Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F3/00—Press section of machines for making continuous webs of paper
  • D21F3/02—Wet presses
  • D21F3/0209—Wet presses with extended press nip
  • D21F3/0218—Shoe presses

Definitions

• the invention relates on the one hand to a method of supporting a press shoe in a shoe press and, on the other hand, to a shoe press.
• the invention concerns a shoe press for a paper or board machine, said shoe press having a press shoe which together with a counter roll forms an extended nip for a paper or cardboard web and for a flexible circulated belt, and at least one piston-and-cylinder assembly, which is arranged between a supporting beam associated with the frame system of the shoe press and the press shoe and in which hydraulic fluid is supplied to a working chamber, said working chamber communicating with a compartment via a throttle, said compartment being arranged on the outside of the piston-and-cylinder assembly in such a manner that the hydraulic fluid therein exerts directly or indirectly a force upon the press shoe in the direction opposite to that of the force exerted upon the press shoe by the hydraulic fluid in said working chamber.
• a shoe press as described above is disclosed in
• This prior-art shoe press suffers from the drawback that lateral forces which in operation affect the press shoe are transmitted to the cylinder jacket and the piston, which may cause a jam between the press shoe ' and the piston.
• the object of the invention is to eliminate this drawback.
• the drawback implying that lateral forces which in operation affect a press shoe are transmitted to the cylinder jacket and the piston has been eliminated by a new method of supporting the press shoe, said method having the characteristic features as defined in claim 1.
• Advantageous embodiments are stated in the subclaims.
• Fig. 1 is a cross-sectional view of a first embodiment of the shoe press according to the invention
• Fig. 2 is a cross-sectional view of a second embodiment of the shoe press according to the invention
• Fig. 3 is a cross-sectional view of a third embodiment of the shoe press according to the invention.
• FIGs 1 and 2 designates two embodiments of a shoe press and reference numerals 2, 3, 4 designate a press shoe, a piston and a cylinder, respectively.
• the cylinder 4 and the piston 3 which is movingly arranged therein define a chamber 5, to which a hydraulic fluid, e.g. oil, is supplied from a duct 6 in the piston 3 via one or more bores 7 in the piston 3.
• a radial seal 8 is arranged for the sealing of the chamber 5.
• the piston 3 is slightly tiltable in the cylinder 4.
• Reference numeral 9 designates a horizontal support- ing beam located in the shoe press and fixed to the frame.
• the piston 3 is fixedly connected to the press shoe 2, and the end wall of the cylinder 4 rests freely on the beam 9, while in the embodiment according to Fig. 2, the piston 3 is fixedly connected to the beam 9 and the press shoe 2 rests freely on the end wall of the cylinder .
• bolts 10 The flexible press belt of the shoe press is designated 11, and the counter roll of the shoe press is designated 12.
• a through throttle 14 which opens into a shallow compart- rr.ent or pressure chamber 15 in the end wall of the cylinder 4. Hydraulic fluid in the chamber 5 may thus escape to this compartment via the throttle 14.
• the area of the compartment 15 is somewhat larger than the inner area of the cylinder 4, which causes the lifting force exerted upon the press shoe 2 by the hydraulic fluid in the compartment 15 at an initial stage of the operation to be greater than the force exerted upon the press shoe 2 by the hydraulic fluid in the working chamber 5. This results in the forming of a gap 16 between the annular bottom surface 4' of the cylinder 4 and the beam 9
• Fig. 3 illustrates a shoe press having a press shoe 300, a counter roll 312, a circulated press belt 311, a piston-and-cylinder assembly 310 with piston 330 and cylinder 340, and a beam 309 which is fixed to the frame.
• the piston 330 is attached to the beam 309 by means of bolts 350.
• the top face of the movable cylinder 340 adjoins the press shoe 300, and in this top face there is a compartment or hydraulic fluid chamber 301, which is defined by an annular flange with an annular surface 340' on the top of the cylinder 340.
• the compartment 301 is supplied with hydraulic fluid via a sectional pipe 303 which is attached to the longitudinal side edge 304 of the press shoe 300 and which has an inner duct 306, via a bore 302 formed in the press shoe 300 and having bore portions 302' and 302" which are perpendicular to each other, and an opening 308 which is formed in the sectional pipe 303 and constitutes a throttle.
• a sectional pipe 303 which is attached to the longitudinal side edge 304 of the press shoe 300 and which has an inner duct 306, via a bore 302 formed in the press shoe 300 and having bore portions 302' and 302" which are perpendicular to each other, and an opening 308 which is formed in the sectional pipe 303 and constitutes a throttle.
• the working chamber 325 of the piston-and-cylinder assembly 310 is supplied with hydraulic fluid, like in the embodiments above, via a duct system 326, 327 in the piston 330.
• the inventive shoe press is applicable also to calendering operations in a paper or board machine.

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• Paper (AREA)

Applications Claiming Priority (3)

Publications (1)

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Family Applications (1)

Country Status (3)

Families Citing this family (5)

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• 1997
  • 1997-09-30 SE SE9703570A patent/SE510552C2/sv not_active IP Right Cessation
• 1998
  • 1998-09-30 WO PCT/SE1998/001758 patent/WO1999016967A1/en not_active Application Discontinuation
  • 1998-09-30 EP EP98946769A patent/EP1027488A1/de not_active Withdrawn

Non-Patent Citations (1)

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