Flow cup for a paint spray gun

Description

[0001] The invention relates to a gravity-feed cup for a paint spray gun according to the preamble of claim 1.

[0002] Gravity-feed spray cups of this type, known from the prior art, feature a mechanical venting device that allows the cup to be vented during the paint spraying process. Venting the cup is necessary to ensure that the spray medium exiting the cup due to gravity and the negative pressure created at the nozzle assembly can flow freely out of the cup, allowing air to flow in without creating a negative pressure within the cup. For this to occur, the volume of the already sprayed liquid must be replaced by air flowing into the cup via the venting device. It is known to incorporate vent openings into the cup for this purpose, which are preferably closable via a valve.

[0003] Such a gravity-feed cup is known, for example, from WO98 / 32539-A. This gravity-feed cup is intended for single use and comprises a plastic container and a lid that fits onto it for sealing the container. The lid has connectors for attaching and securing the gravity-feed cup to a paint spray gun or an adapter attached to it. The gravity-feed cup is placed "upside down," i.e., with the lid facing downwards, onto the paint spray gun. The liquid in the gravity-feed cup, in particular paint, then flows downwards into the paint inlet channel of the paint spray gun due to negative pressure and gravity. To maintain the flow of liquid into the paint inlet channel, a vent is provided in the bottom of the container, which allows pressure equalization between the inside of the gravity-feed cup and the surrounding environment.The ventilation opening can be closed by means of an adhesive strip or a manually operated valve. WO2019 / 012502A2 also discloses a gravity-feed cup according to the prior art.

[0004] The mechanical ventilation devices known from the prior art have the disadvantage that not only can air flow into the gravity-feed cup through the ventilation opening, but in certain situations during the paint spraying process, for example when painting overhead or during rapid swiveling movements of the paint spray gun, liquid can escape from the ventilation opening. This is unpleasant for the painter and can lead to contamination. If paint unintentionally splashes onto the surface being painted through the ventilation opening, this may necessitate re-treatment of the substrate.

[0005] Based on this, the invention aims to provide a gravity-feed cup for a paint spray gun in which sufficient, e.g. automatic, pressure equalization between the inside of the gravity-feed cup and the environment is ensured, while at the same time preventing the escape of liquid during the paint spraying process and during storage.

[0006] This problem is solved with a gravity-feed cup having the features of claim 1. Preferred embodiments of this gravity-feed cup can be found in the dependent claims.

[0007] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying drawings. The drawings show: Figure 1: Representation of a first embodiment of a gravity-feed cup according to the invention, in a partially elevated side view (top) and a top view (bottom); Figure 2:Representation of a second embodiment of a gravity-feed cup according to the invention in a partially elevated side view (top) and a top view (bottom); Figure 3: Partial illustration of a third embodiment of a ventilation opening with a membrane; Figure 4: the membrane of the in Figure 3 shown embodiment in a top view; figure 5: partial illustration of a fourth embodiment of a ventilation opening with a membrane; figure 6: partial illustration of a fifth embodiment of a ventilation opening with a membrane; figure 7: partial illustration of a sixth embodiment of a ventilation opening with several distributed membranes; figure 8: partial illustration of a seventh embodiment of a ventilation opening with a membrane made up of several segments.

[0008] The one in Figure 1The illustrated first embodiment of a gravity-feed cup according to the invention comprises a cup-shaped container 1 and a lid 2 that can be screwed onto it via a thread. Figure 1 (Above) the gravity-feed cup is shown upside down in the position it is in during the paint spraying process. The lid 2 has on its underside (according to the illustration in Figure 1 (above) an outlet nozzle with an outlet opening. A connecting part 3 is molded onto the outside of the outlet nozzle, which serves to attach and secure the gravity feed cup to a paint spray gun or to an adapter arranged between the paint spray gun and the gravity feed cup. In the case of the Figure 1In the illustrated embodiment, the connecting part 3 comprises a thread and a wedge-shaped groove, which interact with corresponding connecting elements on the paint spray gun or an adapter, namely a corresponding internal thread and a pin for engaging in the groove. Both the container 1 and the lid 2 are expediently manufactured from plastic using injection molding.

[0009] Container 1 has walls, namely a bottom la and a frustoconical side wall lb. On the bottom la is a (in the upper illustration of the Figure 1 ) upwards over the base la projecting and circumferential around the outer circumference of the container 1 formed a rim 1c.

[0010] To fill container 1, first remove the lid 2 and place the container upside down on a surface. Then fill it with a liquid, especially paint. After filling, replace the lid 2. To attach the gravity-feed cup to a paint spray gun, turn the cup upside down and attach the connector 3 to the corresponding connector on the paint spray gun or any adapter attached to it. During spraying, the gravity-feed cup is positioned at the top of the paint spray gun, and the liquid in the container flows into the paint inlet channel of the spray gun due to gravity and the suction effect of the nozzle.

[0011] To enable the pressure equalization between the interior of the gravity-feed cup and the environment, which is necessary for the gravity-driven flow of liquid into the paint inlet channel of the paint spray gun, a ventilation device is provided on the gravity-feed cup. This ventilation device is formed by, for example, a circular ventilation opening 6 in the base 1a, in which an air-permeable and simultaneously liquid-tight membrane 4 is inserted. The membrane 4 thus seals the ventilation opening 6 in a liquid-tight manner, but, due to its air permeability, ensures sufficient ventilation of the gravity-feed cup during the painting process.

[0012] The air-permeable and liquid-tight membrane 4 is a porous membrane. Such porous materials allow gaseous substances, especially air, to pass through the material (e.g., by diffusion and / or through the "normal" flow of a gas through the pores of the membrane), but are simultaneously impermeable to liquids, especially paints. Depending on the material composition and properties, these materials are not wetted even by liquids with very low surface tension and remain "breathable," meaning they still allow air to pass through (e.g., by diffusion or flow) even after coming into contact with liquid.

[0013] At the in Figure 1 In the illustrated embodiment, the membrane 4 is clamped in a support and / or protective structure in the form of a frame 5. As can be seen from the illustration of the Figure 1As shown below, the frame 5 is formed by a circular disk 5a, which is connected to an inner cross 5b arranged centrally to the circular disk. The frame 5 formed by the circular disk 5a and the inner cross 5b serves to clamp the membrane 4. The frame 5 is positively inserted into the ventilation opening 6 in the base 1a. Preferably, the frame 5 is clamped in the ventilation opening by means of a clamping connection. This ensures that the frame 5, which holds the attached membrane 4, is replaceable for changing the membrane 4. A replacement of the membrane 4 may be necessary after prolonged use or if dried paint has clogged the pores of the membrane 4.

[0014] At the in Figure 2The illustrated embodiment of a gravity-feed cup for a paint spray gun consists of a gravity-feed cup with a container 1 and a lid 2 that can be attached to it via a threaded connection, wherein the connecting part 3 for attaching and securing the gravity-feed cup to the paint spray gun is not, as in the one shown in Figure 1 In the illustrated embodiment, the gravity feed cup is located on the lid 2, but here it is located on the underside of the container 1. Figure 2 (above) again shown upside down in the position in which it is arranged during the paint spraying process. In this embodiment, the ventilation opening 6 and the membrane 4, which seals it in an air-permeable and liquid-tight manner, are arranged in the lid 2. The membrane 4 can also be used here as in the embodiment of Figure 1The membrane 4 is clamped in a frame 5 which is positively and, in particular, clamped into the ventilation opening. Alternatively, the membrane 4 can be directly molded into the lid 2 during the manufacturing process using injection molding, such that it covers the ventilation opening 6, as shown in the illustration above. Figure 2 visible in the area shown in the elevation view. For this purpose, the membrane 4 is inserted into the injection mold during the injection molding process and the edge 7 ( Figure 2 (above) is overmolded by the plastic during the injection molding process. The membrane 4 then covers the opening 6 in the lid 2, ensuring that the lid 2 is permeable to air to guarantee the necessary pressure equalization during the application process, but at the same time preventing liquid from splashing out of the gravity feed cup through the vent opening 6.

[0015] In the Figures 3 to 8Further embodiments of a ventilation opening 6 with one or more membranes 4 are shown. Analogous to the first embodiment, the ventilation opening 6 is provided in the base of a gravity-feed cup. Alternatively, the ventilation opening 6 can be provided in the lid of a gravity-feed cup, analogous to the second embodiment. However, the ventilation opening 6 can also be provided at another location or in another component of the gravity-feed cup, as further explained below.

[0016] In the third embodiment according to Figure 3 The membrane 4 is embedded in the surrounding material 1a of the gravity cup. A firm anchoring of the membrane 4 is ensured by the fact that the membrane 4 has a thinner anchoring ring 9 around its outer circumference, which is cast or embedded in the material during the primary forming (e.g., injection molding) of the cup bottom (or cup lid, etc.) or at least the part of the cup bottom surrounding the membrane 4.

[0017] Thanks to the reduced height (layer thickness) of the anchoring ring 9 of the membrane 4 compared to the remaining height of the membrane 4 or the cup base, a flat transition from membrane 4 to the surrounding cup base is achieved. Overall, this results in a flat surface for the ventilation opening 6 and membrane 4. This is advantageous because unevenness in the area of ​​the ventilation opening 6 can hinder the complete and undisturbed mixing of, for example, different paint components in the gravity-feed cup, or potentially increase the risk of damage during mixing, etc.

[0018] In Figure 4 is the membrane 4 of the in Figure 3The illustrated embodiment is shown in a top view. The reduced-height anchoring ring 9 can be formed by pressing, compacting, welding, machining, etc. For example, the membrane 4 can also be manufactured with the thinner anchoring ring 9 already in place. The anchoring ring 9 is preferably made of the same material as the rest of the membrane 4. Alternatively, it can also be made of a different material and connected to the rest of the membrane 4 by a material-fit and / or form-fit connection (bonded, welded, clamped, etc.).

[0019] In the fourth embodiment according to Figure 5This is a ventilation opening 6 that is closed by means of a multilayered membrane 4. For example, the membrane 4 can be composed of several porous (i.e., semipermeable) material layers. In this respect, the membrane 4 is a membrane 4 made of several superimposed semipermeable membranes. However, the membrane 4 can also be composed of one or more porous layers and one or more support and / or protective layers. The various layers can lie loosely on top of each other or be connected to each other (materially and / or form-fittingly).

[0020] In the illustrated embodiment, the multilayer membrane 4 is glued into the ventilation opening by means of an adhesive bond 10. Alternatively, it can also be attached in the manner described above or below.

[0021] In the fifth embodiment according to Figure 6This is a ventilation opening 6, which is also closed by means of a multilayer membrane 4. The membrane 6 consists of two outer (top and bottom) porous layers and a central support layer. It encloses a volume (cushion module) in a cushion-like shape. The layers are connected to each other at the outer edge by means of a circumferential adhesive bond 11. Analogous to the third embodiment, the multilayer membrane 4 is embedded in the material of the cup base (cup lid, etc.).

[0022] In the sixth embodiment according to Figure 7 Several (smaller) ventilation openings 6 are provided distributed across the surface of the cup base (cup lid, etc.), each equipped with a membrane 4. The construction and attachment of the membranes 4 can be carried out analogously to the preceding and following explanations.

[0023] In the seventh embodiment according to Figure 8A ventilation opening 6 is closed by means of a segmented membrane 4. The membrane 4 has several segments connected by intermediate support struts; that is, the membrane 4 is made up of several smaller, separate membranes. The construction and fastening of the individual membrane segments can again be carried out analogously to the preceding and following explanations.

[0024] In the embodiments described here, the gravity-feed cup according to the invention ensures sufficient pressure equalization between the interior of the gravity-feed cup and the environment, since the membrane 4, which closes or covers the ventilation opening 6, is permeable to air. At the same time, the membrane 4 prevents liquid from escaping from the interior of the gravity-feed cup to the outside through the ventilation device formed by the membrane 4, because the material from which the membrane 4 is made is liquid-tight.

[0025] The following are further variations and embodiments of a ventilation device according to the invention, some of which have already been explained with reference to the embodiments shown in the figures, and some of which may be provided alternatively or additionally in the embodiments shown or in further embodiments not shown.

[0026] Preferably, a protective and / or support structure (e.g., a cage structure) is provided for fixing and supporting the membrane. For example, the protective and / or support structure can have linear struts that run parallel or at angles to each other. It can include intersecting and / or circular structures. In this respect, the protective and / or support structure can have straight, curved, or ring-shaped struts. The protective and / or support structure can be fabric-like, grid-like, or net-like. It can be connected to the membrane, at least partially, e.g., glued or welded, or simply lie loosely against the membrane. Analogous to the one described in Figure 8 In the illustrated embodiment, the protective and / or support structure can be integrated into the membrane, so that a segmented membrane is formed.

[0027] The protective and / or support structure can be arranged inside and / or outside and / or around the entire membrane.

[0028] Preferably, the protective and / or support structure is designed in such a way that damage to the membrane by the protective and support structure itself is avoided. For example, it is rounded, edgeless, and / or sufficiently deformable towards the membrane.

[0029] Furthermore, the protective and / or support structure ensures, for example, that the surface of the membrane is protected from damage towards the inside of the cup, i.e., that damage is prevented when stirring material with a stirring rod.

[0030] The membrane, or the ventilation opening sealed by the membrane, can be replaceable, captive, or permanently attached to the gravity feed cup.

[0031] The membrane is composed of several membranes. It is a segmented membrane.

[0032] A membrane with multiple membranes distributed across its surface is provided. The membrane can additionally be composed of several membranes stacked on top of each other.

[0033] For example, the membrane is designed to be flush and / or flat with the surrounding component (base, cover, etc.) on the inside and / or outside.

[0034] The membrane can be bonded, chemically bonded, and / or form-fitted to the surrounding component. Preferably, the membrane is injection-molded into the surrounding component. The membrane can also be connected to the surrounding component via an additional component (e.g., a film-like one).

[0035] For example, the membrane can be made up of sections with different materials; for example, an edge area of ​​the membrane can consist of non-semipermeable material, which is designed for bonding (e.g., embedding in plastic).

[0036] The membrane or the ventilation opening provided with the membrane can be located in the cup base, lid, outlet nozzle or cup wall, a closure element or a component attached (inserted) permanently or removable to the outside or inside, e.g. in the form of a cap.

[0037] Preferably, the membrane has a paint-repellent outer layer, at least towards the interior of the gravity cup.

[0038] In a particularly preferred embodiment, the diaphragm is designed such that it has a response pressure of less than 0.3 bar, better less than 0.2 bar, and even better less than 0.15 bar.

[0039] Preferably, the gravity feed cup, in particular the membrane of the venting device of the gravity feed cup, is designed such that a maximum negative pressure of 0.2 bar results in the gravity feed cup when the material withdrawal rate remains constant at 200 g / min.

[0040] As mentioned previously, it can be advantageous for the membrane to be designed as a multilayer membrane, with the layers having different functions. Furthermore, the layers can preferably be spaced apart by spacers in the form of grid-like spacers. For example, one or both outer membrane layers can be designed to be particularly mechanically stable.

[0041] The membrane is preferably designed with hydrophobic properties and / or as a lipophilic polymer membrane (permeable to gas or air, but not permeable to (certain) liquids).

[0042] Preferably, a ventilation process through the membrane can also take place in an operating state in which the membrane is wetted by paint material.

[0043] Preferably, the membrane is designed to be pressure-resistant and enables sealing against the contained paint materials even under a permanently applied static pressure, whereby the pressure results from gravity as well as from outgassing or temperature influences during storage.

[0044] For example, the membrane is designed in the form of a (round) cushion module, which is preferably integrated into the surrounding component in such a way that the membrane has a conical, planar and / or flat transition to the surrounding material.

[0045] Preferably, the membrane is designed as a thin-film membrane in a suitable polymer material, preferably with one or more functional layers and one or more support layers.

[0046] For example, the membrane can be made from one or more of the following materials: polysulfones, polyethersulfones, cellulose, cellulose esters, cellulose acetate, cellulose nitrate, regenerated cellulose, silicones, polyamides, polyamide imides, polyamide urea, polycarbonates, ceramics, stainless steel, silver, silicon, zeolites, aluminosilicates, polyacrylonitrile, polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl chloride, or polypiperazinamide.

[0047] As an alternative to a polymer membrane, a ceramic membrane can also be used.

[0048] Furthermore, the membrane can be made, for example, from a fine fabric or a porous non-woven fabric, with open or closed pores (or from a tightly woven Teflon® fabric).

[0049] For example, the shape of the ventilation opening can be circular, oval, rectangular, polygonal, etc. Instead of a threaded connection, the lid and container of the gravity-feed cup can be connected using a different connection technique, e.g., a snap-fit ​​and / or locking connection, a quick-release connection similar to a bayonet fitting, etc.

[0050] Where a porous membrane is mentioned in this application, it may, for example, be a micro- and / or nanoporous membrane.

[0051] In a particular embodiment, the gravity-feed cup could have, in addition to the vent opening equipped with a membrane, a further venting device, preferably designed as a valve, i.e., manually openable and closeable. The additional venting device can be arranged separately (possibly even on a different component of the gravity-feed cup). Alternatively, it can be located in or on the edge of the membrane. This solution has the advantage that if paints block the surface of the membrane, for example, during prolonged storage of the filled cup, preventing sufficient airflow, the gravity-feed cup could continue to be used without restrictions by opening the additional venting device.

Claims

1. Gravity feed cup for a paint spray gun, the gravity feed cup comprising a container (1) and a lid (2) that can be placed on said container, as well as a connecting part (3) by means of which the gravity feed cup can be placed on the paint spray gun or an adapter, wherein the gravity feed cup has a ventilation device comprising a ventilation opening (6), wherein an air-permeable yet liquid-tight membrane (4) is arranged in or on the ventilation opening (6), which membrane seals the ventilation opening (6) in a liquid-tight manner, characterized in that the membrane (4) has a plurality of segments connected via support limbs located therebetween, and in that the membrane (4) is made up of a plurality of smaller, separate membranes.

2. Gravity feed cup according to claim 1, characterized in that the ventilation opening (6) and the membrane (4) are arranged in a wall (1a, 1b) of the container (1).

3. Gravity feed cup according to claim 1 or 2, characterized in that the ventilation opening (6) and the membrane (4) are arranged in the bottom (1a) of the container (1).

4. Gravity feed cup according to claim 1, characterized in that the ventilation opening (6) and the membrane (4) are arranged in the lid (2).

5. Gravity feed cup according to any of the preceding claims, characterized in that the membrane (4) is enclosed by a frame (5) which fits in the ventilation opening (6) in a form-fitting or clamping manner.

6. Gravity feed cup according to any of the preceding claims, characterized in that the edge (7) of the membrane (4) is cast into a wall of the container (1) or in the lid (2).

7. Gravity feed cup according to any of the preceding claims, characterized in that the membrane (4) is a porous membrane.

8. Gravity feed cup according to any of the preceding claims, characterized in that the membrane (4) is produced from a woven or nonwoven fabric.

9. Gravity feed cup according to any of the preceding claims, characterized in that the membrane (4) is produced from a Teflon® material.

10. Gravity feed cup according to any of the preceding claims, characterized in that the membrane (4) is produced from a hydrophobic material.

11. Gravity feed cup according to any of the preceding claims, characterized in that the membrane (4) transitions, at least on the side facing the gravity feed cup interior, in a planar or flat manner into the component which surrounds the membrane (4) or into which the membrane (4) is inserted.

12. Gravity feed cup according to any of the preceding claims, characterized in that the membrane (4) is designed in such a way that it has a response pressure of less than 0.3 bar, preferably less than 0.2 bar, and further preferably less than 0.15 bar.

13. Gravity feed cup according to any of the preceding claims, characterized in that the membrane (4) is designed as a polymer membrane.

14. Gravity feed cup according to any of the preceding claims, characterized in that a plurality of ventilation openings (6) are provided, in or on each of which a membrane (4) is arranged.

15. Gravity feed cup according to any of the preceding claims, characterized in that the membrane (4) is designed as a multilayered or multi-ply membrane (4), wherein, for example, at least one layer (ply) is designed as a protective and / or support layer, in particular as a support woven fabric or a support grid.

16. Gravity feed cup according to any of the preceding claims, characterized in that the gravity feed cup has, in addition to the ventilation opening (6) provided with the membrane (4), a further ventilation device which is preferably designed in a valve-like manner, i.e., can be opened and closed manually.