pump body 5, and as a result, the liquid agent is sent out toward the aqueous solution.

  Each time during the displacement of the piston, and thus the displacement of the plate, the impedance of the electromagnet fluctuates step by step, and by detecting this, the stroke to be performed is determined. This gives the device microcontroller the possibility to identify the stop point of the piston itself.

  When the pump is reset, the electronics will allow an acceptable level of atmospheric temperature that is expected to properly operate the metering pump, so that the pump capacity can meet the required needs, for example. The current as a function of the request.

  In this way, it is advantageously avoided that more energy is consumed than is necessary for the work required for the metering pump. Also, the level of performance does not change over time and continues to have a beneficial effect on metering and equipment life.

  The metering pump comprising the control device may likewise be connected via a serial port with a remote computer that allows intervention in the operation of the pump itself.

  The first advantage of using the device described so far is that the piston stroke 3 as a function of the work that the metering pump has to do effectively and thus as a function of the amount of liquid that the metering pump must inject. Indicated by being able to adjust. This not only saves from an energy point of view (limited to the level that is effectively needed for the job), but accurate metering that is constant over time prevents waste of additive liquids. This implies that it also saves the user from an economic point of view.

  A second advantage is that the position of the piston 3 during the stroke can be known with an accuracy of the order of 1 / 100th of a millimeter via the electronic control card.

  A third advantage is indicated by the fact that the piston stroke 3 can be set during programming of the microcontroller. This results in a further double advantage, namely the omission of the mechanical calibration means necessary for the proper definition of the piston stroke and the economic savings due to said omission. Metering pumps with different technical characteristics can be produced using the same product configuration.

  A further advantage of the present invention is that the metering pump with the electromagnet described so far works at a temperature lower than the temperature at which the conventional metering pump does work, thereby preventing excessive heating. . This is due to the fact that, depending on the mechanical means, the piston stroke is not limited without reducing the energy applied to the electromagnet, but the piston stroke is limited only by limiting the energy. come.

A further advantage of metering pumps stems from the possibility of realizing the following two functions that are suitable for new systems.
1. “Underload”: detection of the absence of liquid or additive in the pump body during normal operation of the device,
2. “OVERLOAD”: Detection of possible blockages or excessive pressure in the pump supply line during normal operation of the device.

  The situation (underload and overload) can be detected by allowing the electronic device to evaluate both the position of the piston and the speed of its displacement.

  In the event of an underload, the absence of liquid or additive in the pump body greatly increases the speed of piston displacement, and the microcontroller detects the situation by controlling inductance variations in real time. A warning signal is transmitted immediately or after a predetermined number of pulses, based on the settings entered in the programming step. In case of underload, the system can consider a re-injection procedure that initiates a supply that provides a predetermined number of infusions during a programmed and clear period.

  The overload function allows the electronic device microcontroller to detect the lack of metering, with or without a known type of suitable external device (flow sensor). Blockage of the pump supply line, whether partial or total, slows the piston displacement. How late is determined as a function of the degree of occlusion. The electronic circuit of the pump obtains the data and sets its state to the alert state after a predetermined period of time, thereby indicating an overload state.

  No. 1343207, filed in the name of the Applicant, named “POMPA DOSATRICE DOTATA DI MEZZI DI AUTOREGOLIONE DELLA POTENZA ASORBITA” (“metering pump with means for self-adjusting absorbed power”) It should be noted that a metering pump is described which controls the piston stroke by means of a switch and stops the energy supply to the coil in the vicinity of the end of the stroke, thereby eliminating wasteful waste of energy.

  Furthermore, the patent application RM2009A000537 entitled “DISPOSITIVO DI CONTROLLO DELLA CORSA DEL PISTONE DI UNA POMPA DOSATRICE” (“device for controlling the stroke of the piston of a metering pump”) filed in Italy by the applicant. The document does not simply control the stroke end of the piston, but it adds the metered dose by verifying the position of the piston instantaneously based on the distance between the plates of the capacitor and controlling with an electronic card. A metering pump is described comprising a capacitive sensor connected to an electromagnet that defines and determines the exact amount of liquid.

  Unlike these technical solutions just mentioned, the present invention lays the basis for controlling the position of the piston 3 in measuring the inductance of the electromagnet 1. In this way, the stroke end switch and the capacitance sensor are omitted.

  In other words, in addition to performing the function of the pump actuator, the electromagnet 1 also functions as an inductive sensor that detects and manages the position of the piston 3, and thus the capacity of the pump.

  Finally, it is known that other procedures for electronic metering pumps were trying to achieve the same goal by controlling the current through the electromagnet. However, the results obtained did not achieve proper and sufficient pump operation.

  Although the present invention has been described and illustrated in connection with a preferred embodiment, those skilled in the art may modify and / or modify this preferred embodiment without departing from the scope of protection of this industrial patent. Obviously, it can be changed. For example, for electromagnets, a suitably sized winding and a core with various geometries can be considered, and the dispersion of the magnetic field is minimized with a beneficial effect on efficiency and reduced heat loss. You can think of a solution.

1. Electromagnet Plate 3. Piston 4. Diaphragm 5. Pump body

Claims (14)

  In the device for controlling the stroke of the piston (3) of the metering pump and comprising an electromagnet (1), the pump part is configured to measure and measure the electromagnet (1) such that the pump member is an actuator as well as a sensor. For this purpose, the electromagnet (1) comprises a fixed plate and a movable plate (2) fixed to the piston (3), in this case each displacement of the piston Different distances between the plates, and thus different values of the impedance of the electromagnet itself, correspond, and the electromagnet is connected to a microcontroller electronic card, which is subject to inductance variations Due to the variation of the value of impedance of the electromagnet caused, the piston (3 The device is designed to detect the position of the magnet in real time, the inductance variation being determined only by the geometric / structural characteristics of the electromagnet (1) and not by the functional or environmental parameters .   An intermittent magnetic field that attracts and releases the plate (2) to program the microcontroller to correlate each variation in inductance of the electromagnet with the piston stroke and thus the various capacities of the metering pump. Is applied to the electromagnet (1), the plate (2) is fixed to the piston (3), and the piston (3) is further connected to the diaphragm (4). The plate (2) displaces the diaphragm (4) in the pump body (5), so that the drug is delivered to the system to which the pump is attached, thereby An accurate piston stroke is associated with each inductance value detected by the microcontroller. Are, the exact value of the piston stroke, characterized in that it is stored in the memory of the microcontroller itself, according to claim 1.   In order to keep the capacity of the metering pump constant, the electronic card sends a pulse to measure the inductance at the first start-up of the pump itself, so that the piston stroke and the electromagnet inductance itself Are associated with each other, and the first pulse is designed to cause the piston (3) to make a full stroke, in which case the microcontroller causes the current of the electromagnet (1) to be 1 millisecond. The device according to claim 1, characterized in that it can be measured at intervals and stores the value together with the piston stroke in its own internal memory and at the same time obtaining the inductance of the electromagnet.   The microcontroller maintains a constant impact current to the electromagnet based on a comparison between an inductance value included in the internal memory of the microcontroller and associated with the piston stroke and a detected value of the inductance. Device according to claim 1, characterized in that it is designed to adjust the piston stroke (3) by adjusting to a frequency of.   The microcontroller is designed to adjust the piston stroke (3) by adjusting the current required for the electromagnet (1) to displace the piston (3). The apparatus according to claim 1.   In order for the microcontroller to detect an underload condition, i.e. to detect the absence of additive liquid in the pump body during normal operation of the device, the speed of displacement of the piston (3) is adjusted. Device according to claim 1, characterized in that it is designed to be verified and evaluated.   In order for the electronic device to detect an overload condition, i.e. to detect possible blockages or excessive pressure in the pump supply line during normal operation of the device, the piston (3) The device according to claim 1, wherein the device is designed to verify and evaluate the speed of displacement.   A metering pump comprising a device for controlling the piston stroke (3) according to any one of the preceding claims.   A serial port for connecting a computer or other similar electronic device for remote acquisition of information collected by the microcontroller and / or intervention in the operation of the pump itself The metering pump according to claim 8.   2. The device according to claim 1, wherein the control device is able to determine the arrival point of the plate (2) and therefore the end of the stroke, even though it is envisaged to measure the current using the impedance for calculation. However, the microcontroller electronic card sets the relationship between the value of the inductance and the position taken by the piston (3) during the stroke and is based on the settings made by the user. , Designed to determine at which position the piston stroke is blocked, thereby allowing the piston stroke (3) to be controlled with an accuracy of 1/100, thus each 1 of the additive liquid A device characterized by the possibility to control the pump capacity for a single injection.   The microcontroller electronic card controls the current to the electromagnet (1) to prevent any wasted energy, and drives the solenoid of the electromagnet (1) with the correct amount of current; Control the advance through the calculation of the impedance and determine its interruption at a precisely defined position that can be set by calibration of the electronic circuit without any mechanical system to control the pump capacity The apparatus according to claim 1, wherein:   In order to control the piston stroke (3) so as to instantaneously change the injection amount of the metering pump, it is determined whether or not the microcontroller electronic card has reached a predetermined stroke end, and in real time Control what happens to the electromagnet (1), calculate the impedance, determine the exact point where the piston stroke (3) should stop, and the solenoid of the electromagnet (1) performs the function of an actuator In addition, the device according to claim 1, wherein the device is also realized to function as a sensor.   Basically, it is constituted by a pump body having three basic members: an electronic card, an electromagnet (1), and a piston (3), the electromagnet (1) being appropriately driven by the electronic card, 10. Metering pump according to claim 8 or 9, characterized in that the electromagnet (1) drives the piston (3) pulled back by a spring, preferably in a pulse mode in the range of 0 to 360 pulses / min.   The electronic card drives the electromagnet (1) while gradually increasing the voltage, while at the same time the electronic card is directly related to the position of the piston (3) at the maximum possible stroke. To obtain a corresponding value of 1/100, by measuring the current through the solenoid of the electromagnet and by potentiometric or digital adjustment that can be set directly by the operator via the interface of the electronic card. With accuracy, select the exact stopping point of the piston, i.e. its maximum stroke, so that each of the electromagnets without the aid of costly specific mechanical adjustments or additional sensors and electronic feedback. It is possible to change the amount of additive liquid injected by one driving with extremely high accuracy. Metering pump according to claim 13, wherein the door.