Sintered Filter Technical Specifications

The dull side faces the flow. Every disc, every application, no exceptions.

Temperature and pressure, do not exceed

The pressure rating applies to the clamp assembly. The differential rating is the most pressure difference allowed across the disc itself.

Orientation: dull side toward the flow

A sintered disc is not the same on both sides. The shiny face is built from coarser wire and has the larger pores. The dull face is built from much finer wire and has the smaller pores. Cut a disc in cross section and the pore structure is funnel shaped: the shiny face is the wide mouth of the funnel, the dull face is the narrow throat.

Flow into the shiny side and solids follow the taper inward. Oleoresin, wax and CRC media are carried down the funnel and wedge into the narrowing channel. They are now inside the media, not on it. You cannot brush that out, the filter never comes fully clean, and it clogs sooner on every run after that.

Flow into the dull side and nothing gets in. The smallest openings are the first thing the material meets, so the solids stop at the surface as a cake. Brush it off, ultrasonic it, blow it back out the same fine face that caught it, and the filter is clean.

• Filtering oleoresin: dull side up, facing the incoming flow.
• Adsorptive scrubbing media such as T-41 activated bleaching clay or 10 percent activated carbon: dull side up here too. The media never sits straight on the disc. A perforated plate goes above the disc, filter paper on the plate, then two drop-in rings, then the media. The plate is what carries the paper, and paper laid on an open disc has nothing to sit on and tears through under differential pressure.
• In-line material filtration: pick sizes per need, 25 µm, 10 µm and so on, dull side facing the incoming material.
• Stacking: step down in micron rating in the direction of flow, for example a 5 µm disc followed by a 1 µm disc. Every disc in the stack is oriented individually, dull side toward the flow, not just the top one.

Measured: what the wrong side costs you

The same used discs, flow tested with each face toward the water before cleaning. One U.S. gallon, average of 1 to 9 trials each.

Times in minutes:seconds per gallon. N.B. Oler filter flow testing, 2023.

Recommended micron rating by position

The CRC stack is your call. We run 5 over 1 at the outlet and a 10 on top, but any mixture of 10, 5, 2 and 1 works as long as the rating steps down in the direction of flow and every disc goes in dull side toward the flow. The discs are only half of the stack: the full build order for both columns, with a diagram for each, is in How to Stack a Material Column and a CRC Column. Sintered filters are cleaned, not replaced. Keep a second full set so one set runs while the other is in the ultrasonic bath.

Gasket material compatibility

A: excellent. B: good, minor effect. C: fair, not for continuous use. D: severe effect, do not use. Room temperature ratings, conservative value printed where published charts disagree. Full matrix and temperature limits in REF-CM-01 Chemical Compatibility.

Cleaning procedure

• Rule of thumb: if the filter will not flow solvent at 15 psig (about 2 atm), it is clogged. Stop and clean it.
• Best performance: clean after every run, before it ever clogs.
• Excessive clogging? Stack larger micron filters above the sintered filter to catch big particles.

Failure to follow the recommended cleaning procedure may void your warranty.

With a bath ultrasonicator (preferred)

1. Cease operation of the relevant instrument.
2. Equalize pressure up and downstream with atmosphere, gently, under 0.1 psi per second, by controlled venting or dry nitrogen.
3. Remove the filter.
4. Gently brush off debris with a nylon or soft metal (brass) brush, never harder than stainless.
5. Ultrasonicate in a 304/316 stainless compatible lab detergent such as Alconox, per the detergent maker's procedure.
6. Blow out with clean compressed air or nitrogen against the direction you flowed media, so debris exits back out the same dull face that caught it.
7. Repeat steps 4 to 6 as needed.

Without an ultrasonicator

1. Cease operation and equalize pressure as above, under 0.1 psi per second.
2. Remove the filter.
3. Soak in Alconox or a similar 304/316 compatible detergent for 5 minutes.
4. Gently brush off debris with a nylon or brass brush. Welding shops and gas suppliers carry them.
5. Blow out with clean compressed air or nitrogen against the direction you flowed media.
6. Repeat as needed.

Isopropyl alcohol, deionized water or both work for light cleaning instead of detergent.

Flow rate data, clean discs

Minutes:seconds for one U.S. gallon of cold tap water. If your disc is at or faster than the table, it is clean and ready to use.

How flow rate was tested

• 6" sight spool, caps over the sight glass holes, disc clamped at the bottom on Buna gaskets, raised a couple of inches for drainage.
• Pour 1 U.S. gallon of cold tap water onto the filter and time from first contact until no visible puddle remains. Discs were tested dull side up, the same orientation used in operation.
• For small microns, pour slow and steady to hold a consistent water level. Filters may slow with additional gallons, depending on your local water.
• Test filters were cleaned 20 minutes per side in a 50°C (122°F) ultrasonic bath with 8 to 12 tablespoons of Alconox.

What to buy for this

Sintered tri-clamp filter discsDiscs in the micron rating for each position.PTFE envelope gasketsFor any joint that sees chiller or LCO2 temperatures.Perforated plate with drop-in ringsSits above the disc and carries the filter paper.

Need it built to your drawing? Request a quote

Sources. N.B. Oler Sintered Filter Tech Specs, Rev. 2026.2; N.B. Oler Hydrocarbon Operators Manual, Rev. 2026.2, sections 5 and 6; N.B. Oler filter flow test data (2023); 3P Certz DCR-200101-R1. Alconox, Inc., Alconox Technical Bulletin (2018). Cole-Parmer Chemical Compatibility Database. Omegasonics, Ultrasonic Cleaning 101. Gasket ratings per N.B. Oler REF-CM-01 (Parker, Trelleborg, Chemours, ISM).