CN101107396A - Base units for paper or board machines - Google Patents

Abstract

The present invention relates to a base arrangement for a paper or board machine or equivalent for supporting components or equipment of the paper or board machine. The base means comprises a frame (15) on which means such as rollers (11) of a component/equipment (10) is supportably connected to the frame. The component/equipment (10) is supported on a building (30). According to the invention, the component/equipment (10) is supported on a solid block base (20). The base (20) is supported on a building base (30) by a movable joint (21).

Description

Base units for paper or board machines

technical field

The invention relates to a substrate arrangement for a paper or board machine or equivalent as described in the preamble of claim 1 .

Background technique

Fibrous web machines, especially paper or board machines, comprise different components and equipment, such as finishing equipment such as calenders, which are used to polish the surface of the paper web and make the paper web The surface is smooth. Depending on the required surface quality of the paper web and the intended use of the paper web, there are various types of components and equipment of a paper or board machine, such as calenders. From the point of view of the performance of a part/equipment of a paper or board machine, e.g. a calender, it is important that it is supported as stably as possible on the building both under dynamic and static conditions, especially if its lower part is supported on the ground . In this regard, dynamic stability means that disturbing dynamic excitations are not conducted through the ground and that the damping properties of the ground are stable; static stability means that the ground maintains its shape when carrying loads applied to it. A big problem in prior art applications is that it is difficult to stabilize the substrate sufficiently due to unfavorable or unknown ground conditions. Unstable supports cause a number of problems, including possible increases in disturbing vibrations during operation and permanent changes in the position of supports.

Another problem with prior art paper or board machines is that vibrations of different components/equipment may cause vibrational interactions when the different components/equipment are supported on the same base, while said The interaction of vibrations may result in periodic or chaotic vibration behavior of the entire machine.

With regard to the state of the art, reference is made to European patent EP0972879, which discloses a calender assembly for paper webs or similar materials, the calender comprising a bottom supported frame, which also includes a At least five rollers thereon with a nip formed therebetween and having axes lying in the same plane extending approximately parallel to the frame, the same plane being at an angle to the horizontal. In addition to the lower support surface, the frame also has an upper support surface, by means of which the frame can be supported on a lower mounting surface attached to a building and on a lower mounting surface attached to a building on the upper mounting surface. However, the above-mentioned problems in calendering due to unfavorable and unknown ground conditions cannot be solved by this prior art device, since the attachments of the calender are fixed under both dynamic and static conditions.

As is known from the state of the art, vibrations occur at the bottom of parts/equipment of paper or board machines, for example at a frequency of 20 Hz, which in tall structures such as multi-roll calenders cause early fatigue of the structure , and worst of all, cause process disturbances and structural breaks. As is known from the state of the art, various attempts have been made to solve this problem, e.g. by installing passive dampers in the upper part of components/equipment with a high structure in paper or board machines, thereby adjusting the above vibration frequency For a given desired frequency, typically 7Hz to 9Hz. By using such devices, various attempts have been made to control the machine direction vertical vibrations of the above frequency in the components/equipment itself of a paper or board machine, but it has not been possible to control the vibrations comprehensively.

Favorable ground or substrate conditions are costly. As machine speeds increase, the requirement for a base further adds to the cost of the building in the conventional manner of attaching the machine to the base.

Contents of the invention

It is an object of the present invention to provide a base arrangement for a fibrous web machine, such as a paper or board machine, by means of which the drawbacks of the arrangements known from the prior art can be eliminated or at least reduced. It is an object of the present invention to provide a substrate arrangement for a paper or board machine or equivalent, in which the problems associated with unfavorable or unknown ground conditions can be eliminated or at least reduced, whereby the dynamic fully and stably supported under static conditions.

An object of the present invention is to provide a base device which can comprehensively consider vibrations.

The object of the present invention is to provide a base arrangement which is able to control the vibrations of the part/device itself in a cost-effective and structurally simple manner.

In order to achieve the above-mentioned objects and the objects to be described hereinafter, a substrate arrangement for a paper or board machine or equivalent according to the invention is mainly characterized by what is stated in the characterizing part of claim 1 .

A substrate arrangement for a paper or board machine or equivalent according to the invention is realized in that the substrate is manufactured on a large solid foundation, such as a concrete slab. The block base is preferably reinforced concrete, which may have a damping material among its constituent materials, and depends on the static load-bearing capacity of the ground, the weight of the block base is, for example, twice the weight of the component or equipment, the component Or the equipment may for example be a calender in a paper or board machine or equivalent. Such a block-like foundation forms a static mass for the base of a component or device of a paper or board machine, which does not contain excitation vibrations within itself. The base is sequentially supported on the base of the building through movable joints. Movable linkages allow horizontal and vertical movement of the base, static alignment can be achieved with controllability in the vertical direction by hydraulic actuators. The movable coupling allows the components/equipment of the paper or board machine to remain in the desired position despite possible variations within the base, such as uneven subsidence. The dynamic damping control used in the present invention is based on the identification of vibrations of a part/equipment of a paper or board machine (eg calender) and on the minimization of such vibrations based on changes in the friction properties with viscous damping. The dynamic characteristics of the spring and damping elements used in the present invention are controlled and controllable so that the vibrations of the calender can be damped.

According to an advantageous application of the invention, for different parts/devices of a fibrous web machine, such as a paper machine or a board machine, the individual or required parts or devices are arranged on their own independent bases according to the invention, thus eliminating Interaction of vibrations of different components/equipment.

In the present invention, an undermounted damper can be advantageously used, which generally includes four (at least three) undermounted shock absorbing cylinders resting on a block base (i.e. base plate) corner. When the mechanical alignment is complete, the base plate is mechanically locked by the lower mounted shock absorber. The lower or top portion of the lower mounted shock absorber has a spring member whose spring constant is adjusted so that the operation in the running state is in the supercritical range. The spring member may be made of metal, or the spring member may be a spring member containing an elastic body and gas so that the spring constant can be changed by gas pressure. Additionally, the lower mounted damping device may comprise a variable viscoelastic, energy dissipative type damper that may be controlled to minimize operating speed and measured dynamic motion.

In the present invention, subsidence can advantageously be corrected by means of hydraulic cylinders, so that a component/equipment of a paper or board machine, such as a calender, can reach its initial installation position. When reaching the initial position, the hydraulic cylinder is locked mechanically. Use traditional level measurements to set the position. The static position can be monitored, for example, by means of a laser sensor.

In the present invention, by providing a semi-active mass damper on the base, the control of overall vibrations, especially vibrations arising from the inherent operation of the machine (calender), is advantageously improved, so that the paper machine Or self-excited horizontal and vertical vibrations of parts/equipment of a board machine can also be controlled and said vibrations can be fully controlled.

In the present invention, a semi-active mass damper with variable stiffness K is provided mounted on the base, the variable stiffness of which mass damper is usually produced by means of a pneumatic spring element. The operation of a mass damper is based on the intrinsically known fact that the mass supported by the spring 51 and damping means vibrates at its resonant frequency which is in phase with the excitation vibration occurring at the same frequency in its base phase is opposite. The resonant frequency of the spring-damper-mass system is simply determined by:

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; res</span>}}<span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; Hz</span>}$

Wherein, K is stiffness (spring constant) (kg/s ² );

m is the vibration mass (kg).

The damping should be suitably small so that the resonant motion of the semi-active damping increases, but large enough so that the damper device does not break. Vibrations against the base are converted to dissipative heat in the damper.

In a horizontal installation, the above equation can be written as:

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; res</span>}}<span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}}\mathrm{<span\; class="notranslate">\; Hz</span>}$

Wherein, g is the gravitational acceleration (m/s ² );

s is the amount of compression (m) caused by mass m in the spring.

In this case, the resonance frequency of the mass damper can be adjusted by adjusting the amount of compression s.

In vertical damping, the first equation is applied and a low-friction suspension that eliminates gravity; it is also possible to install a pre-compressed passive spring parallel to the adjustment spring. The base design according to the invention has many advantages: vibrations can be easily controlled due to the movable coupling of the base, and in addition when problematic soils are encountered, they can be managed with low ground structure costs. Thus, the invention enables a faster and simpler construction of buildings. Furthermore, components/equipment of the paper or board machine can be moved more easily to a new installation location, so that the above-mentioned advantages are still obtained when the floor of the new installation location differs from the floor of the previous location.

The invention will be described in more detail below with reference to the accompanying drawings, but the invention is not limited to the details of the accompanying drawings.

Description of drawings

Figure 1 schematically shows an application of a substrate arrangement according to the invention in a calender system.

Figures 2A-2C schematically illustrate the spring and damper arrangement used in the substrate arrangement according to the invention.

Figure 3 schematically illustrates one application of the undermounted damper used in the present invention.

Figure 4 schematically illustrates one application of the movable linkage used in the present invention.

Fig. 5 schematically shows an application of the control device used in the present invention.

Figure 6 schematically shows the systematic frequency displacement between the ground and the components/equipment of the paper or board machine supported by the base.

Figure 7 schematically shows a control circuit arrangement associated with the dissipation of a sudden ground-induced impact affected by the restraint.

Figures 8A and 8B schematically illustrate one application of the semi-active mass damper used by the present invention for damping horizontal and vertical vibrations.

Detailed ways

As shown in Figure 1, the calender 10 comprises six calender rolls 11 in the illustrated application. The calender nip N is located between the calender rolls 11 . The calender rolls 11 are attached to the frame 15 . The vertical frame beam 16 of the frame 15 of the calender 10 is supported on the base 20 by the inclined beam 12, the base 20 according to the present invention is set as a block base, and its lower part is provided with a movable coupling, so The movable link includes a damping and height adjusting member 21, and the damping and height adjusting member 21 includes a spring member 22 and a damping member 23. The damping and height adjustment elements 21 are in turn fastened to the floor 30 of the building.

2A is a schematic diagram of the main features of the base device according to the present invention. In this base device, a damping and height adjustment member 21 and a spring member 22 are placed under the block base 20. The spring member includes air holes 24. By changing the The pressure of the air hole can change the spring constant.

Figure 2B shows a structure using magnetorheological fluid 25 for damping. Reference numeral 26 denotes a controllable magnet, which produces damping according to the formula Bαγ, ie the magnetic flux density is proportional to the damping.

As shown in Figure 2C, according to the formula Fαγ, the compressive force F in the damping is proportional to the frictional damping.

Figure 3 is a schematic diagram of an undermounted damper application. In the lower installed damper 21, there are generally 4 (at least 3) shock absorbing cylinders 23 placed at the corners of the block base 20 (ie, base plate). When the mechanical alignment is complete, the base plate is mechanically locked by the damper cylinder 23 of the lower mounted damper 21 . The lower or top portion of the damper cylinder 23 of the lower installed damper 21 has a spring member 22 whose spring constant is adjusted so that the operation in the running state is in the supercritical range. The spring member 22 may be made of metal, or the spring member 22 may be a spring member comprising an elastic body and gas so that the spring constant can be changed by gas pressure. Additionally, the lower mounted damping means 21 may include a variable viscoelastic damper 31 which may be controlled to minimize the operating speed and measured dynamic motion. It is also possible to replace the gas with another flowing substance.

As shown in Fig. 4, with the present invention, subsidence can advantageously be corrected by means of the hydraulic cylinder 23, so that a part/equipment of the paper or board machine (such as a calender) can reach its initial installation position. When reaching the initial position, the hydraulic cylinder is locked mechanically using a locking device 33 . Use traditional level measurements to set the position. The position can be monitored eg by laser sensing means to minimize vibrations by changing the frictional properties of the viscous damper.

Fig. 5 schematically shows an application of the control device used in the present invention.

Figure 6 is a schematic graph showing the vibration displacement between the ground and the components/equipment of a paper or board machine, in which the main critical frequency Wcr of the system is adjusted by a spring to Well below the operating frequency W _{the operating range} and little damping is used. If the system reaches the resonant region or below the critical frequency, a larger damping can be used according to the following formula.

As shown in Fig. 7, sudden ground-induced shocks (earthquakes) are dissipated through the damping member 21, ie, the damping Δρ is increased through the control system 41 for proper dissipation to occur. In addition, the spring constant Δk can be controlled by the control system 41, so the main resonance frequency of the system can be transferred to a more controllable region.

In the application of the invention as shown in Figures 8A and 8B, a semi-active mass damper 50 with variable stiffness K is placed on the base, the variable stiffness of which is usually produced by means of a pneumatic spring. The operation of the mass damper 50 is based on the intrinsically known fact that the mass 20 supported by the spring 51 and damping means vibrates at its resonance frequency, which is out of phase with that which occurs at its base 30 at the same frequency The phase of the excitation is opposite. The resonance frequency of the spring 51-damper 52-mass 20 system is simply determined by the following formula:

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; res</span>}}<span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; Hz</span>}$

Wherein, K is stiffness (spring constant) (kg/s ² );

m is the vibration mass (kg).

The damping should be suitably small so that the resonant motion of the semi-active damping increases, but large enough so that the damper device does not break. Vibrations against the base are converted to dissipative heat in the damper.

In a horizontal mounting arrangement, the above equation can be written as:

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; res</span>}}<span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}}\mathrm{<span\; class="notranslate">\; Hz</span>}$

Wherein, g is the gravitational acceleration (m/s ² );

s is the amount of compression (m) caused by mass m in the spring.

In this case, the resonance frequency of the mass damper can be adjusted by adjusting the amount of compression s.

As shown in FIGS. 8A and 8B , in one application of the semi-active damper used in the present invention, the simplest way is that the adjustable spring 50 is formed by an elastic body 51 having a fluid-filled (fluid=flow material) cavity 52. The pressure of the cavity 52 is used to affect the stiffness of the spring unit, and at the same time, the compression of the cavity 52 is also used to affect the desired resonance frequency based on the equations given above. The structure of the spring 50 incorporates dissipative damping; this can be increased by increasing the mass of the fluid, eg mixing water and air. The vibrating mass in the figure, ie the mass base according to the invention, is identified with the reference number 20 and is connected to the floor 30 or to an equivalent building base 30 by means of springs 50 .

As mentioned above, the invention has been described with reference to a preferred simplified embodiment thereof, but the invention is not restricted to the details of the described embodiments.

Claims (11)

1. A base arrangement for a paper or board machine or equivalent for supporting a part or device of said paper or board machine, the part or device comprising a frame (15), the frame (15) Having means, such as rollers (11) of the part/device (11) supported in connection with said frame, the part/device (10) being supported on a building (30), characterized in that the part/device ( 10) Supported on a solid block base (20), and said base (20) is supported on the base (30) of the building by a movable joint (21). 2. The base device according to claim 1, characterized in that the solid base (20) is a concrete slab, or a combination of steel and concrete, and the internal damping of the slab is greater than that of a single piece of steel. 3. Base device as claimed in claim 1 or 2, characterized in that, the movable link forms the damping and height adjustment member (21) of the base (20), and the movable link comprises a spring member ( 22) and damping member (23). 4. The base device according to claim 3, characterized in that, the spring member (22) is connected to the height adjustment member, and the spring member (22) can be adjusted so that the parts/ Operation within the operating range of the equipment is in the supercritical range. 5. The substrate device according to any one of claims 1-3, characterized in that the base (20) is provided with a semi-active mass damper (50) for attenuating horizontal and vertical vibrations . 6. Substrate arrangement according to claim 3 or 5, characterized in that the damping properties of the damping element (21; 50) are adjustable. 7. The substrate device according to any one of claims 1-6, characterized in that, the dynamic characteristics of the spring member (22) and the damper member (23) can be controlled by a control system (41). 8. The substrate arrangement according to claim 7, characterized in that the control system comprises: measurements of vibrations of the part/equipment of the paper or board machine and information related to the vibrations; Controllable dampers and spring elements; and control algorithms to minimize vibrations measured from the calender. 9. The substrate device as claimed in any one of the preceding claims, characterized in that the equipment on which the substrate device is provided is a press, a dryer, a coating plant, a calender, a paper cutter or a reel . 10. Substrate arrangement according to any one of the preceding claims, characterized in that at least one of a plurality of different components/equipment of the paper or board machine or equivalent is supported by a single substrate arrangement. 11. Substrate arrangement according to any one of the preceding claims, characterized in that each of the plurality of different components/equipment of the paper or board machine or equivalent is supported by a separate substrate arrangement.

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