Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates -to an apparatus for the application
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of coating materials in a liquid state to a moving web of the kind
where the liquid is applied to the surface of the web through a
porous member.
~ When coating webs it is often desirable to use the same ap~
-~- paratus to coat webs of different widths and the object of the in-
vention is to provide means by which the width of the coating head
, can be varied to suit different widths of web to be coated.
According to this invention we provide a coating head com-
` 10 prising a porous member having at least one row of pores, the saidmember being provided between a reservoir of liquid and the web to
be coated, the porous member including a bore e~tending at right
angles to the pores and intersecting the pores in the porous mem-
- ber, a deckle rod being provided to slide within the bore and
adapted to make a precision fit therewith thereby closing the pores
with which it is in contact. The said bore may be provided in a
tube fast with the end wall of the reservoir, both the tube and
, the end wall being drilled to provide the pores of the porous mem-
ber. The effective width of the head of the porous member can be
adjusted by pushing or withdrawing the rod into or from the bore.
Preferably the bore is accessible from each end of the porous
member.
The or each deckle rod may be constructed with a slot along
its length and this lot may be filled with a resilient material.
The purpose of this is that when the rod is inserted into the bore
the resilient material urges the surface of the rod into contact
with the sides of the bore thereby sealing the openingsin the pores.
One form of apparatus for carrying out the present inven-
` tion is illustrated in the accompanying drawing, wherein:-
Fig. 1 is a sectional front elevation;
` Fig. 2 is a sectional side eleva-tion, and
Fig. 3 is a detail view.
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~ eferring -to the drawing, the coating head comprises a
hollow member having side walls 2 and 3 and an end or bottom wall
4 providing a chamber 6 forming a reservoir for the coating liquid.
A length of metal tubing 8 is welded as indicated at 9 to the
bottom wall 4 and the wall 4 and tube 8 are together drilled so
as to form a single row of pores 10 uniformly spaced along the
length of the member interrupted by the hollow interior of the
tube 8. Fig. 3 is a detail view showing the lower part of the
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chamber 6, the end wall 4, the tube 8 and the drilled pores 10.
',-10 A horizontal bore 12 is drilled through each of the side walls 3,
these bores 12 being in line with the ends of the tube 8 so that ~ -
the bores 12 and the tube 8 form a continuous bore through the
head. Deckle rods 14 are adapted to make a precision fit in the
bore, one deckle rod 14 being provided for each end. Each deckle
rod 12 has a longitudinal slot 16 filled with silicone rubber 18
or other resilient material to ensure that the surface of the rod
14 is pressed outwardly against the internal surface of the tube 8
so that the pores 10 are effectively closed when the rod is pushed
into the tube 8. In this way the rod 14 is compressed to form a
tight seal across any pore at which it is adjusted to cross
axially. At the inlet to each bore 12, a split collar 15 is fixed
to the wall 3 and a clamp 17 is provided to be screwed up tightly
around the collar 15 to prevent accidental alteration of the posi-
tion of the deckle rod during coating.
A handle 19 is provided at the end of each deckle rod.
This handle is aligned with the slot 16 in the deckle rod and
' therefore serves to indicate the position of the slot in relation
to the drilled pores.
The web 20 is supported in the correct position adjacent
to the porous member by an air supported belt 22. High pressure
air passes through the apertures 24 in a box 26 to support the
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' belt 22. When the effective width of the porous member ls re-
duced by the deckle rods 14 it is also necessary to blank off the
rj air support jets 27 on the lower surface of the belt 22. This is
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`~; done by means of a masking s-trip 28 which can be slldden into
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'~ brackets 30 provided at the two ends of the top of the box 26.
A smoothing bar 32 of suitable length is used to suit the width
of the web. The upper part of the chamber 6 is provided with a
, filter 34 the edges of which are located in recesses 36. A
: sealing gasket 38 is provided for contact with the filter 34.
Instead of the tube 8, the lower end of the chamber may
be filled with metal and the horizontal bore is made through the
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metal. The pores 10 are drilled through the metal and the end
wall 4.
Although the invention has been described with reference
to an apparatus where the web moves horizontally, the invention
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`~ can also be applied to an apparatus where the web moves vertically.
- An apparatus to which the present invention can be applied is
described in our Canadian Patent Specification 908,974 or our
U.K. Patent Specification 1,423,823.
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