Tri Flo Tech orifice plates or RTJ plate holders installed in a line create a pressure differential as the fluid flows through it. This differential pressure is measured via Orifice flanges by a differential pressure transmitter which converts it into an analogue or digital signal which can be processed to provide a display of the instantaneous rate of flow.
The relationship between the rate of flow and the differential pressure produced is very well understood and is fully covered by comprehensive national standards. The relevant standards are BS 1042 or ASME fluid meters and the equivalent ISO 5167. One of the principle advantages of orifice plates manufactured and installed following these standards is that they do not require calibration.
This means that orifice plates are very cost effective on larger line sizes.Tri Flo Tech can manufacture orifice plate,flanges and unions in Carbon steel,St Steel, Hastteloy C,PVC and many other materials.
Types and Features of Orifice Plates
Orifice plate is a device for measuring volumetric or mass fluid flow rates. When it obstructs the flow of a fluid, a differential pressure is produced across the plate. Flow rate is determined based on the difference between pressure readings in the upstream side and the downstream side of the pipe. Different types of orifice plates are used for continuous measurement of fluid flow in pipes. In this article, we will take a look at their features and common types.
The Different Types of Orifice Plates
There are mainly three types of orifice plates available. Let’s take a close look at these three types.
- Concentric – These are most commonly used in pipes below six inches for measuring flow rate of gases, liquids, and steams. The beta ratio of this type of orifice plates ranges between 0.20 and 0.70 for gases and steam, and between 0.15 and 0.75 for liquids. The ratio of the orifice bore to the internal pipe diameters is referred to as the beta ratio.
- Eccentric – They are commonly used for measuring flow rate of fluids containing solids, oils containing water and wet stream.
- Segmental – These are commonly used for colloidal and slurry flow measurement. The positioning of these orifice plates depends on the type of fluid used in the pipe system. Depending upon fluid type, these plates may either be placed on top or at the bottom of a horizontal pipe. These types of plates function quite similarly as concentric orifice. They are known to offer accuracy in measurements.
Features of Orifice Plates
Given below are some major features of orifice plates.
- They are user friendly and simple to install.
- They can be used for almost all kinds of applications.
- They are less costly than several other flow rate measuring devices.
- They come with a thickness of approximately 1/16 to 1/4 inch.
- Pressure loss usually depends on the area ratio. In general, orifice plates have medium pressure loss.
- They usually offer an accuracy of 2 percent to 4 percent of full scale.
- For best results, it is often recommended to use them in pipe systems made of stainless steel.
- They offer a turndown ratio of less than 5:1.
- Viscosity effect is high in Orifice plates.
- They offer better accuracy at high flow rates.
- They are available for all pipe sizes.
For best results, one should use high quality orifice plates from reputable brands. One good idea would be to compare among several items before placing an order.
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