The Forestry Forum

General Forestry => Drying and Processing => Topic started by: Bnewman712 on May 20, 2018, 08:53:46 PM

Title: Kd150 dry and wet bulb settings help
Post by: Bnewman712 on May 20, 2018, 08:53:46 PM
Anyone have any good setting for it. Mostly do walnut oak and cherry and  from 300bf to 800
Title: Re: Kd150 dry and wet bulb settings help
Post by: GeneWengert-WoodDoc on May 21, 2018, 07:16:37 AM
This is covered in DRYING HARDWOOD LUMBER.  Basically, use as warm a temperature as possible up to the value in the standard schedules, and use the EMC or RH in the standard schedule.  Ok? 9when you do this, the WB depression will be the same, or very close, to the standard schedule.
Title: Re: Kd150 dry and wet bulb settings help
Post by: WDH on May 21, 2018, 07:58:02 AM
Also, the manual should have a chart for initial set-points based on species group and moisture content.
Title: Re: Kd150 dry and wet bulb settings help
Post by: Bnewman712 on May 21, 2018, 10:32:33 AM
Yes I seen the chart but when I looked online and talked to them they said that you can change what they put in there for works better on woods so just asking if anybody knows of better ones
Title: Re: Kd150 dry and wet bulb settings help
Post by: YellowHammer on May 21, 2018, 01:36:39 PM
They should be a good starting point, although I've not seen the KD150 Schedules, specifically.  However, an easy way to reduce risk is to back the moisture conditions off the wood about half a schedule step.

The kiln is made by Nyle and their schedules are pretty mild, so just be a little slow on them, switch schedule steps until well into the next moisture region of their schedule.     
Title: Re: Kd150 dry and wet bulb settings help
Post by: GeneWengert-WoodDoc on May 22, 2018, 07:30:50 AM
Note that the standard schedules I mentioned above are conservative.  They are also based on 300 feet per minute air flow, which most DH kilns do,not have, so they are again conservative.  Using a cooler temperature then the maximum that the standard schedule specifies is also conservative.  Hence, there is room for some acceleration without quality-loss risk by using a slightly lower humidity than specified at higher MCs, assuming that you know the wettest MC.  If you air dry first, do not use a higher humidity than what the lumber has been used to in air drying...about 65% RH or 13% EMC for most of the USA.  With drying air dried, or when at the lower MC part of a schedule, we do not use a lower RH than in a schedule, as we can overdry some pieces, creating more cup and more chipped grain when machining.

The conservativeness in the schedules with DH means that with some white woods, like maple, holly, eastern white pine and ash, we might be unable to dry as fast as required for the whitest color.  Reducing the amount of lumber in the kiln can help in this aspect, allowing us to achieve lower humidities in the schedules at the higher MCs.  Generally, above 40% MC is when color is determined.