Calibrated dipsticks

Volume measurement is likely to be less accurate at plant scale, either because of the use of simple devices such as calibrated dipsticks, or because more sophisticated instruments such as scales or ultrasound-based devices cannot be used reliably. 

Measuring systems should be verified as accurate. Where dipsticks are used they should be used only with the particular vessel for which they have been calibrated. They should be made of suitable non-reactive, non-absorptive material. 

Overall, the advantages of the Dipstick and walking profiles are that they are lower-cost devices, easy to operate and accurate (Class 1 resolution ASTM E 950), and can be used to calibrate other profile devices. However, they are not ideal for measuring long lengths. 

The simplest instrument for the measurement of the volume of a liquid in a vessel is the dipstick or gauge stick. The dipstick is a straight rod, calibrated along its length, which is immersed vertically in the liquid so that its lower end touches the lowest point in the vessel On raising the dipstick the volume of liquid in the vessel may be read from the mark coinciding with the liquid level. A dipstick can only be used in the vessel for which it has been calibrated. 

What is meant by calibration Describe how you would calibrate a gauge (or sight) glass or a dipstick for a particular vessel. 

Manual gauging. Tank gauging started with manual gauging (Fig. T-7), using a graduated diptape or dipstick. This technique is still used worldwide, and is today still the verification for gauge performance calibration and verification. 

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