manufacturer :       Metrohm

model :                   KF 756

annotation :           Dokumente engl .

The 756 KF Coulometer continues Metrohm’s established line of Karl Fischer instruments for the determination of low-level water contents. Despite its compact construction this instrument leaves no wishes unfulfilled. It comes equipped with a built-in printer and two RS 232C interfaces which allow communication with a balance, external printer and/or computer. This latest addition to the Karl Fischer range guarantees accurate and reproducible results even for water contents in the lower micro range. The dialogue languages English, French, German, Spanish, Portuguese, Swedish and Italian are standard, as is the backlit screen with its graphics capabilities. The screen not only provides a clear presentation of the parameters, but also shows graphically the course of the KF determination as µg water versus time. This facilitates the assessment of the determination and is a great help in method development and validation.

Depending on the amount of data that are to appear on the instrument display, large or small fonts can be selected.

A user list can be entered; the name selected from this list appears in the result report, which can be freely configured by simply selecting the lines containing the desired information.

Using the optional Remote Box you can connect a barcode scanner and a PC keyboard to the 756 KF Coulometer.

The KF reagent can be monitored with regard to the number of determinations carried out, its useful life span, drift value or capacity. Whenever the reagent has to be exchanged the corresponding request is issued automatically. To avoid mishaps of any kind there is the additional possibility of setting limits for the sample weight or volume and for the result. If one of these quantities lies outside the set limits, the corresponding warning message appears in the display and report and the “Remote” interface emits a signal.

One press of a button for renewing the KF solution

If a Dosino is connected to the 756 KF Coulometer the spent solution can be siphoned off by simply pressing a button. This starts a preprogrammed sequence which runs in the background and transfers the titration vessel contents via the Dosino into the waste bottle. Subsequently, fresh reagent is added to the KF cell. As the cell does not need to be opened during this operation, no humidity enters the cell, which therefore is ready for the next determination in a very short time.

Technical Specifications

Operating modes  

KFC                                        Coulometric KF titration

KFC-B                                    Coulometric KF titration with blank deduction

BLANK                                    Blank determination

GLP                                         Validation of the Coulometer

Endpoint indication

Voltametric , AC indication

I _pol        2, 5, 10, 20 or 30 µA (adjustable)

Iodine production  

Pulses of variable length and current intensity

Current at the generator electrode

100, 200, 400 mA

Titration rate  

Max. 2.24 mg H ₂ O/min

Determination range              

10 µg to 200 mg H ₂ O

Resolution

0.1 µg H ₂ O

Reproducibility  

Sample: water standard from a reagent manufacturer

10 µg < m( H ₂ O) < 1000 µg     ±3 pg

m (H ₂ O) > 1000 µg H ₂ O         ±0.3% or better

Drift compensation  

Automatic, manual or none

Materials

Housing                                   Powder-coated metal

Keypad cover                         Polycarbonate (PC)

Screen  

Graphical LCD, 192 x 64 dots, backlit

Field: 100 x 37 mm

Printer  

Built-in thermal printer

Paper width 57 mm

144 pixels or 24 characters per line

Memory  

Method storage for approx. 100 methods

Silo memory for sample data and results

Stirrer control
Switching on/off either manually or coordinated with the titration process

RS 232 interface

2 separate interfaces, each can be configured for printer, balance or computer connection: completely controllable from external control unit

Remote I/O lines

Connection for KF drying oven, 774 Oven Sample Processor, robot

With optional Remote Box: connection for barcode reader and PC keyboard

Dosino connection

For automatic reagent exchange

Ambient temperature

Nominal operation range         5 ... 40 OC

Storage                                    - 20 ... 60 OC

Transport                                 - 40 ... 60 OC

Safety specifications

Designed and tested in accordance with IEC publica-tion 1010, safety class I.

Power connection

Voltage                                     100 ... 240 V ± 10%

Frequency                               50 ... 60 Hz

Power consumption                max. 38 W

Fuse                                        2 x T1 H 250 V (only to be replaced by Metrohm Service using the same type)

Additional electronic overload protection

Dimensions

Width                                      145 mm

Height                                      194 mm

Depth                                      307 mm

Weight, including keypad       

Approx. 4.5 kg