Filter nozzles are technical components installed in the nozzle plate of water treatment filters. Their function is twofold: during filtration, they retain the filter media (sand, activated carbon, ion exchange resins, anthracite) while allowing the treated fluid to pass through; during backwashing, they uniformly distribute the reverse flow to regenerate the filter bed. Without quality filter nozzles, filter media could escape from the filter and treatment efficiency could drop dramatically. Ilmap has been producing filter nozzles Made in Italy in thermoplastic materials and stainless steel for over 30 years, shipping to more than 100 countries.
The reference standard is DIN 19605, which recommends 60 filter nozzles per m² as the installation density on the nozzle plate. Nozzles must be evenly distributed across the plate to ensure balanced flow rates during both filtration and backwashing. In practice, the number may vary depending on the process type (pressure filtration or gravity filtration), the filter media used (silica sand, anthracite, granular activated carbon, ion exchange resins) and design flow rates. The optimal density is always defined by the process engineer responsible for the plant design.
Choosing the correct model and density of filter nozzles ensures uniform flow distribution across the entire filter cross-section. This eliminates preferential flow paths (channeling) and dead zones that compromise filtration quality. The practical outcome is threefold: higher purity of filtered water, reduced frequency and duration of backwash cycles, and extended operational life of the filter media. A properly designed filter with the right nozzles can reduce water and energy consumption during backwashing by up to 30 %.
Filter nozzles operate in two distinct phases. During the filtration phase, fluid flows downward through the filter bed and the nozzles — equipped with calibrated slots — allow the treated water to pass while preventing granular media from escaping. During the backwash phase, the flow is reversed: water and/or air are forced through the nozzles to expand and regenerate the filter bed, removing accumulated impurities. Slot size is critical: it is selected based on the type of filter media to prevent clogging or media loss.
Material choice depends on the plant's operating conditions. Polypropylene (PP) filter nozzles and their variants — PPFV and PVDF are the most widely used materials: cost-effective, lightweight, with excellent chemical resistance for most civil and industrial water treatment applications. Stainless steel filter nozzles (AISI 316, AISI 316L) and special alloys are required when high temperatures or aggressive chemicals are present, or when an operational life exceeding the standard is required. Ilmap is one of the few European manufacturers to offer the complete range in both material families.
There is no universally «best» filter nozzle model: the correct selection depends on three key variables — process conditions (temperature, pH, chemicals), filter media type (particle size, density) and the intended backwash method (water only, or water + air). Ilmap supports customers in technical selection through the online configurator and its technical support team. For a detailed assessment of your plant specifications, contact the Ilmap technical team directly. An error in nozzle selection compromises the entire filter efficiency and generates avoidable operating costs.
The difference between short-stem and long-stem filter nozzles is critical for correct backwash operation. Short-stem nozzles are used when backwash is carried out with water only: there is no need to create an air volume beneath the nozzle plate. Long-stem nozzles are mandatory when backwash uses water + air: the long stem ensures the formation of an air pillow beneath the plate, which is essential for uniform air distribution and to prevent the malfunction of the filter bed. Installing short-stem nozzles in a water + air system causes uneven distribution and inefficient backwashing.
Ilmap provides a complete system of accessories for filter nozzle installation. The main fixing solutions are: N fixing nuts (require access below the plate), TS expansion anchors, TL series nozzles and MP soft sleeves (top-down installation, no under-plate access required). For pipe mounting, specific accessories are available for horizontal and vertical manifolds. Ilmap is one of the few manufacturers to offer the complete range of G sleeves and accessories for concrete false floors, used in large gravity filters for municipal water treatment.
Yes, Ilmap filter nozzles are certified for contact with drinking water in accordance with the main Italian and European regulations. Ilmap product certifications obtained from accredited laboratories include: DM174 (Italian regulation), ACS (France), WRAS (United Kingdom), EU Regulation 10/2011 and EC 1935/2004 (materials in contact with food and drinking water). The certification refers to the finished product (the nozzle), not only the raw material: Ilmap has had its nozzles specifically tested because processing virgin polymer can modify its migration characteristics.
Yes. Ilmap offers an online configurator that allows you to enter your plant specifications (filter dimensions, media type, flow rates, operating conditions) and receive a personalised technical quote for filter nozzles. For complex installations or special requests, you can contact the Ilmap technical team directly via the contact form on ilmap.com.
Yes, Ilmap develops special filter nozzle solutions for non-standard applications: tailor-made stem configurations, threads and slot sizes, special materials and particular geometries for unconventional filters. The Ilmap «Specials» division handles these requests with short development times and dedicated engineering support, from technical drawing through to series production.
Ilmap produces millions of filter nozzles per year and maintains permanent stock of the most frequently ordered models, ensuring short delivery times for catalogue orders. For large quantities or special models, it is advisable to check availability with the Ilmap sales team. Ilmap serves customers in over 100 countries through a network of local distributors.
Yes, most Ilmap filter nozzles use standard threaded connections (WHITWORTH, GAS-BSP, METRIC, NPT), compatible with market nozzle standards and therefore with filters and nozzle plates from other manufacturers. To verify compatibility with existing installations or nozzles from other manufacturers, it is advisable to provide Ilmap with the existing plant specifications or a physical sample for a free technical verification.
Ilmap offers a complete range of filter nozzles divided into two main families. Thermoplastic nozzles (PP, PPFV, PVDF) include the P, T, R, D and D4 models, each designed for specific flow conditions and filter media types. Stainless steel and special alloy nozzles include the HTC and HT models, designed for high-temperature applications or chemically aggressive fluids. All models are available in short-stem and long-stem versions, and can be configured online via the Ilmap product configurator to receive a personalised quote.
Ilmap filter nozzles can be purchased directly via the quote configurator on ilmap.com, or through the network of authorised distributors present in Europe, the Middle East, Asia and the Americas. To find the nearest distributor or for direct orders, visit the Dealers section on the official website ilmap.com. All Ilmap filter nozzles are designed and manufactured in Italy.