Level gauges take level readings using several different techniques. The measurement technology should be chosen based on the user’s application. These level sensors also have different display options based on user preference.
Magnetic level gauges – A magnetic level gauge is used to control the level of fluids. The gauges operate under Archimedes Principle, which states that any object submerged in a fluid experiences the same buoyant force as the weight of the liquid displaced. Magnetic level gauges are extremely durable and can be used in applications that would break or destroy glass gauges. They can be used underground with a maximum working temperature and pressure range of 4000C and 220 bar. These gauges are capable of inter-phase level detection, even in highly toxic or corrosive mediums.
Reflex level gauges – A reflex level gauge is used to detect level in a vessel or container. It operates by using the dissimilarity in the index of refraction between fluids and vapors. They are usually made of carbon or stainless steel, which provides the durability needed to work in a temperature and pressure range up to 400°C and 400 bar respectively. If the vessel is filled with vapor, the observer will see a silvery white color because the light radiations running into the grooved surface of the sight glass will be completely reflected. If the vessel is filled with liquid, the observer will see black because the light radiations coming across the liquid region will be completely absorbed. The sight glass is a transparent tube which is clamped to the gauge body.
Transparent level gauge – Transparent level gauges are very similar to reflex level gauges. They consist of two transparent glasses which are integrated with the liquid cavities on both sides. Transparent level gauges work by detecting the dissimilarity in the transparent characteristics of two glasses which are integrated with the liquid cavities on both sides. In an application which uses water and steam, an illuminator is employed to make the liquid level easier to see. The light rays emitted by the illuminator are directed in an upward direction towards the water column causing the surface of the liquid to become illuminated. The light radiations generally fall upon the divided surface between water and steam and then reflect back to the eye of the user.
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