PP microfiltration machine

▍ Working principle

The working principle of a PP microfilter is based on sieving filtration and dynamic self-cleaning, and its operation is continuous and highly automated.

1. Filtration Process: The liquid to be treated enters the collection tank inside the microfilter through the inlet pipe or is directly sprayed onto the rotating drum filter screen. The core component of the equipment—a horizontally or slightly inclined cylindrical drum (whose outer wall is the PP filter screen)—rotates slowly under the drive of a motor. Under the influence of gravity, the liquid passes through the tiny pores of the PP filter screen, and the clean filtrate collects in the collection tank inside the drum and is discharged through the outlet pipe.

2. Impurity Retention: Suspended solids (SS) in the water with a particle size larger than the filter screen pore size are retained on the outer surface of the filter screen. As the drum continues to rotate, the retained impurities accumulate on the filter screen.

3. Backwashing (Self-Cleaning Process): When impurities accumulate to a certain level on the outer wall of the filter screen, potentially causing filter clogging and reduced filtration efficiency, the equipment's built-in level sensor or pressure sensor will send a signal (or according to a preset time interval) to initiate the self-cleaning program. 

● One or two rows of precision nozzles located above the rotating drum, driven by a high-pressure pump, spray extremely fine, high-pressure water jets.

● This high-pressure water jet precisely targets the filter screen surface, penetrating the screen wall in reverse to peel off and wash away impurities adhering to it.

● The washed-off impurities fall into a screw conveyor or slag collection trough below the equipment and are automatically collected and discharged.

4. Circulating Operation: The entire cleaning process takes only a few seconds. The drum rotates continuously during cleaning, ensuring almost uninterrupted filtration. This achieves continuous online operation and automatic cleaning, guaranteeing stable effluent quality and high production efficiency.

▍ Structural features

1. Core Filter Screen - PP Material:

● Material Advantages: The filter screen is made of food-grade polypropylene (PP) through injection molding or welding. This material has excellent chemical stability, is resistant to acid and alkali corrosion, and can handle various complex water qualities, avoiding the rust problems of metal filter screens.

● Molding Process: Manufactured using precision molds, the filter screen has uniform and precise pore sizes, and the filtration accuracy can be flexibly selected from 20 microns to 200 microns to meet different application needs.

● Surface Characteristics: The PP surface is smooth, does not easily adhere to contaminants, is easy to clean, and effectively reduces clogging.

2. Overall Frame and Components:

● Body Structure: Major structural components (such as the water tank, drum end cap, protective cover, etc.) also extensively use PP or reinforced PP material, achieving lightweight, corrosion-resistant, paint-free, and long-lasting performance.

● Drive System: Utilizes a cycloidal pinwheel reducer motor, providing smooth transmission, high torque, low energy consumption, and low noise, ensuring continuous and stable low-speed rotation of the drum.

● Flushing System: The core components are a stainless steel high-pressure pump and 316 stainless steel nozzles, providing a powerful and concentrated flushing water flow, resulting in high cleaning efficiency and low water consumption (typically less than 1% of the filtered water volume).

● Sludge Discharge Device: Standard configuration includes a screw conveyor (auger) to dry and concentrate the filter cake before discharge, significantly reducing the amount and cost of subsequent waste disposal. A scraper or direct discharge into a collection tank can also be selected depending on the situation.

● Control System: Equipped with an intelligent PLC control cabinet, it can automatically control the cleaning process in two modes based on liquid level difference and time settings, and also includes a manual mode for simple and intuitive operation. Fully automatic unattended operation is possible.

▍ Product Advantages

1. **Superior Corrosion Resistance:** Constructed entirely of PP material, eliminating concerns about corrosion from metal parts. This makes it particularly suitable for treating highly corrosive wastewater from seawater, chemical, electroplating, and papermaking industries.

2. **Low Operating Costs:**

● **Low Energy Consumption:** The main motor has low power consumption, and the intermittently operating flushing pump also has low power consumption, resulting in low overall power consumption.

● **Low Water Consumption:** The self-cleaning process is highly efficient, with minimal backwashing water consumption, saving water resources.

● **Low Maintenance Costs:** The simple structure and absence of easily damaged parts mean that PP components do not require regular anti-corrosion maintenance like metal components. Only simple daily inspections are needed, resulting in extremely low maintenance costs.

3. **High-Efficiency Continuous Operation:** Online automatic cleaning does not affect normal filtration. No downtime is required to replace filter media, ensuring continuous and stable production and significantly improving work efficiency.

4. **Excellent Filtration Effect:** The PP filter screen has uniform pore size, providing high and stable filtration accuracy, effectively guaranteeing the quality of the effluent.

5. **Environmentally Friendly and Convenient**:

● High concentration and small volume of discharged waste residue, reducing the cost and burden of sludge dewatering or off-site transportation.

● Lightweight equipment, easy installation, and low foundation requirements.

6. Long Service Life: PP material has good anti-aging properties; under normal use conditions, the main structure can last for more than 10 years.

▍ Scope of application

PP microfiltration units are widely used in various fields requiring continuous solid-liquid separation and filtration purification, primarily including:

● Aquaculture and Water Treatment: Pre-filtration in factory-scale aquaculture recirculating aquaculture systems to remove fish excrement, uneaten feed, and organic debris; raw water pretreatment to remove algae and plankton.

● Food and Beverage Industry: Pre-treatment of process water; recovery of useful substances (such as starch, protein, and fiber) from wastewater; solids removal from washing process wastewater.

● Paper Industry: White water recovery systems to filter and recover pulp fibers and purify circulating water.

● Chemical and Electroplating Industry: Treatment of wastewater containing chemical agents or metal hydroxides, including suspended solids separation and material recovery.

● Municipal and Domestic Wastewater: Used in wastewater pretreatment units, replacing traditional screens to remove fine suspended solids; deep pretreatment in greywater reuse systems.

● Other Fields: Pre-treatment and material recovery of mining wastewater, car wash wastewater, leather wastewater, textile wastewater, etc.

▍ Summarize

With its unique all-plastic corrosion-resistant material, efficient and automatic working principle, low operating cost, and wide applicability, the PP microfiltration machine has become an indispensable precision filtration equipment in modern industry and water treatment, providing users with an economical, reliable, and efficient solution.