Device and method for spraying multi-component plastic material

Abstract

The invention relates to a device (1) for applying a multi-component plastic to a substrate, comprising a metering valve (10) which can be controlled by compressed air as a pressure medium and which has a first valve inlet (11) for a first component (2), a second valve inlet (12) for a second component (3), and a valve outlet (17), the stationary jet mixer (50) comprises a cylindrical mixer housing (53) extending along a longitudinal axis and having a valve-side end (54) and a distal end (55), a mixing element (57) arranged within the mixer housing (53) for producing a component mixture, and an atomizing sleeve (51), the atomizing sleeve is provided on a distal end (55) of the mixer housing (53) and has an inlet (52) for a pressurized atomizing medium. The mixer housing (53) and the mixing element (57) are made of plastic and the mixing element (57) is a one-piece part inserted into the mixer housing (53). The invention further relates to a method for the device (1).

Description

Technical Field

[0001] The invention relates to a device for spraying a multi-component plastic onto a substrate and a method for using the device. Background Art

[0002] A metering valve is known from patent publication US Pat. No. 5,225,892, which has a first valve inlet for a first component and a second valve inlet for a second component. A valve needle is assigned to each valve inlet, wherein the passage to the valve outlet through the needle valve can be opened or closed. The valve needle is connected to a control piston, which is part of the cylinder unit of the metering valve and can be pressurized with compressed air. The metering valve can also be used to dispense highly viscous plastic components. The metering valve is preferably part of a system with which a multi-component plastic can be sprayed onto a substrate in large quantities over a long period of time.

[0003] The stationary jet mixer can be connected to the valve outlet of the metering valve, and the mixer has a cylindrical mixer housing extending along the longitudinal axis. The mixer housing has a valve side end that can be connected to the valve outlet and a distal end provided with an outlet valve needle. The mixing element is arranged in the mixer housing to mix the first component and the second component of the valve outlet of the metering valve separately as evenly as possible. The two components are thus passed through the mixing element along the longitudinal axis from the valve side end to the distal end, so that a uniform mixture of the first component and the second component is produced in the mixer housing. The atomizing sleeve is arranged on the distal end of the mixer housing. The atomizing sleeve has an inlet for a pressurized atomizing medium. For example, the atomizing medium can be compressed air. Atomization makes it possible to apply the mixture of the two components that appear from the outlet valve needle to the substrate in the form of a jet or spray, thereby realizing the most uniform and continuous application of multi-component plastics.

[0004] The desired goal of uniform application with constant layer thickness depends on various factors. For example, for some components or for viscous mixtures of two components, satisfactory results can only be achieved if at least one of the two components is heated beforehand, but this makes the application of multi-component plastics time-consuming and labor-intensive. Although the pressure of the two components leaving the metering valve and also the pressure of the atomizing medium can be varied within wide ranges, varying the pressure does not necessarily lead to the desired result. Summary of the invention

[0005] The invention is based on the object of providing a device for spraying multi-component plastics, with the aid of which even viscous multi-component plastics can be sprayed easily and uniformly onto a substrate.

[0006] The object addressed by the invention is achieved with the combination of features according to claim 1. Examples of embodiments of the invention can be derived from the dependent claims of claim 1.

[0007] According to the present invention, it is arranged that the mixer housing and the mixing element are made of plastic, and the mixing element is a one-piece element, which is inserted into the mixer housing. The mixing element can be a kind of injection molded component, which, on the one hand, makes high-viscosity substances such as sealants, two-component foams or two-component adhesives well mixed due to an efficient mixing structure, and on the other hand, realizes a compact and material-saving design of a static jet mixer. It has been found that the combination of such jet mixers (usually designed for single use) with a metering valve or a system (suitable for spraying a large amount in a long period of time) leads to good results about the uniformity and layer thickness of the plastic layer. It has also been found that the life of the plastic jet mixer and the plastic mixing element used is good enough. For example, from patent publications EP0749776 and EP0815929, it is known that there is a static mixer with a one-piece mixing element made of plastic.

[0008] In one embodiment, the cross section of the mixer housing perpendicular to the longitudinal axis and the cross section of the mixer element perpendicular to the longitudinal axis are each rectangular, preferably square. The cross section of the mixer housing need not be rectangular or square along the entire length of the mixer housing, but only in the section in which the mixer element is accommodated. For example, the mixer housing can have a rectangular or square cross section in the middle section, while the valve side end and the distal end are approximately rotationally symmetrical. Such jet mixers are sold, for example, by the Sulzer Group.

[0009] In one embodiment, the atomizing sleeve can be assembled to the distal end along the longitudinal axis of the mixer housing. A snap-fit ​​connection can be provided between the atomizing sleeve and the mixer housing. The snap-fit ​​connection ensures that the atomizing sleeve is fixed to the distal end in the axial direction. In addition, the snap-fit ​​connection can also have a sealing effect, so that the compressed air supplied by the inlet of the atomizing sleeve cannot escape accidentally. In addition to the snap-fit ​​connection, a separate seal can also be provided. It should be noted that in principle there are other ways (such as screw connection or bayonet lock) to fasten the atomizing sleeve to the distal end.

[0010] A separate adapter can be provided between the valve outlet and the valve-side end of the jet mixer for detachably attaching the jet mixer to the metering valve. This enables the jet mixer to be replaced, for example, with a new jet mixer. If the atomizing sleeve can also be easily pulled out of the distal end of the mixer housing, this replacement can be achieved in a simple manner.

[0011] The adapter may include an adapter housing, a valve connection device for releasably attaching to the metering valve, and a mixer connection device for releasably attaching the jet mixer to the adapter. Thus, in addition to simply replacing the jet mixer, the adapter may also be disconnected from the metering valve, for example to connect different types of jet mixers to the metering valve. The valve connection device and / or the mixer connection device may be integrally formed with the adapter housing. In one embodiment, the valve connection device and the adapter housing are separate components.

[0012] The adapter housing is preferably made of metal. Preferred materials here are stainless steel (eg 304SS) or aluminum.

[0013] The adapter may have a recess for accommodating a divider of the metering valve. The divider is part of the valve outlet of the metering system and ensures that the components leaving the metering valve first meet in the jet mixer and are mixed again.

[0014] In one embodiment, the adapter housing defines a linear passage for the first component and a linear passage for the second component. Thus, the components can pass through the adapter housing without deflection and associated flow resistance.

[0015] Another object of the present invention, to provide a method for spraying a multi-component plastic onto a substrate, is solved by the combination of features according to claim 10. The multi-component plastic is preferably a polyurea, which can be solvent-free and free of volatile organic compounds (VOC). Such polyureas are commercially available, for example as a two-component adhesive under the trade name LINA 888. With LINA 888 polyurea, it is not necessary to heat one or both components and / or the substrate. The curing of LINA 888 is almost independent of weather conditions and results in a reproducible and reliable bond strength. In one embodiment, the components are mixed together in a ratio of 2:1. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention is explained in more detail with reference to the embodiments shown in the accompanying drawings. It is shown that:

[0017] Figure 1 shows a schematic structure of a device according to the present invention;

[0018] Figure 2 Shows a perspective view of an adapter for a device according to the present invention;

[0019] Figure 3 Shows Figure 3 Different views of the adapter (see Figure 3 A to 3D);

[0020] Figure 4 A metering valve for a device according to the present invention is shown;

[0021] Figure 5 A jet mixer for a device according to the invention is shown. DETAILED DESCRIPTION

[0022] Figure 1 A device for spraying a multi-component plastic is schematically shown, which is designated as a whole by 1. The device 1 comprises a metering valve 10, an adapter 30 and a spray mixer 50, which are shown in an exploded state for reasons of clarity. The device 1 is used to mix a first component 2 and a second component 3 to form a multi-component plastic and to apply it in the form of a jet 4 to a substrate (not shown here). The substrate can be, for example, a flat metal sheet. The multi-component plastic can be, for example, a polyurea adhesive.

[0023] The metering valve 10 has a first valve inlet 11 for the first component 2 and a second valve inlet 12 for the second component 3. Compressed air 5 is used to control the metering valve 10 and is supplied to a cylinder unit 13 of the metering valve 10. The compressed air 5 can be used to control the flow of the first component 2 and the flow of the second component 3 through the metering valve 10. Figure 1 In FIG. 1 , two ports 14 of the cylinder unit 13 are shown as an example for a plurality of ports through which compressed air can enter or leave the cylinder unit.

[0024] Starting from the metering valve 10, the first component 2 and the second component 3 are fed through the adapter 30 to the spray mixer 50. The components 2, 3 are guided in separate paths in the metering valve 10 and in the adapter 30. Only in the spray mixer 50 are the components 2, 3 brought together and mixed intensively there. To produce the spray 4, the mixer 50 has an atomizing sleeve 51 with an inlet 52 for compressed air 5. The supply of compressed air 5 to the atomizing sleeve 51 or the control unit for the compressed air 5 for the metering valve 10 is located in Figure 1 Not further shown.

[0025] Figure 2 and 3 An embodiment of an adapter 30 is shown. Figure 3 A shows a side view of the adapter 30 . Figure 3 D is along Figure 3 Cross-sectional view along line dd of A. Figure 3 B shows the adapter 30 from the front and thus illustrates the side facing the jet mixer 50 . Figure 3 C shows the adapter 30 from the rear.

[0026] The adapter 30 has an adapter housing 31, a valve connection means 32 in the form of a swivel nut 32, and a mixer connection means 34. The adapter 30 can be connected to the metering valve 10 by means of the valve connection means 32. The mixer connection means 34 is used to connect the jet mixer 50 to the adapter 30.

[0027] The adapter 30 has a first adapter inlet 35 for the first component 2 and a second adapter inlet 36 for the second component 3. A groove-shaped deepening 49 is provided between the adapter inlets 36, 37. In the adapter housing 31, a first rectilinear channel extends from the first adapter inlet 35 to the first adapter outlet 37 and a second rectilinear channel extends from the second adapter inlet 36 to the second adapter outlet 38.

[0028] The mixer connection device 34 includes an end plate 39 with an elevated portion 41, in which the adapter outlets 37, 38 are located. The end plate 39 is defined by a rim 40, which has four rim sections 40a, 40b, 40c, and 40d. The rim sections 40a and 40c are parallel to each other and extend in a straight line. A pocket 42 of rectangular cross section is formed in each rim section 40a, 40b. Each pocket section 42 also has a small recess 43, which is at the bottom of the pocket section. The rim sections 40b and 40d embody a segment of a circle, the center of which is located on the central axis of the adapter 30 (the central axis of the adapter 30 also embodies the central axis of the rotating nut 33). The circle segments or circular rim sections 40b, 40d each extend within an angle range of approximately 90°. The linear rim sections 40a, 40c are also considered to be flat parts of the circular cover plate.

[0029] The rounded rim sections 40b, 40d each form a rear or trailing edge 44 which can be engaged at the rear by a rotatable snap-on cover (not shown in the drawings) seated on the jet mixer. The mixer connection device can thus also be referred to as part of a snap-on connection.

[0030] The swivel nut 33 has a conical section 45 and a cylindrical (or barrel) section 46, on the inner side of which an internal thread 47 is provided and on the outer side thereof a gripping rib 48 is provided. The gripping ribs 48, which are parallel to each other, extend in the axial direction and are evenly distributed around the circumference. With the aid of the gripping ribs 48, the swivel nut 33 can be screwed onto the corresponding external thread by hand with sufficient force. Although the adapter housing 31 and the end plate 39 are preferably manufactured in one piece from metal, the swivel nut can be a separate injection-molded component made of plastic.

[0031] Figure 4 An example of a metering valve 10 is shown. Figure 4The cylinder unit 13 has four ports 14 for compressed air, by means of which the metering valve 10 can be controlled. A lubrication nipple 15 is provided between the valve inlet 11, 12 and the cylinder unit 13, by means of which lubrication of a control piston which is displaceably mounted in the housing of the metering valve 10 can be achieved. A funnel-shaped mouthpiece 16 forms a valve outlet 17, which provides an opening 18, 19 for each component 2, 3. A trapezoidal separator 20 is provided between the openings 18, 19. When the adapter 30 is connected, the separator 20 engages in the recess 49. Figure 4 Also shown is an external thread 21 which cooperates with an internal thread of a swivel nut 33 of the adapter 30 .

[0032] Figure 5 An embodiment of a jet mixer 50 is shown. The jet mixer has an elongated, cylindrical mixer housing 53 with a valve-side or adapter-side end 54 and a distal end 55. Between the valve-side end 54 and the distal end 55, the mixer housing 53 has a central housing section 56 for receiving a mixing element 57. The mixing element 57 is preferably a one-piece injection-molded plastic component and can therefore be manufactured at low cost. The mixing element 57 defines a plurality of sequentially connected and interconnected chambers through which the components 2, 3 can flow. The mixing element preferably has a square cross section. Therefore, the central housing section 56 is also provided with a square cross section.

[0033] The components 2, 3 are mixed intensively during the flow of the components through the mixing element 57. On the distal end 55, the atomizing sleeve 51, already mentioned above, with the inlet 52 is arranged. The atomizing sleeve 51 thus frames an outlet nozzle 58, from which the mixture of the first component 2 and the second component 3 emerges. The mixture is atomized by the compressed air 5 of the atomizing sleeve 51, and a jet 4 of the previously mixed multi-component plastic is formed.

[0034] A connection means 59 is provided at the valve-side end 54 to connect the mixer housing 53 to the adapter 30. The connection means 59 comprises two pins 60 which are adapted to engage in the pocket 42 of the adapter 30. Thus, when connected, the jet mixer 50 and the adapter 30 cannot rotate relative to each other. Figure 5 Not shown in the figure is a snap-on cover which sits on the mixer housing 53 and can be pushed onto the valve-side end 54 to connect the jet mixer 50 to the adapter 30. For this purpose, the snap-on cover is provided with an undercut which can engage with the rear edge 44 of the adapter 30 by a 90° rotation.

[0035] Reference numerals list

[0036] 1 Device

[0037] 2. First component

[0038] 3. Second component

[0039] 4 Jets

[0040] 5. Compressed air

[0041] 10 Metering valve

[0042] 11 First valve inlet

[0043] 12 Second valve inlet

[0044] 13 Cylinder unit

[0045] 14 Connection

[0046] 15 Lubricating oil nipple

[0047] 16 Mouthpiece

[0048] 17 Valve outlet

[0049] 18 Opening

[0050] 19 Opening

[0051] 20 Divider

[0052] 21 External thread

[0053] 30 Adapter

[0054] 31 Adapter housing

[0055] 32 Valve Connector

[0056] 33 Rotating nut

[0057] 34 Mixer connector

[0058] 35 First adapter inlet

[0059] 36 Second adapter inlet

[0060] 37 First adapter outlet

[0061] 38 Second adapter outlet

[0062] 39 Cover

[0063] 40 Edge (edge ​​sections 40a, 40b, 40c, 40d)

[0064] 41 Rising

[0065] 42 Bag opening

[0066] 43 recess

[0067] 44 tail edge

[0068] 45 Conical section

[0069] 46 Column segment

[0070] 47 Internal thread

[0071] 48 gripping ribs

[0072] 49 Deepening

[0073] 50 Jet Mixer

[0074] 51 Atomizer sleeve

[0075] 52 Entrance

[0076] 53 Mixer housing

[0077] 54 Valve-side end / Adapter-side end

[0078] 55 Distal end

[0079] 56 Central Section

[0080] 57 Mixing element

[0081] 58 outlet nozzle

Claims

1. A device (1) for applying a multi-component plastic to a substrate, comprising a metering valve (10) which can be controlled by compressed air as a pressure medium and has a first valve inlet (11) for the first component (2), a second valve inlet (12) for the second component (3), and a valve outlet (17), A stationary jet mixer (50) comprising a cylindrical mixer housing (53), a mixing element (57) arranged in the mixer housing (53) for producing a component mixture, and an atomizing sleeve (51), the cylindrical mixer housing extending along a longitudinal axis and having a valve-side end (54) and a distal end (55), the atomizing sleeve being arranged at the distal end (55) of the mixer housing (53) and having an inlet (52) for a pressurized atomizing medium, It is characterized in that The mixer housing (53) and the mixing element (57) are made of plastic and the mixing element (57) is a one-piece component which is inserted into the mixer housing (53).

2. The device (1) according to claim 1, characterized in that The cross section of the mixer housing (53) perpendicular to the longitudinal axis and the cross section of the mixing element (57) perpendicular to the longitudinal axis are each rectangular.

3. The device (1) according to claim 1 or 2, characterized in that The atomizing sleeve (51) is attachable to the distal end of the mixer housing (53) along the longitudinal axis of the mixer housing (53).

4. The device (1) according to any one of claims 1 to 3, characterized in that: A separate adapter (30) is provided between the valve outlet (17) of the metering valve (10) and the valve-side end (54) of the jet mixer (50) in order to detachably attach the jet mixer (50) to the metering valve (10).

5. The device (1) according to claim 4, characterized in that The adapter (30) comprises an adapter housing (31), valve connection means (32) for releasably attaching to a metering valve (10), and mixer connection means (34) for releasably attaching a jet mixer (50) to the adapter (30).

6. The device (1) according to claim 5, characterized in that The valve connection means (32) and / or the mixer connection means (34) are integrally formed on the adapter housing (31).

7. The device (1) according to claim 5 or 6, characterized in that The adapter housing (31) is made of metal.

8. The device (1) according to any one of claims 5 to 7, characterized in that The adapter housing (31) has a recess (49) for receiving the separator (20) of the metering valve (10).

9. The device (1) according to any one of claims 5 to 8, characterized in that The adapter housing (31) defines a linear passage for the first component (2) and a linear passage for the second component (3).

10. A method for spraying a multi-component plastic onto a substrate using the device (1) according to any one of claims 1 to 9.

11. The method according to claim 10, characterized in that The multi-component plastic is a polyurea adhesive which is solvent-free and free of volatile organic compounds.

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