Wire-guided float meter detector is a buoyancy type level measurement technique. For large level measurements (ie. 20m), wire-guided float detectors can be used. Basically, the function of bouncy type meters is that to use floats in the tank and record the float movement as the level in the tank raises.
Working:
The guide wires are connected to top and bottom anchors and assist in positioning the float as it moves with the fluid level. The tape is connected to the top of the float and runs directly up and over pulleys then down to the gauging head which is outside the tank at a suitable level for viewing.
The perforated tape is received in the gauge head by a sprocket counter drive. Any slackness in the tape is taken up by the tape storage reel which is tensioned. Tensioning of the tape storage reel is sufficient to ensure correct measurement, while not affecting the position of the float.
The shaft on the counter drive rotates as the float moves the perforated tape up and down. The rotary motion of the shaft is used to give a metric readout.
In atmospheric conditions, a seal is used to protect the sensing head from the process fluid. However, in pressurised applications, it is better to fill the head with the sensing fluid, particularly if the fluid is clean and lubricating.
Advantages:
- Large level measurement
- Intrinsically safe
Disadvantages:
- Large level measurement
- Intrinsically safe