An orifice plate is a devices that is commonly used in many industries that need to measure flow rates. The device can also be used to reducing pressure or flow restricting. The last two purposes also relates to the plates that are known as a restriction plate. This device works on the principle of differential pressure measurement.
The device is features the plate with one or more holes and it is placed inside a pipe. The way it works is when the liquid (e.g. gas) passes through the pipeline and reaches the orifice plate it creates pressure and builds up a upstream. In that wat the velocity increases which means that, the flued pressure decreases.
The orifice plates are commonly made with sharp-edged circular orifices. When industries uses this device it will be installed concentric with the pipe and with pressure tappings. Depending on the type of pipe and the need to measuring the flow, there is different types from small to larger orifice plates. Some of the plates are conical or rounded in the edges. It is also possible to install the orifice plate eccentric to the pipe and place pressure tapping in another position.
The tapping points
An orifice plate is a flat circular plate and to measure the flow and there are pressure tapping points – upstream and downstream. Most commonly, there are four methods for tapping point placement, which are pipe tapping, flange tapping, vena contracta tapping and D and D/2 tapping.
The major types of orifice fitting
Single chamber – this kind of fitting consists of a single chamber for accurate measurement.
Dual chamber – this kind of fitting is used when there is installed a conjunction with upstream and downstream.
Double block and bleed – this fitting is characterized by two valves that is used for different chambers.
The industries that use orifice plates
There are a many industries that use orifice plates because there is many possibilities with this kind of device for measuring flow rates. Some of the most commonly industries that uses this device are refineries, petrochemical plants water utility plants and natural gas industries.
The pros of orifice plates
- Easy to use
- Accurate flow measuring
- Installed horizontally or vertically