Sand Media Filters

Sand media filters Working Principle

Sand media filter (also with name of FQG system) is a kind of high efficiency filter equipment in cutting down water turbidity, and purifying water. It uses silica sand asits filter medium. Under a certain pressure, the muddy water come through the granular or nongranular silica sand, which can efficiently hold back suspended solids, organisms, colloidal solids, micro-lives, chlorine, odour and heavy metal ions, etc.

It consists of several standard filter tank unit, with unique water distributor and water collector inside.automatic backwash valve can control all system’s backwash process.

Sand media filters Application

Sand media filters is mainly used in pretreatment in water turbidity removal, water softening, electrodialysis, electrodialysis reversal.
However, it makes function on surface water, under ground water as well. Sand media filters can also be widely used in fields of electronic power, petrochemical,metallurgy,electroplating, papermaking, textile, pharmacy, soft drinks, living water, industrial water, swimming pool, etc.

Sand media filters Features

Sand media filters can widely used at different application, such as water filtering, cooling water by-pass filtering, waster water treating, etc.

1. Sand media filters has flexible modules, which can combined under actual flow rate, on-site area.
It is operated backwash automatically, with time control, differential pressure control. Each filter element start backwash one by one, while no need stop operation in backwash.
2. With smooth water allocation. High efficiency in backwash, water saving, only 30% water consumption of traditional one. Filter uses ASM filter media, which is easy wash.
3. With unique 48” ball filtering unit, and light weight for the whole system. The normal concrete base can used to place. Easy install, no need any boom equipment.
4. With good anti-corrosion feature.
5. With lost cost, but long lifetime.
6. Water quality:
inlet water turbidity <80mg/L, outlet quality reach <20mg/L inlet water turbidity <20mg/L, outlet quality reach <5mg/L 7. Flow rate: it can treat 30-500m³/h

Sand media filters Internal Structure

Filter structure: main part includes filter tank, water distributor, water collector, hand hole and support base, etc.
Filter tank: it gives enough space for water distributor and collector. Each water collector has 55 water caps, which reforms a internal recycle flow when backwash, no sand leak.
Water distributor: it makes sure water flow smoothly on the padding sand media.
water collector: with 55 unique mushroom shape water caps makes sure water pressure in a balance. It can reforms a internal recycle flow when back wash, no sand leak.
Hand hole: There have a up and down hand holes, which is easy for installing and replacing water distributor and collector. Meanwhile, the upper hand hole, which is easy for inspecting and adding silica.And down hand hole, which is easy for clear and repair.
Support base: it is assemble, it can adjust in according to on-site situation.



Model Inlet diameter(mm) Outlet diameter(mm) Picture Material
PD-58P 100 100 2013927103813.jpg  Plastic

Sand media filters Silica sand

Silica sand: mined from silica bed. After milling, it becomes into irregular angular shape. When mixed with concrete, it has a good adhesion, which can increase slurry strength.
Sea silica: with smooth outside, and even grind and with salty.


Sand media filters Operation

Filtration Process

– The contaminated water enters the tank through the inlet manifold, transitioning to the 3-way valve and into the top inlet of each tank

– The two-stage deflector creates a uniform distribution for laminar flow across the media bed while avoiding channeling of the media bed

– Particulate is trapped and retained within the media bed resulting in clean process water flowing out through the stainless steel wedge wire underdrain, to the outlet of each filter tank and to the outlet manifold for end use


Backwash Process

– Backwash sequence is initiated by either elapsed time of the controller or pressure differential between the inlet and outlet manifolds

– Water or air pressure opens the 3-way valve causing the reverse flow of a portion of filtered water up through the stainless steel underdrain to hydraulically and uniformly lift the media bed

– The use of a hydraulically balanced underdrain in conjunction with a gravel pack creates a proper and uniform lift of the media bed while avoiding a turbulent backwash

– Entrapped particulates are released during the backwash event, exhausted through the backwash manifold and routed to a convenient location

– One tank at a time is backwashed while continuing to process water for use until the entire system is clean

– Once completed with the backwash, filtration continues until the next backwash event.


Sand media filters Control manner

Peide Backwash control valve is started by water pressure or an external power source.
Peide backwash control valve is composed of solenoid valve, hydraulic relay valve actuator or three-way valve.
Peide filter backwash control valve outlet normally open, drain valve normally closed.
Each outlet is sealed by its own independent sealing seat, but they are controlled by the same stem of seal diaphragm.
Valve is a complete, interactive set. When one outlet is turned on, the other outlet is in a closed state,
So backwash valve can be operated in two modes:

Sand media filters Model Specification

Technical and performance Parameters

Model FQG48-1 FQG48-2 FQG48-3 FQG48-4 FQG48-5 FQG48-6
Inlet & outlet Diameter(mm)


200 200 200 200




100 100 100 100


Flow rate(m3/h)


30-100 45-150




Maximum pressure(Mpa)


0.6(1.0) 0.6(1.0) 0.6(1.0) 0.6(1.0)


Filter area(m2)


2.26 3.39 4.52



Total length(mm)


2640 3960 5280 6600


Quartz sand(kg)


1720 2580 3440 4300


Drain valve interface(inch)


4”×3” 4”×3” 4”×3” 4”×3”


Filter medium and flow rate

Filtration precision Filter material(12-40cm) Recommend flow rate(m3/h) Backwash flow rate(m3/h)
General filter Quartz sand 1.0-2.0mm 40-50 35-55
Precious of quartz sand Quartz sand 
15-25 25-40

Other diameter silica sand can also be used, which reaches into function of filter precision and stain resistance.

Manufacturing material

Filter chamber Carbon steel(Epoxy asphalt coating paint)
Filter medium Delicate natural quartz sand
Water distributor Engineering plastics
Water collector Engineering plastics
Sealing ring Nitrile rubber

Sand media filters Installation

1. Check evenness of floor: it requires floor even, each meter evenness should less than 10mm, the concrete floor can bear 3 ton/m2.
2. Line tanks units in a queue in according to drawing.
3. Install drain valve.
4. Install general in/outlet pipeline. Notice to protect plastic drain valve from damaging.
5. Install differential pressure switch, in/outlet pressure gauge and vent valve.
6. Wire for the whole filter and pipelines.

Step1. Installation details


2.2way-3positon valve
3.six angle bolt
4.metal gasket
5.up and down hand hole
6.rubber gasket
7.filter tank legs
9.water distributor
10.water collector
11.rubber gasket
12.down hand hole cover
13.mental gasket
14.six angle bolt
15.inlet and outlet


1 Water distributor installation

16.O-ring N122*7
17.water distribution frame
18.water distribution plateHigh rate automated sand media filters for irrigation water
19.water distribution cover

1.Place water distribution palte (18) on plate, (17),tighten cover, and fix with o-ring(16).
2.Install water distributor from up hand hole. Insert water distribution frame into flange, tighten inlet screw cover, fix it at flange too.


2 Water collector installation

20.pressure cap
21.water cap
22.screw cap(23),connecting joint(24).water disperse

25.collector(26).O-ring N122*727.upper water collecting pipe
28.upper water collecting pipe cover
29.down water collecting pipe

1. Fix upper water collecting pipe cover (28) and three water caps (21) into pipelines (27), fix these three water capsat down water collecting pipe (29). Make sure each water collector needs 9 sets collecting upper and down pipelines.

2. Place two water allocate (24) at collecting tank (25). Fix a water cap at pressure cover (22), and tighten the pressure cover at collecting tank (25). Fix water allocating well, again fix a O-ring (26). Then place up and down , ecting pipes inside the tank from down hand, phole. Joint with flange at tank bottom, tighten with screw cap (9). Remember to inspect collecting tank move or not.

3. Joint each collecting pipe into holes. Two man install cooperate, insert a joint fitting (23) to fix all collecting pipes.

And unscrew water , screw cap (9), and fix with round flange.

3 Supper hand hole cap installation

Put o-ring into o-shape socket, cover with hand hole flange (4). Tighten with screw bolt (2) include gasket(3).

4 Support base installation

Supply support legs(3) and  support leg covers (10).

Step 2:QLQ system installation

QLQ shallow media filtering system    sand-media-filters-installation4
1. in/outlet DN200
2. filter tanks
3. cam lock joint fitting
4. vent valve 1″
5. in/outlet pressure gauge
6. inlet pressure gauge
7. inlet pipe DN200
8. three way drain valve 4″*3″
9. drain pipe DN100
10.differential pressure switch

Details installation process:

1.Range filter tank in order. Notice to ensure hand hole direction outside, so that easy for add sand and maintenance.
2.Install outlet pipe (1), adjust filter tank (2), to make sure outlet branch pipe and tank’s water collector at a same level. Weld cam locks (3), fix well.
3.Install three way drain valve (8), fix with cam locks.
4.Install inlet pipe (7), adjust inlet branch pipe, to make sure inlet branch pipe and three way drain valve’s inlet in a same level, welding with cam lock(3). Fix well.
5.Install drain pipe (9). Keep drain , branch, pipe and three way drain valve at a line, welding with cam lock. Fix well.
Install differential pressure switch (10), inlet and outlet water pressure gauge (5) and (6), vent valve (4).

Step 3:QLQ system pipeline and wire install
QLQ pipeline and wire drawing

1. Hydraulic pipeline connection

1.Each three matched with one solenoid. Current pipeline as a,b,c,d,e,f as shown.
2.Differential pressure (high pressure connection) match with inlet water pipe, low pressure connect with outlet pipe .
See dot line g1, g2 shown.

2. wire connecting

1. Each solenoid has two terminal connector. E.g: 1# solenoid fire wire connect at 1, null wire at N.
2. Differential pressure switch, power supply wire (AC220), earth wire connecting way please see check drawing.

Sand Media Filters pictures



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