Abstract: An apparatus is disclosed for electronically and non-invasively sensing liquid level in a boiler or other liquid-containing vessel. The apparatus, comprising a sensor and sensor integrated circuit can be uniquely designed for external attachment to any commercially available gauge glass used for visually determining liquid level in a boiler and other liquid-containing vessels. The apparatus, which employs proximity level-sensing technology, is suitable for determining liquid level provided the liquid-containing boiler or vessel is metallic and the liquid is electrically conductive, for example water and other aqueous solutions. The apparatus can additionally comprise at least one, preferably two externally located electrical pushbutton switches, for example “water feed” and “test”, for manually adding water to the boiler and for testing the apparatus' proper working condition with a simulated low water condition, respectively.

Abstract: An apparatus is disclosed for electronically and non-invasively sensing liquid level in a boiler or other liquid-containing vessel. The apparatus, comprising a sensor and sensor integrated circuit can be uniquely designed for external attachment to any commercially available gauge glass used for visually determining liquid level in a boiler and other liquid-containing vessels. The apparatus, which employs proximity level-sensing technology, is suitable for determining liquid level provided the liquid-containing boiler or vessel is metallic and the liquid is electrically conductive, for example water and other aqueous solutions. The apparatus can additionally comprise at least one, preferably two externally located electrical pushbutton switches, for example “water feed” and “test”, for manually adding water to the boiler and for testing the apparatus' proper working condition with a simulated low water condition, respectively.

Abstract: A liquid flow metering system is disclosed which includes a pump disposed between a liquid supply and a reservoir. The reservoir includes an inlet connected to the pump, an air/liquid outlet and a liquid outlet. The air/liquid outlet is connected to an air separation chamber. The liquid outlet is connected to a flow meter and a liquid outlet valve. The air separation chamber is connected to an air outlet. The air outlet is connected to an air release valve. The air separation chamber accommodates an optical sensor for sensing the presence of air in front thereof and within the air separation chamber. The optical sensor, air release valve and liquid outlet valve are all linked to a controller. When the optical sensor senses air in front of the optical sensor, the sensor sends a signal to the controller to open the air release valve and close the liquid outlet valve.