Filters and Assemblies

Apex offers a variety of filter assemblies, with 2-, 3- and 4-inch sizing options, along with a variety of filter supports and clamps.

Filters Assemblies

Apex offers a variety of filter assemblies, with 2-, 3-, and 4-inch sizing options, along with a variety of filter supports and clamps.

Filter Assembly 1 — **OZ Filter Assembly Clamp Styles**

Filter Assembly 2 — **Aluminum Filter Assembly Clamp Styles**

In Stack Filter Assemblies

Stainless Steel In-Stack Filter Assemblies

The Stainless Steel In-Stack Filter Assembly is designed to provide a positive seal against leakage from the outside or around the filter. The thimble filters are made of seamless borosilicate microglass fibers with an efficiency greater than 99.95% for 3-micron particles. We also offer quartz silica fiber thimble filters.

Glass In-Stack Filter Assemblies

The Glass In-Stack Filter Assembly is constructed completely from borosilicate glass for use with the conditional method for ammonia (CTM-027) and accepts tapered 25 x 90mm thimbles, specifically manufactured for stack sampling. It does not require O-Rings or grease for testing at higher temperatures. The borosilicate glass withstands temperatures up to 480°C (900°F).

Integrated In-Stack Filter Assemblies

The SGFA-47NK In-Stack Filter Assembly Kit features the unique design combination of borosilicate glass 47mm filter inlet with an integrated nozzle, allowing the option to weigh the glass fiber filter media individually for Method 17, or similar to Method 5I by weighing the combined nozzle & filter media with a support, O-Ring, and PTFE tape. The kit includes the standard array of seven nozzle sizes from 1/8” to 1/2”.

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Filter Media

Apex Instruments offers a wide range of filter media to meet any sampling requirements.

Glass Fiber Filters

PTFE Filters: PTFE Filters Membranes are produced of pure PTFE resins. They withstand the most severely corrosive conditions at temperatures as high as 500°F (260°C). The membrane is hydrophobic and maintains its strength in both wet and dry environments. PTFE filter media provides durability for hostile acid aerosol monitoring. 1.0 µm pore size membrane.
PTFE-Coated Glass Fiber Filters are constructed from borosilicate microfibers and bonded with PTFE. The filters can be folded and handled without loss of fibers, and are specifically recommended for Method 26, PM10, and PM2.5 sampling. They are great for especially low loading rates and low absorption of acid gases such as SOx or NOx with at least 99.95% retention efficiency (0.3 μm DOP).
Glass Fiber Filters are most the commonly used filters for particulate sampling. All of the glass fiber filters are binder-free and exhibit at least 99.95% efficiency for 0.3 μm dioctyl phthalate (DOP) smoke particles. 934AH is available. These are not recommended for metals analysis.
Quartz Fiber Filters are manufactured from pure quartz without a binder and are ideal for ultra-low metal analyses, acidic gases, (except Hydrofluoric) aerosols, stacks and flue gas monitoring. Quartz fiber filters are pre-heated to reduce organic contaminates.
Acetate Filters are used in the Hexavalent Chromium SK-0061H system for filtering after sampling. They have a low static charge and high-strength composition. Acetate filters demonstrate good resistance to heat and low molecular weight alcohols.

In-Stack Thimble Filters

Apex Instruments stocks a variety of thimbles for in-stack particulate sampling. In-Stack Thimble Filters are seamless, high-purity filters, and they are available from a choice of two different types of fibers: borosilicate glass and quartz. The gas collection efficiency of the thimbles is 99.9% (0.3 micron DOP). The 25 x 90 mm thimbles are specifically manufactured for stack sampling and tapered for ease of loading. Cellulose thimbles are available upon request.