Scheme of conventional drying kiln with heat recovery unit (new)
Completely automated drying Drying of all types of wood regardless of the starting moisture content Communication Electrical energy consumption: 80 to 200 kWh per m3 of timber for entire drying cycle (for fans only) Installed power 3 to 5 kW/m3 Uses hot water or steam as working medium Maximal working temperature 80 °C Environment friendly	Conventional kiln scheme: Servo-controlled flaps Flow fans Heaters False - ceiling Atomizers Substation Heat recovery unit

Wood dryers: Conventional kilns Dehumidifying dryers Mini (Low-cost) kilns (NKS) Heat pumps Additional equipment Power electric switch board Catalogues and manuals: Wood dryer catalogue (.pdf 3.7MB) NIGOS dryers (.pdf 956KB) User manuals Measurement&controll equipment catalogue (.pdf 2.8MB)

Automatic controllers for wood drying: MC-411R, MC-412, MC-900R, MC-502R, MC-600, MC-2000 Automation of existent conventional kilns Archive (obsolete products no longer produced):  (MC-100RM, MC-500R, MC-100R, MC-1000) Wood MC meters: Portable moisture meter RVD-904 Nondestructive moisture meter DVD-241 Nondestructive moisture meter MCD-50 Other: Control unit for steaming chambers PD-02 ISPM-15 wood pallet sterilization unit MKS-05

Conventional way of drying is most frequently used way of drying wood because the kilns are technically very simple, even for large capacity kilns (over 100 m³ of timber). They do not require extra maintenance and electrical power consumption is reduced by using wood wastes as fuel for boiler.

In recent years all conventional drying kilns made by NIGOS have "heat recovery units" also known as "recuperators" installed. Heat recovery units are installed in order to reduce the use of heating energy. Drying is achieved by the replacement of inner damp air with outer drier air. Without hat recovery units, all heated air is blown out and heat loss is great. When heat recovery unit is installed, the air that is leaving the chamber exchange heat energy with the air coming into chamber. This way heating energy is saved up to 30%. Apart from apparent heating energy saving, use of reuperators also shortens time of drying and increases drying quality of timber. Investment in heat recovery units is minimal and return of investment period is very short.

Hot water or steam can be used as a working medium at conventional wood dryers i.e. conventional drying kilns. We must point out that this type of dryer is recommended for companies which have large amount of sawdust, wood chips and other wood waste.

Main form of conventional kiln is given at the schematics above. Optimum ventilation is provided by the reversible fans mounted above the aluminium false-ceiling. These fans move air through the whole timber stock (in both directions). The air is then reheated on the heaters (heat exchangers), if needed. Moisture from wood traverse into air under the influence of temperature. When the flaps are unfolded, part of the dump air is ejected out of the kiln chamber through the flap K2 (K1) carrying wood moisture with it. Simultaneously, same amount of fresh air enters the kiln chamber through the flap K1 (K2). Fresh air mixes with inner dump air, circulates through the stock, and the process is repeated (as long as the drying lasts). Equable circulation through all wood stocks is achieved by mounting  false - ceiling made of aluminium. Fresh air that enters the kiln chamber through flaps is colder (especially during winter), so the heaters must work all the time to maintain requested temperature inside the chamber. Drying temperature is 80 °C maximum.

It is logical to conclude that the energy consumption at this type of kiln is relatively high
(80 to 200 kWh per m³ of timber for entire drying cycle for flow fans alone), so the energy is almost always used from the boiler. Installed power is approximately 3 to 5 kW per m³ of timber. Air velocity depends on the chosen drying regime but is mostly around 2 m/s, except for the hard drying regimes for which it can achieve up to 5 m/s. Consequently, this requires flow fans much stronger than the ones used at dehumidifying kilns (their power is approximately 0.25 kW per m³ of timber).

Equipment delivered with each dryer is placed inside the kiln which can be constructed or assembled of aluminium bearing structure. The power electric switch board is placed in suitable room outside the drying chamber.
 
"NIGOS - electronic" gives its customers 1 year warranty for whole kiln, and 5 years for the automatic control unit.



Technical data

Model	Average capacity (m3)	Heating power of boiler (kW)	Flow fans	Electrical power of fans cca(kW)	Optimal dimensions of chamber (axbxh)(m)
VKS-30	30	160	3 x Ø800	9	4.6x6.5x5.2
VKS-40	40	160	3 x Ø800	9	4.6x8.2x5.2
VKS-50	50	240	4 x Ø800	12	6.8x7.0x5.2
VKS-60	60	240	4 x Ø800	12	6.8x8.2x5.2
VKS-60A	60	320	6 x Ø800	18	8.6x7.0x5.2
VKS-80	80	320	6 x Ø800	18	8.6x8.2x5.2
VKS-100	100	400	8 x Ø800	24	10.6x7.0x5.2