GB2188255A - Tankwasher - Google Patents

Abstract

A tankwasher which may be mounted in a tank that requires cleaning comprises a tube 1 connected to a source of cleaning liquid supply, a shaft 5 non-rotatably mounted in the outlet end of the tube 1 and having an enlarged head at its lower end, a liquid guide 3 surrounding said shaft 5 internally of the tube 1 and formed with helical grooves on its external surface, and a shaped liquid distribution disc 4 rotatably mounted around the shaft 5. An R-shaped resilient clip 2 connects the shaft 5 to the tube 1 and, upon its removal, the shaft 5, the liquid guide 3 and the disc 4 can all be freely removed from the tube 1 for cleaning. The rotatable disc 4 comprises apertures 9 interconnecting its opposite sides and produces fan-shaped sprays of liquid at each side of its plane of rotation. A chamber 6 formed between the head of the shaft 5 and the disc 4 is connected by an annular passage 7 to the source of liquid supply and, during use, the fluid pressure in the chamber 6 counterbalances that acting upon the disc 4 thus facilitating free rotation of the disc 4. <IMAGE>

Description

SPECIFICATION Tankwasher Within the milk, food and drug industries there are many tanks of relatively small size containing liquid. It is important for hygienic reasons that these tanks should be cleaned out regularly and that this should be done with an assurance that the qua I ity of the cleaning process is reliable.

It is now common practice to clean such tanks using relatively small tankwashers placed permanently or semi-permanently inside the vessels. Since these tank washers clean-in-place they are known by the name, C.l.P. Tankwashers. These C.l.P. Tankwashers are rotating devices which, when supplied with a liquid under pressure, distribute an even spray ofthat liquid overtheinternalsurfaceofthetank.Thesupplyofthe liquid could be adjusted bya control system in such a way that a pump delivers a mixture of rinsing water, detergent solution and a sterilentas a final wash.

It is importantthat a tankwasherforthis purpose should be simple, reliable and be able to be dismantled with ease by the operator. Since all parts ofthe system that clean the tank need themselves to be cleaned, it is necessary thatthe tankwasher itself should be taken apartatregular intervals, and that its individual parts should be washed in a detergent solution.

Atankwasher in accordance with the invention is constructed so that it can easily be dismantled by an operatorwithouttools and having little mechanical knowledge.

The ta nkwasher is mou nted within the tank to be cleaned, is fixed in place and is connected by an external pipeto a pump andtanksystem supplying the cleaning and rinsing liquids. The tankwasher can be immersed in the liquid product contained in the tank without damage and without contaminating that product.Thetankwasherusesnolubricantotherthan the cleaning solution.

For a better understanding ofthe invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which Figure 1 is an external elevation of a tankwasher in accordance with the present invention, Figure 2 is a section taken on the line ll-ll in Figure 1, Figure 3 is a sectional plan viewtaken on the line Ill-Ill in Figure 1,and Figure4 is a section through part of the surface of a rotarydiscofthetankwashershowing howthespray distribution pattern ofthe latter is produced.

Referring to the drawings, the tankwasher consists of a tube 1 whose upper end is connected to external piping by butt welding. Towards its lower end, the tube 1 has a shaft 5 located in it by an 'R'-shaped resilient clip 2. The shaft is further located centrally in thetube 1 by a water guide 3 which has the additional function of directing the flow of liquid in the required mannerthrough the apparatus. This water guide 3 has a square section holethrough its centre in which is engaged a similar section ontheoutsideoftheshaft5.

Freely rotatable on this shaft 5 is a disc 4whose shape is designed to distribute the liquid overall the internal surfaces of the surrounding tankto be cleaned.

The water guide 3 has a series of helical grooves along its external surface which grooves are cut generally along the axis of the tube 1. These grooves are twisted helically with an angle which is typically 15 .

Figure 4shows a partial section through one of the curved surfaces of the disc 4. If water or other aqueous liquid is directed along the curved surface ofthis disc 4, then itwill leave the edge at a tangentto that surface as shown in Figure 4. As this curve is progressively cut away, the tangent to this edge changes and the curve is designed so that there is a progressive change of this water flow in even increments as the curve changes in annular increments aboutthe centre line.

There are two ofthese curved surfaces above and two below the central body ofthis disc 4. With two such surfaces on each side of the disc 4, the reaction ofthe liquid moving over the surface of the disc its even and balanced and the disc will therefore rotate more uniformly.

Two of the curved surfaces on the top ofthe disc 4 distribute liquid inthetop halfofthetankto be cleaned whilst the two curved surfaces on its bottom distribute the liquid in the lower half ofthe tank.

The liquid which enters the tube 1 in a direction 8 leaves the water guide 3 and is directed onto the curved surfaces of the disc4. Because of the helical grooves in the water guide, the liquid is rotating and this imparts a twist to the disc 4two rotate it at constant speed. Half of the liquid reaching the disc 4 is distributed to the top of the disc to clean the top half of thetank,the rest passes centrally through openings 9 in the body of the disc and is directed by the lower cu rved surfacesto the lower half ofthe tank being cleaned.

The downward fiow ofthe liquid creates an axial thrust on the disc4. In the lower part of this disc4 is a small chamberthat is closed by a head atthe lower end ofthe shaft 5. The disc4 isableto move a small amount on the shaft 5 in an axial direction. Machined into the outside of the shaft 5 are small grooves 7 which convey a small part of the total flow into this chamber 6 in the bottom ofthe disc4. The chamber 6 is )thereby pressurized and lifts slightly to allow some liquid to escape. The lifting of the disc 4 allows just sufficient liquid to escape so thatthe pressure in the chamber 6, and the resultant upward thrust, will balance the downward force due to the liquid impingiing on the disc 4. The result is that the disc4 rotates freely on this 'pad' ofliquid.

Since cleaning operations can be done at high temperatures, even using steam, it is important that the materials ofthe tankwasher should be able to )withstand such treatment.

The drawings originally filed were informal and the print here reproduced is taken from a later filed formal copy.

The claims were filed later than the filing date within the period prescribed by Rule 25(1) of the Patents Rules 1982.

The tankwasherwill frequently be dismantled and needsto berobustenoughtoallowthisto happen.

The disc 4 may be formed from a plastics material, such as nylon or polypropylene, the remainder of the tankwasher being constructed from a suitable grade of high quality stainless steel.

Todismantletheunit,the'R'-shaped resilient clip 2 is withdrawn and all the items fall away from the tube 1. Although the tankwasher is described and ill us- trated as having its tube 1 vertically disposed, this is not essential and it may be horizontally or obliquely disposed where more convenient.

Claims (8)

1. Atankwashercomprising atubearrangedfor connection to a source of washing/rinsing liquid, a shaft mounted in said tube and having an enlarged head at an end thereof which protrudes from the tube, said mounting being accomplished by a pin orthe like that extends releasablythrough aligned openings in the shaft and the surrounding tube, a liquid guide positioned between the shaft and the surrounding tube and arranged to cause liquid passing therethrough from said source to issue therefrom in directions inclined to the longitudinal axes of the shaft and tube, a liquid distribution disc rotatably mounted around said shaft adjacentthe enlarged head thereof for rotation by liquid issuing from the liquid guide, and said disc being shaped to distribute liquid therefrom in a generally fan-shaped pattern at each side of its plane of rotation, and also comprising means substantially to counterbalancethefluid pressure exerted by said source upon the disc, said counterbalance means exhibiting a chamberformed between the disc and the shaft head and a passage connecting said chamberto said source, the disc being axially displaceable along the shaftto a limited extent between the shaft head and the liquid guide.

2. Atankwasher according to claim 1 wherein said pin orthe like constitutes the only connection of said shaftto said tube whereby, upon removing said pin or the like from its operative position, the shaft, the liquid guide and the disc are freely removable from the tube and from each other.

3. Atankwasheraccording to claim 1 or2,wherein said disc comprises two curved surfaces at each oppositesideofits plane of rotation, said curved surfaces being progressively cut away to produce, during use, the generally fan-shaped patterns of liquid distribution at each side of said plane of rotation, apertures being formed in the disco conduct liquid to be distributed from the side thereof facing thetubeto the side thereof remote from said tube.

4. Atankwasher according to any preceding claim, wherein the liquid guide non-rotatably surrounds said shaft, internally of said tube, and has a series of helical grooves along its external surface which grooves are wound generally around the longitudinal axis of said tube.

5. Atankwasher according to claim 4, wherein the angle of helical twist of said grooves relative to the longitudinal axis of the tube has a magnitude of substantially 15

6. Atankwasher according to any preceding claim, wherein the passage connecting said chamber two said source of liquid is formed around said shaft internally ofthe liquid guide and ofthe rotatable disc.

7. Atankwasheraccording to claim 2 orto any one of claims 3 to 6when read as appendantto claim 2, wherein said pin orthe like is a resilient pin of substantially R-shaped configuration.

8. Atankwasher substantially as hereinbefore described with reference to the accompanying drawings.