LFQ Series Shallow Sand Filter | High Rate Sand Media Filter

Product Introduction

This LFQ shallow sand filter consists of one or multiple standard high-speed filter units, equipped with internal water distributors and water collectors. As a reliable filtration device matched with water filter housing; self-cleaning filter in the whole water treatment system, apart from quartz sand media, filter beds can also adopt activated carbon, anthracite and other materials to adsorb organic compounds and ions in raw water. The filter unit sizes cover from 16 inch (400 mm) up to 96 inch (2400 mm), with diversified installation options. It can run as an independent filtration system using existing water supply pumps, be installed as a side-stream filter with dedicated pumps, or connect multiple units on a shared pipeline for unlimited processing capacity expansion. Backwash modes include manual, semi-automatic and fully automatic. Users can activate backwashing via manual buttons, PLC, differential pressure signal or management system. The default backwash cycle lasts 3 minutes at factory setting. It can be controlled by a DCS automatic filtration system, or optional PLC control for centralized and remote communication requirements.

Working Principle

1. Filtration Mode

Pressurized raw water flows into the water distribution system at the top of the tank, spreading evenly across the filter media bed. Suspended particles are trapped inside the sand layer, and clean water is uniformly collected by the precision slit collector at the tank bottom and discharged out of the filter. As contaminants accumulate in the media bed, pressure loss gradually rises. Once the differential pressure hits the preset threshold or the scheduled cleaning time arrives, the system switches automatically to backwash mode.

2. Backwash Mode

Pressurized backwash water flows upward through the collector into the filter bed, fluidizing the sand media to strip off trapped sludge and pollutants, which are then drained out of the system. After a minimum 2-minute backwashing cycle, the valves reset automatically and the system returns to normal filtration operation.

Technical Parameters

Core Advantages

1. High filtration rate & low pressure loss: Solve the low flow rate and small throughput pain points of conventional media filters. 

2. Modular compact layout: Reduce land occupation by more than 40% and piping workload by over 50%, saving investment cost. 

3. Flexible backwash options: Manual, semi-auto and fully automatic backwash available to match different site requirements. 

4. Diversified backwash water source: Support internal system water, water tank water or external water supply with automatic switching. 

5. Wide size range: 16"–96" tank specifications, multiple units can be combined freely for any target flow rate. 

6. Premium core components: Imported control parts for stable long-term running. Single-gun filter design improves backwash effect and lowers sand leakage rate. 

7. Durable collector: Stainless steel or ABS material optional for extended service life. 

8. Bottom water storage design: Lower water resistance and easier maintenance access.

Application Scenarios

Industrial process water filtration: Heat exchanger and heat station water protection filtration

Industrial circulating water: Steel, metallurgy, paper making, power, petrochemical, food and HVAC systems

Raw water treatment: Surface water including river, lake and seawater pretreatment

Irrigation filtration: Farmland, park, municipal and golf course water treatment

Aquatic industry, swimming pool and water park water circulation purification

FAQ

Q1: What is the difference between shallow sand filter and conventional sand filter?

A: Shallow sand filter features much higher filtering speed, modular parallel design and smaller footprint. It is optimized for large flow circulating water side-stream filtration.

Q2: Can multiple LFQ filter tanks work together?

A: Yes. Tanks can be paralleled on shared piping. More tanks bring higher total treatment capacity.

Q3: Can we change filter media inside the tank?

A: Yes. Quartz sand, anthracite and activated carbon are all optional filter media to meet different removal targets.

Q4: Does it support automatic backwash by differential pressure?

A: Fully automatic version supports differential pressure trigger or timing trigger for backwashing.

Q5: Is it suitable for seawater filtration?

A: Yes, we can select anti-corrosion material for collectors and valves for seawater applications.

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