Commercial Sand Filters

Side-mount commercial sand filters, 1200 to 2000 mm, up to 157 m3/h. Quick-closing manhole and 2.5 bar working pressure. Made in Egypt.

Side mount, and why commercial plant rooms need it

The commercial range puts the multiport valve on the side of the shell rather than on the lid. That leaves the top of the vessel clear for a manhole, so the bed can be inspected, topped up or changed without dismantling the valve and the pipework above it - which on a public pool is the difference between a morning''s work and a day''s closure.

Every vessel carries a quick-closing manhole: 300 x 400 mm on the WS-1200, and 400 x 500 mm on the WS-1400, WS-1600, WS-1800 and WS-2000.

The range, and flow at three design velocities

Commercial filters are specified at a chosen filtration rate, not at a single headline flow, because the rate is what the design standard fixes. The Waterstar range is published at 30, 40 and 50 m3/h per m2: WS-1200 passes 36, 45 and 56.5 m3/h; WS-1400 passes 46, 61.5 and 77 m3/h; WS-1600 passes 60, 80.5 and 100.5 m3/h; WS-1800 passes 76, 101.5 and 127 m3/h; and WS-2000 passes 94, 125.5 and 157 m3/h.

Public and hotel pools are normally designed at the lower end of that band. A filter selected at 30 m3/h/m2 carries roughly forty per cent less flow than the same vessel at 50, but it produces materially better water under bather load and it gives the operator headroom on a busy day rather than a filter already at its limit.

Pressure, temperature and connection

The vessels are rated at 2.5 bar working pressure and tested at 4 bar, with a maximum water temperature of 50 C. Flange and valve sizes rise with the vessel: 75-90 mm on the WS-1200, 90-110 mm on the WS-1400, 110-125 mm on the WS-1600, 110-140 mm on the WS-1800 and 125-160 mm on the WS-2000.

Confirm the flange size against the circulation pipework at design stage. On commercial plant the filter is frequently the item that sets the pipe diameter for the whole circuit, and a connection chosen late is an expensive correction.

The bed, and exactly what to order with the filter

Our filters are supplied empty. On a commercial vessel the media is a delivery in its own right — a WS-2000 takes nearly five tonnes — so it belongs on the order from the start, not discovered on site. The charge for each vessel is 0.4–0.8 mm silica sand over a 1–2 mm silica gravel underbed, at a minimum bed height of 1 m:

WS-1200 — 1375 kg sand (55 × 25 kg bags) on 300 kg gravel (12 bags). WS-1400 — 1650 kg sand (66 bags) on 450 kg gravel (18 bags). WS-1600 — 2150 kg sand (86 bags) on 675 kg gravel (27 bags). WS-1800 — 2800 kg sand (112 bags) on 750 kg gravel (30 bags). WS-2000 — 3800 kg sand (152 bags) on 1050 kg gravel (42 bags).

The gravel is a support layer, not a filtering layer. It keeps the sand off the collector laterals and spreads backwash flow evenly across the floor of the vessel, so the whole bed lifts rather than a channel opening through one part of it. All media to BS EN 12904.

Do not substitute a coarser sand for the 1–2 mm gravel — it is a different grade doing a different job. And do not under-charge to save a few bags: a short bed channels, and a filter that channels is passing unfiltered water at full flow while the gauge reads normal.

Sizing for commercial duty

Commercial sizing is driven by turnover and bather load together. Divide the pool volume by the design turnover - commonly four hours or less on a hotel, club or public pool, and shorter again on a children''s pool or high-load leisure water - to get the circulation flow, then select the vessel that carries that flow at your chosen filtration rate rather than at its maximum.

Send us the pool volume, the expected bather load, the turnover your authority requires and the plant room layout. Our engineers will confirm the filter diameter, the filtration rate it will actually run at, the pump duty and the pipe size as one set of numbers rather than as separate items.