PRESS SECTION IN A PAPER MACHINE

Abstract: The invention relates to the press section in a paper machine. It comprises a roll combination (1-5), the rolls of which form one or a plurality of nips (N1, N2, N3). In addition, the press section comprises members for guiding the paper web through the press section and members for guiding one or a plurality of felts (6, 7) or the equivalent through the press section. The frame construction connected to the press section comprises a front frame (8), a rear frame (9) and an intermediate frame (10) con­ necting these two from above the press section. At least one roll of the roll combination (3, 5) provided in the press section is fixed to the auxiliary frame (13, 14), which is disposed to be rotatable about a shaft (19, 20). The auxiliary frame additional­ ly comprises members (15, 16), by means of which the auxiliary frame (13, 14) can be detachably locked to the intermediate frame (10).

Description: The invention relates to a press section in a paper machine, comprising a roll combination of at least two rolls which form at least one press nip, for guiding the paper web through the press section and members for guiding at least one felt into contact with the press section, a frame construction including a front frame positioned before said roll combination, a rear frame positioned behind said roll combination, an intermediate frame comprising as least me horizontal beam and extending between said front and said rear frame and above said roll combination, at least one auxiliary frame located below said intermediate frame and carrying at least one roll of said roll combination said auxiliary frame being connected by a shaft to one of said front or rear frames and arranged rotatably around said shaft, and locking means provided on said intermediate frame and corresponding locking means provided on said auxiliary frame for detachably interlocking said auxiliary frame to said intermediate frame, during the operating process of the press, connecting means provided on said front and rear frames and corresponding connecting means provided on said intermediate frame for detachable interconnecting said intermediate frame to said front and rear frames. Constructions of this type are known from US patent 4,450,630 and describe a press section, in which the upper side frame members are always above the roll combination. This construction is a so-called cantilever support. A drawback is that for changing the felts, the parts between one upper side frame member and the front and rear frames should be removed, otherwise the whole construction is above the press section during the service, which is very unpractical. Also Beloit Corporation has proposed the so-called "FLIP-TOP"-frame construction. In this construction, a two-piece intermediate frame is disposed above the press section of the paper machine to connect the front and rear frames of the press section. During the operation of the press section, the ends of the intermediate frame are fixed both to the front and the rear frame. Either of these attachments can be detached and the detached portion of the intermediate frame can be pivoted into the centre of the intermediate frame, around the transverse articulated shaft of the paper machine. The partial opening of the intermediate frame has the purpose of facilitating the felt exchange on the press section. The FLIP-TOP"-frame construction does not essentially improve other functions relating in particular to the service or operability of the press section. Valmet Oy has proposed several frame constructions of the press section. The so-called SYM-PRESS (resistered trade mark) press section is known, in which horizontal beams providing a solid connection of the front and rear frames of the press section are disposed above the press rolls in a compact press section, both on the service and the driving side of the paper machine. This kind of solution is difficult in particular with regard to the services of the press section, since the beams, being stationary above the press section, hamper and delay the service operations. The further development of this frame construction has resulted inthe solutions described in the FI-A-70951 and FI-A-73025 of Valmet Oy. These publications disclose intermediate frame constructions, in which a one-piece intermediate frame is pivotally articulated to the rear frame of the press section and disposed to be detachably fixed to the front frame, or alternatively, the intermediate frame consists of two pieces, the pieces being articulated into the front frame on the one hand and into the rear frame on the other hand. The free ends of the pieces of the intermediate frame are disposed to be fixed to the fixed intermediate part of the intermediate frame. The intermediate frames described above are pivotable around their articulating points in the vertical plane partly away from above the roll arrangement of the press section in particular in view of service operations. It is difficult to make this type of constructions sufficiently solid and thus vibrationless. The constructor of the press section of a modern paper machine has to fulfill two opposite requirements. On the one hand, the frame construction of the press section _ the front frame, the rear frame and the intermediate frame connecting these two _ should form a sufficiently rigid construction, which, during the operation of the Press section, ensures a trouble-free operation of the press section. However, on the other hand, the compact press section, the machine elements of which _ press rolls, felts and members for guiding the web _ are very close to each other in the operating position, should, in view of the necessary repeated services of the paper machine, have a construction that allows to perform the service operations in a reasonable time. This means that the press section should be capable of being opened to a necessary extent relatively easily and the above machine elements should be easily available in such an opened position. The object of the present invention is to provide a press section that fulfille the requirements described above. The press section carried out according to the invention is rigid in the operating position and on the other hand it allows the machine elements in the press section to be easily and rapidly serviced. In order to achieve this purpose, the press section according to the invention is characterized by having transfer means for moving said intermediate frame horizontally in the longitudinal direction of the paper machine into the operating position from the service position and vice versa, in which said intermediate frame si supported by a support means connected to the frame construction for receiving the siad intermediate frame into the service position. Since the intermediate frame is made detachable and _ according to the invention _ may be transported to the area of the frame construction in a horizontal direction during the service operation, this allows the pivoting of the auxiliary frames, so the whole area above the press section is free for service operation. The invention is illustrated in the following description with reference to the enclosed drawing, with presents the press section and its frame construction as a schematic lateral view. The frame construction of the press section represented in the drawing comprises the roll combination 1, 2, 3, 4 and 5. The rolls form the three nips N1, N2 and N3. The press section further comprises members for guiding the paper web through the press section and members for guiding one or a plurality of felts 6, 7 into contact with the press section. The frame construction comprises the front frame 8, the rear frame 9 and the intermediate frame 10 connecting these two from above the press section. Since the actual structural makeup of the press section does not enter into the scope of the invention, it will not be described in detail here. It is merely noted that in the frame construction according to the invention all prior known press section solution are applicable with regard to the roll combination and the other machine elements. The intermediate frame 10 comprises one or a plurality of beams 10 disposed in the longitudinal direction of the paper machine. The intermediate frame can be disposed on both sides of the paper machine. The beams can form one integral assembly or they can be disposed separately. At both ends of the intermediate frame 10 members 11a, 12a, are provided, which are disposed to cooperate to provide an interlocking with the countermembers 11b in the front frame 8 on the one hand, and with the countermembers 12b in the rear frame 9 on the other hand. This type of interlocking members can be constructed according to principles that are clear to a person skilled in the art, and consequently their detailed construction will not be described here. Owing to the joints 11 and 12 formed by the members 11a, 11b; 12a, 12b, a rigid assembly of the frame construction is achieved in the operating position. The intermediate frame 10 is removable from above the roll combination 1 to 5. The removal is disposed to be effected essentially horizontally. In the described embodiment this displacement is performed in the longitudinal direction of the paper machine. For this purpose support means 17 are disposed in the removal direction of the intermediate frame, in the described embodiment on the level of the rear frame 9 essentially on the same height level as the intermediate frame 10, onto which support means the intermediate frame 10 is transferred when removed from the roll combination. Moreover, on the removal side of the intermediate frame 10, in the described embodiment in the rear frame 9, transfer means 18 connected with the intermediate frame 10 are disposed, by means of which the intermediate frame is transferred from the roll combination into contact with the support means 17 and vice versa. The intermediate frame construction described above is one way of implementing the present invention. In the embodiment illustrated in the drawing, the two rolls 3 and 5 included in the press section are both fixed to separate auxiliary frames 13, 14. The auxiliary frames 13, 14 are supported onto the shafts 19 and 20, which are fixed to the front frame 8 (shaft 19) and to the rear frame 9 (shaft 20). The ends of the auxiliary frames 13, 14 opposite with regard to the above points of attachment are detachably fixed to the intermediate frame (10) by the fixing members 15, 16. In addition, the felt rolls 21 and 22 are fixed to the auxiliary frames, the guide roll 21 to the first auxiliary frame 13 and the guide roll 22 to the second auxiliary frame 14. The shaft 19 of the first auxiliary frame 13 is fixed to the front frame 8 and the first auxiliary frame 13 is rotatable in the vertical plane about the shaft 19 into the open position in order to open up the press section. Correspondingly, the shaft 20 of the second auxiliary frame 14 is fixed to the rear frame 9 and the second auxiliary frame 14 is rotatable in the vertical plane about the shaft 20 in the open position in order to open up the press section. The press section can of course comprise one, two or a plurality of auxiliary frames according to the invention. The members fixed to the concerned auxiliary frame can also vary in a manner characteristic of the press section construction involved.

Claims: 1. A press section in a paper machine, comprising a roll combination (1, 2, 3, 4, 5) of at least two rolls which form at least one press nip (N1, N2, N3), for guiding the paper web through the press section and members for guiding at least one felt (6, 7) into contact with the press section; a frame construction including a front frame (8) positioned before said roll combination; a rear frame (9) positioned behind said roll combination; an intermediate frame (10) comprising at least one horizontal beam and extending between said front (8) and said rear frame (9) and above said roll combination; at least one auxiliary frame (13, 14) located below said intermediate frame (10) and carrying at least one roll of said roll combination (1, 2, 3, 4, 5); said auxiliary frame (13, 14) being connected by a shaft to one of said front (8) or rear (9) frames and arranged rotatably around said shaft; and locking means provided on said intermediate frame (10) and corresponding locking means provided on said auxiliary frame (13, 14) for detachably interlocking said auxiliary frame (13, 14) to said intermediate frame (10), during the operating process of the press, connecting means provided on said front (8) and rear (9) frames and corresponding connecting means provided on said intermediate frame (10) for detachably interconnecting said intermediate frame (10) to said front (8) and rear (9) frames, characterized by transfer means (18) for moving said intermediate frame (10) horizontally in the longitudinal direction of the paper machine into the operating position form the service position and vice versa, in which said intermediate frame is supported by a support means (17) connected to the frame construction and by means (17) in connection with the said frame construction for receiving the said intermediate frame (10) into the service position. 2. A press section in a paper machine according to claim 1, characterized in that it comprises two auxiliary frames (13, 14), the first (13) of which is fixed by a first shaft (19) to said front frame (8), and the second (14) of which is fixed by a second shaft (20) to said rear frame (9). 3. A press section in a paper machine according to claim 1, characterized in that a roll (3, 5) forming a nip with a central roll (4) of the press section is fixed to said auxiliary frame (13, 14). 4. A press section in a paper machine according to claim 1, wherein a felt guide roll (21, 22) is fixed to said auxiliary frame (13, 14).

Inventors: RANTALA, MAURI, SNELLMAN, YRJOE, Snellman, Yrjö
Applicants: OY TAMPELLA AB
Application year: 1988
Main classification: D21F3
IPC codes: D21F3