EP1249278A1

EP1249278A1 - Dispensing pump

Info

Publication number: EP1249278A1
Application number: EP20010830249
Authority: EP
Inventors: Stefano Santagiuliana
Original assignee: Taplast SRL
Current assignee: Taplast SRL
Priority date: 2001-04-10
Filing date: 2001-04-10
Publication date: 2002-10-16
Also published as: AU2002253430A1; DE60202359D1; WO2002083318A2; DE60202359T2; EP1379336A2; WO2002083318A3; EP1379336B1; ES2235032T3

Abstract

The dispensing pump (1) comprises a hollow body (3) defining a suction and compression chamber (4) for fluid (F) to be delivered, communicating with the inner room of container (C) through a suction duct (4a). A first tight piston (5) is slidingly coupled to the hollow body and is slidingly and coaxially coupled to an end (6) of a second piston (7), internally provided a tubular chamber (8). Passage of fluid through a hole (13) is intercepted through a first shaped rim belonging to the first piston and sealingly coupled according to the mutual position of the two pistons with a corresponding second shaped rim of the second piston. There are at least two discreet annular sealing zones between the two rims.

Description

The present invention relates to a delivery pump to be coupled to the neck of a container, particularly adapted to deliver fluids such as food, liquid detergents, creams or perfumes.
It is well known that hygienic and practical requirements led to a considerable spread on the market of containers for fluids provided with delivery devices to be manually actuated by the user.
The known delivery pumps generally comprise a hollow body defining a suction and compression chamber for the fluid to be delivered, communicating with the inner room of the container through a suction duct.
A first tight piston is slidingly coupled to the hollow body and is also slidingly and coaxially coupled to one end of a second piston internally provided with a tubular chamber.
More particularly the first piston slides inside a seat made at the end of the second piston, moving from a top dead center to a bottom dead center defined by an annular boss preventing the mutual decoupling of both pistons.
The tubular chamber communicates with outside through a delivery duct and with the suction and compression chamber through one or more holes made on the second piston at said seat.
Said holes are intercepted by a first annular rim belonging to the first piston and coupled to a corresponding second annular rim belonging to the second piston.
More particularly each annular rim consists of a couple of frustum conical annular surfaces which define a single annular sealing zone allowing to open or close the delivery duct according to the mutual position of the two pistons.
Valve means generally consisting of metal balls arranged between the suction and compression chamber and the inner room of the container, regulate inflow and outflow of fluid in said chamber.
Finally elastic means, generally consisting of helical springs arranged between the hollow body and the pistons, ensure return of said piston to the rest position at the end of a delivery operation.
In operation the user acting on the piston loads the elastic means and compresses the liquid contained in the suction and compression chamber at the same time moving the first piston to its top dead center so as to push away the annular rims allowing outflow of the liquid to the delivery duct.
When the tight piston reaches the bottom of the suction and compression chamber, it is released by the user so as to allow the elastic means to return it to the start rest position.
The elastic return of the piston generates a depression inside the chamber opening the liquid suction ducts and returning the first piston to its bottom dead center so as to close the delivery duct and allowing inflow of liquid inside the chamber thus preparing the pump for the subsequent delivery.
Efficiency of suction and therefore proper operation of the pump in the subsequent delivery phase, is determined by the seal effected by the couple of annular rims and the characteristics of the material used for their manufacture.
A first limit of the above mentioned devices consists in that said pumps have a limited suction efficiency for the liquid from the container.
This is substantially due in some devices to the damage underwent by the first piston during the pump assembling stage.
Indeed in these devices coupling of the two pistons is made by forcing coaxially one piston against the other thus obtaining a plastic deformation to step over the annular boss and lodge the first piston inside its seat.
From the foregoing it is clear that the two pistons undergo a mechanical stress that may even damage them permanently, compromising the proper operation of the pump.
In order to avoid said mechanical stress, some known devices are provided with an annular boss which is not made on the second piston but on a plug that is being applied after coupling of the pistons.
However also these devices show with time a reduction of the suction efficiency.
This is substantially due to the fact that the delivery pump in its rest position has the elastic means keeping the two frustum conical annular surfaces compressed one against the other, so as to cause a progressive burr of said surfaces.
In addition to this drawback the assembled pump in the rest condition during transportation and stockage, is subject to considerable thermal stress increasing and accelerating deterioration of the sealing surfaces.
Object of the present invention is to overcome the above mentioned limits and drawbacks.
More particularly a first object is to provide a delivery pump having a greater suction efficiency relative to the known pumps.
Another object is to provide a pump keeping the suction efficiency substantially constant with time.
A further object is to provide a pump which is tolerant to thermal stress which undergoes during the transportation and stockage stages.
Another object is to provide a pump that at the end of its use can be immediately and fully recycled without any previous disassembling operation to separate materials which are different and incompatible to one another.
A further object is to provide a pump which is particularly easy and reliable in use.
A last but not least object is to provide a pump which is particularly cheap, easy to be produced and assembled being suitable for mass production.
Said objects are attained by a delivery pump for containers of fluids to be delivered that according to the main claim comprises:

at least a hollow body defining a fluid suction and compression chamber communicating with the inner room of said container;
a first tight piston sliding in said at least one hollow body, slidingly coupled to a second piston internally provided with at least a tubular chamber communicating with outside through at least a fluid delivery duct and with said suction and compression chamber through at least a hole made in said second piston;
at least a first shaped annular rim belonging to said first piston, to be coupled with at least a corresponding second shaped rim belonging to said second piston;
elastic means arranged between at least one of said pistons and said at least one hollow body;
valve means arranged between said suction and compression chamber and the inner room of said container;

Surprisingly this allows to obtain delivery pumps having a greater suction efficiency relative to the traditional pumps of this kind and substantially constant with time.
Also surprisingly conducted tests show that the pump is tolerant to long periods of outage.
The foregoing objects and advantages will be better understood by reading the following description of a preferred embodiment given as an illustrative but non-limiting example and shown in the accompanying sheets of drawings in which:

Fig. 1 is a sectional view of the delivery pump of the invention, applied to a container;
Fig. 2 is an enlarged view of part of the pump of Fig. 1 in an operative condition;
Fig. 3 shows the part of Fig. 2 in another operative condition;
Figs. 4 to 8 are sectional views each showing a different constructional variation of some elements of the pump of Fig. 1; and
Figs. 9 and 10 are sectional views each showing a different operative stage of the pump of the invention.

The delivery pump of the present invention is shown in Fig. 1 where it is indicated generally with reference numeral 1, and is provided with means 2 for the movable coupling to the neck O of a container C for the fluid F to be delivered.
Said pump comprises a hollow body 3 defining a suction and compression chamber 4 for the fluid F to be delivered, communicating with the inner room of container C through a suction duct 4a.
A first tight piston 5 is slidingly coupled to the hollow body 3 and is slidingly and coaxially coupled to an end 6 of a second piston 7, internally provided with a tubular chamber 8.
More particularly the first piston 5 moves relative to the second piston 7, as shown in detail in the enlargements of Figs. 2 and 3, from a bottom dead center 10 to a top dead center 11, the movement being guided by the sliding edge 9.
The tubular chamber 8 communicates with outside through a delivery duct 12 and with the suction and compression chamber 4 through a hole 13 made at the seat 9 in the second piston 7.
Passage of fluid F through the hole 13 is intercepted through a first shaped annular rim 14 that can be seen in detail in Fig. 3, belonging to the first piston 5 and sealingly coupled according to the mutual position of the two pistons 5, 7, with a corresponding second shaped rim 15 belonging to the second piston 7.
Elastic means, generally indicated with numeral 16 in Fig. 1 and in this embodiment consisting of a bellows spring 40 totally made of plastic material and provided with a perimetral spiral rib 41, are arranged between the two pistons 5,7 and the hollow body 3 so as to cause the movement of said pistons 5,7 inside the chamber 4 elastically yielding.
Valve means generally indicated with numeral 17, in this embodiment consisting of a ball 42 made of plastic material and arranged in a corresponding seat made on the edge of the suction and compression chamber 4, are arranged between the suction and compression chamber 4 and the inner room of container C. These valve means regulate inflow of fluid F from the inner room of container C to the chamber 4 and outflow to the delivery duct 12.
The invention provides that between the first shaped rim 14 and the second shaped rim 15 there are at least two discreet annular sealing zones 18, 19 shown in Figs. 2 and 3.
More particularly the first shaped rim 14 consists of a first projecting rim while the second shaped rim 15 consists of a concave annular seat receiving said projecting rim.
Each annular zone 18, 19 has a couple of surfaces 18a, 18b, 19a, 19b shown in detail in Fig. 3, each belonging to a corresponding shaped annular rim 14, 15, in this embodiment consisting of plain surfaces belonging to a mixtilinear contour.
More particularly when the first piston 5 is at its bottom dead center 10, surfaces 18a, 18b, 19a, 19b are in mutual contact along at least one line, so as to allow tightness and consequent cut off of the hole 13.
A first constructional modification shown in detail in Figs. 4 and 5 is different from the preceding embodiment because the sealing surfaces have a curved contour. More particularly in Fig. 4 each surface 20a, 20b and 21a, 21b consists of a stretch of parabole.
The variation of Fig. 5 provides that surfaces 22a, 22b and 23a, 23b belong to a portion of sphere.
Alternatively the two surfaces may indifferently have the one a curved shape and the other a rectilinear shape has shown in Figs. 6 and 7.
A further constructional variation shown in detail in Fig. 8 is different from the preceding ones because the sealing surfaces 24a, 24b, 25a, 25b, 26a, 26b and 27a, 27b define four different annular sealing zones instead of two zones as in the preceding embodiments.
In this regard it is important to note that the increase of the number of sealing surfaces corresponds to a greater suction efficiency of the pump.
Therefore the delivery pump 1 is fully made of plastic material, so that it can be immediately and totally recycled.
In this connection it is to be pointed out that the plastic material used to make the first piston 5 has special mechanical features allowing to obtain an optimal seal.
In operation the user acting on piston 7 loads the elastic means 16 and compresses fluid F contained in the suction and compression chamber 4.
The first piston 5 moves then to its top dead center 11 as shown in Fig. 9, so as to move away the annular rims 14, 15 and allow outflow of fluid F to the delivery duct 12 along the path indicated with numeral 50.
When the piston 7 reaches the bottom of the suction and compression chamber 4 as shown in Fig. 10, it is released by the user so as to cause the elastic means 16 to return it to the start rest position shown in Fig. 1.
The elastic return of piston 7 generates a depression inside the chamber 4 opening the suction ducts 4a for the fluid F. At the same time the first piston 5 returns to its bottom dead center 10 closing the delivery duct 12 thus allowing inflow of fluid F inside the chamber 4 and preparing said pump 1 to the next delivery.
It is important to note that the proposed solution may be applied to any kind of delivery pump whether in the configuration as simple distributor, as atomizer or even as foamer.
From the foregoing it is clear that the illustrated delivery pump fully attains the above mentioned objects.
Although the invention was described with reference to the accompanying sheets of drawings, in the production stage it may undergo constructional modifications falling however within the same inventive principle set forth in the appended claims and therefore within the scope protected by the patent.

Claims

A delivery pump (1) for containers (C) of fluids (F) to be delivered comprising:

at least a hollow body (3) defining a suction and compression chamber (4) for the fluid (F), communicating with the inner room of said container (C);

a first tight piston (5) sliding in said at least a hollow body (3), slidingly coupled to a second piston (7) internally provided with at least a tubular chamber (8) communicating with outside through at least a delivery duct (12) for said fluid (F) and with said suction and compression chamber (4) through at least a hole (13) made in said second piston (7);

at least a first shaped annular rim (14) belonging to said first piston (5) to be coupled with at least a corresponding second shaped rim (15) belonging to said second piston (7);

elastic means (16) arranged between at least one of said pistons (5, 7) and said at least a hollow body (3);

valve means (17) arranged between said suction and compression chamber (4) and the inner room of said container (C);

characterized in that between said at least one first shaped rim (14) and said at least one second shaped rim (15) there are at least two discreet annular sealing zones (18, 19).
The pump (1) according to claim 1) characterized in that each of said zones (18, 19) is provided with at least a first surface (18a, 19a, 20a, 21a, 22a, 23a, 24a, 25a, 26a and 27a) belonging to said at least one first shaped annular rim (14) and at least a second surface (18b, 19b, 20b, 21b, 22b, 23b, 24b, 25b, 26b and 27b) belonging to said at least one second shaped rim (15), in mutual contact at at least one point.
The pump (1) according to claim 2) characterized in that said first surfaces (18a, 19a, 24a, 25a, 26a, 27a) and said second surfaces (18b, 19b, 24b, 25b, 26b, 27b) are plain surface.
The pump (1) according to claim 2) characterized in that said first surfaces (20a, 21a, 22a, 23a) and said second surfaces (20b, 21b, 22b, 23b) belong each to a curved surfaces.
The pump (1) according to claim 2) characterized in that said first surface belongs to a plain surface and said second surface belongs to a curved surface.
The pump (1) according to claim 2) characterized in that said first surface belongs to a curved surface and said second surface belongs to a plain surface.
The pump (1) according to claim 2) or 4) or 5) characterized in that at least one of said curved surfaces is a parabole.
The pump (1) according to claim 2) or 4) or 5) characterized in that at least one of said curves is a circular section of a sphere.
The pump (1) according to claim 1) characterized in that said first rim (14) is a projecting rim and said at least one second shaped rim (15) is a seat.
The pump (1) according to claim 1) characterized in that said at least one first rim (14) is an annular seat and said at one second rim (15) is a projecting rim.
The pump (1) according to any of the preceding claims characterized in that said elastic means (16) consist of a bellows spring (40) made of plastic material.
The pump (1) according to claim 11) characterized in that said bellows spring (40) is provided with at least a perimetral spiral rib (41).
The pump (1) according to any of the preceding claims characterized in that said valve means (17) consist of a ball (42) made of plastic material.