Patent ID: 8888977
Filing Date: 2014-11-18
Classification: G01N

Abstract:
1. A combination electrode for ion concentration measurement, comprising a glass electrode and a reference electrode, wherein the glass electrode includes a glass support tube, and a sensitive glass membrane at a lower end of the glass support tube, the reference electrode includes a closed reference electrode chamber whose upper and lower surfaces are sealed, a reference electrode internal electrode made of silver-silver chloride, and a reference electrode internal solution, the reference electrode chamber being formed inside an outer tube having a liquid junction near a lower end thereof and around the support tube placed penetrating the outer tube along a substantially center axis thereof, the reference electrode internal electrode and the reference electrode internal solution being housed in the reference electrode chamber, a sealing means configured to seal the upper surface of the reference electrode chamber includes: an annular silver member which the glass support tube penetrates along a substantially center axis thereof; and annular sealing elastic members for liquid-tightly sealing a space between an inner periphery of the silver member and an outer periphery of the glass support tube, and a space between the silver member and the outer tube, respectively, wherein the annular sealing elastic members are each distorted and in direct contact with the annular silver member, such that the space between the inner periphery of the annular silver member and the outer periphery of the glass support tube and the space between the annular silver member and the outer tube are liquid-tightly sealed, and the reference electrode internal electrode is connected to a terminal for a reference electrode through the silver member.