Decanter Centrifuge Failure Causes and Diagnostics

Brief Working Principle

A decanter centrifuge separates phases by using high centrifugal force to stratify materials with different specific gravities. The heavy (solid) phase is conveyed by a rotating screw conveyor toward the conical end and discharged, while the light phase overflows through the liquid outlet. This allows continuous, automatic solid–liquid separation.

Typical Causes of Vibration, Instability and Failure During Feeding

1、Bowl speed too high during feed start-up
If the bowl speed is excessive while introducing feed to decanter centrifuge, the slurry can be unevenly dispersed across the bowl. That uneven mass distribution produces unbalanced centrifugal forces and causes vibration. Consequence: increased bearing loads, accelerated wear, and potential mechanical damage.

2、Uneven or changing feed concentration
Fluctuations in feed solids concentration or non-homogeneous feed lead to uneven distribution of the mother liquor in the bowl. This produces oscillation and unstable operation. Consequence: repeated transient imbalances that may worsen over time and damage the equipment.

3、Rigid or insufficiently isolated foundation
A rigid mounting or poor vibration isolation transmits imbalance to the entire structure and amplifies vibration. Consequence: stronger oscillation, higher loads, and reduced centrifuge lifespan.

4、Electrical and control faults
Damaged power switches, wiring issues, incorrect supply voltage, or blown fuses disrupt motor control and may cause failed starts or abrupt shutdowns. Consequence: unreliable operation and possible electrical damage.

5、Auxiliary system failures (air pressure, filter cloth, actuators)
Low air-compressor pressure, faulty pressure switches, or closed or blocked pneumatic valves prevent pneumatic components from operating normally. Loose or slipping filter-cloth tension mechanisms cause tracking issues. Consequence: operational alarms, improper dewatering, and mechanical stress.

6、Ignored alarms or interlock responses
Alarms often indicate abnormal conditions. Ignoring them may cause small issues to escalate into major problems. Consequence: severe equipment damage or unexpected downtime.

7、Mechanical wear or protection failures
Worn bearings, damaged seals, degraded wear parts, or faulty protection devices (vibration sensors, torque limiters) increase vibration risk. Consequence: higher failure risk and increased repair frequency.

Recommended Diagnostic Checklist

1、Visual and mechanical checks: Verify bowl and scroll speeds, ensure slow-speed feeding, check feed homogeneity, and inspect foundation isolation.

2、Monitor operating parameters: Check vibration, temperature, torque, and motor current.

3、Electrical and control checks: Inspect power switches, fuses, wiring, panel settings, and interlocks.

4、Auxiliary system checks: Confirm air pressure, valve function, filter cloth tension, and pneumatic components.

5、Component inspection: Evaluate bearings, seals, wear liners, and the base.

Corrective Actions and Preventive Measures

Operational controls: ramp up bowl speed slowly during start-up, use consistent feed concentration, and avoid air entrainment.

Foundation: ensure proper vibration isolation and tighten anchor bolts.

Instrumentation: maintain vibration and temperature monitoring with automatic shutdown limits.

Maintenance: perform scheduled inspection and replacement of bearings, seals, and wear parts.

Training: ensure operators follow correct start-up, shutdown, and alarm-handling procedures.

Summary

Most failures and vibrations during operation originate from imbalance caused by excessive bowl speed, unstable feed, poor foundations, electrical faults, or auxiliary system issues. Proper operation, stable feed conditions, monitoring, and preventive maintenance can significantly reduce failure risk and ensure long-term stable performance of the decanter centrifuge.

GNLW454GT Mud Dewatering Centrifuge for  Hydrovac Slurry Treatment

GN Separation is proud to introduce the GNLW454GT Mud Dewatering decanter centrifuge, an advanced and robust solution engineered for the efficient treatment of hydrovac slurry and directional drilling mud. Designed to meet the growing demands of utility construction, trenchless drilling, and hydroexcavation projects, this high-performance decanter centrifuge plays a central role in modern waste management systems where reliable solids–liquid separation is essential. Continue reading →

GNLW224 Dewatering Centrifuges Ready for Overseas Client FAT

GN Separation is proud to announce that a new set of GNLW224 dewatering centrifuges, together with an integrated, intelligent polymer dosing system, is now fully assembled and ready for Factory Acceptance Test (FAT) for our overseas client. This package represents GN’s continuous commitment to providing high-efficiency, automated, and user-friendly dewatering solutions for global environmental and industrial applications.

Fig. 1   Horizontal decanter centrifuge

Smart Polymer Dosing System — Enhancing Dewatering Efficiency

In any sludge dewatering process, the polymer dosing system plays a decisive role. Proper flocculant preparation and accurate dosing directly influence the formation of strong, stable flocs, which ultimately determine the separation performance of a decanter centrifuge. For this project, GN has supplied a fully automated, three-tank polymer preparation unit, equipped with precise dosage control and real-time adjustment features.

The intelligent dosing system works seamlessly with the GNLW224 centrifuge. By monitoring feed flow, sludge characteristics, and centrifuge load, the control logic automatically adjusts polymer concentration and dosing rate. This ensures optimal floc formation under varying operational conditions, helping the centrifuge achieve higher dryness, cleaner centrate, and lower polymer consumption. For end users, this means lower operational costs and more stable long-term results.

Fig. 2 Polymer dosing unit.

GNLW224 — Compact but Powerful Dewatering Centrifuge

The GNLW224 model is GN’s compact-size dewatering centrifuge widely used for municipal sludge, industrial wastewater, and small-scale treatment systems.

When paired with the intelligent dosing unit, the GNLW224 becomes a complete, plug-and-play dewatering package suitable for overseas installations where local commissioning resources may be limited.

Smooth Integration and Easy Operation

The entire system—including the centrifuge, dosing unit, pumps, and control cabinet—is pre-installed, wired, and tested on the skid before FAT. GN engineers simulate on-site working conditions to verify mechanical operation, control logic, safety interlocks, and communication between the dosing system and centrifuge. This integrated design allows the end user to achieve quick installation, fast startup, and minimal operational tuning.

Ready for FAT and Global Delivery

With all mechanical and electrical checks completed, the equipment is now ready for the final FAT procedure with our overseas client. After FAT approval, the system will be packed and shipped, continuing GN’s mission of delivering reliable separation technology to partners worldwide.

GN Separation will keep advancing intelligent control, automation, and environmental technologies to support global customers with efficient and dependable dewatering solutions.

 

 

Introduction of the main characteristics of a decanter centrifuge

The decanter centrifuge is one of the separation machines. Compared with other centrifuges, it has its special features, and these special features also enable the centrifuge to better improve the efficiency of the work, so it It can bring convenience to the entire project process.

Regarding its special features, there are mainly the following points:

1. The work of the decanter centrifuge is mainly relying on centrifugal force, which drives the entire centrifuge to perform high-speed work, so that it can exert its effects. It has a relatively strong effect on the dehydration of solids. During the entire dehydration process, manual operations are not required, and fully automated operations can be realized only by controlling it to a certain extent.

  1. When we are using the decanter centrifuge, it is very necessary to protect and maintain it. The maintenance requirements of the decanter centrifuge are relatively ordinary. Only simple care is required at ordinary times. It requires frequent and complicated maintenance.
  2. The decanter centrifugelooks like a compact machine in appearance, it occupies a relatively small space, and the entire distribution equipment is relatively simple. During the use of the decanter centrifuge, as long as it is routinely protected and maintained, its service life will be very long.

GN high-end CNC lathes, CNC centers, and CNC gantry milling machines can better ensure the machining accuracy of centrifuge parts. In terms of the dynamic balance of the decanter centrifuge, in addition to the ordinary low and medium speed dynamic balance, GN also applies a high speed dynamic balance process, which can dynamically balance the centrifuge screw and bowl at the actual working speed of the centrifuge. In terms of market applications, GN decanter centrifuges are widely used in the industry, and the products are exported to more than 60 countries and regions in the world, and have won high praise from customers.

Decanter Centrifuges: Trends, Applications, and Safety in Modern Industry

Decanter centrifuges have become a cornerstone in industrial separation processes, offering reliable performance across wastewater treatment, chemical processing, food production, and the oil & gas sector. Their ability to efficiently separate solids from liquids makes them indispensable for operations seeking higher productivity and lower operational costs.

Fig.1 Decanter Centrifuge

The trend in centrifuge technology is moving towards greater automation and control. Modern decanter centrifuges increasingly integrate PLC (Programmable Logic Controller) systems, enabling precise control over rotational speed, feed rate, and cake dryness. PLCs not only optimize separation efficiency but also enhance safety by allowing real-time monitoring and automated fault response, reducing human intervention and operational risk.

In oil and gas applications, safety is paramount. Explosion-proof (Ex) designs for motors, electrical cabinets, and control panels ensure that centrifuges can operate safely in potentially hazardous environments. The combination of robust mechanical design, PLC automation, and explosion-proof technology makes centrifuges a reliable choice for demanding industrial settings, including offshore drilling, refinery wastewater treatment, and drilling mud processing.

At GN Separation, we have delivered solutions worldwide—from pharmaceutical wastewater treatment plants in Europe to power generation facilities in Asia—demonstrating the versatility of decanter centrifuges. As industries demand higher efficiency, safer operation, and remote monitoring, the adoption of PLC-controlled, explosion-proof centrifuges continues to grow, solidifying their role as essential equipment in modern process engineering.

GNLW364-VFD Dewatering Centrifuge for Overseas Pharmaceutical Plant Wastewater Treatment

In the pharmaceutical manufacturing industry, wastewater treatment is one of the most critical yet challenging processes. Pharmaceutical effluents often contain high levels of suspended solids, organic matter, and other complex compounds that must be efficiently separated before discharge or reuse. The GNLW364-VFD dewatering centrifuge is designed to address these challenges, providing a reliable and energy-efficient solution for solid-liquid separation in pharmaceutical wastewater treatment systems.

1. Meeting the High Standards of the Pharmaceutical Industry

Pharmaceutical production demands strict compliance with environmental and regulatory standards. The GNLW364-VFD centrifuge ensures effective dewatering of sludge while maintaining process cleanliness and safety. Constructed with stainless steel 316L contact parts, the unit offers superior corrosion resistance against chemical agents commonly present in pharmaceutical waste streams. Its fully enclosed design minimizes odor emission and contamination, creating a clean and hygienic working environment.

2. Optimized Performance with Variable Frequency Drive (VFD)

Equipped with a VFD control system, the GNLW364 allows operators to precisely adjust the bowl and scroll speeds to suit different feed conditions. This flexibility enables optimal separation efficiency even when the feed composition fluctuates. The system’s intelligent control panel provides real-time monitoring of parameters such as torque, flow rate, and vibration, ensuring stable operation and preventing overload. This adaptability makes it suitable for both primary sludge thickening and final dewatering stages in wastewater treatment lines.

3. Sustainable and Cost-Effective Operation

The dewatering centrifuge significantly reduces the moisture content of sludge, lowering transportation and disposal costs. By improving the dryness of the discharged solids, it minimizes waste volume and supports sustainable resource management. Additionally, the GNLW364-VFD’s energy-efficient drive system helps pharmaceutical plants reduce power consumption and carbon footprint, aligning with global trends toward greener production.

In summary, the GNLW364-VFD dewatering centrifuge is a proven and trusted solution for pharmaceutical wastewater treatment. With its high efficiency, flexibility, and compliance with industry standards, it plays an essential role in helping pharmaceutical facilities achieve cleaner, safer, and more sustainable wastewater management.

What are the frequently asked questions about decanter centrifuge?

　　 Decanter centrifuge is a kind of centrifuge. It is a kind of mud-water mixture that enters the drum through the feed pipe and the screw discharge port. Under the action of the centrifugal force generated by the high-speed rotation of the main engine, the solid particles with larger specific gravity are deposited on the inner wall of the drum, and the spiral blades moving relative to the drum successively scrape the solid particles deposited on the inner wall of the drum and push them out. The slag outlet, the separated clear liquid flows out of the drum machine through the opening of the weir plate.

1. What are the main components of the screw conveyor in the decanter centrifuge?

The screw conveyor of the Decanter centrifuge contains two parts: the drum and the screw, and the screw includes the cylinder and the pusher blade. On the cylinder, there is a feed end and a clear liquid outlet end, which are used to feed materials and flow out the clear liquid after separation.

2. Why can the Decanter centrifuge be used in petrochemical and waste treatment?

Because the decanter centrfuge has the characteristics of compact structure, low energy consumption, strong production capacity, and good adaptability to materials. And with the continuous development of science and technology, the centrifuge has been greatly improved and advanced in terms of structure, performance and technical parameters, and its separation effect has also been improved, so it is used in petrochemical and The treatment of the three wastes is very suitable.

3. Can the decanter centrifuge be used as the main engine of sludge dewatering?

If it is used for sludge dewatering, it is very suitable, and if it has a large aspect ratio and a fully enclosed operation is selected, then it can have a good use effect, because its It has advantages that other sludge dewatering equipment does not have.

4. What is the process of desilting using a decanter centrifuge in a sewage treatment plant?

In the wastewater treatment plant, in the treatment of activated sludge, the whole process of using a decanter centrifuge to desludge is to drive the high-speed rotation of the sludge through a high-speed rotating drum, and then generate centrifugal force to make the sludge The sedimentation of the solid particles accelerates and concentrates on the wall of the drum. Then, through the spiral, the formed mud cake is scraped to the small end of the rotating drum, so that it can be discharged, thereby completing the desliming work.

5. What is the main use of the decanter centrifuge? In addition, what are the unloading conditions of the decanter centrifuge?

Decanter centrifuge is mainly used to remove impurities and suspended solids in the liquid to achieve the role of purification. The general decanter centrifuge, its discharge conditions, mainly including cone angle and bowl speed.

GN Separation – Centrifuges with Truly Wide-Ranging Applications

At GN Separation, we take pride in delivering high-performance centrifuges to over 90 countries worldwide. What sets our equipment apart is not just its efficiency and reliability, but its remarkable versatility. From heavy industry to fine chemical processing, GN centrifuges are applied across a vast array of sectors, proving that one solution can meet many challenges.

Fig. 1 Decanter Centrifuge

Oil & Gas – Solids Control and Waste Management
In the oil and gas industry, GN centrifuges play a critical role in drilling mud solids control, oil sludge separation, and cuttings treatment. Our machines efficiently remove fine solids, stabilize drilling fluids, and reduce environmental impact—supporting both onshore and offshore operations.

Environmental Protection and Wastewater Treatment
GN centrifuges are widely used for municipal and industrial wastewater treatment, sludge dewatering, and oil-water-solid separation. They help reduce disposal costs, improve environmental compliance, and enable resource recovery, making them indispensable tools for sustainable operations.

Mining and Construction
From tailings dewatering and sand washing to tunneling slurry separation and construction site mud recycling, GN centrifuges deliver reliable performance in even the most demanding environments. Wear-resistant materials and robust designs ensure high efficiency under challenging conditions.

Chemical, Pharmaceutical, and Food & Beverage Industries
GN centrifuges adapt seamlessly to high-viscosity chemical slurries, pharmaceutical production, fruit juice clarification, plant oil purification, and biofuel processing. Different models accommodate diverse materials, demonstrating the flexibility that sets GN apart.

Specialized Applications Across Industries
Beyond these core sectors, GN equipment is applied in marine wastewater treatment, industrial waste recovery, and recycling operations, highlighting the broad applicability of our technology.

With a global reach, innovative design, and unmatched reliability, GN centrifuges are more than just equipment—they are versatile solutions capable of meeting the separation needs of virtually any industry. No matter the challenge, GN Separation brings efficiency, sustainability, and adaptability to every application.

Bearing Replacement Method for Decanter Centrifuge

During operation, a Decanter centrifuge runs at high rotational speeds, which places stringent demands on its bearings. Proper bearing maintenance and replacement are crucial to ensure smooth operation, prevent damage, and extend service life of the Decanter centrifuge.
When the drum bearings show signs of wear or malfunction and require replacement, it is essential to follow the correct procedure. The following steps outline the recommended bearing replacement method to ensure safe and reliable operation.

1. Preparation and Safety

Before starting, ensure the following:

Only qualified personnel should perform disassembly and assembly.

Use professional tools designed for bearing and centrifuge maintenance.

Disconnect the centrifuge from power and follow all lockout/tagout procedures.

Clean the working area and prepare lifting devices for the Decanter centrifuge if needed.

2. Disassembling the Small-End Bearing

Remove the Pressure Plate Bolts
Begin by loosening and removing the bolts from the pressure plate located on the main pulley end.

Extract the Pressure Plate
Use jack screws to evenly push out the end pressure plate. Ensure that all screws are loaded evenly to avoid skewing or deformation.

Remove the Pulley
Using a three-jaw puller, grip the pulley and pull it out carefully.

Mark Components for Reassembly
Clearly mark the relative positions of all components (keys, sleeves, seals, etc.) to ensure correct reinstallation later.

Remove Associated Components
Sequentially disassemble the flat key, taper-end screw, bearing seat sealing ring, and O-ring.

Extract the Bearing Assembly
Place a supporting pad on the bearing end face of the bowl shaft. Then, using a puller tripod, simultaneously remove the bearing sleeve, bearing sleeve gland, bearing, and shaft sleeve as a single unit.

3. Disassembling the Big-End Bearing

The process for the big-end bearing is similar but involves additional components:

Remove the Flange Bolts
Loosen and remove the flange bolts, then take out the differential and spline shaft.

Disassemble the Shaft End Pressure Plate
Remove the bolts from the shaft end pressure plate and use jack screws to push it out evenly. Keep the applied force balanced to avoid tilting.

Remove the Bearing Assembly
Place a pad on the shaft end face, then use a three-jaw puller to remove the connecting flange, bearing seat sealing ring, and flat key.

Extract Bearing Components
As with the small end, use a tripod puller to remove the bearing sleeve, bearing sleeve gland, bearing, and shaft sleeve together.
Make clear alignment marks on the bearing sleeve for accurate reassembly.

4. Key Notes for Reassembly

Ensure all parts are thoroughly cleaned and inspected for wear or damage before reinstallation.

Apply appropriate grease or lubricant to the bearings and seals according to manufacturer specifications.

Install the components in the reverse order of disassembly, aligning all marks made earlier.

After assembly, perform a manual rotation check to confirm smooth movement before restarting the centrifuge.

5. Summary

Although the replacement procedures for the small and big end bearings are similar, careful attention to detail is essential throughout the process. Accurate marking, even force application, and the use of correct tools will ensure safe bearing replacement and help maintain the reliability and longevity of the Decanter centrifuge.