Dumpling Production Equipment and Automatic Pelmeni Making Machines

Pelmeni (dumplings) are produced through a continuous sequence of operations: preparing the dough and the filling, forming the dumplings, freezing them, then packaging and labelling. A complete pelmeni production line consists of a filling-preparation unit, a pelmeni forming machine, a machine for separating frozen dumplings, a quenching (tempering) drum, and machines for dosing and sealing the dumplings. The dough is mixed in dough-kneading machines from flour combined with a salt solution and either melange, fresh food whey, or sodium caseinate.

What does a pelmeni forming machine do?

The pelmeni forming machine is a continuous-action machine that mechanically shapes and produces dumplings from dough with a meat-filling centre. As shown in Figure 1, the machine is built around a welded frame-type bed (1) carrying a belt conveyor, which comprises a drive drum (2) with a belt (3) on its shaft and a screw-type tensioning station (4).

A rubberised conveyor belt (5) is fitted over the drums, running on support rollers, with support drums (6) located at the dumpling-stamping section. Two stainless-steel hoppers are installed beside the conveyor — one for loading dough (7) and one for loading filling (8). Dough is fed into hopper (7), from where a screw (9) draws it and delivers it into an accumulator cylinder (10).

From the accumulator cylinder, the pressure created by the screw forces the dough into a collector-distributor (11) and then into the forming device (14). The filling travels from hopper (8) through screw (12) into collector (13), and then likewise into the forming device (14).

How does the forming device shape the dumplings?

The forming device is the principal working element of the pelmeni machine, consisting of two tubes — dough is fed into one and filling into the other. At the end is an outlet through which the dough emerges under pressure as a continuous tube, with the filling supplied into the inside of that tube.

As the dough tube with its filling centre leaves the forming device, its own weight flattens it, and it settles onto the conveyor as a continuous ribbon. The conveyor speed matches the rate at which the tube exits the forming device nozzle and can be adjusted.

In the described design of the SUB-3M pelmeni machine there are three stamping drums (17) and forming devices, so during operation three parallel tubes of filled dough are produced simultaneously. Figure 1 — Schematic of the SUB-3M pelmeni machine: 1 — bed; 2 — drive drum; 3 — sprocket; 4 — tensioning station; 5 — conveyor; 6 — support drum; 7 — dough hopper; 8 — filling hopper; 9 — dough-feed screw; 10 — accumulator cylinder; 11 — collector-distributor; 12 — filling-feed screw; 13 — collector; 14 — forming device; 15, 16 — flour-dusting devices; 17 — stamping drum; 18 — drum-lifting mechanism.

How is sticking prevented during forming and stamping?

To stop the dough tube sticking to the conveyor belt, a flour-dusting device (15) is installed ahead of the forming head to coat the belt. A second dusting device (16) of the same design is positioned downstream along the conveyor, dusting the dough tube itself with flour so it does not adhere to the stamping drums. Flour consumption for dusting is roughly 20 kg per tonne of dumplings.

The filled dough tubes, resting on the conveyor belt or on supporting trays, reach the stamping drums — steel discs fitted with cells that cut two rows of dumplings from a single tube. Under the weight of the stamp pressing on the dough tube, the filling is squeezed into the cells while the dividing edge presses the dough right through, forming the individual dumplings.

When the machine is started or its operation is being adjusted, the stamping drums are raised using lifting mechanisms (18).

How are pelmeni frozen?

Pelmeni are frozen in an SMA-1 type freezing apparatus (Figure 2) — a demountable, insulated chamber (1) measuring 3100 × 2000 × 1650 mm, inside which a chain roller conveyor (2) is mounted, carrying blades (3) at every 40 mm. Beneath the conveyor sits a drive station (4) made up of an electric motor, a worm reducer, a speed variator and a chain drive that turns the conveyor sprocket.

Evaporators (5) are installed on both sides along the conveyor, right against it, built from finned copper tubes 16 mm in diameter. Air is supplied by an EVR-2 type centrifugal fan (6) driven by a second electric motor. Air ducts (7) run from the fan perpendicular to the evaporators and conveyor, so that the air is blown through the evaporator, cooled, and then moves through the conveyor, making three full circuits.

The evaporator-air-coolers are enclosed in casings and have pans to collect the water produced when the frost layer ("snow coat") is removed by special defrosting devices, with the water carried off through drains (10). The air temperature for freezing the dumplings is −30 °C and the air velocity over the product is 1.6 m/s. The evaporators are cooled by a freon compressor.

Dumplings are loaded through window (8) together with the trays on which they were stamped. The trays take a vertical position and advance by means of the conveyor blades, completing one full circuit around the conveyor before being discharged through window (9). The conveyor speed is set with the variator so that the dumplings remain in the apparatus for 25–30 minutes, during which they are frozen to −14 °C.

At any one time the conveyor holds 125 trays of dumplings. While travelling along the lower branch of the conveyor, the trays are held in place by devices fixed to the conveyor blades. At the end of the conveyor a discharge device (11) directs each tray towards the unloading opening (9).

The apparatus is equipped with an interlock device and a light indicator that signals any mechanism faults. The chamber temperature is monitored by a single-position thermostat, while the operation of the two-stage FDS-1M freon unit is regulated automatically by instruments (pressure relays on the refrigerant suction line). Figure 2 — SMA-1 type pelmeni freezing apparatus: 1 — freezing chamber; 2 — roller conveyor; 3 — conveyor blades; 4 — drive station; 5 — evaporator; 6 — centrifugal fan; 7 — air duct; 8 — loading window; 9 — unloading window; 10 — drain; 11 — discharge device.

How is pelmeni dough prepared?

Pelmeni dough is prepared in filling mixers fitted with screw blades of any system and capacity, as well as in "Standard" type dough-kneading machines with an open 330-litre bowl. The "Standard" dough-kneading machine is shown in Figure 3.

The main working part of the "Standard" dough-kneading machine is a shaft (5) with a blade (6). The arm carrying the blade (6) moves up and down in a circular motion while the bowl (7) simultaneously rotates around its axis (15). This combined rotation of the blade and the bowl ensures thorough kneading of the dough. Figure 3 — "Standard" dough-kneading machine: 1 — bed; 2 — electric motor; 3 — transmission pulley; 4 — reducer worm; 5 — mixer shaft; 6 — blade; 7 — dough bowl; 8 — bowl cap; 9 — cap pivot axis; 10 — trolley; 11 — eye wheel; 12 — automatic latch; 13 — worm; 14 — guard; 15 — bowl rotation axis; 16 — mixer-lift handwheel.

In batch-action mixers the dough is kneaded for 25–30 minutes until a uniform, thick mass is obtained. The temperature of the finished dough should be 26–28 °C. Pelmeni dough must be homogeneous and elastic, must seal well along the seams during stamping, and must not disintegrate in water. Its moisture content should be 38–40%.