EP1552060A1

EP1552060A1 - Arrangement and method for feeding treatment agent to a treatment apparatus used for treating a fibre web

Info

Publication number: EP1552060A1
Application number: EP03750770A
Authority: EP
Inventors: John Bergman; Esa Forsten
Original assignee: Metso Paper Oy
Current assignee: Valmet Technologies Oy
Priority date: 2002-10-17
Filing date: 2003-10-16
Publication date: 2005-07-13
Also published as: FI20021859L; AU2003271047A1; WO2004035927A1; CN100585076C; FI114032B; FI20021859A0; CN1705798A

Abstract

The object of the present invention is an arrangement for feeding treatment agent to a treatment apparatus used for treating a fibre web, such as a paper and/or board web, from which apparatus the treatment agent is spread to one or more fibre web surfaces, and which comprises at least one application apparatus fro spreading the treatment agent to the fibre web, and which arrangement comprises means for feeding the treatment agent to the treatment apparatus. The means for feeding the treatment agent to the treatment apparatus are, at least mainly, located between the frame and/or foundation bars of the treatment apparatus on the main line of the treatment apparatus. In addition, the object of the present invention is a method for feeding treatment agent.

Description

Arrangement and method for feeding treatment agent to a treatment apparatus used for treating a fibre web

The object of the present invention is an arrangement and method for feeding treatment agent to a treatment apparatus used for treating a fibre web, such as a paper or board web, from which the treatment agent is spread to one or more fibre web surfaces, presented in the preambles of the independent claims hereafter.

In this context, a fibre web, i.e. a moving web, means a web used during manufacturing or further treatment of a material manufactured of a fibre based material. Fibre based materials include wholly or partly fibre composed materials such as different types of papers, boards, tissues, fibreglasses, MDF-products, mineral and glass wool and different textiles, such as fabrics, non-wovens, wadding. In this context, a fibre means a component whose greatest length is greater than its greatest diameter.

For example, when manufacturing paper, board and tissue it is customary to spread different agents on their surface to improve their characteristics, such as strength and printability. For example, agents most typically used to improve the characteristics of paper and board are different surface sizes and coating compositions.

The agents to be added on the surface of a fibre web, such as paper and board, in order to improve their characteristics, can be spread to the web to be treated in several different ways. Typically, the agents to be added are formed into a treatment agent composition i.e. a paste, which is spread to the web with a treatment apparatus, for example, with a roll coater, such as a film transfer coater, short-dwell time coater or nozzle i.e. jet coater. The treatment apparatus can comprise several application means, for example, application means on both sides of the web. The treatment agent composition is delivered to the coating station with the aid of machine rotation. For example, in European Patent Application EP 0916765 a typical coating station machine rotation is presented, where the produced treatment agent batch is transferred to a machine container located in the basement and from where the treatment agent is sucked through a line to a pump. The pump transfers the treatment agent under pressure to a pressure screen located on the machine level above the basement, after which the screened treatment agent is transferred to the coating station's application apparatus located at the machine level. The surplus treatment agent is collected to the application apparatus pool, from which it is returned to the machine container.

In European Patent Application EP 0960980 a method is presented, where the treatment agent is fed to such treatment agent application apparatuses used in paper or board manufacture where the return flow of treatment agent applied is not used.

The machine rotations in use today typically need a lot of space. Because of the lack of space, different parts of the arrangement are located in different parts of the mill, whereby the arrangements to be installed require delivery-specific planning, due to which the planning and installation costs of the machine rotation are high. In addition, especially when renewing machinery, installing the types of machine rotations currently being used to old mills is extremely cumbersome due to the lack of space.

The present invention realizes that by combining the machine rotation and most preferably also the coating manufacture process as a part of the coating station, it is possible, for example, to substantially decrease the size of the machine rotation containers, whereby the total space needed for the machine rotation is substantially decreased. The object of the arrangement and method of the present invention is to eliminate or at least substantially reduce the problems arising from the aforementioned prior art.

The object of the present invention is also to achieve an arrangement, which is compact in size and structure and can be arranged easily and with minimal changes to be fitted to structurally different treatment apparatuses.

In addition, the object of one embodiment of the present invention is to achieve a method and arrangement, with which treatment agent can be fed in particular to such treatment agent application apparatuses used in paper and board manufacture, where return flow of the applied agent is not used.

In addition, the object of one embodiment of the present invention is to achieve a method and arrangement, where the manufacturing process of the coating is a part of the coating process.

To realize i.a. the aforementioned objects, the arrangement and the method according to the invention are mainly characterized by what is presented in the characterizing parts of the accompanying independent claims.

In a typical arrangement according to the present invention, the means for feeding the treatment agent to the treatment apparatus are, at least mainly, located between the frame and/or foundation bars of the treatment apparatus on the main line of the treatment apparatus. In other words, the means are located near the treatment apparatus, either partly or entirely below, above, in front of or behind it, seen in the machine direction. The location of the means can vary between the embodiments of the invention depending on the structure of the treatment apparatus.

In one preferred arrangement according to the present invention, the means for feeding the treatment agent comprise at least one feeding container and one or more pumps. In addition, the means for feeding the treatment agent preferably comprise one or more screens. In this context, feeding container means a container, which functions as an intermediate storage of the treatment agent between the manufacturing apparatuses and the treatment apparatus. From the treatment agent manufacturing process, the treatment agent is led into the aforementioned feeding container with its own means.

In one preferred treatment apparatus according to the present invention the volume of the feeding container is approximately 0.1-3 m³ and typically approximately 0.2- 1 m³. Compared to known treatment agent storage containers, the small size of the feeding container enables the container to be located in direct vicinity of the treatment apparatus as described above.

In one arrangement according to the present invention the treatment apparatus comprises application devices for coating the fibre web from both sides, and means for feeding the treatment agent comprised by the arrangement comprise separate feeding containers for coating application devices coating the web from different sides. This enables to coat the different sides of the web to be treated with treatment agents having different properties. In this context, application devices mean means, with which the treatment agent is applied to the surface of the web. Such devices are, for example, the aforementioned nozzles and short-dwell time stations.

In one preferred arrangement according to the present invention, the means for feeding the treatment agent to one or more application devices comprise at least one auxiliary pump and/or auxiliary screen. In this case, a malfunction of the pump pumping the treatment agent or of the screen screening it will not stop the feeding of treatment agent to the treatment apparatus and thus the function of the treatment apparatus, because the operations of the failed device can be performed with the auxiliary device. In one preferred arrangement according to the present invention, the feeding container comprises sensor means to measure and/or monitor the surface level of the treatment agent in the feeding container. The sensor means can be measuring sensors measuring the surface level or threshold sensors monitoring the surface level, i.e. sensors which give information on the surface level or about whether the surface level is above or below a certain height. The information given by the sensor means can be used, if required, to control an arrangement according to the present invention, for example, the feed of the treatment agent from the manufacturing process of the treatment agent to the feeding container is controlled on the basis of the information.

In one more preferred arrangement according to the present invention, the arrangement comprises means for mixing the treatment agent components, which means are arranged into two or more in series and/or in parallel arranged mixing zones, of which at least some are pressurised. For feeding of components to the mixing zone, for example pumps, gravitational force, shutter feeders or other suitable devices can be used. In the mixing zones, for example static mixers, mixer pumps, mixer tanks or other suitable process devices can function as mixers. An arrangement as described above enables the treatment agent to be used to be manufactured in conjunction with the coating process, which substantially improves the monitoring and control of the arrangement. In addition, the whole arrangement for treatment agent manufacture and processing is formed into a compact and easily controllable entity, and the properties and quality of the treatment agent formed as end product can be well controlled, because the arrangement is carefully controlled. Thus, with the help of the arrangement according to the present invention the properties of the treatment agent and the coating to be produced can be maintained more stable than before, whereupon the runnability of the coating station improves and interruptions caused by the coating are reduced. In addition, an advantage of treatment agent manufacture based on mixing zones is that the mixing order of the components can be controlled and the intensity of the mixing can be controlled with different types of mixing zones.

In one preferred arrangement according to the present invention, a pressure level is arranged into the mixing zone, which pressure level typically is approximately 1 - 10 bar and preferably approximately 2 - 5 bar. Typically, in different mixing zones, different pressure levels prevail, but they can also be equal. For example, components being mixed in a mixing zone and the flow speed used affect the pressure level being used in the mixing zone. The pressure level can be measured and/or monitored for example with a pressure alarm. The control of the mixing zone can thus be arranged for example in such a way, that a standardised mixing effect is used in a mixing zone and the mixing conditions are changed, for example, by adjusting the flow speed. The arrangement is more preferably also pressurised between the mixing zones, whereby the arrangement is preferably pressurised from the raw material feeding pumps all the way to the feeding container.

In one preferred arrangement according to the present invention, the arrangement comprises means for removing and/or reducing air from one or more components being fed to a mixing zone. Thus the amount of air being transferred to the mixture with the components can be reduced, whereupon also the amount of air in the prepared mixture will be reduced.

A more preferred arrangement according to the present invention comprises means and/or the arrangement is connected to means for measuring the properties of the mixture formed from mixed components. More preferably, the means for measuring the properties of the mixture formed from mixed components comprise at least one or more measuring devices arranged after at least one mixing zone. The measuring enables the measurement and control of the recipe and physical properties of the treatment agent with very little delay. The measuring devices can be arranged to measure also the properties of the treatment agent manufactured in some other way at the mixing zones and transferred to the coating station.

In one more preferred arrangement according to the present invention the means for mixing the treatment agent components and feeding the treatment agent are at least mainly arranged inside a casing structure protecting the means. In this context, the casing structure means a structure, inside which the mentioned means are installed. The casing structure size is typically 4.5 - 7.2 m³, i.e. for example 3 - 6 metre wide, 1 - 4 metre long and 1.5 - 3 metre high. The casing structure protects the said means from the effects of the process conditions around the treatment apparatus. The casing structure may be entirely closed or it can protect the said means only in certain directions. The casing structure may, in addition, have one or more doors, manholes or other equivalent structures, which enable access inside the casing structure, for example for maintenance work.

Due to the casing structure, the arrangement according to the present invention can be carried out as sort of a container, which includes all the devices and parts of the arrangement. Thus the functioning of the arrangement can be tested before the arrangement is installed in contact with the treatment apparatus. The actual installation can be carried out quickly by installing the container, including the arrangement, in contact with the treatment apparatus and connecting to the container the necessary operational commodities and by connecting the arrangement to the treatment apparatus and treatment agent manufacturing process or to the feeds of the treatment agent components.

In a typical method according to the present invention, the manufactured treatment agent is fed to at least one feeding container, which is at least mainly located between the frame and/or foundation bars on the main line of the treatment apparatus, the treatment agent is pumped from the feeding container to the treatment apparatus, and the possible return flow is led back from the treatment apparatus to the said feeding container.

In one preferred method according to the present invention, the treatment agent pumped is screened before its feeding to the treatment apparatus. Because the treatment agent feeding container is located in close proximity to the application chamber, also the screening of the treatment agent occurs just before feeding the treatment agent to the application chamber, and no new impurities affecting the final result of the coating process are formed and transferred to the application chamber.

In one preferred method according to the present invention, the amount of treatment agent in the feeding container is measured with sensor means measuring and/or monitoring the surface level of the treatment agent in the feeding container. The information about the surface level given by the sensor means can be used for example to control the amount of treatment agent in the feeding container.

In one more preferred method according to the present invention, the function of the pump pumping treatment agent from the feeding container to the treatment apparatus can be monitored, and when a malfunction is noticed, the pump is stopped and an auxiliary pump is used for the pumping of the treatment agent. The monitoring can be carried out, for example, simply by comparing the control data and the running data of the pump to each other, and if, according to the control data, the pump should be running but the running data does not confirm this, a restart of the pump can be attempted or an auxiliary pump started. Thus malfunction of the pump does not create a long interruption in the feeding of the treatment agent and therefore in the operation of the treatment apparatus.

According to one more preferred method according to the present invention, the treatment agent is manufactured by mixing two or more components in two or more mixing zones arranged in series and/or in parallel, of which at least some are pressurised. This kind of use of several, more preferably consecutive, mixing zones i.e. cascade process, makes it possible to combine the advantages of batch operation and continuous process. In addition, research results proving that the order of dosing the components affects the properties of the treatment agent can be utilized. In a method according to the present invention, the components can be mixed in pairs or several components at once. In addition, the components can be chosen in such a way, that they do not produce any harmful chemical or physico-chemical reactions with each other.

According to one preferred present method, the properties of the treatment agent and/or the mixture of the mixed components are measured with one or more measuring devices arranged after at least one mixing zone. Thus the measurements can be done from the prepared treatment agent or from a mixture of its components. Based on the measurement made, the ratios and/or amount of components being fed to the treatment agent being manufactured can be controlled in different mixing zones, or control the manufacturing process of treatment agent being transferred to the treatment apparatus.

One of the greatest advantages of the present invention is the effectiveness of its use of space.

In addition, an advantage of the present invention is that the planning, installation and start-up of the treatment apparatus and its machine rotation becomes faster and easier, because the feeding arrangement of the treatment agent forms an easily managed entity.

In addition, a solution according to a very preferable embodiment of the present invention enables the combination of the control operations between the manufacturing and treatment arrangement of the treatment agent and the treatment apparatus.

In the following, the invention is described more in detail with reference to the appended drawing, in which

Figure 1 schematically illustrates a flow chart for making the coating according to the invention, Figure 2 schematically illustrates an arrangement according to the invention seen in the direction of the treatment apparatus main line, and

Figure 3 schematically illustrates an arrangement according to the invention seen from diagonally above in relation to the treatment apparatus main line.

Figure 1 schematically and by way of an example illustrates a process chart for an arrangement according to the present invention installed in contact with the treatment apparatus. In this exemplary embodiment, the treatment apparatus is of a type, which treats a fibre web, such as moving paper or board web, on two sides. The treatment apparatus can be, for example, part of the fibre web manufacturing line, such as part of a paper or board machine. The treatment apparatus can also be arranged to operate as a separate unit, treating the fibre web manufactured by one or more fibre web manufacturing machines.

As the figure illustrates, the manufacturing process comprises a number of mixing zones, where the components to be mixed are fed directly, for example, from storage containers or through a screen.

The first mixing zone contains a static mixer 1, which is under 2-5 bar pressure. To the mixer 1, a first pigment, such as calcium carbonate, is led along a pipeline 3 through a first screen 2. In addition, to the mixer 1, a second pigment, such as calcium carbonate is led through a pipeline 5 through a second screen 4. Furthermore, a binder such as latex, is led along a pipeline 7 through a third screen 6, and a dispersing agent along a pipeline 8 to the mixer. From the first mixing zone, the mixture is led, under pressure, along a pipeline 9 to a second mixing zone, where a third pigment, such as kaolin, is added to the mixture before a mixer 10 along a pipeline 12 through a screen 11, and along a pipeline 14 through a screen 13 a fourth pigment, such as kaolin, is added. Pumps can be used to transfer the mixture between the mixing zones, but it can also be performed without pumps. Also, the second mixer 10 is a static mixer, in which a pressure of approximately 2- 5 bar prevails. A dynamic mixer can be used instead of the static one.

From the second mixing zone, the mixture is led under pressure along a pipeline 15 to a third mixing zone.

In the third mixing zone, before mixer 15, into the mixture CMC (carboxy-methyl cellulose) is added along a pipeline 16, and optical brightening agent along a pipeline 17, which can be used to adjust i.e. the mixture. The third mixer 15 is a static mixer, which is under pressure of approximately 2-5 bar. As a third mixer can, in some applications, also a dynamic mixer be used instead.

From the third mixing zone, the mixture is transferred, under pressure, to a fourth mixing zone, which comprises a fourth static mixer 18, which can also be replaced with a dynamic mixer. In the fourth mixing zone, water can be added to the mixture along a pipeline 19. The fourth mixer is under pressure of approximately 2-5 bar.

The mixture of the fourth mixing zone is led to a continuous mixer/dispergator device 20 (rotor/stator based) and the first actual quality measurement is performed, where one or more of the following properties are measured from the mixture: dry matter content, pH, viscosity, chemical composition, temperature, density and air content. The measurement can be performed, for example, using a method and arrangement as described in the applicant's Finnish patent application FI 20010818 or the method and apparatus described in the applicant's US-patent publication US 6,230,550. In Figure 1, reference number 21 illustrates the arrangement described in US-patent publication US 6,230,550 and its connection to the coating manufacturing process on sample line 21 '.

The results of the quality measurement can be used to control the amount of components fed, their feeding ratios and feeding speed, and for controlling the process conditions of the mixing zones, such as for example the pressure prevailing in the mixing zone. In addition, in the method and arrangement according to the invention, more quality measurements can be used than the measurement illustrated in the figure. The number and location of the quality measurements are defined according to the respective measurement and usage needs. Thus the arrangement can also comprise measurements between different mixing zones. In that case the measurements can be carried out for example in such a way, that the first quality measurement is performed after the second mixing zone, when measured parameters could be, for example, the dry matter content, pH, viscosity, chemical composition, temperature, density and air content of the mixture. Thus, in the third mixing zone for example the dry matter content and viscosity can be adjusted according to the first quality measurement. The second quality measurement could be located after the third mixing zone, when measured parameters could be, for example, the dry matter content, temperature and density of the mixture. The method and arrangement according to the present invention can also be carried out in such a way, that the properties of the prepared treatment agent are measured from a surface of material web coated with treatment agent using, for example, reflection measurement and this result is used alone or together with other measurements to control and/or adjust the manufacturing of the treatment agent to be manufactured.

From the mixer/dispergator device 20 the treatment agent i.e. coating mixture is led through a group of screens 22 to a first feeding container 23 and a second feeding container 24, or to deaeration. If a deaeration means is connected to the arrangement, the coating mixture is transferred to the feeding containers from the deaeration means.

In addition, as mentioned above, compounds which form the mixture and which are mixed to it, i.e. the raw materials of the coating, are led to the screens and/or to the mixture, typically from the storage containers with feeding pumps. The agents to be mixed can also be brought, for example, from silos or factory circulation lines. In addition, deaeration means can be connected to the arrangement for one or more compounds to be mixed, when the air content of the compounds to be mixed can be lowered and therefore decrease the amount of air flowing into the mixture. The deaeration means can then be located, for example, between the screen and the mixing zone or before the screen. If the compound to be mixed does not require to be screened, the deaeration can be arranged to the pipeline, for example, just before the pipeline connects to the mixing zone.

The volume of the feeding containers 23 and 24 is approximately 0.3 m³, but their volume can also be greater or smaller, depending on the type of the treatment apparatus and/or the type of the treatment agent. The arrangement also comprises a first transfer pump 25 and a second transfer pump 26 in contact with to the feeding containers for transferring the treatment agent from the feeding containers along feeding lines 27 and 28 to the treatment apparatus. In addition, pressure screens can be arranged between the feeding containers and the treatment apparatus. The treatment agent returning from the treatment apparatus is led to the arrangement along return lines 29 and 30, which is combined to the inlet line, whereby the treatment agent returning from the treatment apparatus is led back to the feeding container. The amount of the treatment agent returning from the treatment apparatus is in the so called non-return cycle arrangements usually 0-25% of the treatment agent fed to the treatment apparatus, and in the so called return cycle arrangements approximately 70-90% of the treatment agent fed to the treatment apparatus. In the feeding containers, there are surface sensors (not shown in the figure), monitoring the surface level of the treatment agent in the feeding container, the surface information from which is sent to the control unit controlling the operation of the arrangement. The control unit either controls the arrangement manufacturing the treatment agent, or transmits the surface information to the control system controlling the treatment agent manufacture in such a way, that the amount of the treatment agent in the feeding container is kept substantially stable by controlling and adjusting the amount of the treatment agent being pumped to the feeding containers. Thus a circulation line can be arranged to the treatment agent manufacturing arrangement, with which the treatment agent can be returned to the manufact ing process, when the treatment agent cannot be pumped to the feeding container, for example, because of an interruption in the treatment process. In a manufacturing arrangement according to Figure 1, the treatment agent circulation can be carried out, for example, by leading the treatment agent from the screen 22 back to the pipeline 9 before the mixer/dispergator device 20.

The treatment agent can be brought to the arrangement according to the present invention also as a prepared product. Then, if the treatment agent manufacturing process is a batch process, the treatment agent is fed to the feeding containers from one or more intermediate containers, in which the prepared treatment agent batches have been pumped. If the treatment agent manufacturing process is a continuous process, the feeding container surface information acts as one of the control parameters for the treatment agent manufacturing process.

The arrangement can comprise a third transfer pump and a pressure screen, which function as auxiliary devices for the arrangement. Both the first and the second transfer containers are then connected, in addition to the corresponding first and second transfer pumps, to the said auxiliary transfer pump, so that during a malfunction of the first or the second transfer pump, either one can be replaced by the auxiliary transfer pump. Naturally, the arrangement comprises the necessary valves, whose positions can be controlled to thus transfer the treatment agent to be pumped along the transfer lines desired.

To the arrangement according to the present invention, other than the aforementioned quality measurements and measuring devices can also easily be connected to measure the properties of the treatment agent. The measuring devices can be installed, for example, to the treatment agent inlet line, to the feeding container or containers, to the treatment agent feeding line and/or to the treatment agent return line. The measurement information given by the measuring devices can be transmitted, for example, to the treatment agent manufacturing arrangement, where the treatment agent manufacturing process can be controlled using the said information.

An arrangement according to the present invention may comprise also a treatment agent screening arranged to the treatment agent return line. In addition, the arrangement can comprise means for heating or cooling of treatment agent arranged, for example, to the treatment agent return line.

An arrangement according to the present invention can also be carried out using only one feeding container. In this case, the treatment agent is led from the one and the same feeding apparatus to the treatment apparatus. Especially when the treatment apparatus is treating the fibre web solely on one side, it is preferable to carry out the arrangement with only one feeding container. Then the size of the container can be increased as desired, without problems with space. Especially, when installing to treatment apparatuses with a high amount of return flow, it might be preferable to increase the volume of the feeding container.

Figures 2 and 3 schematically and by way of an example illustrate an arrangement according to the present invention installed in contact with a treatment apparatus. Figures 2 and 3 by way of an example illustrate an arrangement according to the present invention arranged in an encased space, which forms a container-like structure 40 to protect, for example, the feeding containers, feeding pumps and pressure screens. There is an access into the casing-like structure 40 through a wall, which can be opened. Around the casing like structure, there is a service level 41, which facilitates, for example, performing service procedures to the arrangement.

The casing-like structure with the service level and thereby also an arrangement according to the invention is connected between the treatment apparatus foundation bars 42 and 43 with bars. The casing-like structure 40 can also be arranged to the treatment apparatus with some other applicable method, such as for example arranging the casing-like structure 40 to be supported by the floor surface of the treatment apparatus machine level or the intermediate level. With reference number 44 is shown how the outlets have been arranged to the end of the casing- like structure for the inlet lines, feeding lines and return lines of the arrangement, but the outlets' location can vary according to the installation location of the arrangement.

The devices of the arrangement according to the present invention can also be arranged in connection with the treatment apparatus without the casing-like structure but the casing-like structure for example protects the devices from the effects of the process conditions around the treatment apparatus.

In addition, the arrangement according to the present invention typically comprises necessary means, such as pipelines, valves and pumps to clean the components of the arrangement. As the said means are known per se to persons skilled in the art, they or their operation are not explained any further in this context.

In the arrangement presented in Figures 1-3 the control and management is carried out by connecting the arrangement as a part of the treatment apparatus control and management system. This means, that the treatment apparatus control system controls the regulating units of the arrangement and receives the status and measurement information from the regulating units and sensors so that it, for example, starts up the pumps of the arrangement and receives feeding container surface information. The control of the feeding arrangement of the treatment agent can also be carried out with a separate control system, for example, with programmable logic, in which case the said separate control system would perform the actions described above. The control of the feeding arrangement of the treatment agent can also be carried out by integrating the control as a part of the treatment agent manufacturing process control system, in which case this arrangement would perform the actions described.

It is not intended to limit the invention to the above exemplary embodiments, but on the contrary, a wide interpretation is preferred within the scope of protection of the claims defined below. Thus, even though in Figure 1 the mixing zones are shown connected in series, the mixing zones can also be arranged in such a way, that some mixing zones are parallel, in which case parallel mixing zones can be used to mix agents, which separate mixtures are later, i.e. in a mixing zone serial to the aforementioned, mixed together. In addition, the arrangement can comprise fewer or more mixing zones than illustrated in Figure 1. Also the agents to be mixed and their order of mixing can vary.

Claims

Claims:

1. An arrangement for feeding treatment agent to a treatment apparatus used for treating a fibre web, such as a paper or board web, from which the treatment agent is spread to one or more fibre web surfaces, and which comprises at least one application apparatus for spreading the treatment agent to the fibre web, and which arrangement comprises means for feeding the treatment agent to the treatment apparatus, characterised in that the means for feeding the treatment agent to the treatment apparatus are, at least mainly, located between the frame and/or foundation bars of the treatment apparatus on the main line of the treatment apparatus.

2. An arrangement according to Claim 1, characterised in that the means for feeding the treatment agent comprise at least one feeding container (23, 24), one or more pumps (25, 26) and one or more screens (22).

3. An arrangement according to Claim 2, characterised in that the volume of the feeding container is approximately 0.1-3 m³ and typically approximately 0.2-1 m³.

4. An arrangement according to any of Claims 1-3, characterised in that the treatment apparatus comprises application devices for coating the fibre web from both sides, and that the means for feeding the treatment agent comprised in the arrangement comprise separate feeding containers (23, 24) for application devices coating the web from different sides.

5. An arrangement according to any of Claims 1-4, characterised in that the means for feeding the treatment agent to one or more application devices comprise at least one auxiliary pump and/or auxiliary screen.

6. An arrangement according to any of Claims 1-5, characterised in that the arrangement comprises means for mixing the treatment agent components, which means are arranged in two or more in series and/or in parallel arranged mixing zones, of which at least some are pressurised.

7. An arrangement according to Claim 6, characterised in that in the mixing zone a pressure level has been arranged, which typically is approximately 1 - 10 bar and preferably approximately 2 - 5 bar.

8. An arrangement according to any of the above mentioned Claims, characterised in that the arrangement comprises means and/or the arrangement is connected to means for measuring the properties of the mixture formed from mixed components.

9. An arrangement according to Claim 8, characterised in that the means for measuring the properties of the mixture formed from mixed components comprise at least one or more measuring devices arranged after at least one mixing zone.

10. An arrangement according to any of Claims 1-9, characterised in that the means for mixing the treatment agent components and/or feeding the treatment agent are at least mainly arranged inside a casing (40) protecting the means.

11. A method for feeding treatment agent to a treatment apparatus used for treating a fibre web, in which method treatment agent is manufactured and fed to a treatment apparatus used for spreading the treatment agent, from which the treatment agent is spread to one or more fibre web surfaces, characterised in that the manufactured treatment agent is fed to at least one feeding container (23, 24), which is at least primarily located between the frame and/or foundation bars on the main line of the treatment apparatus, treatment agent is pumped from the feeding container (23, 24) to the treatment apparatus, and the possible return flow is led back from the treatment apparatus to the said feeding container (23,24).

12. A method according to Claim 11, characterised in that the treatment agent pumped from the feeding container (23, 24) is screened before feeding it to the treatment apparatus.

13. A method according to Claim 11 or 12, characterised in that the amount of the treatment agent in the feeding container (23, 24) is measured with a sensor means, which measures and/or monitors the surface level of the treatment agent in the feeding container (23, 24) .

14. A method according to Claim 13, characterised in that the amount of the treatment agent in the feeding container (23, 24) is controlled based on the surface level information given by the sensor means.

15. A method according to any of Claims 11 - 14, characterised in that the operation of the pump (25, 26) pumping treatment agent from the feeding container to the treatment apparatus is monitored and when a malfunction is observed, the pump is stopped and an auxiliary pump is used for the pumping of the treatment agent.

16. A method according to any of Claims 11 - 15, characterised in that the treatment agent is manufactured by mixing two or more components in two or more mixing zones arranged in series and/or in parallel, of which zones at least some are pressurised.

17. A method according to Claim 16, characterised in that the properties of the treatment agent and/or the mixture of the mixed components are measured with one or more measuring devices arranged after at least one mixing zone.