What is Orifice Valve: Complete Guide

orifice valve

If you’re in the industry of measuring and controlling fluid flow, an orifice valve is an important type of flow metering that requires knowledge and proper shop understanding.

This type of valve is used to measure the rate of water and can even be used to determine gas, steam, and liquid levels at a given point.

An orifice valve essentially consists of a pipe with a small hole inside, allowing pressure drop on either side to provide measurements.

It requires careful selection as they come in varying sizes and types to ensure accuracy.

Plus, specific conditions need to be followed during installation to work properly.

In this guide, we’ll go through what exactly an orifice valve is for, various types of orifice valves, and how it helps your business when dealing with fluid flows.

Orifice Valve Construction

To accurately measure the flow rate, it is crucial to construct the orifice meter properly. This section walks through each step of constructing an orifice meter for your project.

Inlet Section

The inlet section extends from the device and consists of a linear segment ranging from 2” to 8”. 

This linear segment must be perfectly straight with no bends or curves, as these would affect the accuracy of your measurements.

A flow conditioner should also be installed in this section to reduce turbulence and ensure accurate readings.

Outlet Section

The outlet section is similar to the inlet section; it should consist of a linear segment with no bends or curves, ranging between 2” and 8”, depending on your project needs.

Orifice Plate

The most important part of constructing an orifice meter is ensuring that you have the correct size orifice plate for your project.

This plate should be made of stainless steel and must fit securely between your inlet and outlet sections without any gaps.

It is also imperative to ensure it has been machined correctly, as any imperfections could affect how accurately it measures flow rate.

Differential Manometer

Finally, you will need a differential manometer measuring the difference in pressure between two points to calculate the flow rate.

This device should be connected directly to your orifice meter to measure changes in pressure across the plate accurately.  

Working Principle Of Orifice Valve

An orifice valve consists of two concentric rings with an opening between them, known as an orifice.

When the valve is closed, there is no flow through this opening and, therefore, no pressure difference between the two rings.

However, when the valve is opened, fluid flows through the orifice and causes a decrease in pressure on one side of it.

This decrease in pressure can be measured and used to calculate the flow rate of the fluid.

Video – Variable Orifice Operating Principles

Applications Of Orifice Valve

Orifice valves are one of the most frequently used engineering components due to their diverse applications in various industries.

Flow Control

Orifice valves are used to control flow rates in industrial processes.

They can regulate the amount of liquid or gas passing through a pipe by controlling its pressure, allowing for greater control over operations.

This makes them particularly useful for operations where safety is a priority, such as those involving hazardous materials.

Temperature Regulation

Another application for orifice valves is temperature regulation.

By regulating the flow rate of a material through a pipe, its temperature can be controlled more effectively.

This helps improve efficiency and prevents potential damage caused by sudden changes in temperature.

Orifice valves are particularly effective when used with heat exchangers and other devices designed to maintain temperatures within an acceptable range.

Pressure Regulation

Finally, orifice valves can also regulate pressure levels within pipes and other systems.

Controlling the amount of material flowing through a given pipe at any given time, it’s possible to prevent pressure spikes which could lead to serious issues with equipment or machinery downstream from the valve itself.  

Advantages and Disadvantages

Let’s take a closer look at the advantages and disadvantages of an orifice meter.

Advantages of an Orifice Meter

  • It’s cost-effective and quite easy to use. This makes it ideal for applications where accuracy is less important than price.
  • Additionally, it occupies less space than other flow meters, making it ideal for space-constrained applications.
  • It can also determine flow rates in large pipes; this makes them suitable for a wide range of applications.
  • It can be installed in horizontal or vertical positions; this allows for greater flexibility when installed in tight spaces.
  • They offer high accuracy levels compared to other flow meters.

Disadvantages of an Orifice Meter

Unfortunately, there are also some potential drawbacks to using an orifice meter.

  • Since orifice meters measure pressure drop across the device itself, they can create significant pressure loss within the system over time which could lead to clogging issues if left unchecked.
  • Additionally, they cannot be used for non-newtonian fluids like sludges or highly viscous fluids like molasses due to their inability to measure these types of liquids accurately.
  • Because of their design, they need to provide better downstream pressure recovery.
  • Any changes made upstream will drastically affect the downstream pressures in your system, which could cause issues with your equipment if not monitored closely enough.

How To Remove Or Installing Orifice Valve

While installing or removing an orifice valve may seem intimidating, it is relatively straightforward.

We will discuss how to install and remove an orifice valve in detail so you can confidently take on the job.

How to Install an Orifice Valve

Before beginning the installation process, you should ensure you have all the necessary tools and materials.

You will need an adjustable wrench, a ratchet wrench set, a pipe wrench, Teflon tape, thread sealant, and some pipe compound.

Once you’ve gathered everything, follow these steps to install your new orifice valve:

  1. Turn off the water supply before starting the installation process. This is incredibly important for safety reasons.
  2. Take apart the faucet’s connection pieces by loosening them with a pipe wrench and then unscrewing them with your adjustable wrench.
  3. Make sure to track which screws go where for easy reassembly later.  
  4. Wrap Teflon tape around the threads of the new orifice valve twice before inserting it into place. This will help create a tight seal that prevents leaks from occurring once everything is reassembled later on.  
  5. Apply a small amount of thread sealant onto each screw before screwing them into place with your adjustable wrench.
  6. Then tightening them with your ratchet wrench set until they are secure but not too tight (as over-tightening can cause damage to the pipes).  
  7. Finally, apply some pipe compound around each joint before reassembling everything and turning on the water supply.  

How to Remove an Orifice Valve

Removing an existing orifice valve is just as easy as installing one—all it takes is a few simple steps!

Make sure you have all necessary tools and materials mentioned in the installation process ready before beginning this process:  

  1. Turn off the water supply before starting this process for safety reasons—this should be obvious.
  2. Take apart any connections at either side of your existing orifice valve using your adjustable wrench (for smaller fittings) and your pipe wrench (for larger fittings).
  3. Again, keep track of which screws go where for easy reassembly later if applicable (in case you decide not to replace your current orifice valve but rather just want to repair it).    
  4. Once all connections have been removed from either side of your existing orifice valve, unscrew it from its position using a combination of both wrenches until it comes loose from its seat.
  5. Carefully lift out from its mounting location, taking care not to scratch anything in its vicinity while lifting out due to its sharp edges depending upon what material was used when manufacturing/installing originally.     
  6. Once removed, thoroughly clean out all debris left behind after removal using appropriate cleaning materials like steel wool/scrubbing brush/etc.
  7. Finally, wrap Teflon tape around threads before proceeding to the replacement phase mentioned in the “Installation” section above.

Installation Conditions Of Orifice Valve

Before you start, it’s essential to understand the requirements for installation and ensure that your pipeline is prepared for installation.

Here are the six main requirements for orifice valve installation straight run requirements.

Measuring Pipe Section

The section of the pipe where the orifice plate is installed should be as straight as possible.

The length of the straight measuring section should be at least three times the inside diameter of the pipe itself.

This helps ensure that measurements are accurate and reliable.

Gate Valve Selection and Operation

When installing an orifice plate, select a gate valve with a good sealing performance that can open and close quickly and reliably.

During operation, keeping the gate valve open is important to reduce pressure losses in the system and get accurate readings from your orifice plate measurement device.

Inner Diameter Impulse Pressure Pipeline

The inner diameter of the impulse pressure pipeline should be determined based on two factors: the pipeline’s length and how much contamination is present in the medium being measured.

Longer pipelines will require larger diameters, while more contaminated media will require smaller diameters to ensure accuracy during measurement.

Horizontal Section of Pressure Pipe

To achieve maximum accuracy when measuring liquid flow rates, all horizontal sections of pressure piping should be in one single plane when installed around an orifice plate meter.

This ensures that all elements are properly aligned before taking measurements.

Firm Support for Pressure Piping

As part of installing an orifice plate into your pipeline, it’s important to ensure adequate support is provided for all pressure piping components.

Any shifting or vibration can cause inaccurate readings from your flowmeter, so ensure enough support throughout your system to avoid these issues.

Maintaining Single-Phase Flow State

Finally, it’s important to remember that a single-phase flow state must always be maintained for the proper operation and accuracy of your orifice plate meter device.

When possible, install strainers upstream of any multi-phase flows that could negatively impact performance over time if left unchecked.

Maintenance Of Orifice Valve

Checking it regularly can reduce the risk of corrosion or wear, which could cause it to malfunction.

It is recommended that you flush out any possible contaminants collected in the orifice whenever possible.

Also, check for any signs of deterioration, such as discoloration or leaks.

Additionally, if the valve needs repair, it may pay off to have it inspected by a professional who can help prevent further problems.

Orifice Valve Identification Symbol

The orifice valve identification symbol looks like a circle with two lines and can be found on the end of the valve.

This symbol is used to identify the type and size of the orifice valve, so it is important to ensure you have selected the correct one for your application.

It should also match up with existing plumbing to ensure your system runs properly.


That’s it! Here’s the complete guide on Orifice valves. You might now have a better picture of how they work. And, if you’re looking for some orifice valves, get in touch with the Inoxcnvalve.

We at INOXCN specialize in designing and manufacturing the best-quality orifice valves for various applications.

Our range encompasses orifice valves to meet your exact requirements.

With decades of experience in the industry and rigorous testing standards, you can rest assured that our products are of the highest standard.

Our valves are designed to provide maximum performance and reliability for years to come.

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