EP1867399A2

EP1867399A2 - An injector for viscous fluids

Info

Publication number: EP1867399A2
Application number: EP07075436A
Authority: EP
Inventors: Mario Laroma Iezzi
Original assignee: Kemac SpA
Current assignee: Kemac SpA
Priority date: 2006-06-16
Filing date: 2007-06-04
Publication date: 2007-12-19
Also published as: EP1867399A3; CN101088626A; ITMO20060197A1

Abstract

An injector for viscous fluids, comprising: a hollow body (2), provided with an internal chamber (3) for containing a determined quantity of fluid, and an injection hole (4), which places the internal chamber (3) in connection with the outside of the hollow body (2); a piston (5), sealedly mobile in the internal chamber (3), between a first position, in which the internal chamber assumes a first volume, and a second position, in which the internal chamber assumes a second volume, which is smaller than the first volume. The piston (5) is predisposed to assume a third position in which the internal chamber (3) assumes a smaller volume with respect to the volume assumed thereby in the second position of the piston (5).

Description

The invention relates to an injector for viscous fluids.
The invention also relates to a device for depositing a matrix of fluid points on a surface.
The invention relates in particular to realising mosaic tiles, i.e. tiles formed by an ordered matrix of ceramic tesserae joined up to one another.
The grout between the ceramic tesserae is generally constituted by points of glue, each or which is arranged between two tesserae located side-by-side such as to adhere to both tesserae.
The depositing of the points of grout is done using a tool essentially constituted by a plate provided with a series of projecting elements. The tool is partially immersed in a recipient containing the grout in order that the projecting elements are wetted by the grout. The grout adheres to the projecting elements in quantities which depend in particular on the level of immersion of the projecting elements and the viscosity of the grout itself.
Following the immersion in the grout, the tool is placed in contact with a support surface in order that the projecting elements, on entering into contact with the surface, deposit a point of grout thereon.
The ceramic tesserae are then positioned on the support surface according to an ordered matrix in which pairs of tesserae placed side-by-side are arranged overlapping points of grout in such a way as to partially overlie them.
The tool used for depositing the points of grout on the support surface for the ceramic tesserae exhibits some drawbacks.
Firstly, it does not enable an accurate control to be made of the quantity of grout deposited at each point. The quantity depends in particular on the nature and viscosity of the grout, the viscosity being further dependent on the environmental conditions, such as temperature and humidity, which are variable over time.
Further, the tool tends to get covered in grout, in the sense that the grout solidifies on the projecting elements, which once more hampers the control of the quantity of grout deposited at each point.
The aim of the present invention is to provide a device which enables the above-described drawbacks to be obviated. The aim is attained by a device for depositing a matrix of points of fluid on a surface comprising a plurality of injectors for viscous fluids of the present invention.
An advantage of the device is that it enables a precise and reliable control to be made of the quantity of grout which is deposited at each point.
A further advantage of the device is that it remains substantially clean, preventing the formation of deposits or accumulations of grout.
Further characteristics and advantages of the invention will better emerge from the detailed description made herein below, with reference to the figures of the drawings, which are given purely by way of non-limiting example, and in which:

figures 1, 2, 3, 4 are views in section of the injector of the present invention, illustrated in four different operating configurations;
figure 5 is a view in section of the device of the present invention, comprising a plurality of injectors of the present invention;
figure 6 is a plan view of the device of figure 5.

With reference to the figures of the drawings, the injector of the present invention comprises a hollow body 2, provided with an internal chamber 3, predisposed for containing a determined quantity of fluid, and an injection hole 4 which places the internal chamber 3 in communication with the outside of the hollow body 2. A piston 5 is sealedly mobile in the internal chamber 3 between a first position, in which the internal chamber 3 assumes a first volume, and a second position, in which the internal chamber 3 assumes a second volume, smaller than the first volume.
During the displacement of the piston 5 from the first to the second position, the volume of the internal chamber 3 progressively diminishes. Consequently the fluid contained in the internal chamber 3 is expelled by the hollow body 2 through the injection hole 4. On the contrary, during the displacement from the second to the first position of the piston 5, the volume of the internal chamber 3 increases. Consequently fluid external of the hollow body 2 can be aspirated into the internal chamber 3 through the injection hole in a quantity which corresponds to the change in volume of the internal chamber 3 during the displacement of the piston 5 from the second to the first position. This enables a very precise control to be made of both the quantity of fluid which is aspirated internally of the hollow body 2 and, obviously, the quantity of fluid which is subsequently injected.
The piston 5 is advantageously predisposed to assume a third position in which the internal chamber 3 assumes a smaller volume with respect to the volume assumed at the second position of the piston 5. The possibility for the piston 5 to assume this third position offers the important advantage of enabling a substantially complete expulsion of the fluid present internally of the internal chamber 3. The maximum quantity of fluid which can be aspirated into the internal chamber 3 corresponds to the variation of volume of the chamber 3 itself as it grows from the first to the second positions of the piston 5, while the change in volume between the first and the third positions of the piston 5 is greater than the change in volume thereof between the first and the second positions of the piston 5. The change in volume of the internal chamber 3 between the first and the third positions is therefore greater than a change which would be necessary for determining the complete expulsion of the fluid present internally of the chamber.
The hollow body 2 preferably exhibits a tapered end portion which exhibits an apex 2a at which the injection hole 4 opens. At the tapered end portion the injector can be immersed in a mass of fluid in order to aspirate the predetermined quantity by shifting the piston 5 from the second position into the first position. The tapered shape facilitates the running of the fluid when the injector is raised, such as to prevent formation of accumulations of fluid on the external surface of the injector.
In a preferred embodiment of the injector, the internal chamber 3 and the piston 5 preferably exhibit a cylindrical shape, the piston 5 being axially slidable internally of the internal chamber 3.
The piston 5, at a first end thereof 5a, is provided with an axial protuberance 6 about which a seal 7 is positioned for sealing against the lateral wall of the internal chamber 3. As the seal between the piston 5 and the internal chamber 3 is positioned at the first end 5a of the piston 5, at a second end thereof 5b it advantageously projects externally of the internal chamber 3 such as to be associable to means which are suitable for actuating the sliding action thereof. This characteristic enables an easy activating of the injector, and in particular enables realising the device of the present invention, for depositing a matrix of points of fluid on a surface. The device comprises a head 9 provided with a first body 10 and a second body 11 to which the hollow body 2 and the piston 5 of a plurality of injectors 1 of the present invention are respectively associated. In a preferred embodiment of the device, the first and the second body 10, 11 are flat, and the hollow bodies and the pistons of the injectors 1 are associated thereto in an ordered matrix fashion. The ordered matrix obviously imitates the matrix according to which the points of fluid are to be deposited on a surface. To this end the apices 2a of the hollow bodies 2 are aligned to one another on a same plane.
The first body 10 and the second body 11 are activatable to move with respect to one another such that each piston 5 can assume the three positions thereof with respect to the hollow body 2 thereof. The movement of the first body 10 and the second body 11 can be actuated by means of any actuator which is suitable for the purpose. As illustrated in the figures, the actuator is preferably constituted by a hydraulic cylinder 12.
The device of the invention is further provided with means for moving, not illustrated for the sake of simplicity, which are predisposed to translate the head 9 between at least an aspirating position of the fluid and an injecting position of the fluid.
During functioning of the device, the head 9 performs a main translating movement between the fluid aspiration position and the fluid injection position. In the fluid aspiration position, the head 9 is above a recipient 12 (illustrated only schematically in figures 1 and 2) containing the fluid, in a position in which the injectors 1 are at least partially immersed internally of the fluid, preferably at least at the tapered end portion of the hollow bodies 2. In this position of the head 9, the injectors 1 are in an initial configuration in which the pistons 5 are in the second position thereof. The first and the second body 10, 11 are activated to distance from one another such that the pistons 5 displace towards the first position thereof, causing fluid to be aspirated.
When the pistons 5 reach the first position, aspiration of the fluid is halted and the head 9 is raised and translated into the position of fluid injection. In this position the apices 2a of the hollow bodies 2, which as mentioned lie on a same plane, are positioned in proximity of a surface on which points of fluid are to be deposited. The first and the second body 10, 11 are neared to one another such that the pistons 5 displace from the second position towards the first position. As mentioned herein above, during this displacement of the pistons 5, fluid is injected through the injection hole 4 of the injectors 1. The stage of injecting the fluid is terminated when the pistons 5 have reached the third position thereof, such that complete injection of the previously-aspirated fluid is guaranteed to have occurred.
In a preferred use of the device, the fluid is constituted by a grout for ceramic tiles. As can be seen in figures 3 and 4, the surface on which the points of grout 13 are deposited is a plane defined by the laying surfaces 20a of an ordered matrix of ceramic tesserae 20. Alternatively the points of grout could be deposited on a support surface or tray on which the ceramic tesserae are subsequently deposited such as to marginally superpose on the points of grout.
A further important advantage of the injector and the device of the present invention is well illustrated in the figures and consists in the possibility of depositing the points of grout at the separation spaces (the lines between the tiles), such that the grout is arranged in part on the laying surfaces 20a and in part penetrates between the ceramic tesserae 20, adhering to the lateral surfaces of the tesserae themselves. Once gripping has occurred, each point of grout ensures a solid connection between the ceramic tesserae 20 between which it is interposed. This important advantage is made possible by the action of injection by means of which each injector 1 deposits its point of grout.

Claims

An injector for viscous fluids, characterised in that it comprises: a hollow body (2), provided with an internal chamber (3) for containing a determined quantity of fluid, and an injection hole (4), which places the internal chamber (3) in communication with an outside of the hollow body (2); a piston (5), sealedly mobile in the internal chamber (3), between a first position, in which the internal chamber assumes a first volume, and a second position, in which the internal chamber assumes a second volume, which second volume is smaller than the first volume.
The injector of claim 1, wherein the piston (5) is predisposed to assume a third position in which the internal chamber (3) assumes a smaller volume than the volume thereof assumed at the second position of the piston (5).
The injector of claim 2, wherein the hollow body (2) exhibits a tapered end portion which is provided with an apex (2a) at which the injection hole (4) terminates.
The injector of claim 3, wherein the internal chamber (3) and the piston (5) exhibit a cylindrical shape, the piston (5) being axially slidable in the internal chamber.
The injector of claim 4, wherein the piston (5), at a first end (5a) thereof, is provided with an axial protuberance (6) about which a seal (7) is positioned for sealing against a lateral wall of the internal chamber (3).
The injector of claim 5, wherein the piston (5), at a second end (5b) thereof, projects externally of the internal chamber (3) such as to be associable to means for activating the sliding movement thereof.
A device for depositing a matrix of points of fluid on a surface, comprising: a head (9) provided with a first body (10) and a second body (11) to which the hollow body (2) and the piston (5) of a plurality of injectors (1) of at least one of the preceding claims are respectively associated, the first body (10) and the second body (11) being activatable to move with respect to one another such that each piston (5) can assume the three positions thereof in relation to the respective hollow body (2).
The device of claim 7, wherein the first body (10) and the second body (11) are flat and the hollow bodies and the pistons of the injectors (1) are associated to the first body (10) and the second body (11) according to an ordered matrix.
The device of claim 8, wherein the apices (2a) of the hollow bodies (2) of the injectors (1) are aligned with one another on a same plane.