The NEOSYSTEMS-II FUEL & SOIL MOISTURE METER from Sigma Delta Technologies is designed to measure the moisture content of forest matter & soils. In nearly every case moisture meters are checked by using an oven. A sample is weighed and then put into an oven. After a period of time (when all the moisture has gone from the sample), the sample is removed and the loss in weight is the moisture content. In the case of forest matter this can take up to 24 hours, depending on species type. It usually involves a minimum of 1 full day's wait until the results are known. To get over this long drying period, various methods have sprung up to measure other parameters and infer moisture content from the results. Some of these are electrical conductivity, calcium carbide, RF means, capacitance, etc. Some of the disadvantages of these methods are:
* Because of the wide range of moisture values, the input impedance required is very high when measuring at the lower levels. It requires very little changes on the input to give an incorrect reading.
* Because of the variety of plants
and leaves, the electrical conductivity varies between species. This
means that you may have to have a calibration curve for each species.
* Profile moisture measurements are not possible because of the wide variations in moisture content.
Sigma Delta Technologies decided to go back to basic principles. The oven is the absolute method but you cannot get enough heat into the samples quickly without burning them and the process takes too long.
The NEOSYSTEMS-II uses an oven that compresses the sample between two hot plates, thus providing good thermal contact with the sample. A high flow rate pump is used to remove the moisture-laden air from the oven as well as reducing the vapour pressure within the sample compartment. Sample preparation consists simply of cutting the pieces into sizes of about 1 cm square. With samples of less than about 15%, simply "crunching" them up in the hand is sufficient. The meter takes up to 35 grams of sample. The analyser is portable and operates from a normal car battery. It has simple controls and is easy to operate. Field measurements can be made and the results are known within a few minutes.
The switch panel used to control the analyser, indicate oven heating and power and display results, diagnostics, instructions, etc on the display.
The unit is switched on and initialised. During initialisation, the mechanics are set to the initial state (lift motor down, traverse mechanism to a position over the balance - home) and the operator opens the lid and places the sample on the pan, within the sample holder. The sample holder is placed within a ring which is used as the guide for transport. The operator then closes the lid, presses START and the measurement commences. The analyser will wait until the operating temperature of the oven is reached and then tare the balance by moving the sample away from the balance. The balance then weighs the wet sample and holder and stores the result in memory. The traverse mechanism moves the sample and holder forward (to the left) until the oven bottom plate is reached. The traverse will then stop and the oven bottom plate is raised. The lift stops when the sample is tightly sandwiched between the top and bottom sprung-loaded plates. The sample will stay in this position for the time set on the rotary switch. This time will vary from 3 to 40 minutes, but the user can select other times.
The pump is switched on when the sample reaches the heating area and switched
off after all heating is finished. At this time, the bottom plate will
be lowered till the sample holder and sample are level with the traverse
path. The lift drive will stop and the traverse will go in reverse (to
the right) until the sample is positioned over the balance pan. The sample
will be weighed again and the percent moisture reported on the display.
If a repeat heating is required, say for high moisture samples, the operator
can re-introduce the sample by pressing the repeat button. (This can be
done as many times as required.) If another sample is to be run, the last
sample is removed, a new sample is placed on the pan and the lid closed again.
This process can continue indefinitely.
COMMENTS FROM CUSTOMERS
"We got it out the the box and running the day after we received it. Kinda like Christmas for a fire ecologist. Works like a dream." - Dr. Brian Oswald - Stephen F Austin State University, TX, USA
"We really enjoy the quickness and ease of testing now." - Dennis Childress - Orange County Fire Authority, CA, USA
SPECIFICATIONS AND FEATURES
WEIGHT: 12 Kgm
SIZE: 550mm x 220mm x 220mm (WxDxH)
POWER: 12-14 volts DC, 200 watts
CLEANING: The meter has easily removable sections to facilitate any cleaning.
PREPARATION: The sample is prepared by cutting it into small (1 cm square) and placing it between stainless steel gauze mats mounted on the aluminium rings.
RANGE: 1% to 1000% (Dry weight)
ALARMS: Battery low condition (meter is disabled on
battery low condition)
Oven temperature faults
BALANCE: Sartorius model BL150, 0-150 grams, 0.01 grams resolution. It is ruggedly mounted to prevent damage and ensure stable operation.
WIND: The sample area is fully enclosed to prevent errors in readings due to wind.
DISPLAY: The display gives messages indicating progress of measurement, error messages and results. It is 16 characters by 1 line.
MEMORY: The meter will store 254 readings that can be down loaded through a RS232 interface at a later date. The loaded results can also be viewed at any time.
MODES: Automatic(fully-automatic and semi-automatic), Manual(service), View memory data, RS232 operation.
SWITCHES: Repeat/select - used for repeat measurements and selection
Reset - used to reset the meter to the initial conditions in the event of an error.
Up/Down - used to view a function or to view data.
Start - used to start a new measurement.
Rotary - used to select 1 of 16 different heat times.
OVEN: The oven temperature is at 140 degrees Centigrade. This is not adjustable by the operator. The user can start operations at 120 degrees when the READY message appears. From cold it takes about 5-8 minutes to get to READY.
CYCLE: 1 minutes to 60 minutes cycle times (standard), user may select other times - 16 different settings.
Battery Eliminator for operation when not in the field
Rangelands calculations output.
GPS/Barcode label printer.
Department of Conservation & Land Management - Western Australia, Australia
Department of Conservation and Natural Resources - Victoria, Australia
CSIRO - Forest Research - Australian Capital Territory, Australia
US Forest Service - USA
Forest Service - Argentina
Parks Canada - Alberta, Canada
Resource Development, Canada
USAF Vandenberg AFB, USA
US Forest Service - San Dimas Technology & Development Centre -California, USA
CDF - California, USA
US Fish & Wildlife Service, USA
Bureau Of Indian Affairs, Arizona, USA
National Park Service, USA
Bureau of Land Management USA
Monitoring Group, University of Freiberg, Germany
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