WO2023139442A1

WO2023139442A1 - Drum cooker

Info

Publication number: WO2023139442A1
Application number: PCT/IB2023/050143
Authority: WO
Inventors: Daniel Amman; Thomas FÄH
Original assignee: Staedler Automation Ag
Priority date: 2022-01-24
Filing date: 2023-01-09
Publication date: 2023-07-27
Also published as: CH719376A2

Abstract

The invention relates to a drum cooker for cooking bulk, floating and non-floating products, in particular food or feeds, which is also suitable for blanching or cooling. The drum cooker should allow for an output of cooked products from the drum cooker that is consistent and gentle on the product. The drum cooker (1) comprises a two-part, heatable drum, in which a conveyor screw is arranged and which has a supply chute (4) and an output unit as well as at least one output scoop (7) for the product. The conveyor screw has sections (A, B) with different inclines, a main part with spirals (6) with a constant incline (A) and a section with spirals (61) with an increased incline (B) before the product outlet.

Description

drum cooker

The invention relates to a drum cooker for cooking pourable, floating and non-floating products, in particular food or animal feed, which is also suitable for blanching or cooling.

Cookers for cooking or pre-cooking pourable, floating and non-floating products, in particular food or animal feed, have been in industrial use for decades, including drum cookers and screw cookers. They comprise a heatable metal drum or product pan or trough for receiving the product to be cooked and the cooking water. In the drum there is also a rotating screw, screw helix or conveyor screw which, when rotating, conveys the product into the cooking water, circulates it in the cooking water and at the same time moves it from the product inlet to the product outlet. The product trough is adapted to the shape of the rotary screw, screw spiral or conveyor screw. In another design, a closable, rotatable drum can also be arranged, in which a screw helix is fixed or additionally rotatable and in which the product to be cooked is circulated and conveyed when the drum rotates. Such rotary screws or worm spirals are disclosed, for example, in EP 2327317 B1, EP 2145846 B1 or EP 1255453 B1.

EP 1759586 B1 discloses a rotary screw cooker which also has two rotatable sieves in the drum in order to be able to clean them better.

The product to be cooked enters the drum via an inlet feed chute, for example according to EP 1255453 B1 or US 4688476, and after treatment is guided out of the drum by means of discharge shovels via a discharge chute, for example according to US 20190029310 A1.

The turning screws, helixes or screw conveyors have a constant pitch, as can be seen, for example, from US 20190029310 A1, US 20190098909 A1 or EP 1759586 B1. The object of the invention is to provide a drum cooker which enables the cooked products to be discharged from the drum cooker more evenly and in a manner that is gentler on the product and which makes it more effective.

The task is solved with the characterizing features of patent claim 1 .

The drum cooker according to the invention comprises a heatable, coverable cooking pan with a drum. The drum has a helix, a conveyor spiral, whose axis of rotation coincides with the longitudinal axis of the drum. The screw helix has two sections with different pitches. The pitch is constant over the main part of the screw flight from the point of product entry and, according to the invention, the pitch of the screw flights is increased before the product discharge. In previously known drum and worm cooking systems, the worm spirals have a constant gradient over the entire length of the system.

This increases the ratio of product to cooking water, which means that discharge is gentler on the product; there is less product per volume of water in the cooking water.

The invention thus enables, in comparison to the prior art, a more uniform and product-friendly discharge of the cooked products, which are more sensitive than the uncooked products, from the drum cooker, there is less product in a quantity of water volume. This is also advantageous for subsequent treatment stages of the products.

A sub-task is to provide a drum cooker that allows for a better ratio of drum diameter to product fill level in the drum. This subtask is solved with the features of patent claim 6 .

For this purpose, according to the invention, the drum cooker has a screw helix and a plurality of discharge blades, in which a separate end of the screw helix leads to each individual discharge blade. For this purpose, three additional spiral sections, each with a different length, are also preferably arranged in the last revolution in front of the discharge vanes. In previously known drum and screw cooking systems, the discharge blades have no connection to the screw spiral, with the exception of a single one, that at the discharge end of the spiral. With the exception of the discharge blade at the end of the screw flight, the other discharge blades are free-standing and have no contact or operative connection with the screw flight and discharge chute.

Thus, through the inventive interaction of worm helix and discharge blades, overcooking or undercooking of the product can be avoided by complete discharge, the drum cooker or a cooking system can process more product with the same size and the product discharge into a subsequent system is more even.

Preferred developments are disclosed in the respective dependent claims. The increased pitch of the screw helix extends over at least one screw flight and the increase is advantageously at least 30% compared to the constant pitch.

The drum is rotatable and a worm helix is arranged on the inner wall surface and/or the worm helix is rotatable within a drum cooking tub (internal cross section of the drum) adapted to the shape of the helix.

Bubbling jets are also advantageously arranged in the boiling pan in the area of the greater turning gradient. The product to be cooked is evenly distributed in the space between the spirals by water circulation.

The drum has an outer shell of perforated sheet metal so that the water flow reaches the chambers between the coils.

Without this product distribution, the product would accumulate due to the forward rotation of the screw flight.

Preferably, the discharge vanes are in the rear area, against the drum wall, a metal sheet and in the front area, against the product discharge, are sieve-like, ie perforated or provided with a slotted screen.

The bottom and rear wall of the discharge shovels are unperforated resp. closed. The drum cooker according to the invention also includes cookers which, instead of having a whole drum, only have a spiral spiral attached to a central shaft in the cooking pan.

It also includes blanching systems that correspond to the type of construction.

Furthermore, the drum cooker can also be operated with chilled water or ice water and could therefore be used as a cooling system. The same advantages are given as with the cooking variant explicitly described.

The invention is described in more detail below in an exemplary embodiment with reference to a drawing. In the drawing show the

1: a drum cooker according to the invention

FIG. 2: the drum cooker according to FIG. 1 with the drum open;

FIG. 3: the drum according to FIG. 2 in cross section;

FIG. 4: Partial view a) and b) of the product discharge area of the drum according to FIG. 2;

FIG. 5: Partial view of the drum according to FIG. 2 with discharge blades;

Fig. 6: Partial view of FIG. 5 in a different representation and

7: a discharge shovel according to the invention.

A drum cooker 1 according to the invention (FIG. 1) comprises a two-part drum 21 or a drum 21 divided along the longitudinal axis and rotatable in a fixed cooking pan 2 and a fixed cover 3, in which the drum 21 is accommodated.

It further comprises a feed chute 4 for the product to be cooked or blanched and, in the example, a discharge chute 5 for the cooked or blanched product, arranged on the drum.

A conveyor belt can also be installed as an alternative to the discharge chute. On the other hand, for products that stick a lot (e.g. cereals or legumes), a horizontal vibrating conveyor can be used instead of a discharge chute.

Such a vibration conveyor could also be designed in such a way that it has a perforated plate bottom at the beginning in order to lose as little water as possible when flushing out the discharge shovels 7 . The water could be directed back into the cooking tub 2 better through the perforated plate. The drum cooker also includes a frame assembly, not designated in any more detail, for accommodating the drum, drive elements, a controller, heating, water supply, etc

In the drum 21 a screw helix with helixes 6, 61 is arranged. The pitch of the spirals 6 (A) is constant over the main part of the screw spiral, while before the product is discharged the pitch of the last two spirals 61 (B) is increased by at least 30% in the example (FIGS. 2, 5).

The drum 21 is the rotating part of the drum cooker with the coils 6.

It is also possible to increase the incline by up to 100% compared to the constant incline.

The drum is provided with a perforated metal outer shell within the drum shell, the boiling pan 2 and the cover 3, so that the water flow reaches the chambers between the coils.

In the example, between the discharge chute 5 and the last helix 61, four discharge blades 7 are fixed in the drum 21, spaced evenly apart from one another on the circumference of the drum. The discharge shovels 7 have a screen perforation 71 (FIGS. 6, 7) in the end region facing the discharge chute 5 .

The closed areas of the discharge shovels 7 allow the product to be flushed out forward with the cooking water, the products stick less to the discharge shovels 7 and the drum wall, especially in the case of small-format products. Sticky products in particular would continue to rotate without this rinsing and continue to dwell in the system or overcooked.

Thus, the more reliable emptying of the discharge blades 7 also improves the cooking process from the product quality point of view.

Each of these four discharge blades 7 corresponds to its own screw shaft section (Fig. 5). Compared to the prior art, these are three additional helical sections, each with a different length, in the last revolution in front of the discharge blades 7 (the section with increased helical pitch, FIGS. 2 and 5).

In the area of increased pitch of the coils 61 are also bubble jets 8 for

Water arranged in the cooking tub 2, the water jets 9, respectively. a swirl in can produce the product 11 (Fig. 3, 4). The drum 21 has a perforated metal jacket, see FIG. 3, so that the cooking water gets into the drum 21 to the product.

The water turbulence or flow is so strong that it affects the product through the perforated plate.

A product 11 to be cooked is fed into the drum 21 via the feed chute 4 and cooked in the heated cooking water. The product 11 is simultaneously moved in the conveying direction 10 through the drum 21 to the discharge chute 5 as a result of the rotation of the drum and thus also of the helix.

An even distribution of the product in the chambers 12 between the spirals 6 during operation of the drum enables the product to be discharged evenly after cooking or blanching, with each discharge blade 7 discharging essentially the same amount of product.

An even product discharge per discharge shovel 7 onto the discharge chute 5 optimizes the subsequent process after the drum cooker 1, e.g. B. when the product is transferred to a cooler or to a conveyor unit.

Furthermore, an even product distribution before discharge prevents the individual discharge shovels 7 from being under or overfilled, since the size of the discharge shovels 7 can be matched to the total capacity of the cooking systems without additional reserves (per discharge shovel, so as not to overfill the last discharge shovel in front of the discharge chute 5). Product that falls back into the cooking water from an overfilled scoop is being cooked for too long, which is undesirable for reasons of product quality.

Since, for geometric reasons, it is not possible to install any desired number of discharge blades 7, the overall production output of the plant can be increased in this way.

The discharge blades 7, which skim off the product, are therefore geometrically less close to the screw helix. Pinch points between coils 6, 61 and discharge blades 7 become less narrow. Each discharge blade 7 corresponds to its own worm shaft section.

For this purpose, the coils 61 are matched geometrically and in terms of their length to one revolution of the drum. Each discharge blade 7 is charged with the same amount of product per revolution of the drum. The individual helices 61 each pick up the same amount of product in the drum zone with an increased turning pitch and direct this independently of the other helices to the respectively associated discharge shovel 7 (FIG. 7). As a result, forced emptying takes place in each respective product chamber. It is not possible to underfill or overfill the individual discharge shovels 7 and the product does not boil over.

As the drum rotates, the products are scooped out of the cooking water by the discharge shovels (Fig. 6).

With the product at least such an amount of water is carried, which helps the bottom resp. flush out the product lying behind against the drum when emptying forwards against the centrally arranged product chute 13 of the discharge chute 5 instead of sticking to the drum wall and discharge shovel 7 .

In addition, the product is discharged better from the discharge shovels 7 than with a discharge shovel that is perforated throughout.

However, the (short) screen perforation 71 or a slotted screen in the front area of the discharge shovels 7 (Fig. 7) separates the main part of the cooking water from the product that has already been swept forward, which is why as little cooking water as possible is discharged from the cooking tank 21 to the downstream system and water consumption is reduced.

In addition, part of the product chute 13 of the discharge chute 5, onto which the product is delivered, is also perforated in the example. The residual cooking water still present there returns to the cooking vat 21 in order to also prevent the discharge of cooking water to a subsequent system as far as possible.

By means of the invention, ie an increasing turning gradient and the simultaneous product distribution by water circulation, the production output of a cooking installation is increased with the same overall size, since no reserves for irregular product discharge have to be taken into account. Furthermore, due to the increased turning gradient at its discharge end and due to the product distribution described, it is possible to cook products with larger dimensions than in systems with a conventionally designed product discharge.

Reference List

1 drum cooker

2 cooking pan (lower part)

3 cover (upper part)

4 feed chute

5 discharge chute

6 spiral A

7 discharge shovel

8 nozzle

9 water jet

10 conveying direction

11 product

12 chamber

13 product chute

21 drum

61 Wendel B

71 sieve

A slope

B slope

Claims

patent claims

1 . Drum cooker for cooking pourable, floating and non-floating products, in particular food or animal feed, which comprises a heatable, coverable cooking tub (2) with a drum (21) in which a spiral spiral is arranged and which has a feed chute (4) and a discharge device as well as at least one discharge blade (7) for the product, characterized in that the spiral spiral sections (A, B) have different pitches, a main part with spirals (6) more constant from the product input point of view Pitch (A) and a section with coils (61) increased pitch (B) before the product discharge.

2. Drum cooker according to claim 1, characterized in that the discharge device is a discharge chute (5) or a vibrating conveyor.

3. Drum cooker according to claim 1 or 2, characterized in that the pitch of the spirals (61) of increased pitch is increased by at least 30% compared to the spirals (6) with a constant pitch.

4. Drum cooker according to one of claims 1 to 3, characterized in that the drum (21) and/or the screw helix is rotatably arranged, the drum (21) being adapted to the shape of the helix (6, 61).

5. drum cooker according to any one of claims 1 to 4, characterized in that in the cooking tub (2) nozzles (8) are arranged for water.

6. Drum cooker according to one of claims 1 to 5, characterized in that four discharge blades (7) are perforated like a sieve in the rear area near the product, against the drum wall as a sheet metal and in the front area against the discharge chute (5) or are designed with a slotted screen.

7. Drum cooker for cooking pourable, floating and non-floating products, in particular food or animal feed, which comprises a two-part and heatable drum in which a screw spiral and at least one discharge blade (7) are arranged and which has a feed chute (4) and a discharge device for the product, characterized in that several discharge blades (7) are arranged, with a separate end of the screw spiral leading to a discharge blade (7).

8. Drum cooker according to claim 7, characterized in that the discharge device is a discharge chute (5) or a vibrating conveyor.

9. Drum cooker according to claim 7, characterized in that four discharge blades (7) are perforated like a sieve in the rear area, against the drum wall, as sheet metal and in the front area against the discharge chute (5) or are designed with a slotted screen.

10. Drum cooker according to one of Claims 7 to 9, characterized in that the screw helix has sections (A, B) of different pitches, a main part with helices (6) of constant pitch (A) and a section with helices (61) of increased pitch (B) before the product discharge.

11. Drum cooker according to one of claims 7 to 10, characterized in that the drum and/or the screw helix is rotatably arranged, with a cooking pan (2) of the drum being adapted to the shape of the helix (6, 61).

12. Drum cooker according to one of claims 7 to 11, characterized in that in the cooking tub (2) nozzles (8) are arranged for water.