Level sensors for water
Throughout the treatment of water and wastewater, level sensors for water have become the most important type of sensors to efficiently operate the process. In the past, the most common level “sensors” have been mechanical floats within a tube that would rise and fall as the depth changed. Yet, these units were failure-prone and unreliable, and did not provide sufficient information to cope with the rising degree of process automation.
Electronic level sensors for water therefore increased in demand as the need to control processes and the need to automate level monitoring systems increased. The need for higher automation and remote measurement solutions emerged due to the cost of sending a person to look at the level and due to the low reliability of mechanical floats. Thus, new electrical technologies have been developed as level sensors for water. In the more simple solutions, magnets are put in floats and reed contacts placed in the tube guide to give switch outputs, or an electrical current is passed down a conductive level probe to close circuits when water is present.
Continuous level monitoring with level sensors for water
Yet, these technologies only provide simple switch outputs, while in most stages of water treatment a continuous level monitoring is required. Therefore hydrostatic level transmitters were developed, especially optimised as level sensors for water, by using the special submersible pressure transmitter design. This technology has proved to be the instrument of choice by control and instrumentation engineers in water and wastewater management as it is a most flexible, simple to install and easy to calibrate level probe solution.
One of the major advantages is that these devices can be placed at the bottom of reservoirs, deep bore wells and tanks to provide continuous level monitoring. These level sensors for water can be submersed almost unlimitedly in depth, as they are submersed along a cable with freely variable length. Furthermore, as these units are immersed in the media, level probes are also unaffected by any surficial effects such as steam, foam, fat deposits, flotsam or spider webs.
To create really optimised level sensors for water, special methods to prevent water ingress into the electronics and to protect them from lightning and electrical surges have been integrated in these sensors and have therefore made submersible pressure transmitters become the de facto standard for level sensors for water when continuous measurement is required.
Although other measuring methods for continuous level control like ultrasonic or radar probes are now available in the market, submersible pressure transmitters remain the first choice for users seeking reliable level sensors for water.