با اجازه منا خانم
من هم یه اطلاعاتی از یک هند بوک دارم که کم کم براتون میذارم.مشکلش اینه که انگلیسی است.زحمت ترجمه اش پایه خودتون!
از اندازه گیر های لول(level) شروع می کنم.
اگر فکر می کنید به درد بخوره ادامه بدم و گرنه بیخیالش.
Float
Principle of Measurement
A float (see figure 5-4) consists of a hollow ball that rides freely on the surface of the liquid. Its position is a direct indication of level. The float is connected to an arm that operates a microswitch or a pointer and scale through a bearing. The spherical shape of the ball provides maximum volume—that is, maximum buoyancy—for its weight. For maximum sensitivity, the ball should be selected so it will sink to its largest (middle) section. This produces the largest force available to overcome friction and inertia of components.
Application Notes
Float devices are low in cost and simple in design. They are also accurate and reliable. However, for turbulent liquids they require the use of stilling wells, they are physically large, and they are generally used for clean services only. To maintain the float’s accuracy, liquids must have a fixed specific gravity. In addition, the float instrument is in contact with the process material, and buildup on the float will affect performance. Corrosion and chemical reactions are also a concern. The float’s effective travel is limited by its construction; typically, the angle of measurement is limited to ±30 degrees from the horizontal.
Generally, the float is not installed directly on top of pressurized vessels. If it is, the vessel may have to be taken out of service in order to do maintenance on the float. For this reason, external cage-type instruments are preferred. They are isolated from the process vessel by isolating
valves. The movement of the float, linkages, or levers must not be restrictedfile:///C:/DOCUME%7E1/hadi/LOCALS%7E1/Temp/moz-screenshot-1.png
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