Labconco Rapid Digestors User Manual
RAPID DIGESTORS
Model 23012 Rapid Digestor-25 without digestion tubes
Model 23080 Rapid Digestor - 4 without digestion tubes
INSTRUCTION MANUAL
Product designs are subject to change without notice
© 1998 Labconco Corporation
Form 23058 REV H / ECO A652
Printed in U.S.A
TABLE OF CONTENTS
Preface 4
General Description 5
Detailed Operational Function 5
Digestion Unit 5
Control Unit 6
Digestion Tubes, Flask Rack, and Retainer Plate 6
End Plates 7
Fume Removal System (Optional Equipment) 7
Specifications Digestor 25 - Place 8
Specifications Digestor 4 – Place 9
Installation 10
Unpacking 10
Operation & General Kjeldah Digestion Procedure 11
General Digestion for Feed, Grain 11
Routine Maintenance 13
Calibration 13
Troubleshooting 14
Service
Main Power Switch Replacement 15
Strip Heater Replacement 15
Indicator Lamp Replacement 15
Resistor Replacement 16
Ceramic Heater Replacement 16
Sensor Replacement 16
Parts and Service 17
References 18
Replacement Parts 19
Wiring Diagrams 21
Warranty 29
Shipping Claims 30
Contacting Labconco 31
PREFACE
Thank you for displaying confidence in us by selecting a Labconco Rapid Digestor. Our
design engineers, assemblers and inspectors have utilized their skills and years of
experience to ensure that the new Labconco Rapid Digestors meets our high standards of
quality and performance.
IMPORTANT NOTICE
This manual should be read carefully by all the end users in order to become familiar
with the operation of the Rapid Digestors. Recommendations are made within the
manual to help you obtain maximum performance and life from your product.
We have included sections on initial set up, operation, maintenance and troubleshooting
to provide you with all the tools necessary to achieve maximum performance.
If you have questions or concerns, do not hesitate to call us at 1-800-821-5525 for
assistance.
WARNING: THE DISPOSAL OF SUBSTANCES USED IN CONNECTION
WITH THIS EQUIPMENT MAY BE GOVERNED BY VARIOUS FEDERAL,
STATE OR LOCAL REGULATIONS. ALL USERS OF THIS EQUIPMENT ARE
URGED TO BECOME FAMILIAR WITH ANY REGULATIONS THAT APPLY
IN THE USERS AREA CONCERNING THE DUMPING OF WASTE
MATERIALS IN OR UPON WATER, LAND OR AIR AND TO COMPLY WITH
SUCH REGULATIONS.
4
INTRODUCTION
General Description
The Rapid Digestors are designed for wet digestions on material such as feeds, grains,
soils, plant tissues, water effluent, organic wastes, and food products. These digestions
are made prior to analysis for nitrogen, calcium, phosphorus, heavy metals, micronutrients, and other materials. The system consists of a control unit, a heating unit with
digestion tubes, and a flask rack for transporting tubes. The flask rack is equipped with
removable side panels providing increased heat transfer to the upper part of the digestion
tubes.
The heating unit consists of individual heaters constructed of ceramic materials providing
uniform and efficient heat transfer to the digestion tubes. The heaters are encased with an
efficient insulating material on four sides and the bottom to prevent heat loss, assuring
low energy consumption and safe casing temperatures. The close tolerance fit between
the inner ceramic tube and the digestion solution provides for shorter digestion times and
uniform digestion temperatures of the sample solution. The heating unit is enclosed in a
chemically etched aluminum casing, assuring easily cleaned surfaces with no paint to
flake off and providing a good appearance throughout the unit’s lifetime.
The control unit is of solid state design and regulates the temperature of the individual
heaters uniformly and accurately. The large temperature set point dial assures accurate
and repeatable temperature settings. The unique light display located on the heating unit
assures accurate temperature setting and allows for visual observation of the Digestor’s
operation.
The digestion tubes are thick-walled, rimmed, and made of borosilicate glass. Each tube
is manufactured to close tolerances to assure efficient and uniform digestions. Digestion
tubes are of the straight non-constricted type of approximately 250-ml capacity or with
construction and an accurate volumetric mark placed at 250-ml volume.
Detailed Operational Function
The Labconco Digestor consists of the digestion unit, the control unit, and accessories
(digestion tubes, flask rack, end plates, and retainer plate). The digestor can
simultaneously handle up to 25 samples, each weighing up to 5 g for solid materials or
approximately 25 ml for liquid samples.
Digestion Unit
The digestion unit contains electrically heated ceramic cores retained in a pan insulated
from the aluminum casing to reduce heat loss and to prevent the metal casing from
becoming hot. The ceramic cores are precision molded to accommodate the digestion
tubes and provide maximum direct contact with the tubes.
The center heating element with the 25-Place, or the rear left with the 4-Place, contains a
RTD platinum sensor that is encased in ceramic to sense the temperature of the digestor
and signals the control unit providing uniform temperature control.
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INTRODUCTION
CAUTION: The top surface of the digestor is hot during operation and for a period of
time after shutdown. To avoid the possibility of burns, do not touch the surface with bare
hands.
The exposed surfaces of the unit are made of aluminum finished by a chemically etched
process to withstand corrosion. The light(s) located on the front of the digestor indicates
when the digestor has reached set-point temperature and any malfunction that could
occur, along with providing over and under temperature set-point indications. Flashing
of the light(s) indicates proper temperature control.
Control Unit
The solid state proportional controller regulates the temperature of the digestor unit. The
Rapid Digestor-25 control unit is factory set to accept 208/240 volts, 50/60 Hz requiring
20 amp fusing and the 4-Place set to accept 115 volts, 50/60 Hz requiring 15 amp fusing.
Temperatures from a few degrees above ambient to 450° C can be set on the set point
indicator dial. Each controller is factory calibrated for proper temperature setting before
leaving the factory and should not require re-calibration. A calibration resister is
provided for a calibration check of the set-point temperature if required. (Refer to
Maintenance Section of manual for procedure). A red indicator light on the front panel of
the control unit is illuminated when unit is energized. Flashing of the light(s) located on
the digestor unit indicates the set-point temperature, when it has been reached, the
temperature of the digestor is proportionately controlled by the controller.
Digestion Tubes, Flask Rack, and Retainer Plate
Digestor Model 23006 is supplied with one set of thick-walled, heavy rimmed, heat
resistant glass digestion tubes with volumetric calibration marks at 250-ml volume.
Digestor Model 23000 is supplied with tubes having the same features as with Model
23006 except without calibration markings. Models 23012 and 23080 are supplied without digestion tubes. The heavy rims allow the tubes to hang in the stand when the rack is
lifted. The flask rack is constructed of aluminum alloy and holds the tubes during digestion as well as during cooling, dilution, washing, drying, and weighing of samples.
Samples are weighed or volumetrically delivered into the tubes and the digestion mixture
added. The tubes in the rack are then lowered into the digestor unit. The samples are
digested at the proper temperature for a predetermined amount of time. Digestion
temperature and time is determined by the type of sample being digested. After
digestion is complete, the flask rack containing digested samples must be removed from
digestor, cooled and diluted with water. The digestion is now complete and ready for
appropriate determination. The retainer plate (Rapid Digestor 25-Place only) is attached
to the digestor flask rack to lock the tubes in place, allowing the tubes to be emptied,
washed, and dried as a unit, without removal from the rack. The retainer plate is not to
be used during digestion, cooling or dilution of the samples.
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INTRODUCTION
End Plates
The end plates are rectangular aluminum plates that attach to the open ends of the flask
rack during digestion. Closing the open ends of the rack promotes proper refluxing to
wash down the sides of the tubes for complete and efficient digestions. The end plates
are removed during cooling, dilution and washing.
Fume Removal System (Optional equipment)
An optional fume removal system is available to provide removal of the corrosive fumes
expelled during a digestion. The use of this system is highly recommended to prevent
damage to conventional fume removal hoods.
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SPECIFICATIONS
Specifications (Rapid Digestor, 25-Place)
1.
Electrical
Operating Voltage: 208-240V AC single phase
Current (Max.): 16 Amp at 230V AC
Fusing: 25 Amp fuses @208 or 240V AC
operation
Frequency: 50 or 60 Hz
2.
Physical
Weight: Digestion Unit: 78 lbs.
Control Unit: 10.8 lbs.
Tubes: 9.2 lbs./set of 25
Flask Rack: 3.6 lbs.
End Plates: 1.4 lbs.
Size Digestion Unit: 8" H x 19-1/4"W x 19" D
Control Unit: 5-1/8"H x 8" W x 12-1/8"D
Flask Rack: 6-1/2"H x 14-1/4"W x 14-1/4"D
Flask Rack w/ handles 6-1/2"H x 17-3/4"W x 14-1/4"D
End Plate: 6-1/2"H x 14-9/16"W x 1"D
Tubes: Volumetric 11-15/16"L x 1.65 OD
Straight 11-15/16"L x 1.65 OD
Sample Size: Up to 5 grams
3.
Features
Digestion Tubes (Types) 250 ml straight
250 ml constricted with volumetric mark
Capacity
(samples/digestion)
Temperature range Ambient to 450°C
Heat-up time to 410°C Approximately one hour
Temperature readout Set point dial with indication lamps
25
8
SPECIFICATIONS
Specifications (Rapid Digestor 4-Place)
1.
Electrical
Operating voltage: 115V AC
Current (Max.): 6 Amp @ 115V AC
Fusing: 8 Amp @ 115V AC
Frequency: 50 or 60 Hz
2.
Physical
Weight (Shipping): 30 Lbs.
Size: Digestion Unit: 6-3/8"H x 9"W x 11-1/4"D
Control Unit 4-3/4"H x 6-3/4"W x 8-1/8"D
Sample size: Up to 5 grams
3.
Features
Digestion tube (types) 250 ml straight
250 ml constricted with volumetric mark
Capacity (samples/digestion) 4
Temperature range Ambient to 450°C
Heat-up time to 410°C Approximately 45 minutes
Temperature readout Set point dial with indication lamps
9
INSTALLATION
Unpacking
Use caution when unpacking the digestor and accessories to avoid damage. Remove the
digestor unit from the carton first and carefully inspect all packing material to insure that
no accessories or small parts are discarded by accident. If damage from shipping has
occurred, the customer must file a claim with the carrier IMMEDIATELY! Do not return
any item to Labconco Corporation without written authorization from the factory. Your
local laboratory apparatus dealer can assist you and should be contacted if problems
occur.
Installation
• Locate the digestor unit under a suitable fume removal system to assure complete
removal of fumes and vapors given off during the digestion.
CAUTION: Acid fumes given off during digestion are very corrosive. Digestion
unit must be placed in venting system that is totally resistant to acid fumes or
damage will result to the removal system. It is highly recommended that
Labconco’s fume removal system, designed for acid removal from digestors, be
used in conjunction with a laboratory fume hood.
• Locate control unit outside hood away from any vapors or fumes. Damage to control
unit will result if subjected to corrosive vapors or fumes.
• Connect power cord from control unit to digestor unit. Remove calibration resistor
from 2-pin connector located on rear of control unit. Connect small diameter gray
sensor cord to the 2-prong receptacle provided.
• Connect main power cord from control unit to suitable electrical outlet. (208-240V
AC 3-wire installation fused at 25 amps for the 25-Place digestor or 115V AC for the
4-Place. Refer to electrical specifications pages 5 & 6).
• Adjust temperature set-point dial to approximately 300°C. Turn switch to ON
position. Red pilot light on controller panel will be illuminated along with the red
light(s) on the Digestor’s front panel.
• Allow approximately 40 minutes for unit to reach temperature setting. When unit
reaches temperature, the light(s) on the digestor unit will flash. When light(s) are on,
one half of the time the temperature indicated on the temperature dial has been
reached.
• Place digestion tubes in flask rack. System is now ready for operation.
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