Mainline Compressed Air Filter CJ-050 C

1. Purpose and Operating Principle

The Grade C filter (polymer pre-filtration cartridge) is the first, coarsest stage of compressed air preparation in the CJ line. It reduces residual oil content in the stream to ≤3 ppm and prepares the air for further, finer filtration (stages T, A, X, H — see “Cartridge Compatibility” below). Grade C itself is not rated by the manufacturer for the micron size of particles retained — the technical documentation only states its residual oil figure and initial pressure drop. The 050 size is engineered for a significantly higher flow rate than the CJ-020 C/CJ-030 C and suits the mainlines of higher-output compressor stations.

2. Technical Specifications

3. Decoding the CJ-050 C Code

• CJ — mainline filter series (up to 1.6 MPa).
• 050 — body size (rated flow 5.7 m³/min).
• C — filtration grade (pre-filtration, polymer cartridge).

4. Design Features

1. Aluminum alloy body of high strength and hardness, with electrophoretic coating inside and out — corrosion resistance when operating with condensate.
2. Stainless steel cartridge frame with a diamond-pattern mesh — large airflow surface area and low resistance, important at this size’s higher flow rate.
3. Drain valve with O-ring seal — leak-tight condensate drainage without PTFE tape, fast and convenient installation.
4. Modular CJ series design — the filter belongs to a line of structurally compatible sizes (CJ-005…CJ-150, CJX-200…CJX-400), simplifying selection by flow rate and stepping up or down in body size as load changes.

5. Installation Recommendations

1. Mounting orientation. Install the filter vertically, with the condensate drain port facing down — for proper discharge of contaminants. At a body height of 563 mm, plan sufficient mounting clearance in advance.
2. Selection by flow rate. The rated flow of the CJ-050 C is 5.7 m³/min (201.3 CFM). At flows close to the maximum, account for the inlet-pressure correction factor (see the manufacturer’s “Pressure Correction Factor” table): below roughly 6–7 bar, actual throughput decreases.
3. Threaded connection. G 1-1/2″ thread — use the drain valve’s standard sealing elements; no additional PTFE tape is required.
4. Multi-stage filtration. For systems requiring higher air purity (painting, food production, precision pneumatic automation), install additional stages with FJ-050 T/A/X/H cartridges after the CJ-050 C, either in the same housing or in separate housings of the same size.

6. Cartridge Compatibility (within the FJ line)

The 050-size housing in the CJ series also accepts finer-grade cartridges from the same line:

• FJ-050 C — pre-filtration, residual oil ≤3 ppm (standard cartridge).
• FJ-050 T — fine coalescing filter, residual oil ≤1 ppm, particles ≤100,000/m³ in the 0.5–1 µm range.
• FJ-050 A — ultra-fine coalescing filter, residual oil ≤0.1 ppm.
• FJ-050 X — high-efficiency oil removal, ≤0.003 ppm, particles ≤10,000/m³ in the 0.5–1 µm range.
• FJ-050 H — activated carbon filter, ≤0.003 ppm, additional removal of oil vapor and odors.

ℹ️ The figures for the T/A/X/H cartridges are taken from the manufacturer’s general “Filtration accuracy of fj filter element” table (applicable to the whole CJ line) and do not refer to the CJ-050 C itself, which ships with a Grade C cartridge.

7. Common Mistakes

• Using the Grade C filter as the only filtration stage where residual oil content below 1 ppm is required — Grade C is designed only for coarse pre-filtration.
• Mounting in a non-vertical position — impairs condensate drainage through the drain valve.
• Using PTFE tape on the drain valve — not required and not provided for by the design; use the standard O-ring seal.
• Underestimating mounting space — at a body height of 563 mm, insufficient clearance below makes maintenance (unscrewing the bowl, replacing the cartridge) difficult.
• Ignoring the pressure correction factor — at reduced inlet pressure, the filter’s actual throughput drops (see the manufacturer’s table).

8. Applications

• Compressed air mainlines of high-flow production facilities — the first stage of air preparation.
• Air preparation ahead of fine/ultra-fine filtration — precedes installation of T, A, X, H cartridges in painting, food production, and precision pneumatic automation systems.
• Medium- and high-output compressor stations — protects pneumatic tools and actuators from large contaminants and excess oil.

9. Expert Opinion

Vitalii Boluchevski, lead engineer at Acvatron SRL (18 years of experience): “The CJ-050 C runs on the same proven pre-filtration principle as the smaller models in the line, but it’s sized for a significantly higher flow rate. At sites with several air consumers, the 030 size often turns out to be undersized for throughput — that’s when you need the 050 housing, otherwise the filter itself becomes the bottleneck of the line.”

10. FAQ

1. What filtration grade does the CJ-050 C have? Grade C — preliminary (coarse) filtration on a polymer cartridge, residual oil content ≤3 ppm.

2. Can the CJ-050 C be used as the only filter in a system? Yes, if air purity requirements are modest (e.g., general industrial pneumatic tools). For painting, food production, or precision pneumatic automation, an additional fine-filtration stage is needed after it (T/A/X/H cartridges).

3. What thread does the filter have? G 1-1/2″.

4. Is PTFE tape needed for installation? No — the drain valve is fitted with an O-ring seal, so no additional sealing is required.

5. What flow rate does the CJ-050 C handle, and how does it differ from the CJ-030 C? The CJ-050 C’s rated flow is 5.7 m³/min (201.3 CFM), versus 3.5 m³/min for the CJ-030 C, with the same G 1-1/2″ connection thread. The 050 model has a noticeably taller body (563 mm versus 345 mm), due to its larger filter element surface area.