Selection and Application of Industrial Pipeline Filters/Strainer
In industrial water treatment systems, from the pretreatment of raw water to process circulating water and then to wastewater discharge or reuse, various impurities such as suspended solids, particles, algae, and rust inevitably exist in pipelines. These impurities can significantly affect the operational efficiency and lifespan of downstream equipment (e.g., pumps, membranes, heat exchangers, and ion exchange resins). As the “gatekeeper” of the system, the proper selection and application of pipeline filters are crucial.
The primary function of a pipeline filter is to physically intercept and remove solid particles from the fluid by utilizing a filter screen or filter element of a certain precision, thereby:
To prevent impeller wear in pumps, heat exchanger tube blockage, malfunction of precision instruments, and scratching or fouling of reverse osmosis membrane elements.
Ensure that process water or discharge water meets specific cleanliness requirements.
Reduce equipment failures and downtime caused by impurities, lowering maintenance costs.
2、 Main types and characteristics
According to structure and function, industrial pipeline filters are mainly divided into the following categories:
Y-strainer
Simple structure, small volume, low resistance loss, and easy cleaning.
Widely used at the inlet end of pumps, instruments, valves and other equipment as coarse filtration protection. Usually used to remove impurities with larger particles.
Pay attention to the mesh size of the filter (usually 10-100 mesh), the material of the shell (cast steel, stainless steel, etc.), and the connection method (flange, thread).
basket filter
The filtration area is larger than that of a Y-shaped filter, with stronger pollutant holding capacity and more stable pressure drop.
Suitable for working conditions with slightly higher impurity content, such as circulating cooling water systems and source water pretreatment systems. Can be used as an upgraded alternative to Y-shaped filters.
In addition to the accuracy and material of the filter screen, the volume of the filter basket also needs to be considered to determine a reasonable cleaning cycle.
Automatic backwash filter
Equipped with automatic cleaning function, it drives the suction scanner or reverse water flow to clean the filter screen through pressure difference or time control, and discharges impurities from the system. Can achieve uninterrupted operation.
Suitable for continuous production, high impurity content, or situations where manual cleaning is inconvenient, such as large circulating water systems and precision filtration before membranes.
The core parameters include filtration accuracy, backwash water consumption, control mode (pressure difference/timing), and driving mode (electric/hydraulic).
Bag Filter
High filtration accuracy (up to 1 micron), easy replacement, one-time use, and no risk of cross contamination.
Suitable for high-purity water treatment, final filtration after chemical addition, or process points requiring low flow and high precision.
Select the number and size of filter bags based on flow rate and pollutant capacity, and choose filter bag materials (such as polypropylene, nylon, PTFE, etc.) based on filtration accuracy and corrosion resistance.
3、 Key factors for selection
Choosing the appropriate filter requires comprehensive consideration of the following factors:
The suspended solids concentration, particle size distribution, and impurity properties (viscosity, hardness, etc.) of the inlet water quality.
Filtering accuracy: determined according to the requirements of the protected equipment, commonly used units are “mesh” or “micrometer (μ m)”. The higher the precision, the better. Excessive precision will shorten the cleaning cycle and increase pressure loss.
The diameter of the filter must meet the system flow requirements, and the pressure rating of the housing and filter element must be higher than the maximum working pressure of the system.
The filter will generate pressure loss during operation, and it is necessary to ensure that its initial pressure drop and maximum pressure drop during the blockage process are within the allowable range of the system.
The material of the filter housing and filter element must be compatible with the temperature, pH value, and corrosiveness of the processing medium. Common materials include carbon steel, 304/316 stainless steel, PVC, etc.
Choose between manual cleaning or automatic cleaning based on site conditions. For manual models, consideration should be given to the convenience and frequency of disassembly and cleaning.
4、 Application suggestions
Graded filtration: For systems with complex impurities, a multi-stage filtration scheme of “coarse filtration+fine filtration” can be used to extend the service life of precision filters.
Reasonable installation: Filters are usually installed on the inlet side of the equipment. It is recommended to install a bypass pipeline next to the manually cleaned filter to ensure uninterrupted system operation during maintenance.
Regular maintenance: Establish strict maintenance procedures, regularly inspect and clean or replace filter elements. For automatic filters with differential pressure control, a reasonable differential pressure starting value should be set.
Summary
Although pipeline filters are small components, they are the “guardian angel” for the stable operation of industrial water treatment systems. Through scientific selection and rational application, not only can core assets be effectively protected, but the operational efficiency and economy of the entire system can also be significantly improved. It is an indispensable part of achieving intelligent and refined management of industrial water treatment.
