Dosage pump

Description

[0001] The present invention relates to a dosage pump.

[0002] The pump is adapted particularly but not exclusively for dosing proportionally small amounts of liquids to introduce them in a hydraulic circuit or a system for generating hot water.

[0003] It is known that heating systems particularly for generating sanitary water are subject to the danger of deposits and corrosion due to the presence of calcium and magnesium salts.

[0004] For this reason, it is usual to introduce in the water circuits substances which are adapted to suspend the calcium and magnesium salts, preventing them from precipitating upon heating.

[0005] Dosage pumps, such as the one disclosed and claimed in Italian patent No. 1336867 which is considered to represent the closest prior art in the name of this same Applicant, are currently known which comprise, inside a hollow body to be interposed between portions of piping of a hydraulic circuit, an impeller with vanes, which rotates as a consequence of the flowing fluid and, by way of transmission means and means for mechanical reduction of the rotary motion and means for converting the rotary motion into reciprocating rectilinear motion, moves mechanically associated means for drawing and pumping the liquid to be dosed.

[0006] Such means for drawing and pumping the liquid to be dosed are arranged inside a containment vessel, which is fixed to the hollow body, for said liquid, and are provided by an injection stem which is moved by the motion conversion means so as to enter and exit with its end from a dosage chamber.

[0007] Such chamber is closed by a flow control element, which is pushed closed by elastic means, on the opposite side with respect to the entry side of the injection stem.

[0008] Moreover, the chamber is connected to the inside of the containment vessel on the side of the injection stem and to a channel for connection to a tube for the rise of the dosed liquid toward the hollow body on the side of the flow control element.

[0009] Although these known dosage pumps are extensively used and highly appreciated by the market, they have aspects which can be improved.

[0010] The drawing and pumping means in fact comprise, in addition to the injection stem, an inverted cup-shaped body, with which a tubular element, in which the stem slides, ends in a lower region; the cup-shaped body contains a block with a hole in which the end of the injection stem is suitable to enter without play; the cup-shaped body is closed in a lower region by a cover.

[0011] The block forms a seal against the surface of the cup-shaped body which lies opposite the cover by means of annular gaskets.

[0012] The cup-shaped body, the block and the cover, together with the gaskets, form the dosage chamber and the channel for connection to the liquid riser tube.

[0013] Such dosage pump is therefore structurally complex, since it is constituted by numerous components which, in addition to constituting a cost in themselves, force a certain assembly time, which despite being small, in any case affects assembly costs.

[0014] GB 1 395 206 discloses a dosage pump having a hollow body container.

[0015] US-3 549 048 and US-3 821 963 disclose dosage type pumps provided with a vane type rotating element.

[0016] The aim of the present invention is to provide a dosage pump according to claim 1 which is simpler and easier to assemble than known types of dosage pump.

[0017] Within this aim, an object of the present invention is to provide a dosage pump in which most of the components can be obtained by molding plastic material.

[0018] Another object of the present invention is to provide a dosage pump which can be manufactured cheaply with known systems and technologies.

[0019] This aim and these and other objects, which will become better apparent hereinafter, are achieved by a dosage pump as defined in claim 1.

[0020] Further characteristics and advantages of the invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a sectional side view of a pump according to the invention;

Figure 2 is a view of a detail of Figure 1;

Figure 3 is a top view of a component of the pump according to the invention;

Figure 4 is a sectional view of the component of Figure 3, referenced therein by the line IV-IV;

Figure 5 is a sectional side view of another component of the pump according to the invention;

Figure 6 is a bottom view of the additional component of Figure 5;

Figure 7 is a sectional view of the component of Figure 3, referenced therein by the line VII-VII;

Figure 8 is a side view of the injection stem of the pump according to the invention.

[0021] With reference to the figures, a dosage pump according to the invention is generally designated by the reference numeral 10.

[0022] The pump 10 comprises a hollow body 11, which is adapted to be interposed between pipe portions of a hydraulic circuit, not shown for the sake of simplicity.

[0023] Inside the hollow body 11 there is a rotary element 12 provided with vanes, which rotates as a consequence of the flowing fluid and is associated with means 13 for transmission and mechanical reduction of the rotary motion and with means 14 for converting the rotary motion into a reciprocating rectilinear motion, which in turn are connected to means 15 for drawing and pumping the liquid to be dosed.

[0024] These last means are provided, inside a container 16 for the liquid to be dosed, which is fixed to the hollow body 11, by an injection stem 17, which is moved by the motion conversion means 14 so as to enter, and exit from, a dosage chamber 19 with its end 18.

[0025] The dosage chamber 19 is closed, on the opposite side with respect to the entry side for the injection stem 17, by a flow control element 20, which is pushed closed by elastic means 21.

[0026] The chamber 19 is connected to the inside of the container 16 on the side of the injection stem 17 and to a channel 22 for connection to a tube 23 for the rise of the dosed liquid toward the hollow body 11 on the side of the flow control element 20.

[0027] The chamber 19 and the connecting channel 22 are formed on a single body 24, inside which the flow control element 20 with its elastic closure means 21 is also fitted.

[0028] The single body 24 substantially replaces the various cup-shaped bodies, blocks and corresponding gaskets which form the dosage chamber and the channel for connection to the liquid riser tube in known types of dosage pump mentioned above.

[0029] The production of a single component allows considerable savings both in terms of molds and in terms of assembly operations.

[0030] The injection stem 17 is adapted to move within a tubular guiding element 25, which is rigidly coupled by a first upper end 26 to snap-acting quick-coupling means to a cover 27 of the container 16; the cover 27 in turn is fixed to the hollow body 11.

[0031] A second lower end 28 of the tubular element 25 is arranged so as to press, within the single body 24, against a first annular sealing gasket 29 at the inlet of the dosage chamber 19.

[0032] The flow control element 20 is constituted by a ball and the elastic means 21 which push it are constituted by a helical spring which rests against the bottom of a connecting channel 30 between the dosage chamber 19 and the channel 22 for connection to the riser tube 23.

[0033] The ball is pushed against a second annular sealing gasket 31 arranged at the outlet of the dosage chamber 19.

[0034] Therefore, the dosage chamber 19 contains the first annular sealing gasket 29 arranged at the inlet of the chamber 19, the second annular sealing gasket 31 arranged in abutment against an underlying shoulder 32 at the outlet of the chamber 19, and, interposed between the two gaskets 29 and 31, a spacer ring 33 whose hole allows the passage without play of the end 18 of the injection stem 17.

[0035] The second lower end 28 of the tubular guiding element 25 is formed by protrusions 34 which guide the end 18 of the stem 17.

[0036] These protrusions 34 press against the first gasket 29.

[0037] The tubular guiding element 25 described here by way of nonlimiting example of the invention comprises four of the guiding protrusions 34, which are arranged symmetrically so as to form between them slots 35 for the passage of the liquid to be dosed toward the dosage chamber 19.

[0038] The liquid flows inside the single body 24 through two ports 36 provided in the single body 24 at the slots 35.

[0039] The means for the snap-acting quick connection of the tubular guiding element 25 to the cover 27 of the container 16 are constituted by at least two mutually opposite elastically deformable tabs 37, which protrude in an axial direction.

[0040] The tabs 37 are each provided, at their end, with a tooth 38 which is adapted to snap into engagement against an abutment edge 39 which is formed by the passage hole, provided in the cover 27, for the first end 26 of the tubular guiding element 25.

[0041] Similar quick connection means speed up considerably the assembly of the pump 10 according to the invention, since it is sufficient to push the first end 26 of the tubular element 25 into the corresponding hole of the cover 27 to achieve the coupling of the two components.

[0042] The single body 24 is adapted to be assembled to the tubular guiding element 25 with a quick coupling of the bayonet type.

[0043] The bayonet coupling is constituted by two mutually opposite and symmetrical wings 39, which protrude radially from the second lower end 28 of the tubular element 25.

[0044] The wings 39 enter the single body 24 through two complementary shaped openings 40, which extend in depth along the direction of the axis of the single body 24 until they affect the ports 36 for the inflow of the liquid by a height which is at least equal to the thickness of the wings 39.

[0045] A generic opening 40 is therefore connected to the nearby and underlying port 36; in this manner, the operator who assembles the two components merely inserts the wings 39 of the tubular element 25 in the corresponding openings 40, pushes them to the bottom of the openings 40 and then turns the single body 24 so that the wings 39 slide at the ports 36 in an extraction-preventing configuration in which they abut against the upper edge 36a of said ports.

[0046] The single body 24, the tubular guiding element 25 and the injection stem 17 can be obtained cheaply by molding plastic material.

[0047] The means 14 for converting rotary motion into reciprocating rectilinear motion are constituted by a cam 41, which is keyed on a shaft 42 which is turned by the means 13 for transmission and mechanical reduction of the rotary motion.

[0048] The cam 41 is inserted in a slot 43 which is formed in a head 44 of the injection stem 17.

[0049] The slot 43 has such a width as to allow the complete rotation of the cam 41 inside it without the head 44 of the stem 17 being pushed and moved transversely to the axis of the stem 17; the height of the slot 43 is further such that the cam 41 can push the stem 17 upward and downward.

[0050] In particular, in the embodiment described here by way of non-limiting example of the invention, the cam 41 is constituted by an eccentric disk, the diameter of which is substantially equal to the height of the slot 43.

[0051] In practice it has been found that the invention thus described solves the problems noted in known types of dosage pump.

[0052] In particular, the present invention provides a dosage pump which is simpler and quicker to assemble than known types of dosage pump.

[0053] Moreover, the present invention provides a dosage pump in which most of the components can be obtained by molding plastic material.

[0054] Moreover, the present invention provides a dosage pump which can be manufactured cheaply with known systems and technologies.

[0055] In practice, the materials employed, so long as they are compatible with the specific use, as well as the dimensions, may be any according to requirements and to the state of the art.

[0056] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A dosage pump, of the type comprising a hollow body (11) which is adapted to be interposed between pipe portions of a hydraulic circuit and is provided internally with a rotating element (12) provided with valves, which rotate as a consequence of a flowing fluid and is associated with means (13) for transmission and speed reduction and with means (14) for converting the rotary motion into reciprocating rectilinear motion, which in turn are connected to means (15) for drawing and pumping the liquid to be dosed, said drawing and pumping means being provided, inside a container (16) for said liquid which is fixed to said hollow body (11), by an injection stem (17) which is moved by said rotary motion conversion means (14) so as to enter and exit with an end (18) from a dosage chamber (19), which on the opposite side with respect to the entry side for said injection stem (17) is closed by a flow control element (20), which is pushed closed by eleatic means (21), said dosage chamber (19) being connected to the inside of said container (16) on said opposite side of said injection stem (17) and to a channel (22) for connection to a tube (23) for the rise of the dosed liquid on the side of said flow control element (20) toward said hollow body (11), said dosage pump being characterized in that
said dosage chamber (19) and said connection channel (22) are formed in a single body (24), inside which said flow control element (20) with its elastic closure means (21) is also fitted.

2. The dosage pump according to claim 1, characterized in that said injection stem (17) is adapted to perform a translational motion within a tubular guiding element (25), which is coupled by means of a first upper end (26), with snap-acting quick-coupling means, to a cover (27) of said container (16) which contains the liquid, a second lower end (28) being arranged so as to press, inside said single body (24), against an annular sealing gasket (29) at the inlet of said dosage chamber (19).

3. The dosage pump according to one or more of the preceding claims, characterized in that said flow control element (20) is constituted by a ball and said elastic means (21) which push it are constituted by a helical spring which rests against the bottom of a channel (30) for connection between said dosage chamber (19) and said channel (22) for connection to said riser tube (23), said ball being pushed against an annular sealing gasket (31) which is arranged at the outlet of said dosage chamber (19).

4. The dosage pump according to claims 2 and 3, characterized in that said dosage chamber (19) contains a first annular sealing gasket (29), which is arranged at the inlet of said chamber (19), a second annular sealing gasket (31), which is arranged in abutment against an underlying shoulder (32) at the outlet of said chamber (19), and a spacer ring (33), which is interposed between the two gaskets (29, 31) and whose axial hole allows the passage without play of the end (18) of said injection stem (17).

5. The dosage pump according to claim 4, characterized in that said second lower end (28) of said tubular guiding element (25) is formed by guiding protrusions (34) for said end (18) of the injection stem (17), said protrusions (34) being adapted to press against said first gasket (29).

6. The dosage pump according to claim 5, characterized in that it comprises four of said guiding protrusions (34) which are arranged symmetrically as so as to form between them slots (35) for the passage of the liquid to be dosed toward said dosage chamber (19).

7. The dosage pump according to claim 2, characterized in that said means for the snap-action quick connection of said tubular guiding element (25) to the cover (27) of said container (16) are constituted by at least two mutually opposite elastically deformable tabs (37), which are elongated in an axial direction and are each provided at their end with a tooth (38) which is adapted to snap into engagement against an abutment edge (39) formed by the passage hole, provided in the cover (27), for said first end (26) of the tubular guiding element (25).

8. The dosage pump according to claim 2, characterized in that said single body (24) is adapted to be assembled to said tubular guiding element (25) with a quick coupling of the bayonet type.

9. The dosage pump according to claim 2, characterized in that said single body (24), said tubular guiding element (25) and said injection stem (17) are each obtained by molding plastic material.

10. The dosage pump according to one or more of the preceding claims, characterized in that said means (14) for converting rotary motion into reciprocating rectilinear motion are constituted by a cam (41), which is keyed on a shaft (42) which is turned by said means (13) for transmission and mechanical reduction of rotary motion, said cam (41) being inserted in a slot (43) which is formed in a head (44) of the injection stem (17), said slot (43) having such a width as to allow complete rotation of the cam (41) inside it without said head (44) of the stem (17) being pushed transversely to the axis of said stem (17), said slot (43) also having such a height that said cam (41) can push the stem (17) downward and upward.

11. The dosage pump according to claim 10, characterized in that said cam (41) is constituted by an eccentric disk, whose diameter is substantially equal to the height of said slot (43).

Ansprüche

1. Eine Dosierpumpe von der Art, die einen hohlen Körper (11) umfasst, der ausgebildet ist, um zwischen Rohrabschnitten eines Hydraulikkreises angeordnet zu werden, und innen mit einem sich drehenden Element (12) ausgestattet ist, das mit Flügeln versehen ist, die sich infolge eines strömenden Fluids drehen, und das mit Mitteln (13) zur Übertragung und Geschwindigkeitsreduktion und mit Mitteln (14) zur Umwandlung der Drehbewegung in eine geradlinige Hin- und Herbewegung verknüpft ist, die wiederum mit Mitteln (15) zum Einziehen und Pumpen der zu dosierenden Flüssigkeit verbunden sind, wobei die Einzieh- und Pumpmittel, in einem Behälter (16) für die Flüssigkeit, der an dem hohlen Körper (11) befestigt ist, von einem Einspritzbolzen (17) bereitgestellt werden, der von den Drehbewegungs-Umwandlungsmitteln (14) bewegt wird, um mit einem Ende (18) in eine Dosierkammer (19) einzudringen und aus ihr auszutreten, die an dem Ende, das dem Eintrittsende für den Einspritzbolzen (17) gegenüberliegt, von einem Durchflussregelungselement (20) verschlossen wird, das von elastischen Mitteln (21) in die verschlossene Position gedrückt wird, wobei die Dosierkammer (19) mit dem Inneren des Behälters (16) auf der gegenüberliegenden Seite des Einspritzbolzens (17) und mit einem Kanal (22) für die Verbindung mit einem Rohr (23) für den Aufstieg der dosierten Flüssigkeit auf der Seite des Durchflussregelungselements (20) zu dem hohlen Körper (11) hin verbunden ist, wobei die Dosierpumpe dadurch gekennzeichnet ist, dass die Dosierkammer (19) und der Verbindungskanal (22) in einem einzigen Körper (24) geformt sind, in den auch das Durchflussregelungselement (20) mit seinen elastischen Verschlussmitteln (21) eingepasst ist.

2. Die Dosierpumpe gemäß Anspruch 1, dadurch gekennzeichnet, dass der Einspritzbolzen (17) ausgebildet ist, um eine translatorische Bewegung in einem rohrförmigen Führungselement (25) auszuführen, das an einem ersten oberen Ende (26) über Schnell-Schnappverbindungsmittel mit einer Abdeckung (27) des Behälters (16) gekoppelt ist, der die Flüssigkeit enthält, wobei ein zweites, unteres Ende (28) angeordnet ist, um in dem einzigen Körper (24) gegen eine ringförmige Dichtung (29) am Einlass der Dosierkammer (19) zu drücken.

3. Die Dosierpumpe gemäß einem oder mehreren der obigen Ansprüche, dadurch gekennzeichnet, dass das Durchflussregelungselement (20) aus einer Kugel besteht und die elastischen Mittel (21), die es schieben, aus einer Schraubenfeder bestehen, die zur Verbindung zwischen der Dosierkammer (19) und dem Kanal (22) für die Verbindung mit dem Steigrohr (23) gegen den Boden eines Kanals (30) aufliegt, wobei die Kugel gegen eine ringförmige Dichtung (31) gedrückt wird, die am Auslass der Dosierkammer (19) angeordnet ist.

4. Die Dosierpumpe gemäß Anspruch 2 und 3, dadurch gekennzeichnet, dass die Dosierkammer (19) eine erste ringförmige Dichtung (29) enthält, die am Einlass der Kammer (19) angeordnet ist, eine zweite ringförmige Dichtung (31), die anstoßend gegen eine darunter liegende Schulter (32) am Auslass der Kammer (19) angeordnet ist, und einen Abstandsring (33), der zwischen den zwei Dichtungen (29, 31) angeordnet ist und dessen Axialloch das Hindurchdringen des Endes (18) des Einspritzbolzens (17) ohne Spiel ermöglicht.

5. Die Dosierpumpe gemäß Anspruch 4, dadurch gekennzeichnet, dass das zweite, untere Ende (28) des rohrförmigen Führungselements (25) von Führungsvorsprüngen (34) für das Ende (18) des Einspritzbolzens (17) gebildet wird, wobei die Vorsprünge (34) ausgebildet sind, um gegen die erste Dichtung (29) zu drücken.

6. Die Dosierpumpe gemäß Anspruch 5, dadurch gekennzeichnet, dass sie vier der Führungsvorsprünge (34) umfasst, die symmetrisch so angeordnet sind, dass sie zwischen sich Schlitze (35) für das Hindurchdringen der zu dosierenden Flüssigkeit zu der Dosierkammer (19) hin bilden.

7. Die Dosierpumpe gemäß Anspruch 2, dadurch gekennzeichnet, dass die Mittel zur Schnell-Schnappverbindung des rohrförmigen Führungselements (25) mit dem Deckel (27) des Behälters (16) aus mindestens zwei einander gegenüberliegenden elastisch verformbaren Nasen (37) bestehen, die in einer axialen Richtung verlängert sind und jeweils an ihrem Ende mit einem Zahn (38) versehen sind, der ausgebildet ist, um in eine Widerlagerkante (39) einzugreifen, die von dem in der Abdeckung (27) bereitgestellten Durchgangsloch für das erste Ende (26) des rohrförmigen Führungselements (25) geformt wird.

8. Die Dosierpumpe gemäß Anspruch 2, dadurch gekennzeichnet, dass der einzige Körper (24) ausgebildet ist, um mit einer Schnellverbindung vom Bajonetttyp an dem rohrförmigen Führungselement (25) montiert zu werden.

9. Die Dosierpumpe gemäß Anspruch 2, dadurch gekennzeichnet, dass der einzige Körper (24), das rohrförmige Führungselement (25) und der Einspritzbolzen (17) jeweils durch das Formen von Kunststoffmaterial hergestellt werden.

10. Die Dosierpumpe gemäß einem oder mehreren der obigen Ansprüche, dadurch gekennzeichnet, dass die Mittel (14) zur Umwandlung von Drehbewegung in geradlinige Hin- und Herbewegung aus einem Nocken (41) bestehen, der auf einer Welle (42) verkeilt ist, welche von den Mitteln (13) zur Übertragung und mechanischen Reduktion von Drehbewegung gedreht wird, wobei der Nocken (41) in einen Schlitz (43) eingeführt ist, der in einem Kopf (44) des Einspritzbolzens (17) geformt ist, wobei der Schlitz (43) eine solche Breite hat, dass er die vollständige Drehung des Nockens (41) in seinem Inneren ermöglicht, ohne dass der Kopf (44) des Bolzens (17) transversal zur Achse des Bolzen (17) geschoben wird, wobei der Schlitz (43) auch eine solche Höhe hat, dass der Nocken (41) den Bolzen (17) abwärts und aufwärts schieben kann.

11. Die Dosierpumpe gemäß Anspruch 10, dadurch gekennzeichnet, dass der Nocken (41) aus einer Exzenterscheibe besteht, deren Durchmesser im Wesentlichen gleich der Höhe des Schlitzes (43) ist.

Revendications

1. Pompe de dosage, du type qui comprend un corps creux (11), qui est adaptée pour être interposée entre des parties de canalisation d'un circuit hydraulique et qui est intérieurement dotée d'un élément rotatif (12) doté d'aubes, qui tournent suite à l'écoulement d'un fluide et qui est associée à des moyens (13) de réduction de la vitesse et de transmission et à des moyens (14) destinés à convertir le mouvement rotatif en un mouvement rectiligne de va-et-vient, qui en retour sont reliés à des moyens (15) destinés à tirer et pomper le liquide à doser, lesdits moyens de tirage et de pompage étant dotés, à l'intérieur d'un contenant (16) pour ledit liquide qui est fixé audit corps creux (11), d'une tige d'injection (17) qui est déplacée par lesdits moyens de conversion de mouvement rotatif (14) de façon à entrer dans et sortir de, avec une extrémité (18), une chambre de dosage (19), qui, sur le côté opposé par rapport au côté entrée de ladite tige d'injection (17), est fermée par un élément de commande de flux (20), qui est poussé pour être fermé par des moyens élastiques (21), ladite chambre de dosage (19) étant reliée à l'intérieur dudit contenant (16) sur ledit côté opposé de ladite tige d'injection (17) et à un canal (22) de mise en relation avec un tube (23) pour la montée du liquide dosé du côté dudit élément de commande de flux (20) vers ledit corps creux (11), ladite pompe de dosage étant caractérisée en ce que ladite chambre de dosage (19) et ledit canal de mise en relation (22) sont formés en un corps unique (24), à l'intérieur duquel est également ajusté ledit élément de commande de flux (20) avec ses moyens de fermeture élastiques (21).

2. Pompe de dosage selon la revendication 1, caractérisée en ce que ladite tige d'injection (17) est adaptée pour exécuter un mouvement de translation à l'intérieur d'un élément de guidage tubulaire (25), qui est couplé au moyen d'une première extrémité supérieure (26), avec des moyens d'accouplement rapide par encliquetage, à un couvercle (27) dudit contenant (16) qui contient le liquide, une seconde extrémité inférieure (28) étant agencée de façon à appuyer, à l'intérieur dudit corps unique (24), contre une garniture d'étanchéité annulaire (29) au niveau de l'orifice d'entrée de ladite chambre de dosage (19).

3. Pompe de dosage selon une ou plusieurs des revendications précédentes, caractérisée en ce que ledit élément de commande de flux (20) est constitué par une bille et lesdits moyens élastiques (21) qui la poussent sont constitués par un ressort hélicoïdal qui repose contre le fond d'un canal (30) pour une mise en relation entre ladite chambre de dosage (19) et ledit canal (22) pour une mise en relation avec ledit tube montant (23), ladite bille étant poussée contre une garniture d'étanchéité annulaire (31) qui est agencée au niveau de l'orifice de sortie de ladite chambre de dosage (19).

4. Pompe de dosage selon les revendications 2 et 3, caractérisée en ce que ladite chambre de dosage (19) contient une première garniture d'étanchéité annulaire (29) qui est agencée au niveau de l'orifice d'entrée de ladite chambre (19), une seconde garniture d'étanchéité annulaire (31) qui est agencée en butée contre un épaulement sous-jacent (32) au niveau de l'orifice de sortie de ladite chambre (19), et une bague entretoise (33), qui est intercalée entre les deux garnitures (29, 31) et dont le trou axial permet le passage sans jeu de l'extrémité (18) de ladite tige d'injection (17).

5. Pompe de dosage selon la revendication 4, caractérisée en ce que ladite seconde extrémité inférieure (28) dudit élément de guidage tubulaire (25) est formée par des saillies de guidage (34) pour ladite extrémité (18) de la tige d'injection (17), lesdites saillies (34) étant adaptées pour appuyer contre ladite première garniture (29).

6. Pompe de dosage selon la revendication 5, caractérisée en ce qu'elle comprend quatre desdites saillies de guidage (34) qui sont agencées symétriquement de façon à former entre elles des fentes (35) pour le passage du liquide à doser vers ladite chambre de dosage (19).

7. Pompe de dosage selon la revendication 2, caractérisée en ce que lesdits moyens de mise en relation rapide par encliquetage dudit élément de guidage tubulaire (25) sur le couvercle (27) dudit contenant (16), sont constitués par au moins deux pattes élastiquement déformables mutuellement opposées (37), qui sont allongées dans une direction axiale et qui sont chacune dotées au niveau de leur extrémité d'une dent (38) qui est adaptée pour s'encliqueter en prise contre un bord de butée (39) formé par le trou de passage, prévu dans le couvercle (27), pour ladite première extrémité (26) de l'élément de guidage tubulaire (25).

8. Pompe de dosage selon la revendication 2, caractérisée en ce que ledit corps unique (24) est adapté pour être assemblé audit élément de guidage tubulaire (25) avec un accouplement rapide du type baïonnette.

9. Pompe de dosage selon la revendication 2, caractérisée en ce que ledit corps unique (24), ledit élément de guidage tubulaire (25) et ladite tige d'injection (17) sont chacun obtenus en moulant un matériau plastique.

10. Pompe de dosage selon une ou plusieurs des revendications précédentes, caractérisée en ce que lesdits moyens (14) destinés à convertir un mouvement rotatif en un mouvement rectiligne de va-et-vient sont constitués par une came (41), qui est clavetée sur un arbre (42) qui est mis en rotation par lesdits moyens (13) de transmission et de réduction mécanique d'un mouvement rotatif, ladite came (41) étant insérée dans une fente (43) qui est formée dans une tête (44) de la tige d'injection (17), ladite fente (43) présentant une largeur telle qu'elle permet une rotation complète de la came (41) dans son intérieur sans que ladite tête (44) de la tige (17) soit poussée transversalement par rapport à l'axe de ladite tige (17), ladite fente (43) présentant également une hauteur telle que ladite came (41) peut pousser la tige (17) vers le bas et vers le haut.

11. Pompe de dosage selon la revendication 10, caractérisée en ce que ladite came (41) est constituée par un disque d'excentrique, dont le diamètre est sensiblement égal à la hauteur de ladite fente (43).

Drawing