Lignomat PK Setup guide

Installation and Operators Manual for Lignomat’s PK System
In-Kiln-Moisture-Monitor

Installation and Operators Manual for Lignomat’s PK System
Contents:
1. Installation Manual
Page
1.1 Layout 2
1.2 Installation of Angle Connectors 2
1.3 Installation of Cable Clamps 2
1.4 Cutting and Hanging Cables 3
1.5 Completion of Measuring Station and Cable Run 4
1.6 Completion of Exit Points 4
1.7 Installation of Switch Box 5
1.8 Checking Cables and Connections 5
2. Operators Manual
2.1 Probing Packages 6
2.2 Placing EMC Probes 7
2.3 Obtaining EMC Readings 7
2.4 Obtaining Moisture Readings 8
2.5 Optimization of Kiln Performance 8
2.6 Maintenance and Check-up 9
2.7 Parts List 9
EMC, Relative Humidity, Dry/Wet-Bulb Chart 10
1

The PK system (in-kiln-moisture-monitor) gives reliable and easy obtainable infor-
mation about EMC (equilibrium moisture content) and MC (wood moisture content)
from several different probes distributed throughout the kiln. Moisture readings
can be obtained at the switch box outside of the kiln. The kiln operator can take
readings whenever necessary. After evaluation of the moisture readings against
the predetermined drying schedule, necessary changes in the climate settings can
be made. Thus the kiln operator will be able to run the kilns following the changing
moisture content; there will be less degrade, output and quality can be optimized.
1.1 Layout
The switch box mounted outside the kiln is connected with teflon cable to a series
of angle connectors mounted inside the kiln wall are permanently installed. A set of
removable cables is used inside the kiln to make the connection from angle con-
nectors at the wall to the probes in the lumber.
First, the location of the switch box and the location of the angle connectors should
be determined. The switch box should not be more than 60 feet away from the
kilns. Usually the angle connectors are mounted in pairs, referred to later as one
measuring station. The drawing on page 4 shows possible arrangements for MC
and EMC angle connectors. When determining the cable routing, consider that all
permanently mounted cables should be installed where no damage from lumber
packages being moved in and out of the kiln may occur.
1.2 Installation of Angle Connectors
Once the layout has been determined the angle connectors should be mounted first
- directly to the walll with plastic anchors on cinder block kilns or sheetmetal screws
on metal kilns. All screws must be stainless steel. A silicon base caulking should be
used to seal all holes including screw holes. Most silicon caulks have acetic acid
bases, which will cause masonry to deteriorate. There are caulks available with non
corrosive bases.
Possible groupings for MC and EMC are shown on page 4. For EMC points an
extra angle might be necessary to point EMC holder towards the interior of the
kiln. The EMC holder should be mounted in the air stream before the air enters the
stack of lumber. An aluminum drip shield should be mounted above each measur-
ing station to prohibit condensed water, pitch, acids, or boiler chemicals from falling
on the measuring station.
1.3 Installation of Cable Clamps
Before the cables can be installed, the cable clamps must be mounted. Each clamp
can hold several cables. Plastic wall anchors or No. 6 sheetmetal screws can be
used. The first clamp should be about six inches away from the measuring station.
Installation Manual
2

Working toward the switch box and the the next station continue to mount the
clamps about 3 ft apart. If another station is encountered, place a clamp directly
over the station, then continue with normal spacing. Clamps for cables around door
frames, corners, or for exits should be positioned as shown on page 4.
Photos show double angle connector installation with drip shield.
When routing cables in a metal kiln, columns are an obvious obstacle. Drill a 3/4
inch hole in the column and place a bushing in it to protect the cable. The cable exit
hole to the switch box or from one kiln to the next should be only slightly larger than
the diameter of the cables. By keeping the hole as small as possible it will be easi-
er to seal.
1.4 Cutting and Hanging Cables
Special teflon cable is used to make the connections from the measuring stations to
the switch box. The cable comes in 100 meter rolls. The cable is twisted, as a result
of this it always comes off the roll with twists and kinks. To avoid this problem, first
place the roll in one hand and pull the cable directly off the free side. Take off about
10 coils, then switch the roll to the other hand and pull off 10 more. Most of the tan-
gles that do occur can be taken care of when the cable has been cut to length.
Always start to cut the longest cable first. Never cut any cable exactly to length,
leave at least three feet extra on both ends (for extreamly long runs leave even
more extra). cables in it and hand tighten the clamp screws. Hang all the cables for
the entire kiln all the way back to the switch box. Once the measuring stations are
properly connected, the excess of the cables will be pulled back toward the switch
box.
3

1.5 Completion of Measuring Station and Cable Run
Start with the longest cable run first. If there is more than one kiln, start with the
kiln that is the furthest away from the switch box. The conections between the an-
gle connectors and the cables are the next step. Use three pieces of shrink tubing
for each cable - one piece about six inches from end to prohibit untwisting, two
pieces to cover soldering point and cable insulation at ring connectors. The tubing
can be shrunk by heating it with a heat gun. Be carefull not to damage the insula-
tion.
After soldering and placing the shrink tubing, the ring connector can be secured to
the stainless steel lugs at the appropriate angle connector. Repeat for each angle
connector until the measuring station is completed. Then tighten the first cable
clamp so the cables are held secure but so that they can be pulled through the
clamp without damaging the insulation. Working back to the next station, secure
each clamp leaving about a two to three inch sag in the cables between clamps.
Cables around corners, door frames, and exit points should never be pulled tight,
but have small loops to allow expansion in the hot kiln.
An aluminum drip shield should be mounted above each measuring station to pro-
hibit condensed water, pitches, acids, or boiler chemicals from collecting on the
EMC holder or connections.
1.6 Completion of Exit Points
Once the measuring stations are completed and all cables suspended and clamped
throughout the interior of the kiln(s), the exit points to the next kiln can be sealed.
All exit holes should be sealed.
4

1.7 Installation of Switch Box
All cables coming from the inside of the kiln(s) to the switch box are pulled through
the exit hole which should be made as small as possible. The exit hole should be
sealed completely. Allow the caulk to dry before completing the connections, thus,
maintaining a good seal in the hole. Pull cables inside of switch box and mount the
box. Use shrink tubing on each cable, strip and presolder each individual wire and
connect each pair to the appropriate point inside the box. See drawing bellow.
1.8 Checking Cables and Connections
To check, connect the moisture meter to the BNC connector on the switch box and
dial all measuring stations. Short one measuring station at a time and take a read-
ing at that switch position; this will verify all conections and cable continuety. At this
time it is recomendable to note which angle connector (location of measuring sta-
tion and kiln) is connected to which dial at the selector switch.
To measuring Probe 1
Selector Switch
BNC Connector
(Connection for Lignometer)
5

2.1 Probing Packages
Usually the packages are probed while loading the kiln. This way while unload-
ing the kiln the measuring cables and probes can be retrieved from the packages
coming out of the kiln and used for the next kiln charge. This way only one set of
measuring cables and probes is necessary. If production flow requires probing the
package earlier, two sets of measuring cables might be required.
If certian boards in a stack should be probed, an easy way to identify the selected
board within the stack is to put an “X” on the layer in which the board is, and an “X”
on the end grain of the board. The probed board should never be located close to
the “edge” of the package because the outer zone might dry faster and not be rep-
resentative for this package.
There are two ways to probe a package:
1. Part of the package is lifted with a forklift. If the row is marked with an “X”, lift
everything above the “X”. Pull out the marked board and place the probes.
2. From the top of the package the upper layers of boards are put aside and a
board in the center of the layer is equipped with probes.
Two holes have to be drilled for the probes with a 5/32 inch drill bit 1 1/4 inches
apart, making sure the probe will bottom out in the hole. To hammer the probes
into the board put the pulling tool on the probe head. Do not put pin through holes.
Hammer on top of the pulling tool until the tool touches the wood. The probes are
now placed correctly so that the probe head does not touch the wood and prohibit
the drying process just above the measuring point. The tip of the probe should at
least penetrate 1/3 of the board. Attach the cable to the probes and and put the
package back together making sure the cable is not squeezed by lumber or stick-
ers. The other end of the cable is left hanging outside the package. Once a row is
completely loaded, cable(s) from that row are plugged into the nearest angle con-
nector(s). Now check that probes and cable(s) are producing a reading.
6

2.2 EMC Measuring Station
Once the kiln has been loaded the last thing to do is place the EMC holders. A new
cellulose wafer should be used for every kiln charge. Check and clean the EMC
station if necessary. Dirty angle connectors and EMC holders affect the EMC read-
ings. EMC readings are also used to check a dry-bulb-wet-bulb measuring station.
Angle connector with EMC holder and
EMC wafer for direct measurements
of EMC.
Dry-bulb-wet-bulb thermometers with
measuring plate and wet sock bottle.
2.3 Obtaining EMC Readings
The EMC can be read with the Lignometer K and the Ligno-VersaTec directly in
percent. For EMC readings the meter should be set to the setting specified on the
wood group card for EMC. All EMC values should be temperature compensated by
dialing the drying temperature inside the kiln at the moisture meter Lignometer K or
Ligno-VersaTec.
After dialing the wood group and the air temperature in the moisture meter and se-
lecting the corresponding station at the selector switch, the EMC can be read at the
moisture meter directly in percent. Conversion charts are not necessary. 2 Charts
are included showing the relation between EMC/MC and relative air humidity (see
page 9), and dry bulb-wet bulb temperature (see page 10).
7

2.4 Obtaining Moisture Readings
Once the kiln has been brought up to tem-
perature, accurate moisture readings can
be taken. Set the wood group switch as in-
dicated by the specification chart provided.
Find the actual temperature inside the kiln
after heating-up has been completed and the
temperature inside the kiln is stabalized; the
drying temperature is the same as the wood
temperature. All MC values should be tem-
perature compensated by dialing the drying
temperature inside the kiln at the moisture
meter (Lignometer K or Ligno-VersaTec).
After dialing wood group and temperature at
the moisture meter, temperature and wood
group compensated moisture readings can
be obtained directly in percent. Connect the
meter with the BNC connector at the switch
box and dial each station seperatly at the switch.
To fully benifit the PK system, readings should be taken every day and recorded
with the climate conditions present in the kiln at the time. Before each change of
climate settings the readings should be evaluated against the predetermined drying
schedule.
Evaluation of recordings throughout several drying cycles is an important tool for
the kiln operator to work towards the most efficient and economical drying cycle for
their kilns.
2.5 Optimization of Kiln Performance
Due to the flexibility of the PK system, the location of probed packages can be
changed with each kiln charge to determine if there is a difference in the drying
process between top, bottom and center packages. Monitoring different loactions in
your kiln will help evaluate overall kiln performance and show slow drying areas.
Specific boards can be selected for probing with high initial or low initial moisture
content. Comparing measurements will indicate which boards should be probed in
the future for an optimized kiln schedule.
If too much lumber is degrading, the drying schedule should be changed and a
moisture content based schedule can be applied to be assure high lumber quality
at the end of the drying.
With the PK system the kiln operator has a tool on hand to optimize kiln perfor-
mance and to produce high quality, perfectly dried lumber.
8

2.6 Maintenance and Check-Up
Before every kiln charge a visual check should be performed to see if the perma-
nently installed cables are intact. The measuring stations and the EMC holder can
be cleaned with alcohol or aceton. The cables going from the measuring stations to
the wood probes should also be visually checked for worn or broken insulation.
For a thorough check, all measuring cables should be tested as follows: Plug the
cable into a measuring station and take a reading from the moisture meter with
nothing connected to the probe end of the cable. Now emerse the whole cable into
a bucket of water making sure the cable ends are not shorted or in the water. Take
another reading; if that reading is higher then the first, the cable is bad. If the dam-
aged part of the cable can be located heatshrink could be applied to fix the insula-
tion. If not, the bad cable needs to be replaced.
5
1.4
1.4
1.4
1.3
1.3
1.3
1.2
1.2
10
2.6
2.6
2.6
2.5
2.5
2.4
2.3
2.3
15
3.7
3.7
3.6
3.6
3.5
3.5
3.4
3.3
20
4.6
4.6
4.6
4.6
4.5
4.4
4.3
4.2
25
5.5
5.5
5.5
5.4
5.4
5.3
5.1
5.0
30
6.3
6.3
6.3
6.2
6.2
6.1
5.9
5.8
35
7.1
7.1
7.1
7.0
6.9
6.8
6.7
6.5
40
7.8
7.8
7.9
7.8
7.7
7.6
7.4
7.2
50
9.5
9.5
9.5
9.4
9.2
9.1
8.9
8.7
45
8.7
8.7
8.7
8.6
8.5
8.3
8.1
7.9
55
10.4
10.4
10.3
10.2
10.1
9.6
9.7
9.5
60
11.3
11.3
11.2
11.1
11.0
10.8
10.5
10.3
65
12.4
12.4
12.3
12.1
12.0
11.7
11.5
11.2
70
13.5
13.5
13.4
13.3
13.1
12.9
12.6
12.3
75
14.9
14.9
14.8
14.6
14.4
14.2
13.9
13.6
80
16.5
16.5
16.4
16.2
16.0
15.7
15.4
15.1
85
18.5
18.5
18.4
18.2
17.9
17.7
17.3
17.0
90
21.0
21.0
20.9
20.7
20.5
20.2
19.8
19.5
95
24.3
24.3
24.3
24.1
23.9
23.6
23.3
22.9
Relative Humidity EMC Table
T °F
30
40
50
60
70
80
90
100
9

Fig. 19: Moisture content equilibrium of timber (according to R. Keylwerth and data
from the U.S. Products Laboratory, Madison 1951). Example:
With a dry-bulb temperature of 45 degrees C and relative air humidity of 55% re-
spectively a wet bulb temperature of 36 degrees C, the wood equilibrium moisture
content is 9%.
10