Custom Hydraulic Filter Element Specifications
A hydraulic filter element fails in one of two ways: it lets particles through, or it collapses. Both are specification problems, not manufacturing defects — and both are decidable before you send a drawing.
Tanqi builds made-to-specification hydraulic elements from multi-layer diffusion-bonded 316L sintered wire mesh, rated 1–200 µm. This guide sets out the four numbers that actually determine whether a replacement element behaves like the original: filtration rating per ISO 16889, collapse pressure per ISO 2941, seal compound, and end-cap geometry.
Filtration rating: ask for the beta ratio, not the micron number
“10 micron” on a hydraulic element is meaningless without a test method. A nominal rating may capture as little as 50% of particles at that size. The comparable figure is the beta ratio measured by the multi-pass method in ISO 16889, reported as βx(c) — the ratio of upstream to downstream particles larger than x microns, where “(c)” denotes calibration against ISO 11171 (counting by optical particle counter).
Industry practice for pressure-line elements is βx(c) ≥ 1000 at 2.5, 5, 7, 12 and 22 µm(c); some dirt-fuse designs are rated β = 1000 at 5 and 15 µm(c). A β of 1000 means 99.9% capture at the stated size. When you cross-reference a HYDAC, Pall or Parker part, match the beta curve — not the printed micron number — or you will silently downgrade the cleanliness class of the whole circuit.
| ISO 16889 rating | βx(c) = 1000 at | Typical circuit position | Notes |
|---|---|---|---|
| F03 (fine) | 4.5 µm(c) | Servo / proportional valve protection | Requires stable pore geometry under pressure spikes |
| F06 | 7 µm(c) | Pressure line, general hydraulics | Most common replacement target |
| F10 | 12 µm(c) | Return line, mobile equipment | Balances dirt holding against ΔP |
| F20 | 22 µm(c) | Suction / coarse pre-filtration | Protects pump inlet, low ΔP |
Collapse rating: the number that decides whether the element survives
ISO 2941 defines how collapse/burst pressure is verified. Standard pressure-line elements are commonly rated around 20 bar (290 psid) collapse, return-line elements around 10 bar (150 psid), while high-strength dirt-fuse designs reach 207 bar (3000 psid). Sintered wire mesh constructions typically give a collapse pressure 3–5× the rated operating differential — which is why they are specified where element failure would send debris into a pump, servo valve or turbine.
The practical consequence: a bypass-valve filter and a non-bypass filter of identical media can be rated 21 bar versus 210 bar. Specifying the wrong one is a common error when reverse-engineering from a part number rather than from the actual housing and duty.
Seal compound and end-cap geometry: where most leaks originate
Media specification is rarely the cause of a failed replacement. Connection geometry is. Bayonet interfaces (222, 226, 220 O-ring configurations), threaded connections in NPT / BSP / metric, and flanged or rod-mounted ends all have their own critical dimensions — and a 0.5 mm error in the seal land will leak regardless of how good the media is.
Seal compound must be matched to fluid and temperature. NBR covers −25 °C to +100 °C for mineral oil; FKM extends chemical and temperature compatibility; phosphate-ester and water-glycol fluids need their own elastomer selection. Confirm the compound against the actual fluid, not the oil originally specified at machine commissioning — fluids get changed.
- Provide fluid type, operating temperature range, and maximum working pressure
- State whether the housing has a bypass valve — it changes the required collapse rating
- Give ΔP at which the element is considered spent, and whether a differential indicator is fitted
- Confirm end-cap type with a dimensioned sketch or a photo of an existing element
Why sintered wire mesh for hydraulic duty
Multi-layer sintered wire mesh is diffusion-bonded in a vacuum furnace, so the pore geometry is fixed by metallurgical bonding rather than by mechanical compression. Glass-fibre and paper media rely on compressive forces to hold their structure; those forces relax at temperature and after pressure cycling, and the pores open up. A sintered 316L element rated 10 µm at ambient remains 10 µm at 120 °C and after repeated cleaning cycles.
It is also cleanable. Ultrasonic, chemical, backflush and steam regeneration all restore most of the original permeability, which is what makes a metal element economical in high-contamination circuits despite a higher unit price.
| Parameter | Range / option |
|---|---|
| Media | Multi-layer sintered wire mesh, diffusion bonded |
| Filtration rating | 1–200 µm |
| Materials | 304, 304L, 316, 316L, 310S, 317L, duplex |
| Max working pressure | Up to 32 MPa per design |
| Cleaning | Ultrasonic, chemical, backflush, steam |
| Lead time | 15–25 days FOB Tianjin |
Standards Referenced
Test methods and specifications referenced on this page are published by the following bodies. Confirm the current edition before specifying.
Frequently Asked Questions
Can you cross-reference a HYDAC or Pall part number directly?
We maintain a TQ cross-reference library covering HYDAC, Pall, Parker, CJC and Donaldson part numbers, but we do not release a TQ number from the part number alone. Dimensions are verified against your submitted drawing or a sample of the existing element — particularly the seal land, overall length and end-cap type — because the same part number has been produced with different end-cap geometries over its production life.