Specific Gravity (SG) is the ratio of object’s density to that of water. Since water has a specific gravity of 1 at sea level, liquids and substances with a lower specific gravity will float. For example a float with a specific gravity of 0.6 will float with approximately 60% of its volume submersed in water.

Liquid Level Control of your fluid with a pump or valve can easily be achieved by combining your SMD Fluid Controls product with a relay or controller.

Choosing the correct switch materials can often mean the difference between years of dependable service and equipment failure. Materials that work well in oils or petroleum products may not be the best for common detergents or hot water.

• Stainless Steel – Ideal for high temperatures, high pressures and corrosive environments such as food equipment, industrial tanks or durable general use.

• Brass, Nylon or PBT stems with Buna-N Float – Good for petroleum products, oils and wastewaters. Buna-N floats have superior buoyancy and can be configured for oil-water interface detection.

• General Use Plastics – Polypropylene, PVC and Polycarbonate good to 105 degrees Good choice for general use, acids or food applications. Can be designed economically or custom molded with additional features for OEM applications.

A glass reed switch is hermetically sealed inside the stem from the liquid environment. “Normal” float position means the fitting and wires are on top and the float is resting at the bottom of its travel range (the liquid is too low to raise the level of the float).