Apparatus and method for producing wort.

Abstract

The invention relates to an impact mill (1) with water injectors (8, 9), in particular for grinding green malt. The impact elements can be hammers (6) and / or knives (7). The invention also relates to a method for producing wort from green malt or any other germinated cereal by simultaneous grinding and mashing.

Description

[Technical Field]

[0001] The present invention relates to a method for producing wort, in particular from green malt or any other germinated grain. The present invention also relates to an apparatus for grinding, in particular green malt or any other germinated grain. [Background technology]

[0002] The production of wort is a necessary step in several industries, particularly in brewing, distilling or other industries related to the production of extracts, beverages or foods made from grains.

[0003] (Introduction) The process for producing wort typically includes the following steps: Starch-containing raw materials are pre-milled and / or mixed with water. The resulting suspension, known as the "mash," is obtained through the milling and mashing process. The mash is then heated to various temperatures, allowing enzymes to convert the starch into sugars. This is the brewing process. At the end of the brewing process, the mash is filtered to separate the insoluble material (spent grain) from the wort. This is typically done using a lauter tun or a filter press. To use a membrane filter press manufactured by the applicant or equivalent technology, the raw materials must be finely milled. In this case, the milling process aims to obtain a particle size distribution centered between 125 μm and 1 mm, with at least 60% of the particles preferably falling within this size range. The wort is then processed according to the end product to be produced. During the brewing process, the filtered wort is subjected to a boiling process. Hops are added to the wort at this stage, and it is then clarified before being cooled and transferred to fermentation. This process can be carried out batchwise, continuously, or semi-continuously.

[0004] The raw materials used in wort production vary, including grains or pseudo-grains, ungerminated or germinated. When producing beer, recipes typically include "malt." Malt is a grain (usually barley) that has undergone steeping, germination, roasting, and germination prevention processes. The term "malt" is used broadly herein to refer to "germinated grain." Thus, while the term "malt" refers to barley, it also includes other grains, such as wheat, rye, oats, and sorghum. Steeping is a preparatory step for germination, hydrating the grain to increase its moisture content to approximately 45%. Germination then begins. This stage lasts for 3 to 5 days, during which malt enzymes are produced. Once germination is complete, the enzymatic activity of the malt, known as "green malt," reaches its maximum. Green malt's high moisture content makes it microbiologically unstable and impossible to store or transport. Roasting is a drying process that converts "green malt," which has a moisture content of about 40-50%, into malt with a moisture content of about 4%. During roasting, many enzyme activities are stopped, reducing the enzymatic activity of the malt.

[0005] There is growing interest in producing wort from "green malt" or other germinated grains with limited or no roasting.

[0006] The advantage of using green malt is, on the one hand, reducing the energy consumption of the production process by completely or partially eliminating the kiln drying step, and, on the other hand, optimizing the wort production process by making maximum use of the enzymatic power of the raw material (reducing the time required to convert starch into sugars during the brewing process).

[0007] However, there are several problems with using this raw material. - Green malt is not microbiologically stable and cannot be stored for more than a few days. For this reason, green malt must be introduced into the process immediately after germination. - Green malt has a high moisture content and root sprouts are present from the time of germination, which makes the upstream brewing process, especially the milling process, very complicated. In fact, with a moisture content of 40-50%, the root sprouts and outer skin become brittle and even elastic, making it difficult to mill using conventional techniques.

[0008] The use of green malt has been described since the beginning of the 20th century. British Patent No. 190914266 describes a method for preparing malt extract. The green malt is ground using a millstone.

[0009] French Patent No. 356024 describes a basic mill for grinding green malt. This mill uses a rotary cutter attached to a rotor and positioned against a perforated plate. Knives scrape the perforated plate. This is not an impact mill.

[0010] However, these very old techniques did not allow for industrial production of beer by these methods.

[0011] WO 03 / 048294 describes a method for stabilizing green malt for the brewing industry, which allows preservation of the green malt while reducing the energy consumption of the kiln. The grinding process is carried out using a disc mill.

[0012] WO 2021 / 099867 describes a method and apparatus for optimizing the use of green malt in the brewing process. The apparatus includes a first stage in which the grain is chopped before being crushed, and a second stage in which the crushed green malt is then crushed between two stones. The two-stage continuous process is complex and requires additional equipment, which increases the cost of wort production.

[0013] French patent No. 3042721 describes a grain mill for animal feed. The mill has rectangular striking elements Cx rotatably mounted on a shaft. This mill is not suitable for grinding green malt. The mill operates in a dry process.

[0014] European Patent No. 0845528 in the name of the present applicant describes a grinding method for obtaining a finely ground product. This method uses a disc mill underwater. However, in the case of green malt, this type of grinding has capacity and efficiency problems. Because the high moisture content of the husk of green malt makes it "elastic," it has proven more difficult to grind than malt or other germinated materials. This capacity limitation precludes its use in industrial breweries, resulting in prohibitively high investment and operating costs. Because disc mills operate based on the principle of friction, achieving a sufficiently small particle size is difficult, especially when meeting the prerequisites for optimal operation of membrane filter presses. Summary of the Invention

[0015] One object of the present invention is to produce wort from green malt or any germinated grain with a moisture content greater than 15%, preferably greater than 20%, thereby eliminating the energy-intensive kiln drying step and taking advantage of the high enzymatic activity of green malt.

[0016] In particular, it is an object of the present invention to ameliorate the problems encountered when milling green malt.

[0017] Another object of the present invention is to provide a grinder suitable for grinding green malt.

[0018] It is also an object of the present invention to produce beer produced from the fermentation of wort obtained from green malt.

[0019] The applicant has commercialized a hammer mill type impact crusher for producing finely ground material from ungerminated or germinated grains having a moisture content of 3 to 15%.

[0020] This type of mill consists of a grinding chamber with an inlet and an outlet for the material, and one or more rotors, preferably with a horizontal axis, on which disks supporting hammers are mounted. The rotors operate at a rotational speed that imparts a high peripheral velocity to the hammers, preferably on the order of 100 m / s. A sieve, i.e., a perforated plate, is located at the bottom of the grinding chamber. The size of the sieve holes is selected depending on the target particle size and the grindability of the raw materials. For malt grinding, sieves with holes ranging from 1.5 mm to 4 mm in diameter can be used, depending on the size of the mill.

[0021] The grinding chamber is connected to a forced ventilation unit.

[0022] This type of mill has never been used for green malt. The maximum moisture content of the grain to be milled is 15%. Above this moisture level, problems with clogging of the screens occur.

[0023] The present invention therefore relates to an impact mill, in particular for grinding green malt, comprising: - a casing surrounding the grinding chamber; - at least one rotor; an impact element driven in rotation by said rotor, The casing has an inlet for the raw material and an outlet for the ground material, the casing being equipped with an injector for water.

[0024] In particular, the grinding chamber comprises a sieve.

[0025] When the rotor is in a horizontal position, the sieve can advantageously be arranged in the lower part of the grinding chamber.

[0026] In particular, at least one injector is positioned so that water is fed directly into the grinding chamber (without passing through a sieve). In the case of horizontal-shaft mills, this injector is positioned at the top of the grinding chamber. If the mill has a horizontal shaft, the other injector is positioned to feed water behind the sieve, i.e., at the bottom of the grinding chamber.

[0027] Some of the impact elements may be hammers, while others may be ground into the shape of knives.

[0028] Advantageously, the impact element is pivotally mounted on a shaft that is rotated by the rotor. The crusher can accommodate a number of shafts, preferably 4 to 8 shafts, and more preferably 4 shafts.

[0029] The hammers and knives can be arranged on the same axis, for example the first and last impact elements are knives and the other impact elements are hammers. Any other arrangement is also possible, for example the knives and hammers can be arranged alternately or the majority can be knives.

[0030] The shaft carrying the knife is driven by the rotor by means of a support part which may be a disk, although any other shape may be considered.

[0031] Spacer elements may also be disposed between each impact element.

[0032] Advantageously, the sieve has holes between 1.0 mm and 4.0 mm, preferably between 2 mm and 3 mm.

[0033] The invention also relates to the use of the grinder described above, in particular for grinding green malt or any other germinated cereal grain having a moisture content greater than 15%, preferably greater than 20%, or even between 40 and 50%.

[0034] The invention also relates to a method for producing wort, characterized in that green malt or any other germinated grain is fed to an impact mill and subjected to simultaneous grinding and mashing processes.

[0035] Advantageously, the method according to the invention uses a grinder as described above.

[0036] In particular, the mashing water is introduced through an injector, with the total amount of mashing water being 0.5 to 3.0 liters / kg, preferably 1 to 2.0 liters / kg, in terms of (water / green malt) ratio.

[0037] Preferably, a portion of the mashing water is introduced through an injector located at the top of the mill, and another portion of the mashing water is introduced through an injector located at the bottom of the mill.

[0038] Advantageously, the duration of the grinding / mashing step is up to 45 minutes, preferably between 10 and 30 minutes.

[0039] The mashing water may be introduced at a temperature of 20 to 95°C, preferably 40 to 70°C, more preferably 45 to 60°C.

[0040] The pH of the mash obtained after mashing by the method of the present invention is generally 5.2 to 5.6.

[0041] In particular, the grinding / mashing step is carried out at a peripheral speed of 50-150 m / s, preferably 80-120 m / s, more preferably about 100 m / s.

[0042] The grinding / mashing step of the method according to the invention advantageously allows the production of a finely ground product suitable for filtration of the wort in a membrane filter press.

[0043] The present invention also relates to beer produced from the wort obtained using the above-described method and / or the above-described mill.

[0044] These and other aspects of the present invention will be elucidated in the detailed description of specific embodiments of the invention, with reference to the drawings. [Brief explanation of the drawings]

[0045] [Figure 1] FIG. 1 is an overall view of a crusher and its accessories. [Figure 2] FIG. 2 is a cross-sectional view of the inside of the crusher. [Figure 3] FIG. 3 is a cross-sectional view of the inside of the crusher. [Figure 4] FIG. 4 is a detailed perspective view of a portion of the grinder. [Figure 5a] FIG. 5a shows a detailed view of two embodiments of the knife. [Figure 5b] FIG. 5b shows a detailed view of two embodiments of the knife. DETAILED DESCRIPTION OF THE INVENTION

[0046] Detailed Description of Specific Embodiments (Devices) of the Invention

[0047] FIG. 1 shows all the elements of a mill according to the invention. A feed hopper 11 is used to supply the material to be ground in the grinder 1. A motor 12 drives the rotor 4. The ground material flows through a line 14 to a buffer tank 13 and then through a line 15 to the brewing vessel. It is also possible to arrange the grinder above the brewing tank. In this case, the ground material flows directly into the tank.

[0048] In Figures 2 to 4 (realization 2), it can be seen that the mill 1 consists of a grinding chamber with an inlet 2 for the green malt grains and an outlet 3 for the ground material, and a rotor 4 with a horizontal axis, on which disks 5 are mounted. The number of disks depends on the capacity of the mill, i.e. the size of the grinding chamber. The disks have holes on their periphery for the passage of a horizontal shaft 23. An impact element is suspended in a pendulum-like manner on the horizontal shaft 23, which passes through the disk 5.

[0049] The impact elements can be hammers 6 and / or knives 7. Their shape and material can vary. In the illustrated embodiment, a rectangular hammer 6 and a beveled knife 7 made of stainless steel are used.

[0050] For clarity, the impact elements are shown as they rotate.

[0051] In fact, when rotating, the impact element does not remain fixed in this position but can rotate on its axis.

[0052] In Figure 4 we can see an embodiment with four axes 23 and therefore four rows of impact elements. The first and last item in each row is a knife 7. Between each disk a rectangular hammer 6 is placed.

[0053] 5, the knife 7 is rectangular in shape with two corners of its periphery cut and sharpened, and therefore has six sides: a rectangular base 20 facing the rotor 4, a distal end with two beveled sides 21, and a flat top 22.

[0054] The oblique sides 21 are sharpened to reduce their thickness. The sides 21 may be smooth (FIG. 5a) or toothed (FIG. 5b).

[0055] The rotor 4 operates at a standard rotational speed, imparting a high peripheral speed to the hammers, preferably in the order of 80-120 m / s, more preferably 100 m / s. The rotor alternates between clockwise and counterclockwise rotation to produce symmetrical wear on the lateral surfaces of the impact elements. The lower part of the grinding chamber is equipped with a sieve 10, i.e., a curved perforated plate. The side of the sieve facing the outside of the grinding chamber is called the back side, and the side facing the rotor is called the front side. When applied to germinated grains, the size of the sieve holes can be 1 mm to 4 mm.

[0056] The grinding chamber includes water injectors 8 and 9 arranged at different positions. In an embodiment, the water injectors have flat or conical spray heads. The number of water injectors depends on the size of the grinding chamber. At least one water injector 8 is arranged at the top of the grinding chamber, on the side of the raw material inlet (or inlet 2). This injector 8 sprays water directly into the grinding chamber. Its role is to provide a water flow through which the raw material (green malt) can be swept and to facilitate the passage of the ground grain through a perforated sieve 10. In an embodiment, the number of injectors at the top of the grinding chamber is four. These water injectors 8 are referred to as "main" injectors. The amount of water injected is calculated proportionally to the green malt flow rate, taking into account the ratio required to obtain the desired wort concentration. To obtain a thick wort at 20-24°P (degrees Plato), this flow rate is 1-1.5 liters / kg, taking into account the high water content of green malt grains. If there are multiple water injectors, the water flow is divided between them.

[0057] The lower part of the grinding chamber, which collects the ground material after it passes through the perforated sieve 10, also contains at least one water injector 9, referred to as a "secondary" injector. This example includes four injectors located in this area of ​​the grinding chamber. These injectors 9 spray water onto the underside of the sieve 10. Their role is to ensure that the underside of the sieve 10 is cleaned during and after the grinding process.

[0058] The combined action of the injectors 8 and 9, located at different points within the grinding chamber, allows the raw material to pass through the sieve 10 while preventing buildup and clogging on either side of the sieve.

[0059] The total amount of water used during the grinding process is calculated to leave some capacity to rinse the grinding chamber and the underside of the sieve 10 after the material has passed through. The total amount of water supplied to the main and secondary injectors is considered the green malt mashing water. This water is therefore process water at the desired temperature for mashing the brew, and can be corrected for its pH level and contains additives that are usually added to mashing water, such as enzymes or salts.

[0060] The material coming out of the mill consists of a suspension of crushed green malt and mashing water. This is pumped directly into the stirred tank, where the brewing process begins. This process therefore combines two stages: crushing and mashing. For this reason, this process should be carried out for a maximum duration of 45 minutes, preferably 10-40 minutes, and more preferably 15-30 minutes. The capacity of the mill must be calculated taking this aspect into account.

[0061] According to another advantageous embodiment, the device has a larger capacity.

[0062] The mill used is an impact mill equipped with an 18.5 kW motor rotating at 3000 rpm. This motor directly drives the mill's horizontal rotating shaft (or rotor 4), on which 10 equally spaced discs 5 are mounted. Each of these discs 5 has four circular holes, arranged at 90° angles to one another, into which a metal rod, or shaft 23, is inserted along with pivotally mounted impact elements. The motor drives four rows of 11 impact elements, which rotate at a peripheral speed of 100 m / s.

[0063] The sieve 10 installed has holes with a diameter of 2.5 mm.

[0064] Of course, other arrangements can be envisaged without departing from the scope of the invention. The rotor of the mill can be arranged in a horizontal position instead of a vertical position. In this case, the vertical sieves can also be arranged all around the circumference of the milling chamber. Some of the injectors will preferably be designed to inject water directly into the milling chamber, while other injectors will be designed to inject water behind the sieves. [Example]

[0065] Example of the method according to the invention

[0066] [Example 1] Example 1 details a method for producing wort from green malt using a wet hammer mill, as described below.

[0067] (Green malt) The green malt used in this study is made from spring barley of the "Sebastian" variety that has undergone the malting stage up to germination, which is stopped after 5 days. The green malt thus obtained has a moisture content of 37-43%.

[0068] (Crushing / Mashing) The prototype mill used is a hammer mill equipped with a 9.2 kW motor operating at 2900 rpm. This motor drives the mill's horizontal rotating shaft (rotor 4), on which five equally spaced discs 5 are mounted. Each of these discs has four circular holes, arranged at 90° angles to one another, into which metal rods 23 with pivotally mounted hammers 7 are inserted. The motor drives four rows of six hammers, which rotate at a peripheral speed of 100 m / s.

[0069] The sieve fitted has holes with a diameter of 2.5 mm.

[0070] A mixture of water and grain is produced in the grinding chamber.

[0071] The water and grain flow rates are set so that the milling process is completed in 15 minutes.

[0072] The grain feed rate is set at 3-5 kg / min by a worm means at the start of the grain hopper 11, and the water flow rate is adapted to achieve an instantaneous mashing ratio between 0.8 and 1.3 litres / kg (litres of water per kg of green malt). The mashing water temperature is 45-55°C.

[0073] At the end of the grinding process, a certain amount of rinse water is used to drain any remaining particles from the grinding chamber and to wash the sieve 10. The volume of this water is set to achieve a total mash ratio of 1.5 litres / kg.

[0074] In this first example, 37.5 kg of green malt was milled in a humid environment using 56.3 liters of water. All the green malt was milled in 11.5 minutes and 7 liters of water was used to rinse the milling chamber.

[0075] The resulting mash is then pumped from the buffer tank 13 via piping 15 to the brewing tank.

[0076] (Wort production) After adjusting the pH to 5.5 with phosphoric acid, the mash is milled under water and then subjected to a brewing process where the enzymes in the green malt break down the starch into sugars. - 45°C for 10 minutes - 63°C for 20 minutes - 72°C for 20 minutes - 78°C for 5 minutes

[0077] Heating with a temperature increase of 1°C / min and temperature maintenance at various stages is ensured by direct injection of low pressure steam into the product.

[0078] The mash is then filtered using a three-chamber filter "Meura 2001 Hybrid Micro" with a nominal total capacity of 33 kg of malt. The filtration cycle follows a series of classic steps (filling, filtering, pre-pressing, washing, final pressing, discharge, discharge of spent grain) with parameters optimized to obtain 138 liters of wort at 12°P.

[0079] The wort turbidity measured by the Imhof-Korn method was 4-5 ml / l, which is typical for wort made from malted barley and filtered through a Meura 2001 Hybrid filter.

[0080] [Example 2] In Example 2, a method for producing the same green malt wort as described in Example 1 using an impact mill as shown in FIG. 4 is described in detail.

[0081] The first and last impact elements of each row are sharpened in the shape of knives 7, as shown in Figure 5b in this example. They are made of steel, grooved and toothed, and of the same length. The other impact elements, located between each disk 5, are simple rectangular hammers.

[0082] Thus, in contrast to Example 1, this crusher comprises a combination of hammers 7 and knives 6 .

[0083] At the same output, 37.5 kg of green malt was crushed in 10.2 minutes, which was an 11% reduction in time compared to Example 1. By replacing some of the rectangular hammers 6 with knives 7, it was possible to improve the crushing effect of the root sprouts and the "elastic" moist outer skin that characterize green malt.

[0084] After brewing and filtering, 128 liters of wort was obtained at 13° P. The use of the knife reduced the time in the filtering stage by 12%, and the wort had a turbidity of 4-5 ml / liter, similar to that measured in Example 1.

[0085] [Example 3] Example 3 details a method for producing a green malt-based wort using a new type of impact mill operating underwater, as described below.

[0086] (Green malt) The green malt used was the Planet variety, which had been malted until the germination period lasted 5 days. The moisture content was 32%.

[0087] (Crushing / Mashing) The crusher used is an impact crusher that functions underwater, as shown in Figures 1 and 2.

[0088] The horizontal shaft 4 of the mill is driven by an 18.5 kW motor 12 with a frequency converter which rotates at a nominal speed of 3000 rpm.

[0089] The shaft 4 supports ten equally spaced stainless steel discs 5. Each of these discs has four circular holes arranged at 90° angles to one another, into which are inserted metal rods 23 with pivotally mounted impact elements 7. The motor thereby drives four rows of eleven impact elements which rotate at a peripheral speed of 100 m / s.

[0090] In this example, all impact elements are stainless steel knives with smooth cutting profiles, as shown in Figure 5a.

[0091] The sieve 10 installed at the bottom of the grinding chamber has holes with a diameter of 2.5 mm.

[0092] A grain and water mixture is produced in the grinding chamber. The grain is fed to the mill from the grain hopper 11 at the top 2 of the grinding chamber. A buffer installed at the bottom of the hopper 11 transports the grain to the mill. Hydration of the grain is carried out by injecting water at different points in the grinding chamber via nine injectors 8, the openings of which are adjusted to achieve an instantaneous moisture ratio close to 1 litre per kg of grain. The mashing water used has a temperature of 45-55°C during the grinding process, and a specific rinse volume is added at the end of the grinding process to drain any remaining particles from the grinding chamber and to clean the sieves.

[0093] In this example, 104 kg of green malt grain was milled at a flow rate of 9.3 kg / min with a flash water flow rate of 9 litres / min, resulting in a flash ratio of 1 litre / kg. The milling process lasted 11 minutes, and 44 litres of rinse water was added at the end of the milling process to achieve an overall ratio of 1.38 litres of water per kg of grain.

[0094] The resulting mash is then pumped from the buffer tank 13 via piping 15 to the brewing tank.

[0095] (Wort production) The settings applied for brewing are the same as those described in Example 1. The mash is then filtered using an eight-chamber filter "Meura 2001 Hybrid Micro" with a nominal total capacity of 87.5 kg of malt. The filtration cycle follows a series of classic steps (filling, filtering, pre-pressing, washing, final pressing, discharge, discharge of spent grain) with parameters optimized to obtain 396 liters of wort at 13°P.

[0096] The wort turbidity measured by the Imhof-Korn method was 2-3 ml / l, which is typical for wort made from malted barley and filtered through a Meura 2001 Hybrid filter.

[0097] (advantage) The main advantage of the present invention is that it proposes a method for producing wort from green malt without the need for a kiln drying step, which consumes a lot of heat energy. The use of green malt as starting material for the production of wort reduces production costs.

[0098] The present invention solves the problems associated with the grinding of the root sprouts and wet husks that characterize this material.

[0099] Also, the combination of grinding and mashing in a single step and the high enzymatic potential of green malt to promote enzymatic reactions during brewing can result in significant time savings in the wort production process.

[0100] Furthermore, the present invention makes it possible to simplify the device and reduce its occupied size.

[0101] The present invention is particularly suitable for the continuous production of wort.

[0102] Implementations have shown that the arrangement of knives increases the capacity of the mill in terms of weight of material ground per kilowatt-hour. A number of knives can be arranged on the rotor disk to replace some or all of the rectangular hammers.

Claims

1. An impact crusher (1), a casing surrounding the grinding chamber; At least one rotor (4); impact elements (6, 7) pivotally mounted on a shaft (23) driven in rotation by said rotor (4), said impact elements being hammers (6) and / or knives (7); Equipped with The casing has an inlet (2) for raw material and an outlet (3) for comminuted material, The casing is provided with injectors (8, 9) for water, Crusher.

2. A grinder as described in claim 1, characterized in that the grinding chamber is equipped with a sieve (10).

3. 3. A crusher according to claim 2, characterized in that an injector (8) is arranged to supply water directly into the crushing chamber.

4. 3. A crusher according to claim 2, characterized in that an injector (9) is arranged to supply water to the rear side of the sieve (10).

5. Crusher according to claim 1, characterized in that it has 4 to 8 shafts, preferably 4 shafts.

6. 2. Crusher according to claim 1, characterized in that the impact elements on the same axis (23) are knives (7) and hammers (6) arranged alternately.

7. Crusher according to claim 1, characterized in that the majority of the impact elements are knives (7).

8. Crusher according to claim 2, characterized in that the sieve (10) has holes with a size between 1.0 mm and 4.0 mm, preferably between 2 mm and 3 mm.

9. 9. Use of a grinder according to any one of claims 1 to 8 for grinding green malt.

10. A method for producing wort, comprising:

1. A method according to claim 1, wherein green malt or other germinated grain having a moisture content greater than 15% is fed into an impact mill and subjected to simultaneous grinding and mashing processes.

11. 11. The method according to claim 10, characterized in that a grinder according to any one of claims 1 to 8 is used.

12. 11. A method according to claim 10, characterized in that the mashing water is introduced by means of injectors (8, 9).

13. 11. The method according to claim 10, characterized in that the total amount of mashing water introduced is sufficient to obtain a ratio (water / green malt) of 0.5 to 3.0 liters / kg, preferably 1 to 2.0 liters / kg.

14. 13. The method according to claim 12, characterized in that part of the mashing water is introduced by an injector (8) arranged to feed water directly into the grinding chamber, and another part of the mashing water is introduced by an injector (9) arranged behind a sieve (10).

15. 13. A method according to claim 12, characterized in that the grinding / mashing process is carried out at a peripheral speed of the order of 80 to 120 m / s, preferably 100 m / s.

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