Abstract:
A dosage pump which includes a pump body and a control means with rest and distribution positions. The control means includes a dosing chamber, a return spring, and a member to ensure friction braking of the sliding movement of the actuating members of the pump.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a metering pump, designed to be mounted by means of a screw, snap-fit, welded connection, etc., on various rigid or flexible receptacles such as bottles, tubes or pots, in particular receptacles containing cosmetic or pharmaceutical products or alternatively food products, of different viscosities which may range from liquid products to products with a creamy consistency. 
   Different types of metering pumps have been on the market for a number of years, all of which require the use of a certain number of parts such as springs, bearings, valves, stoppers and others. The main disadvantage of such pumps is that they are made up of a number of parts and the cost of manufacturing and assembling these parts is high. 
   In order to remedy these disadvantages, metering pumps have already been proposed, which comprise a pump body which can be adapted to fit a receptacle and communicates with the internal part of the latter, as well as control means, cooperating with the pump body to define a metering chamber, which can be operated from the exterior so as to be displaced between a dispensing position and a non-operating position to enable a metered quantity of product to be ejected from the metering chamber to the exterior via an ejection orifice and then transfer a new metered quantity of product from the receptacle to the metering chamber and so on. 
   With this design known from the prior art, the control means are elastically returned from the dispensing position to the non-operating position once they are longer subjected to an external constraint, in order to create a vacuum pressure so that a metered quantity of product can be drawn towards the metering chamber. 
   In spite of their undeniable specific properties, the disadvantage of such metering pumps is that they are often relatively expensive. 
   The objective of the present invention is to overcome these drawbacks by proposing a simple, efficient and reliable metering pump, which is also remarkably inexpensive to manufacture. 
   SUMMARY OF THE INVENTION 
   To this end, the invention relates to a metering pump of the type outlined above, characterised in that the control means are provided in the form of:
         a push button with an ejection orifice and designed to slide in the pump body,   a plunger essentially in the form of a tubular body mounted on the internal part of the push button and cooperating with the pump body to define the metering chamber,   operating elements designed to slide along the pump body as a unit with the push button,   a return spring mounted between the pump body and the push button outside the metering chamber and   means for braking, by means of friction, the sliding motion of the operating elements along the pump body.       

   For the purposes of the invention, the control means have guide elements cooperating with the operating elements to enable the metering chamber to be placed in communication with the ejection orifice or with the internal part of the receptacle. 
   The operating elements are also independent of the push button in the non-operating position but move into to contact with it in the dispensing position as the control elements are displaced between these two positions. 
   As a result of another characteristic feature of the invention, the operating elements have a shoulder on their external face, forming a stop intended to co-operate with a matching shoulder on the internal face of the push button or an element joined to it in order to join these elements as they are displaced in translation along the pump body. 
   For the purposes of the invention, the control elements are so designed that, starting from the non-operating position in which the metering chamber containing a dose of product is in communication with the internal part of the receptacle but is isolated from the ejection orifice, the control means are moved into the dispensing position in two stages, namely, a first stage on the one hand, during which the push button slides inside the pump body independently of the operating elements so as to isolate the metering chamber from the internal part of the receptacle as this chamber is being placed in communication with the ejection orifice, and a second stage on the other hand, during which the push button and the operating elements slide as a unit inside the pump body, and the piston compresses the product disposed in the metering chamber so that it can be ejected through the ejection orifice to the exterior. 
   Conversely, starting from the dispensing position in which the metering chamber contains no product and communicates with the ejection orifice but is isolated from the internal part of the receptacle, the return spring automatically returns the control means to the non-operating position and does so in two stages, namely, a first stage on the one hand, during which the push button slides inside the pump body independently of the operating elements to as to place the metering chamber in communication with the internal part of the receptacle and isolate the metering chamber from the ejection orifice, and, on the other hand, a second stage during which the push button and the operating elements slide as a unit inside the pump body, creating a vacuum pressure so that a metered quantity of product is drawn towards the metering chamber and is so once the two shoulders acting as a stop come into contact. 
   As a result of another feature of the invention, the plunger has a connecting orifice pierced through its body and designed to be placed in communication with the metering chamber and with the ejection orifice. 
   If the metering pump is intended for dispensing liquid products such as perfumes or toilet waters, the connecting orifice may advantageously be linked to a swirl system provided in the internal part of the plunger body and designed to co-operate with the ejection orifice to permit vaporisation and atomisation of this liquid product to the exterior. 
   Clearly, if the metering pump is intended as a means of dispensing more viscous products such as lotions or creams, the plunger body will not be fitted with such a swirl system. 
   In a first embodiment of the invention, the operating elements are the actual plunger itself. 
   This first embodiment is specifically used in the manufacture of promotional samples or mini-metering pumps, known as “spray mini-pumps”, in particular for handbags and as a means of spraying perfume, toilet water, etc. . . . 
   In this first embodiment, the push button has an essentially cylindrical median end-piece on its internal part, surrounded by an annular recess to accommodate the top end of the plunger body. 
   This median end-piece has a circular sealing rib at its periphery, which moves into abutment with the internal face of the plunger body in order to isolate the metering chamber from the connecting orifice, whilst its bottom end has a locating pin acting as a seat for an annular seal provided on the top of a hollow median rod and fixed coaxially on the internal face of the plunger body in order to isolate the metering chamber from the internal part of the receptacle. 
   By virtue of another feature of this first embodiment, the metering chamber is bounded at its top part by the internal face of the plunger body and the external face of the median rod thereof and is designed so that it can be placed in communication with the connecting orifice and the ejection orifice or with the internal part of the receptacle via a dispensing orifice pierced through the top face of the latter and connecting with a longitudinal dispensing groove provided in the internal wall of the plunger body. 
   As a result of another feature of this first embodiment, the ejection orifice is closed off by the body of the plunger in the non-operating position. 
   This feature is of particular advantage because it protects any product “waiting” between the metering chamber and the ejection orifice, which is quite important in terms of delaying oxidation in the case of certain delicate products (perfumes, lotions, . . . ). 
   In a second embodiment of the invention, the plunger forms a unit with the push button and the operating elements are provided in the form of a nozzle with a tubular body closed at its top end and open at its bottom end so that it can be placed in communication with the internal part of the receptacle. 
   The body of the nozzle is designed to slide along the internal face of the plunger body. 
   This second embodiment of the invention lends itself to the manufacture of mini-pumps known as “spray mini-pumps” for handbags, samples, . . . , but also to the manufacture of pumps capable of dispensing larger metered quantities of liquids or more viscous products such as lotions or creams. 
   In the case of this second embodiment, the plunger has an annular seal on its internal face, which moves into abutment with the external periphery of the nozzle body in order to isolate the metering chamber from the connecting orifice or from the internal part of the receptacle. 
   By virtue of another feature of this second embodiment, the metering chamber is bounded at its top part by the internal face of the plunger body and by the external face of the nozzle body and is designed to be placed in communication with the internal part of the receptacle via a cross-passage orifice pierced through the nozzle body, on the one hand, and, on the other, with the connecting orifice and the ejection orifice via a longitudinal dispensing groove provided on the external face of the nozzle body at the same level as the passage orifice. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above mentioned and other features and objects of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
       FIG. 1  is a view in section depicting a metering pump corresponding to the first embodiment of the invention, shown in the non-operating position; 
       FIG. 1   a  is a view in partial section similar to that of  FIG. 1  along a plane denoted by the axis I—I; 
       FIG. 2  is a more detailed view corresponding to  FIG. 1  but showing the pump in the dispensing position; 
       FIG. 3  is a front view of the plunger of this pump, representing the swirl system; 
       FIG. 4  is a view in section depicting a metering pump corresponding to the second embodiment of the invention and illustrating the non-operating position; and 
       FIG. 5  is a view in section corresponding to  FIG. 4  but depicting this same pump in an intermediate position between the non-operating position and the dispensing position. 
   

   Corresponding reference characters indicate corresponding parts throughout the several views. Although the exemplification set out herein illustrates embodiments of the invention, in several forms, the embodiments disclosed below are not intended to be exhaustive or to be construed as limiting the scope of the invention to the precise forms disclosed. 
   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The metering pump illustrated in  FIG. 1  essentially consists of a tubular pump body  1 , which can be adapted to fit on a receptacle, not illustrated, and a push button  2  designed to slide along the internal wall of the pump body  1  between a non-operating position illustrated in  FIG. 1  and a dispensing position illustrated in  FIG. 2 . 
   The pump body  1  is fitted with a plunger tube  3 , enabling the product contained in the receptacle to be drawn in and ejected to the exterior through an ejection orifice  4  provided on a side face of the push button  2 , in a manner that will be described in more detail later on in this description. 
   As illustrated in  FIGS. 1 and 2 , a return spring  5  is housed between the pump body  1  and the push button  2 . 
   Starting from the non-operating position illustrated in  FIG. 1 , the user may displace the push button  2  into the dispensing position illustrated in  FIG. 2  by applying a pressing force F to the top face thereof. 
   The spring  5  automatically returns the push button  2  from this dispensing position to the non-operating position illustrated in  FIG. 1 . 
   The push button also has an essentially cylindrical median end-piece  6  on its internal part, which is surrounded by an annular recess  7  in which the top end of a plunger  8  is inserted. 
   As illustrated in  FIGS. 1 and 2 , the plunger  8  comprises a tubular body  9  inserted in the annular recess  7  of the push button  2  by its top end. 
   As illustrated in  FIGS. 1 and 1   a , the external wall  33  of the annular recess  7  of the push button  2  has a rib  34  forming a key, which co-operates with a matching rib  35  on the tubular body  9  of the plunger  8 , so that these two elements rotate integrally as a unit. 
   The body  9  of the plunger  8  also has a hollow rod  10  at its internal part, which is coaxially affixed to the latter by means of an annular wall  11 . 
   The hollow rod  10  is fitted with an annular seal  12  at its top end. 
   The body  9  of the plunger  8  in turn has a connecting orifice  13  designed to communicate with the ejection orifice  4  of the push button  2  in a manner that will be described later on in the description. 
   The rib  34  and the groove  35  ensure that these two orifices  4 ,  13  are always correctly oriented relative to one another. 
   As illustrated in  FIG. 1 , the plunger tube  3  of the pump body  1  is extended in the internal part of the latter by means of a tubular sleeve  14 , receiving the bottom end of the hollow rod  10  of the plunger  8 . 
   As illustrated in  FIGS. 1 and 2 , the outer periphery of the hollow rod  10  has a bead  27  which rubs against the internal wall of the tubular sleeve  14  of the pump body  1  so that it brakes the sliding action of the plunger  8  in the pump body  1  by means of friction. 
   The tubular sleeve  14  is also surrounded by a collar  15 , on the internal face of which an annular seal  16  on the bottom end of the body  9  of the pump  8  is supported. 
   The tubular sleeve  14  and the collar  15  of the pump body  1  as well as the hollow rod  10  and the bottom part of the body  9  of the plunger  8  therefore bound a metering chamber  17 , which is closed by the annular wall  11  at its top part and is kept sealed from the external periphery of the plunger  8  by the annular seal  16 . 
   As illustrated in  FIGS. 1 and 2 , the return spring  5  is mounted on the pump body  1  to the exterior of the collar  15  and is therefore not in contact with the metering chamber  17 . 
   The top part of the body  9  of the plunger  8  is also fitted with an annular seal  18 , which is constantly applied against the periphery of the end piece  6  to guarantee that this end piece and the plunger  8  are sealed at this level. 
   As illustrated in  FIGS. 1 and 2 , the median end piece  6  of the push button  2  is also fitted with a circular sealing rib  19  on its periphery, which is supported on the internal face of the body  9  of the plunger  8  so that the metering chamber  17  can be isolated from the connecting orifice  13  in a manner that will be described later on in the description. 
   The median end piece  6  of the push button  2  also has a locating pin  20  at its bottom end, forming a seat for the annular seal  12  provided on the hollow rod  10  of the plunger  8  to enable the metering chamber  17  to be isolated from the internal part of the receptacle and to do so in a manner that will be described later in the description. 
   As illustrated in  FIG. 1 , the annular wall  11  of the plunger  8 , which closes off the metering chamber  17  at its top part, has a dispensing orifice  21  pierced through it and opening into a longitudinal dispensing groove  22  provided in the internal wall of the body  9  of the plunger  8 . 
   In addition, and as illustrated in  FIGS. 1 ,  2  and  3 , the connecting orifice  13  is linked to a swirl system  23  via a circular passage  24 , from which rectilinear branches  25  extend, converging on a central passage  26  which can be placed in communication with the ejection orifice  4 , as illustrated in  FIG. 2 , whereas in the non-operating position illustrated in  FIG. 1 , the ejection orifice  4  is closed off by the body  9  of the plunger  8 . 
   The operating mode of this dispensing pump will now be described with reference to  FIGS. 1 and 2 . 
   In the non-operating position illustrated in  FIG. 1 , the top end of the plunger  8  is disposed at a distance X from the top face of the push button  2  and the metering chamber  17  is filled with a metered quantity of the product to be dispensed. 
   The axis of the median passage  26  of the swirl system  23  is also located at a distance X from the ejection orifice  4 . 
   In this position, the circular sealing rib  19  of the median end piece  6  of the push button  2  is supported against the internal face of the body  9  of the plunger  8  and the metering chamber  17  is isolated from the connecting orifice  13  and the ejection orifice  4 . 
   The annular seal  12  of the hollow rod  10  of the plunger  8 , on the other hand, is not supported on its seat  20  and the metering chamber  17  communicates with the internal part of the receptacle. 
   Starting from this non-operating position illustrated in  FIG. 1 , when the user compresses the top face of the push button  2  in the direction of arrow F, this push button is displaced towards the bottom of the drawing inside the pump body  1 , whereas the plunger  8  remains immobile and does so until the top face of the push button  2  comes into contact with the top end of the body  9  of the plunger  8 , i.e. until the distance X between these two elements becomes zero. 
   During this displacement, the locating pin  20  moves into abutment with the annular seal  12  of the hollow rod  10  in order to isolate the metering chamber  17  from the internal part of the receptacle and the circular sealing rib  19  of the end piece  6  is simultaneously moved into position facing the dispensing groove  22  of the body  9  of the plunger  8 , placing the metering chamber  17  in communication with the connecting orifice  13 , whilst the ejection orifice  4  is moved into position alongside the median passage  26  of the swirl system  23 . 
   The metering chamber  17  therefore communicates with the exterior. 
   As illustrated in  FIG. 2 , from the point at which the top end of the body  9  of the plunger  8  is in contact with the top face of the push button  2 , the user continues to compress this push button in the direction of arrow F, driving the plunger  8  in translation along with it and compressing the metered quantity of product disposed in the metering chamber  17 . 
   Under the effect of this compression, the product enclosed in the metering chamber  17  is ejected to the exterior following the route denoted by a broken line and indicated by the arrows a, passing via the dispensing orifice  21  and via the dispensing groove  22  and along the median end piece  6  of the push button  2  to arrive in the connecting orifice  13 , followed by the swirl system  23  and finally through the ejection orifice  4 , having passed through the median passage  26 . 
   This ejection continues until the metering chamber  17  has been totally evacuated in the dispensing position illustrated in  FIG. 2 . 
   In this position, the bottom end  28  of the push button  2  is in a stop position against an opposing surface  29  of the pump body  1 . 
   From this dispensing position, when the user ceases to compress the push button  2  in the direction of arrow F, the spring  5  automatically returns it towards the top of the drawing in the direction of arrow G. 
   During a first phase of this movement, because of the presence of the bead  27  which applies a braking action due to friction, the plunger  8  remains immobile so that the locating pin  20  of the push button  2  is released from the annular seal  12  of the hollow rod  10 , placing the metering chamber  17  in communication with the internal part of the receptacle. 
   The circular sealing rib  19  of the end piece  6  is simultaneously released from the dispensing groove  22  and moves back to its position supported against the internal face of the body  9  of the plunger  8  so as to isolate the metering chamber  17  from the connecting orifice  13 . 
   The plunger  8  therefore remains immobile until a shoulder forming a stop  30 , provided on the internal face of the push button  2 , moves into abutment with a shoulder forming an opposing stop  31  provided on the external face of the body  9  of the plunger  8 . 
   When these two shoulders are in abutment, the top end of the body  9  of the plunger  8  is again disposed at a distance X from the top face of the push button  2 . 
   Starting from this abutment position, the push button  2  drives the plunger  8  with it in translation along the body of the pump  1 . 
   During this movement, the displacement of the plunger  8  relative to the pump body  1  creates a vacuum pressure, causing the product enclosed in the receptacle to be drawn towards the metering chamber  17 , as illustrated by broken lines and schematically indicated by arrows b in  FIG. 1 . 
   The aspirated product therefore passes through the plunger tube  3  and then through the interior of the tubular sleeve  14  of the pump body, followed by the internal part of the hollow rod  10  and between the annular seal  12  and the locating pin  20  of the end piece  6  of the push button  2  before finally arriving in the metering chamber  17 . 
   The latter is therefore filled with product until opposing surfaces  33  and  32  of the pump body  1  and the push button  2  are moved into abutment with one another so that they are finally in the non-operating position illustrated in  FIG. 1 . 
   As illustrated in  FIGS. 4 and 5 , the metering pump also essentially comprises a tubular pump body  101  which can be adapted to fit a receptacle, as well as a push button  102  designed to slide along the internal wall of the pump body  101  between a non-operating position illustrated in  FIG. 4  and a dispensing position, not illustrated. 
     FIG. 5  illustrates the push button  102  in an intermediate position between the non-operating position and the dispensing position. 
   The pump body  101  is fitted with a plunger tube  103  enabling the product contained in the receptacle to be aspirated and ejected to the exterior through an ejection orifice  104  disposed on the side face of the push button  102  in a manner that will be described in more detail later on in the description. 
   In the embodiment illustrated in  FIGS. 4 and 5 , the pump body  101  also has an exterior air intake  140 , which may optionally be dispensed with in certain configurations. 
   A return spring  105  is housed between the pump body  101  and the push button  102 . 
   This spring  105  automatically returns the push button  102  to the non-operating position illustrated in  FIG. 4  when no external constraint is being applied to it. 
   Starting from this non-operating position, the user may displace the push button  102  towards the bottom of the drawing in the direction of the dispensing position by applying a pressing force F to the top face thereof. 
   Furthermore, and as illustrated in  FIGS. 4 and 5 , the push button  102  has a median recess  106  on its internal part, in which the top end of a plunger  108  is fixed, provided in the form of a tubular body. 
   This plunger  108  is therefore joined to the push button  102  during its displacement between the dispensing position and the non-operating position. 
   As illustrated in  FIGS. 4 and 5 , the bottom end of the plunger  108  is fitted with an annular seal  109 , which is constantly supported against the internal face of the pump body  101 . 
   The plunger  108  also has a connecting orifice  113  at its top part, which constantly communicates with the ejection orifice  104  of the push button  102  via a swirl system  123 , similar to the swirl system  23  incorporated in the metering pump illustrated in  FIGS. 1 to 3 . 
   As illustrated in  FIGS. 4 and 5 , the metering pump also has a nozzle  107 , provided in the form of a substantially cylindrical tubular body  110 , which is closed at its top end by a circular front wall  111  and open at its bottom end so as to be placed in communication with the internal part of the receptacle. 
   As illustrated in  FIG. 5 , the plunger tube  103  is extended inside the pump body  101  by means of a tubular sleeve  114 , which receives the bottom end  115  of the tubular body  110  of the nozzle  107  at its internal part. 
   At this level, the tubular body  110  of the nozzle  107  is provided with an external bead  127  which is designed to rub against the internal wall of the tubular sleeve  114  so as to brake the displacement of the nozzle  107  inside the pump body  101 . 
   Furthermore, and as illustrated in  FIGS. 4 and 5 , the plunger  108  has an annular seal  112  at its internal periphery, which is supported against the body  110  of the nozzle  107 . 
   As illustrated in these drawings, the tubular sleeve  114 , the periphery of the pump body  101 , the plunger  108  and the tubular body  110  of the nozzle  107  bound a metering chamber  117 . 
   This metering chamber  117  is hermetically sealed by the annular seal  109  of the plunger  108  and may be isolated from the internal part of the receptacle or the connecting orifice  113  and ejection orifice  104  in a manner that will be described in more detail farther on in the description. 
   As illustrated in  FIGS. 4 and 5 , the return spring  105  is in turn mounted on the exterior of a collar  116  of the pump body  101 , surrounding the tubular sleeve  114 , and is therefore constantly isolated from the metering chamber  117 . 
   The body  110  of the nozzle  107  also has a cross passage  121  pierced through it, on the one hand, and, on the other, a longitudinal dispensing groove  122  in the external face of the nozzle body  110  on the same level as the passage orifice  121 . 
   As will be explained later on in the description, the passage orifice  121  enables the metering chamber  117  to be placed in communication with the internal part of the receptacle, whilst the dispensing groove  122  enables this metering chamber  117  to be placed in communication with the connecting orifice  113  and the ejection orifice  104 . 
   The operating mode of this metering pump will now be described with reference to  FIGS. 4 and 5 . 
   In the non-operating position illustrated in  FIG. 4 , the front wall  111  of the nozzle  107  is located at a distance X from the top face of the push button  102  and the metering chamber  117  is filled with a metered quantity of the product to be dispensed. 
   In this position, the annular seal  112  of the plunger  108  is supported against the external periphery of the body  110  of the nozzle  107  above the dispensing groove  122  so that the metering chamber  117  is isolated from the connecting orifice  113  and ejection orifice  104 . 
   However, the annular seal  112  does not close off the passage orifice  121 , as a result of which the metering chamber  117  communicates with the internal part of the receptacle. 
   Starting from this non-operating position illustrated in  FIG. 4 , when the user compresses the top face of the push button  102  as indicated by arrow F, this push button  102  as well as the plunger  108  are displaced towards the bottom of the drawing inside the pump body  101 , whilst the nozzle  107  remains immobile, and does so until the position illustrated in  FIG. 5  is reached, when the top face of the push button  102  comes into contact with the circular front wall  111  of the nozzle  107 , i.e. until the distance X between these two elements becomes zero. 
   During this displacement, the annular seal  112  moves so that it closes off the passage orifice  121  in order to isolate the metering chamber  117  from the internal part of the receptacle and is simultaneously moved into position facing the dispensing groove  122 . The metering chamber is then placed in communication with the connecting orifice  113  and the ejection orifice  104 . 
   Starting from the point at which the circular front wall  111  of the nozzle  107  makes contact with the top face of the push button  102 , as the user continues to compress the push button  102  in the direction of arrow F, the nozzle  107  is driven in translation with the plunger  108  and push button  102  and the metered quantity of product disposed in the metering chamber  117  is gradually compressed. 
   As illustrated in  FIG. 5 , the product enclosed in the metering chamber  117  is therefore ejected to the exterior along the route indicated by the arrows c, passing via the dispensing groove  122 , then around the external wall of the body  110  of the nozzle  107  in order to arrive in the connecting orifice  113 , followed by the swirl system  123  and finally the ejection orifice  104 . 
   This ejection continues until the plunger  108  has moved into abutment with the pump body  101 , i.e. until the metering chamber  117  has been totally evacuated, in the dispensing position. 
   From this position, when the user ceases to compress the push button  102  in the direction of arrow F, the spring  105  automatically returns this push button  101  and the plunger  108  towards the top of the drawing as indicated by arrow G. 
   During a first phase of this displacement, the nozzle  107  remains immobile due to the presence of the friction bead  127 ; the annular seal  112  is then released from the passage orifice  121 , placing the metering chamber  117  in communication with the internal part of the receptacle. 
   The annular seal  121  is simultaneously moved into abutment with the external periphery of the body  110  of the nozzle  107 , being released from the dispensing groove  122 , and thus isolates the metering chamber  117  from the connecting orifice  113  and ejection orifice  104 . 
   The nozzle  107  therefore remains immobile until the shoulder acting as a stop  130 , provided on the internal face of the plunger  108 , is moved into abutment with the shoulder forming an opposing stop  131  provided thereon. 
   When these two shoulders are in abutment, the circular front wall  111  of the nozzle  107  is again disposed at a distance X from the top face of the push button  102 , in the position illustrated in  FIG. 4 . 
   From this position, the push button  102  and the plunger  108  drive the nozzle  107  with them in translation along the pump body  101 . 
   During this movement, the displacement of the plunger  108  relative to the pump body  101  creates a vacuum pressure, causing the product enclosed in the receptacle to be drawn towards the metering chamber  117  along a route denoted by broken lines and schematically indicated by arrows d in  FIG. 4 . 
   The aspirated product therefore passes through the plunger tube  3 , then on the internal part of the body  110  of the nozzle  107 , before entering the metering chamber  117  via the passage orifice  121 . 
   While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.