What are Flow Restrictor Orifices and how do they work?
Orifice restrictors are flow control devices placed in the line of a pneumatic device that regulates the amount of air passing through it. They are used when a fixed flow rate is required because they cannot be adjusted. By controlling the flow rate, a flow restrictor orifice can be used to control and maintain the speed of a pneumatic device or fluidic process.
How to Control your Device with Orifice Restrictors
In this video, John Hayden uses Air Logic precision molded orifices to control the speed of the Model Corliss Engine. The miniature precision orifices in this video range from .025″ to .040″. Several flow restrictors are tested to find the best orifice size to achieve the technical specifications of the Corliss Engine. The orifice diameters are color-coded based on the flow restriction each precision orifice provides.
Every application is special and requires the right size orifice. Too large of an orifice and the flow rate will be too high, resulting in an over-speed condition. Too small of an orifice and the flow rate will be too low, resulting in an under-speed condition. It is important to select the right orifice size for each application to ensure optimal performance. In the video, a .025″ orifice provides a very low RPM, and a .040″ orifice provides the right amount of airflow for the Corliss engine to work at its rated output.
What are the benefits of using an Orifice Restrictor?
Orifice restrictors are a low-cost alternative to variable flow rate devices. They are less expensive and easier to use than variable flow rate devices, and they provide a fixed flow rate. This makes orifice restrictors an ideal choice for high-volume device manufacturing. Having a reliable method of flow control that is also cost-effective is often one of the application requirements during product design.
Another benefit of using orifice restrictors is that they can help to improve the accuracy and consistency of pneumatic devices. When a fixed flow rate is required, orifice restrictors can help to ensure that the speed of the pneumatic device is consistent from start to finish. This is an important aspect of product design when considering large-scale production. This is especially true if the device is built by a third party and quality control is critical.
How to specify an Orifice Restrictor by Orifice Diameter
When selecting an orifice restrictor for a device, it is important to consider the flow control needs of the device. The size of the orifice restrictor must be matched to the flow rate of the device in order to achieve optimal performance. This can be achieved through calculation or Bench testing. See this video for a bench testing method.
Orifice diameter is the most important factor to consider when selecting an orifice restrictor. The orifice diameter must be matched to the size of the device in order to achieve optimal flow control. Selecting the wrong orifice diameter can result in poor flow control performance and inaccurate device operation.
There are many additional factors that impact the flow restriction of an orifice, not just the orifice diameter. The length and shape of the orifice also play a role in the flow control properties. Long orifices provide more resistance to airflow than short orifices, and sharp-edged orifices provide more resistance to airflow than round orifices. A Precision orifice must control these additional factors to provide flow control in a tight tolerance band.
Can you use a Precision orifice for Flow control of Liquids and Gases?
Flow restrictors can be used to impart flow control on air, gas, or liquids. When a fluid flows through an orifice, the velocity of the fluid is restricted. This results in a decrease in the flow rate of the fluid. The size of the orifice affects the flow rate of the fluid, as well as other factors such as the length and shape of the orifice. Flow restrictors provide the best flow control when the flow rate hits the critical velocity.
The difference in fluid flow performance through a flow restrictor with gas and liquid is the compressibility of the fluid. Flow rates of a non-compressible fluid will plateau after the critical velocity is achieved. With gas, the flow control properties of a flow restrictor are somewhat limited by the compressibility of the gas. So, in both operating conditions, the orifice will regulate flow. However, since gas is compressible, the flow data will continue to rise with increasing pressure, even after the critical velocity has been achieved. In other words, pressure changes will result in small flow measurement changes above the critical velocity.
Orifice Restrictor vs Flow restrictors
Flow restrictors are a general term for any device that restricts the flow of a fluid. They can be fixed or variable and may be controlled mechanically or electronically. Flow restrictors are used in a variety of applications, from controlling the flow rate of pneumatic devices to regulating the flow of liquids.
One common type of flow restrictor is the orifice restrictor. Orifice restrictors are small devices that are placed in the line of a pneumatic device to control the airflow. They are used when a fixed flow rate is required, and cannot be adjusted.
Miniature precision orifices generally have under .040″ orifice diameter. The provided flow control is intended for very low flow rates. Flow control applications for miniature precision orifices are typically table-top size devices or smaller. Precision metering in a small system is one of the flow control applications where a miniature precision orifice is commonly used.
In this video, John Hayden describes the basic needs of a system to control flow rate.
What are some other names for Orifice Restrictors?
Orifice restrictors are also commonly referred to as flow restrictors orifice, flow control orifice, precision orifices, and airflow restrictors. All of these terms refer to the same device: a small device placed in the line of a pneumatic device that regulates the amount of air passing through it. By controlling the flow rate, orifice restrictors can be used to control and maintain the speed of a pneumatic device.
Precision orifices at Air Logic
At Air Logic, we mold precision flow restrictors out of plastic. Our best-selling product line is our molded orifice restrictors. Our Product catalog also includes filtered orifices which have an integrated filter. We manufacture our flow restrictors in-house to ensure that they meet our high standards for quality and precision. Quality begins with the tooling we design and build ourselves, next the molding and quality departments work in tandem to maintain the orifice flow rate during each production run. Flow data is collected on a regular basis and documented to maintain precision.
We also offer custom fabrication services for our clients who need a flow restrictor that is tailored to their specific application. Flow rates and chemical compatibility are common technical specifications for a custom precision orifice.
Since 1975, Air Logic has been serving a wide array of flow control markets with applications from medical applications like ventilators to single-serve coffee makers. Customers across the world trust Air Logic’s precision orifices to control the gas, gases, or fluids in their systems.
Each orifice size starts with a precision-made pin that creates the internal orifice geometry when the plastic is molded around it. The shape of the pin is critical for molding precision orifices. Flow data from the quality department directly influences the maintenance of the mold geometry.
Why use a Model Corliss Engine?
The model Corliss engine is important to our company because our founder built it. He had a passion for miniature things, and the model Corliss engine was one of his smaller hobby projects. Our company still has the model Corliss engine today, and it is on display in our office. We believe that it is important to keep our founder’s legacy alive, and the model Corliss engine is a big part of that.
Let Air Logic Help You with your Next Project.
At Air Logic, we specialize in manufacturing miniature precision orifices that can be used to control the flow rate of liquids and gases. We have a wide range of orifice sizes and shapes to choose from, and we can also fabricate a custom orifice to meet your specific needs. Our precision orifices are made from high-quality plastic and are rigorously tested to ensure accuracy and precision. We have been manufacturing flow restrictors for over 40 years and have a proven track record of excellence. Let Air Logic help you with your next flow control project!
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