Foam Detect and Level Monitor, otherwise known as Charis, have been designed and distributed across Australia by Semrad Pty Ltd since 1994.
Foam Detect and Level Monitor created by Semrad Pty Ltd are designed uniquely for foam (Please note that some other manufactures simply modify liquid sensors. These sensors will not be as effective)
One of the main problems that can occur with Foam Detect and Level Monitors is that they foul due to a buildup of sticky covering on the sensor. Semrad Pty Ltd have overcome this problem in their design by installing an individual IMA Sensing® technology which prevents the sensors from fouling even when there is a buildup of foam and product.
Foam Detect and Level Monitor can be used with biotech, food, sugar, brewing, wastewater, effluent treatment and chemicals. They have a high accuracy rate and a high pressure and temperature range.
Foam
F0am is made up of trapped bubbles in a liquid or solid, separated from one another by films of liquid. Although foam is fragile, the liquid films are resilient and have a plastic quality. The bubbles are spherical when the liquid films are quite thick, approximately 0.01mm.
Manufactured foams have special properties, such as low density, lightness and compressibility, that make them suitable as thermal insulators, flotation devices, and packing material. Liquid foams are often used to extinguish fires and are called fire retardant foams. However many foams are simply a by-product formed in chemical processes through agitation or aeration of liquids. So foam controllers are used to remove the foam.
Foam Controllers
Foam can cause many problems in process equipment by fouling level sensors leading to overflows, as well as reducing the speed of machinery. Foam can reduce pump efficiency, reduce the capacity of the tank, allow bacteria to grow, formation of dirt deposits, reduced effectiveness of the liquid solution, drainage problems for sieves and filters, and additional costs of cleaning, downtime and imperfect products. Factors that may produce foam include leaky seals on pumps, high pressure pumps, or poor system design for the inlet and outlet of a tank.
To sense foam in a tank or in the process equipment a specialised foam sensor and controller should be used. Specialised foam sensors will ensure that they are not fouled up and still work reliably even when covered in foam. A defoamer is also used to reduce and prevent the generation of foam through adding chemicals to the process liquid. Defoamers can address both surface foam and entrained air. A defoamer is insoluble, has low viscosity and an ability to spread rapidly on foamy surfaces. It causes the rupture of air bubbles to break down foam. However in food and pharmaceutical processes chemical defoamers cannot be used because of risk of contamination, so mechanical methods are used.