The surface height of the contents of a tank, reactor, or other container can be determined using a method called level measuring. The plant must have an accurate and trustworthy level measurement system to ensure the security and profitability of all manufacturing activities.

When measured incorrectly or inappropriately, they can lead to abnormally high or low vessel levels. Damage to equipment can occur at low levels, and overflow at large levels can threaten public health and safety.

A level is the vertical distance between a fixed point on the base of the container and the top of the contents within the container.

Measurement Fundamentals for Levels

Level Measurement

Direct technique and inferred method liquid level measurement devices are the two main categories. Your car’s dipstick, which gauges oil level in the oil pan, is an example of a direct method.

The inferred technique is illustrated with a pressure gauge installed at the base of a tank to monitor hydrostatic head pressure in relation to liquid height.

Transparent Level Gauge

For temperatures and pressures up to 450 psig and 400°F, gauge glasses composed of tubular glass or plastic are utilized in service. A special gauge glass is employed if the internal pressure or temperature of a vessel needs to be determined.

The gauge glass used here features a metal housing and a glass or quartz window through which the liquid level can be observed. For reasons of both stability and security, the glass part is typically flat.

Pressure Gauge with Reflex Readings

The reflex gauge glass is a subset of the gauge glass family. The glass part of this type has a prism form on one side. One side of the glass is shaped with parallel 90-degree angles. The outer surface of the glass is hit by light rays at a right angle.

The light rays enter the glass at an angle of 45 degrees and strike the inside surface. Depending on whether or not there is liquid inside the chamber, light rays will either be refracted inside the chamber or reflected back to the exterior of the glass.

Radiation Level Gauge

The refraction type is the third and final category of gauge glass. In low-light conditions, this type’s lights, which are often affixed to the gauge glass, come in handy. The concept relies on the fact that the refraction of light changes when it passes through different materials.

When passing through water, rather than steam, the path of the light is curved more sharply. The red lens is activated when light travels along relatively straight paths through the steam-filled section of the chamber.

Light rays enter the chamber and are deflected by the water, shining through the green lens. The green section of the gauge represents water, while the red section represents the area above that level.

Why Is Level Measurement Crucial?

For many industrial applications in the bulk material handling industry, measuring the exact level of the material in a tank or vessel is essential.

Inventory: In order to keep tabs on materials in terms of volume or weight, it is essential to measure the level of the inventory.

Productivity Maximization: Taking precise readings of levels is useful for improving productivity.

Safety: Low levels can harm equipment, and excessive levels might overflow and potentially create safety issues, therefore it’s important to have correct readings.

Technologies for Measuring Levels

There are primarily two ways to categorize Level measurements, depending on the methods used to take the reading:

Concentric Metrics

Point level sensors are used to monitor a specific level of a fluid, slurry, or solid medium. An output or indicator will be generated once the material hits a predetermined threshold.

Point level measurement sensors include things like capacitance probe switches, mechanical floats, rotating paddle switches, vibrating tuning fork switches, and single and multi-point level switches. These are the various instruments used to gauge depth.

Continuous Level Measurement

Tanks, vessels, and other types of open and closed storage systems can have their contents constantly monitored by means of level measurement sensors. Sensors such as Continuous Level Radar Sensors, Hydrostatic Transmitters, Guided Wave Radar Level Sensors, Magnetic, Ultrasonic Level Sensors, Pneumatic Visual Level Indicators, etc. are used to take continuous readings of a liquid’s level.

Summary

We have seen some simple level sensors and learned about the basics of level measuring in this article. Point measurements are taken using sensors like capacitance, resistance, tuning forks, etc.

Continuous level measurements are often taken with ultrasonic or optical level sensors. Those are the several tools for measuring height.