EPG-F
Garnet sits at SG 3.96–4.0, the heaviest of the common filter media. In the same vessel it lets you run a higher filtration rate, use a thinner bed, or hold more solids in the same volume.
| Grade | Sieve cut | Layer | Function |
|---|---|---|---|
| EPG-F-8 | 8/12# | Support layer (bottom) | Bottom support layer, retains the bed during backwash; high SG allows higher backwash rates without media loss |
| EPG-F-12 | 12/20# | Support / coarse layer | Pairs with 8/12 to form a graded support bed and limit inter-layer mixing |
| EPG-F-20 | 20/30# | Coarse filtration | Pre-filter layer for high-turbidity feed, extends fine-layer life |
| EPG-F-30 | 30/40# | Main filtration layer | Main bed in conventional multi-media filters — balanced dirt holding and pressure drop |
| EPG-F-40 | 40/60# | Main / transition layer | Transition layer for high-precision filtration, used ahead of the 140/200 fine layer |
| EPG-F-1 Same cut as EPG-Z-1 | 140/200# | Fine / polishing layer | Fine layer in multi-media filters; the same grade is also used for precision waterjet cutting of glass and thin plate (see TDS) |
Grey rows are grades in production whose parameters we have not measured for publication — request the batch TDS and you get measured values.
Filter media are accepted on specific gravity, effective size and uniformity coefficient — not on the soluble-salt or conductivity limits that apply to blasting. The same mineral is released to a wider conductivity at filter grade because it never contacts a prepared steel surface. Do not mix the two specifications.
Every figure on this page comes from the COA and TDS shipped with the goods. Grades that are not measured are listed by code only.
ENGINEERING NOTES
Anthracite around 1.4, silica sand around 2.65, garnet around 4.0. After backwash the bed re-stratifies by density with the heaviest at the bottom — no support grid needed to carry the load.
Heavier media needs a higher backwash velocity for the same bed expansion. Dropping garnet into a filter without changing backwash parameters is the most common field error.
Garnet runs below 2% free silica. Where silica sand is the medium, respirable crystalline silica is a real occupational-health item — particularly relevant for waterworks and food and beverage plants.
Mohs 7.5–8.0 means slow size decay under repeated backwash and a longer top-up interval than silica sand.
| Layer | Common media | Function |
|---|---|---|
| Top layer | Anthracite / activated carbon | Traps coarse solids and organics |
| Middle layer | Silica sand | Main filtration bed |
| Bottom layer | EPOWDER® garnet (this line) | Fine filtration; SG 4.0 holds the bed down |
| Support | Garnet coarse cut 8/12# | Stays in place through backwash |
ENGINEERING NOTES
| Parameter | Usual design value | Note |
|---|---|---|
| Effective size, ES (d10) | 0.25–0.35 mm | Corresponds to the 20/40 and 30/60 cuts in this line |
| Uniformity coefficient | ≤ 1.5 (AWWA B100 caps it at 1.7) | The higher the UC, the more the bed mixes on backwash |
| Garnet layer depth | 150–300 mm | Keep bed depth to ES above 1,000 |
| Filtration rate | 10–18 m/h; up to 25 on good raw water | Above 20 m/h, check for breakthrough |
| Backwash water rate | 35–45 m/h | Control to 10–15% bed expansion rather than a fixed rate |
| Air scour (if fitted) | 50–80 m³/(h·m²) | Air first, then water; this step carries the most mixing risk |
140–200#, the fine layer of a multi-media filter for tighter turbidity or suspended-solids targets. The same grade is also used for precision waterjet cutting of glass and thin plate, with full TDS data. Note its conductivity is on the high side at 250 μS/cm — specify a low-conductivity batch for low-salt duties.
Typical application: Fine layer in multi-media filters; the same grade is also used for precision waterjet cutting of glass and thin plate (see TDS)
| Garnet content | ≥95% |
|---|---|
| Free silica | < 2% |
| Total chlorides | ≤ 20 ppm |
| Conductivity | 250 μS/cm |
| Mohs hardness | 7.5–8.0 |
| Specific gravity | 3.96 |
| Bulk density | 1.96 g/cm³ |
| Radioactivity | 0.2 μSv/h |
| Mesh | μm | Cumulative passing |
|---|---|---|
| 80 | 180 | 0.00% |
| 120 | 125 | 5.50% |
| 140 | 106 | 36.00% |
| 200 | 75 | 90.70% |
| 230 | 63 | 96.90% |
| PAN | — | 100.00% |
These grades are in production, but we do not publish numbers we have not measured. Request the TDS and you get the real batch data.
The batch TDS and COA come back within 24–48 hours. Standard-grade samples ship in 3–5 working days; minimum one pallet.
Request TDS / quoteGarnet is the heaviest media in the vessel, so it does two jobs at once: it filters the finest fraction and it holds the bed down. Get the grading or the backwash wrong and the bed mixes within a few cycles.
Read the note →Material, machine, target result: three lines are enough. Grade recommendation within 48 hours; standard grades in stock, samples in 3–5 working days.
Get a grade recommendation peter@ef-global.cn