Restriction Orifice Paddle Plates
Single and Multi Hole
Restriction orifice plates are used as a means of controlling line pressure in systems using pressure critical components and are placed in-line using orifice flanges. By nature of their design, Restriction Orifice plates create a large differential pressure and in turn provide the required downstream pressure.
The restriction orifice is calculated and designed taking into account the medium characteristics, the pressure loss and the process data.
There are conditions that need to be considered to ensure a single plate will be sufficient for reaching the required pressure reduction;
Noise – An industry acceptable figure for the noise generated for a single hole restriction plate is <85dB. Noise levels can be further reduced by approximately 5 dB if a multi-hole plate is used. By increasing the number of bores in the plate the noise level generated by the restriction will be reduced.
The maximum acceptable noise level depends on the
installation and service conditions. It is recommended that
the upper limit for the noise level is defined by the health
and safety requirements applicable to the plant (usually
85 dB(A) for continuous operation).
Cavitation – Thick Plate for cavitating flow. The only way to
avoid the cavitation is to change the process parameters
or to use thick single plates. Alternatively the use of
several plates to reduce the pressure in several steps
can be employed. The number of steps is related to the
operating conditions of the plant.1
Sonic flow and choke flow conditions – Single plates
are only acceptable for use if the maximum differential
pressure generated to achieve pressure reduction do not
induce sonic or choked flow conditions.
Features
| ORDERING INFORMATION | Part number format for ordering is as follows; TYPE-SIZE-ANSI-THK-BORE-MTL |
| Size | 0.5” – 24” (other sizes available upon request) |
| ANSI | 150, 300, 600, 900, 1500 & 2500 |
| Orifice bore type | SQC = Square edge concentric, BI = Bidirectional, 1/4 = Quarter circle |
| Bore | ‘d’ dimension in inches (provided by customer or sized by calculation) |
| MTL | 304 = 304 St. Steel 316 = 316 St. Steel D = Duplex SD = Super Duplex M = Monel I = Inconel |
| WORKED EXAMPLES | |
| STRFROP-4-900-0.250-0.5-316 | RF Restriction Plate 4” 900 ANSI, 1/4” thick with 0.5” bore in 316 St. Steel |
| STRTJROP-6-1500-0.500-M-M | RTJ Restriction Plate 6” 1500 ANSI, 1/2” thick with multi hole bore in Monel |
plates are installed into a welded multi-step spool. See our Multi-plate Spool Restriction Orifice datasheet.