Method for making the foundation slabs of a paper machine

Abstract: The invention concerns a method for making the foundation slabs of a paper machine. In the method, for concreting of the base beam (10), reinforcement strands (11) are fitted inside a mould (M). Before filling-concreting of the mould (M), the base slab (14) is installed in connection with the reinforcement strands (11) and preferably on support of said strands. In the method, after the slab (14) has been installed as sufficiently plane (± 5 mm) and with its face horizontal, the filling-concreting of the base slab is carried out. Upon drying of the concrete cast, the final tightening of the bolts (13) of the base slab (14) is carried out. The ultimate machining of the base slab is carried out on site in the mill space by passing a machining device (20) on support of guides (21), which have been adjusted to a horizontal level, along the slab (14) faces.

Description: The invention concerns a method for making the foundation slabs of a paper machine before the installation proper of the machine, as specified in the pre-characterizing clause of claim 1. From US-A-2 998 216 there is known a method for making foundation slabs, wherein in the method, for concreting of the base beam, reinforcement strands are fitted inside a mould, and wherein before filling-concreting of the mould, the base slab is installed in connection with the reinforcement strands and (preferably) on support of said strands, and wherein in the method, after the slab has been installed as sufficiently plane and with its face horizontal, the filling-concreting of the base slab is carried out. In a further method for the making of the foundation of a paper machine it is known that, in a first step, a support beam is cast with the reinforcement strands. Into the support beams, hole reservations are made for bolts. The slab is installed while the base bolts hang freely and fit into the reservations. Hereupon the bolts of the foundation slab are fixed by concreting. Below the foundation slab mounted on the reinforcement strands at the top face of the base beam, a so-called filling, i.e. installation pieces, is fitted. After the desired correct plane position of the foundation slab has been achieved in the positioning of the slab, a so-called filling-concreting is carried out between the slab and the base beam. Hereupon the bolts in the slab are tightened. Thus, in both known methods before the filling-concreting, the slab must be positioned very precisely to achieve a plane position. Thus, the working step mentioned above is quite difficult, time-consuming and, therefore, costly. The object of the present invention is to provide an improvement of the above method for installation and manufacture of a base slab of a paper machine. The object underlying the invention is achieved by the steps as defined in the characterizing clause of claim 1. The invention will be described in the following with reference to some preferred embodiments of the invention shown in the figures in the accompanying drawing, the invention being, however, not supposed to be confined to said embodiments alone. Figure 1 is a schematic illustration of a prior-art method for installation of the base slab based on filling. Figure 2 shows the locations of two base slabs in relation to one another. One of the base slabs is supported against the bottom of the paper machine at one side of the paper machine, and the other base slab against the bottom of the paper machine, in the machine direction, at the other side of the paper machine. Figure 3 illustrates the method in accordance with the invention, wherein, before the filling-concreting, the base slab is supported on the mould and installed on the reinforcement strands in a sufficiently accurate plane position. Fig. 4 is a schematic illustration of a so-called on-site machining device, by whose means, on site in the factory space, the base slab is finishing-machined to bring it into a horizontal plane. Fig. 1 illustrates a prior-art method for making of the foundation. When the base beam 10 is being cast, reinforcement strands 11 are fitted at the top face of the beam 10 and, in the same connection, hole reservations 12 are made for the bolts 13. After the casting of the concrete, the base slab 14 of steel with its hanging bolts 13 is placed on support of the reinforcement strands 11. The slab 14 is fitted in an accurate horizontally plane position by means of so-called filling, i.e. fitting pieces 15. After a suitable plane position has been achieved, so-called filling-concreting is carried out between the top face of the beam 10 and the slab 14. In the final step the bolts 13 of the slab are tightened. Fig. 2 is an axonometric view of base slabs 14 installed on base beams 10. In the figure, dimensional quantities are indicated to illustrate the relative positions and the dimensional proportions of the slabs. L₁ represents the distance between the slabs, which is 5...12 m. The width L₂ of each slab is 0.6...0.7 m, and the length L₃ of each line of slabs is 30...80 m, depending on the length of the paper machine. The thickness S of a slab is 60...150 mm. The required accuracy of the plane position is ± 0.25 mm. In the prior-art solutions, the machinings of the slab 14 were carried out in workshops, and the holes in the slabs and the other reservations employed in the fixing of a paper machine were also made separately in workshops. The stage of installation itself required high precision, because the slab was installed in its ultimate position, determined by the requirement of plane position, before the filling-casting. After-machining was not carried out. In the invention, attempts have been made to avoid said difficult working step. In the invention, an entirely novel method of installation and manufacture of base slabs has been provided. As is shown in Fig. 3, the base beam 10, which is placed on the beams P₁,P₂, is made by concreting it in the factory space on site into the mould M. The reinforcement strands 11 are fitted into the mould M, and the base slab 14 with its foundation bolts 13 is fitted, with a requirement of accuracy of ± 5 mm of plane position, onto the reinforcement strands 11. At this stage, the filling-concreting is carried out immediately through the holes 14' in the slab 14. Upon drying of the concrete, the bolts 13 of the slab 14 are tightened. The filling-casting holes 14' are not needed necessarily, because, as a rule, the slab is narrower than the width of the concreting space, so that the filling-casting can be carried out between the slab 14 and the mould M wall. According to the invention, the ultimate machining of the base slab is carried out as an on-site run in the factory hall by bringing an on-site grinding device 20 into connection with the base slabs 14 and by guiding the grinding device 20 on the guide rails 21 along the slab faces. Fig. 4 illustrates the ultimate grinding of a base slab 14 in accordance with the invention. The grinding device 20 is guided on the guide rails 21, and after each cycle of longitudinal feeding the device with its guide rails is displaced on the transverse guide rails 22. The guide rails 21 and 22 are fixed to the concrete base C, so that, by means of the device, sufficient feed forces are achieved in the grinding situation. The guides 21,22 are placed in the horizontal plane before grinding. Hereupon the grinding or milling blade 23 of the device 20 is fed into the slab base to be machined. The invention concerns a method for making the foundation slabs of a paper machine. In the method, for concreting of the base beam (10), reinforcement strands (11) are fitted inside a mould (M). Before filling-concreting of the mould (M), the base slab (14) is installed in connection with the reinforcement strands (11) and preferably on support of said strands. In the method, after the slab (14) has been installed as sufficiently plane (± 5 mm) and with its face horizontal, the filling-concreting of the base slab is carried out. Upon drying of the concrete cast, the final tightening of the bolts (13) of the base slab (14) is carried out. The ultimate machining of the base slab is carried out on site in the mill space by passing a machining device (20) on support of guides (21), which have been adjusted to a horizontal level, along the slab (14) faces.

Claims: Method for making the foundation slabs of a paper machine wherein, for concreting of a base beam (10), reinforcement strands (11) are fitted inside a mould (M), and, before filling-concreting of the mould (M), the base slab (14) is installed in connection with the reinforcement strands (11), preferably on support of said strands, and wherein, after the slab (14) has been installed as sufficiently plane (± 5 mm) and with its face horizontal, the filling-concreting of the base slab is carried out, characterized in that upon drying of the concrete cast, the final tightening of foundation bolts (13) of the base slab (14), having been grouted in by the filling-concreting, is carried out, and that the ultimate machining of the base slab (14) is carried out on site by passing a machining device (20) supported by guides (21), which have been adjusted to a horizontal level, along the slab (14) faces. Method as claimed in claim 1, characterized in that the guides (21, 22) of the grinding device (20) are fixed to concrete constructions (C) of the building for the time of the grinding, and before the grinding the guides (21, 22) are placed in the horizontal level. Method as claimed in any of the preceding claims, characterized in that, before the filling-casting into the mould (M), the slab (14) is installed, with a requirement of accuracy of about ± 5 mm of the plane position, so that its face becomes horizontal, and the ultimate machining is carried out to an accuracy of about ± 0.15 mm of the plane position by means of machining carried out on site by guiding a grinding and/or milling blade 23 on the horizontally installed guides (21, 22) and by, by means of drilling units fitted on a sledge, completing the threaded holes to be made into the slabs.

Inventors: HAKALA JAAKKO, SAVOLAINEN EERO, HAKALA, JAAKKO, SAVOLAINEN, EERO
Applicants: VALMET PAPER MACHINERY INC, VALMET PAPER MACHINERY INC.
Application year: 1991
Main classification: F16M5
IPC codes: F16M5