Views: 209 Author: LOONG FILTRATION Publish Time: 2026-07-16 Origin: Site
The client is a well-known Turkish manufacturer of industrial fluid and food processing machinery, as well as an engineering service provider. In the dairy industry, maintaining consistent liquid quality while reducing capital expenditure (CAPEX) and operating costs (OPEX) is a primary goal. The client was seeking an efficient, automated engineering solution to optimize their dairy filtration line.
Milk is not a simple fluid; it is a complex, delicate colloidal emulsion containing water, milk fats, casein micelles, whey proteins, and minerals.
When utilizing traditional dead-end membrane or depth sheet filtration on cold raw milk:
The "Gel Layer" Effect: The fat globules and large-chain dairy proteins quickly accumulate on the membrane surface under pressure.
Instant Blinding: This accumulation forms a dense, impermeable "Gel Layer" (often referred to as membrane blinding ), completely blocking the pores almost instantly, halting production, and ruining the filter media.
Consequently, standard polymer membrane elements and depth sheet systems cannot be used to replace centrifugal separators. The only viable solution is a highly robust, cleanable stainless steel media integrated within an automated backwash candle filter system.
No. | Parameter | Specification / Process Detail |
1 | Process Flow Stage | Pre-pasteurization clarification (replacing the traditional clarifying separator). |
2 | Design Flow Rate | Continuous operating capacity of 20,000 – 30,000 L/h (upgraded from a standard 15 m³/h design ). |
3 | Daily Throughput | 40,000 to 50,000 liters per day. |
4 | Inlet Feed Temperature | 4℃ (cold storage milk directly entering the system). |
5 | Pre-Filtration Setup | Existing inline coarse strainer (Hat Filtresi) with a 2mm (2000μｍ) stainless steel mesh to block large particles like cow hair and grass straw. |
6 | Process Sequence | Originally: Raw Milk →2mm Coarse Filter→Separator (Temizleme Separatörü) →Pasteurizer (Pastörizatör). |
High Viscosity at Low Temperatures: Milk fat is highly viscous at cold storage temperatures (4℃). The replacement filtration system must handle this viscosity without experiencing high differential pressure .
Centrifugal Separator Replacement: A mechanical separator is highly efficient but comes with massive energy demands, complex maintenance, and high downtime. The replacement filter must match the separator’s efficiency in removing somatic cells and micro-impurities down to 20 microns without altering milk composition.
Hygiene and Sanitary Integrity: Every component must support CIP (Clean-In-Place) and prevent bacterial growth in the cold milk medium.
Challenge | Root Cause | Negative Impact |
High Capital & Maintenance Cost | High-speed rotating parts in traditional separators wear down rapidly. | Continuous spare parts expense and costly specialist maintenance. |
Massive Energy Consumption | Separators require heavy motor loads to drive centrifugal forces. | Increased factory utility bills and a larger carbon footprint. |
Production Interruptions | Frequent downtime required for manual cleaning of separator bowls. | Reduced daily plant throughput and process inefficiencies. |
Category | Requirement | Key Technical Need |
Performance | Reliable 20-micron filtration | SS316L sintered metal wire mesh to withstand cold milk viscosity without structural deformation. |
System Interface | High-flow pipe connections | Standard DN65 flange inlet/outlet connections to match the 20-30m³/h pipeline. |
Cleanability | Zero-downtime recovery | Automated liquid backwashing & nitrogen gas blowback sequences to clean the cartridges inline. |
Durability | Solid mechanical setup | Threaded cartridge interfaces to prevent bypass and eliminate structural failure under backpressure. |
To fulfill the client's goal of replacing the separator, LOONG Filtration engineered a customized Sanitary Stainless Steel Candle Backwash Filter System.
Material of Construction: Premium Grade SS316 housing.
Capacity: 30-round chamber designed to house 30" length cartridges.
Connections: DN65 Flange (Inlet/Outlet) to handle 20,000 - 30,000L/h flow smoothly.
Internal Design: Built-in heavy-duty threaded tubesheet plate to securely anchor each metal candle element.
Material: Sintered multi-layer Stainless Steel 316L.
Filtration Rating: 20 microns (μｍ).
Dimensions: 60 mm Outer Diameter, 30-inch length.
End-Style: Robust Male Threaded Interface for 100% bypass-free operation.
Sealing Gaskets: Food-grade Silicone O-rings, fully compliant with dairy regulations.
Successful Separator Replacement: The 20-micron sintered SS316L candle filter successfully replaced the heavy centrifugal separator, delivering pristine, clarified cold milk directly to the pasteurizer.
90% Energy Savings: Replacing the motorized centrifugal separator with static pressure-driven candle filtration dramatically cut down the processing line's electrical consumption.
Continuous Automated Operation: Rather than shutting down for manual bowl-cleaning, the system automatically runs the backwash cycle when the differential pressure reaches its limit, keeping the production line moving.
The candle filter system utilizes a 4-step cycle to manage continuous filtration, purging, liquid backwash, and dry-cake blowback.
Before starting filtration, close N2 port N4, N2 port N5, drain port N6, backwash port N7, and residue discharge port N8. Open inlet N1 and outlet N2.
The raw milk enters the candle filter from the material inlet N1 and passes from the outside to the inside of the 30-inch 20-micron SS Sintered Filter Cartridges. The clarified filtrate (clean milk) is discharged via the material outlet N2 directly to the secondary pasteurizer. Over time, microscopic dairy solids and somatic cells adhere to the outer surface of the metal cartridges, forming a thin filter cake.
Once a batch finishes or the system needs cleaning, the housing will still contain valuable unfiltered milk.
Close the material inlet N1, material outlet N2, N2 port N4, backwash port N7, and residue discharge port N8. Open N2 inlet N5 and drain port N6 (which is equipped with a dedicated 60mm diameter, 10" length, 20-micron auxiliary SS Filter Cartridge). Nitrogen gas is introduced through N2 inlet N5. Because nitrogen is less dense than the liquid, it rises to the top of the chamber, pressing down and forcing the remaining milk out through the drain-port cartridge to the secondary line until the filter housing is completely emptied, preventing any product waste.
With the liquid removed, only the dry solid residue remains on the outer cartridge walls.
Close the material inlet N1, material outlet N2, N2 inlets N4 and N5, and drain port N6. Open backwash port N7 and residue discharge port N8. Backwash solvent (ultrapure water at a pressure under 0.15MPa) enters through backwash port N7. The pressurized water flows from the inside to the outside of the SS sintered cartridges, knocking off the filter cake from the outer walls. The dislodged solids wash down the conical bottom of the vessel and exit via residue discharge port N8. This cycle typically runs for 10 to 15 minutes.
To clear any remaining stubborn residue or moisture from the filter mesh:
Close material inlet N1, material outlet N2, N2 inlet N5, drain port N6, and backwash port N7. Open N2 blowback port N4 and residue discharge port N8(). Compressed nitrogen gas (at a pressure not exceeding 0.1MPa) enters through N2 blowback port N4. The gas blows from the inside of the cartridges outward, purging any remaining particles on the outer mesh down to the conical discharge port N8. After a 5 to 10-minute gas purge, the candle filter interior is clean, dry, and ready for the next milk filtration cycle.
The "Gel Layer" Effect: Milk is a complex colloidal emulsion containing lipids (fat globules), proteins (casein and whey), and mineral salts.
Instant Blinding: If raw, cold milk is fed into a standard dead-end polymer membrane filter, the proteins and fats will rapidly adsorb onto the membrane surface under pressure. This forms a highly compact, impermeable "gel layer" that permanently blinds the membrane pores almost instantly.
The Solution: Only a robust, rigid metal media (such as our 316L sintered wire mesh) combined with dynamic, automated backwashing can handle this high-viscosity dairy stream without clogging.
Targeted Contaminant Removal: A traditional separator (Temizleme Separatörü) is primarily used to remove somatic cells, environmental dust, cow hair, and larger microbiological clusters from raw milk.
Precision Match: Our 20-micron absolute-rated sintered stainless steel mesh is perfectly sized to intercept these specific impurities.
Cost & Energy Efficiency: Unlike separators that rely on high-speed, energy-intensive rotating bowls, our candle filter operates statically under system line pressure. This drastically reduces power consumption, maintenance overhead, and capital investment while delivering equivalent milk clarity.
Nutritional Preservation: No. In homogenized or even raw milk, the average milk fat globule size is 3 - 4μｍ, and casein micelles are even smaller (0.02 - 0.2μｍ).
Zero Nutritional Loss: Since these essential nutrients are significantly smaller than the 20-micron pore rating of our sintered mesh, they pass through the filter completely unimpeded. The filter only targets unwanted somatic cells, environmental debris, and sediment, ensuring the milk's nutritional profile and taste remain fully intact.
Zero Product Waste: During Step 2 (Draining/Liquid Purging), nitrogen gas is used to empty the residual milk left inside the filter vessel at the end of a batch.
Secondary Security: To ensure that any loose solid residue inside the chamber does not escape into the clean milk line during this purging phase, the residual liquid is forced through this dedicated 60mm diameter, 10-inch, 10-micron (or 20-micron) auxiliary SS filter at the N6 port. This guarantees 100% of your milk is safely recovered and filtered.
Engineered for CIP/SIP: Absolutely. The entire filter housing is manufactured from sanitary SS316 with mirror-polished internal surfaces (Ra≤0.4μｍ) to eliminate dead corners.
Harsh Chemical Resistance: The 316L sintered metal wire mesh cartridges and silicone seals are fully compatible with standard dairy CIP chemicals (including hot 1.5 - 2％ caustic soda, nitric acid, and hot water flushes) as well as high-temperature steam sterilization.
LOONG Filtration is a trusted, certified manufacturer serving global dairy and industrial fluid markets.
Dual ISO Quality Certifications: Operating strictly under ISO 9001:2015 (Quality Management Systems) and ISO 13485 (Medical Devices Quality Management).
ASME & CE Compliant Sanitary Welding: Our candle filters are welded to the highest pressure vessel standards, ensuring no crevice corrosion, no microbial harboring zones, and absolute structural safety.
Custom Engineering Experience: Rather than offering off-the-shelf items, our engineers customize housing sizes, flow rates (from10 to 100TPH), and micron ratings to fit your unique dairy processing lines.
Optimize your dairy processing efficiency today.
Ready to transition from high-maintenance centrifugal separators to automated candle backwash filters? Contact a LOONG Filtration application specialist today for technical drawings and direct factory quotes.
