screen filter

Types of Screen Filters

Acreen filters come in numerous types, each with specific applications. Some of the common types include wedge wire screen filters, disc screen filters, and mesh screen filters.

• Wedge Wire Screen Filters: These screen filters are designed using V-shaped wires, known as profiles, that are spaced apart in a wedge shape. They form a cylindrical or flat filter element. The design allows for easy backflushing, a cleaning method in which the flow direction of the filtered liquid is reversed.
• Disc Screen Filters: The disc screen filter consists of a central manifold, several filter discs, and an end cap. The filter element, which is usually made of plastic homogeneous discs, provides a built-in filter separation of the individual components with a precise and even distribution of the flow. The function of the central manifold and end cap is to create a filter circuit.
• Mesh Screen Filters: These filters consist of a filter housing, strainer basket, and drain plug. The housing is usually made of aluminum die casting and contains an integrated metal strainer basket. When a liquid containing particles enters the strainer, the particles are trapped inside the strainer, while filtered oil can exit through the drain plug.

Maintenance and specifications of screen filters

Screen filters for water have different specifications based on their usage. The kind of water they filter also affects their specifications. Here are some general specifications:

• The main component of a screen filter is mesh, which is gauged in inches. The mesh size determines what particles the filter will catch. For example, a 1/8-inch mesh will let sand and silt through, while a 1/16-inch mesh will capture most silt and algae.
• Flow rate indicates how many gallons of water the filter will process in a minute. Flow rates range from 0.5 to 25 gallons per minute, depending on the screen mesh size and amount.
• Screen filters are manufactured in different pipe sizes from 1 inch to 6 inches. They are designed to fit common irrigation and plumbing pipe sizes.
• Durability is another important feature. Stainless steel and brass filters last longer than plastic ones. Stainless steel can last up to ten years, while plastic may degrade after three to five years.
• The micron rating of a screen filter indicates how fine the mesh is. The lower the micron rating, the more debris it will capture. Common micron ratings for screen filters are 50, 100, 200, and 400, but 100 mesh is usually preferred for irrigation systems.

Maintaining a screen filter is simple and only requires periodic flushing or cleaning. Flushing prevents clogging and maintains optimal water flow. Some filters are fitted with self-cleaning mechanisms that flush them at regular intervals.

• Switch off the pump supplying water to the filter.
• Open the drain at the bottom of the filter and flush out debris. It is helpful to note that opening the drain may cause water to flow in the opposite direction.
• Use a clean bucket to collect flushed debris. It is usually the sand or dirt that the filter has successfully captured.
• Repeat the flushing process six to eight times or until the out-flowing water is clean.

During cleaning, users can inspect the filter and flush out any debris. They can also use a soft brush to gently scrub the filter screen to remove any stuck particles. If cleaning a screen filter in a swimming pool, one can backwash the pool’s filter system to help clean the screen pool filter.

The maintenance requirement for a screen filter is generally low in comparison to other filter types.

Usage scenarios for screen filters

Usually, a screen filter has many applications in multiple industries and sectors. Some of these usage applications are as follows:

• Water treatment plants

  In water treatment plants, engineers use screen filters to separate and remove larger debris like leaves, twigs, and insects from the incoming raw water. This is usually the first step in the overall water treatment process. By doing this, the screen filter protects and makes the subsequent treatment units and chemicals more effective.

• Drinking water production

  In the process of producing drinking water, screen filters are useful during pre-filtration. The screen filters pre-filtration helps to remove larger particles. This prepares or subjects the remaining micro-filters and membranes to less load.

• Irrigation systems

  In irrigation systems, screen filters can help protect costly and delicate sprinkler heads and emitters. They achieve this by filtering out sediment and small particles from the water sourced from rivers, lakes, or wells.

• Industrial processing

  In industrial processing, screen filters are useful for protecting pumps, valves, and nozzles from becoming clogged by small settling solids. For example, oil-based screen filters can separate impurities and unwanted particles from oil before it is further refined and processed to become engine oil.

• Food and beverage industry

  In the food and beverage industry, screen filters have multiple applications. They are useful when producers need to remove pulp, seeds, and other solids from fruit juices and beverages during the process. Also, in the brewing industry, screen filters can separate solid residues from wort before fermentation takes place.

• Pharmaceutical production

  In the production of pharmaceutical products, screen filters help producers ensure product purity by removing contaminants and undissolved particles from solutions and liquids used in the pharmaceutical industry.

• Oil and gas industry

  In the oil and gas industry, screen filters find application by separating unwanted solids from crude oil and natural gas as they emerge from the wells. The filters serve to prevent the accumulation of debris in processing units and pipelines.

How to choose screen filters

When choosing industrial screen filters for purchasing, contemplating the production process, quality, capacity, and reputation of the supplier is essential. It's helpful to know if the suppliers offer custom filters and what kinds of screens their filters have. Are they woven, welded, twilled, or something else? Each type has its unique performance and application.

Are their screens made of stainless steel, brass, or another metal? Does the supplier offer different screen mesh sizes and filter shapes? Look at the catalog for what they supply. Can they make a filter with the exact dimensions you need for your industry? Find out if their screens are affected by HF, HHO, or high/low temperatures. Do they resist corrosion? Some materials withstand some chemicals and environmental conditions better than others. Also, consider their filters' flow rate and pressure drop properties. A screen filter with a higher flow rate and lower pressure drop can result in more energy savings and efficiency.

When using in a machine, do they have spare parts? Replacements are handy if the primary function gets broken. Their assemblies' compatibility with various pneumatic and hydraulic systems is another essential feature to check. You'll need screen filters that work with the equipment your industry has.

Find out the service life of the manufacturers' filters. A longer service life can lead to cost savings and reduced maintenance efforts. If the filters need to be changed often, it will be more expensive. Please look at the warranties that suppliers offer for their products. Is there an after-sales service to help you if the screens have any issues?

Finally, consider the suppliers' prices compared to their quality. Low-quality screens that break down fast will end up costing more, so be realistic about pricing. Check the reviews of their filters and see how many they export each year. Get references from previous buyers and contact them to learn about their experiences with the suppliers. Taking the time to do this will save you money in the long run and help your business succeed.

Screen Filter Q&A

Q1: What materials are used in industrial screen filters?

A1: Industrial screen filters can be made from many materials, such as stainless steel, nylon, and polypropylene. Steel offers great durability and heat resistance, making it suitable for various industrial applications. Steel can be used to make tubular, wedge, and woven mesh screen filters. Nylon offers a good level of chemical resistance and is suitable for low-temperature applications. It is mostly used to manufacture flat dual-layer screen filters. Dual-layer polypropylene screen filters combine viscoelastic characteristics with a good level of chemical resistance. They are suitable for the food and beverage industry.

Q2: How can users improve the performance of their screen filters?

A2: Users can improve the performance of their screen filters by choosing the right material for the filter. The selection will depend on the application. They can also determine the ideal mesh size and shape of the filter to achieve maximum flow while removing all contaminants. If possible, users can validate the filter before installation.

Q3: What are the recent trends in screen filter technology?

A3: There is a growing trend towards using durable filter materials offering better chemical resistance, such as stainless steel. Filters with automated backwashing capabilities are in high demand because they reduce labor costs and improve filtering efficiency. Another emerging trend is the customization of mesh sizes and filter shapes to meet specific industry requirements. This allows for improved filtration precision and functional performance.

Q4: What are the main downsides of industrial screen filters?

A4: The most common industrial screen filters have mesh openings between 0.1 and 1 mm. Such filters may not be able to trap very fine particles, resulting in a leak. Screen filters with large mesh openings may allow a large quantity of fluid to pass through, resulting in reduced productivity. Another downside is the limited surface area of cylindrical and conical screen filters. These types of filters may need to be replaced more frequently.

Q5: What are the right precautions when using industrial screen filters?

A5: To get the best performance from industrial screen filters, users should avoid over-pressurizing the filters. This can cause damage to the filter elements and leads to leaks. They should also avoid subjecting the filters to extreme temperature changes, which may cause thermal shock. Users should ensure that the filter is adequately lubricated before use to reduce wear and tear.