LEVEL SENSORS, CONTROLLERS, & INDICATORS:

Level Indicators & Transmitters -- Sound, Affordable, Delivered Fast

C.R.T. offers a number of different options when it comes to controlling and inventorying the amount of liquid in your tank. Prices can range from $100 per tank to well over $5000 per tank, depending on the style, wetted surface, tank size and display that you require.

1. Magnetic Float Switch. This type of unit is often used in O.E.M. applications where an inexpensive level indicator is needed to control a pump, an alarm, a valve, a mixer or some type of single control. Each unit can easily be mounted at the desired depth in a tank through a tank inlet and wired to a control panel. Prices will greatly vary on material of construction. Advantage: Price. Disadvantage: only one signal per unit, mechanical movement of float can be faulted by flow, viscosity, stickiness, or temperature.
2. Multiple Magnetic Float Switch. This unit extends down in to the depths of the tank and uses multiple magnetic switches inside the length of the float stem. It can indicate numerous levels at which pumps, valves, alarms, etc., can all be turned off and on to control the inventory inside of that tank. Advantage: Multiple level switches within one unit, price. Disadvantages: float is a mobile wetted part and can be interrupted by flow, suspended solids, stickiness, etc.
3. Board Level Gage. This type of unit incorporates an oversized float inside of the tank connected to a cable. The cable exits the tank via a pulley system, and is connected to a pointer which indicates the level of the liquid on a calibrated board mounted along the sidewall of the tank. Advantage: Price is right, especially for very large tanks, at about $1200 ea. Float-counter weight system is relatively foolproof. Relays can be added for about $600 per pair. Disadvantage: Primitive, and a close, visual accessibility of the tank is usually required.
4. Ultrasonic Level Switch. This type of unit can indicate continuous levels throughout the tank and can control instrumentation at any level as many times as is required - depending on the amount of relays placed inside the digital display. This unit observes the level by bouncing a radar signal off of the surface and measuring that distance to and from that surface. Advantage: No wetted parts-- so failure of system is avoided regardless of liquid characteristics. Disadvantage: More expensive (from $1400 and up with 4 relay digital display box included); thick heavy fume clouds can trigger faulty signal.
5. Load Cells. These units actually weigh the entire vessel and its contents and continuously indicate weight via a display while the tank is being filled, etc. The display box can include relays wired to control valves, pumps, alarms, mixers, etc. which, in turn, can regulate the contents of the tank. Advantage: No wetted surfaces; in fact, the indicator does not even need inside access to the tank. Disadvantage: Expensive; units start at about $2000 per tank (with a digital display) depending on the total "full capacity weight" of the tank.