AU640108B2 - Treatment of skins and hides - Google Patents

Description

OPI DATE 12/01/90 APPLN. ID 37734 89 PC4' AOJP DATE 15/02/90 PCT NUMBER PCT/AU89/00257 INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 4 C14C 15/00, C14B 1/26 C14C 1/00, 1/06, 3/30 D06P 3/32, 7/00, 5/20 (11) International Publication Number: WO 89/12698 (43) International Publication Date: 28 December 1989 (28.12.89) (21) international Application Number: (22) International Filing Date: Priority data: PI 8772 15 June 1 PCT/AU89/00257 15 June 1989 (15.06.89) 988 (15.06.88) (71) Applicants (for all designated States except US): TANNING TECHNOLOGIES PTY LTD [AU/AU]; 6 Montrose Place, Beaumont, S.A. 5066 AUSTRALIAN MEAT LIVE-STOCK RESEARCH DEVELOP- MENT CORPORATION [AU/AU]; Cnr Elizabeth Bathurst Streets, Sydney, NSW 2000 (AU).

(72) Inventor; and Inventor/Applicant (for US only) ANDERSON, Colin, Charles [AU/AU]; 6 Montrose Place, Beaumont, S.A.

5066 (AU).

(74) Agent: GRANT, Patent Attorney Services, 26 Ellingworth Parade, Box Hill, VIC 3128 (AU).

(81) Designated States: AT, AT (European patent), AU, BB, BE (European patent), BF (OAPI patent), BG, BJ (OAPI patent), BR, CF (OAPI patent), CG (OAPI patent), CH, CH (European patent), CM (OAPI patent), DE, DE (European patent), DK, F1, FR (European patent), GA (OAPI patent), GB, GB (European patent), HU, IT (European patent), JP, KP, KR, LK, LU, LU (European patent), MC, MG, ML (OAPI patent), MR (OAPI patent).

MW, NL, NL (European patent), NO, RO, SD, SE, SE (European patent), SN (OAPI patent), SU, TD (OAPI patent), TG (OAPI patent), US.

Published With international search report.

640108 (54) Title: TREATMENT OF SKINS AND HIDES (57) Abstract A process and apparatus for treating a hide (10) with a fluid. The hide (10) is stretched longitudinally and/or laterally. In one embodiment the hide (10) passes from upstream rollers (14) to downstream rollers (15) rotating at a higher speed to stretch the hide (10) longitudinally. Left hand rollers (16, 17) and right hand rollers (18, 19) can be angled to the line of travel (20) so that the hide is stretched laterally. In a second embodiment the hide (10) is clamped between upper and lower edges (45u, 451 and 46u, 461) and the lines of clamping are moved apart, longitudinally by separating sets (40, 41) of clamping means and/or laterally by arranging the lines of clamping at an acute angle a to the centre line (20) and increasing that angle towards 90°. Liquid is sprayed onto the underside of the hide (10) while stretched through manifold (31) having nozzles (32).

PCr/AU89/00257 WO 89/12698 TRhETMENVI OF SKINS AND HIDES This invention relates to the use of treatment fluids in the treatment of skins and hides, including both green and re-hydrated skins and hides, which for convenience will be called "hides"f throughout the specification.

The presently used processes for treating animal hides so as to produce leather or pelts or to retrieve wool in the fell imngering process involve treating the hides with chemicals in a fluid, particularly a liquid. The chemicals used may include depilitants for de-wooling or de-hairing, various acids and other fluids for tanning or dyeing puirposes. The conventional method of treating hides is to immerse the hides in a vessel containing a volume of liquid with the active chemiicals in the liquid. The hides are left inmersed in the liquid in the vessel for substantial periods of time, such as up to thirty hours in tanning of hides. The liquids in the vessel may be agitated to accelerate the penetration of the liquids into the hides.

The batch nature of the processing together with the treatment tim-es needed make the treatment of hides an uneconomic proposition for most abattoirs where the green hides are recovered from freshly slaughtered animals. Frequently the green hides are simply salted and/or dried and exported or conveyed to remote tanning and fell mo~ngering works with low monetar-y return to the albattoirs.

The batch process results in large volumes of the treatment liquids being inefficiently used and the spent liquids present a substantial pollution problem if they are not extensively processed before discharge.

It is an object of the present invention to provide a process and apparatus for treating hides which enables very effective and relatively rapid treatment of hides with treatment fluids.

it is a further and preferred object of the present invention to provide a process and apparatus for treatment of hides with treatment fluids which can be economically used to process relatively small numbers of hides, e.g. at or in the vicinity of relatively small abattoirs.

2 It is a further preferred object of the present invention to provide a process and apparatus for treatment of hides with treatment fluids and which enables the substantially continuous processing of individual hides.

According to the present invention there is provided a process for treating a hide with a treatment fluid, the hide when spread out to lie in a plane having a longitudinal dimension and a transverse dimension and a centre line extending along the length thereof in the longitudinal dimension, the method comprising the steps of: stretching the hide so as to simultaneously extend the hide in both the longitudinal dimension and the transverse dimension and thereby render the hide in a stretched condition, the hide in the stretched condition being extended in both the longitudinal and transverse dimensions to an extent sufficient to open the hide structure and promote penetration of the treatment fluid into the hide as a result of the opening of the hide structure, the step of stretching the hide comprising engaging the hide at a plurality of engagement points including both multiple engagement points spaced apart and located on opposite transverse sides of the centre line and also multiple engagement points which are spaced apart in the longitudinal dimension, and applying stretching forces to the hide at the engagement points, the stretching forces including stretching forces applied in both the longitudinal dimension and the transverse dimension so as to thereby simultaneously stretch the hide in both those dimensions and thereby open the hide structure, and applying the treatment fluid to the hide at least where the hide is in the stretched condition in both the longitudinal dimension and the transverse dimension so that the fluid penetrates into the opened hide structure.

30 The multiple engagement points may be dispersed throughout substantially the entire surface area of the hide so that the stretching of the hide to open the hide structure occurs throughout the surface area of the hide.

The step of applying the treatment fluid is preferably carried out simultaneously with and during the step of stretching the hide in the longitudinal and transverse dimensions.

3 The step of stretching the hide preferably comprises stretching the hide in both of the dimensions by greater than five percent, and preferably greater than ten percent, of the initial length of the hide in the dimensions before the stretching.

In one possible process, the step of stretching the portion of hide comprises feeding the hide from an upstream pair of driven nip rollers to a downstream pair of driven nip rollers spaced from the upstream pair and rotating at a greater rotational speed than the upstream pair of driven nip rollers so as to stretch the hide in the general direction of advance of the hide, the step of applying the treatment fluid taking place between the upstream and downstream pairs of rollers. The downstream nair of driven rollers may comprise left and right hand pairs of co-operating rollers, both the left and right hand pairs of rollers being angled at an acute angle to the general line of advance of the hide so that the hide is stretched in a direction transverse to the general direction of advance as it passes through the angled pairs of rollers.

In an alternative possible process, the step of stretching the hide comprises clamping the hide along clamping lines arranged at an acute angle to the general centre line and subsequently moving each of the clamping lines towards respective lines at ninety degrees to the centre line so as to thereby stretch the hide in a direction transverse to the centre line.

The step of applying treatment fluid may comprise directing a stream of fluid under pressure into contact with the hide. The fluid preferably comprises a liquid and the step of directing the stream comprises directing the liquid from beneath the hide so that excess liquid can fall from and be collected beneath the hide.

The step of applying the treatment liquid in alternative 30 possible embodiment comprises contacting the surface of the hide with a liquid bearing applicator. For example, the liquid bearing applicator may comprise a porous compressible applicator bearing the liquid, the applicator being compressed under pressure against the hide surface so that the liquid held by the applicator is applied to the hide surface, 4 The present invention also provides an apparatus for treating a hide with a treatment fluid, the hide when spread out to lie in a plane having a longitudinal dimension and a transverse dimension and a centre line extending along the length thereof in the longitudinal dimension, the apparatus comprising: stretching means for stretching the hide so as to simultaneously extend the hide in both the longitudinal dimension and the transverse dimension and thereby render the hide in a stretched condition, the hide in the stretched condition being extended in both the longitudinal and transverse dimensions to an extent sufficient to open the hide structure and promote penetration of the treatment fluid into the hide as a result of the ppening of the hide structure, the stretching means comprising engagement means to engage the hide at a plurality of engagement points including multiple engagement points spaced apart and located on opposite transverse sides of the centre line and multiple engagement points which are spaced apart in the longitudinal dimension, the stretching means further including means for applying stretching forces to the hide at the engagement points, the stretching forces including stretching forces applied in both the longitudinal dimension and the transverse dimension so as to thereby simultaneously stretch the hide in both those dimensions and thereby open the hide structure, and fluid applying means operative to apply the treatment fluid to the hide at least where the hide is in the stretched condition in both the longitudinal dimension and the transverse dimension so that the fluid penetrates into the opened hide structure.

The multiple engagement points are preferably dispersed throughout substantially the entire surface area of the hide so that the stretching of the hide to open the hide structure occurs throughout the surface area of the hide.

The fluid applying means is preferably operative to apply the treatment fluid to the hide simultaneously with and during the process of stretching of the hide in the longitudinal and transverse dimensions by the stretching means.

The stretching means may comprise an upstream set of cooperating nip rollers between which the hide is passed, and a downstream set of cooperating nip rollers between which the hide is passed, the upstream and downstream sets of nip rollers being separated in the longitudinal dimension of the hide by a distance such that the hide is simultaneously in both sets of nip rollers, the downstream set of nip rollers being driven at a greater speed than 'the upstream set of nip rollers so that when the hide is being passed therethrough, the hide is stretched in the longitudinal dimension as a result of the speed difference, the downstream set of nip rollers comprising a left side pair of downstream nip rollers and a right side pair of downstream nip rollers, the axes of the left and right side pairs of downstream nip rollers being non-colinear and at least one of the pairs of downstream nip rollers having its axis angled at an acute angle to the direction of a line from the downstream set of nip rollers to the upstream set of nip rollers so as to be operative to stretch the hide in the transverse dimension as it passes to and through the downstream nip rollers, the fluid applying means being operative to apply the treatment fluid to the hide in the space between the upstream and downstream sets of nip rollers while passing therethrough and where the hide is being stretched.

The left side and right side pairs of downstream nip rollers may be each arranged at an angle of between 70' and 870 to the longitudinal dimension of the hide.

In an alternative embodiment of the apparatus, the engagement means comprises at least two clamping means for clamping the hide at multiple points including points spaced apart in the longitudinal dimension of the hide and points spaced apart in the transverse dimension of the hide, the stretching means further including moving means for moving the clamping means relatively apart in both the longitudinal dimension and the transverse dimension, whereby the movement of the clamping means increases the separation of the 30 clamping points which are spaced apart in the longitudinal dimension thereby causing stretching of the hide in the longitudinal dimension, and whereby the movement of the clamping means also increases the separation of the clamping points which are spaced apart in the transverse dimension thereby causing stretching the hide in the transverse dimension. Some of the multiple points are preferably nearer to the centre line than others and the points nearer to the .oj'u q' 4b centre line are relatively moved apart by the moving means to a lesser degree than the clamping points further from the centre line.

The multiple clamping points on each side of the centre line may lie in a respective general line extending away from the centre line at an acute angle to the general centre line, the clamping means being movable by the moving means so as to increase the angle to the centre line towards 90' and thereby stretch the hide in the transverse dimension between the clamping points on opposite sides of the centre line. The clamping means may comprise pairs of respective upper and lower clamping edges co-operable to clamp and hold the hide between the respective edges, each of adjacent pairs of respective edges on the opposite sides of the general centre line defining a shallow V-shape, the moving means being operable to move the clamping edges with a hinging movement so as to cause the shallow V-shape to approach a straight line. The clamping means may comprise a plurality of adjacent spaced generally parallel sets of co-operating upper and lower clamping edges, the fluid applying means being located between adjacent sets of clamping edges.

The apparatus may further including conveying means for conveying the hide to a stretching and treatment station where the stretching means and the fluid applying means are provided, the conveying means being further operative to convey the hide after treatment at the stretching and treatment station away from that station. For example, the conveying means may comprise a conveyor composed of a plurality of strands extending in the longitudinal.

dimension on which the hide is carried, the strands being movable apart laterally during operation of the stretching means to effect stretching of the hide in the transverse dimension. The clamping means may comprise a lower clamping edge engageable with an 30 undersurface of the hide, the clamping edge having a plurality of notches therein, the strands of the conveyor passing through the notches so as to be movable apart as the angle of the clamping edge to the general longitudinal line of the strands changes from an acute angle towards an angle of 90

I,

WO 89/12698 PC/AU89/00257 of- the stretehing eans to off ot lateral stretohing of the hide. In this diment, and where the clamping means comprises a lower clamping edge e le with an undersurface of the hide, the clamping edge preferably a plurality of notches therein, the strands of the conveyor passing thr the notches so as to be movable apart as the angle of the clamping to the general longitudinal line of the strands changes from an acute angle ds an angle of Possible and preferred features of the present invention will now be described with particular reference to the accompanying drawings. However it is to be understood that the features illustrated in and described with reference to the drawings are not to be construed as limiting on the scope of the invention. In the drawings: Fig. 1 shows a perspective view of the principal components of an apparatus for treating hides according to a first preferred embodiment of the present invention, Fig. 2 is a simplified plan view of the apparatus of Fig. 1, Fig. 3 is a perspective view of a second apparatus for treatment of hides according to a further preferred embodiment of the present invention, and Fig. 4 is a simplified plan view of a section of the apparatus shown in Fig. 3.

Referring to Fig. 1, there is illustrated an apparatus for treating a hide 10 with a fluid. The apparatus comprises stretching means 11 for stretching a portion of the hide 10 so as to extend the hide and at least one dimension. Fluid applying means 30 is operative to apply a treatment fluid to the hide 10 when the hide is in the stretched condition so that the fluid penetrates into the hide. The stretching of the hide 10 occurs to an extent sufficient to open the hide structure. This promotes and allows rapid penetration of the fluid into the hide 10 as a result of the opening of the hide structure. The stretching comprises stretching by at least 3% in at least one dimension, preferably by at least 5% and most preferably by at least 105.. It is believed that stretching less that 25% and most preferably less than 20% is desirable.

The -apparatus includes an upstream set of locating and WO 89/12698 P1/~8/Q5 PCT/AU89/0025"i 6 transferring means 12 and a downstream set of locating~ of transferring means 13 which are operative to locate the hide 10 and to transfer the hide 10 past the locating means 12, 13. The upstream and downstream sets 12, 13 are spaced apart and the downstream set 13 operative to transfer the hide 10 at a greater speed than the upstream set 12 so that the hide 10 is stretched between the upstream and downstream sets. In the emnbodiment of Figs. 1 and 2 the upstream and downstream sets 12, 13 corrprise co-operating sets of nip rollers 14, 15 respectively between which the hide 10 is passed. The downstream nip rollers 15 are driven at a greater rotational speed than the upstream nip rollers 14. The fluid applying means 30 is located between the upstream and downstream rollers 14, 15. The drive means 33, 34 for the rollers is illustrated schematically in Fig. 2.

The downstream set of rollers 15 comprises a left side pair of nip rollers 16, 17 and a right side pair of nip rollers, 18, 19. The axes of the left and right hand pairs, 1.6, 17 and 18, 19 are non-colinear as best seen in Fig. 2. Both pairs are angled at an acute angle to the general line of advancement 20 of the hide 10 in the upstream direction so as to be effective as to stretch the hide laterally as it passes through the angled rollers. This lateral stretching results from the fact that the left side pair of rollers 16, 17 are tending to draw the hide 10 therethrough in the direction of arrow A while the right side rollers 18, 19 are tending to draw the hide 10 through in the direction of arrow B.

In Figs. 1 and 2 both the upstream set of rollers 14 and the downstream set of rollers 15 comprise left and right side pairs of rollers angled to the line of advancemient 20 of the hide 10. The upstream rollers 14 ccxrprise a left side pair of rollers 21, 22 and a right side pair of rollers 23, 24.

The mounting of the rollers and the driving of the rollers may be achieved in any convenient manner. In Fig. 1 there is schemtically illustrated a mounting arrangement for the upper rollers 16, 18 of the downstream rollers 15. This mounting arrangement for roller 18 comprises mtounting bar 24 to which bearings at the ends of the roller 18 are mocunted, the bar 24 in turn being supprted on arms 26 which are pivotally m-ounted at their ends remrote WO 89/12698PI/U8025 PCT/AU89/00257 7 from thEp bar 24 to a frame 27 cf the apparatus. The upper rollers 16, 16 may be capi!,le of being raised and also the pressure being applied between the co-operating upper and lower rollers my be selectively variable by means of the air ram 29, or other convenient movmnt means. The upper rollers 21, 23 of the upstream set of rollers 14 mry be similarly mo~unted although for clarity this mo~unting is not shown in Fig. 1. The lower rollers 17, 19, 22, 24 my be mounted directly to other portions (not shown) of the apparatus frame 27.

Lower rollers 19, 24 are shown as being driven by electric motors 33, 34 in any convenient manner. The relative speeds of the motors 33, 34 are selectively variable so that the speed differential between the upstream and downstream rollers can be controlled as desired. For example, the downstream rollers mry be driven at rotational speed about 25% higher than the upstream rollers so that, with some degree of slipping of the hide as it passes through the rollers, an elongation of the hide in the general line of advancement greater than 10% and less than 25% is produced. The spacing between the upstream and downstream sets of rollers 14, 15 in the direction 20 may be any convenient distance such as in the order of The width of the roller assembly may be, say, 200cm. The angle that the rollers define with the line of advance 20 of the hide mr: be- greater than 60' and less than 90' and preferably between and 85', e.g. about 60' has been found effective. The angle may be selectively variable to enable operator control of the degree of lateral stretching of the hide 10. The other parameter which will affect the degree of lateral stretching is the pressure applied between the upper and lower rollers since this will control the extent of slipping of the hide. Pressures variable between 200 and 600 kPa may be used. The speed differential between the upstream and downstream sets of rollers affects the degree of longitudinal stretching of the hide.

In the space between the upstream rollers 14 and downstream rollers 15 there is located the fluid applying means 30 which applies fluid in the form of a stream under pressure. The fluid corprises a liquid and the stream is directed into contact with the hide 10 from beneath the hide so that excess liquid can fall from and be collected WO 89/12698 PTA8/05 PCT/AU89/00257 8 beneath the hide 10. The liquid applying means 30 is shown as a manifold 31 having a plurality of nozzles 32 for directing sprays or jets of liquids upwardly, the manifold 31 being supplied from a source of fluid and a pimp (not shown) through supply line 31a. An alternative form of liquid supplying means 30 shown in broken line in Fig. 2 comprises a liquid bearing aplicator 35 which my be in the form of a porous corpressible applicator 35 bearing the treatment liquid. The applicator 35 may be in the form of a roller and may be pressured upwardly against the hide surface so that the liquid* held by the applicator 35 as applied to the hide surface. This can make economical use of the treatnent fluids. Aplication of treatment liquid to all parts of the surface, including both sides of the hide surface, is not believed necessary, since the stretching of the hide and opening of the hide structure makes the hide porous and the liquid will migrate throughout the hide by capillary action in the manner of liquid migrating through blotting paper.

In a second possible embodiment shown in Figs. 3 and 4, the stretching means 11 comprises clamping means 40, 41 for clamping the hide 10 at spaced points and movving means 42 for rmving the clamping means 40, 41 relatively apart to stretch the hide 10. In Fig. 3 the clamping means 40, 41 are separated in the general direction of the centre line 20 of the hide 10 and the moving means 42 separates the clamping means 40, 41 in any convenient manner to cause stretching of the hide 10 in the direction of the centre line 2H The clamping means in Figs. 3 and 4 is also operative to stretch the hide 10 transverse to the centre line 20 and for this purpose comprises means 45, 46 for clam-ping the hide 10 at multiple points on each of two opposite sides of the centre line 20 of the hide 10, the mroving means 42 being operative to mtove the clamping points relatively apart in a direction transverse to the centre line The clamp~ing means 45, 46 comprise upper and lower clamping edges 45u, 451 and 46u, 461 which can be firstly moved relatively towards each other firom the position shown in Fig. 3 to clamp and hold the hide 10 between the edges. The clamping edges clamp the 10 at multiple points on each side of the centre line 20, the lines of clamping extending away from the centre line 20 at an acute angle a to the centre line 20 as best seen in Fig. 4. The mroving WO 89/12698 PCT/AU89/00257 9 means 42 is operable to move the clamnping means 45, 46 to increase the angle a~ towards 900 and thereby stretch the hide 10 in a direction transverse to the centre line 20. In particular, as seen in Fig. 4, the edges 45u, 451 and 46u, 461 on oposite sides of the centre line 20 define a shallow V-shape, the mroving means 42 being operable to mocve the clamp~ing edges with a hinging movmnt in the direction of arrows C and C' to cause the uhal low V-shape to approach the straight line 49. With this arrangmnt, the clamping points nearer to the centre line 20 are relatively mroved apart to a lesser degree than the clamp~ing points further froan the centre line 20 so that the stretching of the hide 10 in the lateral direction can be relatively uniform.

In the emnbodiment of Figs. 3 and 4 the clam~ping means comprises a plurality of adjacent generally parallel sets of co-operating upper and lower clamp~ing edges 45u, 451, 46u, 461, etc. spaced apart in the direction of the centre line 20. The fluid applying means 30 is located between adjacent sets of clamping edges so that the hide is contacted with the treatmrent fluid when the moving means 42 operates to stretch the hide The apparatus in Figs. 3 and 4 also includes conveying means for conveying the hide 10, the conveying mans comrprising a plurality of longitudinally extending strands 51 on which the hide 10 is carried. The strands 51 are mo~vable apart laterally during operation of the stretching means to effect lateral stretching of the hide This is achieved by providing the lower clamping edges 451, 461 with a plurality of notches 52 therein, the strands 51 of the conveyor passing through the notches 52 so as to be mrovable apart as the angle a of the clamping edges 451, 461 to the general longitudinal line of the strands 51 changes fromn an acute angle towards an angle of In use of the apparatus shown in Figs. 3 and 4, the hide 10 on the conveyor 50 can be advanced to the position between the separated upper and lower clamping edges 45u, 451, etc. and the conveyor 50 can then be stopped and the uppr and lower clamping edges 45u, 451, etc.

brought together to clamp the hide. Longitudinally spaced sets 41 of clamping means can be moved apart to the desired degree to stretch the hide 10 longitudinally. At. the same time the left and WO 89/12698 PCV/AU89/00257 right hand sets 45, 46 of clamrping mans can be hinged to increase the acute angle a towards 900 to thereby laterally stretch the hide When the hide is in a stretched condition, the iguid can be sprayed into contact with the undersurface of the hide.

The apparatus in Figs. 3 and 4 ma., be utilised with mz-difications to enable zmre user control of '.he degree and location of stretching. For examtple, in one possible embodiment, clamp~ing edges may be operative to engage only with edge regions of a hide, the clamp~ing edges then being relatively separated to flatten and effect some stretching of the hide at the edges. After this, further clamp~ing edges can be engaged with the hide substantially across the entire width and along the length of the hide, generally as shown in Figs. 3 and 4, and the apparatus operated to stretch across substantially the entire width and along substantially the entire length of the hide.

In the drawings, the fluid applying means 30 has been illustrated as a manifold with nozzles along its length. Greater amounts of liquid may desirably be applied to different parts of the hide. For example, some hides have a greater thickness along the general centre of the back compared to the flanks and therefore a greater volumre of liquid may need to be applied along the general central region of a hide. For this purpose the apparatus may include a plurality of manifolds and associated nozzles, some manifolds being relatively short iin length and located in regions beneath the hide where miore liquid is to be applied. For example in the embodiment of Figs. 3 and 4, in addition to the manifold 31. illustrated, the my be provided one or mtore further manifolds (not shown) of shorter length but symnertrically extending on oposite sides of the centre line 2G so that mrore liquid will be applied to the general central region of the hide 10. Also it is possible that the liquid applying means could be mrovable beneath the hide instead of being in a fixed location as illustrated. For examp~le, particularly in Figs. 3 and 4, a manifold 30 may be miounted on a carriage which can trove in the general direction of the centre line 20 beneath the clamping means 40, 41, etc. so that the hide is stationary and held in a stretched condition while liquid is sprayed along the length of the hide from beneath.

PCT/AU89/00257 WO 89/1268 11 In the preferred embodiments liquid is sprayed onto the undersurface of the hide, but is is possible to spray the upper side or both sides. The hide may be arranged in a generally vertical S plane during stretching and application of liquid so that excess liquid runs off the bottom edge.

It has been found that depilitant liquids can be effectively applied to only the side of the hide having hair or wool, whereas in the past it was not believed possible to apply depilitants from that side of the hide only because the hair or wool would prevent or retard the liquid reaching the follicles. However the spreading opens the spaces between the hair or wool allowing the liquid to be sprayed so as to easily reach the follicles and start reacting quickly. This enables a de-hairing operation to be carried out a short time after application of the liquid and the hide can be scraped to remove the hair or wool while relatively dry ;.ompared to a saturated hide resulting from soaking or application of liquids to the inside of the hide.

Other apparatus for stretching the hide could be used according Sto .the invention. For example, the hide could be stretched by clanping at its edges and the clarmping means moved apart, although this apparatus may not be so adaptable to different sizes of hides as the apparatus illustrated. Another apparatus possibly usable for stretching a could comprise double helical rollers having helical formations of opposite hand on each side of a centre of the rollers so that the skin is stretched laterally by the action of the roller as it passes through, preferably with some restraint on the hide so that there is slipping of the hide and the movement of the helical formations across the hide surface promotes lateral stretching.

The hide treatment time using the present invention can be reduced substantially. The time that the hide is exposed directly to the application of treatment fluid may be less than one minute, but this is variable according 'o the particular conditions, e.g. hide type merino skins are heavily wrinkled and may need longer exposure times for sufficient liquid to be applied), concentration of chemicals being applied, degree of stretching which can affect speed WO 89/12698 PT/AU89/00257 12 of liquid penetration, type of treatment being carried out (de-hairing, tanning, dyeing, etc.). The hide can be stored at a waiting station where the chemical action of the fluids on the hide takes place, e.g. for a time up to two hours. The hide can then be further treated e.g. by removing wool or hair, or washing or neutralising of the chemicals, etc.

The entire treatment of the hide from being a green hide freshly obtained from abattoirs to a de-haired and tanned hide can be in the order of a few hours.

Hides can be processed on a substantially continuous basis. In the embodiment of Figs. 1 and 2, hides can be joined end to end, e.g.

by stapling, to form a continuous elongated "sheet" of hides which can be fed continuously through the rollers. In Figs. 3 and 4, individual hides can be laid on the conveyor and fed to the apparatus one at a time on a continuous basis.

The preferred process and apparatus of the present invention enables efficient use of the treatment chemicals with a potentially significant reduction of the pollution caused by discharged liquids in the known hide treatment processes.

It is to be understood that various alterations, modifications and/or additions may be made to the features of the possible and preferred embodiment(s) of the invention as herein described without departing from the spirit and scope of the invention.

Claims (24)

1. A process for treating a hide with a treatment fluid, the hide when spread out to lie in a plane having a longitudinal dimension and a transverse dimension and a centre line extending along the length thereof in said longitudinal dimension, the method comprising the steps of: stretching the hide so as to simultaneously extend the hide in both the longitudinal dimension and the transverse dimension and thereby render the hide in a stretched condition, the hide in said stretched condition being extended in both the longitudinal and transverse dimensions to an extent sufficient to open the hide structure and promote penetration of said treatment fluid into the hide as a result of the opening of the hide structure the step of stretching the hide comprising engaging the hide at a plurality of engagement points including both multiple engagement points spaced apart and located on opposite transverse sides of said centre line and also multiple engagement points which are spaced apart in the longitudinal dimension, and applying stretching forces to the hide at said engagement points, the stretching forces including stretching forces applied in both the longitudinal dimension and the transverse dimension so as to thereby simultaneously stretch the hide in both those dimensions and thereby open the hide structure, and applying said treatment fluid to the hide at least where the hide is in said stretched condition in both the longitudinal dimension and the transverse dimension so that the fluid penetrates into the opened hide structure.

2. A process as claimed in Claim 1 -wherein said multiple engagement points are dispersed throughout substantially the entire S surface area of the hide so that the stretching of the hide to open the hide structure occurs throughout said surface area of the hide.

3. A process as claimed in Claim 1 or 2 wherein said step of applying said treatment fluid is carried out simultaneously with and Ji. during the step of stretching the hide in the longitudinal and transverse dimensions.

4. A method as claimed in Claim 1, 2 or 3 wherein the step of stretching the hide comprises stretching the hide in both of said dimensions by greater than five percent of the initial length of said S hide in said dimensions before said stretching.

A method as claimed in Claim 4 wherein the step of stretching the hide comprises stretching the hide in both of said dimensions by greater than ten percent of the initial length of said hide in said dimensions before said stretching,

6. A process as claimed in any one of the preceding claims wherein the step of stretching the portion of hide comprises feeding the hide from an upstream pair of driven nip rollers to a downstream pair of driven nip rollers spaced from the upstream pair and rotating at a greater rotational speed than the upstream pair of driven nip rollers so as to stretch the hide in the general direction of advance of the hide, the step uf applying the treatment fluid taking place between the upstream and downstream pairs of rollers.

7. A process as claimed in Claim 6 wherein the downstream pair of driven rollers comprise left and right hand pairs of co-operating rollers, both the left and right hand pairs of rollers being angled at an acute angle to the general line of advance of the hide so that the hide is stretched in a direction transverse to the general direction of advance as it passes through the angled pairs of rollers.

S. A process as claimed in any one of Claims 1 to 5 wherein the step of stretching the hide comprises clamping the hide along clamping lines arranged at an acute angle to the general centre line and subsequently moving each of the clamping lines towards respective lines at ninety degrees to the centre line so as to thereby stretch the hide in a direction transverse to the centre line.

9. A process as claimed in any o:.e of the preceding claims wherein the step of applying treatment fluid comprises directing a stream of fluid under pressure into contact with the hide.

A process as claimed in Claim 9 characterised in that the fluid S 30 comprises a liquid and the step of directing the stream comprises Sdirecting the liquid from beneath the hide so that excess liquid can fall from and be collected beneath the hide. t

11. A process as claimed in any one of Claims 1 to 8 wherein the fluid comprises a liquid and the step of applying the treatment liquid comprises contacting the surface of the hide with a liquid bearing applicator.

12, A process as claimed in Claim 11 wherein the liquid bearing applicator comprises a porous compressible applicator bearing the liquid, the applicator being compressed under pressure against the hide surface so that the liquid held by the applicator is applied to the hide surface.

13. Apparatus for treating a hide with a treatment fluid, the hide when spread out to lie in a plaie having a longitudinal dimension and a transverse dimension and a centre line extending along the length thereof in said longitudinal dimension, the apparatus comprising: stretching means for stretching the hide so as to simultaneously extend the hide in both the longitudinal dimension and the transverse dimension and thereby render the hide in a stretched condition, the hide in said stretched condition being extended in both the longitudinal and transverse dimensions to an extent sufficient to open the hide structure and promote penetration of said Lyreatment fluid into the hide as a result of the opening of the hide structure, said stretching means comprising engagement means to engage the hide at a plurality of engagement points including multiple engagement points spaced apart and located on opposite transverse sides of said centre line and multiple engagement points which are spaced apart in the longitudinal dimension, said stretching means further including means for applying stretching forces to the hide at said engagement points, the stretching forces including stretching forces applied in both the longitudinal dimension and the transverse dimension so as to thereby simultaneously stretch the hide in both those-dimensions and thereby open the hide structure, and fluid applying means operative to apply said treatment fluid to the hide at least where the hide is in said stretched condition in 30 both the longitudinal dimension and the transverse dimension so that the fluid penetrates into thc opened hide structure.

14. Apparatus as claimed in claim 13 wherein said multiple engagement points are dispersed throughout substantially the entire surface area of the hide so that the stretching of the hide to open the hide structure occurs throughout said surface area of the hide.

Apparatus as claimed in claim 13 or 14 wherein said fluid applying means is operative to apply said treatment fluid to the hide \jv C; 16 simultaneously with and during the process of stretching of the hide in the longitudinal and transverse dimensions by said stretching means.

16. Apparatus as claimed in any one of claims 13 to 15 wherein said stretching means comprises an upstream set of cooperating nip rollers between which the hide is passed, and a downstream set of cooperating nip rollers between which the hide is passed, the upstream and downstream sets of nip rollers being separated in the longitudinal dimension of the hide by a distance such that the hide is simultaneously in both sets of nip rollers, the downstream set of nip rollers being driven at a greater speed than the upstream set of nip rollers so that when the hide is being passed therethrough, the hide is stretched in the longitudinal dimension as a result of the speed difference, said downstream set of nip rollers comprising a left side pair of downstream nip rollers and a right side pair of downstream nip rollers, the axes of the left and right side pairs of downstream nip rollers being non-colinear and at least one of said pairs of downstream nip rollers having its axis angled at an acute angle to the direction of a line from the downstream set of nip rollers to the upstream set of nip rollers so as to be operative to stretch the hide in the transverse dimension as it passes to and through the downstream nip rollers, said fluid applying means being operative to apply said treatment fluid to the hide in the space between the upstream and downstream sets of nip rollers while passing therethrough and where the hide is being stretched.

17. Apparatus as claimed in Clasim 16 wherein the left side and right side pairs of downstream nip rollers are each arranged at an angle of between 70' and 87 to the longitudinal dimension of the hide. 30

18. Apparatus as claimed in any one of claims 13 to 15 wherein said engagement means comprises at least two clamping means for clamping the hide at multiple points including points spaced apart in the longitudinal dimension of the hide and points spaced apart in the transverse dimension of the hide, the stretching means further including moving means for moving the clamping means relatively apart in both the longitudinal dimension and the transverse dimension, whereby the movement of the clamping means increases the separation of the clamping points which are spaced apart id the longitudinal I- dimension thereby causing stretching of the hide in the longitudinal dimension, and whereby the movement of the clamping means also increases the separation of the clamping points which are spaced apart in the transverse dimension thereby causing stretching the hide in the transverse dimension.

19. Apparatus as claimed in Claim 18 wherein some of said multiple points are nearer to the centre line than others and the points nearer to the centre line are relatively moved apart by said moving means to a lesser degree than the clamping points further from the centre line.

Apparatus as claimed in Claim 19 wherein the multiple clamping points on each side of the centre line lie in a respective general line extending away from the centre line at an acute angle to the general centre line, the clamping means being movable by the moving means so as to increase the angle to the centre line towards 90' and thereby stretch the hide in the transverse dimension between the clamping points on opposite sides of the centre line.

21. Apparatus as claimed in Claim 20 wherein the clamping means comprises pairs of respective upper and lower clamping edges co-operable to clamp and hold the hide between the respective edges, each of adjacent pairs of respective edges on the opposite sides of the general centre line defining a shallow V-shape, the moving means being operable to move the clamping edges with a hinging movement so as to cause the shallow V-shape to approach a straight line.

22. Apparatus as claimed in Claim 21 wherein the clamping means comrprises a plurality of adjacent spaced generally parallel sets of co-operating upper and lower clamping edges, the fluid applying means being located between adjacent sets of clamping edges,

23. Apparatus as claimed in any one of claims 18 to 22 and further inicluding conveying means for conveying the hide to a stretching and treatment station where said stretching means and said fluid applying means are provided, the conveying means being further operative to convey the hide after treatment at the stretching and treatment station away from that station.

24. Apparatus as claimed in Claim 23 wherein said conveying means comprises a conveyor composed of a plurality of strands extending in said longitudinal dimension on which the hide is carried, the strands 18 being movable apart laterally during operation of the stretching means to effect stretching of the hide in the transverse dimension. Apparatus as claimed in Claim 24 wherein the clamping means comprises a lower clamping edge engageable with an undersurface of the hide, the clamping edge having a plurality of notches therein, the strands of the conveyor passing through the notches so as to be movable apart as the angle of the clamping edge to the general longitudinal line of the strands changes from an acute angle towards an angle of 90