Glass Fiber Folded PALL Replacement Filters for Steel & Power Plant Hydraulic Precision Filtration

1. Operating Conditions & Core Matching Logic

Hydraulic systems in steel mills (hot rolling mills, continuous casters, blast furnace auxiliaries) and thermal power plants 

(EH oil stations, turbine lubrication, boiler actuators) operate under continuous heavy loads. These environments demand

 high-performance replacement filter elements as critical spare parts to maintain oil cleanliness.

Key challenges include:

· Sustained oil temperatures of 90–120°C, with instantaneous peaks up to 130–150°C due to furnace radiation and load surges;

· Contaminants such as iron oxide abrasives, metal wear debris, varnish, oil sludge, sulfides, and rust particles;

· Frequent pressure fluctuations, cyclic flow impacts, and intermittent high-flow shocks that fatigue weak media;

· Strict cleanliness requirements for servo valves and precision actuators, typically ISO 4406 code 16/14/11 or better.

Standard single-layer paper or low-strength glass fiber media fail prematurely under these conditions—rapid DP rise, 

resin decomposition, fiber delamination, seal hardening, and unstable efficiency. Only upgraded multi-layer composite

 replacement elements can withstand high heat, abrasive pollutants, and hydraulic shocks to eliminate operational risks.

Our glass fiber pleated replacement filters are fully interchangeable with original Pall HC/UE series elements—same dimensions, 

interfaces, and internal valve parameters—enabling direct drop-in installation without housing modifications. They are 

engineered specifically for high-temperature, high-contamination, vibration-prone steel and power plant applications, 

delivering four core benefits: stable precision filtration, high dirt-holding capacity, thermal-fatigue resistance, 

and broad fluid compatibility (mineral oils, phosphate esters, water-glycol).

2. Graded Technical Specifications – Multi-Layer Glass Fiber Media

All media comply with ISO 16889 (multi-pass) and ISO 3724 (flow fatigue) standards. The gradient asymmetric pore structure 

traps contaminants stepwise: coarse outer layers capture large debris, middle layers adsorb sludge and colloids, and dense

 inner layers retain fine abrasive particles—preventing rapid surface blinding.

Grade Media Type Continuous Temp. Range Peak Tolerance Beta Ratio (βₓ≥200) Dirt Holding Capacity Typical Applications

Grade 1 Standard medium-temp glass fiber –10°C to +100°C 110°C (short) 1/3/5/7/10 µm 1,300–1,500 g/m² Cold rolling auxiliaries,

 low-load power plant lube stations

Grade 2 Reinforced high-temp glass fiber –10°C to +120°C 130°C (≤30 min) 1/3/5/7/10 µm 1,800–2,200 g/m² Hot rolling lines, 

conventional EH oil stations (mainstream choice)

Grade 3 Ultra-high-temp customized glass fiber –10°C to +140°C 150°C (≤20 min) 1/3/5/7/10 µm 2,300–2,700 g/m² Furnace-front

 heavy-load stations, boiler actuators (extreme heat)

Key aging benchmarks:

· Grade 1: 500h at 100°C → tensile strength retention ≥83%, efficiency loss ≤3%.

· Grade 2: 1000h cyclic 110°C + 130°C thermal shock → tensile strength ≥91%, efficiency loss ≤1.8%.

· Grade 3: 1200h at 140°C with sulfide-laden oil → strength retention ≥96%, no embrittlement.

Replacement threshold: Replace immediately when tensile strength retention drops below 75%, beta value衰减 exceeds 10% 

in one service cycle, or initial DP rises >120 Pa above factory baseline—indicating resin softening and permanent flow restriction.

3. Matched High-Temperature Structural Components (100% Interchangeable with Pall Originals)

Component Grade 1 (≤100°C) Grade 2 (≤120°C) Grade 3 (≤140°C)

Seals NBR (–40 to +100°C) Standard FKM (–20 to +120°C) Modified full-fluorine FKM (–20 to +140°C)

End-cap adhesive Polyurethane (≤110°C) Fluorine-containing epoxy (≤145°C) High-temp epoxy (≤160°C)

Bypass valve gasket NBR (stable to 100°C) FKM (stable to 130°C) Full-fluorine FKM (stable to 150°C)

Support skeleton Galvanized carbon steel 304 stainless steel 316L stainless steel (anti-corrosion)

All bypass valves are calibrated to 3 bar ±10%, matching original Pall settings. Stainless steel skeletons (wall thickness ≥1.2 mm) prevent collapse under high differential pressure and resist rust formation in humid pump-room environments.

4. Application-Specific Selection Guide

Working Condition Recommended Grade Operational Restrictions

Cold rolling auxiliary, oil ≤100°C, peak ≤105°C Grade 1 + NBR seals Install heat shields; drain water from tanks regularly.

Hot rolling roughing/finishing, EH oil, 100–120°C, peak 125–130°C Grade 2 + FKM seals (covers 90% of steel & power applications)

 Optimize cooling flow; record DP per shift; avoid >120°C for >4h continuously.

Furnace-front / boiler actuator, 120–140°C, frequent 140–150°C spikes Grade 3 + full-fluorine FKM + 316L skeleton Add auxiliary

 coolers to keep avg. <130°C; shorten replacement interval by 30%.

Flow velocity limits (to prevent media fatigue):

· Grade 1: ≤0.8 m/min (20% margin)

· Grade 2: ≤0.7 m/min (25% margin)

· Grade 3: ≤0.6 m/min (30% margin)

For systems with online backwash, ensure compressed air dew point ≤ –20°C and residual oil ≤0.1 ppm. Backwash pressure

 should be 0.4–0.5 MPa to avoid pleat collapse.

5. Common Failure Modes & Corrective Actions

Fault Root Cause Solution

End-cap leakage, seal hardening NBR seals used above 100°C; radiant heat without insulation Upgrade to FKM-sealed elements; 

wrap housing with 20mm insulation cotton.

Rapid DP rise, servo valve scratching Low-temp media used at 120°C; resin decomposed; cooling failed Upgrade to Grade 2 media;

 overhaul cooling system to stabilize <120°C.

Bypass valve fails to open (pump vibration) NBR valve gasket softened at high temp; sludge stuck on spool Replace with full FKM 

valve assembly; shorten backwash intervals.

Rust debris causing secondary contamination Galvanized skeleton in high-humidity pump room Switch to 304/316L stainless 

steel skeleton; drain tank water regularly.

Daily maintenance checklist:

· Weekly: Inspect heat insulation integrity on filter housings.

· Per shift: Record DP readings for high-temperature stations.

· Prohibited: Air-blasting disassembled elements (scratches resin layer); water/solvent cleaning (corrodes FKM and adhesive); 

mixing seals of different temperature grades.

Frequently Asked Questions (FAQ)

Q1: Are your replacement filters truly interchangeable with original Pall HC/UE series elements?

A: Yes. We manufacture to original Pall drawings—same outer diameter, inner bore, height, thread, seal groove profiles, 

and bypass valve settings. Installation requires no housing modifications, adapters, or shims. Every batch is verified with

 CMM inspections.

Q2: What micron ratings do you offer for steel and power plant applications?

A: We offer absolute ratings of 1, 3, 5, 7, 10, 20, and 25 µm—all with Beta ratio βₓ ≥ 200 (ISO 16889). For servo-valve protection, 

we recommend 3–5 µm; for general lube circuits, 10–20 µm. Custom ratings are available upon request.

Q3: Can you supply test certificates for export and customs clearance?

A: Absolutely. Every shipment includes EN 10204 Type 2.1 material certificates, ISO 16889 multi-pass performance test reports, 

and factory inspection records. Upon request, we can provide Type 3.1 third-party inspection or Lloyd's/ABS surveyor reports

 (additional cost applies), meeting EU, ASEAN, Middle Eastern, and South American import requirements.

Q4: Do you keep high-temperature Grade 2 and Grade 3 elements in stock?

A: Yes. Grade 2 (120°C) elements are always in stock for rapid dispatch. Grade 3 (140°C) custom elements require 7–10 working 

days for production. Trial orders (1–10 pcs) ship within 3–5 days; bulk orders (500+ pcs) within 15 working days. Emergency

 airfreight is available.

Q5: How often should I replace the filter element?

A: We recommend replacement when differential pressure reaches 1.0 MPa (10 bar) or every 6–12 months, whichever comes first. 

However, in high-temperature steel/power applications, we advise monitoring DP per shift and replacing immediately when

 the DP rise rate doubles compared to baseline—indicating accelerated media aging.

Q6: Do you offer elements compatible with phosphate ester or water-glycol fluids?

A: Yes. For phosphate esters (EH fluids), we supply FKM or EPDM seals and specially treated media. For water-glycol (HFC), 

we recommend stainless-steel mesh elements or chemical-resistant glass fiber. Please specify your fluid type when ordering.

Q7: Can you produce custom elements for non-Pall housings (e.g., Hydac, Parker, Mahle, Donaldson)?

A: Yes. We routinely manufacture replacements for Hydac, Parker (Racor), Mahle, Donaldson, MP Filtri, and many other brands. 

Send us your original sample or drawing, and we will reverse-engineer a 1:1 match with equivalent or better performance.

Q8: What is the lead time for custom-labeled elements with my brand?

A: For private-label orders (custom packaging, laser etching, or color-coded end caps), MOQ is 50 pcs per model. Lead time is 

15–20 working days after sample approval. We also offer co-branding for EPC contractors and distributors.

Q9: Do you provide technical support for installation or troubleshooting?

A: Yes. Our in-house engineers have 15+ years of hydraulic filtration experience. We offer free dimensional drawings,

 installation guides, and remote video troubleshooting. For large-scale projects, on-site commissioning support can be arranged.

Q10: How do I select the correct temperature grade for my application?

A: Measure the continuous oil temperature at the filter housing inlet over a full production shift. Add 10°C safety margin for

 transient peaks. If continuous temp is ≤100°C → Grade 1; 100–120°C → Grade 2 (most common); 120–140°C → Grade 3.

 For borderline cases, we recommend Grade 2 with enhanced cooling or Grade 3 for longer service life.