A liquid flow metering system is the equipment used to measure the quantity of fluid flowing in a given area. It is often used in water resources to monitor and control water distribution.
This article will discuss the various components of a liquid flow meter and how it works to measure the flow rate accurately.
The Working Principle of Liquid Flow Meter
The heart of a liquid flow meter is the metering orifice. It is a small hole in the pipe through which the fluid flows. Around the perimeter of the orifice are sensors that measure its diameter.
As the fluid flows through the orifice, it causes it to expand and contract. This expansion and contraction are converted into an electrical signal by the sensors. This signal is proportional to the flow rate of the fluid.
The metering orifice must be accurately machined to produce an accurate signal. The size and shape of the orifice affect the accuracy and range of the meter.
Types of Liquid Flow Meter
1. Positive Displacement Flow Meters
Positive displacement meters measure the volume of fluid that passes through the meter. They are often used for measuring high-volume flow rates. The most common type of positive displacement meter is the piston meter.
2. Differential Flow Meters
Differential meters measure the difference in pressure between two points in the flow stream. This type of meter is often used for measuring low-volume flows. The most common type of differential flow meter is the orifice meter. It consists of a metering orifice and two pressure sensors, one upstream and one downstream of the orifice.
The orifice meter is the most common type of flow meter because it is relatively inexpensive and easy to use. It can be used to measure both liquid and gas flows.
3. Velocity Flow Meters
Velocity meters measure the velocity of the fluid as it passes through a tube. They are often used for measuring high-speed flows.
There are two types of velocity flow meters:
- a) Pitot Tube Flow Meter
The pitot tube is a velocity meter consisting of a tapered tube inserted into the flow stream. The velocity of the fluid is measured by the pressure differential between the inside and outside of the tube.
- b) Venturi Tube Flow Meter
The venturi tube is a type of velocity meter that consists of a narrowing in the pipe. The decrease in pressure measures the velocity of the fluid as it flows through the narrowing.
4. Open Channel Flow Meters
Open channel flow meters measure the flow rate in open channels, such as rivers and canals. They consist of a weir placed across the channel and a flume attached to the weir. The water level in the flume is used to determine the flow rate. The most common type of open channel flow meter is the flume meter. It consists of a U-shaped tube with a notch in the bottom. The water level in the flume is used to determine the flow rate.
5. Mass Flow Meters
Mass flow meters measure the mass of fluid that passes through the meter. They are often used for measuring high-volume and high-speed flows.
There are two types of mass flow meters:
- a) Coriolis Mass Flow Meter
The Coriolis mass flow meter is a type of mass flow meter that uses the Coriolis effect to measure fluid mass.
- b) Thermal Mass Flow Meter
The thermal mass flow meter is a type of mass flow meter that measures the heat flux from the flowing fluid.
6. Open Channel Flow Meters
Open channel flow meters measure the flow rate in open channels, such as rivers and canals. They consist of a weir placed across the channel and a flume attached to the weir. The water level in the flume is used to determine the flow rate. The most common type of open channel flow meter is the flume meter. It consists of a U-shaped tube with a notch in the bottom. The water level in the flume is used to determine the flow rate.
Applications of Liquid Flow Metering System for Water Resources
Liquid flow meters are used in a variety of applications, including:
- i) Water resources management
- ii) Irrigation systems
iii) Process control systems
- iv) HVAC systems
- v) Breweries and distilleries
Conclusion
A liquid flow meter is an essential component of numerous industrial and commercial applications. They assess liquid flow rate in various systems, including water resource management, irrigation, process control, and HVAC. Several varieties of liquid flow meters are available, each with its own set of pros and limitations. The liquid flow metering orifice is the heart of a liquid flow meter. The fluid runs through a small hole in the pipe. Sensors around the orifice’s perimeter detect its diameter.