FIELD OF THE INVENTION

Embodiments of the present invention concern a method to define the precise and accurate delivery of predefined quantities of fluid into containers in relation to a filling device comprising a peristaltic pump.

The present invention also concerns a filling device using said method to use and control the delivery in succession of precise and accurate quantities of fluid to fill containers.

The filling device according to the present invention is applied particularly, but not restrictively, in the pharmaceutical or health sector, and in any case in any condition where defined and controlled quantities of fluid products are to be delivered, advantageously in succession, into suitable containers, even of minimum values.

BACKGROUND OF THE INVENTION

Some applications that adopt peristaltic pumps, in relation to the type of fluid that they treat and its precise destination, have the necessity to deliver, precisely and accurately, at times very accurately, defined quantities of fluid.

Some applications provide continuous delivery for the administration of medicines in liquid form to a patient.

For example, document US-A-2015/0037168 (US' 168) describes a deliverer for the continuous delivery of a constant flow of liquid medicines which is provided with a mono-roller peristaltic pump in which there is a flexible tube with an adjacent segment of its entrance and exit ends.

Therefore, this solution is intended to manage the delivery of a limited quantity of a medicine in a patient with a constant flow.

However, in the production of pharmaceutical, chemical, health, or other products for which a high degree of precision is required in the successive filling of suitable containers with predefined quantities of fluid, even small quantities, this solution is not suitable to obtain precise deliveries in succession. In fact, the deliverer described in US Ί 68 is not intended to obtain the precise repeatability of deliveries in succession that is required in the context of filling containers. US' 168 does not suggest any way of using the deliverer which can allow to obtain a plurality of precise deliveries in succession, considering the specific problems related to the adjacent segment and the drive and stop transients of the peristaltic pump.

The deliverer described in US' 168 provides to increase the rotation speed of the roller when it acts on the adjacent segment, since in some specific conditions, that is, far from the transients, the increase in the rotation speed of the roller allows to continuously deliver a quantity of medicine with a constant flow.

The solution described in document US' 168 is ineffective for small deliveries, or in any case during the roller start-up phase.

Applying the known solution described in US' 168, there is no effect on the trend of the quantity delivered by small rotations of the roller, or during the startup of the latter. This means that this known solution is inadequate for filling containers with quantities delivered discretely with repeated starts and stops of the roller, especially if the roller is started in the adjacent segment. Therefore, the solution of US' 168 does not allow to fill in succession and in a precise manner containers with desired quantities of liquid, since it is affected both by the different volumes of liquid displaced in the adjacent segment, and also by the non-controllable deliveries of liquid when the roller is driven, that is, during the starting and stopping transient of the roller.

In the sector of the successive filling of containers with liquid products, normally the deliveries are repeated continuously at desired or conditioned intervals.

This is all the more urgent in the case of liquids used in the production of pharmaceutical, chemical, health, or other products for which a high degree of precision of the components delivered is required, and in which even thousands of doses are produced at very high production rates.

Known peristaltic pumps normally have a flexible tube inserted into a cylindrical containing structure, containing a pressing element, normally planetary rollers, rotating around the same axis. The axis is central to the cylindrical containing structure, and the pressing element, rotating on its own axis, presses against a flexible tube disposed on at least part of the internal perimeter of the cylindrical containing structure, and inside which there is the fluid to be delivered. The entrance and exit of the flexible tube from the cylindrical containing structure normally conform to a U-shaped disposition. For example, the prior art documents US-A-2005/0047925 and US-A-2015/0013825 describe two peristaltic pumps having a U-shaped flexible tube with a plurality of planetary rollers.

In such known peristaltic pumps, the progressive and continuous compression action exerted by the pressing element on the flexible tube during its rotation, displaces the fluid continuously and in a defined quantity from the entrance end to the delivery end.

It is known that peristaltic pumps require frequent maintenance because, as the result of the multiple compressions exerted by the planetary rollers on the flexible tube, the latter tends on the one hand to wear, and on the other hand it tends to age before time on the pressing side, and can even deform and/or be irreversibly damaged.

Known peristaltic pumps also exist in which the flexible tube, is shaped like a "γ" (Greek letter gamma), instead of being U-shaped. In this conformation, the flexible tube has an adjacent segment in which portions of the entrance and exit extensions are located substantially adjacent and opposite one another.

The peristaltic pump described in US '825 requires that the rollers are repositioned in the initial position on each occasion and with each delivery, in order to obtain the initial configuration of the peristaltic pump, so that the latter can deliver, with every repetition, the desired quantity of fluid starting from the same initial configuration.

This entails, however, the presence of a three-way valve, which not only makes the system more complex, but is also the source of other problems of maintenance and stagnation of liquid along the tubes connected to it.

Known peristaltic pumps have the pressing element that can consist of a roller, two opposite rollers, an orbital lobe, etc.

Known peristaltic pumps, if used for functions of transferring fluids that have to be controlled at least in volume, create many difficulties with regard to an accurate control.

In fact, in the adjacent segment, the pressing element works simultaneously, and sometimes not uniformly, on both extensions of the flexible tube, where the pressing element also acts in the adjacent segment of the flexible tube with entrance and exit transients that are not uniform and do not correspond to the characteristics of the remaining part of the flexible tube.

This behavior makes it difficult to have an accurate and desired control of the quantity of fluid delivered, when the quantity delivered requires that the pressing element transits wholly or partly along the adjacent segment.

In fact, in the case of repeated delivery, the pressing element temporarily stops at any angular position whatsoever, also randomly, where the peristaltic pump has to be able to deliver quantities of fluid in sequence, but not uniform.

There is therefore a need to perfect and make available a method to use and control a filling device that overcomes at least one of the disadvantages of the state of the art.

The purpose of the present invention is to obtain a method to use and control a filling device comprising a peristaltic pump in which there is an adjacent segment of the entrance and the exit extensions of the tube, and in which an accurate control is required of the quantity delivered, said quantity being repeated and able to vary over time, or with precise frequencies.

The method allows to deliver precise and accurate quantities of fluid, even minimal, ensuring the constancy of the volume of fluid delivered both over time and also during the transient when the pressing element is acting on the adjacent segment.

Another purpose of the present invention is to provide a filling device that uses the control method to deliver defined and precise quantities of fluid, also for filling containers in succession.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

In accordance with the above purpose, the present invention concerns a method to use and control a device for filling containers with predefined quantities of fluid delivered discretely into each container by means of a peristaltic pump selectively activated to perform a cycle of filling a container.

The peristaltic pump can comprise a containing structure with a cylindrical chamber in which a flexible tube is circumferentially disposed, provided with an entrance extension connectable to a power source and with an exit extension with an exit for the delivery of the fluid.

The flexible tube has a circumferential segment that defines an adjacent segment of at least part of the entrance extension with the exit extension.

The peristaltic pump can comprise a single rotating roller able to progressively compress the flexible tube for a desired angle value, along a circumferential path, in order to convey discretely predefined quantities of the fluid.

By the term discretely we mean that the peristaltic pump is selectively started and stopped for each container to be filled with the desired quantity.

The flexible tube has an adjacent segment of at least part of its entrance and exit extensions, and is configured as a gamma shape "γ".

The flexible tube is functionally associated with a pressing element able to progressively and continuously compress the flexible tube for the desired circumferential path determined by the expected flow rate, in order to transfer a defined and precise quantity of fluid from the entrance end to the delivery end of the flexible tube itself.

According to possible embodiments of the use of this peristaltic pump, the pressing element can deliver the required quantity of fluid, passing through a portion of the flexible tube, or one or more circuits of the flexible tube, even incomplete ones and/or a part of the adjacent segment.

In accordance with one aspect of the present invention, the use and control method provides:

- to define sectors of the flexible tube, including the adjacent segment, relating to the circumferential path and depending on their circumferential position, said sectors being identified sequentially by angular segments;

- to determine the initial angular position of the rotating roller;

- to determine the volume of the fluid contained in the individual sectors defined between the initial contact of the rotating roller and the exit of the exit extension;

- to record, for every predefined quantity of fluid to be delivered, the circumferential starting and stopping position of the rotating roller, wherein the predefined quantity to be delivered into each container corresponds to the sum of the volumes contained in a number of sectors and/or in angular portions of the latter, affected by the rotating roller;

- to selectively activate the rotating roller to deliver in succession the predefined quantity of fluid into the containers in relation to the circumferential starting position of the rotating roller;

- to detect the instantaneous quantity of fluid progressively delivered by the action of the rotating roller;

- to control the quantity of fluid delivered into each container, comparing the instantaneous quantity with the predefined quantity to be delivered in order to deactivate the rotating roller when the predefined quantity to be delivered is reached.

Because the angular starting position of the rotating roller and the volumes of fluid contained in the specific individual sectors are known, it is possible to deliver precise quantities of fluid into suitable containers in succession.

This aspect achieves an efficient and continuous control of the quantity actually delivered by the peristaltic pump, which allows to manage the functioning of the latter until the volume to be delivered into each container is reached.

According to possible embodiments, the detection can be carried out by a sensor, such as a weight sensor, a level sensor, a presence sensor, or other sensor suitable to detect the instantaneous quantity of fluid delivered.

According to possible embodiments, the use and control method can provide to process the total volume of the fluid to be delivered in relation to the starting position of the rotating roller and to command the rotating roller along the circumferential path defined between the starting and stopping positions of the rotating roller corresponding to the specific total volume of the fluid to be delivered.

According to possible embodiments, the sectors can be uniform, or differentiated, and can also be sized according to the minimum tolerance admitted both in relation to the quantity of fluid to be delivered and in absolute terms. According to possible embodiments, the use and control method allows to deliver quantities of fluid also considering portions of sector in relation to the volume of fluid to be completed.

According to possible embodiments, the method can provide to drive the rotating roller by a movement member subjected to a control and command unit in order to define, on each occasion, the specific angular position of the rotating roller.

According to possible embodiments, the angular speed of the rotating roller can be constant.

According to possible embodiments, the angular speed of the rotating roller can be variable continuously or between one delivery and the next.

According to possible embodiments, the determination of the volumes can be obtained by applying a functional relation that combines one or more chemical- physical characteristics of the fluid chosen from a group comprising viscosity, response to compression, the properties of adhesion to a surface and the sliding properties inside the flexible tube, with one or more structural characteristics of the peristaltic pump chosen from a group comprising the response to the compression of the flexible tube, its disposition in the cylindrical chamber, the thickness of its walls, and the diameter of the channel where the fluid passes. According to possible formulations, the present invention concerns a filling device of a peristaltic pump to fill containers with predefined quantities of fluid delivered discretely into each container, comprising a peristaltic pump selectively activated to perform a cycle of filling a container.

The peristaltic pump can comprise a containing structure with a cylindrical chamber in which a flexible tube is circumferentially disposed, provided with an entrance extension connectable to a power source, and with an exit extension with an exit for the delivery of the fluid, wherein the flexible tube has a circumferential segment that defines an adjacent segment of at least part of the entrance extension with the exit extension, said peristaltic pump comprising a single rotating roller able to progressively compress the flexible tube for a desired angle value, along a circumferential path, in order to convey discretely predefined quantities of fluid.

In accordance with one aspect of the present invention, the filling device comprises:

- a detection element to determine the angular position of the rotating roller;

- a processing unit configured to determine the volumes of fluid contained in sectors defined sequentially by angular segments of the flexible tube, including the adjacent segment, between the initial contact of the rotating roller and the exit of the exit extension;

- a memorization unit configured to record, for every predefined quantity of fluid to be delivered, the circumferential starting and stopping position of the rotating roller, wherein the predefined quantity to be delivered into each container corresponds to the sum of the volumes contained in a number of sectors and/or in angular portions of the latter, affected by the rotating roller;

- at least one sensor to detect the instantaneous quantity of the fluid delivered;

- a control and command unit configured to selectively activate the rotating roller to deliver in succession the predefined quantity of fluid into the containers in relation to the circumferential starting position of the rotating roller; the control and command unit being configured to control the quantity of fluid delivered into each container, comparing the instantaneous quantity detected by the sensor with the predefined quantity to be delivered in order to deactivate the rotating roller when the predefined quantity to be delivered is reached.

According to possible embodiments, the sensor can be a weight sensor, such as a load cell for example.

According to possible embodiments, since the starting position of the rotating roller and the volume of fluid to be delivered are known, the control and command unit can be configured to determine the circumferential path defined between the starting and stopping positions of the rotating roller corresponding to the specific total volume of fluid to be delivered.

According to possible embodiments, the rotating roller can be configured to proceed at a constant angular speed.

According to possible embodiments, the rotating roller can be configured to proceed at an angular speed that is variable continuously or between one delivery and the next.

The control and command unit is intended to command the pressing element in relation to its position in a coordinated manner with its defined and accurate volumes to be delivered on each occasion.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 schematically shows a peristaltic pump according to a possible embodiment of the present invention;

- figs. 2-3 show a detail of fig. 1 with a pressing element operating in the initial and final position of the adjacent segment of the flexible tube;

- fig. 4 shows figs. 2 and 3 overlapping with the sectors of the adjacent segment.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can conveniently be incorporated into other embodiments without other clarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

Embodiments of the present invention concern a method to control a peristaltic pump 10 configured to deliver a desired quantity of a fluid 1 1 in a precise, accurate and controlled manner.

It should be noted that the present invention allows controlled delivery of fluid 1 1 of any nature, even comprising different substances, and having various chemical-physical characteristics.

It should be considered that fluid 11 refers, by way of example, to any fluid whose chemical-physical characteristics are known in relation to the specific needs of its use.

By way of non-restrictive example, the chemical-physical characteristics can be viscosity, response to compression, the properties of adhesion to a surface, or other properties related to the flow of the fluid inside a flexible tube.

Particularly considered are pharmaceutical or health products in liquid or semi-liquid form, which have to be delivered on each occasion in a defined and precise quantity with margins of tolerance that can also be very limited. The delivery can be defined on each occasion, or repeated for a defined or definable number of times.

Possible embodiments described using fig. 1 concern a filling device 100 for containers with predefined quantities of fluid 1 1 discretely delivered into each container comprising a peristaltic pump 10 which can be selectively activated to carry out a filling cycle of a container.

The peristaltic pump 10 comprises a containing structure 12, having a cylindrical chamber 13 in which a flexible tube 14 is circumferentially disposed. The flexible tube 14 is connected on one side to a power source 15 and, on the other, to the delivery user device 16.

According to possible embodiments, the containing structure 12 can comprise, in relation to the openings where the flexible tube 14 enters and exits, suitable connections 17 configured to fluidically connect the flexible tube 14 to the power source 15 and/or to the delivery user device 16 through possible tubes or connection means 18.

By way of non-restrictive example, the power source 15 can comprise a deliverer, a container, or another type of source of fluid 1 1 provided with an opening 28 fluidically connected to the peristaltic pump 10.

The delivery user device 16 can comprise, by way of example, a deliverer of fluid 1 1 or other similar element able to continuously and/or sequentially deliver one or more desired quantities of fluid 1 1 into a container, or other.

The flexible tube 14 can have an internal diameter of any normal but known value, just as the characteristics of the constituent material are known. The flexible tube 14 is configured to convey a fluid 11 and has a circumferential segment 29 closed in a ring, obtaining an adjacent segment 19 of at least part of its entrance extension 20 with its exit extension 21.

The flexible tube 14 is functionally associated with a pressing element 22 which acts progressively and continuously compressing the flexible tube 14 by a desired angle value, along a circumferential path, determined by the expected flow rate, in order to transfer a defined and precise quantity of fluid 1 1 from the input end 23 to the delivery end 24 of the flexible tube 14 itself.

In the example shown, the pressing element 22 is a roller suitable for the purpose.

According to possible embodiments, the pressing element 22 can therefore comprise a single rotating roller.

According to other embodiments, the pressing element 22 can comprise a plurality of rotating rollers, or an orbital lobe, or other.

According to possible embodiments, the pressing element 22 is driven by a motor member (not shown) which acts on a movement member 25, which is configured to allow the pressing element 22 to operate in a controlled manner along the circumferential section 29. The movement member 25 is subjected to a control and command unit 27 to define on each occasion the specific angular position and therefore the circumferential path of the pressing element 22.

The rotary movement of the pressing element 22 is controlled angularly by the control and command unit 27 associated with an encoder system, or analogous system which makes it possible to accurately recognize the angular position of the pressing element 22 also in the transient when it operates in the adjacent segment 19.

According to possible embodiments, in the case where the pressing element 22 consists of a single roller, it will rotate around the axis of rotation 30 of the cylindrical chamber 13 of the containing structure 12.

The flexible tube 14 is progressively and continuously compressed by the pressing element 22, so that the flexible tube 14 is gradually and continuously squeezed, causing the fluid 11 to advance downstream and aspirating the fluid 1 1 upstream.

The pressing element 22 can deliver the quantity of fluid 1 1 required by passing through a portion of flexible tube 14, or one or more circuits thereof, also not complete and/or a part of the adjacent segment 19.

It is obvious that when the pressing element 22 cooperates with the adjacent segment 19 of the flexible tube 14, the quantity of fluid 1 1 changes and is no longer controllable correctly with the desired precision.

The problem therefore arises of obtaining a precise control of the delivery even when the pressing element 22 cooperates with part, or all, of the extension of the adjacent segment 19.

However, it must be remembered that the quantity changes already just before the pressing element 22 comes into direct correlation with the adjacent segment 19, due to the typical behavior of the flexible tube 14 which is progressively squeezed.

The inventive idea therefore provides to identify the starting point and the end point of the perturbation created by the pressing element 22 on the adjacent segment 19 of the flexible tube 14.

Since the perturbation in the delivery of the pressing element 22 in the segment of flexible tube 14 traveled and/or in the adjacent segment 19 is known, it is possible to divide the flexible tube 14 into defined segments Si, including the adjacent segment 19.

The sectors Si will be correlated to the degree of precision required in the flow of fluid 1 1.

The sectors Si can be uniform, or differentiated, according to operational needs. The sectors Si can be sized according to the minimum tolerance allowed in relation to the quantity of fluid 1 1 to be delivered.

Since the subdivision of the transient and the circumferential position at the beginning of delivery and the position at the end of delivery of the pressing element 22 are known, the quantity of fluid 11 delivered can be precisely defined. According to possible embodiments, this definition can be theoretical and/or practical.

According to a possible embodiment, the use and control method for a filling device 100 can provide to:

- define sectors Si relating to the circumferential path which are uniform or differentiated according to their circumferential position, said sectors Si being sequentially identified by angular segments;

- determine the precise volume Vi of the fluid contained in each of the individual sectors Si in relation to the specific circumferential position and relating to the flexible tube 14;

- qualify and position circumferentially the sectors Si defined between the initial contact of the pressing element 22 with the adjacent segment 19 of the flexible tube 14 and the corresponding end outlet;

- memorize the angular starting position of the pressing element 22;

- record for each total volume of fluid 1 1 to be delivered the circumferential starting and stopping position of the pressing element 22;

- process the individual volumes Vi of the fluid 1 1 in the precise individual sectors Si in relation to their position with respect to the circumferential position and in relation to the circumferential path of the pressing element 22. The index i refers to the i-th sector (SI, S2, S3, ...) where the i-th volume (VI, V2, V3, ...) is contained.

According to possible embodiments, the use and control method can provide to continuously detect the volume of fluid 11 relating to the sum of the volumes Vi of the sectors Si progressively affected by the pressing element 22, to compare the total volume of fluid 11 displaced on each occasion with the volume of fluid 1 1 to be delivered, and to command the pressing element 22 to stop when the defined and precise volume of fluid to be delivered is reached.

According to possible embodiments, the use and control method can provide to process the total volume of fluid 11 to be delivered in relation to the starting position of the pressing element 22 and to command the pressing element 22 along a precise circumferential path defined according to the starting position and therefore according to the defined and precise volume of fluid to be delivered.

It is obvious that the detection of the quantity of fluid 11 delivered can be performed before or in correspondence with the delivery end 24 using appropriate sensors and devices suitable for this purpose.

According to possible embodiments, the use and control method allows to deliver quantities of fluid 1 1 also from portions of sectors Si as a function of the volume of fluid 1 1 contained in the portion of sector Si.

According to possible embodiments, the pressing element 22 can deliver the required quantity of fluid 1 1 along at least a portion of the circumferential path.

According to possible embodiments, the plurality of sectors Si can be determined in relation to the flexible tube 14 and to the circumferential path explored on each occasion by the pressing element 22. The path can possibly comprise the adjacent portion 19 of the flexible tube 14, in which the flow rate of the fluid 11 at exit varies if not suitably controlled.

For example, if the adjacent segment 19 is defined according to the angular position of the pressing element 22 with respect to the center of rotation 30 in the cylindrical chamber 13, the sectors Si can be defined as angular sectors explored by the pressing element 22.

The determination of the volumes Vi of fluid 11 is obtained by applying a functional relation which, based on the chemical-physical characteristics of the fluid 1 1 and the structural characteristics of the peristaltic pump 10, that is, the characteristics of the flexible tube 14 and of how it is disposed in the cylindrical chamber 13, allows to precisely determine the quantity of fluid 1 1 contained in the individual sectors Si of the adjacent segment 19.

The functional relation combines one or more chemical-physical characteristics of the fluid 11 chosen from a group comprising viscosity, response to compression, properties of adhesion to a surface, and the sliding properties inside the flexible tube 14; with one or more structural characteristics of the peristaltic pump 10 chosen from a group comprising the response to compression of the flexible tube 14, the disposition of the flexible tube 14 in the cylindrical chamber 13, the thickness of the walls of the flexible tube 14, and the diameter of the channel 26 of the flexible tube 14.

The position of the pressing element 22 can be detected for example by means of a detection element 31 , such as for example an encoder associated therewith, for example, on the axis of rotation 30 of the movement member 25. The encoder can be comprised in the control and command unit 27.

By processing the volumes Vi of fluid 1 1 with the instantaneous position of the pressing element 22, it is possible to command the pressing element 22 in a controlled and precise manner by means of the movement member 25, so as to deliver the desired quantity of fluid 1 1.

Since the volumes Vi of fluid 1 1 in the individual sectors Si of the adjacent segment 19 are known, it is possible to compensate for the variation in the flow rate of the fluid 1 1 at exit determined in the transient in which the pressing element 22 operates in the adjacent segment 19.

In fact, according to the present invention, it is possible to command the pressing element 22 by means of the movement member 25 so that it varies its angular speed according to the processing performed, which has determined and quantified the variation in the flow rate of the fluid 1 1.

Depending on the delivery requirements, the angular speed of the pressing element 22 can be constant, or variable continuously or on each occasion.

According to the present invention, these operations are performed, controlled and managed by a control and command unit 27.

The control and command unit 27 can be a microprocessor, or other electric and/or electronic device able to perform one or more of the operations described, possibly by dedicating parts or sub-units thereof to perform the individual operations for which the control and command unit 27 itself is configured.

The filling device 100 can comprise:

- a detection element 31 to determine the angular position of the rotating roller 22;

- a processing unit 32 configured to determine the volumes Vi of fluid 1 1 contained in the sectors Si sequentially defined by angular segments of the flexible tube 14, including the adjacent segment 19, between the initial contact of the rotating roller 22 and the exit of the exit extension 21 ;

- a memorization unit 33 configured to record, for each predefined quantity of fluid 1 1 to be delivered, the circumferential starting and stopping position of the rotating roller 22, wherein the predefined quantity to be delivered into each container corresponds to the sum of the volumes Vi contained in a number of sectors Si and/or in angular portions thereof, affected by the rotating roller 22; - at least one sensor 34 to detect the instantaneous quantity of fluid 1 1 delivered;

- a control and command unit 27 configured to selectively activate the rotating roller 22 to deliver in succession into the containers the predefined quantity of fluid 11 in relation to the circumferential starting position of the rotating roller 22; said control and command unit 27 being configured to compare the instantaneous quantity detected by the sensor 34 with the predefined quantity to be delivered in order to deactivate the rotating roller 22 when the predefined quantity to be delivered has been reached.

The control and command unit 27 can be configured to determine the position of the pressing element 22 on each occasion, to process the volumes Vi of fluid 1 1 relating to the individual sectors Si affected by the pressing element 22 in rotation in relation to the circumferential path. According to possible embodiments, the control and command unit 27 is configured to continuously compare the volume of fluid 1 1 displaced on each occasion with the volume of fluid 1 1 to be delivered, and to command the pressing element 22 to stop when the defined and precise volume of fluid 1 1 to be delivered has been reached.

Since the starting position of the pressing element 22 and the volume of fluid 1 1 to be delivered are known, the control and command unit 27 can be configured to determine the circumferential path that the pressing element 22 has to perform to deliver the defined and precise volume of fluid 1 1 to be delivered.

Formulations of the present invention also provide a peristaltic pump 10 comprising a control and command unit 27 to deliver precise and accurate quantities of fluid.

It is clear that modifications and/or additions of parts can be made to the method to use and control a peristaltic pump 10, and the corresponding peristaltic pump 10 using said method as described heretofore, without departing from the field and scope of the present invention.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of method to use and control a peristaltic pump 10, and the corresponding peristaltic pump 10 using said method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.