Introduction to Stainless Steel Filters

Stainless steel filters consist of a housing, multiple filter elements, a backwash mechanism, and a differential pressure controller. The internal diaphragm within the stainless steel filter housing divides the internal cavity into upper and lower chambers. The upper chamber contains multiple filter elements, maximizing filter space and significantly reducing the filter's size. The lower chamber houses the backwash suction cup. During operation, turbid liquid enters the filter's lower chamber through the inlet and then passes through the diaphragm holes into the inner cavity of the filter elements. Impurities larger than the filter element gaps are retained, while the clarified liquid passes through the gaps into the upper chamber and is finally discharged from the outlet.

I. Filter Machine

During operation, the water to be filtered enters through the inlet, flows through the filter screen, and exits into the required pipeline for process circulation. Particulate impurities in the water are retained within the filter screen. With continuous circulation, more and more particles are retained, slowing down the filtration speed. As wastewater continuously enters, the filter pores become smaller, creating a pressure difference between the inlet and outlet. When the pressure difference reaches the set value, the differential pressure transmitter sends an electrical signal to the controller, which activates the drive motor. The motor rotates the shaft via the transmission components, simultaneously opening the drain port to discharge the retained particles. Once the filter screen is cleaned, the pressure difference drops to the minimum value, and the system returns to its initial filtration state, resuming normal operation.

II. Working Principle

The filter element uses a high-strength wedge-shaped filter screen and is automatically cleaned via differential pressure control and timing control. When impurities accumulate on the filter element surface, causing the inlet/outlet pressure difference to increase to the set value, or when the timer reaches the preset time, the electric control box sends a signal to activate the backwash mechanism. When the backwash suction cup is aligned with the filter element inlet, the drain valve opens, and the system depressurizes and drains. A negative pressure zone, lower than the water pressure outside the filter element, is created between the suction cup and the inner side of the filter element. This forces some of the clean circulating water to flow from the outside to the inside of the filter element. Impurity particles adhering to the inner wall of the filter element are carried away with the water flow into the suction cup and discharged from the drain valve. The specially designed filter screen creates a jetting effect inside the filter element, flushing away any impurities from the smooth inner wall. When the inlet/outlet pressure difference of the filter returns to normal or the timer's set time ends, the material flow is continuous throughout the process. The backwashing water consumption is low, achieving continuous and automated production.

III. Design Features

1. The filtration equipment uses patented internal mechanical structures, achieving true high-pressure backwashing functionality. This easily and thoroughly removes impurities retained by the filter screen, ensuring thorough cleaning without dead zones, maintaining throughput and a long service life.

2. The stainless steel filter uses 304 and 316L stainless steel wedge-shaped filter screens, offering high strength, high precision, and corrosion resistance. The maximum filtration accuracy can reach 25 microns.

3. The stainless steel filter automatically backwashes through its self-checking and strain-relief functions, adapting to unstable water quality fluctuations without manual intervention.

4. The stainless steel filter has few wearing parts and no consumables, resulting in low operating and maintenance costs and simple operation and management.

5. The stainless steel filter operates precisely, allowing flexible adjustment of the backwash pressure difference and time settings according to different water sources and filtration accuracy.

6. During the backwashing process, each (group) of filter screens is backwashed sequentially, ensuring safe and efficient cleaning of the filter screens without affecting other screens, which continue filtering.

7. The stainless steel filter uses a pneumatic drain valve, resulting in short backwash duration and low water consumption, making it environmentally friendly and economical.

8. The stainless steel filter features a compact and reasonable structural design, requiring a small footprint and offering flexible installation and movement.

IV. Advantages of Stainless Steel Filters

1. Stable filtration effect;

2. Deep filtration, excellent dirt-holding capacity;

3. Simple operation and easy maintenance;

4. Low system operating costs, reliable performance, and a lifespan of over 10 years.

Stainless steel pleated filters use stainless steel material to prevent rust for a long time; main application industries include: chemical, power, steel, machinery manufacturing, food and beverage processing, plastics, papermaking, mining, metallurgy, textiles, petrochemicals, environmental protection, golf courses, automobiles, and pre-filtration for municipal water.

V. Technical Parameters

1. Filter screen pore size: 50-1000μm

2. Washing time: Approximately 23 seconds for a single backwash cycle

3. Inlet/outlet diameter:

In principle, the inlet/outlet diameter of the filter should not be smaller than the inlet diameter of the matching pump, generally consistent with the inlet pipe diameter.

4. Nominal pressure:

The pressure rating of the filter is determined according to the highest possible pressure in the filtration pipeline.

5. Mesh selection:

Primarily considers the particle size of the impurities to be intercepted, determined according to the requirements of the medium process.

6. Filter material:

Filter material is generally selected to be the same as the connected process pipeline material. For different service conditions, cast iron, carbon steel, low alloy steel, or stainless steel filter materials can be considered.

7. Filter Pressure Drop Calculation

For water filters, the pressure loss is 0.52～1.2kpa at the general rated flow rate.

VI. Installation and Use Precautions

1. This type of valve should generally be installed horizontally in the pipeline.

2. During installation and use, attention should be paid to the protection of the control box, sensors, and transmission parts to prevent damage.

3. Connect the pipeline according to the arrow direction indicated on the stainless steel self-cleaning filter body.

4. When debugging the electric part, please pay attention to the direction of rotation of the motor should be consistent with the marking direction.

5. During installation, it should be considered convenient for maintenance, and a bypass pipeline should be installed.

6. During installation, the drain port should be considered at the bottom as much as possible to facilitate the discharge of debris.

7. The drain pipe is connected to the drain ditch, and the drain pipe should not be too long.