ULGENES, Yngve (Skogveien 12, Bjugn, N-7160, NO)
TOLDNES, Bendik (Henrik Mathiesens vei 55, Trondheim, N-7043, NO)
ULGENES, Yngve (Skogveien 12, Bjugn, N-7160, NO)
TOLDNES, Bendik (Henrik Mathiesens vei 55, Trondheim, N-7043, NO)
Claims
1. Device for squashing krill and other marine organisms comprising a soft protein containing material and a shell material so that some particulate and soft protein material and press-water is separated from a residue comprising shell and further protein material, characterized in that the device comprises a press band (1) and a sieve band (2) which both are endless bands which in a defined zone, hereinafter denoted the squashing zone (3/8) are arranged adjacent to one another and are arranged to move in the same direction and with a common speed, the sieve band being arranged to receive the material to be squashed upstream of the squashing zone (3/8) and is perforated with a certain, convenient mesh size and in the squashing zone is supported by a perforated plate (10) while the press band (1) in the squashing zone is supported from above by a number of pressing rolls (9) arranged mainly perpendicular to the moving direction of the press band (1), arranged to expose the material resident between the two endless bands in the squashing zone (3/8) for a controlled pressure against the perforated plate (10)
2. Device as claimed in claim 1 , characterized in that each of said pressing rolls (9) is arranged to apply an individually adapted force in the direction towards the perforated plate (10).
3. Device as claimed in any one of claims 1 or 2, characterized in that the number of pressing rolls is in the range 2-10, more preferably in the range 3-6.
4. Device according to any one of the claims 1 -3, characterized in that each pressing roll (9) in the series of pressing rolls from the inlet side (3) of the squashing zone to the outlet side (8) is arranged to apply a gradually increasing pressure compared to the preceding pressing roll.
5. Device according to any one of the preceding claims, characterized in that the supporting plate (10) or the pressing rolls (9) are arranged to temporarily and resiliently move away from the respective endless band (sieve band 2 and press band 1 respectively) if the pressure applied temporarily becomes higher than desired.
6. Device according to any one of the preceding claims, characterized in that a first propulsion roll (6) connected to a propulsion unit (motor) runs the sieve band (2) while a second propulsion roll (4) connected to a propulsion unit runs press band (1).
7. Device according to any one of the preceding claims, characterized in that the sieve band (2) is arranged in a loop that encircles the press band (1).
8. Device as claimed in claim 6, characterized in that one and the same propulsion unit is connected directly or indirectly to first propulsion roll (6) and second propulsion unit (4).
9. Device according to any one of the preceding claims, characterized in that a scraper (14) and/ or a blow nozzle (18) is arranged against the sieve band (2) downstream of the squashing zone (3/8) to scrape off or blow off remains of shell and protein material for collection and further treatment. 10. Device according to any one of the preceding claims, characterized in that a scraper (13) is arranged against the press band (1) downstream of the squashing zone (3/8) to scrape off remains of shell and protein material for collection and further treatment.
11. Device according to any one of the preceding claims, characterized in that it comprises free rotating guiding rolls (11 , 12) for the sieve band that serves the purpose of guiding the lower endless band and to hold it suitably tight during operation.
12. Device according to any one of the preceding claims, characterized in that the device comprises a collection funnel (15) or a collection plate (22) for collecting the protein containing, particulate and shell-free material and protein containing liquid which is squeezed through the perforations in the endless band. |
Device for squashing krill and other marine organisms
The present invention concerns a device for squashing krill and other marine organisms which comprises a soft protein material and a shell material so that some particulate protein material and protein containing water are separated from a residue comprising shell and further protein material.
Background
In processing krill there are typically significant amounts of shell material in the product. This yields a product which has a limited value as a fodder since flour based on whole krill contains comparatively large amounts of ashes and fluorine originating from the shell. A high content of ashes and fluorine in dried krill products has been a major contributing cause to the fact that krill not have been utilized as a resource of fodder to the desired extent. The amounts of krill in the ocean are enormous and a higher degree of utilization of these resources will in the long term relieve some of the pressure exerted on the fish stock world wide. The design of a technology and a process to obtain profitable and effective exploitation of krill as a natural resource is therefore an essential part of the development towards a higher degree of utilization of krill in general.
Earlier concepts for processing krill has e.g. made use of methods in which as much as possible of the liquid phase (glue water) is pressed out after cooking, before drying the residue fraction to a stable flour. Methods have also been used for complete or partial hydrolysis of the krill prior to separation of the shell from a hydrolysed, dissolved liquid fraction. Hydrolysis is enzymatic cleavage of the protein in the raw material (here: krill) by absorbing water. These enzymes may come from the krill itself (endogenous enzymes) or they may be fabricated enzymes added to the raw material (exogenous enzymes) in a controlled amount. There are several problems related to the above mentioned methods which limit their usefulness in a larger scale. When drying whole krill with shell a product with undesired amounts of ashes and fluorine is obtained. When hydrolysis is applied to whole krill flour of the hydrolysate will be hygroscopic. Flour as a product is considered to be perhaps the only adequate alternative in todays market of fodder production for aquaculture. Objective
It is thus an object of the present invention to provide equipment that allows optimal utilization of the raw material in marine organisms like krill in industrial scale.
It is hereunder an object to provide equipment that allows a further treatment of parts of the marine raw material in a manner not requiring hydrolysis of same, to thus allow or simplify subsequent drying of the entire organic material to a flour product.
According to the above prerequisites it is a deviated object to provide equipment that effectively and industrially is capable of separating solid or particulate protein material from a shell material in order to treat it separately from the remains of protein material following the shell fraction. The invention
Said objectives are accomplished by the device according to the present invention as defined by claim 1.
Preferred embodiments of the invention are disclosed by the dependent claims.
The krill shell is fragile and might easily be undesirably comminuted in a mechanical process so that parts of the shell material will follow the particulate fraction of the protein material (the "meat"). This is avoided by the device according to the present invention in which the krill or the marine organism comprising "meat" and shell in a short period of time is squashed between two fabrics moving with a common velocity.
The krill or the marine organism is fed from one side of the squashing device preferably in one layer onto the perforated, endless band. In what may be denoted a squashing zone parts of the meat, particularly the tail meat as well as protein containing liquid, is squeezed out of the shell. Significant amounts of the meat or protein material still remains with the shell fraction; under certain circumstances probably at least 50 % of the protein material. This, however, is not problematic since it can be recovered by enzymatic hydrolysis in a conventional manner. What is important and the aim of the present invention is to be able to provide a solid or particulate protein material which does not contain shell and therefore not requires to be treated by hydrolysis. This material is invaluable for the subsequent drying of the entire material to a flour that constitutes a fodder primarily for the aquaculture.
A significant subsequent process is required in order to turn the two fractions of the raw material leaving the device according to the present invention into a useful product, but that is not part of the present invention and therefore not described in further detail here. In connection with the present invention it is sufficient to note that the device according to the present invention allows a separation of a raw material fraction in the form of a solid, not hydrolysed, protein which can act as "carrier particles" in a subsequent drying process in which different fractions of the product again are combined.
The device is below described in further detail with reference to the enclosed drawings, where:
Fig. 1 schematically and simplified shows a first embodiment of the device according to the present invention,
Fig. 2 schematically and simplified shows a second embodiment of the device according to the present invention,
Fig. 3 schematically and simplified shows the flow of raw material into and the product flows discharged from the device according to the present invention in a preferred application.
Fig. 1 illustrated the design of the device. Two endless bands, a press band 1 and a perforated sieve band 2 are arranged vertically on top of each other. The press band 1 and the sieve band 2 travels in the same direction in the area where the bands are adjacent to one another, between 3 and 8 (hereinafter denoted the squashing zone 3/8). That means that the rolls in the pair 4 and 6 and in the pair 5 and 7, rotate with opposite directions. The rolls 4 and 6 (hereinafter also denoted second and first propulsion roll respectively) are connected to a propulsion unit and run press band 1 and sieve band 2 respectively. The rolls 5 and 7 are not attached to a propulsion unit and their rotation simply adapt to the velocity of the respective band. It is possible, though, to connect propulsion to more rolls but it is usually not convenient.
The press band 1 is typically made of a material with a certain elasticity, such as a suitable rubber or plastic (e.g. PVC) and without perforations. The press band 1 has a defined thickness, typically 2-4 mm and can be more narrow than the sieve band 2 so that it rests hard on the mid section (longitudinally) of the sieve band 2 during operation. Sieve band 2 is made of a perforated material such a sieve cloth with a defined sieve mesh and should also have a certain elasticity. The area along the longitudinal sides of the sieve band 2 can be without perforations to constitute a reinforcing element of the band, an area that need not be covered by the press band 1.
The bands pass through an area between 3 and 8 (3/8) in which they are pressed controllably together so that everything in between is exerted to such pressure. This area is denoted the squashing zone. The press band 1 is in the squashing zone pressed firmly against sieve band 2 by a series of pressing rolls 9 (a number of 7 shown in Fig. 1). The number of pressing rolls 9 can vary but it is preferred that the number is between 2 and 10 and more preferred between 3 and 7. In the squashing zone 3/8 the sieve band 2 is supported by a stationary perforated plate 10. The pressure that press band 1 exerts on sieve band 2 and further on the perforated plate 10, is controlled by the pressure from the pressing rolls against press band 1. The pressing rolls 9 can typically be adjusted up or down with adjustable screws 16 which are shown only at one of the pressing rolls 9 to reduce or increase the pressure against press band 1. The pressing rolls can as an alternative be adjustable by means of electric, hydraulic or pneumatic controlling arrangements. The pressing rolls 9 can furthermore be
suspended by a mechanical cushioning mechanism so that if e.g. a large object should enter the squashing area between pressing band 1 and sieve band 2, the pressing rolls will temporarily be pushed away and prevent that the bands 1 , 2 or the pressing rolls 9 are damaged by an excessive pressure against the perforated plate 10. The plate 10 is made in a material providing low friction to sieve band 2 such as a smooth synthetic material or a sleek metal plate.
The bands 1 and 2 can be tightened by moving horizontally the rolls 4, 5 and 6, 7 respectively, preferably by means of a set screw 17 as shown at roll 6.
In figure 1 sieve band 2 is also controlled by guiding rolls 11 and 12 in an area outside the squashing zone 3/8. These rolls need no be but can be adjustable. The guiding rolls 11 and 12 are not powered but follow the sieve band passively. The guiding rolls 11 and 12 are arranged so as to guide or centre the sieve band 2. This is accomplished by forming the guiding rolls with a tapered extension at each ends, like a reel (spool), said extensions limiting a central mid-area having a width that corresponds to the width of the sieve band 2. When the sieve band is tightened it will also be centred to this mid-area of the guiding rolls 11 , 12 where these are thinnest (have smallest diameter). Thereby the possibility of a sideways movement of the sieve band 2 on the rolls 6 and 7 will be strictly limited.
A first scraper 13 is arranged against press band 1 to ensure that material that follows the press band is scraped off at this point and falls onto the sieve band 2. Material that follows sieve band 2 out of the squashing zone 3/8 and material that falls down from press band 1 at the scraper 13 will follow the sieve band and eventually be scraped off with a second scraper 14 that rests against the sieve band. This material is generally denoted the shell fraction but contains also a significant amount of protein material (meat). At the upper side of sieve band 2 a blow nozzle 18 for blowing air through the perforated sieve band may be arranged, so that the shell fraction will fall into a collecting unit 19 arranged for continuous or periodical transfer of the shell fraction to subsequent process steps.
Solid, particulate protein material and liquid which in the squashing zone 3/8 are squeezed through sieve band 2 and the perforated plate 10, are collected in a funnel shaped receptacle 15 below the perforated plate 10. The content of the funnel shaped receptacle will be continuously or periodically transferred to subsequent process steps.
The purpose of using two bands is to be able to squeeze the krill hard between the bands in order to obtain a separation of shell from soft protein (tail meat) while the krill is completely at ease on a perforated sieve band while being squashed. Along with the soft protein all liquid will leave the krill remains.
Figure 2 shows a variant of the device of Figure 1. Contrary to the embodiment of Fig. 1 the sieve band 2 in Fig. 2 is not in its entire loop arranged below the press band 1 but encircles the press band 1. The sieve band 2 thus constitutes an outer band and the press band constitutes an inner band. This change gives rise to a number of minor changes. The device according to Fig. 2 thus comprises three rolls 7i, 7 2 , 7 3 with a function corresponding to roll 7 in Fig. 1.
In Fig. 2 the direction of movement for the press band 1 and sieve band 2 in the squashing zone is from left to right.
A particular charging device 20 is shown upstream of the squashing zone, i.e. to the left in Fig. 2 immediately above the sieve band 2 ahead of the squashing zone. The charging device can be any type of device capable of distributing the material to be squashed in a mainly even layer and desired thickness on the sieve band. The charging device may e.g. have the form of an inner perforated tube with an adequate extension, enveloped by a rotating roll or cylinder (perpendicular to the paper plane in Fig. 2) which is also provided with perforations of a size sufficient to let through the raw material used. The charging device can, however also have designs completely different from the one here described.
Straight above the charging device a transporting device 21 is shown, which for example can be a conveyor band, suitable for transporting the shell fraction that is scraped off the press band 1 out from this process to a collecting unit not shown in Fig. 2. The funnel shaped collecting receptacle 15 is in Fig. 2 substituted by a plate 22 which extends out of the squashing zone. To provide the plate the desired functionality, namely to lead the fraction that is squeezed through the sieve band 2 down to a suitable reception unit (not shown) the plate must be inclined. From practical reasons, such as space considerations, it is convenient to arrange the entire device at a certain angle v, as shown in Fig. 2. This is however, not a mandatory feature of the invention and the angle of the sieve band 2 (and the press band 1) in the squashing zone may very well be different form the angle of the plate 20. The angle of the plate should not be too small, preferably at least 20 degrees, for example 25 or 30 degrees in relation to the horizontal plane. The blow nozzle 18 in Fig. 2 has the same function as the blow nozzle in Fig. 1. While the material which is blown off the sieve band according to the embodiment of Fig. 1 goes directly to a collecting unit it is in the embodiment of Fig. 2 blown onto the press band 1 and thereafter scraped off by the scraper 13 for subsequent transportation to a collecting unit (not shown) by means of transporting device 21.
The propulsion rolls 4 and 6 are not principally different from those shown in Fig. 1. In practice typically one of the propulsion rolls, such as propulsion roll 6, will be connected to a motor while the other propulsion roll is connected to the first propulsion roll by means of
a gear wheel driving belt or the like, which ensures that the press band and the sieve band have a common linear velocity. The gear wheel drive belt may typically be provided with a tightening mechanism which allows it to be tightened independent of the tightening of the sieve band and press band. Whole krill are put on the sieve band 2 and liquid and soft protein (tail meat) are separated from the shell and pass through the perforated sieve band 2 and further down through the perforated plate 10 for subsequently being collected in a funnel shaped receptacle 15 where the shell-free, partly particulate protein is collected for further treatment. The process flows are generally indicated in Fig. 2. Fresh krill enters as flow 20. The shell fraction 21 with some protein material normally is passed to enzymatic treatment while the raw material fraction 22 is the one which is squeezed through the plate 10 and after collection is passed in as flow 23 for further treatment and drying.
The part of the krill which is not squeezed through the perforated sieve band 2 in the press device is denoted the "shell fraction". The shell fraction follows the sieve band 2 and is removed with a scraper 14 and preferably with a blow nozzle 18 and led to a collecting unit 19. This fraction will contain the residue amount of protein not squeezed out. To recover the remains of protein in the shell fraction this fraction may be treated with an enzyme in a hydrolytic process. That is not further described here.
Fig. 3 shows the flow of raw material 30 into the squashing device, a flow 31 that represents the shell fraction out from the device and a product flow 32 representing the most valuable product out from the squashing device, having the form of a liquid and a "meat" which is normally treated further (not shown).