INTRODUCTION

  Started in 1994, Tritherm has more than 10 years experience in building of timber drying plants and in wood moisture measurements. We have built more than 500 kilns in the region covering Singapore, Malaysia, Indonesia, Myanmar, Thailand, Vietnam, India, Sri Lanka, and China.

TIMBER DRYERS

Tritherm kiln drying equipment, through constant product development and product improvement over the last 10 years, have reached the highest level of Quality and Reliability. Our dryers are efficient, are designed to withstand corrosion, and use the most advance microprocessor based controllers to control the entire drying process.

KILN COMPONENTS

Tritherm kiln components are developed jointly with various manufacturers according to Tritherm's stringent design and materials specifications. Our products are sold to other kiln dryer manufacturers and to customers to replace unreliable or unavailable parts for dryers made by others. Tritherm is the largest manufacture and stockist of kiln dryer components in South East Asia. Having a large inventory of kiln components and spare parts gives our customers the peace of mind when they buy our kiln dryers.

    HEATING PLANTS

The name 'Tritherm' holds in a deep meaning for the company. Being trained in the field of Heat Transfer, the founder had in mind the 3 (Tri) different heating medium used for heating the dryers, namely - Steam, Hot Water and Thermic Fluid. Since drying is under the field of thermodynamics, 'therm' was added to 'Tri' to form the name 'Tritherm'.

We design boiler and heater plants that burn woodwaste or biomass effiently without pollution. We supply steam boilers from 500 kg/hr to 8.000 kg/hr capacity, and hot water and thermic fluid heaters from 300.000 KCal/hr to 3,000,000 KCal/hr.

KILN CAPACITY AND DIMENSIONS

SECTIONAL SIDE VIEW OF A CONVENTIONAL KILN
The picture below shows a cross sectional side viewof a conventional kiln dryer.

FUNCTION OF EACH KILN COMPONENT

1. Heat Exchanger - the heating medium can be steam, hot water or thermic fluid, depending on the type of boiler or heater used. The heat exchanger consist of many finned tubes (to increase the heat exchange surface) welded together. It's function is to transfer the heat from the heating medium to the passing air. Tritherm finned tubes have extruded aluminum fins which is the most efficient for heat transfer. The heat exchanger is subjected to rapid corrosion. It is recommended to use stainless steel base tubes so that the kiln can operate for many trouble free years Carbon steel base tubes have to be replaced regularly, each down time can last a few days to a week.

2. Air Circulation Fans - Airflow is one of the most important factors in the drying of timber the ideal air velocity across the timber stack is 2 m/s. For some wood with pressure impregnated chemical treatment where the initial moisture can be as high as 150% the airflow has got to be even higher, up to 4 m/s. The high airflow will help to quickly evaporate the large amount of free water, thus reducing the drying time the fans have reversible flow and are rotated in the opposite direction at every 4 hours interval. This is to ensure that the timber is dried evenly at both ends of the kiln.

The kiln motor driving the fan is normally 3 Kilowatt and has to be with Class H windings. The kiln chamber can be very humid and moisture ingress into the motor can damaged it. Therefore, the motor enclosure has to be at least IP55. It is advisable that the motor be fitted with drive ends, greasing points and grease overflow outlets the bearings should be greased every 3months. This will enhance the motor bearings life. The grease used must be the high temperature type suitable for temperatures up to at least 200 degrees C.

3. Aluminum Damper - Some call it Vent. When the air in the room becomes too humid or wet after absorbing the wood moisture, an air change is required. The kiln controller will signal the actuators to open. Depending on the direction of the airflow, the dampers or vents on the high pressure side of the fan will act as exhaust to dump the moisture laden air, and those on the low pressure side will act as intake to bring in fresh dry air When the controller senses that the air humidity has reached the desired level, it will signal the damper actuator to close.

4. Damper Actuator - As describe above, the actuator is to operate the dampers. A common shaft linking a row of dampers will transmit the turning motion of the actuator to each damper. Since there are two rows of dampers, two dampers are required for each kiln The damper actuators are designed to rotate 90 degrees to open or close the vents The linkage connecting the vents together has to be checked periodically to ensure that they are fastened tightly to the shaft so that no slippage occurs.
 

5. Motorized Heating Valve - When the kiln controller senses that the kiln temperature is below the set temperature, a signal will be sent to open the heating valve allowing the heating medium to enter the heat exchanger to heat up the room. The valve will closed when the controller senses the set temperature is reached. For steam heating, a Motorized 2-way globe valve or ball valve is used. For heating by hot water or by thermic fluid, a 3-way diverting valve is used. The heated oil or water will be directed to flow into the heat exchanger when heat is required. When the temperature has reached the set temperature the fluid is directed by to the heater.
 

6. Steam Trap - For a steam heated kiln, when the steam loses heat in the heat exchanger, it turns into water. To remove the water only without taking losing the steam, a steam trap is required. Most kiln manufacturers use the low cost thermodynamic type, which is not very efficient in removing water without also releasing steam. More heat is lost using this type of trap. Tritherm uses only the float type steam trap which has a high water removal capacity and releases only water and not steam along with it.

7. Spray Valve. The spray valve is activated by the kiln controller when it reads a low humidity condition in the kiln room. In the case of a steam heated kiln, steam is sprayed to humidify the room. If thermic fluid or hot water is used as the heating medium, then water spray is used. The water, however, has to be atomized into a fine mist in order to be absorbed by the air. The spray valves and spray nozzles are very dirt sensitive, it is imperative to place a 100 mesh strainer before the spray valve.

8. Spray Line- this is the pipeline inside the kiln connected to the spray valve. For steam spray, small holes of 3 mm diameter are made at 30 cm interval to release the steam into the kiln room. For water spray, atomizing nozzles are attached to the spray line. It is advisable that stainless steel pipe be used, as corrosion can cause the holes or nozzles be clogged up. These nozzles have to cleaned and washed regularly.

9. Sub-Ceiling - This is a divider between the fans and the wood stacks so that the air flows from one end of the room to the other end without short-circurting.

10. Fan Control Panel - This controls the sequential starting of the fan motors so that there is no power surge. It is also for changing the fan rotation at a regular interval. Safety features must be built-in. When a motor overloads, when one power phase is down, or when there is a leakage, the panel will be automatically tripped. The panel must also indicate when any of the motor is tripped or not running.

11. Main Sliding Door-This is normally a lift and slide door made of aluminum. Insulation is placed inside the aluminum panels to prevent heat lost from the kiln. The aluminum door extruded frame profile allows a rubber seal to be slide in place to provide good sealing when the door is closed.

12. Door Trolley - This is a shared device for opening the main door. It has a built-in mechanical or hydraulic lifter to lift the door. When the door is fully lifted, the trolley can slide along the door rail to open up the kiln dryer 

13. Kiln Controller - This is the heart of the system. The Tritherm TX 2000 kiln controller uses the latest micro-processor technology in its circuitry. It is fully automatic and programmable. There 60 factory set drying programs in memory. The user can modify any of drying schedules in memory or program their own custom schedules and save them into 18 user memory locations. The controller uses the most accurate and fundamental dry and wet bulb temperature sensors to measure the dryer's temperature and humidity. The TX2000 is very user friendly and easy to operate. It has 4 wood moisture measuring points which can automatically temperature compensated. It has safety interlocks that will shut circulation fans and the heating valve when a dangerously low humidity or high temperature condition is encountered. Options are available to connect up to 32 units of TX2000 controllers to a centralised computer for central control and monitoring. The software allows the printing of the drying data at periodic intervals and also allows the data to be achieved.