What is RO (Restricted Orifice Plate)?
Restriction plate has an orifice bore (and plate thickness) that is calculated to achieve the required restriction to the flow rate or pressure drop whilst maintaining plate integrity.
A multi-restriction assembly, consisting of several plates in series, can be engineered for use where the required pressure drop cannot be achieved (or where the noise level would be too high) across a single plate.
Types of restriction orifice plates?
Restriction plates and assemblies are available in a wide range of materials to the process.
Single-stage restriction orifice:
A single-stage restriction orifice is usually a plate or a block with a bore (orifice)sized to the intended permanent loss of pressure. It is installed between the pipe flanges. Usually, it is not a thin orifice plate; it is a thick orifice plate.
Single-stage multi-hole restriction orifice:
A single-stage multi-hole restriction orifice plate is used to abate the noise generated by the device due to high velocity through the bore which offers restriction to the incoming fluid. The flow at the inlet is now channeled into several streams through the multiple holes and this reduces the noise which would be otherwise will be above the acceptable limit if a single hole device is used.
Multi-stage restriction orifice plate assembly:
These devices are used where the pressure reduction ratio is very high and cannot be achieved by a single-stage orifice plate. Thus, a multistage device essentially consists of several single-stage devices built in a single spool. As a single-stage device, it can be of single hole multi-stage design or multi-hole multi-stage design or combination of both.
The Restriction Orifices are arranged eccentrically, diametrically opposite each other during the fabrication of MRO.
Application of restriction orifice plates:
The followings are a few examples of common applications where these restriction orifice devices are used to achieve controlled flow from the upstream to the downstream.
- Restriction Orifice (RO) at the downstream of blowdown valves
- Restriction Orifice (RO) in the pump recirculation line
- Restriction Orifice (RO) to restrict gas blow-by
- Restriction Orifice (RO) to excess flow
- Restriction Orifice (RO) for controlled pressurization