Reduced-height precompression pump

ES 2 258 167 T3

DESCRIPTION

Low head pre-compression pump.

Field of the invention

The invention relates to a pre-compression pump comprising:

- a cylinder defining a pump body and inside which a pumping chamber is arranged,

- an inlet valve arranged at the bottom of the cylinder,

- a piston, the piston having an outwardly widening lower lip seal, the outwardly widening lower lip seal being suitable for sliding fit inside the cylinder, and a widening lip seal towards the interior bordering a central hole of the piston,

- a pumping rod, suitable to slide into the central hole, the pumping rod being hollow and having a communication conduit inside that is suitable for communicating the pumping chamber with the exterior,

- a fixing device suitable for fixing the cylinder to a container, the fixing device defining an upper retention cover,

- a first elastic element housed in the cylinder and a second elastic element.

These pre-compression pumps allow spraying with pre-compression of liquids contained in a container.

State of the art

Pre-compression pumps are known, used to spray all kinds of liquids, for example perfumery products, cosmetics, cleaning products, pharmaceutical products, etc.

In general, the precompression device is a device that guarantees that the liquid exits to the outside only when it is already subjected to a certain minimum pressure inside the pumping chamber. In this way, a higher pressure liquid outlet is ensured, which, for example, makes it possible to improve its subsequent spraying.

The technique of pre-compression spraying is known, and various pre-compression pumps are known which are suitable for performing pre-compression spraying. For example in EP 737 519 A2, a spray pump with a pre-compression device is disclosed. Also, in US 4,856,677, US 4,941,595 and US 5,234,135, other spray pumps including pre-compression devices are described.

A spray pump according to the preamble of claim 1 is disclosed in US 6,036,059.

In general, pre-compression pumps should be small in size. This requirement is particularly important in the case of its use in cosmetic or perfumery products, since in these cases it is desired to minimize the aesthetic impact caused by the pumping mechanism. In particular, it is important to reduce the height of the assembly. Logically, any design that allows the manufacture of a low head pre-compression pump must always be compatible with the usual requirements in this type of product, such as low production cost, low number of parts to be assembled, high spray reliability, etc. .

Summary of the invention

The object of the invention is to provide a low head pre-compression pump. In particular it is intended to provide a pump similar to that described in EP 737 519, but with a lower head. This objective is achieved by means of a pre-compression pump of the type indicated at the beginning, characterized in that said second elastic element has an upper support point applied directly on said pumping rod, where said upper support point is above said upper retention cover. .

Indeed, the second elastic element is responsible for the precompression force on the piston, its fulcrum being the pumping rod. By allowing the upper support point to be above the upper retention cover, the height of the assembly can be reduced, since the existing space above the upper retention cover is used, said space usually remaining covered by a plug spray and in which normally only the pump stem extends.

Preferably the piston is suitable to move between an upper position (or extended position) and a lower position (or retracted position), and has an upper lip seal that widens outwards, arranged above the lower lip seal that widens outwards, and the cylinder has a ventilation hole located at a height such that it remains between the upper and lower lip seals that widen outwards when the piston is in the upper position, and such that it communicates the interior of the container with the atmosphere when the piston is in the lower position. Indeed, the pre-compression pump must have an air passage that allows the pumped liquid to be replaced by air inside the container. For said ventilation, a lateral hole is preferably provided between both lip seals that widen outwards, as indicated above. When the pump is in the "idle" position, that is, with the pump rod fully extended upwards, the vent hole is housed between both lip seals that widen outwards. In this way no fluid communication is established with the outside, so that the pump is watertight. As the pump rod descends during a pumping motion there comes a time when the outwardly widening upper lip seal moves below the vent hole. At this time the vent hole allows fluid communication to be established between the inside of the container and the outside, usually through free spaces in the vicinity of the pumping rod.

Preferably the pre-compression pump pre2

ES 2 258 167 T3 provides a retention device arranged next to the cylinder and the fixing device, the retention device being suitable to be engaged in the cylinder so that the piston is retained by the retention device inside the cylinder. Indeed, pre-compression pumps usually have a series of common elements, generally standardized, which comprise most of the functional elements of the pump, and which are housed inside the cylinder, such as the inlet valve, the piston, etc. the pump rod, the elastic elements, etc. On the other hand, they have elements that are different from each other depending on the specific application of the pump. Generally these elements are the spray cap and the fixing device. In this sense, it may be interesting that the manufacturing process can be carried out in two stages: a first stage in which the common elements are assembled, and a second stage in which the pump is “customized” by adding the specific elements for a specific application. For this phased manufacturing system to be viable from a practical point of view, it is convenient that the set of common elements is assembled in such a way that it can be manipulated without disassembling. In this sense, it is advantageous to have a retention device that can be snapped onto the cylinder once the remaining elements are already inserted into said cylinder. In this way the assembly can be manipulated without the various components loosening from the cylinder. Preferably the retention device serves as a fulcrum for the piston, so that the piston is in contact with the retention device due to the force exerted by the first elastic element on the piston. For its part, the piston retains the pumping rod, preventing the pumping rod from fully exiting the cylinder. The assembly thus assembled can be manipulated and stored, so that the second assembly stage can be carried out independently, both in time and in place. As will be seen later, in certain cases it may be advantageous for the pumping rod to be made up of two parts: the pumping rod itself and a stop that is attached to the lower end of the pumping rod. In this case it is possible for the piston to retain the pump rod by engaging the stop. It should therefore be understood in this case that the stop is part of the pump rod.

As already indicated above, advantageously the retention device has a shoulder on which the piston rests when it is in the upper position (that is, in the extended position). In a preferred embodiment of the invention, the height between the shoulder and the bottom of the cylinder determines the volume of the pumping chamber. In this way, it is possible to provide pumps with different pumping capacities by changing a single part: the retention device.

Advantageously, the second elastic element is made of the same material as the pump rod and is connected to the pump rod in such a way that they form a single piece. In this way it is possible to eliminate one of the components of the pump in the assembly stage, since the second elastic element and the pumping rod are a single piece. Usually this piece is made of a plastic material and is usually manufactured by injection. In this way, apart from reducing the assembly cost of the assembly, the cost of manufacturing the components can also be reduced, since the second elastic element and the pumping rod are obtained from a single manufacturing process.

Alternatively, the second elastic element can be of any other type, such as a conventional helical spring, made of metallic material. The metallic coil springs have, for their part, a series of well-known but also important advantages, such as the maintenance of elastic properties over time, the possibility of making significant efforts compared to their size, the ease of modify the effort that the spring must make by modifying its geometry, etc.

Preferably, the pumping rod has an annular projection whose outer edge is extended by a cylindrical surface parallel to the pumping rod, the cylindrical surface having grooves such that allow the cylindrical surface to be compressed along the longitudinal axis in a manner reversible, in such a way that the cylindrical surface defines the second elastic element. The annular projection thus defines the upper bearing point of the second elastic element. The cylindrical surface extends from this annular projection in such a way as to form a sleeve or envelope for the pumping rod. Between the cylindrical surface and the pump rod there is a hollow space which is large enough to ensure that the cylindrical surface can move with respect to the longitudinal axis without rubbing the pump rod. The opposite end of the cylindrical surface rests on the piston. The presence of grooves in the cylindrical surface causes that when the cylindrical surface is subjected to a compression along the longitudinal axis, said cylindrical surface collapses reducing its length. This collapse is however reversible, thanks to the elastic properties of the plastic material used in its manufacture. Therefore the cylindrical surface can exert a force along the longitudinal axis in a manner similar to a conventional coil spring.

Preferably, the grooves are arranged in a plurality of planes perpendicular to the longitudinal axis, in which between each pair of grooves in the same plane there is provided a joint zone comprised in the same plane, each joint zone of a given plane being interposed between two grooves of the planes adjacent to the determined plane. Advantageously, two grooves are provided in each of the perpendicular planes. The grooves are advantageously much larger than the joining zones so that in a plane perpendicular to the longitudinal axis containing the grooves the greater part of the cylindrical surface is made up of grooves, and only small sections of material are provided that form the zones of Union. In the perpendicular plane adjacent to a given plane, the grooves are offset at an angle so that the joint area faces a groove. In this way, by exerting a compressive force on the cylindrical surface, the joint area moves towards the grooves that surround it, thus generating an elastic deformation.

ES 2 258 167 T3

Brief description of the drawings

Other advantages and characteristics of the invention will become more apparent from the following description, in which, without any limitation, preferred embodiments of the invention are described, with reference to the attached drawings, in which :

Figure 1 is a longitudinal sectional view of a first embodiment of a pre-compression pump according to the invention, with the pump rod fully extended.

Figure 2 is a longitudinal sectional view of the pump of Figure 1, with the pump rod partially retracted and rotated 90 °.

Figure 3 is a longitudinal sectional view of the pump of Figure 1, with the pump rod fully retracted.

Figures 4, 5 and 6 correspond to Figures 1, 2 and 3 of a second embodiment of a pre-compression pump according to the invention.

Figure 7 is a longitudinal sectional view of a third embodiment of a pre-compression pump according to the invention, with the pump rod fully extended.

Figure 8 is a longitudinal sectional view of a pump rod according to the invention.

Figure 9 is a longitudinal sectional view of the pump rod of Figure 8, rotated 90 °.

Figure 10 is a perspective view of the pump rod of Figure 8.

Figure 11 is a longitudinal sectional view of a fourth embodiment of a pre-compression pump according to the invention, with the pump rod of Figure 8 fully extended.

Figure 12 is a longitudinal sectional view of the pump of Figure 11, with the pump rod fully retracted and rotated 90 °.

Figures 13 and 14, Figure 13 fully corresponds to Figure 11, and is represented again to facilitate comparison with the pump of Figure 14, which has a longer retention device.

Detailed description of some embodiments of the invention

Figures 1 to 3 show a first embodiment of a pre-compression pump according to the invention. The pump comprises a cylinder 1 defining a pump body. Inside the cylinder 1 a pumping chamber 3 is defined. The cylinder 1 has an inlet valve 5 arranged at the bottom of said cylinder 1. The upper end of the cylinder 1 is open. The inlet valve 5 can be of any known type such as, for example, a ball valve as represented in the figures. The inlet valve 5 has a ball retention system to prevent the ball from slipping out of its housing. These restraint systems are conventional and have not been shown in all the figures. An example of these can be seen in Figures 11 to 14.

The pumping chamber 3 is closed, with respect to its upper part, by a piston 7. The piston 7 has an outwardly widening lower lip seal 9 that runs along the inner surface of the cylinder 1 when the piston 7 is displaced. along the longitudinal axis 11 defined by cylinder 1. The piston 7 has an outwardly widening upper lip seal 13, which is separated from the outwardly widening lower lip seal 9 by a distance such that when the piston 7 is in its extended position, between the two lip seals that widen outward 9 and 13 remains a vent hole 15.

The piston 7 has a central bore 17 and an inwardly widening lip seal 19 which borders the central bore 17. A pump rod 21 passes through the central bore 17. The pump rod 21 can be displaced along of the longitudinal axis 11 in the longitudinal direction of the central hole 17. The pumping rod 21 is substantially a tube, the interior of which defines a communication conduit 23 that is suitable for communicating the pumping chamber 3 with the outside or, more specifically with a plug 25 that includes a spraying device 27. The pumping rod 21 in turn defines a longitudinal axis that is coincident with the longitudinal axis 11 defined by the cylinder 1. At the lower end of the pump rod 21 there is a stop 29. This stop 29 can be mounted on the pump rod 21 in various ways, such as by friction, by snapping, or by a combination of both. Figures 1 to 7 show stops 29 fixed solely by friction, while in Figures 8, 9 and 11 to 14 stops 29 are shown which are fixed by friction and which, simultaneously, have a snapping device. Obviously, it would be possible to carry out other alternatives, such as, for example, fixing the stop 29 only by snapping. The part of the stop 29 that is housed inside the pumping rod 21 is flattened, so that it does not occupy the entire communication conduit 23, thus allowing the passage of the pumped fluid. The protruding part of the stop 29 has an approximate shape of a cup with a larger diameter than the pump rod 21. In this way, the lip seal that widens towards the interior 19 of the piston 7 can abut the bowl, thus preventing the pumping rod 21 from completely coming out of the piston 7. In addition, the hermetic seal between the piston can thus be carried out. 7 and the assembly formed by the pumping rod 21 and the stop 29, the communication conduit 23 being closed.

A first helical spring defines a first elastic element 31 that bears, at one end, against the bottom of cylinder 1 and at the other end on the stopper cup 29. This first helical spring tends to move the assembly formed by the rod of pump 21, stop 29 and piston 7 towards their extended position, generally out of the cylinder

1.

The upper end of cylinder 1 is open. Through said upper end, the various common components that make up the precompression pump can be introduced into the cylinder 1: the ball of the inlet valve 5, the first helical spring and the assembly formed by the pumping rod 21, the stop 29 and piston 7. A retaining device 33 is then inserted which is retained at the upper end of cylinder 1, for example by means of a snapping mechanism. The retention device 33 has a shoulder 35 on which the piston 7 rests, which is propelled outwards due to the force exerted by the first helical spring. This prevents components from falling out.

ES 2 258 167 T3 common of the pre-compression pump and the assembly thus assembled can be handled and stored without problems.

Furthermore, the retention device 33 allows the manufacture of pre-compression pumps with various pumping capacities, in which all the elements are common except for said retention device 33. Indeed, by manufacturing a retention device 33 that has a step 35 closer to the bottom of the cylinder 1, it is possible to obtain a pre-compression pump with a lower pumping capacity, since the piston 7, when in its extreme position higher, it will define a smaller volume of the pumping chamber 3 and, therefore, the amount of pumped liquid will be less.

At the upper end of the pump rod 21 is mounted a cap 25 having a spray device 27. Both the cap 25 and the spray device 27 are independent of the present invention, so they can be any.

For fixing the pre-compression pump to a container containing the liquid to be pumped, a fixing device 37 is provided. Various fixing devices 37 compatible with the present invention are possible. For example, a metal splint may be used, which has an upper retention cover 39 that rests on the upper end of cylinder 1, for example as shown in Figures 1 to 3, 7, and 11 to 14. Another possible fixing device 37 is a device such as that represented in Figures 4 to 6, and which is described in documents ES P9900578 and ES P200000557. This fixing device 37 also has an upper retention cover 39 which rests on the upper end of cylinder 1. The fixing devices 37 also have a horizontal closing surface 41 which is the one applied to the upper edge of the container, possibly separated from said upper edge of the container by a sealing gasket 43.

In the case of using fixation devices 37 such as those described in documents ES P9900578 and ES P200000557, preferably a capsule 45 will be used as described in document ES P200100471.

To achieve the pre-compression effect, it is necessary that the liquid contained in the pumping chamber 3 is expelled to the outside only when a certain minimum pressure is reached. For this, a second elastic element 47 is provided which forces the piston 7 towards the pumping chamber 3. In this way the piston 7 increases the pressure exerted by the liquid contained in the pumping chamber 3 and only when said liquid reaches a certain minimum pressure, the resulting force will be able to overcome the force of the second elastic element 47, moving the piston 7 upwards and allowing the liquid contained in the pumping chamber 3 to move towards the communication conduit 23 and from the communication conduit 23 to the outside through the cap 25 and the spraying device 27.

The second elastic element 47 can be a conventional helical spring, as shown in figure 7. The upper bearing point 49 of the second elastic element 47 is applied directly on the pumping rod 21 and is above the upper cover. retention 39. In this way it is possible to reduce the height of the assembly.

Alternatively the second elastic element 47 is of the same material as the pump rod 21 and is attached to the pump rod 21 in such a way that they form a single piece. The assembly can be obtained by plastic injection, so that a single physical piece simultaneously performs the functions of the pumping rod 21 and the second elastic element 47. An example of this second elastic element 47 can be seen in Figures 1 to 6 and 11 to 14 and, in greater detail in Figures 8 to 10. In the examples indicated above, it can be seen that the pumping rod 21 has an annular projection. 51 whose outer edge is extended by a cylindrical surface 53 parallel to the pump rod 21. The cylindrical surface 53 forms a type of sleeve or envelope around the body of the pump rod 21. This cylindrical surface 53 has grooves 55 paired with each other and separated from each other by two joining zones 57. Each pair of grooves 55 with their respective joining zones 57 define a "level" of the cylindrical surface 53. At the next "level" "There are again two grooves 55 with two joining areas 57. However, the grooves of the next level are offset from those of the previous level so that the joining areas 57 of a given level are sandwiched between the grooves 55 of the adjacent levels.

Advantageously, the lower end of the second elastic element 47 bears directly on the piston 7. In this way, the force of the second elastic element 47 is transmitted directly to the piston 7, which is actually the one that must be subjected to the elastic force.

The operation of the pre-compression pump is as follows. Starting from an inactive position, in which the pump rod 21 is in its upper or extended position, and which corresponds to Figures 1, 4, 7, 11 and 13, the movement of the pump rod 21 is started downwards. The liquid contained inside the pumping chamber 3 is compressed so that its pressure increases rapidly. If the pump rod 21 continues to descend, the piston 7 already experiences an upward force, due to the liquid under pressure, which overcomes the force of the second elastic element 47, so that the piston 7 (specifically the lip seal that widens towards the inside 19) stops resting against the bowl (on its internal conical surface) of the stopper 29 and allows the liquid to move towards the communication conduit 23. When the force that pushes the pump rod 21 downwards ceases, the first elastic element 31 pushes the whole assembly up again. The second elastic element 47 pushes the piston 7 towards the bowl thus closing the passage to the communication duct 23. This causes a depression in the pumping chamber 3 which forces the opening of the inlet valve 5.

In the event that the pumping chamber 3 is filled with air, said air can be bled since the separation of the piston 7 from the bowl can be mechanically forced at the end of the stroke of the pumping rod 21 (see Figures 2, 3 and 5, 6).