# What is Flow Meter and what are the types of flow meter?

What is a Gas Flow Meter?

Flow meter is an instrument used to determine the existence of a material flow (liquid, gas, powder) in a pipeline. Namely, the flow rate is calculated by accumulating the total mass or volume of the material flowing in a pipeline within a certain period of time which is often called as totalizer. Parameters of the flow of material are measured using a flowmeter then the measured value is sent in the form of numerical data, it can also be forwarded to generate electricity or a signal that can be used as input to control logic or other electrical circuits.

Flow meter working principle

Coriolis Mass Flowmeter Working Principle

The Coriolis principle states that when a particle in a rotating motion approaches or moves away from the center of rotation, the particle produces an internal force acting on the particle.

Suppose the fluid is flowing into the U-shaped tube at a velocity V and the tube is vibrating at an angular velocity, then by considering a small portion of the fluid at the inlet at a distance r, a force is generated (known as the Coriolis force).

Coriolis Mass Flowmeter Parts

1. Sensor

Temperature sensor, this sensor serves to detect the temperature of the passing stream.

Flow sensor (Coriolis), this sensor serves to detect the amount of flow that passes in the process.

Pressure sensor, this sensor serves to detect the amount of working pressure in the Coriolis meter.

1. Transmitters

This equipment has a function to receive the signal magnitude from the sensor and then convert it into the desired signal and then forward it to the output section.

This equipment is in the form of local indicators that have been adjusted to the wishes of the operator. For example, indicators of the number of flows that have passed or other quantities.

1. Can be used on liquids, slurries, gases, dual-phase liquids, and gas streams (within limits).

2. The unit of measure is in weight, an advantage when the mass measurement is desired.

3. Capable of handling difficult liquids (liquids with various densities) where other meters cannot be used.

4. Provides high accuracy and repeatability in liquid flow and slurries, the accuracy is compared to other meters normally used in liquid flow.

5. Unbound to rotation and flow profile, requires no change in a flow state.

6. Able to measure hot fluid flow (molten sulfur, liquid toffee) and cold fluid flow (cryogenic helium, liquid nitrogen).

7. Pressure drop: low

1. Available only in sizes 1/16 to 6 inches.

2. If volume measurement is desired, conversion via density measurement or analysis under basic conditions is required.

3. Size Line size available: limited.

4. Compared to other flowmeters Coriolis flow meter’s size is large

5. Special installation is required to secure the meter from mechanical vibration

6. Initial procurement cost: high

7. The possibility of clogging occurs and is difficult to clean

There are several factors that can interfere with the working of a flow meter. They are:

• Accidental extra stress in the treatment fluid.

• Electromechanical voltage is intentionally induced in the electrode or liquid.

• Capacitive coupling between signal and power source.

• Inductive coupling between magnetic components in the system.

• Capacitive coupling that binds the intermediate parts.

Types of Flowmeters

There are several types of flow meters based on the type and how it works, they are:

Orifice Flow Meters

This type of flow meter works in principle using a pressure difference and can be used for both high temperature and high pressure.

Orifice Flow Meter besides can be used to measure the flow of liquid, gas can also be applied to the flow of steam. Flow Meters made of UPVC, PE, and PP or PTFE are very suitable for corrosive chemical flow applications. In this type of Orifice Flowmeter, there are also those that are applied to heavy/viscous material fluids such as slides in the WWT process or measuring gases that have high humidity.

Glass Tube Flow Meter

The Glass Tube Flow Meter is widely used for installation applications with vertical systems and the flow rate can be read directly on a glass tube where the glass material is quite good, namely Pyrex glass. This type of Glass Tube Flow Meter is widely used when the fluid pipe installation does not have an adequate horizontal area so it does not really need a large area.

For its application, the Glass Tube Flow Meter can only use maximum at a temperature of 120 degrees Celsius.

Electromagnetic Flowmeter

An electromagnetic Flowmeter is a type of flow Meter that is used to measure fluids in the form of water or other liquids, whether the flow is corrosive, dirty, and muddy.

Electromagnetic flowmeters are the most widely used in water and waste water measurement applications and chemicals. Most of the applications of the use of Electromagnetic Flowmeters are for the industrial world such as the Food, Beverage, Pharmaceutical, Hospitality, and waste treatment industries because they must use a flowmeter that meets sanitary requirements.

Electromagnetic Flowmeters are widely used in liquid measurement applications in the form of liquids and mud, which have electrically conductive properties where the main component of the electromagnetic flowmeter is a flow tube (main element) which is installed by an electric coil both inside the tube and outside the flow tube.

The pressure drop in electromagnetic flowmeters is the same as the flow of liquid through a long pipe, this is because there are no moving parts or obstacles to flow. If the voltmeter is directly installed on the flowmeter tube then it is commonly referred to as a local system or if the voltmeter is installed in another place and is connected by a cable according to the field condition then it is referred to as a remote system.

Magnetic flowmeter in principle uses Faraday’s law of electromagnetic induction. According to this principle, when a conductive medium passes through a magnetic field it will produce a voltage. This voltage is directly proportional to the speed of the conductive medium, the density of the magnetic field, and the length of the conductor. In Faraday’s Law, these three values ​​are multiplied together along with a constant, to produce the magnitude of the voltage. Therefore, the liquid measured by an electromagnetic flowmeter must act as an electric conductor.

Magnetic flowmeter has the main advantage that this electromagnetic flowmeter can measure conductive liquids and corrosive liquids and sludge, and the flow measurement accuracy is quite accurate.

The main limitation for Magnetic flowmeters is that they cannot measure hydrocarbons (which are nonconductive), and therefore are not widely used in the oil and gas, and processing industries.

Coriolis Flow Meter

Coriolis Mass Flow Meters are tools for measuring the mass of liquid moving through a particular tube. It is used in engines, where the fuel will move through the fuel lines where the correct amount of oil has to be calculated and every other system where the exact amount of the substance has to be known. Coriolis mass flow meters measure fluid mass, not volume