AU605801B2 - Hydro-cyclone and hydro-cyclone parts, respectively, as well as a method for the production thereof - Google Patents

Description

COMMONWEALTH OF AUSTRA^ 0 r" Q j 1 PATENTS ACT 1952-69 COMVPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Pr omplete Specification Lodged: Accepted: Published: r'ority This dcilmen corains ameindmen ts mace ull Si:clionr 49 and s correct 7 yj rmnting.

Related Art: Name of Applicant: Aadress of Applicant: Actual Inventor: Address for Service: AKW APPARATE UND VERFAHREN GMBH GEORG SCHIFFER STR. 70, 8452 HIRSCHAU, FEDERAL REPUBLIC OF GERMANY FRIEDRICH DONHAUSER EDWD. WATERS SONS, 50 QUEEN STREET, MELBOURNE, AUSTRALIA, 3000.

Complete Specification for the invention entitled: HYDRO-CYCLONE AND HYDRO-CYCLONE PARTS, RESPECTIVELY, AS WELL AS A METHOD FOR THE PRODUCTION THEREOF The following statement is a full description of this invention, including the best method of pel forming it known to mS -2 HYDRO-CYCLONE AND HYDRO-CYCLONE PARTS, RESPECTIVELY, AS WELL AS A METHOD FOR THE PRODUCTION THEREOF iThe invention relates to a hydro-cyclone and H hydro-cyclone parts.

In known hydro-cyclones an outer steel casing is v provided with an inner layer of a relatively soft Spolyurethene. This is disadvantageous in several respects.

The production of such a steel casing is quite expensive and the steel casing is very heavy so that the overall mass of the hydro-cyclone increases accordingly. This mass increases the difficulty of installation and repairs during which the hydro-cyclone or its parts must be replaced. A heavy hydro-cyclone requires more stable and stronger foundations and higher transport costs are incurred when 15 transportation is necessary.

S'If the inner layer has worn away after a long Speriod of operation, then the outer steel layer or casing

S

t S will be worn down very quickly by the constituents of the suspensions processed in the hydro-cyclone, because steel has a relatively low wear strength in respect of the resultant abrasion.

According to this invention, there ic pro!G idcd ji hydro-cyclone comprising a hard, supporting outer laye-/and i a relatively softer, wear-resistant inner layer of polyurethane, characterised in that the outer 1 er comprises a relatively hard polyurethane. A a result the production costs of the outer layer are rduced considerably. At the same time its m a-s, compared to a S prior art hydro-cyclone of the sam outside dimensions, is reduced considerably. If, afte a period of operation, the inner layer has been abrade away by the suspension, at one or more points, then the uter layer of relatively hard polyurethane, which h-s a considerably higher wear strength in this respect tI n steel, is available to increase the service life o such a hydro-cyclone. Surprisingly this improvement n functioning is obtained with a reduction of producti n costs, whereas, as a rule, functional improvements are associated with a.-ninrease in production -ca S-fs 1_ I 2a By way of contrast the object of the present invention is to improve on a hydrocyclone, or hydrocyclone parts to the effect that the support and abrasion resistance of such a hydrocyclone is increased, whereby its production costs should be minimised and whereby also each desired combining of the outer and inner layer is provided for.

The above problem can be alleviated where the outer layer consists of relatively hard polyurethane and the inner layer consists of a contrastingly softer, more wear-resistant polyurethane and where the outer layer "e 1 and inner layer f-r-m- a moulded cm:iua \at their common aO otransition or contact surfaces. An outer layer of relatively hard polyurethane has essentially better o 15 support properties than an outer layer of a 0 oo 0 0 g state-of-the-art synthetic material. Such polyurethanes o°o, are so hard that they do not even deform under the 0 00 internal pressure of the hydrocyclone. The disadvantages of outer layers made of steel according to the further explained state of the art are also avoided.

-oo The abrasion-resistant inner polyurethane layer is a essentially more resistant than the previously known O° a synthetic inner layers. If the inner layer of a oo o hydrocylone according t- the present invention is worn a 25 out or abraded in any place by the suspension after a corresponding time of operation, the outer layer of Qa oa relatively hard poklyurethane provided by the invention o has, compared to the suspension, an essentially greater wear-resistance than in the case of known hydrocyclones.

LI J 2b This prolongs the durability of the hydrocyclone accordingly.

I With this aspect of the invention the surprising effect is achieved, where the function is improved and the production costs are reduced, whereas, as a rule functional improvements of an object can only be gained with a corresponding increase in production costs. At the same time, its mass, compared to prior art hydrocyclones is consderably reduced after a period of 0 operation, the inner layer has been abraded away by the suspension, at one or more points, then the outer layer of relatively hard polyurethane, which has a considerably higher wear strength in this respect than steel, is available to increase the service life of such a hydro-cyclone. The a.zulpz -pr4provided in accordance with the present invention, between outer layer and inner layer, brings about a compound of both layers during the casting process. Such a compound causes an internal adhesion between inner and outer layer, which is not shown by the known state of the art.

j~l 0 Hereby greater stability of the hydrocyclone or i hydrocylcone part results and in such cases where part i 'I 0 of the inner layer was already worn out there is Snevertheless still a sufficient iold by the remaining S part of the inner layer on the outer layer.

So0 oo An alternative solution to the abovementioned exercise o 5 is also seen where the outer consists of a relatively 0oooc hard polyurethane and the inner layer consists of a contrastingly softer, more wear-resistant polyurethane 2c and where a silicon separating layer is provided between outer layer and inner layer. The advantages already explained above are now achieved. A silicon separating layer is now provided between outer and inner layer in place of the rmez'i tl-3d comeu This makes possible the removal of this silicon separating layer from the outer layer in relatively simple fashion, for example by striking or tapping with a hammer, following complete or partial wearing out of the inner layer. Accordingly a new manufactured inner layer can be inserted in the existing outer layer.

0o o o A preferred embodiment of the present invention is where o oo 0i0 Taeanw is provided between the outer layer 0 oo and the inner layer of a hydrocyclone consisting of 0 oo 15 several parts, adjacent to a top part containing the 000000 suspension feed and overflow, while in the remaining 0 0 o°oo area of the hydrocyclone, in which separation of 0 00 fractions and settling of heavy or coarse fractions occurs, a silicon separating layer is provided between the outer layer and the inner layer. The remaining area ooooo of the hydrocyclone may further consist of an 0o- intermediate part and a lower part. The firm cohesion, 0 0 00 o which increases stability, on the top part oo o correspondingly stressed by the suspension feed is 0o 25 reduced by the moulded compound, while the lower area (lower part, or intermediate part and lower part) o oa especially exposed to wear enables a worn inner layer to oo o 0 a be quickly and easily exchanged.

0 0 0 0 o o ;-1.~Pf~A U3 in a preferred embodiment of the invention the outer layer and the inner layer are joined together at their common transition surfaces by cast bonding. such cast bonding of the two layers ensures intimate adhesion between the inner and outer layers which does not exist in the prior art. This results in greater stability of the hydro-cyclone and hydro-cyclone parts and in those cases where part of the inner layer has been worn away, adequate adhesion of the remaining part of the inner layer to the outer layer is maintained.

if it is preferred, a silicone coating may be provided between the inner and outer layers which makes it possible, after complete or partial wearing away of the inner layer, to loosen the inner from the outer layer in a simple manner, e.g. by -tapping it or hitting it with a hammer. Subsequently a new, pre-fabricated inner layer can be put into the existing outer layer.

O0 The cast bonding can be limited to the top part of the cyclone, which is acted upon by the inflowing whereas the lower parts, which are particularly subject to wear, could have a quick and easily replaceable 00 inner layer.

The invention extends to parts for hydro-cyclones 0r and to a method for the production of such hydro-cyclones a 0 25 and hydro-cyclone parts. in this method the outer, o 0 supporting layer is produced whereafter the material of the CIO inner, softer layer is cast into the outer layer and allowed 0 0 00 to harden. This has the advantage that the material of the 0o inner layer need not be heat-treated twice. With many polyurethanes repreated heat-trearnent could cause a reduction of the wear strength. With this variant of the invention, slightly higher moulding costs for casting the outer layer will have to be accepted.

Alternatively, a method could be adopted of casting the outer layer around the inner layer, reducing the mould costs. The polyether-polyurethane indicated for this purpose can withstand the second heat treatment in the form of curing without loss of wear strength. Such a I4 polyether-polyurethane is made, for example, by DUPONT and is sold by UNIROYAL under the trademark "L 42".

An embodiment of the invention is illustrated in the drawings in which Fig. 1 is a longitudinal section through a hydro-cyclone consisting of bottom-, middle- and top parts; and Fig. 2 is a section along a line II-II in Fig. 1.

The hydro-cyclone illustrated consists, in principle, of three parts, namely a bottom part 1, a middle part 2, and a top part 3. The bottom part 1 forms the outlet for the heavy, or coarse fraction. The middle part 2 0 oca forms an area 5 where, essentially, the fine or light 0 0 ooo fraction of the suspension is separated from the coarse or 0 15 heavy fraction by the cyclone effect. The top part 3 Soo° contains the suspension inlet 6 and the overflow 10 for the °0 fine or lighter fraction.

o°O The parts, insofar as they have a supporting C Ce function, consist of an outer layer indicated throughout by the reference numeral 7, which is made of a relatively hard polyurethane so that it can assume a supporting function, and a relatively softer, highly wear-resistant inner layer 8 of a correspondingly softer polyurethane. In a preferred embodiment of the invention the Shore-hardness of the outer layers 7 amounts to about 95 to 105 Shore, whereas the Shore hardness of the inner layers is preferably 75 to 85 Shore A.

The layers 7, 8 are preferably joined and held together at their contact surface 9 by cast bonding.

However, it is also possible to proceed such that after casting one of these two layers, a thin silicone coating 11 is applied, preferably by spraying, onto the area which will come in contact with the counter-surface of the second layer. In this case, after the inner layer has worn, it can easily be separated from the outer layer and be replaced by a new inner layer. In the present embodiment it is recommended that in the top part 3 the outer and inner layers are firmly joined together by cast bonding, but that in the middle part 2 and bottom part 1 a silicone coating is provided between the outer and inner layers, since the greatest wear is to be expected in these regions. In the drawing this silicone coating is indicated only by the reference numeral 11 and by the associated separating line between the inner and outer layers of the hydro-cyclone parts 2 and 1.

Two manufacturing methods are proposed:- in the first, the outer layer 7 is produced whereafter the inner layer 8 is cast into the shell so provided; or, in the Ssecond method the inner layer is cast first, whereafter, following suitable heat-treatment of the inner layer, the outer layer is cast around it. In the latter case a polyurethane must be chosen for the inner layer which can withstand the double heat-treatment necessary for complete curing of the entire assembly without loss of wear strength.

Sco 15 STo this end a polyether-polyurethane with a Shore hardness of about 80 Shore A should be used.

In the foregoing the invention has been explained with reference to the exemplified embodiment of a hydro-cyclone which consists of several parts. As already mentioned, the invention would also find application in a hydro-cyclone.designed in this manner, but consisting of .ohy<_ -cyc-. n _ia.am_.N c ncist t aoomvndod i- 0 3

Claims (6)

1. A hydrocyclone, or hydrocyclone parts, consisting only of two layers, namely a hard, synthetic supporting outer layer and a softer, synthetic inner layer, wherein the supporting outer layer consists of a relatively hard polyurethane and the inner layer consists of a softer, more wear-resistant polyurethane, and wherein the supporting outer layer and the wear-resistant inner layer are cast bonded at their transition or contact surfaces.

2. A hydrocyclone as claimed in claim 1, characterized in that adjacent a top part containing a suspension feed and overflow, cast bonding is provideC between the supporting outer layer and the wear-resistant inner layer, while in the remaining area of the hydrocyclone, in which separation of fractions and settling of heavy or coarse fractions occurs, a silicon separating layer is provided between the supporting outer layer and the wear-resistant inner layer. cor oo: 3. A hydrocyclone as claimed in Claim 2, wherein the Soo remaining area of the hydrocyclone consists of an intermediate part and a lower part.

4. A hydrocyclone as claimed in any one of Claims 1 to 3, wherein Shore hardness of the supporting outer layer measures from 95 to 85 Shore A. A hydrocyclone as claimed in any one of Claims 1 to 4, wherein Shore hardness of the inner layer measures from to 85 Shore A. 7

6. A, method for manufacturing a hy'droc.yclon.e as claimed in any one of Claims 1 to 5, wherein the outer layer is produced first and then material for inner layer is cast into the outer layer and cure hardened.

7. A method for manufacturing a hydrocyclone as claimed in any one of Claims 1 to 5, wherein, the inner layer is moulded from a polyether-polyurethane with a Shore hardness of substantially 80 Shore A, and then followed by heating (annealing) of the inner layer and following curing of the inner layer, casting the outer layer from harder polyurethane around the inner layer, S8,. A hydrocyclone as claimed in claim 1 or 2, oo substantially as herein described with reference to the 0 C 0o O accompanying drawings, 0" 00

9. A method as claimed in claim 6 or 7, substantially as herein described with reference to the accompanying S t drawings. i DATED this 16th day of October 1990. 1 *AKW APPARATE UND 'VERFAHREN GMBH 'I WATERMARK PATENT j TRADEMARK ATTORNEYS 290 BURWOOD ROAD, HAWTHORN, VICTORIA,J AUSTRALIA,. LJD:RCTS:BB(8.42)