RU177834U1 - MOBILE CROSS-SHAPED KNIFE OF FOOD GRINDER - Google Patents

Abstract

The blade knife (movable knife) of the food chopper refers to devices used both in the food industry and in domestic conditions for grinding meat and other food products. The blade knife (Fig. 1) contains a hub 1 with a bore hole 2, on which the blades 3 are located, having additional cutting blades 4 with cutting edges 5 on the rear surfaces. The additional cutting blades have an arcuate shape and are located on concentric circles. Each cutting blade (Fig. 4) has two cutting edges 5 and 8. The crushed product is pressed under pressure onto the cutting edge 5 and cut (cut) by it. Moreover, when the blade rotates, the cutting blade 4, overcoming the resistance of the grinding medium, by its cutting edge 8 also dissects the product. Thus, in the design of the knife lies the possibility of implementing simultaneous preliminary and final grinding of the product. The energy efficiency of the moving knife of the proposed design has been experimentally confirmed. In all cases, ceteris paribus, energy costs were 35 ... 37% lower.

Description

The utility model relates to the elements of the cutting mechanism of the grinder of technological raw materials for food production and can be used both in the food industry and in domestic conditions.

The known design [RF Patent No. 2220771 “Blade knife”, patent holder V. Serebryakov] in the form of a four-blade knife: “The blade knife contains a hub with a landing hole, on which blades are placed, having a cross section in the form of a parallelogram with cutting blades on opposite surfaces , the blades have a cross-sectional area decreasing from the hub to the periphery, while reducing the cross-section of the blade from the hub to the periphery is made by reducing the length of the sides of the parallelogram lying in the plane and cutting and / or by decreasing the acute angles of the parallelogram from the front and / or rear surfaces of the cutting, the blade can be folded circumferentially on archimedean spirals in logarithmic spirals. The blades of the knife along the cutting blades from the side of the cutting plane can be equipped with protrusions having a parallelogram or trapezoid shape in cross section. The landing hole of the knife can be a square and a hexagon combined with two opposite faces, having a common center. The invention improves the cutting properties of the knife and reduce energy consumption when grinding the product. "

It is known that a tool intended for dividing (grinding) a product into parts should have a blade in the form of a classic wedge with a pointed angle α of no more than 5 ... 6 °. The cross section of the knife, from the point of view of energy efficiency, cannot be in the form of a parallelogram, trapezoid, square or any other geometric shape. Therefore, the proposed design cannot be considered energy efficient.

Also known is the design of a four-feather knife [SU 1791020 A1] to a food chopper, mainly meat, containing a body with a central hole and curved blades formed by the intersection of the rear and front surfaces of the feathers. It is argued that, in order to reduce grinding forces, the cutting edges of the blades are formed by segments of circular arcs whose centers lie on the adjacent feather, while the cutting angle of each blade is 35-50 °, and the front surface generatrix is straight.

If the cutting angle, according to the inventor, is 35-50 °, then the point angle at the top of the cutting blade will be α = 55-40 °. Such an angle of sharpening of the cutting blade, as shown by elementary calculations, is not optimal from the point of view of energy consumption for the grinding process.

Maybe the author of the invention was guided by the geometric parameters of the blade of a metal cutting tool, adopted in metalworking. Ensuring the strength of the cutting edge of the blade of a metal cutting tool is a very complex and difficult task, which can be solved, among other things, due to geometric parameters (angles). In the design of parts of the grinding mechanisms of food choppers, such a problem practically does not occur.

In the invention [Knife to devices for grinding meat and meat products, 632392, B02C 18/36; A22C 17/00; IN AND. Ivashov S.G. Yurkov) V.K. Bubyrenko, N.M. Dvorak] the authors tried to create a design of a movable knife that meets some requirements for food machines and apparatuses. The design of the knife provides for a replaceable part, which can be made of more than a knife body, wear-resistant material. In the description of the invention, it sounds as follows:

“The knife to the meat chopping devices comprises a blade holder 1, on each blade 2 of which there is a replaceable cutting blade 3, fixed at one end.

The proposed design of the knife can reduce blade wear and increase tool life by 2.5-3 times. "

To some extent, the authors were able to satisfy one requirement for food equipment (nobody has fully succeeded in this yet), namely: “Food machines and apparatus must have high wear resistance of working bodies in order to prevent metal particles from entering the processed product.”

Depreciation of the working bodies, regardless of what materials they are made of, always has and will take place. Another thing is the intensity of this wear.

We should not forget that meat is a perishable product. If during the grinding process it will fall into cracks, cavities or other places difficult to clean, then this can lead, after the next grinding, to severe food poisoning (damage to the crushed product).

The design of the knife provides threaded holes, recesses for countersunk screws and other slots. It is not necessary to rely on the operator serving the machine to disassemble the knife every time after the shift and to remove pieces of meat that are stuck there from the recesses, slots and holes. And this will not be necessary if in its inventive activity it is guided by the principles of compliance with the requirements for food machines and devices, namely:

“Machines and apparatuses should consist of separate aggregates and units that are easily connected to each other for quick disassembly and assembly after periodic sanitization of machines, as well as during their installation and repair. On the external and internal surfaces of machines and apparatuses and parts in contact with the product (except for special cases), there shall be no cracks, sinks, cavities, protrusions and sharp corners that are difficult to access for washing and cleaning. ” This requirement in the design of the knife is ignored.

In addition, the angle of sharpening of the cutting blade is 90 °, which is also not optimal from the point of view of energy consumption.

The closest to the claimed technical solution for the technical nature and the technical result achieved is [RF Patent No. 2297282, classes: V02C 18/36 knives or perforated discs, authors Vlasova VK and others.] knife for grinding meat products.

It is claimed that the object of the invention is to improve the quality of grinding meat products and labor productivity. “The problem is solved in that in the knife to the device for grinding meat products, containing blades connected in the form of a cross with cylindrical grooves on the cutting edges and annular cutting edges made at the base of the blades, cylindrical grooves are made on the annular cutting edge at an angle of 15 ° -30 ° to the axis of the knife in the direction of its rotation, and the rear surfaces of the blades relative to the cutting edges are made in the form of triangular recesses and with an inclination relative to the axis of the device, and on the rear surface of the blades Tel'nykh cutting edges, formed at least one cylindrical groove in the form of a spiral of Archimedes ".

Immediately, we note that in the generally accepted terms used there is some liberty to use them. This situation makes it difficult to understand the true goal and methods for achieving it. For example, in FIG. 2 poses 6 denotes the rear surface of the blade 1 and indicates a flat surface, and in FIG. 3 pos. 2 also shows a flat surface, while in the text it has the name “Cutting Edge”. In addition, the cross section is hatched so that the blade is prefabricated. But nothing is said about this in the text. To say that "... blades with cylindrical grooves on the cutting edges ..." is not very correct.

The Polytechnic Dictionary says: "The cutting edge is the edge of the tool blade, formed by the intersection of the front and rear surfaces of the blade." Therefore, the cutting edge is a line (straight or curved) and there can be no cylindrical grooves on it.

Another thing is the blade - “The tool blade is a wedge-shaped element of the cutting tool designed to penetrate into the workpiece material and to separate the layer from the material." There may be grooves of any shape and size on the blade.

The presented figures (drawings) and the vagueness of the use of generally accepted terms make it difficult to understand some provisions in the text. For example, in the part of the text where the principle of operation of the knife is considered, it is stated: “When the knife is rotated, its cutting edges of the 2 blades 1 cut into the processed product supplied under pressure and ... For the same purpose, the tilt also serves, because changing the length of the cutting edges is provided by changing the angle of inclination of the walls of the triangular grooves 3, made on the cutting edges 6 of the blades 1, at the same time ... Performing on the reverse cutting edges 2 of the surface 6 of the spiral cylindrical grooves 7, made in the Archimedes spiral, allows not only to pre-grind the product , but also provides the supply of meat products, pre-crushed on the cutting edges 4, in the zone ... "

It follows from this text that in FIG. 2 and FIG. 3 poses 2 and 6 have one name - the cutting edge, but this is not so. In addition, the spiral cylindrical grooves 7 to the surface 6 have no relation, because they are located on another surface (other surfaces).

Unfortunately, there is currently no standard for terms applicable to parts and elements of a moving knife for a food chopper. Therefore, using the terminology adopted in food engineering, we distinguish the characteristic surface of the blade, which in cross section is approximately rectangular in shape:

1) the surface of the blade facing the grate and in contact with it is the cutting surface;

2) the surface of the blade located on the opposite side of the cutting surface is the rear surface;

3) the surface of the blade, which is adjacent to the cutting edge and is transitional between the cutting surfaces and the back - the front surface.

The patent for the invention of IPC 2297282 В02С 18/36 is adopted as a prototype of the proposed utility model.

It is alleged that "The objective of the invention is to improve the quality of grinding meat products and labor productivity."

And how to improve the quality of grinding meat products? For example, by reducing energy costs for the process of grinding food, at least you can maintain the quality of the feedstock in the crushed product. The meat should be cut, not rubbed and lose juice!

From FIG. 2 and FIG. 3 it follows that the front surface forms an angle of 90 ° with the cutting plane (the point angle at the tip of the blade). This angle is not optimal in terms of energy efficiency. From the point of view of energy efficiency, this angle should not be more than 6 ... 8 ° in the designs of grinding mechanisms of food products. From this point of view, the cross section of the blade of a knife can only take the form of a classic wedge. Then the blade will not have a front surface. In this case, the cutting surface intersects with the rear surface, forming a cutting edge, which can be rectilinear, curved, zigzag, etc.

Further, in the description of the principle of operation of the knife, it is stated that "... Performing on the reverse cutting surface 2 of the spiral cylindrical grooves 7 made in the spiral of Archimedes, allows not only to carry out preliminary grinding of the product, but also provides ...".

In other words, the authors tried to combine the preliminary grinding of the product with the final one in the design of the knife. But in the grooves of a cylindrical shape, even if they are made in a spiral of Archimedes, how can grinding of the product, especially meat, occur.

In addition, if the blade of the blade should be made in the form of a wedge taking into account the sharpening α of not more than 6 ... 8 °, then its design in the cross section in the form of a rectangle should be considered unsuccessful. The rotating blade of the knife continuously overcomes the resistance of the ground medium. And this resistance is greater, the larger the area of the maximum longitudinal section of the blade, measured in a plane normal to the working surface of the grating.

Note that in this case, the method of grinding products by splitting (separation) is used. In other words, the process of mechanical disintegration of the product is used, with the help of a working body wedging into it to grind the product without presenting requirements for the shape of the separated parts, while the knife blades should separate the pieces of the product by cutting, rather than tearing them off.

If the design of the blade of the knife met the requirements of energy efficiency, then it would have in any cross section the shape of a classic wedge that does not have a front surface, and on which there can be no triangular grooves or grooves of any other shape.

It is no coincidence that the blades of almost all hand tools designed to separate materials (products) have the shape of a wedge (household knife, household scissors, surgeon's scalpel, gardener's secateurs, etc.). Many thousands of years of experience backed by calculations cannot be ignored.

It is known that almost all products subject to grinding are pre-processed, i.e. pre-divided into pieces of certain sizes. The smaller the size of these pieces, the less mechanical (external) impact the product being ground is subjected to in the final grinding zone.

Traditionally, the designs of movable knives provide elements intended only for final grinding. You can try to design a movable knife so that the preliminary grinding of the product is combined with the final one.

The objective of the proposed utility model is to increase the energy efficiency of food grinding (reducing energy consumption) and, as a result, preserving the quality indicators of the raw material in crushed form.

To solve this problem, a movable knife with blades was designed, on the rear surfaces of which there are cutting blades located along arcs of concentric circles. For pre-grinding the product, the so-called “saw effect” technique is used here. The cutting edge of the blade, even the most even and sharpened, always has micro notches (this is easy to notice under a microscope). It is no coincidence that the sickle, a hand tool in the form of a curved semicircle design, has a finely serrated profile for cutting cereals from the root.

If the blade rotates and the product being crushed (for example, meat) moves on it under pressure along the screw, then the product will be divided into parts with less energy consumption than when the blade is stationary.

Disclosure of a utility model. The technical solution proposed in the utility model is incorporated in the design of the movable knife, which is shown in FIG. 1, 2, 3, 4, 5.

The cross-shaped knife for grinding food contains a hub 1, with a landing hole 2, on which the blades 3 are placed, on the rear surfaces of which there are blades 4 with cutting edges 5 and 8, in addition, the blades have cutting edges 6 (for final grinding) and front surface 7.

Implementation of a utility model. Studies performed with movable knives of the proposed design, mounted on grinders with an electric drive, confirmed their energy efficiency.

The movable knives were made of spring-spring steel (according to GOST 2052-53) grade 65G, annealed at a temperature of about ~ 810 ° C, hardened at a temperature of 830 ° C, cooled in oil, tempered at a temperature of 480 ° C.

Knives were also made of carbon steel of the high grade U13A (according to GOST 1435-74), which differs from high-quality steel with a lower content of sulfur, phosphorus and manganese and a higher purity in non-metallic inclusions, less tint in the thin cutting edge during grinding (sharpening) and operation.

The tests were carried out with both hardened and non-hardened knives (in this case, the hardening temperature is ~ 800 ° C, the cooling medium is oil, and the hardness after hardening is ~ HRC62).

It should be noted that knives made of steel grade U13A, were more energy efficient compared to knives made of steel 65G.

For comparative tests, knives of the proposed design were manufactured and tested, i.e. with cutting blades on the rear surfaces of the blades and without such blades.

In other words, the knives differed from each other only in the presence or absence of cutting blades on the rear surfaces of the blades.

In the process of testing knives, the question arose about the optimal number of cutting blades on the rear surfaces of the blades (per unit length in the radial direction).

Tests have shown that the denser the blades are located (the more they are per unit length), the higher the knife’s energy efficiency.

But the tight placement of the cutting blades on the rear surface of the blade does not fully meet the requirements for food machines and devices, namely: "... there should be no cracks, sinks, cavities, ... difficult to access for washing, cleaning and sanitation."

In the narrow depressions between the cutting blades, the milled product is delayed, which complicates the cleaning process of the knife.

The optimal, according to the results of our tests, should be considered the presence of one cutting blade at a length of 7 ... 10 mm. The energy consumption for the meat grinding process using moving knives of the proposed design turned out to be 35 ... 37% lower compared to the energy consumption for the grinding process with moving knives of the structure proposed in [RF Patent No. 2297282, classes V02C 18/36 knives or perforated disks].

And there is a very simple explanation for this. The presence on the rear surface of the blade of the knife of a cylindrical groove (one), made in a spiral of Archimedes, according to the authors of the patent prototype, allows the grinding of the product. These grooves cannot carry out any grinding of the product, because they do not have cutting edges. Grinding is carried out only by all the cutting edges available on the blades of the movable knife and the cutting edges of the working holes of the lattice.

Of course, energy is consumed for grinding the product with cutting blades located on the rear surfaces of the knife blades. Energy is also spent on the final grinding of the product by the cutting edges of the blades together with the cutting edges of the holes of the grate. The total energy costs for grinding the product with knives of the proposed design were less than the energy costs for the final grinding of the product without preliminary grinding. This situation can be explained from the standpoint of the law of synergy. The law of synergy states that the sum of the properties of a system is not equal to the sum of the properties of its components. The difference between the sum of the properties of a system and the sum of the properties of its components is a synergistic effect.

It should be noted that the complexity of manufacturing a knife of the proposed design increases by 10 ... 12%. Therefore, it may seem that such savings are not of great practical interest.

It should not be forgotten that energy-intensive processes are expensive not only because of excessive energy consumption, but also the equipment on which these processes are implemented is more material-intensive and expensive to operate. In addition, there has been an increase in prices for metals, electricity, gas, almost all consumables and therefore finding ways to reduce unit costs per unit of output is an urgent task.

It has been observed that food grinding processes are extremely energy intensive. For example, industrial grinders of fresh meat, including frozen blocks, have electric motors with a power of 30 ... 55 kW, while the installed capacity of electric motors on metal cutting machines, on average, does not exceed 8 ... 10 kW.

Brief Description of the Drawings:

in FIG. 1 shows the design of a rotating knife (view from the auger side):

1 - the hub of the knife;

2 - landing hole;

3 - knife blade;

4 - cutting blade;

5 - cutting edge;

in FIG. 2 shows the structural elements of the blade located on the rear surface of the blade:

3 - knife blade;

4 - cutting blade;

5 - cutting edge;

9 - direction of rotation of the blade;

in FIG. 3 shows a cross section of a blade located on the rear surface of the blade:

4 - cutting blade;

5 - cutting edge;

α is the point angle at the top of the cutting wedge;

in FIG. 4 shows a view of the blade from the front surface:

4 - a cutting blade on the rear surface of the blade;

5 - cutting edge on the side of the blade facing the screw;

6 - cutting edge on the surface of the blade facing the grate;

7 - the front surface of the blade;

in FIG. 5 shows a longitudinal section of the blade:

4 - cutting blade.

The technical result of the utility model is a cross-shaped movable (rotating) knife with blades having additional cutting blades on the rear surfaces, with which the product is preliminarily ground by cutting (cutting).

The utility model allows you to create a knife design, which, due to the presence of a greater total length of the cutting edges (compared with a knife of a traditional design), provides an increase in labor productivity and the quality of grinding the product. If, for example, meat is minced, it should not be rubbed to a pasty state. To grind the product to a pasty state, there are mills.

The reduction in energy consumption for the grinding process indicates that the knife has improved cutting properties and, as a result, the likelihood of deterioration in the quality of raw materials after grinding has decreased.

Increased energy costs for the grinding process indicate that the product is frayed, there is excessive heating of the details of the grinding mechanism, and this can dramatically degrade the quality indicators of the crushed product. It is important to preserve the chemical and biological properties of the ground material in the ground product. By mechanical grinding of the feedstock, it is not possible to improve the chemical and biological properties in the crushed product, but if the design and operation (with excessively worn knives) are unsuccessful, the combination of a movable knife and grate, the crushed product may not be suitable for use.

Claims (1)

The cross-shaped blade knife used in food choppers, containing a hub with a landing hole on which the blades are placed, characterized in that on their rear surfaces there are additional arcuate cutting blades located on concentric circles.

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