ADHESIVE-APPLYING APPARATUS AND METHOD OF APPLYING ADHESIVE, AND APPARATUS FOR APPLYING ADHESIVE ONTO A MOVING FIBER WEB

[001] The present invention relates to an apparatus for applying adhesive according to the preamble of patent claim 1, comprising a supporting structure and an application head disposed movably in the supporting structure, a first adhesive container and feeding means for feeding adhesive from the first adhesive container to the application head.

[002] An object of the invention is also an apparatus according to the preamble of patent claims 12 for applying adhesive to a fiber web for attaching a cut web or a web to be cut to a support surface.

[003] It is known from the prior art in the finishing in paper manufacture to produce at the slitter-winder from a wider (machine) roll a number of narrower rolls by unwinding the wide roll and slitting it into several narrower sections and rewinding the narrower sections into separate rolls. As the separate rolls contain a certain amount of paper the rewinding must be done by forming several rolls. During the so-called set change, the surface of the completed roll, i.e. the end of the paper must be bound to the roll to prevent it from unwinding.

[004] US publication 4,601,4412 discloses a solution with stationary adhesive nozzles arranged in row. Binding the end of a cut web to each separate roll requires in this solution a large number of nozzles. As the width of the separate rolls may at the smallest be for example of the order of 100 mm, a 10 m wide web requires even up to 100 separate nozzles. Thus, the maintenance of this kind of an arrangement is naturally time-consuming and elaborate.

[005] US publication 4,103,840 discloses that applying adhesive on tissue can be provided by means of an application head arranged movable in the transverse direction of the web.

[006] Hot-setting adhesive has recently proved to be a reliable way to bind a roll. The temperature of the hot-setting adhesive must be kept relatively high during the treatment and the application, for example at 120 - 200 ⁰ C, which sets certain requirements on the application equipment and the method.

[007] The object of the invention is to provide an adhesive applying apparatus suitable for applying hot-setting adhesive to a surface or surfaces to be pasted. Further, it is an object of the

invention to provide an apparatus for applying adhesive to a moving fiber web in order to attach a cut web or a web to be cut to a support surface.

[008] According to the invention the adhesive applying apparatus comprises a support structure and an application head disposed movably to the support structure, a first adhesive container and adhesive feeding means for supplying adhesive from the first adhesive container to the application head. It is mainly characteristic to the invention that the application head comprises a second adhesive container and that the feeding means comprise connections in the application head and the support structure within the movement range of the application head so that the application head is movable in the support structure to a position where the connections of the application head and the support structure may be coupled for supplying adhesive from the first container to the second container.

[009] The application head comprises a feeding arrangement for allowing supply of adhesive from the application head, the feeding arrangement providing the energy required by the application.

[0010] According to a preferred embodiment the feeding arrangement comprises a gas tank where the energy needed during the application can be stored as pressure. According to another embodiment there is a potential energy store in connection with the adhesive container; the energy preserved in the store may be used in the feeding of the adhesive.

[0011] The first adhesive container preferably comprises heating means for heating the adhesive and keeping it heated. Particularly when so-called hot-setting adhesive is used, this is an indispensable feature.

[0012] The apparatus for applying adhesive according to the inventions is particularly suitable for applying adhesive to a fiber web in order to attach a cut web or a web to be cut to a support surface. According to an embodiment, the object of the invention is an apparatus for applying adhesive to a fiber web in order to attach a cut web or a web to be cut to a support surface, the apparatus comprising a support structure and an adhesive application apparatus essentially in the direction transverse to the direction of the web.

[0013] Adhesive is applied non-simultaneously compared with the feeding of the adhesive from the first adhesive container to the second adhesive container. Thus, continuous transfer of adhesive between the application head and the support structure is not needed.

[0014] According to a preferred embodiment of the invention heat is transferred to the first adhesive container and the adhesive therein is heated and heat is further transferred to the second adhesive container.

[0015] The other characteristic features of the invention are disclosed in the appended patent claims.

[0016] An adhesive means in this context a substance which, due to its properties as such or through a subsequent treatment, or otherwise, is such that it produces a joint between two surfaces.

[0017] The inventions and its operation are described below with reference to the appended schematical drawing figures of which

Fig. 1 illustrates a side view of a two-drum winder for rewinding a web, which applies the apparatus of the invention; Fig. 2 illustrates an embodiment of an apparatus according to the invention for applying adhesive onto a moving fiber web;

Fig. 3 illustrates another embodiment of an apparatus according to the invention for applying adhesive onto a moving fiber web; and

Fig. 4 illustrates an embodiment of an application head according to the invention.

[0018] Figure 1 illustrates a side view of a two-drum winder of a slitter-winder in a highly schematic illustration. The two-drum winder comprises in this case two drums 10, supported by which the adjacent rolls 12 to be wound are formed. The winder comprises two drums 10.

Also a belt arrangement provided around two guide rolls or a so-called set of belt rolls may be used as the latter drum. The invention is also suitable for a so-called center winder-type slitter winder.

[0019] The winder further comprises a press roll 14 or a corresponding means, which also supports the roll in its position. In order to guide the web W it has been disposed to run via rolls 11 before the first drum, which is the one of the drums that guides the incoming web to the

roll being formed. When the rolls have reached the desired size the full rolls are removed and rewinding of new rolls for example onto a core is started. Then the web running onto each full roll must be cut and the end of the web must be bound to the surface of the completed roll so that the roll stays unwound in the further handling. In order to bind the end of the web, adhesive is applied to the surface of the web so that it remains between the end of the web and the previous rewound layer. For this purpose there is an apparatus 20 for applying adhesive in connection with the two-drum winder. In this embodiment it has been disposed in the direction of the web W just before the first drum. The apparatus comprises a support structure 21 essentially in the direction transverse to the direction of the web, in this case disposed under the web, which minimizes the risk of the support structure causing problems to the web. The apparatus further comprises a first adhesive container 22.

[0020] Figure 2 illustrates an embodiment of an apparatus 20 for applying adhesive according the invention. The support structure 21 of the apparatus comprises an elongated bar or a corresponding means which in this embodiment extends under the partial webs W slitted from the paper web. The support structure comprises guides 24, along which the application head 23 is arranged to move in the support structure. In the embodiment illustrated in Figure 2, there is a first adhesive container 22 at the other end of the support structure in the operation range of the application head 23 defined by the guides 24.

[0021] The adhesive applying apparatus according to the invention is designed particularly for applying so-called hot-setting adhesive which in practice means that handling of the adhesive presupposes that its temperature is substantially higher than the surrounding temperature, typically 120 - 200 ⁰ C. In order to heat the adhesive and to keep it heated, there is a heating means 25 in connection with the first adhesive container, which is illustrated here in a highly schematic manner. Heat is transferred by the heating means to the first adhesive container and the adhesive therein is heated. The heating means is preferably operated by electricity. As the temperature of the hot-setting adhesive is fairly high the first adhesive container 22 has been provided with insulation 26 which in essential portions defines the first adhesive container 22. The insulation prevents heat from unnecessarily spreading to the environment and also keeps the energy required for heating the adhesive reasonable.

[0022] In the embodiment of Figure 2 the first adhesive container 22 has been provided with a recess 28 limited by the adhesive container from several directions. The size of the recess is such that the application head 23 has space to go into the recess. In order to move the

application head to the recess, also the guides 24 extend to the recess. This arrangement allows the application head to the brought to the recess and kept there when application of adhesive is not in progress. In this way heat may be transferred at the same time also to the second adhesive container of the application head from the same heating means 25. Also the temperature of the application head is maintained adequately high in view of the usability of the adhesive. This embodiment also minimizes the need to separately heat the application head itself. In some cases, the application head may not need separate heating at all.

[0023] The application head 23 illustrated in Figure 2 comprises a second adhesive container 231 which serves as an intermediate store for the adhesive to be applied from the application head. The arrangement includes means for feeding adhesive from the first adhesive container to the second adhesive container of the application head. The feeding means comprise connections both in the application head 233 and in the support structure 232. The connections have been disposed within the movement range of the application head in the connection position. According to the invention the application head can be moved along the guides to the connection position where the connection 233 of the application head and the connection 232 of the support structure can be coupled with each other so as to create a flow connection. When the connections 232 and 233 have been coupled, adhesive may be fed from the first adhesive container 22 to the second adhesive container 231.

[0024] There is also a feeding arrangement 240 in the application head for allowing the feeding of the adhesive from the application head to the surface to be pasted. The feeding arrangement provides the drive for the feeding. In the embodiment of Figure 2, the feeding arrangement includes a gas container 243 for storing pressurized gas in the application head. The application of adhesive is in this embodiment accomplished by means of the gas pressure. The size of the gas container is sufficient to effect feeding of the adhesive volume in the second adhesive container to the application head.

[0025] For filling the gas container the arrangement comprises gas connections 241, 242 both in the application head and in the support structure. The connections have been provided within the movement range of the application head. Then the application head may be moved to a position in which the connection 241 of the application head and the connection 242 of the support structure may be coupled with each other in order to provide a flow connection for the gas.

[0026] There is a nozzle unit 244 for adhesive in the application head, and a valve unit 245 controlling the adhesive flow. A control unit 246 controlling the valve unit has been provided in the application head. Further, the control unit 246 of the application head may be connected over a data transmission connection to the main control system (not illustrated) via connectors 247, 248. While the connectors 247, 248 are connected, the necessary data may be transmitted to the control unit to control the spraying. This kind of data is for example the start and the end position of each separate partial web W, i.e. the position of their edges. Naturally, no application of adhesive is desired between the partial webs. In this embodiment the data transmission connection exists only when the application head is in the data transmission position.

[0027] The apparatus described above works so that adhesive is applied by means of the application head 23 disposed movably in the body structure while the application head moves along the guides 24, and controlled by the control unit. Prior to the application the adhesive to be applied has been transferred from the first adhesive container to the second adhesive container provided in the application head. Thus, adhesive is not applied at the same time with the feeding of the adhesive to the second adhesive container. This arrangement gives the advantage that there is no need to provide between the movable application head and the body structure a resilient adhesive feed hose allowing the movement of the application head.

[0028] Figure 3 illustrates an adhesive application apparatus otherwise similar to the one illustrated in Figure 2, and also the corresponding reference numbers have been used, but in Figure 3 the control unit 246 of the application head is in continuous data transmission connection with the main control system (not illustrated) over a transmitter-receiver unit 247', 248'. The transmitter unit 248' has been provided in the body structure and the receiver unit 247' in the application head. In this way a continuous data transmission connection can be established between the application head and the main control system. Further, it may be a two- way connection if necessary. In Figure 3, the application of adhesive is going on and spraying of the adhesive onto the second partial web is just beginning. The application head moves along the guides in the direction indicated by the arrow.

[0029] Figure 4 illustrates an embodiment in which the first adhesive container 22 has been disposed separate from the connection station 200 connected to the support structure and from the adhesive feeding connections 232, 233 for feeding adhesive from the first adhesive container to the application head. In other respects its operation, as well as the reference

numbers used, corresponds to that of the apparatus of Figure 2. The first adhesive container 22 is heated with a heater 25 in the corresponding way as in the embodiment of Figure 2. Further, the first adhesive container has been enclosed with insulation 26. Figure 4 further illustrates a source of pressurized gas 254 connected via a duct to the connection 242 of the support structure. The pressurized gas can be for example air.

[0030] In this embodiment, the connection station 200 in the support structure further has a heating unit 251 separate from the first adhesive container and an insulation 252 essentially surrounding it. In this way the first adhesive container can be placed irrespective of the location of the connection station 200. The connection station 200 and the first adhesive container are connected to each other via a heated duct or a hose 253.

[0031] Figure 5 illustrates an embodiment of the application head 23 according to the invention. In this embodiment, there is a potential energy store 235 in connection with the adhesive container 231. It may be considered that the basic idea of the invention is that the application head, when it starts moving from the connection station to perform the task of applying adhesive, contains the adhesive needed during the application task in question and also the energy required by the application of the adhesive. This results in that these need not be supplied in real time to the application head. The potential energy store has in this case been created by disposing a flexible partition wall 236 in the adhesive container so that it divides the volume of the container in two parts, in an adhesive store 238 and a work space 239. There is a flexible element provided in the work space, for example a spring 237. In this embodiment, no separate working medium is needed but the adhesive is supplied to the adhesive store 238 at a pressure which is sufficient also for applying it. The feeding pressure of the adhesive is stored in the potential energy store in this case in a compressed spring. The adhesive store and the work space may also be separate chambers connected for example by a duct. Instead of a spring also other means may be used, such as compressible gas, in order to achieve the same influence. This influence may also be produced by a separate actuator in the application head which sets the spring. The spring may be set also by the movement of the application head. The energy required by the application may also be acquired from the movement of the application apparatus in relation to the support structure for example by means of a gear unit.

[0032] It should be noted that only a few most preferred embodiments of the invention have been described above. For example the connection station may be in another location than at the end of the support structure and the coupling of the connections may take place by means of

the movement of the application head or there may be separate members provided for moving the connections. Thus it is evident that the invention is not limited to the embodiments described above but it may be modified for example by combining features from different embodiments to each other and it may be applied in many ways within the scope of protection defined by the appended claims.