JPH0192494A - Frame structure of press part of papermaking machine - Google Patents

Abstract

PURPOSE: To provide a frame device capable of easily and quickly replacing press rolls and press fabrics by installing an intermediate space of which top end is opened up or openable, and supporting a first center roll with the front frame. CONSTITUTION: This frame device for a compact press section of a paper machine is provided by installing an open space T in upward direction of a front frame 70 and a rear frame 90 not connected together and also of a combination of press rolls, supporting a first center roll 30A permanently on a shaft- supporting body 33 fixed to the front frame 70, and supporting a second center roll B with the front downward part 90A of the rear frame 90.

Description

[Detailed Description of the Invention] It's 1st Duke! The present invention provides that the press section of the paper machine includes a set of compact press rolls, several press nips are formed by these press rolls, and the paper web is passed between these nips without several long open stretches. The press section of a paper machine runs mainly supported by the roll surface, and the dewatering press nip in the press section is substantially formed between two smooth-surface center rolls and a hollow-surface center roll. Regarding frame structure.

Once a paper machine has several presses formed by pairs of rolls, the paper web and the dewatering fabric, for example one or a pair of press felts, run between these nips. A press section is usually used. Regarding press structures according to the prior art, the applicant's Finnish patent applications nos. 781428 and 821
No. 995, US Pat. No. 42,093E11, Canadian Patent No. 1,088,525, and Bellois US Pat. No. 4,075,058.

Applicant's press department "Shimpress IIJ (trade name)
is known from the aforementioned US Pat. No. 4,209,381 and this type of press has become a standard solution among various manufacturers of paper machines. This known press offers several advantages of practical importance. The most significant advantage is that the paper web is first
It passes through the first nip and second nip on the pick-up felt throughout the press section as a closed stretch supported by a solid surface, then passes through the third nip to smooth the center roll of the press section. It is to be supported by a surface.

Finnish Patent Application No. 882358 (filed June 3, 1886) of the applicant shows a substantially closed press section of a paper machine for dewatering a paper web,
The press section has a set of compactly shaped press rolls, associated with these separate rolls a number of press nips are formed, and the paper web is substantially disposed between these press nips. Runs supported by roll surfaces without open stretching. What is new in the Finnish patent application cited above is that a press felt is arranged around the press roll, and the press felt passes through a nip formed by the press felt to receive and absorb moisture.
The paper web is transferred between the nips to the oblique plane for substantially the entire journey from the first nip to the last nip of the press section along a substantially S-shaped path, transferring its moisture out of the nip. By traveling while adhering to the surface of the roll, the web surface to be pressed against the smooth surface of the roll changes while moving from one center roll to the other center roll, and becomes the web surface on the opposite side. and that the diameter of said center roll is substantially larger than the diameter of all or most of said hollow-faced press rolls or equivalent press rolls.

The purpose of the Finnish patent application No. 882356 is to
In particular, various problems that occur in the "shim press ■" type press section can be avoided. The aim was to provide a closed press section especially for paper of thin quality.

OBJECT The object of the present invention is to obtain the above-mentioned Finnish patent application no.
The objective is to improve the press section shown in No. H.

Another object of the invention is to improve the frame structure for the press section according to the said Finnish patent application so that the press rolls and the press fabric can be replaced more easily and quickly, thereby reducing the downtime of the paper machine. The aim is to significantly shorten the process and improve the yield of the paper machine.

In the press section according to the Finnish patent application,
Two large diameter center rolls, for example rock rolls, are used whose weight can be on the order of 70 t each. Replacement of such large, heavy rolls presents problems. Another object of the invention is to provide a solution to these problems.

Recently, rigid plastic fabrics have come to be widely used as press fabrics, but since these plastic fabrics cannot be rolled up in bundles in the transverse direction, problems arise in replacing the fabrics. According to , these problems can also be avoided.

A further problem of the invention is to provide a frame part for a press part that can be configured to have a reduced tendency to vibration.According to an embodiment of the invention, this problem is solved by The solution is to make the frame shorter and more rigid than in the prior art, and to allow its lowest frequency of specific vibrations to be higher than in the prior art.

DISCLOSURE OF THE INVENTION In order to achieve these objects and other objects that will become apparent later, the present invention provides a structure in which a frame structure includes a front frame and a rear frame, and an upper end is open between the front frame and the rear frame. The front frame and the rear frame are not connected to each other, at least permanently, above the press rolls of the set of press rolls, and the first center roll is supported on the front frame. , the second center roll is supported on the rear frame, on another front part of the rear frame, or on another intermediate frame, and an intermediate space open at the top is available for changing the press roll and at least the upper press fabric. It is characterized in that the frame structure, press fabric and press rolls are assembled so that it can be made.

Reference will now be made in detail to the accompanying drawings, in which preferred embodiments of the invention are illustrated.

First, the general structure of the press section or press part shown in FIG. 1 will be explained.

The paper web W reaches the press by means of a wire 10 at the front of the paper machine. The paper web W is separated from the wire 10 at the pick-up point P on a downwardly sloping track between the rolls 11.12, transfers to the pick-up felt press fabric 20, and passes to the pick-up roll 2
1 to the press fabric 20 under the action of negative pressure in the suction zone 21a. The paper web W is transferred directly onto the press fabric 20 to the first dewatering nip N1.

The press part consists of two large diameter center rolls 3 with smooth surfaces.
Equipped with 0A and 30B. All press nips that substantially dewater the paper web W in the press section are formed in relation to the center rolls 30A, 30B. The center rolls 30A, 30B may be rock rolls or rolls with a synthetic material surface exhibiting reasonable paper web transport properties, such as a roll with a "Microlock" trade name.

The diameters of rolls 30A and 30B are OA and DB, respectively.
It is expressed as

The first dewatering nip of the press section is formed between the press roll 25 having the hollow surface 2B and the upper first center roll 30A. In the first nip M1, the press fabric 20 is used not only as a press fabric but also as a member for transferring water from the paper web W to the outside. The guide rolls and tension rolls of the press 20 are designated by the reference numeral 22, and the readjustment device by the reference numeral 23.

After the first nip N1, the paper web W is supported and strongly adhered to the smooth surface of the first center roll 30A, and then passes through the second nip N2 (the press roll 45 having the hollow surface 46 and the first center roll 30A). (formed during). The press fabric 40, which has received moisture, is passed through a second nip N2, with guide rolls and stretching rolls 42.
42a, 42b, readjustment device 43
readjusted by. Smooth surface 3 of center roll 30A
1 adheres more strongly to the paper web W than to the press fabric 40, so after the second nip N2, the paper web W moves along the center roll 30A in the same way as after the first nip N1, and its smooth surface 31 and is strongly pressurized so as to come into contact with it.

The paper web W is then transferred onto a second, lower, larger diameter center roll 30B (substantially identical to the first center roll 30A) after as short an open stretching WO as possible or after a corresponding nip. .

Associated with the second center roll 30B is a third nip N3, which is formed between the press roll 55 having a hollow surface 56 and the second center roll 30B. Press fabric 50 is passed through the third nip and guided by guide and stretch rolls 52. 3rd nip N3 and (if any) 4th nip N4
After that, the web W is connected to the dryer wire 60 of the dryer section.
, with a very short open stretch. The dryer wire 80 is guided by a guide roll 61 and placed as close as possible to the transfer roll 62.
The paper web W then passes, adhering to the surface of the dryer wire 80, to the retraction cylinder 83 of the dryer section or to the corresponding first dryer cylinder and then to the first dryer device (formed by the dryer cylinder 64). (preferably single wire stretching is applied)
to move to.

The first nip Nl is disposed on the upper part of the circumference of the first center roll 30A, and the second nip N2 is disposed at an inner arc distance of approximately BO'' to 120'' from the first nip N1.
The paper web W then moves along with the first center roll 30A over the next arc of about 60° to 120°, so that the arc of the paper web W in contact with the first center roll 30A is about 180". becomes.Center roll 3
A cleaning doctor 32 for keeping the smooth surfaces 31 of the center rolls 30A and 30B clean is arranged on the free arc of the center rolls 30A and 30B.

A third nip N3 is formed in relation to the second center roll 30B, and if possible a fourth nip is formed in the zero paper web W within an arc of about 120° to 270 are in contact.

In the press section shown in FIG. 1, the paper web W is transported along a substantially S-shaped path or its mirror image, or is supported on the smooth surfaces of center rolls 30A, 30B, so that The surface of the web W placed on the center roll 30A for the press fabric 20.40, which is rougher than the surface 31 of the center roll 30A, is exchanged on the center roll 30B and pressed against the smooth surface 31 of this roll. Therefore, both sides of the paper web W are treated symmetrically, and the texture of the paper web W with the distribution of fillers and microstructures becomes substantially symmetrical when the dewatering direction is also taken into account.

In principle, the diameter of the center rolls 30A and 30B is as follows:
1400-2000mm, preferably 1500-175
0 mm (7) range, for example about 1600 mm. Center roll 30A.

The diameter of press roll 30B is the same as that of press roll 25.4 which forms nips N1-N3 in association with center rolls 30A, 30B.
5.55 in diameter.

Center rolls 30A, 30B are placed as close as possible to each other keeping in mind the construction and operational aspects of the paper machine. Surface 3 of center rolls 30A and 30B
1 is in the range from 20 to 80 mm, preferably from 40 to 50 mm. center roll 30
The horizontal distance glIE between the vertical center lines of A and 30B is Dν
This distance glE, which is greater than 2, is the center roll 30B
It is important to pay attention to the replacement (removal) of the

The frame portion of the press section shown in FIGS. 1, 2 and 3 includes a front frame To, an intermediate frame 80 and a rear frame 90, which are placed on the foundation 100 of the paper machine room. It has a similar structure. The intermediate frame 80 is disposed below the compact press roll set.The frame portion according to the present invention is characterized in that the front frame 70 and the rear frame 90 are not connected to each other;
Above that, that is, above the set of press rolls, there is a free open space T, by which the second
As will become clear in connection with the figures and the description of FIG. 3, changing of press rolls and press fabrics is substantially easier and faster.

This means that the front frame 70 and the rear frame 90 are not connected to each other, at least permanently, by a rigid frame beam body.

The front frame 70 includes single-sided cross beams 72 and frame side portions fixed to these cross beams. At the top of the front frame 70 there is a tensioning device 71 for the upper guide roll 22a of the press fabric 20. Front frame 70 on the service side of the paper machine
There are openable intermediate pieces 76 through which the first press fabric 20 is exchanged. The first center roll 30A is permanently supported on a bearing support 33 fixed to the front frame 70. The bearing support 33 is attached to the oblique front surface 79 of the front frame 70.
is fixed to. Since the press roll 25 of the first unit N1 is also arranged in relation to the front frame 70, the bearing support of the press roll 25
It is fixed to 3. The intermediate portion 73 is provided with a moving crab knit 7 for the purpose of applying (loading) a load to the nip Nl.
5 is connected to the front portion of the front frame 70 by a horizontal articulation joint 74. - The intermediate frame 80 includes a single-sided cross beam 82 and side frames, of which on the service side of the paper machine there is an openable intermediate section 8B. The guide roll 52 of the lower fabric 50 is connected to the intermediate frame 80
and is supported on the intermediate portion 83. 3rd nip N
The press roll 55 of No. 3 is also supported on the intermediate frame 80, and the bearing support of the press roll 55 is mounted on the intermediate portion 83.
is fixed to. The middle part 83 is a dynamic crab knit 85
horizontal articulation joint 8 so as to be loaded and rotated by
4 to the intermediate frame 80. Furthermore,
Associated with the intermediate frame 80 may be a cross beam 81.

In conjunction with this cross beam, means for extracting the press rolls 55, for example a roller conveyor line, may be arranged.

The second center roll 30B is supported by a lower front portion 90A of the rear frame 90, and the lower front portion is fixed to the rear frame body by an intermediate portion 90B.

In FIG. 4, the press section includes a fourth nip N4 formed by rolls 30B and 59, and the rear frame 90 has a center roll 30B disposed below. It consists of one part so that it is fixed to the. Bearing supports (not shown) of the press roll 58 of the fourth nip N4 can be fixed to the intermediate parts, and these intermediate parts are connected to the front part of the rear frame 80 so as to be loaded and rotated by the moving crab knit. has been done.

When using the rear frame 90 consisting of two frame parts 90A and 90B, the middle part 90B may be omitted. Alternatively, in FIG. 4, the bearing support 34G of the second center roll 30B can be
G, and is rotatably coupled to the front surface of the rear frame 90 by a horizontal connecting joint 35G and by a movable crab knit 36C. Horizontal articulation joint 35C preferably connects roll 5
5. Place it on a straight line drawn almost through the center point of 30B.

The bearing support of the press roll 45 forming the second nip N2 is fastened to an intermediate part 93 which, by means of a horizontal articulation joint 94, loads the front side of the rear frame 90 or its projecting part 97 into the nip N2. It is fixed so as to be rotatable by a movable crab knit 95 in order to provide the following. Adjacent guide rolls 22b, 42b of the first press fabric 20 and the second press fabric 40, which are arranged close to each other in the free space T between the front frame 70 and the rear frame 80, are attached to the intermediate part 38. Yes, the middle part 38 is the first center roll 30
It is fixed to the upper part of the bearing support 33 of A.

The middle portion 73 of the press roll 25 of the first knob N1 is
It can be fixed to the bearing support 33 of the center roll 30A or its protruding part by means of a releasable intermediate part or a joint. Similarly, the intermediate portion 93 of the press roll 45 in the second nip N2 is also
3 or a protruding portion thereof. Here, different loads are coupled to the intermediate portions 73, 93, and the bearing supports of the rolls 25.45 are connected to these different loads.

The replacement of each press fabric associated with a press frame according to the invention will now be described with reference to FIG.

When replacing the press fabric 20, the pick-up point P is opened by removing the old fabric and moving the pick-up roll 21 to position 21A. By rotating the press roll 25 toward the front frame 70 by the movable crab knit 75, the nip N1 is opened. Open the intermediate piece 76 to create an intermediate space? 8
Release A. Upper guide roll 22a is moved from its tensioning device 71 along path A to an inward retention point relative to the upper part of front frame 70 to position 22A.

Similarly, the guide roll 2 arranged on the center roll 30A
2b is position 2 located in relation to the front frame 70;
It is moved along the route to the holding location 2B.

It was open to fabric loop 2OA. Fabric roll 20 supported on exchange pole 205
0 is brought to the service side of the paper machine on lift wire 210, and fabric loop 2OA is brought to the service side of the paper machine on lift wire 210.
Intermediate space 7 [(A) in the position shown in the figure is transferred to a position inside the front frame 70.

Fabric loop 20A is then unfolded and intermediate piece 7
6 and move the rollers 22a, 22b along paths A, D to their normal positions while opening the fabric loop 20A.

To replace the lower fabric 50, the nip N3 is opened by opening the intermediate piece 86 in the frame and rotating the intermediate portion 83, the press roll 55, and the guide roll 52a fixed thereto to the lower position by the movable crab knit 85. It is opened and the guide roll, if located in the lower space, is moved up into the interior of the intermediate frame 80 to the upper position 52c.

Thereafter, the fabric roll 500 supported on the exchange ball 505, which has been opened to form a fabric loop 50A, is transferred into the intermediate frame 80 through the intermediate space 8eA and spread into the bottom space. This closes the intermediate piece 86. Tension lower fabric 50 to close nip N3.

By opening the second upper fabric 40, removing the old fabric, and moving the roll 45 by the moving crab knit 95, the nip N2 is opened, and the upper guide roll 42a placed on the tension device 91 is moved to the rear frame 90. The vehicle moves along route B to a holding location 42A, which is a position 42A above. Similarly, centalonil 30A
The guide roll 42b arranged above the rear frame 90
The user moves along the route C to the reservation location, which is the upper position 342B. The intermediate piece 96 was opened and the lift wire 41 was opened to form the fabric loop 40A.
Place the new fabric on the roll 400 placed on the replacement ball 405 supported by the intermediate space 9
[Rolls 42A, 42A, 42A, 42A, 42A, 42B, 45 and along paths B, C to open positions 42B, 42B, 42A, 42A, 42A, 42A, 42A, 42A, 42A, 42A, 42A, 42A, 42A, 42A, 42A, 42B, 45, and along the cross beam 92, along paths B, C to open positions 42A, 42B;
By moving 42B, fabric loop 4OA is released from its dual roll 400 to its full length.

Closing Nip N2 and Intermediate Piece 86 and Tensioning Fabric 40 As seen from the above description and FIG. It can be used efficiently when exchanging items.

The exchange of each roll using the frame structure of the present invention will be described below with reference to FIG. By suspending the lift loop 211 of the lift wire 210 by the shaft bearing, the suction roll 2! while in position 21A.

Compact roll set rolls 30A, 30B, 2
5°45, 55.59 are exchanged by an open space T in the middle. Alternatively, the lowest press roll 5
5 can be changed by means of a roller conveyor arranged in relation to the beam 81 by pulling out the roll 55 in its longitudinal direction to the service side while one end of the roll 55 is supported by a wire 551.

In connection with the exchange of press rolls, press fabric 2
0.40 adjacent guide rolls 22b, 42b are routed as previously described and along C to the inner position 22B.

42B through space T to the holding position.

Nip M1. Release N2 and replace press roll 25.45 if necessary. In Fig. 3, press roll 4
5 is replaced by hanging from the shaft support on the loop 451 of the lift wire 450.

If one or both of the rolls 25.45 do not need to be replaced, the dimensions of the frame section will be
．． 45 is moved by the moving crab knit 75.85 at its inner position (in FIG.
, 95A) so that the space between rolls 25.45 is open to the henchman so that rolls 3OA, 30B have enough space to pass between rolls 25.45. determined. In FIG. 3, the lift loops 310 of the lift wires 300 are fixed to the shaft bearings of the center roll 30A, and the center roll 30A is moved upward by these wires through the space T and, if necessary, on the paper machine. It can be rotated in the direction above the press section. The removal of the roll 30B is performed using the lift wire 305 (the lift loop 315 is connected to the roll 30B).
This can be done after the removal of the roll 30A. Roll 30B can also be withdrawn longitudinally from the paper machine when roll A is in a position where the distance between rolls 30A, 30B is equal to distance E.

The press roll 55 can be removed after removal of the rolls 30A, 30B via the space T or by longitudinally pulling it out without removing the rolls 30A, 30B, as described above.

The new roll is placed in its working position by the reverse order of operations as described above.

Move the roll up and replace the ball 205.405.505
One or more conventional traverse cranes operating in the ceiling of the paper machine room may be used to support the paper machine room.

Press rolls, especially large and heavy center rolls 30A,
30B can be replaced by so-called middle lifting (a method in which the roll to be replaced is supported at its center of gravity by one lift wire). Here, the lift wire is fixed to two V-shaped lift loops that are open downward.

Middle lifting is the preferred exchange mode because it most safely rotates each roll above the press, towards the paper machine, and facilitates transport of the rolls.

The length L of the open space T in the direction of the paper machine shown in Figure 1
In addition to replacing the press fabric and press rolls, it is necessary to determine this with sufficient consideration, taking into consideration the minimum size of the frame portion of the press section and the geometric shape of the press section. be done. center roll 30
In relation to the diameters of A and 30B, it can be seen that L=kxD, where k is between 1.5 and 3, preferably about 2.

In addition to making it easier and faster to change the press rolls and press fabrics, the frame section according to the invention improves operational safety and saves space, especially on the service side of the paper machine. It becomes less. This is because there is no need to move the press roll longitudinally to the service side. Another advantage is that the construction is simplified by eliminating the need for conveyor means necessary for longitudinal transport, for example roller conveyors. In the past, these devices have been used in conjunction with small press roll sets, which has been problematic. Furthermore, as described above, the structure of the press section is made more compact, so the space is reduced and equipment costs are also reduced.

The present invention also applies to the case where the center rolls 30A and 30B are arranged at substantially the same height.

According to the present invention, a frame structure of a press section of a paper machine is disclosed, which press section includes a set of compact press rolls, by which several press nips are formed, and the paper web is passed through these compact press rolls. Between the nips, it runs mainly supported by the roll surface, without some long open stretches. All the dewatering press nips N1, N2, N3 in the press section consist of two smooth-sided center rolls 30A, 30B and a hollow-sided press roll 25.4.
5.55. The frame structure has a front frame 70 and a rear frame 80, between which there is an open or openable intermediate space T, the frame 70.90 is located above the press rolls of the set of press rolls. , the first center roll 30A, which is not coupled to each other, at least permanently, is supported on the front frame 70, and the second center roll 3QB,
Rear frame 90. It is supported by another front portion 90A of the rear frame 90 or another intermediate frame. These frame structures, press fabrics and press rolls are assembled in such a way that an intermediate space T open at the top is available for the exchange of the press rolls and at least the upper press fabric 20.40.

Since the present invention can be implemented with various modifications other than those described above, the specific configurations described above are merely illustrative.
This is not intended to limit the invention.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view showing the press section according to the present invention together with its frame structure, Fig. 2 is an explanatory diagram showing a state in which the press fabric is replaced in the press section shown in 1IN, and Fig. 3 is fJJ1 diagram. FIG. 4 is an explanatory diagram showing a state in which the press rolls are replaced in a manner corresponding to FIG. 2 in the press section shown in FIG. FIG. 6 is a schematic side view showing a supported variant of the present invention. Part of the thunder 20.40. , , , press fabric 30.3
OA, 30B, press roll 25.45, 55. ,
Press roll 70...Front frame 90...Rear frame 80A0110. Frame part (front part) N1-N3
．． ,,Nip (dehydration press nip) T...Intermediate space W, Web Patent applicant Valmet Paper Machinery Incorporated Agent Number Takao Maruyama

Claims (1)

[Claims] 1. The press section of the paper machine includes a compact set of press rolls, which form several press nips, and the paper web is transported between these nips in a number of press rolls. A paper machine running without long open stretching, supported mainly by the roll faces, in which a dewatering press nip in the press section is formed essentially between two smooth-faced center rolls and a hollow-faced center roll. In the frame structure of the press section, the frame structure includes a front frame and a rear frame, and between the front frame and the rear frame, there is an intermediate space whose upper end is open or can be opened, and the front frame and a rear frame is supported above the press rolls of the set of press rolls, at least permanently in communication with each other, a first center roll is supported on the front frame, and a second center roll is supported on the front frame, The frame structure, the press, is supported on another front part of the rear frame or on another intermediate frame, such that the intermediate space open at the top is available for the exchange of the press rolls and at least the upper press fabric. A frame structure of a press section of a paper machine, characterized in that fabric and press rolls are assembled. 2. A frame structure as claimed in claim 1, in which between the nips of the press section, the paper web follows a substantially S-shaped path along the entire length from the first nip to the last nip of the press section. By running while adhering to the surface of the smooth center roll, the surface of the paper web to be pressed against the smooth surface of the roll is changed while moving from one center roll to the other, and web surfaces, the diameter of said center rolls being substantially greater than the diameter of all or most of said hollow surfaces or similar press rolls, said center rolls being substantially one above the other in a horizontal distance; disposed at a distance as short as possible from each other, the upper center roll being supported in relation to the front face of the front frame, and the lower center roll being supported in relation to the rear frame, preferably at the front face of the rear frame. A frame structure characterized in that it is supported in relation to its parts. 3. The frame structure according to claim 2, wherein the rear frame includes a rear frame portion having a height equal to the overall height of the paper machine, and a front portion of the rear frame fixed to a lower part of the rear frame by an intermediate portion. A frame structure comprising: a lower center roll supported above the front portion. 4. A press unit according to any one of claims 1 to 3, comprising: a first fabric, preferably also a pick-pup fabric, passed through a first nip of the press unit; The rearmost guide roll of the second upper fabric passed through the second nip is supported directly or via an intermediate portion on the bearing support of the first center roll, these guide rolls being juxtaposed. , separable and movable in connection with the change of fabric and roll, said guide roll of the first fabric being movable into an inward position in relation to the front frame in its retention position. , wherein the second fabric guide roll is movable to an inward position in relation to the upper part of the rear frame to its retention location. 5. In the frame structure according to any one of claims 1 to 4, the upper press roll of the first nip formed between the first upper center roll and the hollow-faced press roll is fixed to the intermediate portion. and the intermediate portion is connected in relation to the forward portion of the forward frame by a horizontal articulation joint, the intermediate portion being adapted to load and open the first nip. A frame structure characterized in that it can be loaded and rotated by an effect unit. 6. The frame structure according to any one of claims 1 to 5, wherein the press roll of the second nip formed between the first center roll and the hollow-faced press roll is coupled to the intermediate portion. A frame structure, characterized in that the intermediate portion is rotatable by a power unit to open and load the second nip by means of a horizontal articulation joint on the front portion or protruding portion of the rear frame. 7. Frame structure according to any one of claims 1 to 6, characterized in that the lower center roll is fixed in relation to the rear frame by an intermediate part fixed to the rear frame, preferably by a horizontal articulation joint. A frame structure characterized in that the intermediate portion is rotatable by a power unit. 8. The frame structure according to any one of claims 1 to 6, wherein the frame structure is arranged between a front frame and a rear frame, preferably between a front lower part of the front frame and a rear frame. the intermediate frame is disposed below the center roll; a press roll forming a third press nip together with the second center roll is supported on the intermediate frame; and the hollow surface Press rolls and guide rolls with
supported on said intermediate frame by an intermediate portion so as to be pivotable by a power unit about a horizontal articulation joint to open and load the third nip, the roll or guide roll of press fabric being arranged in at least the third nip; A frame structure, characterized in that it is threaded through and supported on the intermediate frame. 9. 9. A press unit according to any one of claims 1 to 8, wherein the upper guide roll of the first fabric rests on a tensioning device and is connected to the upper part of the front frame to facilitate replacement of the first fabric. A press part characterized in that it is separable and movable to its holding position inwardly in relation to the above. 10. Frame structure according to any one of claims 1 to 9, wherein the upper guide roll of the second upper fabric passed through the second nip is fixed in relation to the tensioning means, and the exchange of the second upper fabric A frame structure characterized in that it is movable from its normal operating position to an inward position to facilitate. 11. The frame structure according to any one of claims 1 to 10, wherein the first nip and the second nip of the press section include a first nip and a second nip on both sides of a vertical plane disposed through the central axis of the first center roll. The hollow-sided press rolls of the nip are formed in relation to the upper half of the upper center roll, and the press rolls are spaced apart from each other such that the center roll can be exchanged using said free space via the space between them. The frame structure is characterized in that the frame structure is movable away from each other. 12. Frame structure according to any one of claims 1 to 11, wherein the intermediate portions of the press rolls of the first and/or second nip are fixed by an articulating joint and further comprising a separable joint and/or a separable joint. A frame structure characterized in that the intermediate portion is fixed to the support box of the upper center roll, the first press roll is fixed to the front frame, and the second press roll is fixed to the rear frame.