Which level control solution is best when considering a pump system design? With a wide variety of different options including float switches, ultrasonics, conductivity probes and vibrating forks, the answer will depend on factors including the medium or liquid type, required accuracy and budget. Let’s take a look at the best level control solutions for different applications and budgets.
Liquid or Medium
The first thing to consider when selecting a level control solution is the medium it will be installed in or used to measure.
For water applications, consider if this is Potable (drinking water) or waste/grey water.
Float switches are ideal for both clean water and wastewater applications. They are one of the most popular solutions, offering a relatively inexpensive solution and many different variants to suit a wide range of requirements.
Conductivity level control solutions such as probes also lend themselves to largely clean or grey water applications, where the risk of solids adhering to the conductive rods is minimal.
Corrosive Liquids and Viscous Mediums
‘Non-contact’ level control solutions such as ultrasonic are especially suited to corrosive liquids such as those used in process control. This involves an echo being bounced from a datum surface and timed until the signal is received back in order to determine the level.
They are also suited to very dense viscous mediums where contact with any measurement and control items would prove problematic.
Varying other forms of non-contact level control, such as radar, can be the perfect option in cases where there is constant surface movement that would make control via an ultrasonic echo difficult - for example, tidal applications in heavy seas.
Working with powders presents other issues, for which tuning forks provide the ideal level control solution. The level switch incorporates a piezoelectric crystal that vibrates the fork at its natural frequency. When the fork comes in contact with a material, the vibration is dampened and the switch changes state.
How critical is the level reading required? It is important to weigh up the cost of the solution versus the features that are needed for the application.
If it is a case of a simple on/off action like turning on a pump, or energising a solenoid valve, then cost-effective floats or conductivity probes provide the ideal solution.
Should extremely accurate level readings be required, or volume calculation of tank contents per say are needed, then Ultrasonic level control is the most obvious choice, with factors such as temperature compensation, and intelligence built into the units, to cover a wide range of applications and scenarios.
However, all this technology comes at a price, which leads us very nicely onto the next point, which is economics of purchase.
Both float switch and conductivity probes are relatively inexpensive in terms of costs to implement, with floats being the most cost effective as a rule. The use of conductivity probes will also require a control relay which could be costly to incorporate if the control system is existing.
If the budget allows, then Ultrasonic ‘non-contact’ level control, or tuning fork type level control, is the budget busting but highly effective, all-round choice balancing both accuracy, life expectancy, and flexibility of the equipment.
Explore our range of level control solutions here.
For expert advice on selecting the best solution for your application, chat to our friendly team on +44 (0)1630 647200.