What Is Density Meter? and Types

What Is Density Meter?

Density meters are instruments that measure the density of a sample liquid or gas. The density meter is also known as an online liquid density transmitter. It can also be called a densitometer, density sensor, density analyzer, or inline hydrometer.

The industrial density meter is used to monitor and control the concentration and density of liquids or gases in production. This instrument is reliable and easy to use. It generates a 4-20mA or RS485 signal. The signal can be calibrated and monitored remotely.

What Is Density Meter

Types of Density Meters

How to classify and select industrial density meters?

There are five different kinds of densitometers: tuning fork, Coriolis, differential pressure, radioisotopic, and ultrasonic. Here’s a brief introduction.

1. Tuning fork density meter

The sensor is designed according to the principle of vibration. This vibrating element resembles a two-toothed tuning fork. The fork is vibrated by a piezoelectric crystal located at the root of the tooth. The frequency of the vibration is detected by another piezoelectric crystal. Through phase shifting and amplification circuits. The fork is stabilized at the natural resonant frequency. The liquid flowing through the fork causes the vibration to change. This change in vibration alters the resonant frequency. The electronic processing unit calculates the accurate density value.


Simple installation, plug and play, maintenance-free. The density of mixed media containing solids or air bubbles can be measured.


The density meter is not ideal for measuring crystallization and fouling media.

Typical application:

Petrochemical industry, food and wine industry, pharmaceutical industry, organic and inorganic chemical industry and mineral processing (such as clay, carbonate, silicate, etc.).

This is mainly used to detect interfaces in pipelines and control concentrations in various industries. This tool is used in brewing to measure wort concentration and in controlling acid-base concentrations. It is also used to refine sugar and detect the density of stirred mixtures. Reactor end point detection, separator interface detection, etc.

2. Coriolis online density meter

Working principle:

The measuring tube vibrates continuously at a certain resonant frequency. The vibration frequency changes with the density of the fluid. Therefore, the resonant frequency is a function of the fluid density. The density of the fluid can be accurately obtained by measuring the resonant frequency. The density measurement can also directly measure the fluid’s mass flow rate in the closed pipeline. This is done using the principle of Coriolis force.


The mass flowmeter can measure mass flow, density and temperature at the same time. Moreover, the measurement accuracy is high and the operation is stable. Therefore, it is widely used in the flow and density detection and control of the production process in the petrochemical field.


The price is relatively high, and it is easy to wear and block when used to measure granular media.

Typical application:

This device has many uses. In the petrochemical industry, it can detect oil levels and interfaces. In the food industry, it can be used for processing grape juice, tomato juice, and more. It also has applications in the dairy and paper industries. Additionally, it can test various chemical substances. It can also be used in mining brine, potash, natural gas, lubricating oil, biopharmaceutical and other industries.

3. Differential pressure density meter

Measuring principle:

The differential pressure density meter is the gravity difference △P=ρgh generated by the liquid column. When h remains constant, the differential pressure value measured by the transmitter is divided by gravity and length to find the density.


The differential pressure density meter is a simple, practical and cost-effective product.


This product has some drawbacks. It needs to be installed vertically, has a large margin of error, and the measurements it provides can be unstable.

Typical application:

The sugar industry and the winemaking industry both produce different types of liquids. These liquids include fruit juice, syrup, and grape juice. They also produce alcohol with different strengths, such as ethane and ethanol.

Dairy industry: condensed milk, lactose, cheese, dry cheese, lactic acid, etc.;

Mining: coal, potash, brine, phosphate, the compound, limestone, copper, etc.;

Oil refining: lubricating oil, fragrance, fuel oil, vegetable oil, etc.;

Food processing: tomato juice, fruit juice, vegetable oil, starch milk, jam, etc.;

Pulp and paper industry: black pulp, green pulp, pulp cleaning, evaporator, white pulp, caustic alkali, etc.;

Chemical industry: acid, caustic soda, carbamide, detergent, polymer density, ethylene glycol, sodium chloride, sodium hydroxide, etc.;

Petrochemical: natural gas, oil and gas washing, kerosene, lubricating oil, oil/water interface.

4. Radioactive isotope density meter

Working principle:

The instrument of the radioisotope density meter is equipped with a radioisotope radiation source. The radiation detector detects the radioactive radiation, like gamma rays. It receives the radiation after passing through the measured medium. When the thickness of the medium is constant, the attenuation of rays is only a function of the material density of the medium. The density value can be obtained through the calculation inside the meter.


The radioactive densitometer can measure the material’s density and other parameters inside the container. It doesn’t need to touch the object being detected. This is especially useful in harsh conditions like high temperature, high pressure, corrosion, and toxicity.


The pipeline’s inner wall gets worn and scaled, leading to measurement errors, difficult approvals, and strict management.

Typical application:

This device is commonly used in various industries like petrochemical, steel, and mining. It measures the density of liquids, solids, and substances like coal powder and cement slurry. This device is good for online use in industrial and mining companies. It is especially useful for measuring density in tough, hard, corrosive, hot, and high-pressure conditions.

5. Ultrasonic density (concentration) meter

Working principle:

Ultrasonic density (concentration) meter is based on the transmission speed of ultrasonic waves in liquid to measure the density of liquid.

Theory and experiments have shown that the speed of ultrasonic waves in a liquid depends on its concentration and temperature. Changing the concentration of the liquid will cause the speed of the waves to change as well.

The speed of ultrasonic waves in liquid depends on its elasticity and density. Therefore, changes in the transmission speed at a specific temperature indicate changes in concentration or density.

In this way, when the ultrasonic sensing unit of the meter gives an ultrasonic signal and measures its transmission speed in the process liquid and the current temperature of the liquid, the meter can accurately calculate the concentration, temperature, speed and other related data. The current concentration or density value.


Ultrasonic testing is not affected by the color, dirtiness, or flow of the medium.


The price of this product is relatively high, and the measurement is greatly affected by air bubbles. There are also limitations of its own circuit and environmental interference on the industrial site. The accuracy of this product needs to be improved.

Typical applications:

Industries such as chemical, petrochemical, textile, semiconductor, steel, food, beverage, pharmaceutical, winery, paper, and environmental protection. This sentence is quite long and complex, making it difficult to understand. Let’s break it down into shorter, simpler sentences while still conveying the same meaning and details.

The main purpose is to measure the concentration or density of different substances. These substances include acid-base salts, chemical raw materials, various oil products, fruit juice, syrup, beverages, and wort.

Also, it measures different wines, materials for making wine, things added to wine, oil products, changing how materials are moved, separating oil and water, and monitoring different material parts.

Featured Density Meters

How to Select the Right Density Meter?

How to choose the right density meter? Based on our Sino-Inst’s many years of experience in density measurement. We have sorted out the selection considerations for industrial density meters. Selecting the right density meter requires consideration of the following factors:

1. Measuring medium: What are you measuring? Liquids, gases, or both? Sludge, sediment? Make sure to choose a density meter that is compatible with your sample type.

2. Measuring range: Determine the density range of the substance you need to measure. Different densitometers have different measuring ranges. Make sure to choose an instrument that covers the range you need.

3. Measurement accuracy: Select a density meter according to your accuracy requirements for density measurement. Certain applications need very accurate density measurements, while others can tolerate less accuracy.

4. Use environment: Consider the environment in which you will use the density meter. If you need to measure in harsh conditions. Such as high temperature or high pressure environment, you need to choose a density meter that can work well under these conditions.

5. Functions and characteristics: Density meters may have different functions and characteristics. Choose the functions and features that suit you. Consider things like automatic temperature compensation and data logging and storage.

6. Budget: Finally, consider your budget constraints. Density meters come in a wide range of prices. Choose a cost-effective and reliable density meter according to your budget.

To choose a density meter, refer to the manufacturer’s product specifications and technical parameters. This can help you make more informed decisions and find the right density meter for your needs.


Density meters help figure out how thick or thin a substance is. Industries like food, medicine, and fuel use them to make sure their products are top-notch and safe.

Think of a densimeter as a special scale. It checks how much space a sample takes up and uses that info to tell its density.

It’s often referred to as a “densimeter.” Both names mean the same thing and point to a tool that measures density.

In simple terms, the theory is about measuring how much a certain amount of substance weighs and then figuring out how tightly packed its particles are. This helps determine if the substance is dense (thick) or not dense (thin).

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Understanding density is key for many industries, from food and medicine to fuel. A good density meter, or density meter, helps ensure products are safe and high-quality.

Picking the right one might seem tricky, but with a bit of knowledge, it becomes easier. Remember, every tool has a purpose, and it’s about finding the best fit for your needs.

We, Sino-Inst is a professional density meter supplier. We produce and supply more than 10 kinds of density meters such as tuning fork density meters, differential pressure density meters, and hand-held density meters. Our density meters are exported to various countries, USA, UK, Spain, Ukraine, Nigeria, etc.

If you’re looking for expert guidance or a customized solution, remember we at Sino-Inst are seasoned manufacturers and suppliers here to help. Reach out to us and let’s make sure you get the perfect tool for your tasks!

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About KimGuo11

Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects. Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.