The dies are made of corrosion-resistant, durable materials, such as brass LS59-1 (GOST 15527 - 70), solid phosphorous bronze BrAZh9-4l and stainless steel 1X18Н9Т (GOST 5949 - XNXXX GOST 75-XNXX) In the absence of stainless steel, it is replaced by a less deficient chromium steel of the grades 2XXNNUMX and 13X3 (GOST 13 - 5949).

Types of matrices. Round matrices (fig. 4.5). Established in screw presses for the production of short products, as its shape provides the most efficient cutting of such products; the exception is the LPL-2M macaroni press, where the round matrix has a wider application.

Figure 4.5. Round Matrices

a - with a bed grate; b - with a false grate; in - height 60 mm

The dimensions of the die depend on the performance of the press. In LPL-2M presses, matrices with a diameter of 298 mm are used, in LGTSH presses — 350 mm, in presses of foreign firms - 400 mm and more.

The height of the dies must meet the strength conditions, since in screw presses the dies are constantly under high pressure over the entire area - from 7 to 9 MPa. This pressure especially increases at the moment of starting the press - up to 10 ... 14 MPa.

Matrices with a diameter of 298 mm are manufactured in three sizes in height: 22, 28 and 60 mm. The first two are operated with special support devices - grate bars. In the production of the grate used two types - bedplates and invoices.

In the matrices with bed bars (see fig. 4.5, a) there are two transverse bands 3, with which the matrices are mounted on the edges of the 1 bar bars. The diameter of the 2 sidewall of such grates is equal to the diameter of the round 4 matrix. Grid-iron dies have limited use, as they allow you to mold products that are cut only in the suspended state.

In the matrices with patch grates (see fig. 4.5, b) there is a hole in the central part into which an 2 bolt with two transverse ribs 1 is inserted. Matrix and ribs tightened with an 3 nut.

Matrices with a height of 60 mm (see fig. 4.5, c) have the necessary strength and are operated without grates. This type of matrix is the most common.

Rectangular two-lane dies (Fig. 4.6) are installed in tubes of screw presses to form long products, followed by hanging them on the bastuns. Two-way matrixes are used in presses of automated lines, where two strands of molded products are distributed simultaneously to two bastons. Each strip of the matrix has several rows of forming holes. The number of rows depends on the cross-sectional size of the products: in special pasta dies with a diameter of 5 mm and noodles of a wide section 1 x 4 mm, the forming holes in each strip are arranged in two rows, for pasta

Fig. 4.6. Rectangular two-way matrix

straws with a diameter of 3,5 mm - in - three, for vermicelli with a thin diameter of 1,8 mm - in seven rows.

Rectangular matrices have a length of 955 ... 1245 mm, width of 200 mm. Matrix thickness ranges from 35 to 50 mm.

Forming holes of pasta dies. Forming holes are divided into two types: without inserts for forming thread-like and ribbon-like pasta and with inserts for forming tubular products and some types of shaped products.

Of the matrices with forming holes without a liner, the most widely used are matrices with inserts for the production of vermicelli and noodles. They are made of brass, with a diameter of 298 and a height of 60 mm. Wells are drilled in the matrix disk, inside which inserts are installed, having the form of disks with a diameter of 18 or 20 mm and a thickness of 5 ... 10,5 mm. Holes of different profiles are drilled in each insert (fig. 4.7).

In fig. 4.7, and shows a disk insert 1 for molding vermicelli ordinary diameter 1,5 mm. In the round 102 matrix, there are such inserts, each with 19 fluoroplast-reinforced forming holes. Total in the matrix 1938 holes.

The disk insert has a 3 fluoroplastic gasket 4 mm thick and an upper 2 disk that protects the fluoroplastic from

Fig. 4.7. Disc inserts pasta matrices for molding: a - vermicelli ordinary; b - fine noodles; in - noodles

Forming holes of dies

Section size, mm | The number of disk inserts | The number of forming holes in each insert | The total number of forming holes with a diameter of 298 mm in the matrix |

Vermicelli | |||

1,5 | 102 | 19 | 1938 |

1,2 | 102 | 55 | 5610 |

2,5 | 114 | 10 | 1140 |

Noodles | |||

X 3 1 | 102 | 11 | 1122 |

X 3 1,6 | 120 | 5 | 600 |

X 5 1 | 102 | 11 | 1122 |

X 7 1,2 | 120 | 3 | 360 |

X 7,2 1,2 | 120 | 2 | 240 |

loads and damage if foreign objects get into the well.

Pictured in fig. 4.7, 6 disk insert has 55 holes of diameter 1,2 mm to form a thinner vermicelli. This disk insert has a simpler design; it is not reinforced with fluoroplastic. Matrix for noodles are not much different from matrices for noodles. The only difference is in the design of the disk inserts (Table 4.1). For disc nozzle inserts (see fig. 4.7, c), the forming holes have a cross-sectional shape of a rectangular slit with rounded edges so that the products are not torn along the length.

One of the basic requirements that the forming holes must meet is the presence of anti-adhesive properties. For the molding holes, special fluoroplastic-4 inserts are made. In addition, the forming holes can be polished, chrome, but it is less effective.

The forming hole of the dies with inserts consists of two main elements: a multistage channel of cylindrical shape, drilled in the disk of the matrix, and fixed in the channel of the insert.

In fig. 4.8 presents the forming elements in pasta matrices of various designs for the production of tubular products. In fig. 4.8, and shows the design of the forming element, not reinforced with fluoroplastic. Plasticized dough under high pressure enters the cylindrical part of the opening 5 of the largest diameter, dissected with the liner supports 4

Fig. 4.8. Forming elements of pasta dies of various designs.

a - not reinforced with fluoroplastic; b - with a fluoroplastic ring;

in - for receiving corrugated horns; d - with a three-bearing insert,

into three streams and, bypassing them, enters a narrower transitional part of the 3 channel, where three streams of dough are connected, pre-compacted and, flowing around the stem of the 2 liner, turn into a tube. The final molding and compaction of the product takes place in the forming gap of the 1 matrix.

In fig. 4.8, b shows the design of the forming holes with a fluoroplastic ring 2 stepped profile, mounted on the protrusion 7 of the body of the matrix. The height of the ring corresponds to the height of the forming gap 3. Above the ring is a metal sleeve 4, which protects it from the dough flow pressure and supports the 5 support of the liner.

Both designs of forming elements are used in round matrices with a diameter of 298 mm for forming tubular pasta with a diameter of 5,5 and 7 mm, as well as for forming horns with a diameter greater than 20 mm.

In fig. 4.8, in the forming holes for receiving grooved horns. Unlike pasta, the cones are curved. This is achieved by the fact that 2 has a notch in the 7 stem, as a result, the resistance to dough output through the forming hole on this side decreases, the dough comes out with greater speed and bends the tube into the opposite

In rectangular matrices, the forming element has a three-support insert (see Fig. 4.8, d) with a through hole. This design of the forming element provides the flow of air inside the macaroni tube through the drilled channel in the matrix and through the metal tube insert. The need for such a design is due to the fact that after molding through rectangular matrices, the products are hung on bastuns. In this case, in places where the tube is bent on the bastun or when cutting pasta strands, a vacuum may occur, as a result of which the tubular products may stick together.

Tubular products | Diameter of products, mm | The number of forming holes in the matrix |

Pasta: | ||

special | 5,5 | 600 |

Ordinary | 7 | 420 |

Horns: | ||

smooth | 3,6 | 432 |

corrugated | 5 | 272 |

» | 5,5 | 214 |

smooth | 5,5 | 278 |

special | 5,5 | 600 |

The number of forming holes in the dies with a diameter of 298 mm for forming tubular products is given below.

Basics of technological calculation of pasta matrices. Performance P (kg / s) pasta matrix dry products is determined by the formula:where u is the speed of molding the products from the matrix, m / s (u = - 0,02 ... 0,05 m / s); Рт - density of the pressed dough, kg / m3 (рт = = 1300… 1350 kg / m3); Wт and W and is the humidity of the test and dry products, respectively (% W = 29 ... 32% and W = 12,5 ... 13%); f is the area of the living section of the matrix, m X NUMX.

The area of the living section of the matrix for tubular products f, vermicelli fv and noodles / l is determined by the following formulas:

where n is the number of holes in the matrix;

where d_{0} - diameter of the forming hole, m;

where I and a are respectively the length and width of the forming gap, m.

Washing matrices. A universal LMN machine (fig. 4.9) is used for washing round and rectangular dies, consisting of the following main components: an 9 sump with a drain pipe, a drive mechanism, 3 swing nozzles, a 11 trap tank, a pump, and a piping system with 1, 10 valves .

The 9 pallet is designed as a closed trough-shaped profile with a hinged lid and is installed inside the cast frame, which gives the necessary rigidity and stability to the entire machine.

Fig. 4.9. LMN Matrix Washing Machine

not. The side surface of the frame on the one hand forms the drive gear case, on the other - the supports of the shafts of the washing mechanism. Inside the pallet, on two horizontal axes, there are two 16 and 14 rollers, on which a round or rectangular matrix is placed. On the roller shaft 14 is fixed gear 72, with which is inserted into the gear removable rack 8. On the rail there are stops for fixing a rectangular matrix 7.

The rollers are driven by an 5 electric motor with a power of 0,4 kW, with a rotational speed of 1400 min^{-1} through the worm gear 6 and gear system. The drive has reverse control. The reverse can be automatic and manual. The rotation frequency of the round matrices 1,16 min-1, the speed of the reciprocating movement of rectangular matrices 15,8 mm / s.

Automatic reverse is carried out when washing a rectangular matrix, which in extreme positions through stops with levers acts on the limit switches.

Inside the pallet, on both sides of the rollers, two oscillating pipelines are installed with an individual pump connection. The rocking nozzle devices are driven from a common gearbox using the 4 chain transmission, the 18 eccentric and the 19 link mechanism. The frequency of oscillations nozzle devices 18,3 min^{-1}.

The tank-trap 13 has a trough-shaped form, installed under the pallet and divided by 13, 75 mesh partitions into three compartments. On one side, purified water is collected from the tank through the 7 7 pipeline and pumped through the 2 pipeline to both swing nozzles, on the opposite side, the water contaminated by the test waste is discharged into the tanks.

The electrical equipment of the machine includes two electric motors for the drive and the pump, a control panel, limit switches, and a wiring system. Electric motors have independent control. Start and stop them are carried out from the control panel. On the sides of the pallet there are two limit switches interlocked with the pump drive. When lifting the sump cover, the pump motor shuts off and the water supply to the nozzles is stopped.

On the machine for washing set pre-soaked matrix. Before starting work, from a water heating system, clean water is poured into a trap tank with a temperature of 30 ... 40 ° С to

When washing round matrices, the matrix is placed vertically on the drive rollers and fixed with a limiter. Using the rocker mechanism, the swing angle 25 ° of the nozzle device is adjusted and set based on the sweep coverage of at least half the diameter of the circular matrix.

When washing rectangular dies, a gear rack is pre-inserted, which is engaged in engagement with the driving support roller, and then the matrix is vertically mounted and fixed on the rail. After that, stops are placed, which, acting on the limit switches, reverse the drive, and the rail with the matrix makes a reciprocating motion. Using the rocker mechanism, the swing angle of the nozzle device is adjusted. After performing the marked operations, the sump cover closes and the pump starts.

The pump takes water from the 15 tank trap section and supplies it to two nozzle swiveling devices on both sides of the matrix. The cleaning of the forming holes of the macaroni matrix occurs by the force of the water jet coming out of the nozzles under pressure, while the matrix is washed evenly on both sides. Waste water enters the trap tank and, after passing through all three compartments in series, is cleaned and re-supplied to the pump.

In the process of using the newly purified water for washing the matrices, the polluted water is partially removed, and the intake device is clean. Duration of washing the round matrix 20 min., Rectangular - 30 min. The consumption of washing water for one round matrix 15 l, per rectangular - 25 l.

Rules for the maintenance of matrices. For the maintenance of matrices in proper technical condition, enterprises have schedules for changing matrices, their cleaning, technical inspection and repair. Each matrix is assigned to a specific press and grate, so the number of the press is indicated on the matrix. One matrix is in operation for no more than a day, after which it must be replaced.

Remove the matrix from the press should only be a special puller. When installing the matrix in the ring press can be used

For washing the matrices in the enterprise, a washing compartment is provided, which includes the following equipment and inventory:

- bath for washing matrices;
- bathtub with sockets for the dies of matrices. The nests are located at a height of 150 ... 200 mm from the bottom at a distance of 150 mm one from another. To the top of the bath piped for hot and cold water. To drain the water in the sewer provided a pipe with a grid.
- light stand to check the cleanliness of the matrix after washing;
- special rack or shelf for storing clean matrices;
- cabinet with tools and spare parts for the repair of dies.

The matrix is lowered into the bath for soaking and set on the edge. The temperature of the water in the bath 40 ... 50 ° C, the duration of soaking 10 ... 12 h. After the mastering the matrix is installed in the washing machine. During the inspection it is necessary to pay attention to the size and profile of the holes and liners. The liners in the forming holes must be tightly installed, and the axis of the liner must coincide with the axis of the hole. The edges of the forming slots and liners should not have any burrs.

For technical inspection and maintenance of pasta pastes matrix removed only if necessary.

The inserts are removed and centered using a special mandrel made from Brans 9-4 bronze and having the shape of a tube, the outer diameter of which is taken in accordance with the outer diameter of the forming gap - 0,02 mm and the inner diameter - in accordance with the insert leg diameter + 0,02 mm. Mandrel end rests on the support (shoulder) of the liner, which is squeezed out of the hole matrix.