Choosing a Sensor type

When you buy a HyDip device to send readings to your laptop you also need a sensor (or gauge) to take tank level measurements.

All gauges with a two-wire 24V, 4...20mA linear response will work with HyDip devices, but which is right for your tank?

Every tank level gauge functions by detecting some physical property of the product (height, weight/pressure, capacitance) which varies with the volume of the product, and convert it into an electronic signal. This signal can then be read by a HyDip device, either locally or using a laptop or smart phone via the internet.

Types of sensor

Gauges are either immersive or non-contact sensors.

Immersive sensors, often hydrostatic types, are designed to be placed in direct contact with the material being measured.

Non-contact sensors, as the name suggests, don't touch the inventory in the tank and instead are mounted above the material (commonly in the roof of the tank). Non-contact types include radar and ultrasonic sensors.

Hydrostatic immersive pressure sensor

These sensors lie at the bottom of the tank and detect the pressure applied by the liquid as the level rises and falls. A cable sends readings to a unit mounted above the tank.

Read more about hydrostatic pressure sensors here.

Vega immersive hydrostatic gaugeVega immersive hydrostatic gauge

Vega immersive hydrostatic gauge

Magnetostrictive immersive sensor

This is a tried and trusted approach using a float guided by a rod that extends from the top of the tank to the bottom.

Read more about magnetostrictive sensors here.

Magnetostrictive gaugeMagnetostrictive gauge

Magnetostrictive gauge

Guided wave radar immersive sensor

These gauges use a microwave pulse like a regular radar sensor, but guide them along a rod to focus the pulse with several advantages.

Read more about guided wave radar sensors here.

Vegaflex81 Guided wave radar gaugeVegaflex81 Guided wave radar gauge

Vegaflex81 Guided wave radar gauge

Capacitive immersive sensor

Commonly used with highly corrosive products, high temperatures and/or pressure, these gauges measure fluctuations in capacitance between a steel rod and the tank wall.

Read more about Sensors: capacitive (RF).

Vegacal 65 Capacitive gaugeVegacal 65 Capacitive gauge

Vegacal 65 Capacitive gauge

Other considerations

Level detection vs continuous level measurement

Where you are seeking to monitor change in a tank with 'continuous level measurement' that some types of device only offer 'level detection', telling you when a liquid has reached one particular level. These point-level sensors, which include vibration sensors and capacitive electrodes, are simple yes/no overflow or low level sensors.

Explosion ratings

If a sensor is required inside a hazardous zone, e.g. one where explosive gases or vapours are present, only use sensors rated for use in hazardous environments. If you're unsure ask an expert for guidance.

The HyDip device is NOT certified for use in a hazardous zone, although it may be connected to a sensor that is, and be sited elsewhere.

Which gauge is for you?

Selecting the right gauge for your situation can require discussion and thought. Cost, suitability, ease of installation and accuracy are just some of the factors that figure in a decision.

If you would like help choosing a sensor for your application, call us and we'll be happy to assist.