横河SM21-AL2电极 PH计SM21-AL2横河
横河电机有限公司创建于1915年,总部设在日本东京。在世界29个地区拥有60多家子公司。经营领域涉及测量、控制、信息三大领域,在工业控制行业是zui为专业的跨国公司之一。1975年*研制出世界上*套具有划时代意义的集散型控制系统(DCS系统),对石油、化工等大型工厂的生产过程进行测量、运行监视和控制,为工业的发展和社会的进步做出了*贡献,到目前已相继推出了7代CENTUM DCS系列产品,流量表、变送器、分析仪等现场仪表也得到了用户的高度评价
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SM21
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.