Used Skf Ball Bearing for sale (5,029)

Condition: used, SKF 23996 CA/W33 Spherical Roller Bearings – Used – Excellent Condition – 2 pcs Nodpfxjyu Rm Aj Afajla Available: 2 SKF spherical roller bearings, model 23996 CA/W33, sourced from an industrial plant and fully operational. These are high-quality components, suitable for heavy-duty applications and ideal as immediate replacement parts. Technical Specifications: - Brand: SKF - Model: 23996 CA/W33 - Type: Spherical Roller Bearing - Cage: CA (solid brass) - Lubrication: W33 (lubrication groove and holes) - High radial and axial load capacity Suitable for: - Industrial gearboxes - Hoisting/lifting systems - Steel plants and cement works - Heavy-duty machinery - Pumping and snowmaking installations Condition: - Used, but in excellent working condition - Removed from a functioning plant - Raceways and rollers in very good shape (see photos) - Protective grease applied - No significant oxidation or visible damage - Stored in original SKF crate Ready for installation or use as a strategic spare part Scope of Supply: - Complete bearings - Original SKF wooden crate - Internal protective packaging

Condition: excellent (used), Roller bearings, ball bearings, barrel bearings, bearings, rolling bearings, thrust bearings, linear ball bearings -Linear ball bearings -Inner diameter: 30 mm -Outer diameter: 47 mm -Length: 68 mm Nljdpofgyf Iefx Afaja -Price: per piece -Quantity: 117 pieces -Weight: 0.3 kg/piece

Condition: used, Ball bearings, bearings, bearing set, accurate, radial ball bearings, roller bearings -Type: 71944CTP2HUL -Lubricating groove -Bore: Ø 220 mm -Outer diameter: 300 mm -Width: 75 mm -Number: 4x bearings available Nsdjd Nw H Djpfx Afasla -Price: per piece -Weight: 14 kg

Condition: used, Cylindrical roller bearings, spherical roller bearings, deep groove ball bearings -FAG: 6218MA.C3 -Outer diameter: 160 mm -Inside diameter: 90 mm -Width: 30 mm -Price: per piece -Number: 2 pieces -Weight: 2.7 kg Njdpfx Afsd S Ibbjaola

Condition: used, Axial deep groove ball bearings, axial deep groove ball bearings, thrust ball bearings, thrust bearings -Manufacturer: FAG, axial deep groove ball bearing 51164PM, OVP Nedef S Nclspfx Afasla -Outer diameter: 400 mm -Dimension: Ø 400 x 65 mm -Weight: 18.4 kg

Condition: used, Ball bearings, deep groove ball bearings -Number: 80x stock available -Price: per piece Nedpfx Afjb A S Dkjaela -Interior diameter: Ø 10 mm -Outer diameter: Ø 28 mm -Width: 8 mm -Weight: 0.2 kg/piece

Condition: excellent (used), Axial groove ball bearings, axial groove ball bearings, axial ball bearings, axial bearings -Manufacturer: ISB, axial ball bearing 51144M Nlodpfx Asf Ngcgofaja -Main dimensions according to: ISO 9001:2000 -Outer diameter: 270 mm -Width: 37 mm -Inner diameter: 220 mm -Number: 4x ball bearings available -Price: per piece -Weight: 4.5 kg

Year of construction: 1992, condition: new, Brand NSK Model: 6203 C2 Year of construction: Unused Weight (kg) approx. 12460 gross / 11880 net Number of pieces in stock 170.280 ( approx) Made in Japan Comments single row deep grove ball bearing , packaging by 360 pieces in carton Nsdpjqa Anfefx Afasla Sales condition Please contact us for min quantity

Year of construction: 2019, condition: new, Brand NXZ Model: 6316, 6318, 6319, 6320, 6326, 6328, 30224, 30315, 30316, 30324, 30328, 30330, 32221, 32315, 32316, 32317 Year of construction: Unused Weight (kg) approx 11360 Made in China Nodpeqa An Usfx Afaela Comments Single packed or wrapped, packed in cartons by multiple pieces Selling condition Selling as full quantity only

Year of construction: 1990, condition: new, Brand SKF Type 6202-Z/QE6 Year of manufacture: Unused Weight (kg) approx. 9400 gross / 8780 net Number of pieces in stock 193.200 ( approx) Made in France Comments Contact us for min. quantity Verkoopcondities Contact us for min. quantity Nodpfxjqa Am Ts Afaola

Year of construction: 2019, condition: new, Brand C&U Group Shanghai Bearing Co Ltd Model: TM6307/41RS Year of manufacture: Unused Weight (kg) approx 6790 net Number of pieces in stock 17350 ( approx ) Made in China Comments Contact us for min. quantity Nlsdpoqa Anqjfx Afasa Terms of sale Contact us for min. quantity

Condition: good (used), Year of construction: 2005, Offer 25190 Technical Data approx.: - max. temperature 400°C - temperature control 0 - 250°C - time automatic 0 - 60 min. Nodpfx Afswp Exdeasla - working space under the yoke 320 - 200 mm - max. ball bearing weight 250 kg - drive 400 V / 12 kVA - space requirement approx. W 850 x D 600 x H 1150 mm - weight approx. 150 kg - yokes 40 + 50 + 80 mm - mobile base

Condition: used, Year of construction: 1979, Cylindrical Grinding Machine SKF with Internal Grinding Unit Hydraulic Nodpfxsgt Ea Rs Afaola

Condition: new, functionality: fully functional, power: 55 kW (74.78 HP), Year of construction: 2026, Ball Mill for Powder and Mining Plant: Structure, Function, and Technical Details A ball mill is a key grinding machine widely used in mining, metallurgy, cement, chemical, and powder-making industries. It is designed to grind various ores and other materials into fine powder through impact and attrition between steel balls and the material inside a rotating cylindrical shell. In mining plants, ball mills are essential for ore beneficiation, preparing materials for flotation, magnetic separation, or leaching processes. In powder production, they ensure uniform particle size and high surface area for further processing. Working Principle The ball mill operates on a simple yet effective principle: as the cylindrical shell rotates around its horizontal axis, the grinding media (steel or ceramic balls) are lifted along the inner wall by centrifugal force and friction. When they reach a certain height, they fall freely, striking and grinding the material below. This repeated motion causes both impact and abrasion, reducing the material to the desired fineness. The grinding process can be performed in dry or wet conditions depending on the application. Structural Composition A standard ball mill consists of several main components: Feeding part: Equipped with a feeder or screw conveyor to ensure uniform material input. Discharging part: Can be grate type or overflow type, depending on the discharge method. Rotating part: The cylindrical shell made of steel plates, lined with wear-resistant liners. Transmission system: Includes motor, reducer, small transmission gear, and electrical control. Grinding media: Steel balls or ceramic balls of different diameters for efficient grinding. The internal liner design and ball size distribution are optimized to achieve maximum grinding efficiency and minimal energy consumption. Nsdpfxoq Nf U Ee Afaola Technical Details Typical Specifications: Feeding size: ≤25 mm Discharge size: 0.074–0.4 mm Capacity: 0.65–615 t/h (depending on model and material hardness) Cylinder speed: 18–38 r/min Power: 18.5–4500 kW Liner material: High manganese steel, rubber, or alloy steel Grinding media load: 30–45% of cylinder volume Operating Modes: Dry grinding: Suitable for materials that must remain moisture-free, such as cement clinker, limestone, and quartz. Wet grinding: Common in ore beneficiation, where water or slurry improves grinding efficiency and particle uniformity. Application in Mining Plants In mining operations, ball mills are used after crushing to further reduce ore size and liberate valuable minerals. They are integrated into grinding circuits with classifiers, hydrocyclones, and flotation systems. The ground material is classified by size, and oversized particles are returned to the mill for regrinding. This closed-circuit system ensures consistent product fineness and efficient energy use. Common Applications: Gold, copper, iron, and zinc ore grinding Cement clinker and slag processing Silicate and ceramic powder production Coal and mineral powder preparation Conclusion A ball mill is an indispensable piece of equipment in both powder production and mining beneficiation plants. Its ability to grind materials into fine, uniform particles makes it vital for downstream processes such as flotation, sintering, and chemical reactions.

Condition: new, functionality: fully functional, Year of construction: 2026, Dry and Wet Ball Mill: Structure, Operation, and Technical Details A ball mill is a fundamental grinding device used in mineral processing, cement manufacturing, chemical production, and other industrial applications. It works by rotating a cylindrical shell filled with grinding media—usually steel balls—causing impact and friction that reduce materials to fine powder. Based on the grinding environment, ball mills are classified into dry and wet types, each suited for specific materials and process requirements. Working Principle Both dry and wet ball mills operate on the same mechanical principle. The rotating cylinder, driven by a motor through a gear system, lifts the grinding media and material along the inner wall. As the rotation continues, the balls fall under gravity, striking and grinding the material. The difference lies in the presence or absence of a liquid medium during grinding. Dry Ball Mill A dry ball mill is used when the material must remain moisture-free or when water could affect product quality. It is commonly applied in cement clinker, limestone, quartz, and refractory material grinding. The discharge can be either grate type or overflow type, depending on the desired fineness. Technical Features: Feeding size: ≤25 mm Discharge size: 0.075–0.4 mm Capacity: 0.65–90 t/h Liner material: High manganese steel or wear-resistant alloy Drive system: Gear-driven or direct-coupled motor Dust control: Equipped with air exhaust and dust collector Advantages: Suitable for materials sensitive to moisture No drying process required after grinding Lower corrosion risk and simpler maintenance Easier material classification and separation Limitations: Dry grinding produces more dust and heat, requiring efficient ventilation and dust collection systems. Wet Ball Mill A wet ball mill operates with water or another liquid medium added to the material. The slurry formed during grinding improves efficiency by reducing friction and preventing excessive heat buildup. It is widely used in ore beneficiation, ceramics, and chemical industries. Nlodpfxjq Nx Alj Afaea Technical Features: Feeding size: ≤25 mm Discharge size: 0.074–0.2 mm Capacity: 0.65–615 t/h Liner material: Rubber or high-chromium steel Discharge method: Overflow or grate type Auxiliary equipment: Classifier, pump, and thickener for slurry circulation Advantages: Higher grinding efficiency and finer particle size Reduced dust and noise levels Continuous operation suitable for beneficiation circuits Better control of particle uniformity Limitations: Requires drying if the final product must be in powder form and involves more complex slurry handling. The selection between dry and wet grinding depends on the material characteristics, downstream process, and environmental conditions. Dry mills are preferred for materials that must stay moisture-free, while wet mills are ideal for fine grinding and slurry-based processes. Conclusion Dry and wet ball mills share the same mechanical structure but differ in their grinding environment and application scope. The dry type offers simplicity and low maintenance for moisture-sensitive materials, while the wet type provides higher efficiency and finer output for mineral and chemical processing. Understanding their technical parameters and operational differences ensures optimal equipment selection, improved productivity, and reliable performance in industrial grinding operations.

Year of construction: 2026, condition: new, ceramic ball mill ,Batch ball mill ,also called ceramic ball mill ,it is used for fine grinding of feldspar,quartz,clay,ore and so on.The ceramic ball mill is mainly used for material mixing, grinding,uniform product fineness,and saving power.It can be dry or wet.The machine can use different liner types according to production needs to meet different needs.The fineness of the grinding operation is controlled by the grinding time ceramic ball mill Working principle Nlsdovzx Auspfx Afaea when ball mill working,steel balls inside drum will rotate with the drum to some height,and then steel balls fall down with materials to reach the point of grinding. Working Principle of Ceramic ball mill ceramic ball mill ,Intermittent ball mill grinding operation is finished in the cylinder body. When the cylinder rotates, materials ascend to a certain height and then fall along a certain path due to the balls' gravity. Two forces are generated on the balls inside. One is the force on balls through tangent direction; the other is a opposite force in the contrast to the diameter of balls, as a result of the force generated when the balls slide down. These two forces will constitute a couple for the steel balls. The balls are squeezed between the cylinder and the adjacent steel balls, so the couple can make unequal-sized friction force. The balls will orbit along with the cylinder axis and then fall down, which can produce a strong impact force on the ores in the cylinder body and, as a result, the ores will be crushed. In conclusion, the ores in the cylinder body are mainly crushed by composite effect of peeling force, impact force and extrusion force. Ceramic ball mill also named Intermittent ball mill which adopts the wet intermittent operation, is used for fine grinding and mixing the material such as feldspar, quartz, clay ceramic raw materials. The discharging and the mud size can through through 1000 sieve pore. This machine is high milling machinery, materials should be Broken in the fineness of the state into the grinding mill to get the highest efficiency and economic benefits. The cement mill is key equipment for the grinding process of the cement clinker after the crushing process of it. It is mainly used in the cement silicate product industry. After long term design and manufacture of the cement mill, our company now has series of cement mill with various specifications to meet with different requirement from our customers. Features of Cement Mill Our company adopts suitable transmission methods according to different specifications. We have brim drive and center drive as transmission form. The cylinder adopts new type step lining to increase the grinding area. And it is easily repairable and changeable. The new designed separate-chambered structure adopts flexible lifting blade and fixed lifting blade and it is easily fixed and repaired. Technical Details We have different models and options for different requirements, please contact us for more info.

Condition: new, Year of construction: 2026, power: 7.5 kW (10.20 HP), Batch ball mills find applications in various industries where the processing of materials in discrete batches is required. The versatility of batch ball mills makes them suitable for a range of applications. Here are some common batch ball mill applications: 1. Ceramics Industry: - *Glaze Preparation:* Batch ball mills are extensively used in the ceramics industry for preparing glazes. Raw materials such as feldspar, quartz, and clay are ground with ceramic balls to achieve the desired particle size for glaze formulation. 2. Chemical Industry: - *Material Grinding:* Batch ball mills are used for grinding and blending various chemical materials. This includes the production of pigments, dyes, and other specialty chemicals where precise particle size control is crucial. 3. Pharmaceuticals: - *Drug Formulation:* In pharmaceutical manufacturing, batch ball mills are used for grinding and blending powders to create drug formulations. The controlled environment provided by these mills is essential for maintaining the integrity of pharmaceutical compounds. 4. Food Industry: Nlsdpfx Aeq I N H Nefasa - *Ingredient Mixing:* Batch ball mills may find application in the food industry for mixing and grinding ingredients. This can include the production of food additives, flavorings, and other powdered or granular products. 5. Mining and Minerals Processing: - *Ore Grinding:* Batch ball mills are used in mining and minerals processing for grinding minerals and ores. The controlled grinding helps in obtaining the desired particle size for subsequent processes, such as mineral separation or extraction. 6. Paints and Coatings: - *Pigment Dispersion:* In the paints and coatings industry, batch ball mills are employed for dispersing pigments into paint formulations. Achieving a uniform particle size is crucial for the quality and appearance of the final coating. 7. Building Materials: - *Raw Material Grinding:* Batch ball mills are used in the preparation of raw materials for the production of building materials, such as cement and concrete. Grinding of materials like limestone and clay helps in obtaining the desired fineness for subsequent processes. 8. Electronic Materials: - *Ceramic Powder Processing:* In the electronics industry, batch ball mills can be employed for processing ceramic powders used in the production of electronic components and insulating materials. 9. Research and Development: - *Material Testing:* Batch ball mills are often used in research and development laboratories for testing and optimizing material formulations. They provide a controlled environment for small-scale processing and experimentation. 10. Customized Applications: - *Specialized Processes:* Batch ball mills can be adapted for various specialized processes in different industries where precise grinding and mixing are required. Custom modifications can be made based on specific application requirements. When using a batch ball mill, it's important to consider factors such as the type of material being processed, desired particle size, and the specific requirements of the end product. Additionally, following the manufacturer's guidelines and maintaining proper operating conditions are essential for efficient and effective milling processes. Technical details We have different options for different requirements, please contact our team for more info.

Year of construction: 2026, condition: new, functionality: fully functional, A cement clinker grinding mill is a specialized equipment used to grind the hard nodular clinker into fine powder, which is cement. Most cement is currently ground in ball mills and also vertical roller mills, which are more effective than ball mills. Here are key features and information about cement clinker grinding mills: 1. Raw Materials: - The main raw material for making cement is clinker, which is produced by sintering limestone and clay. Other materials such as gypsum, fly ash, or slag may also be added during the grinding process to achieve specific properties. 2. Grinding Process: - The clinker and other additives are finely ground in the grinding mill to produce cement. The grinding process is a crucial step in cement production and contributes significantly to the final quality of the product. 3. Types of Mills: - Ball Mills: Traditional ball mills are commonly used for grinding clinker. They operate by rotating a cylinder with steel grinding balls, causing the balls to fall back into the cylinder and onto the material to be ground. - Vertical Roller Mills (VRM): VRM technology has become increasingly popular for clinker grinding. These mills use a rotating table with rollers to crush and grind the clinker, providing energy efficiency and a smaller footprint compared to ball mills. Nodpfx Afoq Nfbheaola 4. Gypsum Addition: - Gypsum is often added during the grinding process to control the setting time of the cement. It prevents flash setting of the clinker and facilitates the formation of a workable and pumpable cement paste. 5. Quality Control: - Quality control measures, such as monitoring the fineness of the cement, chemical composition, and other properties, are implemented during the grinding process to ensure the final product meets the required specifications and standards. 6. Clinker Cooling: - Before grinding, the clinker is produced by heating the raw materials in a kiln. The clinker is then cooled before entering the grinding mill to prevent excessive heat build-up during grinding. 7. Dust Collection and Environmental Considerations: - Dust collectors and air pollution control systems are often employed to capture and control the dust generated during the grinding process, addressing environmental and safety concerns. 8. Packaging and Storage: - After grinding, the cement is typically stored in silos before being packaged in bags or dispatched in bulk for distribution to construction sites or for sale in the market. Cement clinker grinding mills play a crucial role in the cement production process, and advancements in technology continue to improve the efficiency and environmental sustainability of the grinding process. Technical details We have different options for different requirements, please contact our team for more info.

Condition: new, Year of construction: 2026, power: 300 kW (407.89 HP), Ball Mill for Mining & Fine Powder Making: A ball mill is a fundamental grinding device widely used in mining, metallurgy, cement, and chemical industries. It is designed to grind ores and other materials into fine powder through impact and attrition between steel balls and the material inside a rotating cylindrical shell. In mining plants, ball mills are essential for ore beneficiation, while in powder-making industries, they ensure uniform particle size and high surface area for further processing. Working Principle The ball mill operates on the principle of impact and friction. As the cylindrical shell rotates around its horizontal axis, the grinding media—usually steel or ceramic balls—are lifted along the inner wall by centrifugal force and friction. When they reach a certain height, they fall freely, striking and grinding the material below. This repeated motion breaks down the material into fine particles. The process can be carried out in dry or wet conditions depending on the application. Structural Composition A standard ball mill consists of several main components: Feeding part: Ensures uniform material input through a feeder or screw conveyor. Discharging part: Can be grate type or overflow type, depending on the discharge method. Rotating part: The cylindrical shell made of steel plates, lined with wear-resistant liners. Transmission system: Includes motor, reducer, small transmission gear, and electrical control. Grinding media: Steel or ceramic balls of various diameters for efficient grinding. The internal liner design and ball size distribution are optimized to achieve maximum grinding efficiency and minimal energy consumption. Technical Details/Typical Specifications: Feeding size: ≤25 mm Discharge size: 0.074–0.4 mm Capacity: 0.65–615 t/h (depending on model and material hardness) Cylinder speed: 18–38 r/min Power: 18.5–4500 kW Liner material: High manganese steel, rubber, or alloy steel Grinding media load: 30–45% of cylinder volume Operating Modes: Nedpfxjq Ngafj Afaola Dry grinding: Used for materials that must remain moisture-free, such as cement clinker, limestone, and quartz. Wet grinding: Common in ore beneficiation, where water or slurry improves grinding efficiency and particle uniformity. Application in Mining and Powder Production In mining operations, ball mills are used after crushing to further reduce ore size and liberate valuable minerals. They are integrated into grinding circuits with classifiers, hydrocyclones, and flotation systems. The ground material is classified by size, and oversized particles are returned to the mill for regrinding. This closed-circuit system ensures consistent product fineness and efficient energy use. In fine powder production, ball mills are used to produce materials such as silicate, ceramic powder, refractory materials, and chemical raw materials. The uniform particle size achieved by ball milling enhances product quality and performance in downstream applications. Conclusion A ball mill is an indispensable piece of equipment for both mining and fine powder making. Its ability to grind materials into fine, uniform particles makes it vital for ore beneficiation and industrial powder production. With flexible configurations, high efficiency, and reliable operation, modern ball mills provide a cost-effective and energy-efficient solution for large-scale grinding, ensuring consistent quality and productivity across diverse applications.

Condition: new, Year of construction: 2026, We have various kinds of ball grinding mill such as batch ball mill, rod mill, cement ball mill, mining ball mill, welcome to contact our team for further details according to your specific requirements. Nlodpfx Asq I Nw Iofaja

Condition: new, fuel type: electric, Year of construction: 2026, machine/vehicle number: 2700x4500, Equipment: low noise, Main Technical parameters of the ball mill Drum diameter: 2400mm Drum length: 4500mm Motor power: 320KW Max input size: 25mm Capacity:35-60 t/h Weight: 72Tons Ball loading: 30Tons Besides this model, we also have the other models like 2700x4500, 3200x4500, 1830x13000mm, and so on, and we can also offer customerization service, we can also provide complete grinding solution for various industries like cement, quartz, ore beneficiation plant, and so on, welcome to contact us for more info. A ball mill is a common grinding machine used to grind and blend materials for use in mineral processing, including ore mining and the production of silica (silicon dioxide). When it comes to ore mining and silica grinding, the characteristics of the ore and the final product requirements will play a crucial role in selecting the appropriate ball mill. Here are some considerations for using a ball mill in ore mining and silica grinding: 1. Ore Characteristics: - Hardness: The hardness of the ore determines the type of ball mill that is most suitable. Harder ores may require a more robust and wear-resistant ball mill. - Particle Size Distribution: The initial particle size of the ore affects the grinding process. Different ores may require different approaches to achieve the desired particle size. 2. Silica Grinding: - Silica Content: If the primary goal is to grind silica, it's important to consider the initial silica content and the desired final particle size. Silica grinding often requires special attention to prevent excessive wear on the milling equipment. 3. Ball Mill Type: - Overflow vs. Grate Discharge: The type of discharge from the ball mill can impact the final product and the grinding efficiency. Overflow mills are generally used for most grinding applications, while grate discharge mills are more suitable for certain types of ores. 4. Mill Size and Capacity: - Mill Diameter and Length: The size of the ball mill should be selected based on the amount of material to be ground and the desired throughput. - Capacity: Ensure that the chosen ball mill has the capacity to handle the required volume of material efficiently. 5. Grinding Media: Nlodpsq Igiijfx Afaoa - Material and Size: The choice of grinding media (balls or cylpebs) and their size depends on the hardness of the ore and the desired final particle size. Different grinding media materials can impact the purity of silica during grinding. 6. Liners and Lifting Aids: - Liners: Consider the type of liners used in the ball mill to protect the shell and optimize the grinding process. - Lifting Aids: Some mills use lifting aids to enhance the grinding action and promote better mixing of the material. 7. Control and Monitoring Systems: - Automation: Utilize control systems to automate the milling process and ensure optimal performance. - Monitoring: Regularly monitor the milling process to adjust parameters as needed for consistent and efficient operation. 8. Safety Measures: - Safety Systems: Implement safety features to protect personnel and equipment during operation. Always follow the manufacturer's recommendations and guidelines for operation and maintenance to ensure safe and efficient use of the ball mill in ore mining and silica grinding applications.

Condition: new, functionality: fully functional, Approximately 15-18 tons of batch bearings, completely new, unused, and in original packaging. Nedpfx Ajywk T Nofaela Brands include: SKF, FAG, Timken, NTN, BTC, N&R, APB, and more.

Condition: used, diameter / mm Nsdeymqtmopfx Afaola Cutting (quantity) / 0 weight / kg

Condition: excellent (used), diameter / mm Cutting (quantity) / weight / kg Electric Single-Line Pump MKF2-KW3-20003+428 – 230 V The MKF2-KW3-20003+428 is an electric single-line lubrication pump for fluid grease, designed for operation with 230 V at 50/60 Hz. It delivers 0.2 l/min at a maximum operating pressure of 30 bar. The pump is equipped with a 3-litre plastic reservoir, pressure switch, pressure gauge, and level switch. The outlet connection is G 1/4" thread. Protection class is IP 54. The permitted ambient temperature range is +10 °C to +40 °C. The pump operates in intermittent mode with a duty cycle of 20 % (operating mode S3). Nlodpoyk Im Ssfx Afaea Compatible lubricant: fluid grease, NLGI grade 000 or 00.

Year of construction: 1988, condition: new, Maker: SKF Model : 24160C CK 30/W33 Nodpfx Asdqrbhjfaola 6 pcs in stock 156 kg/ pcs