GB2154973A - Conveying through ultrasonic washing apparatus - Google Patents

Abstract

In a washing apparatus, in which the wash liquor is agitated by ultrasonic vibrations, individual articles are progressed through the wash liquor by means of a conveyor which comprises fixed-position upper and side guide and a moving lower guide or guides in the form of a continuous moving loop of chain, belt or the like 5, which includes a slack accumulator 10 arranged so that the lower guide or guides press the articles up against the upper guide as they are progressed through the bath by spaced lugs 6 attached to the lower guide or possibly by spaced lugs attached to the upper guide, where that is a chain or the like moving along a fixed path. <IMAGE>

Description

SPECIFICATION Improved conveyor system for washing apparatus The present invention relates to improvements in washing apparatus and in particular to washing apparatus in which a bath of wash liquor is agitated by ultrasonic vibrations and the articles to be washed are progressed through the bath by means of a conveyor system.

In ultrasonic washing the efficiency of the operation is considerably affected by the mass of the solid objects in the bath. Efficiency can accordingly be improved by keeping the mass of the conveyor as low as possible, consistent with other considerations such as ease of loading of the articles into the conveyor system and discharge of articles at the discharge end of the bath.

In one successful form of ultrasonic washer the conveyor system consists only of a series of fixed spaced guide rods, through which the articles are pushed, butted up against each other, by a pusher system located outside the bath.

While such a system is very satisfactory for washing many items, such as empty bottle crates, it is found that areas of dirt may be left undisturbed where the ends of the articles are flat, so that the relatively thin film of liquor lying between abutted article ends remains relatively undisturbed.

It is an object of the present invention to provide, in an ultrasonic washing bath, an improved conveyor system which will convey the individual articles through the bath in spaced-apart relation. It is a further object of the invention to provide a conveyor system which will be effective for conveying batches of articles of a wide range of vertical dimensions without requiring down time for adjustments between batches of articles of different vertical dimension.

In the system of the present invention the conveyor comprises a series of upper and side guides, which remain in essentially fixed positions during operation, the upper guide or guides being located at a level below, but preferably close to, the surface of the wash liquor, and one or more flexible driven lower guides in the form of a continuous loop of chain, belt or the like, said lower guide or guides including a slack accumulator, preferably located near the input end of the wash liquor bath. The lower guide is in most cases provided with spaced drive lugs for progressing the individual articles through the bath, although these may be provided on the upper guide or guides where these are in the form of chain, belt or the like.

The function of the slack accumulator is to provide a back tension on the lower guide as it is progressed through the bath so that the lower guide holds the articles in contact with the upper guide, yielding to such an extent as may be necessitated by the vertical dimension of the articles and drawing out slack from the accumulator as may be necessary.

One form of apparatus made in accordance with the present invention is illustrated in the accompanying figure which shows a diagrammatic side view of the apparatus.

The wash tank 1 is provided with conventional ultrasonic vibrators (not shown). The tank is fitted with upper stationary guide 2 or alternatively a moving upper guide 2' in the form of belts or chain (shown in dotted lines) and is arranged at its ends to provide inlet and outlet openings 3 in the cover casing of the tank. As will be seen the middle section of the upper guide 2 or 2' lies beneath the surface of the wash liquor in tank 1.

The moving lower guide 4 preferably comprises a single chain 5, carrying spaced, laterally extending drive lugs 6. In some instances a pair of spaced chains, interconnected by drive lugs, may be employed.

The lower guide chain 5 is driven by a drive sprocket 7 at the outlet end of the tank and passes over idler 8 at the inlet end of the tank, returning from the drive sprocket underneath the tank via idlers 8 and 9 and slack accumulator 10. In its simplest form the slack accumulator 10 comprises a pivoted lever arm 11, carrying idlers 12 and 14 and weighted so as to tilt towards the pulley 14. In another form one of the idlers 12 or 14 is mounted on a fixed spindle and the other on a spindle which moves in a vertical guideway against a restraining force.

The slack accumulator is shown in the drawing in the position where the guide chains lie in their upper full-line position (corresponding to an absence of any article in the wash tank).

When articles 15 delivered by a feed con- veyor 16, are inserted through the inlet opening 3, each is engaged by a drive lug 6 and is carried forward against the descending portion of the upper guide 2 or 2'. This deflects the guide chain 5 downwardly to the lower chain line position and lever arm 11 pivots counter clockwise to release slack to compensate for the deflection of the lower guide chain.

In this way batches of articles 15 may be passed through the tank and be held pressed up against the upper guide 2 or 2', provided that the articles in the batch are of substantially constant vertical dimension. It will be readily be seen that the apparatus can readily accept batches of articles, which may lie in wide range of vertical dimensions, for delivery to an unloading conveyor 17.

Although not shown in the drawing stationary side guides are preferably provided to prevent lateral wandering of the articles under treatment. The stationary side guides are preferably adjustable to compensate for articles of different width.

Where the upper guide is in the form of chains 2' or the like, it passes round a drive sprocket 20, idler 21 and other guide rolls, not shown,-which are effective to make it follow a path adjacent the surface of the liquor in the tank. As already indicated, in this alternative the drive lugs 5 may be on the upper guide 2' and be omitted from the lower guide 4. However it is preferred that the drive lugs be on the lower guide.

It is in fact preferred to use stationary upper guides 2 and moving lower guides 4, since in such an arrangement there is a total absence of submerged spindles and bearings for rotat ing parts.

The conveyor system is very convenient for washing a wide variety of objects. The drive lugs maintain the articles in spaced-apart con dition during transit through the wash tank.

That permits penetration of ultrasonically vi brated liquor into the space between the ends of adjacent articles; also jets of rinsing liquor.

The arrangement allows individual articles, such as containers, trays or boxes to be carried through the wash tank either in normal position or inverted. It also permits batches of relatively deep containers and batches of rela tively shallow covers or lids for the same to be treated without any requirement for intermedi ate adjustment of the guides.

As compared with earlier forms of washing apparatus in which the articles are progressed through the wash tank by means of a moving conveyor, in the apparatus of the present invention, there are no idler rollers or like restraining means to define the path of the lower guide through the wash tank so that any portion of the lower guide is free to rise when not prevented by an article in the course of transport through the tank. The absence of idler rollers is advantageous both because there is less mass within the liquor to cause attenuation of the supersonic vibration and because the absence of idler rollers or their equivalents reduces the number of items which may undergo attack by the hot wash liquor.

Claims (1)

1. CLAIM

   1. A washing apparatus comprising a bath of wash liquor which is agitated by ultrasonic vibrations and having a conveyor system for conveying individual articles through the bath in spaced-apart relation characterised in that the conveyor comprises upper and side guides which remain in essentially fixed positions during operation, the upper guide or guides being located at a level below the surface of the wash liquor, and one or more flexible driven lower guides in the form of a continu ous loop of chain, belt or the like, said lower guide or guides being located beneath the upper guide or guides and including a slack accumulator, whereby tension applied to the lower guide or guides is effective to hold articles of different heights in contact with the upper guide or guides during progress through the bath.