JPH0439982B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method and apparatus for producing meals from liquid-containing or moist food ingredients, such as fish ingredients from which the liquid has been extracted in a press. Although fish raw materials are particularly emphasized here as starting materials, other raw materials, for example of animal or vegetable origin, are also readily available, especially for use as feed materials.

[Prior art and problems]

A series of different dryer systems have been proposed in the past for different types of raw materials. Both direct heat and indirect heat dryers have been used in connection with meat production from fish raw materials. The heat exchange between the heating medium (steam, flue gas, heating oil, etc.) and the raw material can be carried out directly by direct contact in the dryer or for this purpose, as for example in a direct-fired dryer. This is done by means of a heat exchange surface and, if necessary, a heat exchange surface arranged on the rotor of the dryer. Designed as food for fish, animals and humans,
A disadvantage of using open flame dryers for the production of products such as futushi meal is the contamination and absorption of toxic substances, especially from the flue gases. The disadvantages associated with indirect dryers are the long residence times required and quality changes due to the effects of prolonged high temperatures. Norwegian Patent Specification No. 99788 discloses a first dryer and a second dryer having a substantially larger capacity than the first dryer.
Discloses a method for producing fish meal by drying fish in two stages using a dryer.

OBJECTIVES The purpose of the present invention is to produce meals, for example from fish raw materials or similar animal or vegetable raw materials, in a mild but nevertheless relatively quick and efficient manner. The object of the present invention is to provide a method and apparatus. In particular, the present invention provides short drying times;
It is intended for production at moderate temperatures such that the material to be dried is exposed to a moderate heat load. This mild drying imparts flavor characteristics that make the meal attractive for certain uses. By way of example, mention may be made of marine nutrient feeds, especially for feeding fry and young fish.

[Constitution of the first invention] The method for producing meal from moist food raw material according to the present invention includes the following steps: (a) heating the raw material to a temperature of up to 450°C in order to mix the raw material with hot air; into a first drying means together with said hot air of said hot air, said hot air being added to said first drying means and whipped for up to 1 minute, thereby reducing the temperature to within the range of 190-260°C; b) Immediately thereafter, the product mixture of said raw material and said hot air is subjected to a second drying process which is relatively under the influence of a reduced pressure than the first drying means and which has a substantially larger capacity than the first drying means. (c) stirring said mixture for up to 15 minutes, whereby the temperature is further reduced to within the range 60-85°C and a meal fraction is formed; and (d) said meal removing at least a large portion of the fraction from the second drying means. The raw material and hot air remain in the first drying means for 2-50 seconds, during which time the temperature increases from 350-450℃ to 140-160℃.
℃ and remains in the second drying means for 5 to 15 minutes, during which time the temperature preferably decreases from 140 to 160C to 75 to 80C. It has been found to be particularly effective to take off from the second drying means a discharge air mixed with a portion of the meal fraction and to separate said portion of the meal fraction from this mixture. Preferably, the mixture of hot air and raw material in the first drying means is also under reduced pressure. The majority and part of the meal fraction can be transported directly to storage, but they can also be subjected to other processing, including measurement and/or testing.

【effect】

The method of the invention forms the basis for the particularly rapid drying of raw materials at moderate temperatures; the thermal energy savings of this method are good, the space occupancy is minimal and the equipment is simple. and the method has relatively great adaptability for drying raw materials of various qualities, from fresh or partially decomposed herring to old, low-quality fish. Practical tests have shown that for 24 hours, the evaporation amount is about 2500 Kg/hour with a processing capacity of 2500 hl (hector: approximately 250 tons).

[Constitution of the Second Invention] The present invention also includes the following elements: (a) first dryer means comprising an internal rotor associated with whipping means for supplying hot air and stirring the raw material; (b) ) a supply port connected at one end to said first dryer means at a location directly adjacent to said first dryer means, having a capacity substantially greater than the capacity of said first dryer means; housing an internal rotor having a plurality of peripheral blade rows of substantially radial profile disposed radially outermost side by side, with an overflow port at the opposite end for discharging the majority of the meal fraction; (c) second dryer means having a first outlet for the discharge air mixed with a portion of the meal fraction; and (c) a second outlet above the first outlet for discharge air mixed with a portion of the meal fraction; It also includes an apparatus for producing a meal from a moist food material, comprising means connected to said second outlet for separating said portion of the meal fraction. For continuous production of meal based on feed of raw material of 2500 hl (approximately 250 t) per 24 hours to produce storable meal, for example, the first dryer has an internal diameter of 1.4 m and a length of 2 m;
The second dryer may have an inner diameter of 2 m and a length of 6 m.

【effect】

The structural and mechanical solution of the invention allows large capacities to be obtained with small spaces and flexible equipment in existing factories.

【Example】

In order to understand the invention more clearly, preferred embodiments of the invention will now be described on the basis of examples and with reference to the accompanying drawings. Referring to FIG. 1, hot air assembly 10 includes a hot air source 10a. Hot air is supplied through hot air supply path 11
The hot air is supplied to the hot air supply port 12 adjacent to the raw material supply port 14 at the top of one end 13a of the first dryer 13 at a maximum temperature of 450°C. The raw material supply port 14 communicates with a supply path 15 for raw material supplied from, for example, a liquid extraction press (not shown). At the bottom of the opposite end 13b of the first dryer, a short conveying path 16 runs from the first dryer 13 to the top of one end 17a of the second dryer 17. From the other end, that is, the opposite end 17b of the second dryer 17
From there, a conveyor 19 passes through an overflow port 18 at the bottom of the dryer for discharging the bulk of the meal fraction produced in the dryer, at the tip of the arrow 20a.
leading to the discharge location as indicated by. From the other end 17b of the dryer, a discharge path 21 for a mixture of the discharged gas from the second dryer 17 and a portion of the meal fraction (i.e. a fine fraction of meal) passes through a flap 22 and a centrifugal fan 23 into a cyclone. Contact 24. A fine fraction of meal is removed from the lower end 24a of the cyclone 24 and discharged via a conveyor 25 to said discharge location as indicated by arrow tip 20b. The released gas flows from the upper end 24b of the cyclone 24 to the flow path 2.
6 to the bottom of the washing tower 27. From the top of the washing tower 27 a channel 28 leads to an inlet 29a on the heat exchanger 29, from which a channel 30 for cooled air returns to the inlet 31 of the hot air source 10a of the hot air assembly 10. A fresh air supply opening 32 having a flap 33 is connected to the flow path 30 . A branch path 34 directs air from the flow path 30 to the oil burner 3.
6 reaches the fan 35 for feeding. An oil burner 36 communicates with one side of the heat exchanger, and the other side of the oil burner 36 communicates with the air of the hot air source 10a within the hot air assembly 10. A branch path 38a leads from the oil burner 36 to the flue,
The main flow path 38b communicates with the flue via a fan 39. Figures 2 and 3 show a first dryer 1 returning from a stator 40 comprising a horizontally arranged rotor 41 with a direction of rotation as indicated by arrow 41a.
3. The stator 40 has a length of, for example, 2 m and, for example,
It has a cylindrical hollow space 42 with an inner diameter of 1.4 m. The stator 40 is constructed in four sections by three axially separated annular screens 43, 44, 45 that protrude radially inward from the circumference of the stator 40 (approximately 1/6 of the radius). 42a, 4
It is divided into 2b, 42c and 42d. The screens 43, 44, 45 are located below the bottom 40a.
each remotely controlled adjustment means 43 present in the
It has separately adjustable screen portions 43a, 44a and 45a which can be raised and lowered by means 43b, 44b and 45b. 1st by adjusting the screen
The rate of passage of the raw material/air mixture in the dryer 13 can be adjusted. An internal rotor 41, driven by a speed adjustable drive motor 46 via a drive belt 47 stretched between a drive wheel 48 and a driven wheel 49, is driven by a series of bar-like whipping means arranged within the compartment. 50. For example, the rotation speed is
170 revolutions/minute. The whipping means 50 can be configured in any desired design, but is preferably arranged so as to have a helical contour, for example each section 42a, 42b, 42c,
At 42d, two (or more) whipping means 50 are arranged in mutually opposing directions. Also, if desired, a blade may be provided at the outer end of the whipping means 50 (not shown). 4 and 5 show a cylindrical internal space 51a,
2 shows a second dryer 17 consisting of a stator 51 with a cooperating horizontally arranged rotor 52; The peripheral speed of the rotor 52 is, for example, on the order of 1 m/sec. A series of circumferential rings 55 containing directly axially extending guide blades 56 are secured to the central shaft or main shaft of the rotor 52 by struts 54 extending radially outwardly from the main shaft 53 and across. There is. Certain of the guide blades 56 extend radially inward, and the remaining blades first extend radially inward and then diagonally inward in the direction of rotation as shown by arrow 57. rotor 5
2 is driven in the direction of arrow 57 by an adjustable speed motor (not shown) coupled to the inlet end 17a of the second dryer 17. Since the circumferential ring 55 and the guide blade 56 protrude inward from the inner surface of the stator inner surface 51a beyond approximately 1/6 of the radius, the relationship between the main shaft 53, the guide blade 56, and the inner part of the circumferential ring 55 is In between, considerable flow space is made available for the mixture of raw material and hot air to be more or less freely stirred and moved in the axial as well as radial direction of the dryer. The raw material is conveyed longitudinally through the second dryer 17 primarily by the flow path of hot air passing axially through the dryer. The raw material is intermittently stirred and carried by the blades in the direction of arrow 57 and then discharged or transported from the dryer across the stream of hot air. At the outlet end 17b of the dryer 17, there is a discharge chamber 58 at the end where the blades are arranged, in which several whipping means 5 of helical profile about the main axis 53 are located.
9 is placed. By means of the whipping means 59 on the main shaft 53, a significant turbulence of the meal accumulating in the discharge chamber 58 is obtained, which ensures at least a more or less continuous removal of coarse particles in the meal; The fine particles can be collected in the air stream from the second dryer 17, as indicated by arrow 60, into the cyclone 24 via the centrifugal fan 23 (FIG. 1). First dryer 13 by centrifugal fan 23
and a certain pressure drop in the second dryer 17 can be guaranteed. The centrifugal fan 23 simultaneously runs from the inlet end of the first dryer 13 to the outlet end of the dryer.
and also provides a defined throughflow of air to the outside of the second dryer 17. In fact, only the fine particles of the meal fraction are drawn in with the air stream. At the outlet, a second
It is primarily fine particles that are conveyed from the dryer 17 in a substantially vertically upward direction. Coarse meal particles are transferred from the discharge chamber 58 of the second dryer 17 to the overflow port 1.
The particles are removed in bulk form using whipping means 59 which force the particles outwardly through 8 . Due to the first dryer 13 generated by the centrifugal fan 23 and the raw material sent to this first dryer 13 and the hot air sent from the hot air assembly, and because of its larger capacity than this first dryer 13, this first dryer 13 is relatively The second dryer is under further reduced pressure than the first dryer.
The reduced pressure state in the dryer 17 and the whipping means 5
0. Rapid and effective drying of the substance by combining the turbulence effect and the agitation effect which the substance is subjected to by the whipping means 59 in the first dryer 13, the guide blade 56 and the second dryer 17. is guaranteed. By being carried with the air flow into and out of the dryer, the fine particles are removed by the air flow in a completely dry state.
While some of the coarse particles will necessarily be removed by the air flow, some will remain in the dryer until the moisture content is sufficiently reduced by the whipping and turbulence of the air. As a result of the average particles being trapped in the air stream, the first dryer 13,
easy to move axially through the second dryer 17;
As a result, during whipping and rotation in the first dryer 13 and the second dryer 17, good contact with the air flow can be achieved. By adjusting the screen sections 42a-42c perpendicularly to the bottom of the first dryer 13, the air flow through the first dryer 13 can be adjusted as required. Accordingly, the rotor 4 in the first dryer 13 and the second dryer 17
By adjusting the rotation speed of 1.52, the combined effect of air flow, whipping of the material and rotation in the dryer can be further influenced.

[Brief explanation of drawings]

Figure 1 is a schematic flow diagram of an apparatus for producing meal from moist plant material, and Figures 2 and 3 are front and side sectional views of the first dryer of the apparatus of Figure 1. Yes, Figures 4 and 5 are
2 is a schematic front view and a side view of a second dryer of the apparatus of FIG. 1, and the side view is a sectional view. FIG. 10... Hot air assembly, 10a... Hot air generation source, 13... First dryer, 17... Second dryer,
18... Overflow port, 19... Conveyor, 21...
Discharge path, 22... flap, 23... centrifugal fan, 24... cyclone.

Claims (1)

Claims: 1. The first stage is carried out in a first dryer and immediately thereafter in a second dryer having a substantially larger capacity than the first dryer relative to the first dryer. In a process for the production of meal from a liquid-containing or moist food raw material, such as a fish raw material from which the liquid has been extracted in a press, consisting of a two-stage process in which the second stage is carried out under the influence of reduced pressure, the following steps are taken: - supplying the raw material to the first dryer 13 together with hot air having a temperature of up to 450°C to mix the raw material and the hot air; - into the raw material in the first dryer 13; Whip the hot air for less than 1 minute to 190~260℃
- Transfer the mixture obtained from the raw material and the hot air to the second dryer 17; - Stir the mixture for less than about 15 minutes to reduce the temperature to 60-85
further reducing the temperature in the range of 0.degree. C. to form a meal fraction; and removing at least a major portion of the meal fraction from the second dryer 17. 2. Process according to claim 1, characterized in that a part of the meal fraction is removed together with the discharge air and then said part is separated from the discharge air. 3. The method according to claim 1 or 2, characterized in that the mixture of hot air and raw material in the first dryer 13 is placed under reduced pressure. 4 Add hot air to the raw material in the first dryer 13 and whip for 2 to 50 seconds, during which time the temperature will rise to 350 to 400.
The method according to claim 1, 2 or 3, characterized in that the temperature is lowered from 140 to 160°C. 5 The mixture in the second dryer 17 is stirred for 5 to 15 minutes, during which time the temperature decreases from 140 to 160°C to 75 to 80°C.
3. The method according to any one of Section 2, Section 2, Section 3, or Section 4. 6 from a liquid-containing or moist food material, such as a fish material fed from a liquid extraction press, comprising a first dryer and a second dryer having a substantially larger capacity than the first dryer; In the apparatus for producing meal, a first dryer 13 comprises an internal rotor with whipping means for whipping hot air into said raw material, and a second dryer 17 comprises a first
a plurality of blade rows having a substantially radial profile arranged axially and radially outermost, having a supply port directly adjacent to the dryer 13 and communicating with the first dryer at one end; and a first outlet 18 and the meal fraction above the first outlet as an overflow port for the second dryer 17 to discharge the majority of the meal fraction at the opposite end. A device characterized in that it has a second outlet 21 for the discharge air mixed with a part of the meal fraction and a device 23, 24 for separating the part of the meal fraction from the discharge air. 7. Device according to claim 6, characterized in that the separation device comprises a cyclone (24) connected to the second outlet (21) via a central fan (23).