Patent
1983-08-16
1987-02-03
Abercrombie, Willie G.
17 73, A22C 2902
Patent
active
046399763
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method and system for the removal of shells from crustaceans such as shrimp and so-called krill, i.e. small crustaceans forming an immense source of protein especially in the antarctic oceans.
Conventionally, crustaceans have been peeled or shelled by mechanical pressure rollers serving to crack the shells, but as well known this type of peeling is highly inefficient and requires a considerable amount of manual afterpeeling.
Several proposals have been made for improved peeling methods and systems, but withotu practical results. Thus, according to U.S. Pat. Nos. 2,798,334 and 3,812,271, it has been proposed to peel crabs by freezing the crabs and thereafter either expose the crabs to a pressure drop at a very high vacuum, and store the crabs at a high pressure for building up a high pressure inside the crabs, whereafter the pressure is suddenly relieved for causing the shell to explode, or to store in a pressurized explosive gas mixture, which diffuses into the crab portions inside of the shell, whereafter the gas is ignited upon the pressure being relieved, whereby the shells are removed by a combustion explosion. These methods are intricate, because of the said freezing, and as with the mechanical roller method these proposals show the disadvantage that a considerable and unavoidable portion of the product as processed, that is all the crustaceans which have been only partly shelled, must be manually shelled, because a repeated treatment of partly shelled crustaceans will be practically fruitless.
Another proposal is disclosed in U.S. Pat. Nos. 4,251,902 and DE-OS 3,000,072, wherein the crustaceans are subjected to a jet of a working liquid as injected into a moving stream of crustaceans, whereby the high velocity of the liquid jet along the crustaceans, prior to these being fully accelerated, account for a sub pressure created immediately about the crustaceans for a shell loosening affect. The accelerated crustaceans are caused to pass through a pipe section having a corrugated wall, which may engage the crustaceans frictionally and thus show some peeling effect on the already loosened shell portions. However, this applies only to the outermost crustaceans in the flow, and the efficiency of the method is relatively low. Again, manual afterpeeling is necessary, because a repeated treatment of the only partially peeled crustaceans is still less efficient, and the known proposal itself is silent in this respect.
The aim of the invention resides in providing an improved method of peeling crustaceans with a generally high efficiency and simplicity, based on a pressure difference treatment and a following mechanical treatment for separating the loosened shell portions from the body portions of the crustaceans, all in such a manner that the entire process is effective not only for whole crustaceans, but even for only partly shelled crustaceans, i.e. such that it may be possible to further process the partly-shelled crustaceans simply by a repeated treatment.
According to the invention the crustaceans, in preboiled condition, are exposed to a pressure drop from a pressure level at which the body liquid adjacent the surface of the bodies and just inside the shells exists in a liquid phase, to a lower pressure level, which is low enough to cause a boiling up of the said body liquid just inside the shells, whereafter the crustaceans for the mechanical treatment are caused to be rapidly moved against or into a brake liquid serving to frictionally engage the outside of the moving crustaceans thereby peeling or drawing off the already loosened shell portions thereof.
The pressure drop boiling of the liquid just inside the shells is a very simple expedient for loosening the shells reasonably effectively, and the rapid motion of the crustaceans into the brake liquid is not only a simple expedient, but a manner of ensuring that all the crustaceans are subjected to a rather effective, yet gentle surface friction resulting in a peeling action. The two expedients together, however, accoun
REFERENCES:
patent: 4251902 (1981-02-01), Grinberg et al.
patent: 4307492 (1981-12-01), Braginsky et al.
patent: 4387485 (1983-06-01), Grinberg et al.
Hansen Otto D.
Nielsen Bent K.
LandOfFree
Method and a system for peeling crustaceans does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and a system for peeling crustaceans, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and a system for peeling crustaceans will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1084968