WTW SenTix HW Precision PH Electrode with Ground-glass Diaphragm for Low-ion Media, S7 Connector, 170 mm, 103650

The WTW SenTix HW is designed for low-ion media such as fully demineralised water or condensate and features an adjustable orifice diaphragm: the user can control the amount of reference electrolyte that flows out via a thread on the shaft.

Ground joint with adjustable flow

To adjust it, hold the measuring chain with the glass membrane facing downwards and open the ground joint using the special key provided until electrolyte is visibly escaping and the ground joint is completely wetted. It is then closed again with gentle pressure until you feel resistance caused by the rough ground surfaces rubbing against each other. The ground joint can be opened further to achieve higher flow rates. For cleaning, the ground joint core can be unscrewed completely.

Glass shaft and measurement data

The glass shaft is 170 mm long and has a diameter of 12 mm. The pH measurement range is from 0 to 14, the permissible temperature range is from 0 to 60 °C, and the membrane resistance is less than 800 MΩ. A temperature sensor is not fitted. With an integrated NTC sensor and a range of -5 to 100 °C, this ground-joint design is available as the SenTix HWD with a fixed cable.

Refilling the electrolyte and connection

The reference system consists of 3 mol/l KCl, Ag⁺-free. As electrolyte flows through the diaphragm into the sample during operation, it is topped up via the refill port; the supplied dropper bottle is intended for this purpose. The port remains open during calibration and measurement. The SenTix HW is connected via the S7 connector head using an AS/DIN cable (order no. 108110 or 108112) or an AS/BNC cable (108114), neither of which is included in the Scope of delivery.

Alternatives and maintenance

The SenTix 60 is a glass electrode with a platinum wire diaphragm and a temperature range up to 100 °C. With the SenTix HW, the measuring chain is left overnight in the soaking cap filled with reference electrolyte; the refill opening is closed. Protein residues are removed using a pepsin cleaning solution; after each cleaning, the electrode must be conditioned for at least one hour and recalibrated.

Typical applications

• Boiler feedwater, condensate, distilled and fully demineralised water
• Low-ion media, rainwater and mineral water
• Cooling water, dye solutions, electroplating baths and salt solutions
• Emulsions, suspensions and sulphide-containing liquids
• Beer, lemonade, fruit juice, vegetable juice, wine, milk, yoghurt, quark, coffee extract, honey, jam and vinegar
• Hair dye, mouthwash, shampoo and household cleaners
• Enzyme solutions, gastric juice, infusion solutions, serum, Tris buffer solutions, urine and soil extract

Technical details

Scope of delivery

• 1 WTW SenTix HW pH measuring chain with rinsing cap
• 1 dropper bottle with reference electrolyte for refilling
• 1 special key for the ground joint
• Connection cable not included; available separately

Individual requirements and procurement service

Connection cables, KCl-250 reference electrolyte (order no. 109705), PEP/pH pepsin cleaning solution (109648) and buffer solutions are available on request from LT Laborhandel. Our procurement service can assist you in choosing between ground, ceramic and platinum-wire diaphragms.