GB2211217A

GB2211217A - Adjusting slot length of slot in suction box top

Info

Publication number: GB2211217A
Application number: GB8724401A
Authority: GB
Inventors: Michael John Morley
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-10-19
Filing date: 1987-10-19
Publication date: 1989-06-28
Also published as: GB8724401D0

Abstract

The slot length of a slot in a suction box top is adjusted by means of an adjustable bar or deckle seal 2 during normal operating conditions. The top of the bar or deckle seal may be provided with a length scale to enable the operator to determine the extent of the bar or deckle seal covered by wire, fabric, or felt. <IMAGE>

Description

improvements in or relating to paper macing machinery This invention relates specifically to support surfaces especially for paper making machine vacuum or suction boxes.

Vacuum or Suction Boxes are a necessary part of tne paper making machine, and their purpose is to remove water from a moving wire, fabric or felt as it travels past a slot or slots in tne contacting surface of the commonly stationary vacuum or suction oox, tnro aitferential air pressure that creates an air flow through the wire, fabric or feit, which tnen transfers water from the said wire, fabric or felt into tne vacuum or suction box.

The vacuum or suction box assembly also serves to support tne wire, fabric or felt, to prevent its distortion whilst passing the vacuum slot or slots. ihe box structure will be so resigned as to be supported at each side of the paper machine on framing or subframing and will be sufficiently rigid to maintain a level surface across tne paper machine.

Toe box location will be such that tne slotted surface wiii be in level contact with the wire, fabric or felt. The wire, fabric or felt will normally travel at ninety degrees to the slot air flow but this may be varied. The wire, fabric or felt can travel in any degree of angle at or from the horizontal.

The box may be required to dewater or reduce the water content of the wire, fabric or felt, and it may also be required to remove water from a sheet of paper that may be over the wire, fabric or felt.

The box may for a wire or fabric appsic llon also oe known as a slat Box, and for a fabric or lelt application aiso be tnown as a Conditioning Box or by the acceptabie generic term as a uncle Box.

The Vacuum or Suction Box assembly is commonly manufactured from stainless steel, either as a fabrication from sheet material or constructed from tube or pipe material The assembly will commoniy operate with an internal vacuum in the range between 100 mm water column and 5500 mm water column, but some exceptions can be outside tnese limits.

The swotted surface of the box that contacts the wire, fabric or felt is commonly manufactured from plastic or from ceramic material, or from a combination of different materials that are compatibie witn the needs of the wire, fabric or welt, or the sheet of paper.

The sots will in tne paper machine running direction commonly range between 6 mm and 30 mm, but may also be outside these limits. ln the direction across tne paper machine they will normally extend to or beyond the limits of the design width of the wire, fabric or felt.

Each box may have one slot or a number of slots.

To maintain a vacuum in the box the slot ends are commonly sealed with an adjustable bar commonly called a deckle seal. The bar can be moved into or withdrawn from the slot sufficiently so that the inside end of each bar provides the vacuum slot end to coincide with the width requirements of the wire, fabric, felt or sheet of paper. By this method leakage of air around the end of the area to be dewatered can be prevented which would otherwise cause loss of vacuum ana reduction ci watering efficiency. This arrangement has Deen in common use for many years.

There is however an operating problem in existence with this arrangement, because in many situations the position of the inside end of the adjustable bar or deckle seal cannot be seen. This is because the wire, fabric or felt, or the paper sheet covers the box structure so that the adjustable slot end location cannot be located whilst the paper machine is in operation. lt is thus common to fin that the bar inside end is in the wrong position.

The result of this deficiency is that the watering effect can be different at the ends resulting in operational problems including uneven contamination of wire, fabric or feit.

Specific embodiments of the invention will now be describe by way of example with reference to the accompanying drawings n which Fig 1 snows, in perspective, a single slotted box top with its adjustable bar in place, and a wire, fabric or felt passing over it to illustrate that the inside limit of the bar cannot be seen.

Fig 2 shows, in perspective, the same situation as in Fig 1 but without the wire, fabric or felt in place, to show the inside limit of the bar.

Pig 3 shows, in perspective, a common adjustabie bar or deckle seal.

Fig 4 shows, in perspective, an adjustable bar or aecF e seal modified to embody the invention.

Fig 5 shows, in perspective, the invention in place from which can be found tne exact position of the inside bar or seai end Fig 1 shows, in perspective view, a typicai slotted vacuum or suction box top(l) incorporating a singie slot with the adjustable bar or deckle slot snown (2). Whist this is the most common arrangement there may be two or more slots The view shows the wire, fabric or resit (3) travelling in one of the directions shown (4) which also iiiustrates that the inside end of the bar or aecie cannot be seen (S') or often cannot be iocated.

Fig 2 shows, in perspective view, the same view as in Fig i but in a non operational mode to illustrate the inside slot end(6) and the slot (7).

Fig 3 shows, in perspective view, a common type of bar or seal (2). The actual design or shape (s) must however conform to the particular design or shape ol the actua support surface bars (1) shown in Fig í to effect a vacuum seal. There are many different configurations of support bars.

The present invention involves an effective means of measuring the extent of penetration of the adjustable bar or deckle seal(2) along the slot whilst the paper machine is in operation and whiist the inside bar or seal end cannot be located.

The adjustable bar shown in perspective view in Fig 4 is clearly marked (8) normally in centimetres, although other measures can be applied. The markings which are cut into tne surface oi the bar or seal are measured from the inside end of tne bar or sea (9) to the outia end on each side of the box.

The adjustable bar or deckle seal length (2) will be determined by the require minimum operational width for the slot (7) shown in Fig 2.

In Fig 5 the invention can be seen in place with the wire, fabric or felt over the slot thus normally preventing tne location of the inside adjustable bar or ecie seal eno.

The invention now allows a simple method of establishing the exact location of the inside end of tne adjustable bar or deckle seal. The figure level with the end of the slotted surface (10) can be read and a ruier or tape can then be held over the bar or seal the same aistance in as the bar reaiing. one inside end wiii now be ocatec at (íí) and a aetermination of its positions suitaoility can then be maae. Ine bar or seal can ten be adjusted in or out to tne correct position ior maximum effect and beneiit.

There may be one or more Slots in each vacuum or suction box and these may embody individual bars or deckles or alternatively a combined assembly to move all seals in and out together. Alternatively there may be a combination of the two aiternative methods.

As an alternative to the method of marking the bar or seal described and shown in Fig 4 the markings may commence from a point within the surface structure, for example from the normai edge position of the wire, fabric or felt, or from any point.

The principies shown in Figs 4 and 5 can aiso be applied to other needs in other parts of the paper making machine or to other types of paper, board or pulp making macnines or to otner processes witnin or outside the paper industry that require such means of identification emboaien in te invention

Claims

CLAIMS : 1. A surface vacuum slot in a paper making machine or other machine which can be definatively aåjústed for slot open length during norma operating conditions.
2. An adjustable bar or deckle seal that is marked so that its inside position can be located during normal operating conditions.
3. A means of positioning a bar or deckle in claim 2 to achieve a particular slot open iength as in ciaim 1.
4. A surface substantially as herein described with reference to anc as illustrated Dy rigs 4 and 5 of tne accompanying arawings..
5. A paper making machine or otner machine or devise including bars or heckles as claimed in any one of ciaims 1, 2, 3 or 4.