CA1127810A - Method of extracting meat of small crustaceans and apparatus for performing this method - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A method of extracting meat of small crustaceans which includes operations performed in the following succession:
- introducing said crustaceans into a flow of a working agent which breaks up the shell and separating it from meat by making said flow of the working agent move relative to the surface of said crustaceans at a given velocity sufficient for creating a pressure differential between the internal space of said crustaceans and said flow of the working agent.

Description

METHOD OF EXTRACTING MEAT O~ SMAL~ CRUSTA-CEANS AND APPARA~US FOR PERFORMING ~EIS
M~3THOD

The present invention relates to the technology of proce~sing sea~living-organisms into ~ood produots, and more particularly it relates to a me-thod o~ e~tracting meat o~ small crustaceans and to an apParatus capable o~ perform-ing this method.
Although the invention is particularly designed for treating an-tarctic small shrimps or krill~ it may be also utilized by the ~ishing industry ~or trea-ting sea- and ocean-living shrimps. Furthermore, the invention can be utilized by various branches of the agricultural production and ~odder i nduS trD ~
Antarctic krill presents one o~ the most practical large-~oal~ sourc~s o~ considerable expansion o~ the suppl~
of protein-containing food o~ animal originO The total cat-ches of krill may well s~pa~s -~he presently attained -total level o~ the catches o~ fish in the World Ocean. The most valuable component o~ krill is i~5 pure meat in the form o~ a lump o~' muscular tissue, the chemical composition o~
l~rill meat being close to that of crab and shrimp mea-t, containing a3 it does numerous vital amino-acids ~nd micro-element~. ~or krill meat to be used as a food ~or humans, ~ "

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it has to be completely separated from the shell or crust.
Moreover, pure meat recovered ~rom krill must have -the mi~
nimum conte~t o~ lipides, must be ~ree ~rom the liver remnan~s a~d from the contents o~ the gastrointestinal tract, which matter a~ects the quality o~ the pro~uct and curtails its permissible storage time.
Taking into consideration tha-t more often than no~
krill is caught in areas which are far away from the places o~ its consumption and that its transportation to these places o~ consumption takes a relatively long time, it is e~pedient that krill should be processed directly where it is caught into pure meat presenting a ready-to-use product, e.g. canned natural meat, or else into a semi-~inished product, e.gO deep-~rozen pure meat.
Known in the art is a method o~ separatin~ the mea-t o~ crustaceans ~rom the shell or crust, i~cluding loading the crustaceans, forwarding them along a helical duct, break-ing ~he shell with rotatin~ discs having sharp burrs on t~eir peripheries and ~eparating the meat ~rom the ~hell ~ragme~ts by flotation.
When shrimp is processed by this known method, the meat i~ recovered i~ individual lumps; however9 there takes place considerable de~ormation and disintegration o~ these lumps, which af~ecta both the quality and appearance o~ the ~7 ~

~inal produc-t. Moreover, the k~own method is intended for - processing s~lrimp of a relatively large size and is impractic-al ~or removing the shell o~ small crustaceans, e.gO krill.
~ here is ~urther known a method of separating the head o~ a shrimp ~rom the body thereo~ by destroying the ~ies betwsen the head portion and the body o~ a high-velocity ~luid ~low or jet. The essence of this method consists in ~ol-lowing. A shrimp is positioned so that its head and body are introduced into a high-velocity water jet, the area o~ the conneation o~ the head portion with the body being positioned adjacent to t~e edge o~ a stationary elemen~. The ef~ort be-in~ created by the high-veLocity fluid jet is direoted either at the head or at -the body portion o~ the shrimp, whereby t~e head and the body become separated.
~ he last-described known method per~orms but some o~
t~e operations making up the technology of e~tractin~ the meat and separating it ~rom the shell, namely, the operations of ~eparating the heads o~ crustaceans from their bodies. '~he rest o~ the operations involved in breaki~g up the shell~
e~tracting the meat and ~eparating o~e ~rom tho ot~er are per~ormed b~ other methods.
Thus, the last-described know~ method would not en-able to obtain pure meat, while the repeated operations of extracting the meat from t~e body and separating the com-, ' , ' ~ `~ ;` ' ~.

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pone~ts inflict inevi~able losses and affect the taste o~the final product, on account o~ the latter's prolonged contact with the ~luid~
The last_described known method is likewise designed ~or treating relatively large shrimps and is impractical ~or treating krill~ ~urthermore, the one-by-one technique o~ treating shrimps es~en-tially curbs down the productivity o~ the method.
There is ~urther known a method o~ removing the shell lo o~ crustac~ans9 e.g. crabs9 including one by-one treatment o~ crustaceans by carrying them i~ an air ~low past blade-like teeth and scrapers, in which manner mechanical removal o~ the shell o~ the crustaceans is e~fected.
This last-mentio~ed known method also includes class-i~ying the crustaceans to be -treated into ~raations accord-ing to siz~, indexing the crustaceans and treating them one by on~ within each ~raction.
~ he above operations are labour-co~suming; they compli ca~e the technology and limit the productivity. Besides, the method would not provide for destroying such components as the liver and the gastrointestinal trac-t, so that pure meat c`annot be obtained~ With the technique being designed for treatment of large crustaceans, it oannot be employed ~or treating antarctio krill.

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Thus, the hitherto known methods of treating crusta-ceans, although they solve the problem of obtaining edible pro-duct to a di~er~nt degree, are impractical ~or treatin~
small crustaceans, e~g. antarctic krill. These methods pos-sess limited possibilities o~ ob-taining pure meat from cru-staceans and would not enable to introduce a~ automated high-ly e~ficient technology of treating small sea-living crusta c~ans in bulk~
There is known an apparatus for removing the shell ~rom crustaceans, including a belt conveyer`; a spiral or helical duct and a rotary disc provided with sharp points on its periphery.
The apParatus operates, a~ ~ollows. The belt conveyer charges crustaceans into -the inlet funnel O:e the spiral duct.
The action o~ the rotating disc forwards the crustaceans with acceleration alon~ the predetermined patn, while the sharp points o~ the rotating disc cut in-to the sur~ace o~
- the shell and destroy the lat-ter. ~hen the meat and the shell fragments are separated by flotation.
~his known apparatus enables to obtain shrimp maat in individual lumps; however, these lumps are intensely dis~
integra-ted, which involves substantial meat losses. ~he ap -paratu~ is inte~ded for treating shrimp o~ a relatively lar~
~ize, which re~ders i-t impractical ~or r~moving the shell o~ small shrimp9 e~g. antarctic krill.

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~ here is known a range of apparatus for separating ~he heads o~ s~imps .rom their bodies, including a charging ~nnel, a shrimp treatmen-t chamber accommodating a stationar~
cutting member and pipes for feeding the working fluid.
In this known type o~ appara-tu9 shrimps are ~ed o~e b~y one into the charging funnel wherefrom each successive shrimp is directed through a guide channel into the treatment chamber where it is subjected to the action of a high-velo-city fluid jet, the area o~ the connection of the head por-lo tion o~ the shrimp with the body -thereo~ being positioned adjacent -to the edge of the stationary cutting member, and the ef~ort created by the said high-velocity ~luid jet be-ing directed either at the head or the body portion, where-by the head and the body become separated.
~ he hitherto known appara-tus per~orms but some of the operations of the technology o~ trsating orustaceans, namely, the separation o~ the head from the body~ ~he successive ope rations of breakin~ up the shell and e~tracting the meat are performed by other apparatuses, while -the repeated operatio~s invariably in~lict additional meat losses and affect the taste of the ~inal produc~ on account o~ i~s prolong~ed con-tact with the ~luid.
Furthermore~ the apparatus of the last described known type is intended ~or treating large shrimp and ca~ot be employed for treating krill. Besidss, the one~b,y one treat-.

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781l0 ment of shrimps affects the produc-tivity? iS labour-consum~
ing and uneconomical.
~ here is still further known an apparatus for e~tract-ing meat of' crustaceans, comprising a chargingr mechanism and a mechanism for breaking up the shell and separating it from meat, including a plain-wall bent pipe wi-th a straight portion and an inlet pipe for feeding the working agent.
~ he charging mechanism includes a longitudinally runn-ing belt conveyer o~` which the load~supporting sur~ace is inclined to both sides o~ thce longitudi~al axis toward the edges. Arranged alongside of thc~ conveyer belt are progres-" sively broade~ing horiæon~al classifying slits, each slitbeing adjoined by an inclined indexing ~rough.
~ he mechanism for brsaking up the shell and separat-ing it from meat is in the ~orm o~ an i~let bellmoutn adjoin~
ed by a tubular duct of an oval cross-section corresponding by its shape to the general contour of the crustaceans; lead-ing tangentially into the duct is an inlet pipe ~or ~eeding the working~ agent9 e.g. compressed air; the s-traight portion of the duct accommodates means for breaki~g and removing the s'nell, including blade-shaped teeth and scrapers project-ing into the passag~, not unlike the jaws of a pike. Mounted in the duct upstream of the inleu pipe for feeding the work-ing agent are compressed-air shutters ~e~ining a sluice-type . , . , ~ 127B ~0 c~amber.
The apParatus operates, as ~ollows. Crustaceans, e.g.
crabs are ~ed onto the horizontal run o~ the conveyer belt .vhere they slide b~ gravity sideways and are carried past the progressivel~ broadenin~ horizontal slits, in which wa~
they are classi~ied according to size; the smaller species being the ~irst to be let in by these slits and thus to be separated ~rom the bulk. While sliding down the inclined downward trough, the crabs are inde~ed and guided into the mechanism ~or breaking up the shell and separa-ting it ~rom meat. In this mechanism the crabs indexed to the predetermined attitude are first directed in-to the inlet bellmouth, then made to pass by the compressed-air shutters, and then are tak-en up by the ~low o~ compressed air which carries them one by one through the straight portion o~ thc tubular duct. With-in this portion the crabs enoou~ter the blade-like teeth which cut and break the shell, while the scrapers scrape it o~f -the bo~ies ol the crustaceans. ~hen the crabs stripped o~ the shell are directed together with the shell ~ragments into an air-blowin~ device where pure lumps o~ meat are re- ;
covered by win~owing.
Althou~h the known apparatus ena~les to obtain the mea-t o~ crustaceans in lumps, i-t cannot be used ~or treating small crustaceans, such as krill, for a number o~ practical ,~

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reasons.
This known apparatus has been devised ~or extracting rl~eat oi large crustaceans. '~he necessity o~ classiYying the crustaceans by size and feeding them ~or treatment in the one-by-one Yashion sharply a~'ects the throughpu-t of tne ~pparatus. ~l~ith the inlet pipe ~or ~eeding co~pressed air being arran~ed tangentially, a portion of the air ~low is re~lected by the walls o~' the straight portion o~ the tu`bu-lar duct and ~lows in a counter-current r~lative to the advance of the crustaceans directed ~or treatmcnt, this counter-c~rent impeding ~he motion o~ the crustaceans along the bent pipe, For this reason the known apparatus incorpo-rates the shutters de~ining the sluice-like chamber to mini-mize -the in~luence of the above penomenon. However, the pre-sence o~ these shutters is in itsel~ an impediment to the advance oY the crustaceans and involves the haæ~rd o~ the inlet bellmouth becoming clogged wi-th the crustaceans, to say nothing o~ the throu~hput and reliability o~ the perfor-mance Or the apparatus being a~ected and its str~cture be~
ing complicated.
~ he cross-sectional shape o~ -the tubular ducts has to be ~inol~ ~natched to the size o~ each classi~ied ~ractio~
OL' the crus-taceans, which ~urther complicates ~he s-tructure oY the apparatus.

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Besides, -the blade-shaped ~eeth arrang~ed within the straight por-tion of the tubular duct display a tendenc~
OL damaging the lumps o~ the meat o~ the crustaceans, of affectinp~ their integrity and of increasing the loss rate, whereas the scrapers s-tripping o~f the shell become eventually clo~5ge~l witl~ the si~ell ~ragments, which a~fects -the conti~
LlUOUS reliable performance o~ the apparatus and complicates the sanitary treatment.
The ~ain object o~ the present invention is -to provide o~ a method and apparatus ~or e~tracting meat of small crus-t-aceans -throughout the entire size range constituting -their catches, which, by emplo~ing the novel physical phenomena o~ e~erting action upon the crustaceans, should enable to obtain pure mea-t containin~ -the minimized amount of lipides and impul~ities, without any pre--classification and pre-in~
de~ing of the crustaceans~
This objec-t is a-ttained in a method o~ extracting meat of small crustaceans by introducin~ the latter into a work-- in~ agent, which method, in accordance with -thc present ~.
in~ention, includes breaking up -the s~ell and separating the latter from meat by moving t~e working agent relative to the surface of the crustaceans a-t a given velocity required for creating a pressure differential between the internal cavity or space of the crus-taceans and the flow of the work-,, ~. ~
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--ll in~g ag~nt.
~'he worhi~6 agent may be air which is expedient to be used ~or separating the components o~ the crustaceans in a s-tage--wise fashion. It is expedient to move the air relative to the surface of the crustaceans during the ~irst -treatment stage at a velocity subs~antially equal to 500 metres per second, in order to separate the chitinous portions and bO
sever the tias between the gastrointestinal tract and the muscular tissue; it is ~urther expedient to move it during the second treatment stag~ at a velocity substantially wi-th-in the range ~rom 200 to 300 m/~ to sever the ties between the cephalothora~ and the muscular tissue and to partly se-parate the latter; it is still ;~urther expedient to move tha air at thc third stage at a relative veloci-ty within the range ~rom 100 ~o 200 m/s to separate th~ muscular tissue :~rom the cephalothorax completely.
- Alternatively, the working agent may be ~luid which is pre~erably mov~d relative to the surface o~ the crusta- -ceans at a velocity ~rom 10 to 30 m/s~ ;
~o e~ect ~inal severing o~ the ties between the mus- ;
cular tissue and the liv~rg it is e~pedient to have the work-ing agent ~lowing at the ~inal treatm0nt stage along a heli-cal path relative to the surfac~ o~ the crustacsans~

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.12-The object of -the present invention is also attained in an appara-tus ~or extracting meat of small crustaceans, such as antarctic krill, comprising a charging mechanism and a mechanism fQr breaking up the shell and separating it from the meat, including a bent plain-wall pipe with a s-traig~lt portion and a connection ~or ~eeding the working agent, in which apparatus~ in accordance with the present inven-tion, the connection for ~eeding the working agent in-cludes a jet nozzle coaxial with the straight portion OL
the plain--wall bent pipe, the straight portion being coupled by a helical duct termina~in,c3 in a di~fuser~
It is expedient -that the helical duct should include a tube accommoda-ting therein a spring of which one end is connected with the straight portion of the plain-wall ben~
pipe and the other end i5 connected with the diffuser, the portion of the spring, adjoining the plain-wall bent pipe, including -turns spaced from one another, and the tube havi~g a cutaway portion in the same area.
Tha prese~t invention will be further described in connection with examples and embodiments proving the practi-cability ol e~fecting the disclosed method o~ extracting ~eat o~ small crustaceans, and with the accompanying drawing illustrating~ schematically an apparatus for extracting meat o~ small crustaceans, embodying the invention.

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The disclosed method o~ extracting meat Or crusta-ceans is based on the physical phenomena o~ e~erting action upon the crustaceans by a flow o~ a working agent or lluid rnoving at a given velocity relative to the surface o~ the crustaceans.
A l~rill species includes a closed shell or crust ac-commodating therein the muscular -tissue connected to ~his shell, the liver accor~modat-ed within the cephalothorax, the gastrointestinal tract and other components. ~he major por-tion o~ the lipides in the krill species is in the liverand in the connec-tion tissues adjoinin~ the shell.
~'he essence o~ the disclosed me-thod is, as ~ollows.
While the working agent moves relatively to the krill, there is created suction or negative pressure at its sur~ace, whereby` the internal pressure becomes highor than -tha-t at -the sur~ace o~ the krill. Under correspo~ding conditions ~his e~cessive pressure becomes su~icient ~or destroying the shell, the liver, the gastrointestinal tract, and also ~or destroy~
ing and severin~ o~ -the ties between the muscular tissue and the shell. ~he muscular tissue~ being as i-t is the s-trongest component, remains an integral lump during this operation and becomes relieved of the rest o~ the components containing a substantial amount o~ lipides.

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'~he ~etnod is effected, as follows. ~rill within a size ran~e from 25 to 60 mm~ which is practically -the entire size range of krill being caught, is directed in bulk, with-out any ~re-classification by size and pre-indexing, into the flow O:e the working agent which may be either air or fluid.
~ he treatme~t o~ krill wi-th air is pre~erably effected in successive stages. During the ~irst stage the air is Made to ~low relative to the sur~ace of the crustaceans at a ~elocity substantially equal to 500 m~s to separate the chitinous portions and to sever the ties between the gastro-intestinal tract and the muscular tissue; durin~ the second stage the air i5 made to ~low at a relative velocity ~rom 200 to 300 m/s to sever the ties between the cephalothora~
aLld the muscular tissue and to partly separate the la-tter;
during the third stage the air is made to ~low at a relative velocity ~rom 100 -to 200 m/s to separate completely the mus-cular tissue ~rom the cephalothora~.
~ ,Vhen krill is treated with a fluid, it is pre~erably made to flow relative to the sur~ace o~ the crustaceans at a velocity substantially ~rom 10 to 30 m/s.
During the final treatment stage the working agent is pre~erably made to ~low rela-tive to the surface o~ the crustaceans along a helical path, to ensure intense turbulis-ation o~ the working agent and o~ the crustaceans within the curvilincar ~low, so that complete separation and se-verin~ oE thc ties between the muscular tissue and the liver, the ~astrointestinal tract and the rest of the components o~ the krill should take place.
During each stage o:~ the treatment with air and during the -treatm~nt with a ~luid the respective velocities may be varied within the abovespecilied ranges in dependence on the ph~sical and chemical conditions o~ the initial stock, ~;
its size and ot-her ~actors.
10'l'he ~inal sepaLa-tion of the muscular tissue ~rom the shell, the remnants o~ the liver, the gastrointestinal tract and other ~oreign matter is e~ec-ted by subsequent ~lushing, ~,Tinnowing or ~lotation. ~he yie:Ld o~ pure meat amounts to 22 to 26 per cent by mass o~ the initial stook.
~ he practicability ol the herein disclosed method will be substantiated by the follo~ving examples.
Example 1 Antarctic krill o~ a size from 25 to 35 mm is directed ~;~
in bulk, without any preclassi~ication and preindexing, into an air aet ~low movin~; at a velocity o~ 500 m/s relative to the sur~ace o~ the crustaceans, so tha-t practically instantly the shell or crus-t becomes broken up, and the ties between the muscular tissue and the liver and ~astroint~stinal tract ; ~; . i t . , ~16_ .

becorne severed. '~hen the partly broken up kril' is subjected to the second sta~,e of the action thereupon o~ an air jet L low rnoving along a helical path, its velocity relative to the sur~ace ol ~he crustaceans equalling 200 m/s. At this stage the ties between the cephalothorax and the muscular tissue become severed, and the latter is completely separated ~rom the cephalothorax. 'r'he pure meat is recovered by ~lotation.
'~he yield o~ the pure raeat amounts to 22 per cent by mass o~
the initial stock~
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Antarctic kriil of a size ~rorn 30 to 45 mrn is directed in bulk, without preclassi~icat.ion and preinde~i.ng, in-to an air jet ~low moving relative to the sur~ace o~ the cru-staceans at a 500 m/s velocity, whereby the destruction o~ ~.
-ttle shell and the severi~g o~ the ties betweerl the muscular tissue and the liver and gastrointestinal tract take placé
practically instan-tly. A-t the second treatment stage the par-tly destroyed L{rill is subjected to the action thereupon o~ an air jet ~low moving at a velocity o~ 250 m/s relative to the surface o~ the crustaceans. At this stage the ties between the cephalothora~ and the rnuscular tissue become se-vered~ a~d the latter is partly separated. '!'hen the prodùct is subjected ~o the action of an air jet flow moving at 100 m/s

2 7 velocit~ relative to the sur~ace o~ the crustaceans. At this stage the muscular tissue becomes completely separated from the cephalothora~. During the second and third treatment stages the air jet flow is made to move along a helical path.
'~he recovery o~` the pure meat is effected by win~owing. The yield o~ the pure meat anlounts to 24 per cent by mass o~ the nitial stoGk.
xam~e 3~
Antarctic krill o~ a size from 40 to 55 mm is directed in bulk, without any preclassi~ication and preindexin~, into an air jet 9 ~low moving at 500 m~s velocity rela-tive to the sur~ace o~ the crust~aceans, ~hereby practically instantly the shell becomes broken up, and the ties between the mus-cular tissu~ and the liver and ~sas-trointes-tinal tract become severed. At the second sta~e o~ the treatment tne partly destroyed krill is subjected to the ac-tion o~ an air jet flow moving relative to the sur~ace o~ the crust~ceans at a 250 m/s velocity, whereby the ties betwee~ -the cephalothorax and the muscular tissue are severed, and the latter i9 partly separated~
r~hen the product is subjected to the third stage of the ac-tion thereupon o~ an air jet ~low moving relative to the sur-~ace ol the crustaceans at a velocity of 150 m/s. At this stage -the muscular tissue i5 completely separated ~rom the ce-- phalothorax. Durin~ the second and third treatment stages ~; ` ' ' , ~ :
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the air ~low is made to move along a helical path. The re-covery o~ the pure meat is ef~ec-ted by winnowing. The yield o~ the pure meat is 24.5 per cent by mass of the initial stock.
hxarn~le ~
Antarctic krill o~ a size from 45 to 60 mm is directed in bulk, without any preclassi~ication and preindexin~, into an air je-t ~low ~oving relative to the sur~ace o~ the cru-staceans at a 500 m/s velocity. The shell is thus broken up, and the ties between the muscular tissue and the liver and gastrointestinal tract become severed. A-t the second s-tage o~ the trcatment -the partly destroyed krill is subjected to the action o~ an air ~low movin~ relative to the sur~ace o~
the crus-taceans at a velocity of 300 m/s. ~his -treatment severs the ties between the cephalothora~ and the muscular tissue and partly separates the latter. Then the product is subjected to the third stage of trea-tmen-t b~ the action thereupon of an air jet flow moving relative to the surface of the crustaceans at a 200 m/s velocity. At this stage the muscular tissue is completely separated from the cepha-lo-thora~. During the second and third treatment stages -the air ~low is made to move along a helical path. The recovery of pure meat is ef~ected by flo-tatio~. ~he yield of the puxe meat amounts to 26 per cent by mass o~ -the initial stock.

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~'~{a.Mple ,~ ~
Antarctic krill of a size ~rom 25 to 40 mm is directed in bulk, ~lithout any preclassification and preindexi~g, into a water ~low moving relative to the surface of the crust-acea~s at a veloci ~ of 10 m/s. With the high-veloci-t~ wa-ter flow flowil~g about the krill, there is created suction or - negative pressure at the surface of the crustaceans, acting to break up the shell, sever its ties with the meat, sever -the ties between the cephalothora~ and the muscular -tissue a~d the ties between the latter and the gastroin-testinal tract. As a result, a pure lump of meat is separated ~rom the rest o~ the components of the krill. The efficiency of the above processes is enha~ced by the water flow moving along a helical path. ~he recovery of the pure meat is effected by ~lushin~ on a per~orated sureace. ~he yield of -the pure meat amounts to 24.5 per cent b;y mass of the initial product.
ExamP-le- 6.
Antarctic krill of ~ sizo ~rom 40 to 60 mm is directed in bulk, withou-t any preclassi~ication and preindexing, into a water ~low movin~ at a ~0 m/s velocity relative to the sur-~ace of the crustaceans. With the high-velocit~ water flow ~lowin~ about the sur~ace of -the crustaceans 9 there is created - at this surface the suction or negative pressure which ac-ts to break up the shell and sever its ties wi-th the meat, to : , ,. : . .: .

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7 ~0 sever t~e ties between the cephalothorax and the muscular tissue and the ties between -the latter and the gastrointestinal tract. As a result o~ the treatment, a lump of pure ~uscular tissue is separated ~rom the rest of the components o~ the krill. ~he e~iciency of the above processes is e~hanced by the water flow being made to flow along a helical path~ The recovery o~ the pure meat is effected by ~lushing on a per-forated sur~acc. The yield of the pure meat amounts to 26 per cent by mass of the initial stock~
'~e herein disclosed method of extractin~ m~ak o~
small crustaceans enables -to ob-tain new kinds of edible products o~ animal origin ~rom antarctic krill which is a new unorthodo~ source o~ sea-provided ~ood. ~he method makes it pos~ible to extract krill meat oontaining no liver remnants, lipides 9 gastrointestinal tract and other impuritiesO With the krill meat thus obtained being devoid o~ the liver and - containing the minimum amount o~ rapidly o~idizing lipides, it would no~ change its colour, ~lavour or tas~e duri~g the sub sequent thermal treatment, e~g. ster~ization, which prolongs the permissible storage time ol any ~oodstuf~ that can be produced from the krill meat, particularly, o~ canned ~oo~
~ he employment o~ method o~ the present invention en-ables to introduce simple and economically effective techno-lo~jy of treating sm~ll crustaceans, and to set up the treat-. . ~

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ment.o~ krill in bulk on the industrial scale~
The implementation o~ this me-thod either on vessels in the catching areas or in land-based ~actories opens up ~ine prosp~cts of contributin~ to the solution of the im-portant problem o~ providin~ humans with a high-quality ~ood rich in proteins o~ the animal origin.
. An apparatus ~or e~tracting meat o~ small crustaceans, embodying the present invention and illustrated in the ap-pended drawiLl~, includ~s a charging or loading mecha~ism 1 o~' any suitable l~nown per se type, c.~. a belt conveyer or '' a worm screw feeder. Adjoining this charging mechanism 1 is '~
a mechanism 2 for breaking up the shell and separating t~e latter ~rom meat, including an i.nlet bellmouth 3, a plain--wall bent pipe ~ wi-th a straigh~ portion 5, a connection 6 ~or ~eeding the workinO agent, i.ncluding a jet nozzle 7 co-axial with the stràight portion 5, the latter having connect- ;~
ed tnereto a helical duct structure 8 terminating in a di~-~user 9. The helical duct structure 8 ineludes a tube 10 ac; :~
commodating therein a spring 11 o~ whieh one end is conneeted to the straight portion 5 o~ the plai~-wall bent pipe 4/
wnile its other e~d is conneeted to the di~user 9. ~he -turns o~ the spring 11 in the area 12 adjacent to the plain~wall '~
bent pipe 4 are spaced ~rom ona another, while the -tube 10 ., .

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has a cutaway portion 13 in ~he same area 120 The working agent feed connection 6 is connected to a worki~g fluid source 14.
The apparatus operates, as ~ollows.
~ e bulk o~ krill is ~ed from the charging mechanism 1 into the inlet bellmouth 3 o~ -the mechanism 2 ~or break- -inp, up the shell and separating it ~rom meat, t~e mechanism 1 providing uni~orm metered-out ~eed of krill. ~he working a~ent ls ~ed ~rom the v~orking ~luid source 14 through the connec-tion 6 and the jet nozzle 7 at a high velocity into th~ straight portion 5 oY the plain-wall bent pipe 4, where-~rom it ~lows into the helical duct 8 and the di~user 9.
'~he jet nozzle 7 being arranged coa~ially with the straight portion 5, any re~lection o~ the flow o~ the working agent by the walls o~ the straight portion 5 and o~ the helical duct 8 is precluded, whereby there is no counter-current o~ the workin~ agent in the plain-wall bent pipe 4, which co-unter-current could have impeded the progress o~ krill in the mechanism 2.
~he jet oi the working agent creates suction or nega- :
tive pressure in the plain~wall bent pipe 4 and in the in-let bellmouth ~, whereby air is drawn by aspiration into the inlet bellmouth 3, so that krill iB sucked in through the bellmouth 3 into the mechanism 2.

-.;
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:~ ' ~ ' :'' :"

~ :

With the high-velocity jet flow o~ the working agent flowi.nr~ about the sur~ace o~ the krill within the straight portiOn 5; there is created negative pressure at the sur~ace o~ the krill, whereby the internal pressure o~ the krill breaks up the shell and severs the ties between the muscular tissue and the liver and gastrointestinal traat, and also severs the ties between the cephalothora~ and the ~nuscular tissue and partly separates the latter. The abovesaid pro-cesses take place practically instantly and simultaneously.
~hen the krill is adva~ced by the ~low o~ the working agent into the sprin~; ll of the helical duct 8, where -the abovedescribed action o~ the working agent upon the krill, assisted by intense turbulisation of the ~low of the wor~-ing agent and by friction developed between the krill species in the curvilinear ~low, e~eots complete severing of the ties between the ephalothorax and tne muscular tissue and relieves the pure meat o~ the cephalothora~ and other com-ponents.
he Oæen area 12 o~ the spring 11, commu~icating with the ambient atmosphere via spaces between the turns o~
the spring 11, reduaes the ~low resistance o~ the helical duct 8 and provides ~or sucking-in o~ additional air by aspiration, which prevents clogging o~ the inlet bell~outh .
'. ... : ~ .

. ~

11 ~ 78 ~0

3 ~th the product.
~;~;ith the spring 11 being accommodated within the tube 107 the tube 10 havin~ the cutaway portion 13 and the ends o~ the spring 11 being connec-ted wi~h -the straight portion 5 and the di~user 9, there is promoted a directed ~low o~
the working agent and there is precluded any eventual clog~-ing o~ the helical duct 8 with the product being trea-ted.
From the helical duct 8 the product being treated advances into -tne di~user 9 wherein the velocity o~ the ~Yorking a~3ent ~low is sharply reduced, so tha-t the difIJer-ence between the amounts o~ the kinetic energy stored by the heavier components o~ krill~ i.e. -the muscular tissue and cephalothorax, and by its lighter components, i.e. the s~ell ~ragments9 liver, legs, etc., results in partial se paration OL the componen-ts o~ -the krill, which are directed ~or ~urther treatment to e~ect the recovery o~ the pure meat and the separation o~ the was-te.
~`he herein disclosed apparatus i9 characterized by - a high throuKhpu-t and is capable of trea~ing t`ne entire size ~;
range o~ small crustaceans without preclassi~ication and pra-inde~ing. Those competent in the art will appreciate the sirnplicity o~ the s-tructure o~ the apparatu5 9 it9 accessibi-lity ~or rnaintenance and sanitary -treatment, . ~ . ' ,~

~ he apparatus is devoid of s~arp balde-like -teeth and sCrapers 9 which enables to recover pure mea~ with minimized disintegra-tion, and, therefore 7 wi-th the minimum waste.
T~e apparatus makes it possible to recover p~re meat ~rom small crustaceans, the meat baing valuable protein-cont-aining ~ood o~ animal or~gin, whereas the shell can be usod eor ob-taining chitin and chitasine for technical purposes.
~he rest of the waste can be processed into valuable animal ~eed products.
~he apparatus enables to at-tain the yield of -the pure meat as high as 22 to 26 per cent by mass.
Since krill is caught nowadays in ~reat volumes, the implemen-tation o~ the herein disclosed invention is both prac-tical a~d economically e~ec-tive.
~ e implemen-tation o~ the presen-t invention on an industrial scale will enable to introduce into practice composi~e processipg o~ krill, ~o derive ~rom it hi~h-qua-lity foodst~ees suitable for prolonged ~torage~ e.g. canned ~ood 9 and also to ob-tain valuable technical and animal ~eed products.

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Claims (10)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of extracting meat of small crustaceans, including operations performed in the following succession:
introducing said crustaceans into a flow of a working agent; breaking up the shell and separating it from meat by making said flow of the working agent move relative to the sur-face of said crustaceans at a given velocity sufficient for creating a pressure differential between the internal space of said crustaceans and said flow of the working agent.

2. A method of claim 1, wherein said working agent made to move at said preselected velocity is air.

3. A method of claim 1, wherein said working agent made to move at said preselected velocity is fluid.

4. A method of claim 1, wherein said working agent is made to move relative to the surface of said crustaceans along a helical path.

5. A method of claim 2, wherein said breaking up of the shell and its separation from meat is performed in successive stages, said preselected velocity of said motion of said flow of the working agent, which is air, relative to the surface of said crustaceans being set at different values during the different ones of these stages.

6. A method of claim 3, wherein said flow of the working agent, which is a fluid, is made to move relative to the surface of said crustaceans at a velocity substantially within the range from 10 to 30 m/s.

7. A method of claim 5, wherein during the first stage of the treatment of said crustaceans, including separation of the chitinous portions and severing of the ties between the gastrointestinal tract and the muscular tissue, said preselected velocity of said motion of air relative to the surface of said crustaceans is set substantially equal to 500 m/s, during the second stage including severing of the ties between the cephalo-thorax and the muscular tissue and the partial separation of the muscular tissue, said preselected velocity of said motion of air relative to the surface of said crustaceans is set substantially within the range from 200 to 300 m/s, during the third stage including complete separation of the muscular tissue from the cephalothoxax, said velocity of said motion of air relative to the surface of said crustaceans is set substantially within the range from 100 to 200 m/s.

8. An apparatus for extracting meat of small crustaceans, comprising a charging mechanism and a mechanism for breaking up the shell and separating it from meat; a plain-wall bent pipe of said mechanism for breaking up the shell and separating it from meat, having a straight portion; a connection for supplying the working agent of said mechanism for breaking up the shell and separating it from meat, including a jet nozzle coaxial with said straight portion of said plain-wall bent pipe, a helical duct connected to said straight portion of said plain-wall bent pipe;

a diffuser connected to said helical duct.

9. An apparatus of claim 8, wherein said helical duct includes a tube accommodating therein a spring of which one end is connected to said straight portion of said plain-wall bent pipe, the other end of said spring being connected to said diffuser.

10. An apparatus of claim 9, wherein said spring includes turns spaced from one another in an area adjoining said plain-wall bent pipe, said tube of said helical duct having a cutaway portion.