GB2247032A

GB2247032A - Apparatus for manufacturing single-faced corrugated board

Info

Publication number: GB2247032A
Application number: GB9021078A
Authority: GB
Inventors: Graham Critchlow
Original assignee: Simon Container Machinery Ltd
Current assignee: Simon Container Machinery Ltd
Priority date: 1990-07-13
Filing date: 1990-09-27
Publication date: 1992-02-19
Anticipated expiration: 2010-09-27
Also published as: GB2247032B; GB9021078D0

Abstract

Single-faced corrugated board apparatus comprises a pair of inter-engaging fluted corrugating rolls (10, 11), a glue applicator mechanism (15, 16, 17) to place glue on the tips of the corrugated board passing around corrugating roll (11), a pressure roll (12) delivering a linear sheet (18) for combination with the corrugated sheet (at 19). Pressurised air from a source (21) is fed separately to two plenum chambers (20, 24), and valves (26, 27) are provided to establish a slightly high pressure in plenum chamber (24) than that in chamber (20) such that a passage of air flows upwardly through a gap (23) between the chambers to prevent spill age of glue. <IMAGE>

Description

APPARATUS FOR MANUFACTURING S INGLE - FACED CORRUGATED BOARD THIS INVENTION concerns apparatus for manufacturing single-faced corrugated board.

Such board is made by passing a first continuous paper web around a pair of inter-engaging fluted rolls, through the nip thereof, to produce transverse corrugations in the paper. During its passage around the second corrugating roll, the peaks of the corrugations on the paper are coated with glue by contact with a glue applicator roll positioned over a glue tray. The corrugated sheet is then joined with a liner board by passing the pair through the nip of a pressure roll with the second corrugator roll whereupon the liner board is glued to the tips of the corrugated board and the product issues from the nip.

It has been found that there is a tendency for the corrugated board to leave the fluted surface of the second corrugating roll during its passage towards the glue roll, and many systems have been tried to overcome this problem, including the provision of a pressurised air chamber effective against the surfaces of at least a part of the corrugator roll pair and around part of the pressure roll thus enclosing also the gluing mechanism.

Since it is impossible to render the chamber entirely airtight where it abuts the rotating surfaces of at least two of the rolls, such devices have suffered from the disadvantage that turbulence is created within the chamber causing the glue to spill out of its containment tray.

An object of the present invention is to provide apparatus of this kind wherein the difficulty of turbulence is avoided.

According to the present invention there is provided, apparatus for manufacturing single faced corrugated board comprising a pair of inter-engaging fluted corrugating rolls, a glue applicator mechanism comprising a glue tray and a roll to apply glue to the peaks of a corrugated paper sheet issuing from a nip between the corrugating rolls, and a pressure roll around which passes a liner sheet which forms, with the corrugated sheet, a single-faced board as it passes through a nip between the pressure roll and one of said corrugating rolls, characterised by the provision of a first plenum chamber to which pressurised air is supplied to be effective against at least a part of the fluted surface of each corrugating roll, and which encloses the glue applicator mechanism, and a second plenum chamber supplied with pressurised air to be effective against at least a part of the surface of said pressure roll, the supplies of pressurised air to said first and second plenum chambers being relatively adjustable thus to balance the pressures within said chambers and, if required, to provide a pressure differential therebetween.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying schematic drawing which illustrates a machine for producing a single-faced corrugated paper board. The machine consists essentially of first and second fluted corrugating rolls 10 and 11 combined to form a nip therebetween, and a pressure roll 12 combined with the second corrugating roll 11 to form a further nip therebetween. In the manufacture of corrugated paper board, a first continuous sheet 13 is passed over a steam box 14 to precondition the paper and then through the nip between the fluted rolls 10 and 11.

A glue applicator roll 15 takes up glue from a tray 16 in a controlled manner by means of a doctor roll 17 and applies the glue to the tips of the corrugated paper as it passes around roll 11.

A continuous liner sheet 18 is introduced around pressure roller 12 and forms, in the nip between the latter and second corrugating roll 11, the single faced corrugated board by combining it with the glued and fluted sheet 13. The product board issues as indicated at 19 from the nip.

A first plenum chamber enclosed by a housing 20 is effective to apply pressurised air from a source 21 to a part of the circumference of each of the two corrugating rolls 10 and 11.

The housing 20 is designed to permit controlled leakage of air at 22 against the rotating face of roll 10, and at 23, against the rotating face of roll 11 where a gap of some 5mm may be present.

The housing 20 encloses the glue mechanism 15, 16, 17.

A second plenum chamber is formed by a housing 24 which is sealed against a roller 25 forming a nip with pressure roller 12, and is combined at 23 with the housing 20. It will be seen that the plenum chambers 20 and 24 are supplied via separate valved ducts 26 and 27 respectively, so that the pressures in the two plenum chambers may be balanced as required.

The overall pressurised air is supplied at approximately 450mm water gauge.

For effective operation, the valved ducts 26 and 27 are adjusted such that the pressure in the lower plenum chamber 24 is maintained at a slightly higher level than that in plenum chamber 20, the pressure differential being in the range 5mm - 20mm water gauge.

This has the effect of creating a continuous passage of air from chamber 24 to chamber 20 thus preventing any turbulence in the glue tray 16 and any tendency for the glue to splash into the zone 23.

It will be appreciated that if the pressures were equalised or reversed then any leakage of air, might tend to cause the glue to spill over the edge of the tray 16 at its position closest to roll 11. The continuous air flow upwardly at 23 prevents this.

In practice, ducted valves 26 and 27 may be fine tuned to ensure minimum pressure differential between the plenum chambers commensurate with clean efficient operation with no spillage of the glue.

Pressure gauges 28 and 29 are provided so that the operator may monitor the pressures in the two chambers.

Claims

1. Apparatus for manufacturing single faced corrugated board comprising a pair of inter-engaging fluted corrugating rolls, a glue applicator mechanism comprising a glue tray and a roll to apply glue to the peaks of a corrugated paper sheet issuing from a nip between the corrugating rolls, and a pressure roll around which passes a liner sheet which forms, with the corrugated sheet, a single-faced board as it passes through a nip between the pressure roll and one of said corrugating rolls, characterised by the provision of a first plenum chamber to which pressurised air is supplied to be effective against at least a part of the fluted surface of each corrugating roll, and which encloses the glue applicator mechanism, and a second plenum chamber supplied with pressurised air to be effective against at least a part of the surface of said pressure roll, the supplies of pressurised air to said first and second plenum chambers being relatively adjustable thus to balance the pressures within said chambers and, if required, to provide a pressure differential therebetween.

2. Apparatus according to Claim 1, wherein said first plenum chamber is enclosed by a housing designed to permit controlled leakage of air between parts of the housing wall and the rotating faces of the two corrugating rolls.

3. Apparatus according to Claim 1 or Claim 2, wherein said second plenum chamber is enclosed by a housing sealed with respect to the pressure roll, and designed to permit controlled leakage of air from the housing against the rotating face of the one of said corrugating rolls which forms a nip with the pressure roll.

4. Apparatus according to any preceding claim, wherein there exists a gap of some 5mm between the first and second plenum chambers and the one of said corrugating rolls which forms a nip with the pressure roll, such that a controlled leakage of air may flow between said plenum chambers, through said gap.

5. Apparatus according to any preceding claim, including a pressurised air source communicating, via a pair of separate valved ducts, respectively, with said first and second plenum chamber.

6. Apparatus according to Claim 5, in which said pressurised air source provides an air pressure of approximately 450mm water gauge.

7. Apparatus according to any preceding claim, when operating with a pressure differential between the second plenum chamber and the first plenum chamber with the second plenum chamber at the higher pressure.

8. Apparatus according to Claim 7, wherein said pressure differential is in the range 5mm to 20mm water gauge.

9. Apparatus according to any preceding claim, including pressure gauges adapted to provide an indication of the air pressures separately within said first and second plenum chambers.

10. Apparatus for manufacturing single faced corrugated board, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.