NO342292B1 - stirrer - Google Patents

Abstract

Agitator (200) joins mixing tank (102) for fluids, in particular a hydrolysis tank (102) for enzymatic hydrolysis of proteins. The agitator comprises a shaft (202), a number of agitator vanes (203a, 203b, 203b) in the form of vertically projecting flat struts (208, 209) connected to the shaft (202) in a frame (207). A number of elongate baffles (205a ', 205a ", 205a'") are attached with their short side ends to the struts (208, 209) with a mutual distance in the vertical direction at respective heights (Ha ', Ha ", Ha'") from the bottom of the agitator (200). Each baffle plate (205a ', 205a ", 205a'") is rotated out of the horizontal plane at a given angle (ya) about an axis projecting radially on the longitudinal axis of the shaft (202). In a subsequent corresponding stirring wing (203b) the height (Hb ', Hb ", Hb'") is lower than the corresponding heights in the first stirring wing (203a) and the angle (ab) of the baffles (205b ', 205b ", 205b'" ) in the subsequent stirring wing (203b) has the opposite sign than the first angle (åa). During agitation, the baffles will set significant parts of the bulk phase in the tank in motion and cause agitation.

Description

The present invention relates to an agitator for a hydrolysis tank for enzymatic hydrolysis of proteins, as appears from the introductory part of patent claim 1.

Background

The starting point for the invention is related to the processing of organic raw material from fish, birds and land-based animals for the production of refined fat and oil, proteins and collagen for use in cosmetics or foodstuffs. Such organic raw material can be by-products from the poultry industry, by-products from the meat industry or by-products from the fishing industry.

One example of such a process is described in NO 320736 B1 by the same inventor as the present one. As other examples from the known technique, WO 2004071202 and WO 2004006845 can be mentioned. This process includes a step of enzymatic hydrolysis of proteins in a water solution in a hydrolysis tank. Such a hydrolysis tank for enzymatic hydrolysis of a water solution of the organic raw materials is described in NO 321014 B1 by the same inventor as the present one.

A disadvantage of the known technique, however, is that the processes can lead to deterioration of the protein products by a bitter taste arising from the shortening of the amino acid ends in the proteins due to a long processing time. To avoid this, the residence time in the hydrolysis tank has had to be reduced. As a result, raw material utilization and production capacity are limited compared to what would have been desirable.

WO 2010/139470 describes an agitator in the form of a combination of an axially directed guide element and at least one radially directed inclined guide element about a rotation axis.

EP 3012320 describes a fermentation device with a stirrer consisting of an outer framework with longitudinal vertical and transverse horizontally projecting stiffeners.

CH 334213 describes a device for producing flowable masses where a main agitator is provided with an additional agitator arranged inside the main agitator. A drive unit assigns a relative movement to the main agitator in a first direction of rotation, while the main agitator in the second direction of rotation is assigned zero relative movement in relation to the additional agitator.

JPH 01168271 describes a tank with two agitators placed above each other on a common shaft to prevent fouling.

WO 2006/096067 describes a method for an enzymatic hydrolysis process of collagen and proteinaceous raw materials, as well as a hydrolysis tank with a rotatable stirring mechanism consisting of a guide plate with a bottom scraper placed at the distal end, which is rotated vertically about the central axis.

Purpose

One purpose of the invention is therefore to provide an agitator in such a hydrolysis tank which provides a shorter processing time for enzymatic hydrolysis of proteins. Another purpose of the invention is to provide such a mixer where high quality proteins can be produced without a bitter taste.

The invention

These purposes are achieved with an agitator according to the characterizing part of patent claim 1. Further advantageous features appear from the independent patent claims.

The invention solves these objects with a new agitator which is arranged to be mounted in a hydrolysis tank in a processing plant for processing organic raw materials from fish, birds and land-based animals for the production of oil, proteins and collagen. The new agitator is arranged to rotate inside the hydrolysis tank and create a more efficient agitation than has been achieved up to now, and as a result offer enzymatic hydrolysis of a given volume of organic raw material in a shorter period of time and without the formation of bitter taste on proteins and without reduced raw material utilization.

While the agitator is particularly related to use in a hydrolysis tank for enzymatic hydrolysis of proteins, the invention is not limited to this. The mixer's efficient mixing function can also be utilized in other processes where efficient mixing is sought.

Definitions

The term "axle" refers to the agitator's connecting point between the propellant and the agitator blade. The shaft may be an axially directed shaft projecting down from a drive mechanism at the top of the tank down towards the bottom of the tank and is arranged to rotate about a substantially vertically projecting longitudinal axis. The shaft can extend all the way down to the bottom or only a short distance into the tank, whereby the stirring blades are attached to a framework. Alternatively, the connecting point between the drive and stirring blade can be another type of construction, for example a housing or a ring connected to the drive.

"Longitudinal axis" means the longitudinal axis of the axle when it is mounted in the tank. This designation is also used to denote the agitator's axis of rotation when mounted in the tank.

By "guide blade" here is meant means which ensure that the bulk phase in the tank is set in motion during rotation of the agitator.

The term "stirring vane" means a separate part of the stirring system arranged at a distance radially from the longitudinal axis of the shaft. The stirring vane serves primarily as a fastening device for the guide plates, but can also serve as a stirring blade or guide blade itself.

The term "following stirring vane" here means a given stirring vane arranged after another stirring vane seen in the direction of rotation of the agitator.

Summary

The invention relates to an agitator for a mixing tank for fluids, in particular a hydrolysis tank for enzymatic hydrolysis of proteins, in which the agitator is arranged to be mounted rotatably inside the tank with a cylindrical wall, in which the agitator comprises a mainly vertically projecting shaft connected to a drive mechanism. The shaft is provided with agitator vanes arranged at a distance radially from the axis of rotation of the agitator towards the wall of the tank. According to the invention, the agitator has at least one first agitator vane and a second agitator vane arranged at an angle to each other, in a successive position seen in the direction of rotation of the agitator.

The first stirring vane is provided with at least one first guide plate located at a first height Ha', and a second guide plate located at a second height Ha'' which is lower than the first height Ha' so as to form a space between the guide plates available for flow of fluid in the tank, in which the guide plates are twisted about an axis projecting towards the longitudinal axis of the shaft at an angle αamed the horizontal plane which is different from zero.

The second stirring vane is provided with at least one first guide plate located at a first height Hb', and a second guide plate located at a second height Hb'' which is lower than the first height Hb' so as to form a space between the guide plates available for flow of fluid in the tank, in which the guide plates are twisted about an axis projecting towards the longitudinal axis of the shaft at an angle αb with the horizontal plane which is different from zero.

The angle αa has the opposite sign to the angle αb, so that the surface on the upper side of the guide plates in the first stirring vane contacts the fluid in the tank during rotation of the agitator, and the surface on the underside of the guide plates in the second stirring vane contacts the fluid during rotation of the agitator, or vice versa, and the heights Ha', Ha'' for the guide plates in the first stirrer wing are different from the heights Hb', Hb'' for the guide plates in the second stirrer wing.

In a preferred embodiment, the agitator has at least a third consecutive agitator vane provided with at least a first guide plate arranged at a first height Hc' and a second guide plate arranged at a second height Hc'', in which the heights Hc', Hc'' for the guide plates in the third stirring vane are different from the respective heights Hb', Hb'' of the respective guide plates in the second stirring vane.

The pipe vanes are preferably arranged at an angle to each other about the shaft which are essentially identical.

Each stirring vane can further be provided with at least a third guide plate arranged at a third height Hc''' which is lower than the height Ha'', Hb'', Hc'' of the second guide plate.

A scraper blade may advantageously be arranged at the lower end of each agitator vane, arranged to be guided along the bottom of the tank during rotation of the agitator.

The respective heights of the guide plates in a given stirring vane are in one embodiment higher than the respective heights of the guide plates in a subsequent stirring vane.

The guide plates' inclination angle αa; αb; In one embodiment, the αcmed horizontal plane has alternating signs in successive stirrups.

In one embodiment, the absolute value of the angle of inclination is identical for all guide plates.

Each agitator vane may further comprise a first substantially vertically projecting rod located at the periphery of the agitator, and a second substantially vertically projecting rod arranged at a distance from the first rod in a direction radially inward towards the axis of rotation of the agitator, in which the guide plates are attached with their respective ends to the first and second stage.

In a preferred embodiment, the rods are shaped as a band-shaped rail with a flat end projecting mainly radially towards the agitator's axis of rotation. This design adds further mixing effect to the mixer.

The guide plates can be arranged manually or mechanized pivotable to the stirrer vane to adapt the tilt angle or tilt angles to the consistency of the bulk phase and to the specific arrangement of stirrer vanes and guide plates.

The guide plates' respective inclination angle α can be essentially identical or mutually different. In one embodiment, the inclination angle α of the guide plates is approximately 45°.

Detailed description

The invention is subsequently described in more detail with reference to figures, where the same or similar reference numbers are used for the same or similar components:

Fig. 1 is a simplified flow chart of a process for the production of organic oil, collagen and protein-containing material from organic material,

Fig. 2 illustrates a hydrolysis tank for enzymatic hydrolysis of the organic material seen from the side,

Fig.3 illustrates a stirrer according to the invention seen from the side,

Fig.4 illustrates the agitator in figure 3 seen in perspective from above,

Fig. 5a-c illustrate details of parts of the mixer in figures 3 and 4 split into separate parts seen from the side, and

Fig.6 is an end sketch of the details in figure 5a-c.

Now with reference to Figure 1, a simplified flow chart of a process for the production of pure fractions of fat and oil, water-soluble proteins and insoluble proteins by enzymatic hydrolysis of organic raw material from fish, birds and land-based animals is illustrated. The process generally indicated by reference number 100 where raw material indicated by 101 is supplied to one or more hydrolysis tanks 102a, 102b, each of which is provided with heating means, agitators and transport screws. An example of such a hydrolysis tank can be obtained from the above-mentioned patent publication NO 321014 B1. The hydrolysis tank is supplied with water and enzymes (not illustrated) together with the organic raw material, after which the contents are heated for a period of time while stirring and cause hydrolysis of the organic raw material. Fat and oil are collected in a top layer and removed in line 104a, 104b and further via collection line 104 to an oil separator 105. A middle layer of water-soluble proteins is removed from hydrolysis tank 102a, 102b and passed on to a filter 103 for the removal of rejects in the form of solid particles. The filtered liquid with water-soluble proteins is then passed on to a hydrolyzate separator 108 and on to a clarification tank 109a, 109b where collagen is taken out as a solid fraction (not illustrated) and the protein solution is passed on via buffer tank 110a, 110b to an evaporator 111 for the enrichment of proteins . Water-insoluble proteins, bone remains and the like are removed from the bottom of hydrolysis tank 102a, 102b with the help of a screw. A more detailed description of this process can be obtained from the above-mentioned patent publication NO 320736 B1.

An example of such a hydrolysis tank 102 is shown in Figure 2 with a motor 201 placed on top of the tank 102 to drive an agitator described in more detail below.

Figure 3 shows an agitator 200 according to the present invention. A vertically projecting shaft 202 is connected to a drive motor (201 in Figure 2), arranged to rotate the agitator 200 about the shaft 202. Three agitator wings 203a, 203b, 203c each comprise a substantially vertically projecting first strut 208 arranged in the periphery of the agitator 200 and a second substantially vertically projecting second strut 209 arranged at a distance towards the longitudinal axis of the shaft 202. The rods preferably have a surface which projects radially in towards the longitudinal axis of the shaft 202, so as to contribute to the stirring of the bulk phase in the tank. Each stirring vane is firmly connected to the shaft 202 by means of a framework 204a, 204b, 204c, 207.

Each stirring vane 203 is further provided with three guide plates 205a', 205a'', 205a'''; 205b', 205b'', 205b'''; 205c', 205c'', 205c''' for the respective stirring vane 203a, 203b and 203c. The guide plates are preferably elongated with long side ends attached to the first strut 208 and second strut 209 respectively.

The first (top) 205a' of the three guide plates in the first stirring vane 203a is attached to the stirring vane at a first height Ha'. The second (middle) guide plate 205a'' in the first stirrer wing 203a is fixed at a second height Ha'' lower than the first height Ha' and leaves a space between the first 205' and second 205'' guide plate through which liquid can flow. The third (lower) 205''' guide plate is fixed at a third height Ha''' lower than the second height Ha'' leaving a space between the second 205'' and third 205''' guide plate through which liquid can flow. Attached to the lower end of each stirring vane 203a, 203b, 203c is a scraper blade 206a, 206b and 206c, respectively, which is arranged to scrape along the bottom of the hydrolysis tank. The third guide plate 205a''' fixed at the height Ha''' is located above the scraper blade 206a and correspondingly forms a space in between where water can flow through.

In a similar way as for the first stirring vane 203a, the respective guide plates 205b', 205b'' and 205b''' in the second stirring vane 203b are mounted at respective heights Hb', Hb'' and Hb''' which are different (higher) than the respective heights Ha', Ha'' and Ha''' in the first stirring vane 203a.

In a similar way as for the first and second stirring vanes 203a and 203b, the respective guide plates 205c', 205c'' and 205c''' in the third stirring vane 203c are mounted at respective heights Hc', Hc'' and Hc'' which are different (higher) from the respective heights Hb', Hb'' and Hb''' in the other.

This height arrangement of the guide plates 205 in the respective stirrer wings 203 can be seen in particular from figures 5a, 5b and 5c.

Furthermore, the guide plates 205a', 205a'' and 205a''' in the first stirring vane 203a are twisted at a first angle αamed the horizontal plane about an axis extending mainly radially with respect to the axis of rotation of the shaft 202, so that the guide plates 205 during rotation of the agitator 200 define a inclined surface. The liquid in the tank will thus meet the surface of the guide plate 205 in a direction of flow oblique to the surface of the guide plate 205. This surface of the guide plate 205 can be the underside or the upper side of the guide plate 205, depending on which way the guide plate 205 is twisted with respect to the direction of rotation of the agitator 200 about the shaft 202.

The size of the angle α can vary depending on various factors, such as the calculated rotation speed of the mixer, the number of mixer blades and the distance between them. Examples of angle sizes are 10-80°, such as 30-60°, especially mainly 45°.

The guide plates 205b', 205b'' and 205b'' in the second stirring vane 203b are, in a similar way as described for the first stirring vane 203a, twisted at a second angle αb with the horizontal plane, and the guide plates 205c', 205c'' and 205c'' ' in the third stirring vane 203c is twisted at a third angle αcm with the horizontal plane.

The angles αa,αb andαchar in the illustrated embodiment are essentially the same size with respect to the horizontal plane, but in a preferred embodiment have alternating signs so that the liquid in the hydrolysis tank 200 will hit the underside of the guide plates in one stirrer vane and the upper side of the guide plates in the following stirrer vane seen in the direction of rotation of the agitator 200.

The arrangement with guide plates 205 arranged at different heights between respective stirring vanes and preferably in alternating inclination angles between successive stirring vanes, provides for setting up a particularly effective mixing effect where significant parts or mainly all parts of the bulk phase are set in motion.

As a result of this, the hydrolysis process can be carried out in a shorter time so that the shortening of the ends of the amino acids is avoided and consequently the formation of a bitter taste on the collagen is avoided. The agitator offers efficient mixing and leaves no shadow sides or pockets in the bulk phase being stirred.

In other words, the mixing plant according to the invention offers faster processing of the organic raw material and provides end products of higher quality without compromising efficiency (raw material utilization) or capacity.

Modifications

The number of stirrer vanes can be different from three, for example 2 or 4. The guide plates do not need to be fixed in a fixed position to the stirrer vane and can be provided with drive means that can batchwise or continuously change the plate's twist angle, alone or synchronously with the remaining guide plates. Each stirring vane is illustrated with three baffles, but the invention is not limited to this, and the number of baffles per stirring vane can be, for example, two or four. Furthermore, the distance between the guide plates in a stirring vane can be mutually different. While the guide plates are illustrated as mainly elongated guide plates attached with their long side ends to the stirrup vane, the guide plates can also be square or be attached with their short side ends to the stirrup vane.

Claims (14)

Patent claims 1. Agitator (200) for a hydrolysis tank (102) for enzymatic hydrolysis of proteins, wherein the agitator (200) is arranged to be rotatably mounted inside the tank (102) with a cylindrical wall, wherein the agitator comprises a substantially vertically projecting shaft (202) connected to a drive mechanism (201), which shaft is provided with stirring vanes (203) arranged at a distance radially from the axis of rotation of the stirring mechanism (200) towards the wall of the tank (102), characterized in that the stirring mechanism has at least one first stirring vane (203a ) and a second stirring vane (203b) arranged at an angle to each other, in a subsequent position seen in the direction of rotation of the stirring unit (200), in which the first stirring vane (203a) is provided with at least one first guide plate (205a') located at a first height (Ha'), and a second guide plate (205a'') located at a second height (Ha'') which is lower than the first height (Ha') so as to form a space between the guide plates (205a', 205a'') available for the flow of fluid in the tank (102), in which the guide plates (205a', 205a'') are twisted about an axis projecting towards the longitudinal axis of the shaft (202) at an angle (αa) with the horizontal plane which is different from zero, the second stirring vane (203b) is provided with at least one first guide plate (205b') located at a first height (Hb'), and a second guide plate (205b'') located at a second height (Hb'') which is lower than the first height (Hb') so as to form a space between the guide plates (205b', 205b'') available for the flow of fluid in the tank (102), in which the guide plates (205b', 205b'') are twisted about an axis projecting towards the longitudinal axis of the shaft (202) at an angle (αb) with the horizontal plane which is different from zero, wherein the angle (αa) has the opposite sign to the angle (αb), so that the surface on the upper side of the guide plates (205a', 205a'') in the first stirrer wing (203a) contacts the fluid in the tank during rotation of the stirrer (200), and the surface on the underside of the guide plates (205b', 205b'') in the second stirrer wing (203b) contacts the fluid during rotation of the stirrer (200), or vice versa, and that the heights (Ha', Ha'') of the guide plates in the first stirring vane (203a) are different from the heights (Hb', Hb'') of the guide plates in the second stirring vane (203b). 2. Agitator according to claim 1, characterized in that the agitator exhibits at least a third consecutive agitator vane (203c) provided with at least a first guide plate (205c') arranged at a first height (Hc') and a second guide plate (205c') ') arranged at a second height (Hc''), in which the heights (Hc', Hc'') of the guide plates in the third pipe wing (203c) are different from the respective heights (Hb', Hb'') of the respective guide plates in the second stirrup wing (203b). 3. Agitator according to claim 2, characterized in that the agitator wings (203a, 203b, 203c) are arranged at a mutual angle about the shaft (202) which are essentially identical. 4. Agitator according to one of the preceding claims, characterized in that each agitator vane is provided with at least a third guide plate (205a''', 205b''', 205c''') arranged at a third height (Hc'') which is lower than the height (Ha'', Hb'', Hc'') of the second guide plate (205a'', 205b'', 205c''). 5. Agitator according to one of the preceding claims, characterized in that a scraper blade (206a, 206b, 206c) is arranged at the lower end of each agitator vane (203a, 203b, 203c), arranged to be guided along the bottom of the tank (102) under rotation of the agitator (200). 6. Agitator according to one of the preceding claims, characterized in that the respective heights of the guide plates in a given agitator vane are higher than the respective heights of the guide plates in a subsequent agitator vane. 7. Agitator according to one of the preceding claims, characterized in that the guide plates' angle of inclination (αa; αb; αc) with the horizontal plane has alternating signs in successive impeller vanes (203a; 203b; 203c). 8. Agitator according to one of the preceding claims, characterized in that the absolute value of the angle of inclination is identical for all guide plates. 9. Agitator according to one of the preceding claims, characterized in that each agitator wing (203) comprises a first mainly vertically projecting stay (208) located at the periphery of the agitator (200), and a second mainly vertically projecting stay (209) arranged at a distance from the first rod (209) in the direction radially towards the axis of rotation of the agitator (200), and that the guide plates (205) are attached with their respective ends to the first and second rods (208, 209). 10. Agitator according to claim 9, characterized in that the rods (208, 209) are shaped like a band-shaped rail with a flat end projecting mainly radially towards the axis of rotation of the agitator (200). 11. Agitator according to one of the preceding claims, characterized in that the guide plates (205) are arranged manually or mechanically pivotable to the agitator vane (203). 12. Agitator according to one of the preceding claims, characterized in that the guide plates (205)'s respective angle of inclination (α) are essentially identical. 13. Agitator according to one of the preceding claims, characterized in that the respective inclination angle (α) of the guide plates (205) are mutually different. 14. Agitator according to one of claims 1 to 12, characterized in that the guide plates (205) inclination angle (α) is approximately 45°.