JPH0622708B2 - Atomizing head for atomizing thermoplastic highly polymerized materials - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention is of the type described in the general idea of claim 1 for spraying thermoplastic high polymerisation materials, in particular melt adhesives. Regarding spray head.

(Prior Art) The spray head is, as is clear from West German Patent 3543469,
It has the following: At least one first supply pipe for the material to be heated and thereby flowing, a second supply pipe for the gas stream, a mixing chamber connected to the two supply pipes,
Nozzle mouth of the mixing chamber for the spray material to exit, a third feed pipe for another gas stream, and formed below the spray head, connected to the third feed pipe and exiting An exhaust outlet for gas radiation directed at the material to be atomized.

In that case, the gas emission from the exhaust port, when viewed from above the nozzle port, is parallel to each other and passes through the nozzle port, so that the material that is sprayed out and is easily affected by the gas will be subjected to a certain coating process. It is possible to provide a constant shape and directional component as required. A particularly constant spray pattern, especially an elliptical pattern with a relatively long stretch, is obtained. When such a pattern is created from a plurality of juxtaposed spraying heads, the best surface covering is created because of the partial overlap.

In many applications, the material radiation that emerges from the nozzle mouth and is sometimes still unsprayed is continuously moved to the left or right, parallel to the normal exit direction, for any length. Thus, it is possible to avoid the ON / OFF of the material supply switch, which is often inconvenient in the configuration. If elastic threads or strips have to be joined to the substrate by adhesives, a corresponding problem arises, especially in the production of hygiene products, such as baby diapers. The principle solution to this problem is apparent from US Pat. No. 4,711,683, in which case
In addition to the spray head on the support, two spray heads are arranged, one of which emits continuous air radiation,
On the other hand, it directs intermittent air radiation onto the stream of unsprayed adhesive that exits. Thereby, the adhesive flow is moved laterally with respect to the outgoing direction.

However, a disadvantage of these known spraying heads is the relatively labor-intensive construction with separate, externally attachable accessories and correspondingly labor-intensive control.

OBJECT OF THE INVENTION The problem underlying the present invention is therefore to make a spraying head of the kind already described, which does not present the disadvantages mentioned above.

In particular, a spray head is proposed which has a simple and compact construction and guarantees a completely stable and uniform diversion of the outgoing material flow.

This is achieved according to the invention by the features listed in the characterizing part of claim 1.

Suitable embodiments are defined by the features of the dependent claims.

The advantage obtained by the present invention is based on the fact that the outlet for the gas emission is integrated in the spray head itself, so that no attached parts which can be fixed to the outside of the spray head are required. Therefore, it is easy to handle and has a simple and portable structure.

The gas radiation directed at the material to be sprayed laterally is heated by the spraying head, which leads to a precisely defined temperature, which approximately corresponds to the material temperature, and thus when acted on by external gas radiation, Without additional heating from the outside, there is no unavoidable cooling and undesired effects of material coating.

The outlet for the gas emission is directed obliquely downward, so that on the one hand the injected material and, on the other hand, the gas emission have a common directional component, ie vertically downward. Such a synchronized flow guidance of the control gas radiation results in a very stable turning. In particular, with the spray head according to US Pat. No. 4,711,683, unstable diverting flow vortices, which emerge due to the opposing flow directions of the gas radiation and the material, are avoided.

The spray head according to West German patent 3543469 is not suitable for laterally diverting the sprayed material to the outside.
The reason is that the gas radiation, when viewed from above the nozzle mouth, passes through the nozzle mouth parallel to each other. As a result, only the spray pattern is deformed, and the sprayed material is not moved. Moreover, the action of the two outlets for gas emission essentially compliments each other, so that no spray pattern movement is possible. Finally, it becomes clear that in a spray head with two nodules, one for each outlet for the gas flow, cross-contamination that causes nodules in the nodules occurs,
This too does not allow the desired operation without trouble.

It proves to be appropriate if the outlet for the gas emission extends at an angle of approximately 45 ° to the flat underside of the atomizing head, in which case 15 to
Errors up to 20 ° are possible.

For many applications, two side-by-side outlets for gas emission are sufficient, but according to a preferred embodiment more than one outlet is used. That is, in particular with three or four outlets, which are arranged circumferentially in parallel on one side below the spray head.

It also proves to be suitable if the lower part of the spray head is formed into a removable, substantially bowl-shaped nozzle body, which is screwed to the underside of the spray head. And for different use cases, different nozzle bodies can always be prepared, these nozzle bodies
If necessary, screw on the spray head.

SUMMARY OF THE INVENTION The spray head of the present invention is a spray head for spraying a thermoplastic highly polymerized material, in particular a molten adhesive, and a) at least 1 for heated and thus streamed material.
One first supply pipe, b) a second supply pipe for gas flow, c) a mixing chamber connected to the two supply pipes, d) a nozzle opening of the mixing chamber for the material to be sprayed out, e ) A third feed pipe for another gas stream, and f) an exhaust for gas emission directed to the material to be sprayed which is formed below the atomizing head and is connected to the third feed pipe. G) on one side below the spraying head (18) with a mouth, a projection (84) partially ring-shaped and having an inner surface (88) directed towards the spraying material which goes out; And h) the inner surface (88) is provided with at least an outlet for gas radiation which is directed obliquely below the spray material and which translates this material relative to the original spray trail. It is characterized by having two.

The spray head of the present invention is provided with four exhaust ports.

The spray head of the present invention comprises a nozzle support part of the spray head (18).
Partially ring-shaped protrusion (84) screwed to (42)
It is characterized by a nozzle body (41 ') having.

In the atomizing head of the present invention, the nozzle body (41 ') has, on the upper side, a plurality of conduits (8) connecting the gas flow to the end portion 89 having the exhaust port.
It has a short ring tube (81) for distribution to 2).

The spray head according to the invention has an angle of gas emission on the one hand and of the spray material on the other hand of 30 ° to 70 °, respectively, when viewed in the flow direction.
°, especially between 40 ° and 50 °.

In the spray head of the present invention, the inner surface (88) of the protrusion (84) is cut obliquely.

The atomizing head of the present invention has an inner surface (88) having an outlet for gas emission, which is approximately in the axial direction of the atomizing head (18).
It extends at an angle of 30 ° to 60 °, especially 40 ° to 50 °.

In the atomizing head of the present invention, the third supply pipe (66, 68) is provided with a controllable regulating valve (64) for shutting off the gas supply.

This achieves the above object.

EXAMPLES The present invention will be described in detail below by way of examples with reference to the attached schematic drawings.

FIG. 1 shows a device 10 with a melting device 12 for spraying a thermoplastic high polymer material, in particular a melt adhesive. The melting device 12 can have the configuration known from West German Patent 2836545.

The melting device 12 is provided on the upper side with a pouring lid 14 for the highly polymerized material to be filled later.

Next, other details related to certain highly polymerized materials, or "melt adhesives" are described.

The device 10 has a tube 16 shown in the left portion of FIG. 1 to be larger than the right portion. The tube 16 is joined to the spray head 18. Below the spray head, a strip of material that moves in the direction of the arrow and is coated with a melting adhesive.
20 is equipped with a spray nozzle 19 for spraying the melted adhesive. The sprayed melted adhesive that exits is shown in dashed lines in FIG.

Examples of the band-shaped material 20 include hygiene products, particularly baby diapers, and pad materials used for production. An elastic thread or belt is attached under tension to the spray traces and is associated with the strip material. The strip material is therefore drawn and crimped, as is necessary, for example, to occupy the legs of a baby diaper.

The tube 16 is provided with a connecting sleeve 22 at the inlet end and a connecting sleeve 24 at the outlet (exhaust port) end of the tube, these sleeves being provided by means of corresponding counter-members.
And spray head 18 respectively.

At the inlet end of the tube 16, three conduits are guided out through the outer wall. That is, the compressed air inlet tube 28, which is connected to a blocking member formed as a solenoid valve 30. The blocking member acts by compressed air flowing in the direction of the arrow. And the melting device through the plug
There are two conduits connected to 12, a feed pipe 32 and a control pipe 34, which are connected to the heat belt inside the tube 16.

At the outlet end, an exhaust tube 36 for hot air penetrates the outer wall of the tube 16 and is joined to the lower side of the spray head 18.

The tube 16 has, for example, a configuration known from West German Patent 3416105. That is, the air tube is integrated into the tube 16, so that the supplied compressed air and the heated melting adhesive are kept in the tube 16 at a predetermined temperature.

Alternatively, the tube 16 and the compressed air tube can be made separately.

Within the exhaust tube 36 is an adjustable throttle 40 (FIG. 2) for adjusting the amount of compressed air supplied to the spray head 18.

When viewed from the flow direction of the compressed air, the pressure air pipe is branched in front of the solenoid valve 30. That is, one conduit is connected to the solenoid valve 30. On the other hand, the bypass 38 that goes around the solenoid valve 30 is connected to the compressed air tube 28 again at a position behind the solenoid valve 30 as viewed in the flow direction. A small amount of compressed air flows through this bypass 38 compared to the amount of working air, ie not only during the atomization process but also during interruption of operation.

The spraying device 10 which can be seen from FIG. 1 has the following functions. In the melting device 12, the usually solid or at least highly viscous melting adhesive, which is filled from the lid 14, is heated and thereby liquefied. Since the blocking member for supplying the liquefied melted adhesive is also closed (this blocking member is generally in the melting device 12, not shown in FIG. 1), the spray head 18 Then, the melting adhesive has not come out yet.

However, although a relatively small amount of compressed air flows continuously through the bypass 38, this amount of compressed air is negligible compared to the amount of compressed air required during operation. This amount of compressed air flows through the bypass 36 with the tube 16 and the throttle 40 (FIG. 2) and always leaves the spray nozzle 19 of the spray head 18.

At the beginning of the atomization process, a corresponding switch signal is sent, whereby the valve 30 in the compressed air line 28 and the shut-off member of the dissolver 12 are opened simultaneously. The melted adhesive that has been heated and liquefied is stored in the melting device 12 (not shown).
The tube 16 is connected via the connecting member 22 by the high pressure pump.
Sent to. At the same time, the solenoid valve 30 is opened, so that the entire amount of freely used compressed air flows through the solenoid valve 30 and the air tube 28, through the tube 16 and the air tube 36 and into the spray head 18.

At the exit end, the molten adhesive exits tube 16 via sleeve 24 at about the same temperature as it entered tube 16. Compressed air also exits tube 16 through gas tube member 36 at about the same temperature as the melted adhesive.

The compressed air heated in this way is introduced into the melt adhesive by means of a spray head 18 so that the melt adhesive is sprayed, in which case the temperature-controlled air flow has a temperature of become. That is, on the one hand, so that the applied melt adhesive does not solidify too early, but on the other hand it may overheat when it leaves the spray head 18, thereby impairing the properties of the melt adhesive. It is a temperature that does not exist.

Since a relatively small amount of air always flows from the bypass 38 through the tube 16 to the spray head 18, the opening of the solenoid valve 30 and the blocking member for the melted adhesive can occur simultaneously.

FIG. 2 shows a vertical cross-sectional view of the lower part of the spray head 18 having a nozzle body 41 screwed to the spray nozzle 19 and having a substantially small bowl shape. The melted adhesive flowing in from the connection member 24 for supplying the heated melted adhesive then flows downward through the central supply pipe 40 in the support 42 of the nozzle body 41. The nozzle support 42 is substantially cylindrical and has a pointed movable needle valve 44 in the central supply tube for the heated melt adhesive, which needle valve is connected to the supply tube 40.
Along with it, it extends to the lower end of the nozzle support portion 42. At this lower end, a central feed tube 40, also for the heated melt adhesive, is conical, which results in a valve seat. The valve seat is closed by the tip of the needle valve 44. This interrupts the material supply.

According to the example of FIG. 2, a control valve 60 for compressed air is provided on the left side of the nozzle support. Therefore spray head 18
The amount and / or pressure of compressed air supplied to the is adjusted. The regulating valve 60 is connected to the conduit 36 for compressed air (Fig. 1).

The flow path pipe 46 extends from the regulating valve 60 or the connection hole 43 to the lower side of the nozzle support portion 42 and is connected to the ring pipe 48.
The ring tube 48 is formed between the inside of the stepped tube with the reduced diameter of the nozzle support and the outside of the inner wall of the nozzle body 41. Compressed air from this ring tube 48
It flows through an inwardly downwardly extending tube into a mixing chamber which is bounded at the lower end by the inner wall of the nozzle body 41 on the one hand and the lower conical end of the nozzle support 42 on the other hand. It also extends downward in a conical shape.

In other words, the mixing chamber is supplied with compressed air on the one hand and liquid melt adhesive on the other hand, where they are mixed with one another.

The nozzle body 41 is provided at its lower end with an exhaust port 80 for the melted adhesive to be sprayed. Therefore, the sprayed melt adhesive exits the exhaust port 80 as a "melt adhesive curtain" and is applied as a uniform, thin layer onto the substrate 20.

The nozzle support 42 has a second compressed air connection 62 with a second regulating valve 64, which is cycled,
That is, it can be switched intermittently. The connecting portion 62 is connected to the flow passage pipe 68 of the nozzle body 41 via the flow passage pipe 66 of the nozzle support portion 42. A semi-ring pipe (not shown) at the transition between the nozzle support 42 and the nozzle body 41 connects the two pipes 66, 68 with another flow pipe 70 on the opposite side of the nozzle body 41. ing. That is, the nozzle body
The flow path pipes 68 and 70 in 41 are arranged with respect to the center of the nozzle body 41.
They are arranged symmetrically.

The two flow pipes 68 and 70 of the nozzle body 41 have a hemispherical joint 72.
And ended with 74. These nodes are on the outside below the nozzle body 41 and are provided with exhaust ports 76 and 78. In the longitudinal sectional view according to FIG. 2, it can be seen that the exhaust ports 76 and 78 are directed obliquely below to the sprayed melt adhesive exiting the nozzle body 41 via the exhaust port 80.

The two nodes 72 and 74 of the nozzle body 41 and the exhaust port 80 are aligned. However, the exhaust ports 76 and
78 are arranged parallel to each other, and the air radiation that goes out flows too much through the exhaust port 80. That is, the "melt adhesive curtain" that exits through the exhaust port 80 is
It is affected by the air radiation from 74, thereby obtaining a certain shape. Then again, the particular spray pattern is adjusted.

According to the invention, a nozzle body 41 of a spray head 18 as known from West German patent 3543469 is shown in an embodiment according to FIGS. 3 to 6, which embodiment likewise comprises a nozzle support.
It is screwed to 42.

This nozzle body 41 'is provided with a recess in the upper middle, and this recess forms a mixing chamber with the end member of the nozzle supporting portion 42 facing each other, and in this mixing chamber, the central supply pipe 40
Liquefied adhesive and supply pipe 46 (see Fig. 2)
The compressed air from meets.

At the edge, a nozzle body 41 'directed towards the nozzle support 42
A short ring pipe 81 is formed on the upper side of the pipe, and is connected to the supply pipe 66 (see FIG. 2) on the one hand and the four exhaust holes 82 of the nozzle body 41 'on the other hand. As can be seen in FIG. 5, these holes 82 extend radially obliquely downward from the ring tube to the nozzle body 41 '. The four radii associated with the holes 82 each form an angle of 20 ° with each other, so that the four holes 82 include a central angle of approximately 80 °.

On the underside of the nozzle body 41 'there is an exhaust port 80 for the melted adhesive which is also sprayed in the center.

As can be seen in the sectional views of FIGS. 3 and 4, the nozzle body 41 '
Are asymmetrical, that is, according to FIGS. 3 and 4, on the right side, the nozzle body 41 ′ is provided with a projection 84 on the bottom, which projection is substantially It has the shape of a partial ring and extends at an angle of approximately 90 ° or more (see Fig. 5).

The projecting portion 84 is directed toward the exhaust port 80, and is provided with an obliquely cut surface 88 on the inner side of the partial circle in cross section, which surface is the inner surface of the nozzle body 41 ′ having the exhaust port 80. On the other hand, or at an angle of approximately 45 ° to the flat lower side 86 of the projection 84.

The hole 82 (see FIG. 4) extends axially downward from the ring tube 81 to the upper side of the nozzle body 41 'and then leads to the beveled end portion 89 of the hole 82 with the exhaust port on the bevel 88.

Various exit angles are realized by correspondingly forming the extension of the end portion 89 of the hole with respect to the projection 84 or the bevel 88 connecting the holes 82, 89.

In normal operation, compressed air passes through supply line 46 and liquid melt adhesive passes through supply line 40 to the mixing chamber. There, they are mixed, whereby the liquid melt adhesive is sprayed, and thus the "melt adhesive curtain" is exhausted 80
To go down from.

In this case, the valve 64 is still closed, so the spray head
Due to the relative movement between 18 and the substrate 20, a striped spray pattern is produced on the substrate 20.

When the regulating valve 64 is opened, the compressed air passes through the supply pipe 66, the ring pipe 81 and the holes 82 and 89 in the nozzle body 41 ', and then the hole end portion 8
9 exhausts. These holes are located on a partial circle, ie on a quarter circle, and the exhaust port directs the outgoing air radiation to a cone-shaped melt adhesive curtain, which It's coming out of the mouth.

A total of four gas emissions produced in the embodiment according to FIGS. 3 to 6 completely wraps the exiting melted adhesive curtain from all sides while at the same time covering the curtain (according to the illustration in FIGS. 4 to 3). ) Move to the left, thus creating a new translated spray trail.

This movement is interrupted by a new operation of the regulating valve. That is, at this time, the melted adhesive curtain exits the exhaust port 80 unimpeded and again creates the normal spray pattern.

The air radiation exiting the four holes 82, 89 forms a closed "pressure wall" which completely encloses the "melting adhesive curtain" on one side and therefore is evenly and parallelly transferred. Be done. As a result, movement of the spray trace occurs.

The travel distance is adjusted on the one hand by the spatial arrangement of the outlets of the holes 82, 89, but also on the other hand by the pressure or velocity of the exiting air radiation.

Corresponding adjustments are also made to the numbers and positions, especially by changing the angular position of the holes 82,89. For this reason, a plurality of nozzle bodies 41 ', which can be screwed onto the nozzle support 42, are always provided if necessary adjustments have to be realized.

As can be seen in FIG. 5, the nozzle body 41 'has a vertical edge 90 on the lower side.
Equipped with. This edge corresponds to the normal width of the key and is therefore keyed on this edge 90, whereby the nozzle body 41 '
Can be tightened or unscrewed.

SUMMARY OF THE INVENTION A spraying head for spraying thermoplastic highly polymerized materials, especially melt adhesives, comprises: At least one first supply pipe for the material to be heated and thereby flowing, a second supply pipe for the gas flow, a mixing chamber connected to the two supply pipes, a mixing chamber for discharging the atomized material Nozzle mouth, third feed pipe for another gas stream,
And an outlet for gas emission, which is formed on the underside of the atomizing head, is connected to the supply pipe of FIG. 3 and is directed at the outgoing atomized material. The lower side of the spray head is formed on one side with a partial ring-shaped projection having an inner surface facing the material to be sprayed out. And on this inner surface there are at least two outlets for gas radiation which are directed diagonally below the spray material and translate this material in relation to the original spray trace.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus for spraying a flowable thermoplastic highly polymerized material, in particular a melting adhesive, by means of a fixed spray head, and FIG. 2 is a longitudinal section of an embodiment of the spray head according to West German patent 3643469. Fig. 3 is a vertical sectional view of a small bowl-shaped nozzle body of a spraying head according to the present invention, Fig. 4 is an enlarged vertical sectional view of a small bowl-shaped nozzle body according to Fig. 3, and Fig. 5 is a small bowl-shaped nozzle. A view of the body from below, and Fig. 6 show a view of the small bowl-shaped nozzle body from above. Spray head …… 18, Spray nozzle …… 19, Nozzle support…
42, regulator valve 64, supply pipe 66, 68, ring pipe 8
1, hole …… 82, end of hole …… 89, conduit …… 82, protrusion …… 84.

Claims (8)

[Claims] 1. A spraying head for spraying a thermoplastic high-polymerization material, in particular a melted adhesive, comprising: a) at least one first supply pipe for the material to be heated and thus streamed; b. ) A second feed pipe for the gas flow, c) a mixing chamber connected to the two feed pipes, d) a nozzle port of the mixing chamber for the material to be sprayed out, e) another gas flow Spraying head having a third supply pipe for: and f) an outlet for gas emission formed on the underside of the spraying head, connected to the third supply pipe and directed towards the material to be sprayed out G) on one side below the spray head (18) is formed a projection (84) which is partly ring-shaped and has an inner surface (88) which is directed towards the spraying material which goes out; h) The inner surface (88) is directed toward the spray material diagonally below and also Spray head outlet for the gas radiation which moves parallel to the spray mark, characterized in, that at least two there of. 2. A spraying head according to claim 1, characterized in that it is provided with four exhaust ports. 3. A nozzle body (41 ') having a partially ring-shaped protrusion (84) screwed onto a nozzle support (42) of a spray head (18). A spraying head according to claim 1 or 2. 4. The nozzle body (41 ') is provided on the upper side with a short ring tube (81) for distributing the gas flow into a plurality of conduits (82) leading to an end portion 89 having an outlet. The spray head according to claim 3. 5. The angle of the gas emission on the one hand and of the atomized material on the other hand is 30 ° to 70 °, in particular 40 °, when viewed in the direction of flow, respectively.
Spray head according to one of claims 1 to 4, which lies between -50 °. 6. The spraying head according to claim 1, wherein an inner surface (88) of the protruding portion (84) is cut obliquely. 7. An inner surface (88) having an outlet for gas emission.
Is approximately 30 ° to 60 ° with respect to the axial direction of the spray head (18).
7. The spraying head according to claim 6, wherein the spraying head extends at an angle of 40 ° to 50 °. 8. The third supply pipe (66, 68) is equipped with a controllable regulating valve (64) for shutting off the gas supply. A spraying head according to claim 7.