Patent Publication Number: US-10788036-B2

Title: Peristaltic pump

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is a National Stage of International Application No. PCT/IB2016/050058, filed Jan. 7, 2016, which claims priority to the Italian Patent Application No. RM2015A000007, filed Jan. 8, 2015. The entire disclosures of the above patent applications are hereby incorporated herein by reference. 
     FIELD 
     The present invention concerns a peristaltic pump, in particular a dosing pump, provided with an electronic board made in a simple, reliable, efficient and inexpensive way, consequently reducing the cost of the peristaltic pump. Moreover, the arrangement of the electronic components allows to simplify the assembling, installation and maintenance operations, at the same time reducing their costs. 
     BACKGROUND 
     In the following of the present description reference will be mainly made to peristaltic dosing pumps. However, it must be noted that the peristaltic pump according to the invention may be also different from a dosing pump and used in any hydraulic circuit for applications different from mixing, such as for instance dispensing of beverages or syrups, still remaining within the scope of protection of the present invention. 
     Moreover, in the following reference will be made to a peristaltic pump having a specific shape devoid of projections on the side walls, that is compact and applicable to a wide variety of different structures, wherein the electronic and mechanical components (e.g. an electronic board and a reduction gear) are coupled inside the pump through snap-fits. However, it must be noted that the peristaltic pump according to the invention may also have different shapes and arrangements of coupling of the electronic and mechanical components different from snap-fit connection means, still remaining within the scope of protection of the present invention. 
     It is known that mixing apparatuses are widespread. In particular, in the field of cleaning and disinfection of surfaces, such apparatuses allow both water-only treatment and addition of concentrated chemicals, such as for instance disinfectants, soaps, wet foams and dry foams. Such apparatuses comprise dosing pumps which contribute to mixing of the various substances with water and to dispensing the obtained mixture according to accurate dosages. 
     A commonly used type of dosing pump is the peristaltic pump, thanks to its generally simple operation that allows an accurate dosage. As known, a peristaltic pump comprises (at least) one tube that is squeezed by two or more rollers (or similar elements) with which a rotor set in rotation by an electric motor is provided; the ends of the tube are connected to a first and second ducts, each one of which is advantageously provided with a respective joint, and both the first and the second ducts may alternatively operate as inlet duct and as outlet duct, depending on the direction of rotation of the rotor. When the duct operating as inlet duct is connected to a fluid source (for instance a hydraulic supply or a tank), thanks to the pressure variations created in the various portions of the tube separated by the squeezing rollers, the fluid is aspirated in the tube and is dispensed from the duct operating as outlet duct. 
     Some prior art peristaltic pumps are disclosed in documents US 2007/0148010 A1, EP 2098729 A1, US 2010/0129248 A1, US 2013/0251561 A1. 
     However, the prior art peristaltic pumps suffer from some drawbacks. 
     In particular, the electronic components have complex arrangements which increase their manufacture costs. 
     SUMMARY 
     Therefore, it is an object of the present invention to allow in a simple, reliable, efficient and inexpensive way to implement the electronic control of a peristaltic pump, in particular a dosing pump. 
     It is another object of the present invention to make assembling and installation and maintenance interventions simple and fast and, consequently, inexpensive. 
     It is specific subject matter of the present invention a peristaltic pump, in particular a dosing pump, comprising un housing, containing an electric motor, and a head configured to be coupled to the housing, the head housing a tube comprising two accessible ends and a rotor provided with two or more squeezing elements configured to squeeze the tube, the rotor being configured to be driven by the electric motor when the head is coupled to the housing, wherein the housing further contains a printed circuit board configured to control the peristaltic pump and to supply power to the electric motor, the printed circuit board being provided with two slots, configured to house two power supply terminals of the electric motor insertable into the two slots, and with two or more protruding male blade terminals, configured to be connected to external female blade terminals of an external power supply, the printed circuit board being substantially triangular and configured to be obtained from a pair of printed circuit boards identical to each other obtainable by separating two antisymmetric portions of a rectangular board along a section line that is antisymmetric with respect to or coincident with a diagonal of the rectangular board. 
     According to another aspect of the invention, the printed circuit board may be configured to be obtained from a pair of printed circuit boards identical to each other obtainable by separating two antisymmetric portions of a square board along a section line that is antisymmetric with respect to or coincident with a diagonal of the square board. 
     According to a further aspect of the invention, said section line may be partially arranged on said diagonal, whereby said printed circuit board is provided with at least one pair of portions being offset from said diagonal, wherein a first portion of the pair is projecting with respect to said diagonal and a second portion of the pair is recessed with respect to said diagonal. 
     According to an additional aspect of the invention, said two or more protruding male blade terminals may be Faston blade terminals. 
     According to another aspect of the invention, the printed circuit board may be provided with one or more trimmers for adjusting the speed of the electric motor accessible from at least one slot of the head. 
     According to a further aspect of the invention, the printed circuit board may be provided with one or more pairs of electrical terminals configured to be connected to one or more respective trimmers for adjusting the speed of the electric motor coupled to the head and accessible from the outside. 
     According to an additional aspect of the invention, at least one side wall of the housing may comprise at least one notch configured to house two or more electrical terminals for supplying power to the printed circuit board. 
     According to another aspect of the invention, said two or more electrical terminals housed in said at least one notch may be male or female terminals, optionally Faston blade ones, configured to connect to corresponding external female or male terminals for making male-female electrical connections. 
     According to a further aspect of the invention, said two or more electrical terminals housed in said at least one notch may be housed in at least one duct that is in turn capable to be housed in said at least one notch. 
     According to an additional aspect of the invention, said at least one duct may be hinged within said at least one notch. 
     According to another aspect of the invention, the printed circuit board may be coupled to the housing through snap-fit connection means. 
     According to a further aspect of the invention, said snap-fit connection means may comprise snap-fit teeth with which the printed circuit board is provided which are configured to insert into corresponding slots of at least two side walls of the housing. 
     According to an additional aspect of the invention, the snap-fit teeth may be configured to slide, while assembling the peristaltic pump, along corresponding alignment guides with which said at least two side walls of the housing are provided down to insert into the slots, whereby, while the teeth slide along the corresponding alignment guides, the printed circuit board and said at least two side walls of the housing to which the corresponding alignment guides belong elastically bend. 
     According to another aspect of the invention, the printed circuit board may be removably coupled to the housing. 
     The advantages offered by the peristaltic pump according to the invention are evident. 
     In particular, the peristaltic pump according to the invention has a control printed circuit board having a configuration such that two boards are obtainable (in an antisymmetric way) by separating two portions of a rectangular or square board along a section line, not necessarily but optionally at least partially arranged along a diagonal of the rectangle or square. This allows to minimise the cost of the control printed circuit board of the peristaltic pump. 
     Also, the peristaltic pump may be optionally devoid of any wiring, and the power supply of the electric motor may be advantageously made through male-female electrical connectors, optionally Faston blade connectors, wherein the peristaltic pump is provided with two or three male terminals or with two or three female terminals, optionally two female terminals, which do not protrude from the side walls of the housing of the pump. This allows to further simplify the assembling, installation and maintenance operations, at the same time reducing their costs with respect to the prior art pumps. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The present invention will be now described, by way of illustration and not by way of limitation, according to its preferred embodiments, by particularly referring to the Figures of the annexed drawings, in which: 
         FIG. 1  shows a front view ( FIG. 1 a   ), a left side view ( FIG. 1 b   ), a top plan view ( FIG. 1 c   ), a bottom plan view ( FIG. 1 d   ) and a rear view ( FIG. 1 e   ) of a preferred embodiment of the peristaltic pump according to the invention; 
         FIG. 2  shows a exploded perspective view of the housing, and of the components contained therein, of the peristaltic pump of  FIG. 1 ; 
         FIG. 3  shows a top plan view ( FIG. 3 a   , wherein lower hidden components are also shown), a front view ( FIG. 3 b   ) and a right side view ( FIG. 3 c   ) of a part of the components contained within the housing of  FIG. 2 ; 
         FIG. 4  shows a first top plan view ( FIG. 4 a   ) and a section view according to the plane AA of  FIG. 4 a    ( FIG. 4 b   ) of the housing and of a part of the components contained therein, as well as a front view ( FIG. 4 c   ) and a top plan view ( FIG. 4 d   ) of a toothed wheel of the peristaltic pump of  FIG. 1 ; 
         FIG. 5  shows a top plan view of the housing, and of the components contained therein, of the peristaltic pump of  FIG. 1 ; 
         FIG. 6  shows a perspective front section view according to the plane BB of  FIG. 5  ( FIG. 6 a   ), an enlargement of a first particular ( FIG. 6 b   ) and an enlargement of a second particular ( FIG. 6 c   ) of such perspective front section view of  FIG. 6   a;    
         FIG. 7  shows a second top plan view of the housing, and of a part of the components contained therein, of the peristaltic pump of  FIG. 1 ; 
         FIG. 8  shows a section view according to the plane CC of  FIG. 7  ( FIG. 8 a   ) and an enlargement of a particular ( FIG. 8 b   ) of the section view of  FIG. 8   a;    
         FIG. 9  shows a top plan view of a square printed circuit board for obtaining two printed circuit boards of the type used in the peristaltic pump of  FIG. 1 ; 
         FIG. 10  shows a top plan view ( FIG. 10 a   ) and a right side view ( FIG. 10 b   ) of a first arrangement of a bracket attached to the peristaltic pump of  FIG. 1 , a top plan view ( FIG. 10 c   ) and a right side view ( FIG. 10 d   ) of a second arrangement of a bracket attached to the peristaltic pump of  FIG. 1 , a top plan view ( FIG. 10 e   ) and a right side view ( FIG. 10 f   ) of a third arrangement of a bracket attached to the peristaltic pump of  FIG. 1 , a top plan view ( FIG. 10 g   ) and a right side view ( FIG. 10 h   ) of a fourth arrangement of a bracket attached to the peristaltic pump of  FIG. 1 , a top plan view ( FIG. 10 i   ) and a right side view ( FIG. 10 j   ) of a fifth arrangement of a bracket attached to the peristaltic pump of  FIG. 1 , a top plan view ( FIG. 10 k   ) and a right side view ( FIG. 10 l   ) of a sixth arrangement of a bracket attached to the peristaltic pump of  FIG. 1 , a top plan view ( FIG. 10 m   ) and a right side view ( FIG. 10 n   ) of a seventh arrangement of a bracket attached to the peristaltic pump of  FIG. 1 , and a top plan view ( FIG. 10 o   ) and a right side view ( FIG. 10 p   ) of an eighth arrangement of a bracket attached to the peristaltic pump of  FIG. 1 ; 
         FIG. 11  shows a perspective view of the fifth arrangement of  FIGS. 10 i  and 10 j    fixed to an external wall ( FIG. 11 a   ), a perspective view of the third arrangement of  FIGS. 10 e  and 10 f    fixed to an external wall ( FIG. 11 b   ), a perspective view of the seventh arrangement di  FIGS. 10 m  and 10 n    fixed to an external wall ( FIG. 11 c   ), a perspective view of the first arrangement di  FIGS. 10 a  and 10 b    fixed to an external wall ( FIG. 11 d   ), a perspective view of the fourth arrangement di  FIGS. 10 g  and 10 h    fixed to an external wall ( FIG. 11 e   ), a perspective view of the eighth arrangement di  FIGS. 10 o  and 10 p    fixed to an external wall ( FIG. 11 f   ), and a perspective view of the second arrangement di  FIGS. 10 c  and 10 d    fixed to an external wall ( FIG. 11 g   ); 
         FIG. 12  shows a top plan view ( FIG. 12 a   ) and a right side view ( FIG. 12 b   ) of a first orientation of coupling of the head to the housing of the peristaltic pump of  FIG. 1 , a top plan view ( FIG. 12 c   ) and a right side view ( FIG. 12 d   ) of a second orientation of coupling of the head to the housing of the peristaltic pump of  FIG. 1 , a top plan view ( FIG. 12 e   ) and a right side view ( FIG. 12 f   ) of a third orientation of coupling of the head to the housing of the peristaltic pump of  FIG. 1 , and a top plan view ( FIG. 12 g   ) and a right side view ( FIG. 12 h   ) of a fourth orientation of coupling of the head to the housing of the peristaltic pump of  FIG. 1 ; 
         FIG. 13  shows two perspective front views of the first orientation of  FIGS. 12 a  and 12 b    wherein the head and the housing are separated ( FIG. 13 a   ) and coupled ( FIG. 13 b   ), two perspective front views of the second orientation of  FIGS. 12 c  and 12 d    wherein the head and the housing are separated ( FIG. 13 c   ) and coupled ( FIG. 13 d   ), two perspective front views of the third orientation of  FIGS. 12 e  and 12 f    wherein the head and the housing are separated ( FIG. 13 e   ) and coupled ( FIG. 13 f   ), and two perspective front views of the fourth orientation of  FIGS. 12 g  and 12 h    wherein the head and the housing are separated ( FIG. 13 g   ) and coupled ( FIG. 13 h   ); and 
         FIG. 14  shows a perspective front right view ( FIG. 14 a   ), a perspective front left view ( FIG. 14 b   ), a perspective rear right view ( FIG. 14 c   ) and a perspective rear left view ( FIG. 14 d   ) of a bracket applicable to the peristaltic pump of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     In the Figures identical reference numerals will be used for alike elements. 
     In the following of the description, the directional terminology, such as “right”, “left”, “front”, “rear”, “base”, “top”, “upper”, “lower”, “side”, etc., is used with reference to the Figures of the attached drawings. Since components and/or elements and/or embodiments of the present invention can be positioned and/or operated in several different orientations, the directional terminology is merely used by way of example and not by way of limitation. 
     With reference to  FIG. 1 , it may be observed that a preferred embodiment of the peristaltic pump according to the invention is a dosing pump having a housing  100  and a head  200  which may be removably coupled to each other. As it will be illustrated later, the housing  100  contains the electrical components, e.g. the control printed circuit board and the electric motor, and the reduction gear of the peristaltic pump; in particular, the housing  100  substantially has the shape of a rectangular parallelepiped devoid of a face (i.e., the five external surfaces of its walls, devoid of projections and possibly provided with holes and/or notches, are planar and lie on the faces of a rectangular parallelepiped—whereby each side wall is configured to rest on an external planar wall), in particular a rectangular parallelepiped close to a cubic shape, wherein the dimensions of the three sides do not differ from each other by more than 30%. In the preferred embodiment, the housing  100  has a square base having side L and height H 100 , wherein the height H 100  is equal to about 80% of L:
 
 H   100 =0.8· L  
 
In other words, the housing  100  substantially has the shape of a rectangular parallelepiped with square base the inside of which is accessible from the missing face of it; conventionally, in the following of the description it will be assumed that the missing wall of the housing  100  is the upper wall, whereby the housing  100  has hollow top. As shown in particular in  FIG. 1 e   , the rear wall of the housing  100  comprises a notch  105  configured to house a duct  108  (shown in  FIG. 11 e   , where it is shown that the duct  108  is optionally orientable since it has the upper end hinged within the notch  105 ) that houses two electrical terminals for supplying power to the printed circuit board contained within the housing  100 ; advantageously, the two electrical terminals are male terminals, optionally Faston blade ones, configured to connect with corresponding external female terminals for making male-female electrical connections. Other embodiments of the peristaltic pump according to the invention may be devoid of the duct  108  and/or comprise three (instead of two) power electrical terminals and/or terminals different from male Faston blade terminals (e.g. female Faston terminals, or male or female terminals not of Faston type).
 
     Other embodiments of the peristaltic pump according to the invention may have other specific dimensions of the three sides of the rectangular parallelepiped shape of the housing  100  (on the faces of which the five external surfaces of its walls lie), the base of which is in general a rectangle instead a square (a square, in the context of the present description and claims, is to be construed as a particular case of rectangle); optionally, the two sides a and b of the base rectangle and the height H 100 =h of the rectangular parallelepiped differ from each other by not more than 30%, whereby such three sides satisfy one of each one of the following three pairs of inequalities: 
     
       
         
           
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     Slots  610  configured to allow a snap-fit connection with some plates contained in the same housing  100 , as it will be better illustrated later with reference to  FIGS. 5 and 6 , are present on the four side walls of the housing  100 . 
     The head  200  of the peristaltic pump houses a rotor provided with two or more (optionally two or three) rollers (or similar elements) and the tube that is squeezed by the rollers; in this regard, the rotor, the rollers and the tube are not shown in the Figures. The head  200  has a hollow base configured to be coupled to the top of the housing  100  (i.e. in correspondence of the missing upper wall of the latter), where the hollow base of the head  200  is delimited by four side walls arranged on the side faces of a rectangular parallelepiped having square base having side L (equal to the side of the square base of the housing  100 ). The head  200  superiorly comprises a projecting upper portion  230  in turn provided with a projection  235 . The whole height H 200  of the head  200 , excluding the projection  235 , is equal to about 37% of the height H 100  of the housing  100 :
 
 H   200 =0.37· H   100  
 
whereby the whole height H P  (excluding the projection  235 ) is larger than the side L of the base square of the housing  100  (and of the head  200 ) by about 17%, i.e.:
 
 H   P   =H   100   +H   200 =1.17· L  
 
     Other embodiments of the peristaltic pump according to the invention may have other specific shapes and dimensions of the head  200 , that still has a hollow base configured to be coupled to the top of the housing  100  (i.e. in correspondence of the missing upper wall of the latter), wherein the head  200  is contained or inscribable in a rectangular parallelepiped having base identical to the base of the rectangular parallelepiped of the housing  100  and height H 200  optionally smaller than the height H 100  of the housing  100  and more optionally ranging from 20% to 50% of the latter:
 
0.2· H   100   ≤H   200 ≤0.5· H   100  
 
When the head  200  is coupled to the housing  100 , the hub of the rotor is mechanically connected to the reduction gear housed within the housing  100  so that the rotor is set in rotation by the electric motor, also housed within the housing  100 , when this is operated, whereby the rollers are set in rotation thus squeezing the tube according to a peristaltic operation. A first and a second joints  210  and  220  with which two ducts  215  and  225  are provided, each one connected to a respective end of the tube, protrude from the head  200 ; in particular, other embodiments of the peristaltic pump according to the invention may be devoid of the joints  210  and  220 .
 
     Moreover, the features of the shape of the peristaltic pump (in particular with reference to the housing  100  and head  200 ) devoid of projections on the side walls of the housing  100  are not features essential to the invention. 
     Furthermore, the head  200  is provided on an upper surface easily accessible with (at least) one slot  240  for accessing two adjusting electronic components, also known as trimmers, for adjusting the speed of the (electric motor and, consequently, of the) rotor of the head  200 ; such electronic components are on a printed circuit board housed within the housing  100 , as it will be illustrated later. In particular, other embodiments of the peristaltic pump may comprise more than one slot for accessing the trimmers (which may be also in a number different from two, for instance only one trimmer or three or more trimmer) and/or one or more slots for accessing the trimmers in position different from that shown in the Figures for the preferred embodiment of the peristaltic pump according to the invention. The shape of the slot(s) for accessing the trimmers is not a feature essential to the invention. 
     With reference to  FIGS. 2-4 , it may be observed that the housing  100  contains an electric motor  130 , configured to set a main pinion  135 , that is inferiorly positioned (i.e. towards the base of the housing  100 ), in rotation, and a reduction gear comprising a first toothed wheel  120  provided with a first secondary pinion  121 , a second wheel  122  provided with a second secondary pinion  123 , a third wheel  124  provided with a third secondary pinion  125 , and a fourth wheel  126  provided with a fourth secondary pinion  127 , superiorly positioned at the centre of the hollow top of the housing  100 . As shown in  FIGS. 4 c  and 4 d   , the toothed wheels  120 ,  122 ,  124  and  126  of the reduction gear are all equal to the same type and size of toothed wheel  20  provided with secondary pinion  21 , the base of which has a smooth collar  22 , wherein the toothed wheel  20  has an axial through hole  22  in which an axis may be inserted. Other embodiments of the peristaltic pump according to the invention may comprise a reduction gear comprising two or more toothed wheels different from each other. 
     In particular, the main pinion  135  is configured to interact with the first toothed wheel  120 , the (first) secondary pinion  121  of which is in turn configured to interact with the second toothed wheel  122 , the (second) secondary pinion  123  of which is in turn configured to interact with the third toothed wheel  124 , the (third) secondary pinion  125  of which is in turn configured to interact with the fourth toothed wheel  126 , the (fourth) secondary pinion  127  of which is in turn configured to be mechanically connected to the hub of the rotor housed within the head  200 , when the latter is coupled to the housing  100 , so that the rotor is set in rotation when the electric motor is operated. Other embodiments of the peristaltic pump according to the invention may comprise a different arrangement of the reduction gear, comprising one or more toothed wheels which may be also devoid of respective secondary pinions. 
     The housing  100  further contains a lower alignment plate  140  and an upper alignment plate  150  configured to be snap-fit connected to the housing  100  in respective positions, so as to make the toothed wheels  120 ,  122 ,  124  and  126  of the reduction gear appropriately align, also with the aid of the internal surface of the base of the housing  100 . In particular, the axis  136  of the first toothed wheel  120  has the lower end positioned in a corresponding notch (not shown) of the internal surface of the base of the housing  100  and the upper end positioned in a respective notch of the lower surface of the lower alignment plate  140  (the corresponding protrusion  146  of which is visible on the upper surface); similarly, the axis  137  of the second toothed wheel  122  has the lower end positioned in a corresponding notch (not shown) of the internal surface of the base of the housing  100  and the upper end positioned in a respective notch of the lower surface of the lower alignment plate  140  (the corresponding protrusion  147  of which is visible on the upper surface); the axis  138  of the third toothed wheel  124  has the lower end positioned in a corresponding notch of a protrusion (not shown) of the internal surface of the base of the housing  100  and the upper end positioned in a respective notch of the lower surface of the upper alignment plate  150  (the corresponding protrusion  158  of which is visible on the upper surface), whereby the third toothed wheel  124  is positioned just beneath the lower alignment plate  140  and the third secondary pinion  125  exits from a through hole  141  thereof and is positioned between the lower alignment plate  140  and the upper alignment plate  150 , so that its collar  128  is configured to rotate inside the edge of the through hole  141 ; the axis  139  of the fourth toothed wheel  126  is inserted in a through hole  142  of the lower alignment plate  140  and has the lower end positioned in a corresponding notch (not shown) of the internal surface of the base of the housing  100  and the fourth secondary pinion  127  exits from a through hole  151  of the upper alignment plate  150 , so that its collar  129  is configured to rotate inside the edge of the through hole  151 , whereby the fourth toothed wheel  126  is positioned between the lower alignment plate  140  and the upper alignment plate  150 . 
     The housing  100  also contains a printed circuit board  160  for controlling the peristaltic pump, that is provided with two slots  161 , configured to house the two power supply terminals  131  of the electric motor  130  insertable into the two slots  161  (as shown in greater detail in  FIG. 8 ), with two downwardly projecting male blade terminals  162 , for connection to an external power supply (through corresponding terminals housed within the duct  108  shown in  FIG. 11 e   ), and with two trimmers  163  for adjusting the speed of the electric motor and, consequently, of the rotor of the head  200 . Furthermore, the housing  100  contains a protective plate  170  (not shown in  FIGS. 3 and 4 ), optionally made of plastics, configured to snap-fit connect on the perimeter of the board  160  so as to cover the same board  160 . 
     With reference to  FIGS. 5 and 6 , it may be observed that the lower alignment plate  140  and the upper alignment plate  150 , optionally made of plastics, are provided with snap-fit teeth  609  which are configured to insert into corresponding slots  610  of at least two, optionally three, more optionally four, side walls of the housing  100 . In particular, while assembling the peristaltic pump, the snap-fit teeth  609  are slid along corresponding alignment guides  608 , with which the side walls of the housing  100  are provided, down to insert into the slots  610 ; obviously, while the teeth  609  slide along the corresponding alignment guides  608 , the plate to which the teeth  609  belong and the side walls of the housing  100  to which the corresponding alignment guides  608  belong elastically bend. In particular, the lower alignment plate  140  and the upper alignment plate  150  are configured to be snap-fit connected to the housing  100 , in a removable or not removable manner. 
     In other words, the peristaltic pump according to the invention is provided with a reduction gear integrated inside the housing  100  that uses a single type of toothed wheel provided with pinion, advantageously made of plastics. All the components of the reduction gear are fixed through plates, also advantageously made of plastics, coupled to the housing  100  through snap-fits, without using any screw. Furthermore, power is supplied to the electric motor through terminals which do not create any projection nor any wiring. This allows to simplify assembling, installation and maintenance operations, at the same time reducing their costs, unlike the prior art peristaltic pumps which use commercial gear motors fixed with screws inside the casing. Moreover, the arrangement of the peristaltic pump according to the invention is compact and handy. 
     Moreover, the features related to the snap-fit connection (devoid of screws and similar elements, i.e. exclusively with snap-fits) of the components contained within the housing  100  and related to the reduction gear are not features essential to the invention. 
     Making reference also to  FIGS. 7 and 8  (wherein the housing  100  is shown devoid of the protective plate  170 ), it may be observed that the printed circuit board  160  for controlling the peristaltic pump has a shape close to the one of an equilateral right triangle. As shown in  FIG. 9 , this is particularly advantageous since it is possible to obtain from a square printed circuit board  900 , provided with a central hole  910 , it is possible to obtain two control printed circuit boards  160 A and  160 B usable in two peristaltic pumps according to the invention; in particular, the two boards  160 A and  160 B are obtainable (in an antisymmetric way) by separating the two portions of the square board  900  along a section line  930  having three portions: a central portion around the central hole  910  along a diagonal of the square board  900  and two end portions being slightly offset from said diagonal (protruding when considered with reference to the respective control printed circuit board  160 A or  160 B), along which diagonal the slots  161  (configured to house the power supply terminals  131  of the electric motor  130 ) of both boards  160 A and  160 B are located, whereby each control printed circuit board  160 A or  160 B has a portion projecting with respect to the diagonal provided with the slots  161  and a portion recessed with respect to the diagonal. This allows to minimise the cost of the control printed circuit board  160  of the peristaltic pump. Optionally, also the printed circuit board  160  for controlling the peristaltic pump snap-fit connects to the side walls of the housing  100  similarly to what illustrated with reference to the lower alignment plate  140  and upper alignment plate  150 . 
     Other embodiments of the peristaltic pump according to the invention may have the printed circuit board having a similar configuration, wherein two boards are obtainable (in an antisymmetric way) by separating two portions of a rectangular or square board along a section line, not necessarily but optionally at least partially arranged along a diagonal of the rectangle or square, and wherein optionally the two boards are provided with at least one pair of portions being slightly offset from such diagonal, wherein a first portion of the pair is projecting with respect to the diagonal and a second portion of the pair is recessed with respect to the diagonal. 
     Moreover, the features related to the electronics comprising a control printed circuit board having the specific configuration illustrated with reference to  FIG. 7-9  may be present in the peristaltic pump according to the invention independently from the other features, i.e. independently from the shape of the peristaltic pump (in particular with reference to the housing  100  and head  200 ) devoid of projections on the side walls of the housing  100 , and independently from the features related to the snap-fit connection (devoid of screws and similar elements, i.e. exclusively with snap-fits) of the components contained within the housing  100  and related to the reduction gear, i.e. that the peristaltic pump is also provided with such other features related to the shape and snap-fit connection. 
     Making reference to  FIGS. 10 and 11 , it may be observed that the square base shape of the housing  100  allows to apply a single type of bracket to all the side walls of the same housing  100  at two possible heights with respect to the base of the housing  100 . In fact, with reference also to  FIG. 1 , it may be observed that two pairs of notches are present on all the four side walls of the housing  100  at two different heights: a pair of upper notches  650 A and a pair of lower notches  650 B. In particular, the two upper or lower notches  650 A or  650 B of each pair are advantageously located in proximity of the two edges separating the side wall (to which the upper or lower notches  650 A or  650 B under consideration belong) from the contiguous side walls, and the upper and lower notches  650 A and  650 B are at the same distance from the closest edge. By way of example, with particular reference to  FIG. 11 b   , the upper and lower notches  650 A and  650 B on the front wall  700  are located in proximity of the two edges  750  and  760  separating the front wall  700  from the left side wall  730  and from the right side wall  710 , respectively. As particularly shown in  FIG. 1 , each upper and lower notch  650 A and  650 B on the side walls comprises a pair of holes  660  into which, as shown in detail in  FIG. 14 , a pair of corresponding teeth  815  are insertable, with which corresponding teeth two side engagement elements  810  are provided, having two slabs integrally coupled to each other for forming a L-profile, with which a bracket  800  is provided, which bracket comprises two orthogonal plates  802  and  804  integrally coupled to each other (whereby the bracket  800  is shaped according a L-profile) provided with slots  806  and/or through holes  808  in which screws  850  (or similar fastening means) are insertable for fixing the peristaltic pump to an external wall  950 ; in particular, the two side engagement elements  810  integrally coupled to the plate  802  of the bracket  800 , and the axis of the junction of the two slabs of each one of the two side engagement elements  810  is orthogonal to the axis of the junction of the two plates  802  and  804 . In particular, each one of the two L-shaped side engagement elements  810  of a bracket  800  comprises a pair of teeth  815  on the internal surface of the slab that is outermost with respect to the bracket  800 , between the two forming the side element  810 , that is orthogonal to the two plates  802  and  804 , so that the two side engagement elements  810  engage with two respective pairs of upper or lower notches  650 A or  650 B present on the side walls of the housing  100  adjacent to the side wall on which the plate  802  rests and with respect to which side wall the other plate  804  of the bracket  800  is disposed parallel. In other words, as shown in  FIGS. 10 and 11 , the bracket  800  is configured to couple to the housing  100 , being disposed parallel to a side wall of the housing  100 , through snap-fit insertion of the pairs of teeth of the two side engagement elements  810  in two respective pairs of notches  650 A or  650 B present on the walls adjacent to such parallel side wall of the housing  100 . In particular, the bracket  800  is configured to removably engage with the housing  100 . 
     As shown in  FIGS. 10 and 11 , the peristaltic pump may be fixed to an external wall  950  by fastening a bracket  800  to the housing  100  in the following positions: a first position wherein the bracket is parallel to the rear wall  720  of the housing  100  at the height of the lower notches  650 B ( FIGS. 10 a , 10 b  and 11 d   ); a second position wherein the bracket is parallel to the rear wall  720  of the housing  100  at the height of the upper notches  650 A ( FIGS. 10 c , 10 d  and 11 g   ); a third position wherein the bracket is parallel to the left side wall  730  of the housing  100  at the height of the lower notches  650 B ( FIGS. 10 e , 10 f  and 11 b   ); a fourth position wherein the bracket is parallel to the left side wall  730  of the housing  100  at the height of the upper notches  650 A ( FIGS. 10 g , 10 h  and 11 e   ); a fifth position wherein the bracket is parallel to the front wall  700  of the housing  100  at the height of the lower notches  650 B ( FIGS. 10 i , 10 j  and 11 a   ); a sixth position wherein the bracket is parallel to the front wall  700  of the housing  100  at the height of the upper notches  650 A ( FIGS. 10 k  and 10 l   ); a seventh position wherein the bracket is parallel to the right side wall  710  of the housing  100  at the height of the lower notches  650 B ( FIGS. 10 m , 10 n  and 11 c   ); and an eighth position wherein the bracket is parallel to the right side wall  710  of the housing  100  at the height of the upper notches  650 A ( FIGS. 10 o , 10 p  and 11 f   ). 
     Moreover, it is also possible to fix the peristaltic pump to one or more external walls by fastening two or more brackets  800  to the housing  100 . 
     The preferred embodiment of the peristaltic pump according to the invention shown in the Figures, having the square base of the housing  100 , allows to position the head  200  by orienting the same towards any one of the four sides of the base square of the housing  100 , since in each one of such positions the fourth secondary pinion  127  is configured to be mechanically connected to the hub of the rotor housed within the head  200 , when the latter is coupled to the housing  100 , so that the rotor is set in rotation when the electric motor is operated. Consequently, the preferred embodiment of the peristaltic pump according to the invention permits that:
         the head  200  is coupled to the housing  100  so that the fourth secondary pinion  127  mechanically connects to the hub  250  of the rotor housed within the head  200 , as shown in  FIG. 13 a   , according to a first orientation wherein the first and second joints  210  and  220  protrude with respect to the front wall  700  of the housing  100 , as shown in  FIGS. 12 a , 12 b    and  13   b;      the head  200  is coupled to the housing  100  so that the fourth secondary pinion  127  mechanically connects to the hub  250  of the rotor housed within the head  200 , as shown in  FIG. 13 c   , according to a second orientation wherein the first and second joints  210  and  220  protrude with respect to the right side wall  710  of the housing  100 , as shown in  FIGS. 12 c , 12 d    and  13   d;      the head  200  is coupled to the housing  100  so that the fourth secondary pinion  127  mechanically connects to the hub  250  of the rotor housed within the head  200 , as shown in  FIG. 13 e   , according to a third orientation wherein the first and second joints  210  and  220  protrude with respect to the rear wall  720  of the housing  100 , as shown in  FIGS. 12 e , 12 f  and 13 f   ; and   the head  200  is coupled to the housing  100  so that the fourth secondary pinion  127  mechanically connects to the hub  250  of the rotor housed within the head  200 , as shown in  FIG. 13 g   , according to a fourth orientation wherein the first and second joints  210  and  220  protrude with respect to the left side wall  730  of the housing  100 , as shown in  FIGS. 12 g , 12 h    and  13   h.          

     In the preferred embodiment of the peristaltic pump according to the invention, when the head  200  is coupled according to an orientation different from the first one (wherein the first and second joints  210  and  220  protrude with respect to the front wall  700  of the housing  100  as shown in  FIGS. 12 a , 12 b  and 13 b   ), the two trimmer  163  for adjusting the speed of the electric motor are not accessible, because the slot  240  of the head  200  is not positioned above the trimmers  163  (since the printed circuit board  160  for controlling the peristaltic pump is stably coupled to the housing  100  independently from the orientation of the head  200 ). As a consequence, in this case it is necessary to adjust the two trimmers  163  before coupling the head  200  to the housing  100 . 
     Other embodiments of the peristaltic pump according to the invention may comprise more than one slot for accessing the trimmers, so that these are accessible even in more than one orientation of coupling of the head to the housing that is different from the first orientation. 
     Further embodiments of the peristaltic pump according to the invention may have the adjusting trimmers directly coupled to the head  200  (instead of the printed circuit board), advantageously on the its top so that they are easily accessible, and they may have each adjusting trimmer that is connected to two or more respective electrical terminals (each comprising the number of wires or traces necessary to the connection with a trimmer, for instance two wires or traces) coupled to the head  200 , only one of which, depending on the orientation of the head  200  with respect to the housing  100 , connects to a terminal of the printed circuit board coupled to the housing  100  that corresponds to that trimmer. In this case, the trimmers are always accessible and operative for any orientation of the head  200  with respect to the housing  100 . 
     Further embodiments of the peristaltic pump according to the invention, wherein the base of the housing is rectangular instead of square, allows the head to be coupled to the housing only according to two different orientations, unless they have a square base (or even circular) head that may be coupled to the housing in correspondence of a square shaped (or even circular) upper aperture of the same housing. 
     The preferred embodiments of this invention have been described and a number of variations have been suggested hereinbefore, but it should be understood that those skilled in the art can make other variations and changes without so departing from the scope of protection thereof, as defined by the attached claims.