For a 20 m³/h well pump, a 2-inch hydrocyclone sand separator is usually the starting match, provided its rated flow window covers 20 m³/h with acceptable pressure loss. If the pump often runs above 20 m³/h, or water carries very high sand loads, compare a 2-inch and 3-inch unit before ordering.
What size sand separator is needed for 20 m3/h?
A centrifugal sand separator, also called a hydrocyclone, cyclone filter, or sand catcher, removes heavy solids by spinning water. Sand moves to the outer wall and drops into a collection chamber, while cleaner water exits the top.
Rule of thumb: select the separator by actual pump flow, not only pipe diameter. A 2-inch line commonly fits a 20 m³/h system, but the separator body must be rated for that flow at the available pressure. If the separator is too small, friction loss rises and separation can suffer. If it is oversized, water velocity may be too low to form a strong cyclone.
The HJLYGL model HJLX-3 hydrocyclone sand separator should be sized using the factory flow table for the selected inlet/outlet connection. For a pump nameplate showing 20 m³/h, ask for the pressure-drop curve at 20, 22, and 25 m³/h before finalizing DN50 or DN80.
How do flow, pressure, and particle load affect sizing?
Hydrocyclones need enough inlet velocity to create centrifugal force. They work better when the pump flow stays within the separator’s designed range and the feed pressure is stable. Low flow can reduce spinning force. High flow can increase head loss and push coarse particles through.
Use the pump’s real duty point—not the nominal motor size—to choose the cyclone. That duty point is flow at the well’s normal working pressure, including lift, pipe loss, filter loss, and irrigation equipment pressure.
- Normal sand load: a correctly rated 2-inch separator may be sufficient for 20 m³/h.
- Heavy sand or intermittent surges: a larger body can reduce pressure loss, but verify the minimum flow needed for cyclonic action.
- Frequent pump cycling: consider a larger settling or flush volume because sand can re-enter during startup.
- Variable-frequency drive: confirm performance at minimum and maximum speed, not only at 20 m³/h.
A sand separator does not replace fine filtration. It mainly catches coarse, high-density particles before water reaches screen filters, disc filters, or media filters.
Which separator connection and filter arrangement should follow it?
For a 20 m³/h irrigation line, DN50/2-inch connections are a common choice because they align with typical pump and header sizing. However, connection size alone is not enough. The internal hydrocyclone diameter and rated flow window determine performance.
Most well-water systems should use the hydrocyclone as the first-stage filter, followed by a screen strainer or disc filter. This sequence reduces abrasive wear and reduces clogging in emitters, drip tape, laterals, driplines, sprinklers, and micro-sprays.
| System point | Typical consideration at 20 m³/h | Practical note |
|---|---|---|
| Hydrocyclone inlet | Match separator body to actual flow and pressure | Start with 2-inch/DN50, then check the HJLX-3 flow data |
| Separator outlet | Keep short, straight connections where practical | Avoid reducers immediately before or after the unit when possible |
| Secondary filter | Screen filter, Y/T strainer, or manual disc filter | Use mesh or filtration degree suited to the emitter |
| Drip irrigation | Common disc grades are finer than basic strainers | HJLYGL disc elements range from 40 to 300 mesh, approximately 400 to 50 micron |
| Flushing point | Sand collection chamber or purge valve | Flush often enough to prevent re-entrainment |
For reference, HJLYGL manual T-type disc filter units include the 2-inch HJLYGLT002-1M2D and 3-inch HJLYGLT003-1M3D. Their published maximum flow range is 26–56 m³/h across the range, filtration area is 198–699 cm², and maximum working pressure is 10 bar. Exact model selection still depends on flow, dirt load, and required mesh.
How do you choose mesh or filtration degree after the cyclone?
The sand separator handles coarse grit, while the secondary filter protects small water passages. Mesh count, filtration degree, and fineness all describe the same general buying question: how small a particle the filter element is intended to stop.
Select the secondary filter from the emitter or nozzle requirement, then size the filter body for 20 m³/h with low head loss. A filter that is technically fine enough but too small will clog quickly and shorten flush intervals.
| Mesh | Approximate opening | Typical irrigation use |
|---|---|---|
| 40 mesh | Approximately 400 micron | Coarse protection after a cyclone; not usually enough for fine drip emitters |
| 80 mesh | Approximately 180 micron | Common for many field irrigation protections; HJLYGL green disc grade |
| 120 mesh | Approximately 125 micron | Finer protection for driplines and smaller passages; red disc grade |
| 150 mesh | Approximately 100 micron | Used where cleaner water is required; orange disc grade |
| 200 mesh | Approximately 75 micron | Fine filtration with more frequent cleaning in sandy water |
| 300 mesh | Approximately 50 micron | Very fine protection; needs adequate prefiltration and maintenance |
If the well produces noticeable sand, an 80 or 120 mesh secondary filter may be easier to operate than jumping directly to 150–300 mesh. Finer elements protect emitters, but they load faster when upstream cyclone performance is poor.
How do you install and size a complete well-water filtration unit?
A reliable installation treats the hydrocyclone, secondary strainer or disc filter, valves, pressure gauges, and flush line as one filtration unit. HJLYGL supplies irrigation filtration products from its Zhengzhou manufacturing operation and offers common port sizes from 1 to 4 inches with OEM/ODM options.
- Measure the pump’s actual flow at working pressure; do not assume 20 m³/h from horsepower alone.
- Request the HJLX-3 separator curve for 20 m³/h and nearby flows, including pressure loss.
- Choose 2-inch/DN50 if flow sits comfortably within the rated range; consider 3-inch/DN80 only if supported by flow and pressure data.
- Install the hydrocyclone before the screen or disc filter so heavy grit is removed first.
- Add pressure gauges before and after the complete filtration assembly to monitor clogging.
- Install a manual or automatic flush arrangement at the sand collection point.
- Select secondary mesh based on the smallest emitter, nozzle, or venturi injector passage.
- Check water after startup; excessive sand in the secondary filter means the cyclone size, flow, pressure, or flush cycle may need adjustment.
Plan for maintenance access during sizing. A separator that performs well but cannot be flushed or serviced easily will create downtime. Leave room to remove discs, screens, caps, and purge connections.
What is the practical specification for a 20 m3/h well?
A balanced package for many irrigation wells would start with a 2-inch hydrocyclone separator rated for 20 m³/h, followed by a 2-inch T-type screen or disc filter with adequate filtration area. If the well is sandy or the pump flow can exceed 20 m³/h, compare the pressure loss of a 2-inch assembly against a 3-inch option.
Do not choose solely by nominal pipe size; confirm the body rating, pressure loss, flush method, and secondary filter area. Typical lead time for common HJLYGL models is 7–15 days, sample orders are available, and warranty can extend up to 10 years under normal use, subject to the supply agreement.
Frequently Asked Questions
Is a 2-inch sand separator enough for 20 m3/h?
Often, yes, but only if that specific hydrocyclone body is rated for 20 m³/h at the available pressure. Check the flow curve instead of relying on connection size alone.
When should I choose a 3-inch separator instead?
Consider 3-inch/DN80 when pump flow runs above 20 m³/h, pressure loss through a 2-inch unit is too high, or the well carries a heavy sand load. Make sure the larger unit still receives enough flow to spin properly.
Can a hydrocyclone remove all sand from well water?
No. It is effective for heavier, coarser particles that respond to centrifugal separation. Fine silt and organic matter usually require a screen, disc, or media filter downstream.
What mesh filter should follow a sand separator?
Many irrigation systems start with 80 mesh, approximately 180 micron, or 120 mesh, approximately 125 micron. Use the emitter manufacturer’s requirement, and choose finer meshes only when prefiltration and cleaning frequency support them.
Does a higher mesh number mean finer filtration?
Yes. Higher mesh means more openings per inch and generally smaller openings. For example, 150 mesh is about 100 micron and is finer than 80 mesh at about 180 micron.
How much pressure drop is acceptable?
There is no single number that fits every system. The separator pressure loss must leave enough pressure for the downstream filter and irrigation equipment. Ask for the pressure-drop curve at the actual pump duty point.
Do I need both a centrifugal separator and a disc filter?
For sandy wells feeding drip tape or driplines, this two-stage arrangement is common. The cyclone removes coarse grit, while the disc filter catches finer particles that can plug emitters.
What information should I send to the supplier?
Send pump flow in m³/h, working pressure, pipe size, sand or silt condition, irrigation type, required emitter protection, water temperature, and whether flushing will be manual or automatic.
Size a separator around the pump’s true operating point, then protect it with a secondary filter selected for the smallest downstream water passage.