LevelSite is a magnetic rotary indicator. It is a reliable level measurement system for applications with operating pressures up to 4500 psig (310 bar), operating temperatures up to 600°F (316°C), and with liquid to a minimum specific gravity of 0.5049. LevelSite’s visual indicators and electrical switches are isolated from the liquid; the tank remains sealed from the surrounding environment (See Figure 2). Accidental spills from sight-glass breakage are eliminated. LevelSite consists of 3 major components: the float housing, a magnetic float, and the rotating flag assembly. The float housing is an engineered pressure vessel which is externally mounted to the tank. The float housing is designed to handle the same temperatures and pressures found in the tank. It is fabricated from a variety of materials, depending on the application. The alloy models are usually stainless steel. Engineered plastic models use polyvinylchloride (PVC), polypropylene (PP) or polyvinyliden fluoride (PVDF). Other materials are available on request. The float (See Figure 3), is equipped with a permanent ring magnet assembly. This assembly rides at the surface of the liquid contained within the float housing, rising and falling as the liquid in the tank rises and falls. As the float moves up and down, a magnetic flux field maintains continuous contact between the magnetic float and the rotating flag assembly. The rotating flag assembly is connected to a switch on the float housing. When the float rises and falls, the magnetic flux is cut off and reconnected, causing the switch to open and close. The switch controls a relay connected to the control system. If the switch is closed, the relay opens and sends a signal to the control system indicating that the liquid level in the tank is high. If the switch is open, the relay closes and sends a signal to the control system indicating that the liquid level in the tank is low.
This supplemental guide from Barksdale describes the LevelSite magnetic rotary indicator, a level measurement system for tanks that uses a magnetic float inside an externally mounted float housing and rotating flags mounted outside the housing. It explains the operating principle, the main components (float housing, magnetic float and rotating flag assembly), and the materials and finishes available for alloy and engineered plastic versions.
The guide also lists operating principle details and general specifications such as pressure, temperature and minimum specific gravity limits, then gives operating instructions covering general installation, mechanical installation, electrical installation, commissioning and installation of a tank level indicator (TLI) transmitter. Bulletin #L0018-D, dated 02/08.
| Maximum operating pressure | 4500 psig (310 bar) |
|---|---|
| Maximum operating temperature | 600°F (316°C) |
| Minimum liquid specific gravity | 0.5049 |
| Indication resolution | 1/2" (12.7 mm) |
| Rotating flag assembly width | 1.18" (30 mm) aluminum; 1.02" (26 mm) polycarbonate |
| Float housing materials | Stainless steel alloy; PVC, PP or PVDF engineered plastic |
| Anodized aluminum flag service temperature | Up to 400°F (200°C) |
| Painted flag service temperature | Up to 600°F (316°C) |
| Polycarbonate flag housing temperature | To 250°F (121°C) |
| Polycarbonate flag housing visibility | 180° (front and sides) |
| Standard process connection patterns | Top/bottom, top/side, side/side, side/bottom |
| Transmitter cable length | Up to 3 miles |
It is used for applications with operating pressures to 4500 psig (310 bar) and operating temperatures to 600°F (316°C).
It must always be mounted vertically, with the tank flanges accurately aligned with the flanges on the LevelSite.
Because the operation of the LevelSite is based on the magnetic field principle.
The cable length may be up to 3 miles, and the transmitter housing should be grounded if necessary.