User’s Manual Hooded Combination (Macro) Kjeldahl Systems Models 21176 Series 21177 Series 21178 Series To receive important product updates, complete your product registration card online at register.labconco.com Labconco Corporation 8811 Prospect Avenue Kansas City, MO 64132-2696 800-821-5525, 816-333-8811 FAX 816-363-0130 E-MAIL labconco@labconco.com HOME PAGE www.labconco.com Please read the User’s Manual before operating the equipment.
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TABLE OF CONTENTS CHAPTER 1: INTRODUCTION Components Shipped General Description Performance Component Identification 1 1 2 3 3 CHAPTER 2: INSTALLATION General Installation Notes Location Bonnet Assembly Sash Assembly Electrical Connection Hood Exhaust System Hood Auxiliary System Electrical Tap Water Supply Distillation Manifold Acid Fume Blower Exhaust System Blower Airflow Exhaust Volume Requirement & Velocity Test Digestion Rack Drip Shield Sash Installation Glassware Installation 6 6 6 6 7 7 7 7 8 9
Chapter 1: Introduction Components Shipped Carefully check the contents of your Hooded Combination Kjeldahl System for shipping damage while it is still on the shipping plate. Do not discard the packaging material until the contents have been checked and the equipment has been approved for installation. The Hooded Combination Kjeldahl Nitrogen System has been shipped in one complete crate to minimize damage that may occur in transit.
Chapter 1: Introduction General Description Labconco’s Hooded Combination (Macro) Kjeldahl Nitrogen System is designed to facilitate the determination of Total Nitrogen content within materials such as feeds, grains, soils, fertilizers, plant tissue, water, organic wastes, and food products. The expression ‘Macro’ identifies the size of sample vessel and the sample size that can be used with this equipment.
Chapter 1: Introduction Performance The Hooded Combination Kjeldahl Digestion and Distillation Systems have been designed for use in the determination of nitrogen (or ammonia) concentrations. By calculation nitrogen can be converted to protein values for products such as plant tissues, meats and other food substances. Nitrogen determinations with the Hooded Combination (Macro) Kjeldahl Systems can accommodate sample sizes up to 5 grams due to the size of the digestion/distillation flasks.
Chapter 1: Introduction 3. Acid Fume Piping Exhaust System. Located on the left side of the unit, this exhaust piping removes excess sulfuric acid fumes from the digestion flasks. The Exhaust Piping must be connected to a remote blower to remove acid fumes.
Chapter 1: Introduction 5 6 3 3 1 4 2 Figure 1-2 Product Service 1-800-522-7658 5
Chapter 2: Installation General Installation Notes The Hooded Combination Macro-Kjeldahl System is shipped in two sections. The top exhaust bonnet and glass sashes will need to be installed after the main body has been installed in its final location. Exhaust duct work, electrical service, water supply and drain connections should be completed by a licensed contractor. The customer will need to purchase their preferred size of Kjeldahl Flasks, with one-hole-rubber-stoppers and distillate receiving flasks.
Chapter 2: Installation Sash Assembly The glass sashes are packaged separately and are installed into the hood assembly, by inserting the upper edge into its track first and then positioning the lower edge over the nylon runners in the lower sash track. See Figure 1-2 and Figure 2-8 for illustration of glass sashes.
Chapter 2: Installation Electrical Hooded Combination Macro-Kjeldahl Systems have been wired at the factory per the product model number ordered by the customer. Labconco model numbers ending in -11 are 115 volts. Model number ending in -12 are 230 volts. Models ending in -13 are 230 volt, three phase. Amperage requirements vary depending on the number of heaters per the digestion rack.
Chapter 2: Installation Tap Water Supply NOTE: ALL PLUMBING CONNECTIONS AND COMPONENTS MUST BE FREE OF FOREIGN MATERIAL BEFORE FINAL CONNECTIONS ARE MADE. Distillation Manifold The Hooded Combination Macro-Kjeldahl Systems feature an upper distillation rack with individual condensation columns, these are connected together by a common manifold (6 columns per manifold).
Chapter 2: Installation Acid Fume Blower Exhaust System The exhaust duct connection on top of the blower is sized for use with 6" nominal (6-5/8" O.D.) vent duct. The exhaust piping assembly is supplied with a short piece of 6" PVC pipe and a flexible coupling with clamps to connect to the dedicated duct work exhaust. The flexible coupling must be sealed air-tight to the exhaust duct work. All exhaust duct work must be acid-resistant and sealed air-tight. Use only acidresistant sealant on duct work joints.
Chapter 2: Installation (Duct Area in Square Feet) x (Average Airflow Velocity in feet per minute) = (Air Volume CFM) (Pi) x (radius²) x (117 FPM) = 25 CFM The exhaust stack rising from the piping assembly must be vented to the outside atmosphere via acid-resistant, sealed duct work and a remote blower (not included). If the remote blower pulls more than 25 CFM at the measurement point (48” above flexible coupling), close the damper shown in Fig. 2-6 to reduce airflow to the recommended 25 CFM.
Chapter 2: Installation Sash Installation Figure 2-8 12 Product Service 1-800-522-7658
Chapter 2: Installation Glassware Installation Connecting Bulb Rubber Tubing Distillation Manifold Delivery Tube Distillation Flask Receiving Flask Figure 2-9 Product Service 1-800-522-7658 13
Chapter 3: Normal Operation & Routine Maintenance Normal Operation Start-Up 1. The KNA apparatus is designed for use with either 500 or 800-ml Kjeldahl Flasks. The digestion heaters are free to move forward or backward on the runway to accommodate either size flask. 2. Turn the heat controllers to the setting on both the Digester and Distillation racks if both racks will be used simultaneously. Wait approximately 5 to 10 minutes to insure proper preheating.
Chapter 3: Normal Operation & Routine Maintenance Clean-Up and Cosmetic Guidelines • • • • Keeping the Hooded Macro Kjeldahl System clean will preserve the appearance and improve life of the equipment. Access to the blower exhaust or water aspirator system is gained by removing the lower left front access panel, located below the electrical panel. The equipment can be kept clean by washing with a weak solution of sodium hydroxide and rinsing with clear water.
Chapter 3: Normal Operation & Routine Maintenance Drip Shield The drip shield is constructed of stainless steel and is resistant to most acid attack. Acid spills can however cause discoloration and eventual marring of the surface unless the following proper procedures are followed in their clean up. 1. Promptly wash down all major acid spills contained by the shield. 2. Periodically clean the stainless surface with any residential stainless steel sink cleaning compound. 3.
Appendix A: Replacement Parts Electrical Heaters and Motor/Blower Parts Part Number Description 1315400 1315500 2011500 2023200 2033100 2033200 2023100 2031800 1870200 1317100 2056600 2053000 1967000 2144600 1662200 2165800 1880128 Heater Control, Infinite (115Volts) Heater Control, Infinite (230Volts) Core Plate Casting, (package of 6) Heater Base Casting (electric or gas) Heater element, 115V, 600 W, (package of 6) Heater element, 230V, 600 W, (package of 6) Heater Top ceramic casting (electric or gas)
Appendix B: Dimensions & Airflow Requirements B-1 18 Product Service 1-800-522-7658
Appendix C: Total Kjeldahl Nitrogen Method Titrimetric Determination Various scientific associations offer approved Kjeldahl methods. These methods are available at their websites.
Appendix C: Total Kjeldahl Nitrogen Method distillate receiving vessels, such as 250 ml Erlenmeyer flasks. The equipment is available as a combined system, featuring both digestion and distillation apparatus. The preheated burners should bring 250 ml of water at 25° C to a rolling boil with in 5 minutes. Condensation columns should cool distillate to 75° F (23.8°C). 3.3. Titration Class A Burets, 25-50 ml. for dispensing Standardized Acid solution. 3.4. Analytical balance, sensitive to 0.0001grams. 4.
Appendix C: Total Kjeldahl Nitrogen Method lower the burner heat setting to prevent sample from foaming up into neck of flask. Once, the sample comes to a smooth rolling boil return heat setting to maximum. When digestion sample clears (no black specs with pale green tint color), continue to boil for an equal length of time as required to reach the clear point, (total time approx. 1 hr).
Appendix C: Total Kjeldahl Nitrogen Method 7. Titration 7.1. Depending on the samples expected nitrogen level and the sensitivity of the titration desired, select the appropriate standardized H2SO4 solution (0.02 or 0.10 normal). High or low nitrogen concentrations will require standardized H2SO4 solutions with stronger or weaker normalitys. Titrations should require at least 15 ml of titrant to be accurate. Fill a class A. buret to the zero line with the standardized H2SO4 solution.
Appendix C: Total Kjeldahl Nitrogen Method Distillation: Excess base is added to the digestion product to convert NH4 to NH3 as indicated in the following equation. The NH3 is recovered by distilling the reaction product. ammonium ammonia heat sulfate gas (NH4)2SO4 + 2NaOH → 2NH3 + Na2SO4 + 2H2O Titration quantifies the amount of ammonia in the receiving solution. The amount of nitrogen in a sample can be calculated from the quantified amount of ammonia ion in the receiving solution.
