9 Key Advantages and Disadvantages of Orifice Meter | Uses of Orifice Plate | Venturi vs Orifice Meter
Advantages and Disadvantages of Orifice Meter | Uses of Orifice Plate | Venturi vs Orifice Meter | Applications And Uses of Orifice Meter
What is Orifice? Orifice Plate & Meter
An orifice plate is a device that is used to measure flow rate, reduce pressure, or restrict flow. It is a type of flow meter that uses the Differential Pressure Measurement concept to measure the rate of flow of a liquid or gas, particularly steam.
It is mostly applied for heavy-duty applications due to its resilience and low cost.
The basic piece of the instrument is an Orifice Plate. When this Orifice Plate is mounted in a line, it creates a differential pressure across the Orifice Plate.
This pressure drop is linear and proportional to the liquid or gas flow rate. It can measure volumetric flow rates, and it works on the same basis as a venturi meter, which is Bernoulli’s principle.
The principle which states that the pressure and velocity of fluid are related, so that if the velocity increases, the pressure decreases, and vice versa.
The flow is measured using an orifice plate, which can reduce or restrict the flow. The orifice plate will be fitted between the two pipe flanges, and the proper pressure connection will be made as well.
Orifice plates are employed in a variety of fluid and operating conditions applications. It is inexpensive and does not require routine maintenance.
Applications and Uses of Orifice Meter
1. Water treatment plants
Orifice meters are used to measure the runoff flux from a water treatment plant. Flow is measured as the amount of water passing through an orifice meter and converted to a value of discharge by comparison with known flow.
Once measured, the flux and its relation to available energy can be calculated for each unit of flow.
Orifice meters are used at wastewater plants for measuring the flux coming from disposal tanks and sent downstream for further treatment.
2. Natural gas industries
The natural gas industries use orifice meters to measure the flow of natural gas through a particular pipeline.
3. Hydropower plants
Hydropower plants use orifice meters for measuring water flow rate and discharge for efficient operation.
The main objective of the industry is to ensure that water is not wasted in any stage during production.
Orifice meters are used in hydropower plants for measuring water exiting the penstock and the speed at which it travels before reaching the turbine, thus enabling the plant to produce efficiency
Refineries use orifice meters for measuring the oil and gas flow rate and discharge from the pipeline
The orifice meters allow refineries to efficiently control the operation of their facilities, optimize production and maintain a healthy balance between stock and demand.
5. Chemical industry
Chemical industries use orifice meters for measuring flow of fluids, gases, steam etc. through pipelines used in chemical plants for efficient operation and high production of chemicals.
6. Petrochemical plants
Petrochemical plants use orifice meters for measuring flow rate and discharge of hydrocarbons and other liquids through pipelines used in the chemical industry.
The measurements of the flow rate of fluids, gases, and steam are vital to use in plants that produce such gases used in different industrial processes.
Difference Between Venturi Meter and Orifice Meter
A venturi meter is a more expensive way of measuring the rate of flow of fluid through a pipe. An orifice meter is a less expensive way to measure the rate of flow through a pipe.
A venturi meter has lower energy losses, whereas an orifice meter has higher energy losses.
When compared to an orifice meter, a venturi meter has a high coefficient of discharge.
A venturi meter is more difficult to make than an orifice meter.
A venturi meter takes up a lot of room, whereas an orifice meter takes up a lot less.
Types of Orifice Plates
The typical designs of orifice plates are:
- Concentric orifice plate
- Eccentric orifice plate
- Segmental orifice plate
- Quadrant edge orifice plate
Examples of Orifice Meter
Orifices are used to regulate the flow of fluids such as air. There are certain physics and/or engineering aspects involved that are taught in Physics class, but to cut a long story short, without the use of orifices in the spray nozzle, the nozzles on garden spray hoses would have relatively weak spray output.
Here are some typical examples:
- Spray nozzle for a garden hose
- Spray nozzles for paint
- Gas tips for welding equipment
- Faucets in the kitchen
- Showers Heads
Advantages And Disadvantages of Orifice Meter
Advantages of Orifice Meter
What are the advantages of an orifice meter?
1. Low cost and simple construction:
Office meter requirements are the most basic measurement of flow of fluid. It can be used in both industrial and domestic applications.
The most significant advantage of an orifice meter over others is that it can be easily installed without requiring any special tools
. A technician who has a basic knowledge of electricity supply and installation procedures can install an orifice meter on site. It could be connected to the power supply through a plug and socket arrangement.
3. Supply cost:
It does not require any complex equipment and hence is comparatively less expensive than other types of meters.
4. It would only occupy a small space:
An orifice meter does not need a large space – its installation can be done in the office itself. Besides, it does not require a lot of technical knowledge which can be easily acquired by any technician through appropriate training and experience.
5. Field service:
An orifice meter is easy to use and operate even in the field. Again, regular maintenance is not needed
6. It is available in any size:
An orifice meter can be ordered in various sizes to suit the requirements of the users.
7. Easy calibration:
Orifice meters are easy to calibrate. Even a technician who does not have any background in engineering can easily calibrate an orifice meter by reading a chart provided with the equipment.
Orifice meters are commonly calibrated with standard fluid such as water by using liquid gas, oil etc..
9. High Accuracy level:
Orifice meters are highly accurate. The finished calibration measurement is obtained within the specified tolerance.
The tolerance levels of an orifice meter are given as A, B and C. The higher the accuracy and precision, more the value of A, B and C
10. Easy Maintenance:
Orifice meters have a very low maintenance requirement when compared to other types of flowmeters. Orifice meters do not require regular adjustments, periodic cleaning, lubrication and calibration. Their life span is very long which reduces the need of maintenance
Disadvantages of Orifice Meter?
1. Pressure loss and clogging:
The main drawback of an orifice meter is its pressure loss which results in a decrease of the measurement accuracy.
It can also be clogged by particulate matter present in the fluid. When an orifice meter is not calibrated, it would produce wrong output readings.
2. It cannot be used for non-Newtonian and highly viscous fluids:
Since orifice meters are not designed to work for highly viscous fluids, they are not very suitable for those fluids like tar, asphalt etc..
3. Poor downstream pressure recovery:
An orifice meter has poor downstream pressure recovery when compared to other types of meters.
Some orifice meters might have higher downstream pressure recovery than others, but it is not very significant as compared to the upstream pressure.
3.. It cannot be used for transient flow:
If the fluid has high viscosity, then it would not be suitable for transient flow and could produce high outputs on test results.
The most common fluid that would result in low output in case of transient flow is tar.
4. Its allowable pressure drop is very high:
An orifice meter has a very high allowable pressure drop. The allowable pressure drop level for an orifice meter is three times the maximum pressure of the fluid being measured.
Orifice meters can be easily clogged by particulate matter present in the fluid resulting in a decrease of accuracy.
5. Plate corrosion is possible:
An orifice meter is mainly made up of metallic parts which are prone to corrosion. The metal used in an orifice meter has to be properly treated for corrosion resistance prior to its installation.
6. It does not provide any drag loss:
An orifice meter cannot be used in the presence of a drag resistance that causes a reduction in measurement accuracy.
This is because the opening of an orifice meter is aligned with the flow direction, which would prevent any friction loss caused by a drag resistance.
Orifice Meter FAQs
1. What is the purpose of an orifice?
An orifice plate is a device used to measure flow rate, reduce pressure, or limit flow; in the latter two circumstances, it is also known as a restriction plate.
2. What is the function of the orifice plate?
It is a device used to measure flow rate, reduce pressure, or limit flow; it can also be described as a restriction plate.
It is used in many applications because it costs little and does not require routine maintenance. The basic piece of the instrument is an Orifice Plate.
3. How is the orifice plate installed?
The orifice plate is installed in a pipe, so as to create a differential pressure between it and its surroundings.
4. What are the details of steam traps?
Steam traps are a sort of automated valve that filters away condensate (condensed steam) and non-condensable gases like air while allowing steam to escape.
Steam is often used in industry for heating or as a driving force for mechanical power.
The purpose of a trap is to prevent the passage of non-condensable (i.e., combusted) gas and water vapour into a pipe, preventing its subsequent combustion within the test chamber.
5. What are the applications of an orifice meter?
Orifice Meters are used in a variety of fluid and operating conditions applications. It is inexpensive and does not require routine maintenance.
6. What are the qualities of the Orifice Meter?
An orifice meter may be defined as a device used to measure both volumetric and mass flow rate of fluids by measuring the pressure drop across an orifice plate
According to its use, it is further classified as velocity type or differential type.
7. What are the types of orifice?
According to the basic shape, orifice plates are of three types: circular, rectangular, and oval. According to its use and application, it could be single or multi-jet type.
8. How is an orifice plate measured?
The flow rate across a plate, is determined by measuring the pressure drop across the plate. The pressure drop varies directly as square of velocity and inversely as cross-section area of flow passage.
9. Which is better venturimeter or orifice meter?
The venturimeter is more accurate than the orifice meter but it’s difficult to calibrate and use in applications like ventilation tests.
On the other hand, the orifice meter is simpler and easier to use; however, it has lower accuracy rates compared with the venturimeter.
One thing they have in common: both of them are used by engineers and technicians when testing ventilation systems.
Many people feel that the venturimeter is superior because it’s more accurate and can be used more often. Others argue that the orifice meter is more cost effective and requires less training to use.
10. How are velocity-type orifice meters measured?
Velocity type orifice meter uses a pitot tube network. The pitot tube measures the pressure loss across the plate and variations in these pressure losses related to changes in fluid velocity.
The device converts this measurement into mass flow rate and displays it on a digital display instrument.
11. What are some examples of orifice?
1. Oil and gas measuring system.
2. Steam and gas metering systems.
3. Fluid Meters are used in a variety of fluid and operating conditions applications. It is inexpensive and does not require routine maintenance
12. What is the difference between the orifice plate and restriction plate?
An orifice plate is an instrument that can restrict the flow of a liquid by restricting the flow passage (opening).
Orifice plate is an orifice used for measuring flow rate, reducing pressure or limiting flow. For the application of a steam trap, it is commonly known as a back pressure device.
13. What are the advantages of Orifice Meter over Restriction Plate?
• Must use off-the-shelf components and stainless steel in the construction
• Simple operation and low maintenance
• Fast response time to changes in valve positions — same as for a manometer
14. What is a check valve?
A check valve is a one-way valve used to prevent flow flowing back into a system.
15. What are the types of Check Valves?
The different types of check valves are as follows:
1. Unsealed Check Valve (also known as Cullet).
2. Auto close check valve (also known as an “overlap” valve) is a type of check valve that opens by the application of pressure and closes when the pressure is relieved.
3. Pressure Relief Check Valve
Pressure-Relieving or Safety Valve is used to prevent the upstream pressure from exceeding the set point. These valves are used in many industrial process applications to discharge a safety relief valve of condensate or any non-condensable gas that builds up in a piping system upstream of this device.
16. What is the difference between orifice and mouthpiece?
Orifce and mouthpiece are the two types of check valves used in steam traps and other related applications.
Orifice is a one-way valve by which pressure is applied to liquid flow between pipe lines through an orifice plate.
On the other hand, mouthpiece is a flow control device that can restrict or open the flow of fluids through a pipe line.
17. What are the Advantages of mouthpiece over orifice?
• Faster response time
• Less expensive than other types of check valves
18. What are the disadvantages of Mouthpiece?
1. It requires more manual adjustment to keep it working properly
2. It has a larger pressure drop than other types of check valves
19. What is the difference between orifice and needle?
The orifice valves and needle valves are the two types of flow control devices. Both are used as flow control in fluid systems.
The orifice valve has an opening that restricts fluid flow, which is similar to the needle valve in its use. The needle valve has a needle that is opened and shut with the help of a lever.
20. What are orifice plates?
Orifice plates are in form of plates or discs that have defections or holes on their surface. These types of plates can be single or multi-jet type depending on the application required.