Buchi KjelMaster K-375 Operation Manual
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Buchi KjelMaster K-375 Operation Manual

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KjelMaster K-375 with KjelSampler K-376 / K-377
Operation Manual

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Summary of Contents for Buchi KjelMaster K-375

  • Page 1 KjelMaster K-375 with KjelSampler K-376 / K-377 Operation Manual...
  • Page 2 E-Mail: quality@buchi.com BUCHI reserves the right to make changes to the manual as deemed necessary in the light of experience; espe- cially in respect to structure, illustrations and technical detail. This manual is copyright. Information from it may not be reproduced, distributed, or used for competitive purpos- es, nor made available to third parties.
  • Page 3 Document History Index Date Author Changes 25/MAY/2012 NAGG Initial version 16/JUL/2013 NAGG First revised version 17/NOV/2014 HILS/BRUS Second revised version (update colorimetric titration) 28/APR/2016 HILS Removal of Declaration of Conformity 12/DEC/2018 HOES Third revised version (update colorimetric titration)
  • Page 4 Store the manual in the immediate vicinity of the instrument, so that it can be consulted at any time. No technical modifications may be made to the device without the prior written agreement of BUCHI. Unauthorized modifications may affect the system safety or result in accidents.

  • Page 5: Table Of Contents

    Operation Manuals for K-375 3.1.5 Optional accessories K-375 3.1.6 Optional accessories K-376 / K-377 Technical data overview 3.2.1 Technical data KjelMaster K-375 and KjelSampler K-376 / K-377 3.2.2 Technical data titrator Determination parameters Information on type plate 3.4.1 Titrator module and dosing unit 3.4.2...
  • Page 6 4.11 Explanation of alkaline direct distillation Putting into operation Installation site Electrical connections 5.2.1 Connections of the KjelMaster K-375 5.2.2 Connections of the K-376 / K-377 Transfer connection K-376 / K-377 to K-375 5.3.1 Connecting the K-376 to the K-375 5.3.2...
  • Page 7 Table of contents 6.2.3 System status icons User concept Editable and non-editable menu items The status view 6.5.1 RESULT display 6.5.2 CHART display Determination 6.6.1 System Preparation Single Sample 6.6.3 Sample Lists 6.6.4 Sequences Results 6.7.1 Result groups 6.7.2 Last Results 6.7.3 Blank Correction Determination Parameters...
  • Page 8 Table of contents 7.3.5 Inspecting the sample tubes Half-yearly maintenance 7.4.1 K-375 Sealing between sample tube and splash protector 7.4.2 K-376 / K-377 dip tube and sealing cap 7.4.3 Replacing the splash protector Yearly maintenance 7.5.1 Replacement of wear parts 7.5.2 Decalcification of the steam generator 7.5.3...

  • Page 9: About This Manual

    1 About this manual About this manual This manual describes the KjelMaster System K-375 / K-376 / K-377 and provides all information required for its safe operation and to maintain it in good working order. It is addressed to laboratory personnel in particular. NOTE The symbols pertaining to safety (DANGER, CAUTION and WARNING) are explained in chapter 2.

  • Page 10: Safety

    The present Operation Manual serves as the basis for this. Proper use The device has been designed and built for laboratories. It serves for nitrogen determination according to Kjeldahl. The KjelMaster K-375 as stand-alone device may also be used for distillations of steam-volatile substances. Improper use Applications not mentioned above are improper.

  • Page 11: Safety Warnings And Safety Signs Used In This Manual

    2 Safety Safety warnings and safety signs used in this manual DANGER, WARNING, CAUTION and NOTICE are standardized signal words for identifying levels of hazard seriousness of risks related to personal injury and property damage. All signal words, which are related to personal injury are accompanied by the general safety sign. For your safety it is important to read and fully understand the table below with the different signal words and their definitions! Sign Signal word...

  • Page 12: Product Safety

    2 Safety Symbol Meaning Symbol Meaning Device damage Hot surface Hand bruising Magnet Mandatory safety symbols Symbol Meaning Symbol Meaning Wear protective goggles Wear protective clothes Wear protective gloves Heavy load, lift with assistance Additional user information Paragraphs starting with NOTE transport helpful information for working with the device / software or its supplementaries.

  • Page 13: Instrument-Related Hazards

    2 Safety Danger Death or serious injuries by use in explosive environments. ∙ Do not store or operate the device in explosive environments. ∙ Remove all sources of flammable vapors. ∙ Do not store chemicals in the vicinity of the device. Caution Risk of minor or moderate cuts by sharp edges.

  • Page 14: Other Hazards

    2 Safety DANGER Risk of chemical burns by corrosives. ∙ Wear laboratory coat, protective gloves and protective goggles at all times. DANGER Risk of chemical burns by corrosives. ∙ During operation the sample tube contains either strong acid or strong base. In case the sample tube brakes, the content of the sample tube is collected in the drip tray on the bottom of the housing.

  • Page 15: Built-In Safety Elements And Measures

    2 5 5 Built-in safety elements and measures The KjelMaster K-375 has monitored protective doors which prevent a distillation to start while a door is open. A running distillation is immediately interrupted when a door is opened. The dosing of reagents is also immediately stopped.

  • Page 16: General Safety Rules

    Modifications to the device are only permitted after prior consultation and with the written approval of the manufacturer. Modifications and upgrades shall only be carried out by an authorized BUCHI technical engineer. The manufacturer will decline any claim resulting from unauthorized modifications.

  • Page 17: Technical Data

    This chapter introduces the reader to the device specifications. It contains the scope of delivery, tech- nical data, requirements and performance data. Scope of delivery 3 1 1 Basic devices KjelMaster K-375 Order number KjelMaster K-375 113751700 with glass splash protector and potentiometric sensor (220 –...
  • Page 18 2 Safety KjelMaster System K-375 / K-376 Order number KjelMaster System K-375 / K-376 113751710 K-375 with glass splash protector and potentiometric sensor K-375: 220 – 240 V, 50/60 Hz K-376 / K-377: 100 – 240 V, 50/60 Hz KjelMaster System K-375 / K-376 113752710 K-375 with glass splash protector and colorimetric sensor...

  • Page 19: Standard Accessories For

    3 Technical data 3 1 2 Standard accessories for K-375 Description Order number Picture Sample tube (300 mL) — Pair of glass tongs 002004 Connection cable RJ45 length 2 m 044989 Mains cable of the following types Type CH 010010 Type Schuko/Japan 010016 Type GB...
  • Page 20 3 Technical data Description Order number Picture FEP tube, 1.2 m, to driving motor 11056837 Capacitive level sensor for chemical or waste tank 11055914 Laboratory vessel 053203 Driving motor for dosing unit 11056835 Dosing unit (20 mL) 11056836 Test gauge sample tube holder 11059802 Tank 10 L 043410...

  • Page 21: Standard Accessories For K-376 / K-377

    3 Technical data 3 1 3 Standard accessories for K-376 / K-377 Description Order number Picture K-376 / K-377 cable RS232 (crossed) 043920 Sample tube 500 mL 026128 Clamp ring 043238 Hose clamp 022352 Fastener for transfer tube (K-376 only) 043482 Sample tubes (set of 4), 300 mL 037377 Express rack, 4 places (K-376 only)

  • Page 22: Operation Manuals For

    Operation Manuals for K-375 Description Order number English 11593514 German 11593515 French 11593516 Italian 11593517 Spanish 11593518 Chinese 11593519 Japanese 11593520 Russian 11593653 KjelMaster K-375 Network Connection 11593539 KjelMaster K-375 - Data Export 11593558 K-375 / K-376 / K-377 Operation Manual, Version E...

  • Page 23: Optional Accessories K-375

    3 Technical data 3 1 5 Optional accessories K-375 Description Order number Picture Sample tubes (set of 4) 100 mL 11057442 Sample tubes (set of 4) 300 mL 037377 Sample tubes (set of 20) 300 mL 11059690 Sample tubes (set of 4) graduated 300 mL 043049 Sample tubes (set of 4), 500 mL 043982...
  • Page 24 3 Technical data K-375 / K-376 / K-377 Operation Manual, Version E...

  • Page 25: Optional Accessories

    3 Technical data 3 1 6 Optional accessories K-376 / K-377 Description Order number Picture Stand for rack 11058659 Rack for 12 sample tubes, 500 mL 043970 Retainer plate (holds tubes firmly in rack for machine 038559 washing) Set of 10 boiling rods for digestion of samples with 043087 tendency of boiling retardation (alternative for boiling chips) Dip tube with cross-slot for soil/stone containing samples...

  • Page 26: Technical Data Overview

    3 Technical data Technical data overview 3 2 1 Technical data KjelMaster K-375 and KjelSampler K-376 / K-377 KjelMaster K-375 KjelSampler K-376 KjelSampler K-377 Connection voltage 220 – 240 VAC 100 – 240 VAC 100 – 240 VAC ±10 % ±10 % ±10 %...

  • Page 27: Technical Data Titrator

    3 Technical data > 99.5 % (1 – 200 Recovery rate mg N) < 1 % Reproducibility (RSD) Measuring range 0.02 – 200 mg N Environmental conditions for indoor use only Tempera- + 5 °C to + 40 °C ture up to 2000 m above sea level Altitude maximum relative humidity 80 % for temperatures up to 31 °C, decreasing Humidity...

  • Page 28: Determination Parameters

    3 Technical data T [°C] –30…115 0,5 K ±1 digit *Accuracy: Indicated in terms of measuring incertainty with a confidence of 95 %. In addition the measuring uncertainty of the sensor has to be taken into account as well. For pH electrodes e.g.: ∆ pH=0.012...0.03 according to DIN 19 266, Part 3.

  • Page 29: Information On Type Plate

    3 Technical data Information on type plate Device type code Serial number Supply voltage range/type Frequency of supply voltage Nominal power rating Year of manufacture Materials used 3 4 1 Titrator module and dosing unit part Material designation Housing sheet steel Note For the materials of the Dosing Unit, please refer to its manual which is delivered together with dosing unit.

  • Page 30: Material On The

    3 Technical data 3 4 3 Material on the K-376 / K-377 Part Material Material code Housing (mounting plate) Steel sheet St 12 ZE 1.0330 Housing (casing-below) Stainless steel 1.4301 (L 314) Housing (top cover) Alu-sheet AlMgSi1 Guide express rack Coating Polyester/Epoxy PEP 31...

  • Page 31: Description Of Function

    This chapter explains the basic principle of the instrument, shows how it is structured and gives a functional description of the assemblies. The KjelMaster K-375 is dedicated to Kjeldahl and Devarda nitrogen deter mination including potentio- metric or colorimetric titration.

  • Page 32: Opening The Service Door

    3 Technical data 4 1 1 Opening the service door The service door is secured with a sensor/switch: Electrical power is disconnected immediately when the service door is opened, thus preventing electrical shock during maintenance. To open the the service door for maintenance proceed as follows: To open the service door, ∙...

  • Page 33: Functional Principle Of Kjelmaster System

    4 Description of function Functional principle of KjelMaster System K-375 / K-376 / K-377 K-376 / K-377 K-375 Sample tube Dip tube Splash protector Steam generator Condenser Distillate outlet tube Receiving vessel Fig. 4.3: Functional principle of the K-375 with K-376 or K-377 The sampler arm with dip tube is positioned in a sample tube in the K-376 / K-377.
  • Page 34 4 Description of function Fig. 4.4: Sample transfer principle Fig. 4.5: Steam transfer during distillation K-375 / K-376 / K-377 Operation Manual, Version E...

  • Page 35: Standby Function

    4 Description of function Standby function Press the key READY to start heating the steam generator. Press the key STANDBY to stop heating the steam generator. Fig. 4.6: Status view After 30 minutes without operation, the heating of the steam generator is automatically turned off. In this case „Standby“...

  • Page 36: Distillation And Titration

    The built-in titrator is fully controlled via the K-375 software. It is not possible to use the titrator without the KjelMaster K-375. It can be used for boric acid or back titration. The measuring mode can be determined as endpoint or startpoint titration by defining the method in the K-375. The software of the K-375 allows to choose between standard and online titration.

  • Page 37: Titration Mode

    4 Description of function with the measurement. Colorimetric titration requires daily determination of the setpoint. 4 5 5 Titration Mode Standard In the standard mode the distillation and titration are performed sequentially. First the distillation is completed then the titration starts. Online In the online mode the titration starts while the distillation is still in progress.

  • Page 38: Different Methods

    4 Description of function Different methods BUCHI standard methods are stored in the instrument. All BUCHI methods are “read only“, but it is possible to copy and save them under a different name as an editable customer method. All methods are listed in alphabetical order, customer methods are first, followed by the “read only”...

  • Page 39: Control Blanks

    4 Description of function 4 7 2 Control blanks A control blank enables to check for cross contamination, e.g. in the middle of a rack, without affecting the calculation of the following samples. Example: Determination of 3 blanks, 6 samples, 1 control blank, 10 samples in a 20-position rack. All samples are calculated with the mean value of blank 1-3.

  • Page 40: Indicator For Colorimetric Titration

    Even the slightest changes to the ratio can result in incorrect end point determination. As an alterna- tive, methyl red/bromocresol green mix indicator can also be used. Ready-made, premixed boric acid solutions for both indicator options can be obtained from Buchi. 4.10 Result Groups Each result of a sample determination can be assigned to a group, e.g.

  • Page 41: Explanation Of Alkaline Direct Distillation

    For details on the application procedure, please contact your local BUCHI representative. Determination of the conversion factor and the regression factor: Fig. 4.8: Example of factor calculation...
  • Page 42 4 Description of function Factors of above Example Conversion Factor = 0.7787; Regression Factor = -0.055. NOTE Milk samples with a reduced protein content are obtained by dilution with distilled water. Calculation: Calculation of the protein content after factor determination. g protein/100 mL = (V )xConv.

  • Page 43: Putting Into Operation

    30 cm. No containers, chemicals or other objects must be located behind the instru- ment. The KjelSampler K-376 or K-377 is set-up on the left side of the KjelMaster K-375 with a space of approximate 10 cm. Make sure that the back of the KjelSampler is not in contact with anything, e.g.

  • Page 44: Electrical Connections

    4 Description of function Electrical connections 5 2 1 Connections of the KjelMaster K-375 a Power connection K-375 h Fuses (2 x 10A) b RS232 connection to K-376 / i Connector for dosing unit (Acid) K-377 j Connector for additional dosing unit (Base)

  • Page 45: Connections Of The

    5 Putting into operation ∙ Connect the power cable to the power connection ∙ Connect the level sensors to the corresponding connectors NOTE Unlike the level sensors for the storage tanks of H 0, NaOH and H , the presence of the level sensors for the waste containers has to be indicated within the software! (See section “Peripherals”...

  • Page 46: Transfer Connection K-376 / K-377 To

    5 Putting into operation Transfer connection K-376 / K-377 to K-375 The transfer connection between the K-375 and the K-376 or K-377 sampler consists of two hoses, the white transfer hose and the red steam hose. Both hoses have to be connected to the K-375 as well as to the sampler (K-376 or K-377) and secured with hose clamps.
  • Page 47 5 Putting into operation Fixing the transfer hose to the K-375 Mount the white transfer hose on the valve of the K-375 (top right corner): ∙ Unscrew the screw cap from the screw connection of the valve (attention: 2 parts) and take out the cutting ring ∙...

  • Page 48: Connecting The Transfer Hoses Of The

    5 Putting into operation Connect the K-375 and the K-376 / K-377 with the corresponding/delivered RS232 cable (crossed) ∙ K-375: See b in picture 5.1 ∙ K-376 / K-377: see d in picture 5.2 WARNING Risk of burns by hot steam. ∙...

  • Page 49: Reagent/Water And Waste Connections

    5 Putting into operation On the K-375 ∙ Remove the tightening screw from the holder on the valve 1. (The screw is not required for connection to K-377) ∙ Slide the ring of the chain fastener onto the holder on the valve 1 and fix it by tightening the threaded bar.
  • Page 50 5 Putting into operation O pump (for steam generator and sample d Waste outlet (receiver waste) tube) e Waste outlet (sample tube waste) b Boric acid (H ) pump f Cooling water outlet c NaOH pump g Cooling water inlet Fig.

  • Page 51: Buret Unit For Titrant

    5 Putting into operation Waste/aspiration hoses The sample residue can be aspirated and collected separately from the receiver waste. For this purpose a separate collection tank is necessary. For joint disposal of the sample tube and the receiver waste the delivered y-piece is used to guide the two hoses into one hose.
  • Page 52 5 Putting into operation The bottle containing the titration solution can be fixed on the right side of the device using the provided strap The buret (consisting of the dosing unit and the corresponding drive unit) is mounted on the bottle. Fig.

  • Page 53: Positioning Of The Dosing Tip

    5 Putting into operation Positioning of the dosing tip Mount the spacer onto the titrant dosing tip to adjust the positioning of the outlet and place it in the receiving vessel. It should be positioned in the same height as the stirrer. Fig.

  • Page 54: Level Sensors

    5 Putting into operation NOTICE Risk of device damage by calciferous water or wrong rong connected tanks. ∙ Use only distilled water for the H O storage tank to keep the steam generator maintenance-free. ∙ Make sure that the tanks are connected correctly. If the wrong tank (e. g. reagent tank containing NaOH) is connected to the pump labelled as „H O“, the steam generator will get damaged.
  • Page 55 5 Putting into operation ∙ The red LED at the sensor should now be off. ∙ If the sensor does not safely detect the liquid: Use a small screwdriver to set the sensitivity (with the small adjustment screw) of the sensor (see in figure 5.9).

  • Page 56: Installation Of The Titration Sensor

    (Sher: 610nm, bromocresol/methyl red: 640nm); this can be done with a permanent magnet (magnetic mixing rod) on the sensor probe. Clean the optical sensor before use and construct the test setup according to the technical note (335/2018) available on the BUCHI website.

  • Page 57: 5.10 Connections To Peripheral Devices

    Manual - Network Connection, which can be obtained from any authorized BUCHI representative. 5 10 3 Connecting a KjelSampler K-376 or K-377 Connect the KjelSampler K-376 or K-377 to the KjelMaster K-375 by means of the supplied RS232 cable. 5 10 4...

  • Page 58: Connecting A Bar Code Reader

    5 Putting into operation 5 10 5 Connecting a bar code reader A USB barcode reader can be used to read in data, e.g. a sample name or the weight of a sample, that is printed in form of a barcode. The barcode reader can be connected to the corresponding USB connector on the rear side of the K-375.

  • Page 59: Preparing The Hardware

    5 Putting into operation Depending on your preferred applications and methods the following items have to be defined: Volumetric solutions HOME  Volumetric Solutions Define all solutions that may be used for your applications. Reference substances (optional) HOME  Reference Substances Specify the reference substances together with their theoretical values.

  • Page 60: Operation

    5 Putting into operation Operation This chapter gives examples of typical device applications and instructions on how to operate the device properly and safely. CAUTION Risk of injury. Never operate the device with damaged glassware. The operating principle The graphical user interface of the K-375 is operated via the touch screen. To select a button or an input element in the dialog window, you simply touch the screen using a soft blunt object or a fingertip.
  • Page 61 5 Putting into operation Determination System Preparation Perform all tasks related to the preparation of the and manual opera- system, like Preheating, Priming, Cleaning, Aspiration, All tasks tion periodic tasks like electrode calibration or manual related to tasks related to burets, pumps, and a sampler. the sample Single Sample Determine a single sample based on Type, Name,...

  • Page 62: The Title Bar

    6 Operation 6 2 1 The title bar The title bar is present on top of any screen and consists of the following components: Fig. 6.2 Title bar Icon of the current dialog Title of the current dialog System status icon Options, hints or help for the current screen Date &...

  • Page 63: System Status Icons

    NOTE In case you forgot the password for your administrator account, you can ask your BUCHI service center for a password for the BUCHI Administrator. The account of the BUCHI administrator will always be present on your system and can not be deleted. The password will be valid for one day, enabling the creation of a new administrator account on your system.
  • Page 64 6 Operation further screens. In the example below the Titer is the only attribute that may be changed by an operator: Fig. 6.4 Volumetric solutions screen If an item is editable or not, depends on the rights of the user. All resources that are present by default (standard methods, volumetric solutions, and reference substances) can not be deleted –...

  • Page 65: The Status View

    6 Operation The status view The status view of the system is accessible via the SHOW/HIDE STATUS button in the bottom bar: Fig. 6.6 The status view Buttons for direct dosing of boric acid, sodium hydroxide, and water. NOTE The dosed amount per click can be adapted by a user with administrator rights under HOME u SETTINGS u Dosage volume in status view Buttons for switching between RESULT-, CHART-, and INFO-display.

  • Page 66: Result Display

    6 Operation Colors of the status field Color of status field Meaning Green – the system is ready for sample determinations. Orange – the system is in standby mode. (The steam generator is powered off.) Blue – the system is busy (preparative task, periodic task, or sample determination running).

  • Page 67: Chart Display

    Determination In general there are three different ways for a sample determination with the KjelMaster K-375: ∙ Determination of single samples (one by one without a sampler) ∙ Determination of a predefined sample list (one by one without a sampler) ∙...
  • Page 68 6 Operation Single sample Sample List Sequences (automatic determination determination rack determination with sampler) Recom- ∙ Only few samples ∙ Many samples ∙ Determination with mended ∙ Express sample (> 10) digestion for: (e. g. interruption of a ∙ Routine analysis ∙...

  • Page 69: System Preparation

    6 Operation 6 6 1 System Preparation Within the area System Preparation all tasks related to the preparation of the system, like Preheating, Priming, Cleaning, and Aspiration can be defined and performed. In addition periodic tasks like elec- trode or pump calibration and certain manual tasks related to burets, a sampler, or pH measurement can be performed.
  • Page 70 Zero point pH 6.4 – 7.6 (For pH electrodes other than the ones supplied by BUCHI, additional criteria might be important.) NOTE It is recommended to use buffer solutions pH 4.00 and 7.00. (For a 3 point calibration in addition the buffer solution for pH 9.21 is recommended.)
  • Page 71 6 Operation Setpoint colorimetric sensor It is necessary to determine the Setpoint every day before starting sample determinations, and when the method is changed or fresh chemicals are used to adjust the device to the current conditions. Before the Setpoint determination a Preheating should be performed to heat up the system.
  • Page 72 6 Operation Preheating The glass parts of the distillation system have to be preheated prior to analysis. This is done by means of a clean and empty sample tube. It is recommended to perform a preheating, when the glassware has cooled down. A status message on the status view will inform the user if preheating is required.
  • Page 73 6 Operation Priming Priming is used to prepare the entire system. This preparation procedure includes the distillation and titration with a clean and empty sample tube, as well as the dosing of chemicals. It is recommended to perform a priming at least once a day, before starting analysis.
  • Page 74 6 Operation Cleaning With regular cleaning, the lifetime of the glass parts can be extended. Thus it is recommended to perform a few cleaning runs before switching off the unit. The cleaning procedure is performed by means of a distillation with water in a clean sample tube. Thus all residues from the last sample determination can be removed.
  • Page 75 6 Operation Buret functions Select the buret function to be performed: ∙ Prepare, ∙ Discharge, or ∙ Dose Press START to start the selected buret function. NOTE If more than one buret is connected to the instru- ment, the respective buret unit (Acid or Base) can also be selected.
  • Page 76 6 Operation Sampler functions The actions “Move to zero position” and “Move to service position” are available for both sampler types (1-tray and 2-tray). For a 2-tray sampler the arm is moved to the corresponding zero or service position of the tray, the arm is actually positioned in. For a 2-tray sampler it is also possible to move the arm of the sampler with “Move to tray A”...

  • Page 77: Single Sample

    6 Operation Single Sample In general four different kinds of samples can be determined: ∙ Blanks (can be used for the correction of sample results). ∙ Samples ∙ Reference substances (results can be rejected if a reference substance is outside of its predefined limits) ∙...
  • Page 78 6 Operation For samples of type Sample, press “Name” and enter a name for the sample result. Press “Sample weight” and enter the weight of the sample in [g] or [mL]. Press “Protein factor” and enter the protein factor for the determination of the results. Press “Method”...

  • Page 79: Sample Lists

    6 Operation For samples of type Control Blank, press “Name” and enter a name for the control blank result. Press “Method” and select the method to be used for the determination of the control blank from the list of the available methods. Press “Group”...
  • Page 80 6 Operation The Sample Lists screen shows a list of all present Sample Lists. New Sample Lists can be created with NEW and existing ones can be deleted, renamed or copied. It is also possible to import sample lists that have been set up on a personal computer from a USB device or a network place.
  • Page 81 6 Operation When adding a new sample, always a sample of the same type like the previously added sample is added automatically. All parameters of the newly added sample can be adapted. Using the buttons PREVIOUS/NEXT POSITION it is possible to navigate from one set of sample parameters to the parameters of the previous or following sample in the list.
  • Page 82 6 Operation According to the selected type of sample, a different set of parameters is offered. For samples of type Blank, press “Name” and enter a name for the blank result. Press “Method” and select the method to be used for the determination of the blank from the list of the available methods.
  • Page 83 6 Operation For samples of type Reference Substance, press “Name” and enter a name for the result of the reference substance determination. Press “Reference substance” and select the refer- ence substance from the list. Press “Sample weight” and enter the weight of the sample in [g] or [mL].

  • Page 84: Sequences

    6 Operation Using the BALANCE button the weight of samples can be taken over from a connected balance: Select all samples using the SELECT ALL ∙ button ∙ Press BALANCE – all blanks and control blanks are automatically deselected (no weight is needed for blanks) ∙...
  • Page 85 6 Operation Rack 20 Enter the samples for a 20 place rack. For a 2-tray sampler the tray position (A or B) can be selected using the SETTINGS button within the step. This step can be edited within the sequence. Pause The sequence is stopped until it is continued by pressing Start.
  • Page 86 6 Operation Press NEW to create a new sample sequence. After entering a unique name for the new sequence either a first single step, or a default set of the five commonly used steps can be added to the new sequence (press Add Defaults to add the default set of steps or select a single step from the list and press OK).
  • Page 87 6 Operation Click on the Rack step to adapt the settings of the rack and to add samples to the rack. Press SETTINGS and adapt the settings for the rack: “Determine blanks first” Yes/No (If blanks are determined first, the risk of a cross- contamination can be minimized for the blanks.) “Pause after blank calculation”...
  • Page 88 6 Operation The first parameter for each sample is the sample type: Blank, ∙ ∙ Sample, ∙ Reference substance or ∙ Control blank. Press NEW to enter a sample of the selected type on the next position without leaving the screen. With OK the sample is added to the actual position and the sample list is displayed again.
  • Page 89 6 Operation For samples of type Sample, press “Name” and enter a name for the sample result. Press “Sample weight” and enter the weight of the sample in [g] or [mL]. Press “Protein factor” and enter the protein factor for the determination of the results. NOTE Using a bar code reader it is also possible to read in every sample related data like name or weight...
  • Page 90 6 Operation For samples of type Control Blank, press “Name” and enter a name for the control blank result. Press “Method” and select the method to be used for the determination of the control blank from the list of the available methods. Press “Group”...
  • Page 91 6 Operation Using the BALANCE button the weight of samples can be taken over from a connected balance: ∙ Select all samples ∙ Press BALANCE – all blanks and control blanks are automatically deselected (no weight is needed for blanks) ∙...

  • Page 92: Results

    6 Operation Results In the result area all tasks related to the results (viewing, printing, and exporting) can be performed. 6 7 1 Result groups As the name implies, result groups are folders in which results can be stored and grouped in accor- dance with their properties.
  • Page 93 6 Operation  The content of selected groups or selected results can be printed (PRINT) or exported (EXPORT) to a memory stick or network folder. The path to the network folder and to the target directory on the memory stick can be defined under Settings  Import & Export (see chapter “6.9.1 Settings“). Just like the list of the result groups, also the list of the contained results can be filtered.

  • Page 94: Last Results

    6 Operation 6 7 2 Last Results The Last Results screen shows a list of the last 40 results of the system, regardless to the type of the results. The sample report of selected results can be printed either detailed or short. Results can be exported to a USB stick or a network place.

  • Page 95: Blank Correction

    6 Operation 6 7 3 Blank Correction The blank correction can be switched on and off: HOME  Blank Correction  SETTINGS Blank correction of results is switched on. OFF Blank correction of results is switched off – no blank correction at all will be performed. Within the Blank Correction main screen a list of the latest blanks can be viewed.
  • Page 96 6 Operation Within the settings for the blank correction, ∙ switch “Blank correction” ON switch “Auto blank generation” OFF ∙ ∙ select NO for “Use last measured blank” ∙ confirm your settings with OK. Press MANUAL Enter a name for the manual blank value. Enter the volume for the blank in [mL] Confirm your settings with OK.
  • Page 97 6 Operation Within the settings for the blank correction, switch “Blank correction” ON ∙ ∙ switch “Auto blank generation” OFF ∙ select NO for “Use last measured blank” ∙ confirm your settings with OK. Press MEAN Enter a name for the mean blank value. Check the check box of those measured blank values that shall be used for the calculation of the mean value.
  • Page 98 6 Operation Automatic Blank determination With automatic blank determination switched on, each continuous row of measured blanks is auto- matically averaged and the resulting mean value is used for the correction of the subsequently measured sample(s). After one or more samples have been determined, the next measured blank (or the mean of the next measured continuous row of blanks) will be used as active blank value for the correction of the subsequent samples until the next blank is determined.

  • Page 99: Determination Parameters

    6 Operation Determination Parameters Within this area, the methods for determinations with the K-375 can be written and the resources like reference substances or volumetric solutions for the titration can be defined and edited. (Once defined, the resources can be referenced from within the method.) 6 8 1 Methods The structure of the K-375 method is highly flexible and offers all possibilities to create a method that...
  • Page 100 6 Operation The different areas of the method are separated from each other by the corresponding heading. The Method Information section at the bottom of each method provides information about the last modifi- cation date and the creator of the method. K-375 / K-376 / K-377 Operation Manual, Version E...
  • Page 101 (The concentration of the sodium hydroxide solution doesn‘t need to be specified within the instrument. For BUCHI applica- tions a solution of 32 % NaOH is recommended.) A reaction time for the alkalization can be specified via the “Reaction time“...
  • Page 102 Depending on the application either a back titration or a boric acid titration can be performed. BUCHI recommends the use of the boric acid titration. If no titration at all shall be performed, None can be selected for the parameter “Titration type”. The boric acid titration can be performed either with a potentiometric or a colorimetric sensor –...
  • Page 103 6 Operation Parameters for Back titration (potentiometry only) Select Back titration for the parameter “Titration type“. For the back titration the ammonia is collected in a receiving solution of a strong acid. Afterwards the remaining amount of the acid, that has not been consumed for the neutralization of the ammonia, is titrated back with a strong base.
  • Page 104 6 Operation Parameters for Boric acid titration with colorimetric sensor Select Boric acid titration for the parameter “Titration type“. The volume of the boric acid to be dosed into the receiving vessel can be specified and the titration solution can be selected from the tritration solutions list (see chapter ”6.8.2 Volu- metric Solutions”).
  • Page 105 6 Operation Parameters for Boric acid titration with potentiometric sensor Select Boric acid titration for the parameter “Titration type“. The volume of the boric acid to be dosed into the receiving vessel can be specified and the titration solution can be selected from the Volumetric solutions list (see chapter ”6.8.2 Volumetric Solutions”).
  • Page 106 6 Operation Determination Parameters With the determination parameters the Determination mode (either “Standard” or “Direct distillation”) can be determined. In addition two sets of result units (each set consisting of one mass- and one volume-related unit) can be selected for the standard determination mode. Click on “Determination mode“...
  • Page 107 6 Operation Aspiration Parameters After a determination has been completed, the waste in the sample tube and/or in the receiving vessel can automatically be aspirated and transferred into a corresponding waste container: Click on “Aspiration sample tube“ and select Yes to switch on the automatic aspiration of the sample tube.

  • Page 108: Volumetric Solutions

    6 Operation 6 8 2 Volumetric Solutions All volumetric solutions that may be used for a titration can be defined in this menu. Once a solutions has been defined, it can directly be referenced and used from within a method. Create a new volumetric solution using a unique name, or delete or rename an existing one.

  • Page 109: Reference Substances

    6 Operation 6 8 3 Reference Substances If a reference substance and its theoretical value is defined, it is possible to automatically calculate the recovery rate. Limits for this recovery (lower and upper limit) can also be defined in a way that the system rejects results if they are outside of these limits.

  • Page 110: 9 Device

    6 Operation Device The Device area provides access to all tasks that are related to the device itself, like ∙ adapting the system settings, ∙ performing system diagnostics, ∙ using utilities, like database backup, and the lab timer ∙ Login/Logout to the instrument ∙...
  • Page 111 6 Operation Regional Settings Select your language from the offered range of 7 available languages: English, German, French, Spanish, Italian, Chinese and Japanese. Switch to your preferred keyboard layout, English, German or French. The Date format can be switched to “Month, Day, Year”, “Day, Month, Year”, or “Year, Month, Day”, with a slash, dot or hyphen as separator.
  • Page 112 6 Operation Result units Create a new unit with NEW and store it under a new, unique name. Select a base unit for the new unit calculation Selectable are: g N/L, % N, g Pr/L or % Pr (N = nitrogen content, Pr = protein content) Enter a correction factor and/or correction offset if necessary and select the preferred number of decimal places.
  • Page 113 6 Operation Peripherals Select Yes for all present peripherals: ∙ Level sensor for receiver waste container ∙ Level sensor for sample tube waste container ∙ Sampler ∙ Balance ∙ Chiller ∙ Printer NOTE Unlike the level sensors for the storage tanks of 0, NaOH and H , the level sensors for the waste containers have to be activated!
  • Page 114 NOTE More details regarding the network connection can be found in the document “Manual – Network connection K-375”, which can be obtained from any authorized BUCHI representative. K-375 / K-376 / K-377 Operation Manual, Version E...
  • Page 115 “User management” is active and the Logout functionality becomes visible on the home screen. As soon as a user account has been created the system automatically creates a default “BUCHI Administrator” account. This account can be used in case all users with own accounts forgot their passwords.
  • Page 116 6 Operation Three levels of user authorisation can be assigned: Administrator (not restricted) ∙ ∙ Operator (limited permissions) ∙ Lab Manager (limited permissions) See also section „6.3 User concept“. Device information Information about the hard- and software of the system can be viewed. No Settings can be changed.

  • Page 117: Utilities

    6 Operation 6 9 2 Utilities There are three different utilities contained in the device software: ∙ The Database management – backup and restore of the complete device data (settings, methods, resources, results etc.) The Lab timer – create a countdown timer ∙...

  • Page 118: 9 3 Diagnostics

    6 Operation Demo mode Select On to switch to the Demo mode and Off to leave the Demo mode. NOTE In demo mode no chemicals are used or dosed and determinations are only simulated. The demo mode is automatically deactivated as soon as the instrument is switched off.

  • Page 119: Logout

    6 Operation 6 9 4 Logout When clicking on Logout, the current user is automatically logged out and the Login screen is displayed. To login to the system, click on one of the present users and – if a password has been specified for this user –...

  • Page 120: Daily Maintenance

    All instructions aimed at maintaining the KjelMaster Systems (K-375 / K-376 or K-375 / K-377) respec- tively the KjelMaster K-375 (standalone) in good working condition are to be observed. This also includes periodic cleaning and checking for any possible damage.

  • Page 121: Before Sample Determination (Colorimetry)

    6 Operation 7 1 2 Before sample determination (colorimetry) ∙ Set up the receiving vessel as described in Section 5.9.2 ∙ Rinse the titration hoses (Path: System Preparation  Buret functions  Buret function “Dose”). ∙ Preheate the system (Path: System Preparation  Setpoint colorimetric sensor  Preheating before Setpoint), see also chapter “6.6.1 System Preparation”.

  • Page 122: After Sample Determination

    6 Operation 7 1 3 After sample determination Clean the system using the Cleaning procedure and/or manual cleaning. 7.1.3.1 Automatic cleaning procedure ∙ The software offers the possibility to add a cleaning step to each sequence for the sample determination with a sampler K-376 / K-377.

  • Page 123: (Potentiometry Only)

    95 – 105 % ∙ Zero point pH 6.4 – 7.6 For pH electrodes other than the ones supplied by BUCHI, additional criteria might be important. NOTE It is recommended to use buffer solutions pH 4.00 and 7.00. Discard buffer solutions after usage. Work with fresh solutions every day.

  • Page 124: Sample Tube Cleaning

    6 Operation ∙ If you choose “Add defaults” when creating a new sequence the dosing step is automati- cally added to the sequence. ∙ However, if you do not create a new sequence based on the default steps, the dosing step can be added to the sequence at any time using the NEW button.

  • Page 125: Weekly Maintenance

    6 Operation Fig. 7.2: Cleaning tubes in the rack NOTE To clean the tubes and rack together in the dishwasher additional accessories are required. ∙ Place the sample tubes and rack on the rack stand ∙ Install the retaining plate and lock it with the 2 latches to secure the sample tubes.

  • Page 126: Device Monitoring

    Drying before analyzing: 8 h at 105 °C Nitrogen content: w = 0.1866 (18.66 %) Original sample weight: 200 mg Kjeldahl catalyst: Titanium BUCHI Kjeldahl Tablets Catalyst amount: 2 tablets Sulfuric acid conc. 98 %: 15 mL Digestion temperature: see BUCHI Application Notes Digestion time:...

  • Page 127: Cleaning Colorimetric Sensor And Mesh

    7 Maintenance 7 2 6 Cleaning colorimetric sensor and mesh ∙ Rinse the sensor and the protection mesh thoroughly with distilled water ∙ Use only soft tissues to wipe the mirror surface and make sure no foreign material is on it, as this would involve the danger of the surface getting scratched ∙...
  • Page 128 7 Maintenance ∙ Transfer the dosed volume into a graduated cylinder, measure the volume and enter the measured volume in the “Calibration volume [mL]” screen. The value shown for “Calibration volume” is updated. NOTE Repeat this procedure until the entered and the dosed volume correspond. An acceptable difference at 50 mL is ±5 mL.

  • Page 129: Checking The Distillate Amount

    7 Maintenance 7 3 2 Checking the distillate amount ∙ Carry out preheating (three times) so that the system is warm before performing this test. ∙ Create a new method using the following parameters: O volume: 0 mL NaOH volume: 0 mL Reaction time: Distillation mode: Fixed time...

  • Page 130: Inspecting The Buret

    7 Maintenance 7 3 3 Inspecting the buret Inspect the attached buret(s) to recognize damages as early as possible. Carrying out a test according to EN ISO 8655, Part 3 and 6. 7 3 4 Inspecting the titrator Inspect the electrical contacts (plugs, stirrer) for corrosion and mechanical damage, if the titration unit is used in premises with an occasional occurrence of corrosive matters in the atmosphere.
  • Page 131 7 Maintenance Check all glass parts for scratches or chips NOTE Sample tubes with scratches or chips can break during determinations: Results Glass parts show no damage: The glass parts are O.K. Glass parts have scratches or chips Replace faulty glass parts. K-375 / K-376 / K-377 Operation Manual, Version E...

  • Page 132: Half-Yearly Maintenance

    7 Maintenance Half-yearly maintenance 7 4 1 K-375 Sealing between sample tube and splash protector We recommend to replace the rubber sealing on the splash protector (connection to the sample tube) every half year to avoid leakages. NOTICE Risk of device damage by overtightening the screw fitting. ∙...

  • Page 133: K-376 / K-377 Dip Tube And Sealing Cap

    7 Maintenance 7 4 2 K-376 / K-377 dip tube and sealing cap The sealing cap is an expendable part which needs to be replaced periodically. We recommend to replace this every half year according to the below instruction. During use the dip tube will change its color from white to grey.

  • Page 134: Replacing The Splash Protector

    7 Maintenance ∙ Pull the sealing cap out of the sampler arm from below. ∙ When inserting the new sealing cap from below take care to its orienta- tion – the two fittings on top are not arranged symmetrically. When the sealing cap is inserted properly, both fittings have to reach through the two corresponding holes in the sampler...
  • Page 135 7 Maintenance WARNING Death or serious injuries by contact with high voltage. ∙ Make sure device is switched off and unplugged before replacing the pump. Open the service door. ∙ Disconnect the water connection ∙ Disconnect the NaOH connection K-375 / K-376 / K-377 Operation Manual, Version E...

  • Page 136: Yearly Maintenance

    7 Maintenance ∙ Remove the sample tube and the dip tube ∙ Remove the screw cap with the sealing as described in section 7.4.1 ∙ Loosen the screw cap with the open end spanner (11058252) ann slide it back ∙ Loosen the two screws and take the holder away.

  • Page 137: Decalcification Of The Steam Generator

    7 Maintenance 7 5 2 Decalcification of the steam generator To decalcify the steam generator proceed as follows: ∙ Make sure that the steam generator is cooled down (switch off the unit and let it cool down for at least 30 minutes) ∙...

  • Page 138: Replacement Of The Wave Spring

    7 Maintenance ∙ Remove the two screws a on the rear side of the instrument. The posi- tion of the sodium hydroxide pump is marked on the housing with the imprinting “NaOH”. ∙ Open the service door. ∙ The sodium hydroxide pump is the lowermost of the three pumps situ- ated on the left side.

  • Page 139: Replace Every Two Years

    7 Maintenance NOTE Make sure that one of the clips of the holder presses on the spring inside the sampler arm. (See arrow in the figure beneath.) Otherwise the sample tube detection will not work! Replace every two years 7 6 1 Replacement of the transfer connection WARNING Serious chemical burns by corrosives.
  • Page 140 7 Maintenance ∙ Switch both devices (the KjelMaster and the KjelSampler) off. ∙ Wait until all parts of the devices have cooled down to room temperature. ∙ Loosen the connections of the transfer hose and the steam hose on the rear side of the K-375 (see chapter 5.3.2 for details).

  • Page 141: Maintenance Work If Required

    7 Maintenance Maintenance work if required 7 7 1 Changing the buret tip The buret tip consists of the shaft with threaded clamping and slip-on tip . The buret tip is inserted into the receiver vessel using the distance holder Hose Threaded clamping Distance holder...

  • Page 142: Replacing The Buret

    7 Maintenance Inorganic substances Several minutes, e. g. with Improved cleaning action with HCl 0.1 mol/L or NaOH 0.1 warm solutions (40–50 °C) mol/L Organic substances Rinse off with a suitable organic For plastic shaft electrodes, (oil, grease, etc.) solvent (e.g. ethanol) or tenside take chemical resistance into solution account.

  • Page 143: Troubleshooting The Dosing Unit

    7 Maintenance 7 7 6 Troubleshooting the dosing unit If the dosing unit is blocked, this may be caused by the valve disc and the distributor disc adhering to one another. In this case cleaning of both discs may solve the problem. For the disassembly of the dosing unit refer to chapter “3.7 Disassembling the dosing unit”...

  • Page 144: Customer Service

    Addresses of official BUCHI customer service offices are given on the BUCHI website under: www.buchi.com. If malfunctions occur on your device or you have technical questions or application problems, contact one of these offices.

  • Page 145: Troubleshooting

    “Corrective measure”. The elimination of more complicated malfunctions or errors is usually performed by a BUCHI technical engineer who has access to the official service manuals. In this case, please refer to your local BUCHI customer service agent.
  • Page 146 8 Troubleshooting Boiling retardation/bumping/foaming ∙ Missing digestion rods or boiling stones are used ∙ Missing Antifoam tablet or other anti-foaming agent Typical mistakes distillation Samples do not get dark blue/brown after addition of NaOH ∙ Empty NaOH tank ∙ Air in NaOH hose ∙...
  • Page 147 8 Troubleshooting Problem Cause Corrective measure Nitrogen content too low ∙ Incomplete digestion ∙ Increase digestion time ∙ Insufficient H ∙ Increase volume ∙ Kjeldahl Tablets and H ∙ Correct ratio wrong ratio ∙ Nitrogen content per sample ∙ Not more than 200 mg tube is too high Nitrogen per sample tube ∙...
  • Page 148 Exchange boric acid with indicator by fresh solutions ∙ Incorrect ratio of indicator to ∙ Check and correct according boric acid, or incompatible to the BUCHI application indicator used notes ∙ Loose contact of the sensor ∙ Check cables and correct...

  • Page 149: Error Messages On The Display Of The

    The error messages consist of an error number and a short text explaining the problem. If the problem can’t be solved by the operator – please write down the error number and contact the BUCHI service for further assistance. Message...
  • Page 150 8 Troubleshooting 10’208 Sensor ‘steam pressure’ out of order Fault in steam pressure measurement, AD-converter or other hardware component. Call service. 10’217 Analog digital converter out of order Fault in AD-converter or other hardware component. Call service. 10’300 No cooling water flow detected. Check cooling water supply.
  • Page 151 8 Troubleshooting 14’001 Titrator not ready Check if all cables are plugged to the titrator, restart the system or call service. 14’002 Titrator information Call service 14‘003 Titrator not started Titrator error. Check function in System Prepa- ration/Buret function. Call service. 14‘004 Titrator not started, pH value too low pH value is below the set endpoint.
  • Page 152 8 Troubleshooting 14’602 Titrator stopped, maximal volume Make sure the electrode is in good working reached conditions, the correct titration solution is used and that no air bubbles are in titrator hoses. 14’603 Titrator stopped, stop endpoint Check the titrator and if enough titration solu- reached tion is available 14’604...

  • Page 153: Eliminating Errors Of The Kjelsampler

    If an error on the K-376 / K-377 cannot be eliminated, the KjelMaster K-375 can also be operated without the sampler. In this case deactivate the KjelSampler in the Settings menu.

  • Page 154: Eliminating Errors Of The Titrator

    In case the sampler arm of the K-376 or K-377 can not be moved by reason of an electronic failure, it can be lifted manually using a hand crank. The hand crank can be obtained from any authorized BUCHI representative. In case you observe any leakage between a sample tube and the sampler arm with the sealing cap, you may check the sample tube with the provided gauge.

  • Page 155: Taking Out Of Operation

    9 Shutdown, storage, transport and disposal Taking out of operation This chapter instructs how to shut down the instrument, how to pack it for storage or transport, and specifies the storage and shipping conditions. Before the device is shipped, ∙ the mains cable, ∙...

  • Page 156: Emptying The Buret Of The Titrator

    9 Shutdown, storage, transport and disposal Emptying the buret of the titrator Empty the buret of the titrator before shipping the instrument. Storage/shipping CAUTION Biohazard. ∙ Remove all dangerous substances from the device and clean it thoroughly. Store and transport the device in its original packaging. NOTE Move the K-376 sampler arm to the washing position for transport.

  • Page 157: Spare Parts

    Spare parts This chapter lists spare parts, accessories, and options including their ordering information. Order the spare parts from BUCHI. Always state the product designation and the part number when ordering spare parts. Use only genuine BUCHI consumables and genuine spare parts for maintenance and repair to assure good system performance and reliability.

  • Page 158: Spare Parts

    10 Spare parts Product Order number Picture Set condenser sealing 11058428 pH electrode (without cable) 11056842 Electrode cable 11057399 Stirrer rotor blade 043466 Stirrer rotor blade, colorimetric titration 11068266 Stirrer, complete 11056590 Dosing unit (20 mL) 11056836 Driving motor for dosing unit 11056835 Colorimetric sensor with cable 11066601...
  • Page 159 9 Shutdown, storage, transport and disposal K-375 / K-376 / K-377 Operation Manual, Version E...

  • Page 160: Hosing Connection Scheme Kjeldahl Sampler System

    10 Spare parts 10.2 Spare parts K-376 / K-377 Product Order number Picture Transfer unit, complete for K-376 11059035 for K-377 11059036 Dip tube 11056031 Dip tube with cross-slot 00047845 Drip tray K-376 / K-377 00043827 Sealing cap 11057284 10.3 Hosing connection scheme Kjeldahl Sampler System K-375 / K-376 ...

  • Page 161: Declarations And Requirements

    11 Declarations and requirements Declarations and requirements 11.1 FCC requirements (for USA and Canada) English: This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to both Part 15 of the FCC Rules and the radio interference regulations of the Canadian Department of Communications.
  • Page 162 F +66 2 862 08 54 F +971 4 313 2861 F +55 19 3849 2907 bacc@buchi.com middleeast@buchi.com latinoamerica@buchi.com www.buchi.com/th-th www.buchi.com www.buchi.com/es-es We are represented by more than 100 distribution partners worldwide Find your local representative at: www buchi com...

This manual is also suitable for:

Kjelsampler k-376Kjelsampler k-377

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