SM21-AL4電極
PH電極傳感器系列：SM21、SM21D、SR20、SR20D、SR20C、SC21、SM29、SC29、SM60
普通型：SM21-AG2、SM21-AG4、SM21-AG6、SM21-AL2、SM21-AL4、SM21-AL6
高溫型、耐化學腐蝕：SM21D-AG2、SM21D-AG4、SM21D-AG6、SM21D-AL2、SM21D-AL4、SM21D-AL6
SM21 Single Glass Electrodes
The glass membrane is the most important part of the complete pH measuring loop. pH sensitive glass has the particular property that alkali metal ions present in the texture of the glass are exchanged with H+ ions of the liquid. The selection of the correct type of glass electrode depends on both the type of glass membrane thickness of the glass membrane.
Two types of glass are available as described here:
”G” glass
This is used for the membranes of electrodes in processes where the nominal pH value varies between pH0 and pH10. Since this type of glass has a wide application range it is also termed “general purpose” glass.
“L” glass
The application of “L” glass is for measurements in alkaline media with high process temperatures.
Features
• low resistance glass for fast response and sensitivity
• High resistance glass for chemical resistance
• L-glass sensors for high temperature chemically harsh applications
• G-glass sensors for all general applications
• ”All glass” construction.
• Dimensions and design meet the requirements of DIN 19263.
• Isothermal point of intersection: pH 7 （nominal value at 0 mV）.
• Maximum pressure: 1000 kPa （10 bar）.
• Metal foil screening.
• Bulb membrane for general purpose.
• Dome shaped membrane for “Heavy Duty” applications.
Thickness of the glass membrane
Shockproof
A bulb shaped glass membrane suitable for general purpose
Heavy duty
This dome shaped glass membrane is suitable for harsh and abbresive applications.
Selection guide separate electrodes : Glass sensors
modelcode | Bulb type | Glass resistance （Mohm） | T range （°C） | Pressure （bar） | Applications | remark |
SM21（D）-AG2 | Universal | 25-50 | 0-80 | 10 | light laboratory | fast response high sensitivity |
SM21（D）-AG4 | shockproof | 50-100 | 0-100 | 10 | general | Universal |
SM21（D）-AG6 | heavy duty | 120-200 | 0-100 | 10 | Harsh | mechanically strong |
SM21（D）-AL4 | shockproof | 300-450 | 15-130 | 10 | High Temperature | T cont. ≥ 70°C high chem. Resistance |
SM21（D）-AL6 | heavy duty | 600-900 | 25-130 | 10 | High T + abbresive | T cont. ≥ 70°C high chem. Resistance |
* all pH glass sensors have a sodium error of 0.17 pH above pH=13 this because the glass then will see the Na+ ion as H+ ion. The pH reading is lower than it is in reality.
