Destoner PKV-3 with vibro-pneumatic principle of operation is designed for separation of solid mineral impurities from cereal grains, oilseeds, legumes and other crops, commensurable with the size of main crop.

Destoner PKV-3 is designed for separation of solid mineral impurities from grain.

Destoner PKV-3 is produced in accordance with third category of GOST-15150, climate version “U” for internal market and export to temperate countries. However, machine has to work reliably in operating regimes at a temperature from 10 (°С) degrees below zero to 40 (°С) degrees above zero, relative moisture 80% with average annual temperature of 15 (°С) degrees above zero, atmospheric pressure from 650 to 800 mm Hg (86,6÷106,7 kPa).

One-, two- and three shift operating mode.


Parameter title  Value

Throughput (rated), kg/hour








Table oscillation frequency, с-1

(oscillations /min)


Table oscillation range, mm




Impurities separation level, %


Air consumption, m3/min (m3/hour), max.


Rated power, kW


Dimensions, mm:








Weight, kg, max.


Structure and Functioning

Destoner consists of the following main parts (fig.2): body 2, frame 2, deck with metal wire mesh 3, feeder 4, aspiration chamber 5, aspiration valve 6, loading nozzle 7, unloading nozzle 8, stones discharge nozzle 9.

Machine operates in accordance with the following technological process. Product, supplied to the machine through loading nozzle 13, is distributed along the inclined plane 6 by special valve, which prevents air suction to the machine from loading pipe. Loosening of the grain layer is occurred under the influence of rising air current and sorting surface vibration, when grain is supplied to the deck. Conditions for efficient separation of different-type components are created in such layer: heavy particles flow down into the lower layers reaching the sorting surface, and particles with lower density speed to the upper layers. In the layered mixture, a process of vibrational displacement of different-type components occurs in opposite directions. Without airflow all mixture components move upward along the sorting surface. Under the influence of air, grain layer flows under a slope and is discharged in the bottom of the deck plate. Heavy mineral particles are transferred upwards against the deck plate slope and removed through the upper nozzle.

The following factors may significantly influence the destoner efficiency and throughput capacity: frequency, amplitude and direction of oscillations (vibrations), air flow speed, deck plate slope and difference in the density of grain and mineral foreign matters, loading and moisture content. Air, used in the process of layering, contains dust and light product fractions, and is cleaned in the cyclone or in the filter. Recommended connection scheme of the destoner is shown on fig.3. 


Optimal conditions for product sorting are provided by proper adjustment:

- air consumption;

- dividing plane slope;

- position of the stones discharge valve;

- oscillation range;

- air consumption adjustment.

Nozzle of the air suction system is equipped with throttle valve controlled by the fly wheel. Air consumption adjustment is carried out in order to ensure air speed necessary for normal product layering. Heavy particles and stones are falling to the bottom of dividing plane, and light particles float so to avoid influence of the operating plane vibrations. Air volume required to reach specified results depends on the quantity and type of the product, and is gradually brought to obtain a uniform “fluid bed” layer along the entire dividing plane. With low air flow speed on the deck plate operating surface product would start the motion along deck plate and its side surface to the heavy fraction outlet and stones discharge. In this case it is necessary to increase the air flow speed on the deck plate operating surface gradually to the light “fluid bed” effect. Formation of "fountains" is not allowed, in case of their occurring speed of the air flow should be reduced.

Adjusting of the dividing plane slope

The adjustment is occurred due to flywheel rotation of slope adjustment mechanism – clockwise for top part lifting and back for table back-end lifting. The purpose of the adjustment is to reduce the speed of product motion towards the stones discharge porthole. If the adjustment is correct, the product layer thickness gradually reduces with apprising to discharge port hole.

Stones discharge valve

Valve made of transparent plastic material and driven by flywheel is installed over the port hole for stones discharge. Flywheel rotation reduces the height of free passage between wire mesh and valve edge, and thereby increases airflow speed in this zone. The purpose of the adjustment is to intercept the product and to avoid its discharge with stones. Valve must be in the lowest position when starting the machine. With entering of the first stones, valve should be gradually upraised to ensure stones passage to the discharge porthole, and the product must stop at a certain distance from the valve edge and be directed to the side unloading nozzles for heavy products.