Horizontal sunflower impact dehuller NRH-8 of continuous action is designed for dehulling of oilseeds at the enterprises of fat and oil industry.

Booklet NRH-8

Flyer NRH-8

Horizontal sunflower impact dehuller NRH-8 (referred to below as machine) of continuous action is designed for dehulling of oilseeds at the enterprises of fat and oil industry.

The machine is produced in accordance with third category of GOST-15150, climate version “U” for internal market and export to temperate countries. However, dehullers have 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).

Single-, double-, triple-shift mode.


Parameter title
  NRH-8       NRH-4-01
Capacity (depending on processing intensity), max. tons per day
  150   80
Speed, rpm 
with frequency-regulated drive
without frequency-regulated drive:
with engine pulley                 Ø125
Rotor diameter,  mm
800 800
Rotor width,  mm
2150 1280
Rated capacity,  kW 2х9,2+0,75=19,15 11,0
Air consumption for aspiration,  m3/h
1400 800
Specified service life prior to capital repair,
years min.
5 5
Specified total service life
8 8
Overall dimensions, mm: 
                        with silo bin over the feeder

1715 (1915asp)

1715 (1915asp)
Weight, kg (max.)
2740 (2880)   1750 (1800)
Qualitative operating characteristics 
Commercial mixture
Large seeds

Content, %:



unhulled seeds



partially hulled seeds









half kernels (chop)



Oil containing dust, %



Structure and Functioning

The machine (fig.1) consists of body frame 1 (where bearing cartridges are installed and hold rotor 2), deck plate 3 and deck plate holder 4, lower 5 and upper 6 mechanisms for regulation of clearance between rotor and deck plate, feeder 7, adjustable curtain 8, drive 9, retaining walls 10 and 11, aspiration channesl 12 (as machine doesn’t have its own fan, it is connected to the central aspiration pipe-line). Rotor 2 is rotated by V-belt transmission due to actuating motor, which is installed on the back wall 21 of the machine.

Feeding roller 14 is rotated by individual gear motor 15 and placed in the feeder 7. Due to the throttle 16 and feeding roller 14, product is distributed over the entire width of the feeder and supplied to the feeder 17 tray, which serves for grain supply to the functional area between rotor and deck plate (dehulling chamber), feeder can be optionally equipped with magnetic protection. In the chamber dehulling of seeds is occurred by numerous hammers impacts and seeds removal to the seamy surface of deck plate.

After dehulling, kernels and hulls are transferred to the outlet of the machine by the curtain.

Intensity of seeds dehulling in the chamber is regulated by the clearance adjustment between deck plate and hammers. Figure “0” at the tie rod bolt scale, with tightened locking nut, corresponds the minimal clearance 6…8 mm. between deck plate and rotor. During adjustment of minimal clearances, to avoid damage of the deck plate upper stop, lower clearance indicator value should not exceed upper clearance indicator value by more than 20 mm. And to avoid deck plate skewing, difference between side indicators should not exceed 1 mm.

ATTENTION! To avoid failures, adjustment of clearance between deck plate and rotor and curtain inclination angle must be carried out when engines are turned off, after rotor complete shutdown. After adjustment of clearances and inclination angle, it is necessary to remove protection and turn rotor by the pulley manually. Rotor should rotate easily, without abnormal noise and seizing. Afterwards the motor can be turned on and the machine can be started out.

To achieve designed capacity, proceed as follows:

1. Normal circumferential speed of the beater must be installed at the level 25 m/sec. that corresponds 600 rpm, seeds distribution over the entire width of the drum can be achieved by the regulation of throttle in the feeder.

2. Distance between hammers and seamy surface of deck plate must be adjusted in accordance with grain type and its moisture content.

Reduction of this distance and increase of circumferential speed improves seeds dehulling, but at the same time increases chop (half kernels) formation process and dust content.

Adjusted position of deck plate seamy surface towards beater and selected circumferential speed must provide the capacity specified in product certificate.

3. The flow of transferred seeds must be adjusted by regulation of slot between valve and ribbed roller.

4. Set the normal air mode in dehulling chamber.

Speed of air flows must be regulated to avoid seeds transfer to light tailings during intensive aspiration.

During machine operation it is necessary to control the following parameters:

1)    load of the machine must be stable, as decreasing or increasing of the load reduces operation efficiency;

2)    operation of the feeding roller and valve, equal seeds distribution over the entire length of the roller;

3)    curtain position;

4)    normal air conditions and seeds blowing, elimination of airspaces and leakiness, both in the machine and in the aspiration system, which may break down air conditions by outside air inflow;

5)    bearings state and their lubrication, preventing creeping of grease and heating of bearings;

6)    normal operation of drive belts and their tension;

7)    protection constructions for pulleys and belts;

8)    keep the machine clean, periodically clean the machine from accumulated dust and metallic contaminants in the magnetic protection, keep the tools clean (brush, scoop, scraper, vacuum cleaner, sponge with soapy solution).

In case of slap inside the machine or other facts that indicate about the malfunction, it is necessary to unload and stop the machine, identify the reasons of slap or other malfunctions and eliminate them. After that the machine can be re-started. With 24-hour operation the machine must be stopped after 10-15 days of continuous running for periodic internal inspection.

The following parameters must be checked:

1.    State of the seamy surface of deck plate (shift the lower tie rod bolt to the minimal clearance position and upper tie rod bolt – to the maximal clearance position, carry out the inspection through the upper connection door). In case of strong runout of deck surface, deck sections must be replaced.

This calls for the following steps:

a)    fix the cable of hoisting device to the lugs in the deck plate upper part;

b)    remove upper link assembly, then upper and middle front walls 19 and 20, remove lower link assembly and lower wall, and take the deck out of the machine by hoisting device;

c)    replace deck sections and reassemble in reverse order.

2.    State of the hammers (in case of strong runout of the hummers and generation of featheredges, it is necessary to replace them or provide the following operations with used hammers: rotate them to the outside of the drum with unworn surface, balancer drum on the knives or in the bearing blocks, after removing the grease in accordance with “Technical maintenance”, paragraph 3).

3.    Distance between hammers and deck plate surface.

The machine operates in accordance with following technological process (fig.3):

Product, which must be dehulled, enters to the inlet nozzle and through feeder is transferred to receiving tray and further to functional area between rotor and deck plate. After dehulling between deck plate and rotor, product is removed from the machine through outlet port located in the floor. The air flow moves against dehulling seeds and carries over light particles and hulls through aspiration duct. Probe sampling is carried out through special access doors 22.

To ensure the normal machine operation gate valve or throttle must be installed before inlet nozzle. The magnetic protection also must be obligatory installed.