US 11,940,409 B2
Digital pH sensor and measuring method of a digital pH sensor
Thomas Wilhelm, Chemnitz (DE); and Michael Hanko, Dresden (DE)
Assigned to Endress+Hauser Conducta GmbH+Co. KG, Gerlingen (DE)
Filed by Endress+Hauser Conducta GmbH+Co. KG, Gerlingen (DE)
Filed on Oct. 21, 2020, as Appl. No. 17/076,157.
Claims priority of application No. 10 2019 128 621.2 (DE), filed on Oct. 23, 2019.
Prior Publication US 2021/0123885 A1, Apr. 29, 2021
Int. Cl. G01N 27/416 (2006.01); G01K 13/00 (2021.01)
CPC G01N 27/4167 (2013.01) [G01K 13/00 (2013.01); G01N 27/4161 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A digital pH sensor for measuring a pH in a measurement medium, comprising:
an electronics unit; and
a sensor housing having a first half-cell and a second half-cell,
wherein the first half-cell is a reference half-cell having: an electrolytic junction; a first electrolyte; and a first electrode in contact with the first electrolyte and electrically connected to the electronics unit,
wherein the second half-cell is a measuring half-cell having: a second electrolyte; and a second electrode in contact with the second electrolyte and electrically connected to the electronics unit,
wherein the first half-cell and the second half-cell are adapted to form a potential difference between the first electrode and the second electrode if the digital pH sensor is in contact with the measurement medium,
wherein the electronics unit is programmed with a correction function for converting the potential difference into a digital measured value, wherein the digital measured value is either a voltage value or a pH value,
wherein the first electrolyte and/or a material of the first electrode and/or the second electrolyte and/or a material of the second electrode are selected such that the potential difference between the first electrode and the second electrode, at a pH value of the measurement medium of 7 and a temperature of the measurement medium of 25° C., includes a preset potential difference that is greater than 30 mV or less than −30 mV, and
wherein the electronics unit programmed with the correction function is configured to convert the potential difference into the digital measured value and apply the correction function for correcting out the preset potential difference such that, at a pH value of the measurement medium of 7 and at a temperature of the measurement medium of 25° C. and the potential difference of greater than 30 mV or less than −30 mV, the digital measured value is 0 mV if the digital measured value is output as a voltage value or 7 if the digital measured value is output as a pH value.