Base Plate for Pulp Moulds
The application discloses a base plate comprising a rigid body portion ( 50 ), means ( 51, 52′, 52″ ) arranged within the rigid body portion ( 50 ) to enable vacuum to be applied. The vacuum means comprise an open space ( 51 ) in the form of a centrally positioned recess forming a vacuum chamber ( 51 ) within the rigid body portion ( 50 ) and at least one connecting channel portion ( 52′, 52″ ) that extends in the main plane of the rigid body portion ( 50 ) arranged to connect the vacuum chamber ( 51 ) with a vacuum source ( 52 ). An assembly comprising the base plate and a pulp mould, as well as methods for producing the base plate and the assembly, are also disclosed.
1 . A pulp mould base plate, comprising a rigid body portion ( 50 ) and means ( 51 , 52 ′, 52 ″) within said body portion arranged to enable vacuum to be applied to a pulp mould, characterized in that said vacuum providing means comprises an open space ( 51 ), in the form of a centrally positioned recess, forming a vacuum chamber ( 51 ) within said body portion ( 50 ) and at least one connecting channel portion ( 52 ′, 52 ″), that extends in the main plane of the rigid body portion ( 50 ) arranged to connect said vacuum chamber ( 51 ) with a vacuum source ( 52 ).
2 . The base plate according to claim 1 , characterized in that said vacuum chamber ( 51 ) at the rear side ( 57 ) of said base plate ( 50 ) is sealed off by means of an integral layer ( 570 ) of said base plate body.
3 . The base plate according to claim 1 , characterized in that said vacuum channel ( 52 ′, 52 ″) is at least partly arranged as a rearwardly open channel ( 52 ′) at rear side ( 57 ) of said body portion ( 50 ).
4 . The base plate according to claim 1 , characterized in that said body portion ( 50 ) includes a plurality of vacuum chambers ( 51 ).
5 . The base plate according to claim 4 , characterized in that said plurality of vacuum chambers ( 51 ) are arranged with a common supply channel ( 52 ′) or common portion of said channel ( 52 ′), preferably said supply channel, or channel portion ( 52 ′) is in the form of at least one drilled bore ( 52 ′).
6 . An assembly of a base plate according to claim 1 , characterized by said pulp mould ( 10 ; 20 ), comprising a porous sintered body ( 11 ) having an outer surface ( 13 ) and an inner surface ( 12 ), wherein a limited area ( 14 ) of said inner surface ( 12 ) is machined providing a mating support surface ( 14 ) to interfit with a support surface ( 55 ) of said body portion ( 50 ).
7 . An assembly according to claim 6 , characterized in that an unmachined portion of said inner surface ( 12 ) of the pulp mould protrudes into said vacuum chamber ( 51 ) to a level below the plane of said support surface ( 55 ).
8 . An assembly according to claim 6 , characterized in that said machined surface ( 14 ) extends in one and the same plane, preferably said machine surface ( 14 ) extends from the outer side edges of the mould into inner portions.
9 . A method for producing a pulp mould base plate comprising the steps of providing a rigid body portion ( 50 ) and means ( 51 , 52 ′, 52 ″) within said body portion arranged to enable vacuum to be applied to a pulp mould, characterized by arranging said vacuum providing means to comprise an open space ( 51 ) forming a vacuum chamber ( 51 ) within said body portion ( 50 ) and arranging at least one connecting channel portion ( 52 ′, 52 ″), that extends in the main plane of the rigid body portion ( 50 ) to connect said vacuum chamber ( 51 ) with a vacuum source ( 52 ), preferably by sealing off said vacuum chamber ( 51 ) at the rear side ( 57 ) of said base plate ( 50 ) by means of an integral layer ( 570 ) of said base plate body.
10 . A method for producing a base plate according to claim 9 , characterized by arranging at least partly said vacuum channel ( 52 ′, 52 ″) as a rearwardly open channel ( 52 ′) at rear side ( 57 ) of said body portion ( 50 ).
11 . A method for producing a base plate according to claim 9 , characterized by arranging said body portion ( 50 ) to include a plurality of vacuum chambers ( 51 ).
12 . A method for producing a base plate according to claim 11 , characterized by arranging said plurality of vacuum chambers ( 51 ) with a common supply channel ( 52 ′) or common portion of said channel ( 52 ′), preferably by arranging said supply channel, or channel portion ( 52 ′) to be in the form of at least one drilled bore ( 52 ′).
13 . A method for producing an assembly of a base plate according to claim 9 , characterized by arranging said pulp mould ( 10 ; 20 ) to comprise a porous sintered body ( 11 ) having an outer surface ( 13 ) and an inner surface ( 12 ), machining a limited area ( 14 ) of said inner surface ( 12 ) thereby providing a mating support surface ( 14 ) to interfit with a support surface ( 55 ) of said body portion ( 50 ).
14 . A method for producing an assembly according to claim 13 , characterized by protruding an unmachined portion of said inner surface ( 12 ) of the pulp mould into said vacuum chamber ( 51 ) to a level below the plane of said support surface ( 55 ).
15 . A method for producing an assembly according to claim 13 , characterized by extending said machined surface ( 14 ) in one and the same plane, preferably said machine surface ( 14 ) is extending from the outer side edges of the mould into inner portions.