Abstract:
The invention concerns a pump for dispensing liquid or semi-liquid product, designed to be used in particular in the pharmaceutical or cosmetic field. The pump comprises a needle valve and a dispensing head manually movable on the pump housing between an inactive position and a punctual product dispensing position. The head includes a first cylinder forming a metering chamber of the pump, which communicates with a take-off tube via a non-return valve, a piston being slidably mounted in said first cylinder. The head also includes a second cylinder wherein is slidably mounted said needle valve, means for elastic return of the needle valve in position for closing an orifice, and means for allowing the liquid to pass between the metering chamber and a second chamber provided at the end of said dispensing head, said second cylinder having a compartment wherein are housed the elastic return means and which is isolated from said second chamber by sealing closure means.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of pending International patent application PCT/FR2006/001029 filed on May 9, 2006 which designates the United States and claims priority from French patent application 0551308 filed on May 20, 2005, the content of which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention concerns a pump for dispensing a liquid or semi-liquid product, designed in particular for sealing a container containing the product to be dispensed. 
         [0003]    The pump according to the invention is particularly, but not exclusively, designed to be used in the pharmaceutical field. 
         [0004]    The pump according to the invention is of the so-called “needle-valve” type, which is to say comprising at the top a needle mounted so as to move freely between a closed position in which it blocks the end opening of the pump, and prevents the dispensing of the product, and an open position in which it allows the liquid to pass through said end opening. 
       BACKGROUND OF THE INVENTION 
       [0005]    Such pumps already exist which, in a standard manner, comprise a first cylinder forming a pump chamber, which communicates with an intake tube by means of a check valve, and in which a hollow piston is slidingly mounted. They also comprise a second cylinder, which communicates with the first cylinder, and in which a second piston formed by a needle valve is slidingly mounted, capable of interrupting the communication between the first cylinder and a dispensing nozzle. They finally comprise elastic means, such as a compression spring, which act on the needle valve tending to maintain the latter in a blocking position in which said communication is interrupted. 
         [0006]    Such pumps have the following operating principle: when the first piston is moved, the liquid located in the first cylinder is forced into the second cylinder, in which the pressure increases. The second piston tends to push into its cylinder, compressing the spring. When the pressure of the liquid reaches a high enough value to balance this action, the second piston moves, driving the valve linked to it, so that the cylinders are placed in communication with the dispensing nozzle. 
         [0007]    Such pumps do not comply with the present demands of quality standards since, for example, the liquid product can be polluted through contact with the metal spring that returns the needle valve to blocking position after dispensing the liquid product. 
         [0008]    Furthermore, the doses of liquid product dispensed are often inaccurate, which limits the use of these pumps to the dispensing of certain products. 
         [0009]    Moreover, the designs of these pumps do not allow the pump to be produced in several models capable of dispensing the product with different dose sizes. In fact, the volume of the chamber cannot be changed without changing the dimensions of the pump. Thus, it is necessary to provide specific packaging for each size of pump, which considerably increases the production costs. 
       SUMMARY OF THE INVENTION 
       [0010]    The invention aims to solve these disadvantages. 
         [0011]    It relates to a pump for dispensing a liquid or semi-liquid product, designed to be used, in particular in the pharmaceutical or cosmetic field. The pump comprises needle valve made up of a base topped by a rod, and a dispensing head manually movable on a pump body between an inactive position and a punctual product-dispensing position. The head comprises:
       a first cylinder forming a dosage chamber of the pump, which communicates with an intake tube by means of a check valve, a piston being slidingly mounted in the first cylinder;   a second cylinder in which the needle valve is slidingly mounted, said needle valve forming an exhaust valve;   elastic means for returning the needle to the orifice blocking position.       
 
         [0015]    According to the invention, the dispensing head comprises means for allowing the liquid to pass between the dosage chamber and a second chamber provided at the end of the dispensing head, without the liquid being in contact with the return means. Furthermore, the second cylinder comprises a compartment in which the elastic return means are housed, which is isolated from the second chamber by watertight sealing means, the second chamber communicating with the orifice of the dispensing head. 
         [0016]    According to a first embodiment of the pump according to the invention, the passage means consist of at least one passage channel made at least partially in one wall of the cylinder, one of the ends of the channel opening into the dosage chamber and the other end of the channel opening into the second chamber. 
         [0017]    In the context of one embodiment, the pump can be manufactured such as to ensure that the second chamber has a volume equal to one dose of product. However, this embodiment is only one alternative embodiment of the invention. Also, a pump having a volume equal to less than one dose can also correspond to the pump according to the invention. 
         [0018]    Moreover, it can be provided for the second chamber to be a chamber for chemical or bacteriological treatment of a dose of product. 
         [0019]    According to another alternative embodiment, the return means consist of a compression spring. 
         [0020]    The pump according to the invention advantageously comprises means for assembling and centring this return spring in relation to said needle valve. 
         [0021]    According to yet another alternative embodiment of the pump according to the invention, the watertight sealing means of the compartment consist of a projecting radial ring on an external wall of a base of the needle valve. 
         [0022]    According to yet another alternative embodiment, the pump comprises a conduit for checking the seal between the compartment and the second chamber, the conduit communicating with the cylinder by being made through the wall of the cylinder, and being capable of being connected to pneumatic measurement means. 
         [0023]    According to a further alternative embodiment, it comprises a spring for returning the dispensing head to the inactive position. 
         [0024]    Advantageously, in the context of the latter embodiment, it is provided for the dispensing head to comprise an inner skirt and an outer skirt, between which the second compression spring is placed, the second cylinder being surrounded by the inner skirt of the dispensing head so that the liquid is not in contact with the second spring. 
         [0025]    The chamber has a volume preferably comprised between 30 and 250 μL. 
         [0026]    In an advantageous manner, it is also provided for the pump according to the invention to comprise means for support and attachment on a container of a product to be dispensed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    Further objectives and advantages of the invention will become apparent from the following description made in reference to the appended drawings, wherein: 
           [0028]      FIG. 1  shows, in a side view, a pump according to a first embodiment of the invention; 
           [0029]      FIGS. 2 to 7  show, in a section view, the pump depicted in  FIG. 1  in different steps of activation, as well as the course of the liquid product in said pump in each of these steps. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]    The pump according to the invention as described below is particularly suitable to be used to dispense a liquid or semi-liquid pharmaceutical product in the form of a nose spray. 
         [0031]    It should, however, be understood that a pump according to the invention can have different shapes, and that it can apply to fields other than the pharmaceutical field. In addition, the numbers mentioned in the context of this example are not all limiting. 
         [0032]    Initially, the embodiment of a pump  1  according to the invention is described in reference to  FIG. 1 . Then, the various steps relating to dispensing a dose of product are described in reference to  FIGS. 2 to 7 . 
         [0033]    As shown in  FIG. 1 , the pump  1  comprises needle valve  2  made up of a base  21  topped by a rod  22 , and a dispensing head  4  manually movable on a pump body  10  between an inactive position and a punctual product-dispensing position. 
         [0034]    It also comprises means  3  for support and attachment on a container of a product to be dispensed. 
         [0035]    In a standard manner, the head  4  comprises a first cylinder  41  forming a dosage chamber  7  of the pump, which communicates with an intake tube  42  by means of a check valve  43 , a piston  44  being slidingly mounted in said first cylinder  41 . 
         [0036]    The head  4  also comprises a second cylinder  5  in which the needle valve  2 , forming an exhaust valve, is slidingly mounted, as well as elastic means  6  for returning the needle valve  2  to a position in which it blocks an orifice  45  through which the product is expelled. 
         [0037]    According to the invention, the dispensing head  4  comprises means for allowing the liquid to pass between said dosage chamber  7  and a second chamber  8  provided at the end of the dispensing head  4 , without the liquid being in contact with the return means  6 . 
         [0038]    These passage means consist of at least one passage channel  46  made at least partially in one wall  53  of the cylinder  5  so that one of the ends of the channel  46  opens into the dosage chamber  7  and the other end of the channel opens into the second chamber  8 . 
         [0039]    Furthermore, the second cylinder  5  comprises a compartment  51  in which the elastic return means  6  are housed and which is isolated from the second chamber  8  by watertight sealing means  52 , the second chamber  8  communicating with the orifice  45  of the dispensing head  4 . 
         [0040]    In the context of this embodiment, the volume of the second chamber  8  is less than that of the dosage chamber  7 . 
         [0041]    It is also possible for the second chamber  8  to have a volume equal to one dose of product, and to comprise means for chemical or bacteriological treatment of said dose, for example by contact with agents dispersed in the wall of said chamber. However, in order to facilitate the understanding of the figures, this embodiment is not shown. 
         [0042]    To allow the needle valve  2  to come out of the orifice  45 , and thus allow the product to be dispensed, it is provided for the ratio between the section of the dosage chamber  7  and the second chamber  8  to be comprised between 2 and 10. In the context of this embodiment (shown in  FIG. 1 ) the ratio is 8. 
         [0043]    As can be seen in  FIG. 1 , the means for returning the needle valve to the position in which it blocks the orifice  45  consist of a compression spring  6 . 
         [0044]    According to advantageous characteristics, the pump described here comprises means for assembling and centring the return spring  6  in relation to the needle valve  2 . 
         [0045]    In view of  FIG. 1 , it is understood that these assembly and centring means consist of a lug  23  projecting from the base  21 , around which the spring  6  is engaged. 
         [0046]    Furthermore, the watertight sealing means of said compartment  51  are formed by a projecting radial ring  52  on an external wall of the base  21  of the needle valve  2 . 
         [0047]    The pump  1  according to the invention as shown in the appended figures comprises a conduit  55  for checking the seal between the compartment  51  and the second chamber  8 . 
         [0048]    The conduit  55  communicates with the compartment  51  by being made through the wall of the cylinder  5  and being capable of being connected to pneumatic measurement means. 
         [0049]    These pneumatic measurement means can be, for example, a pressure gauge, checking the internal pressure within the compartment  51 : if the seal between the compartment  51  and the chamber  8  is not perfect, an air leak can appear between the ring  52  and the inner face of the wall  53 . This air leak can be detected by the pressure gauge, which then indicates a pressure drop. 
         [0050]    Furthermore, the conduit  55  has a double function since it allows the release of the air contained in the compartment  51  when the spring  6  is compressed, as shown in  FIG. 4  in particular by an outward arrow S 2 . 
         [0051]    In addition, it is provided to equip the pump  1  with a second compression spring  9  guaranteeing the elastic return of the dispensing head  4  to the inactive position. 
         [0052]    The dispensing head  4  then comprises an inner skirt  47  and an outer skirt  48  ( FIG. 1 ), between which the second spring is placed. 
         [0053]    As shown, the second cylinder  5  is surrounded by the inner skirt  47  of the dispensing head so that the liquid is not in contact with this second spring  9 , which could pollute or contaminate it. 
         [0054]    The liquid product is normally sprayed in doses with volumes comprised between 30 and 250 μL and this is therefore the range of volumes chosen for the dosage chamber  7 . 
         [0055]    The actual design of this pump  1  makes it possible to change the volume of the dosage chamber without having to modify the wrapping or packaging of the bottle equipped with this pump. 
         [0056]    In fact, in relation to  FIG. 1 , it can be easily understood that it suffices merely to change the length of the pump body  10  which encloses the cylinder  41  containing the dosage chamber  7 . Since the pump body is enclosed within the bottle (or container) containing the product, it is not necessary to change the dimensions of the top of the dispensing head  4 . In other words, the part of the pump that tops the means  3  for supporting and attaching it to the container, or bottle, of the product to be dispensed, does not change size and always has the same bulk. 
         [0057]    The pump  1  according to the invention depicted in  FIG. 1  having been entirely described, the various steps of spraying a dose of product are presented below in reference to  FIGS. 2 to 7 . 
         [0058]      FIGS. 2 to 7  show the pump  1  in a section view at different stages of spraying a dose of liquid product, between the moment when the user begins to press the dispensing head  4  and the moment when the dispensing head  4  returns to its inactive position. 
         [0059]      FIG. 2  shows the pump  1  in its initial state, before dispensing a dose of product, and after being primed, which is to say, after having been pressed several times in order to release the air contained in the dosage chamber and replace it with a dose of product to be dispensed. 
         [0060]      FIG. 7  shows the pump  1  in its final state, after dispensing a dose of product. 
         [0061]    It can be seen that the pump  1  shown in  FIG. 2  is identical to that in  FIG. 7 . Also, therefore, it is understood that the pump can be activated again to dispense a second dose of product as soon as the spraying head returns to its initial position. 
         [0062]      FIG. 3  shows the pump  1  at the moment when the user begins to exert pressure P (depicted by an arrow in  FIG. 3 ) on the dispensing head  4 . 
         [0063]    Under the action of this pressure P, the piston  44  compresses the product contained in the dosage chamber  7 . 
         [0064]    The product compressed in the dosage chamber  7  then in turn exerts a pressure on the liquid contained in the passage  46 , and indirectly on the liquid product contained in the second chamber  8 . 
         [0065]    As can be understood from  FIG. 4 , the pressure exerted on the liquid product contained in the second chamber  8  in turn exerts a pressure on the base  21  of the needle valve  2 . 
         [0066]    Also, under the effect of this pressure, the base  21  of the needle valve  2  compresses the spring  6  in the compartment  51 . 
         [0067]    The base  21  of the needle valve being solidly attached to the rod  22  of the needle valve, the latter moves out of the orifice  45  freeing up a passage through which the liquid product is ejected towards the outside of the pump, as shown by the arrow S 1 . 
         [0068]    At the same time, due to the presence of sealing means  52 / 54  between the compartment  51  and the second chamber  8 , the air contained within the compartment  52  is pushed into the conduit  55 , penetrating the space comprised between the inner skirt  47  and the outer skirt  48  of the dispensing head, and is expelled out of the pump following the arrow S 2 . 
         [0069]      FIG. 5  shows the pump  1  with its dispensing head  4  pushed in as far as possible by the user, until its bottom end position. 
         [0070]    When the dispensing head  4  is in its bottom end position, the piston  44  is in its top end position in the first cylinder  41 , and the dosage chamber  7  is penetrated by the end of the piston  44 . 
         [0071]    Also, at the moment when the head  4  is located in its bottom position, the piston  44  ceases to exert pressure on the liquid contained in the chamber or in the passage  46 . 
         [0072]    In addition, the liquid product contained in the second chamber  8  ceases to exert pressure on the base  21  of the needle valve  2 . 
         [0073]    Also, the compression spring  6  extends and causes the needle valve  2  to rise up until the end of the rod  22  blocks the orifice  45  of the dispensing head  4 . The dispensing of the dose of liquid ends in this way. 
         [0074]    When the user stops exerting pressure on the dispensing head  4 , as shown in  FIG. 6 , the compression spring  9  tends to cause the dispensing head  4  to rise back up, exerting a pressure on B, between the inner skirt of the spraying head. 
         [0075]    The dispensing head  4 , solidly attached to the cylinder  41  comprising the dosage chamber, drives the cylinder  41  raising it up to its initial position. 
         [0076]    A depression is thus created in the dosage chamber  7 , which then sucks in the liquid product contained in the intake tube  42 . 
         [0077]    The dispensing head continues to rise under the action of the spring  9  until it reaches the initial top position shown in  FIG. 7 , and the dosage chamber  7  continues to fill under the effect of the depression created in the chamber (suction phenomenon). 
         [0078]    Once the dispensing head  4  reaches its top position, the pump  1  can then be activated again by the user to dispense a new dose of the product. 
         [0079]    The preceding description discloses the specific characteristics of the pump, allowing the product never to be in contact with contaminating agents, in particular relating to the elastic means for returning the needle valve to the blocking position, and to the elastic return means of the dispensing head. 
         [0080]    Also, it is understood how the pump  1  according to the invention is designed to limit the expense involved in wrapping and packing the bottle on which it is mounted. 
         [0081]    It should, however, be understood that the pump according to the invention is not limited to the above description, shown in  FIGS. 1 to 7 , and that, on the contrary, it extends to all alternative embodiments that fulfil the main characteristics of the same.