Saw blade cooling/cleaning in saw mills:
Spraying a very fine water mist on the saw blades, they will both be cooled and cleaned. A cooled saw blade ensures a long saw life. A clean saw blade will make is easier to sharpen, increase the feed speed and reduce the saw kerf. Only a little water mist is sprayed out (each nozzle is between 4-16 litres per hour/1-4 GPM) and the water will therefore evaporate before it hits the ground preventing unwanted water puddles. As a bonus, the water mist sprayed on the saw blade will knock down some of the fine airborne saw dust, as the dust gets heavy when it gets in contact with the high- pressure water mist.
Humidity control in dry kilns:
Humidity is added in the dry kiln at the end of the drying cycle to ensure an equal moisture content, as the lumber at this point is drier on the outside compared to the inside. The alternative ways of adding the humidity is either steam or low pressure water mist.
a) High-pressure water mist versus steam
Steam is expensive to generate (either gas fired or furnace), and the more the boiler is used to generate steam, the more maintenance and thus chemicals to add to the boiler are required. The water mist on the other hand is very cheap to produce, which makes the pay back time rather short – especially if you already are at the limit of your boiler capacity and is considering buying a new boiler.
When conditioning lumber by adding humidity, the uncontrolled temperature rises occuring with steam are undesired due to the risk of super heat that damages the lumber. With water mist it is much easier to stay at the desired humidity level, which shortens the conditioning period and gives a better conditioning resulting in a much better stress relief in the lumber.
b) High-pressure water mist versus low-pressure water mist
High-pressure water mist is sprayed out at 80-100 bar/1150-1450 psi pressure, whereas low pressure is done at 5-25 bar/70-350 psi. The droplet sizes are much smaller at high pressure ensuring a fast evaporation in the air. The bigger droplets from a low pressure system will on the other hand not evaporate immediately and may cause water stains on the lumber stacks. With high-pressure water mist it is easier to control the exact desired humidity level and that means that the lumber conditions much faster in comparison with low-pressure water mist systems.
Dedicated pump skids for wood processing:
Danfoss has designed dedicated pump skids adapted to the specific requirements in these wood applications. The service needed is at the absolutely minimum and there are several built-in safety devices protecting the system.
