Publish Time: 2026-10-14 Origin: Site
Pressure screen slot size directly affects pulp cleanliness, screening capacity, pressure drop, plugging tendency, fiber loss, and energy consumption. A narrower slot can improve the removal of small contaminants and fiber bundles, but it also reduces the space available for accepts to pass through the screen basket. If the slot is made too narrow for the furnish and screening stage, capacity can fall, differential pressure can increase, and the basket may plug more frequently.
For this reason, the smallest available slot is not automatically the best choice. Paper mills need to select slot width according to furnish, contaminant type, pulp consistency, screening position, production capacity, rotor design, and required paper quality. Sun Hong Group supplies different pressure screen and screen-basket configurations for virgin pulp, recycled fiber, straw pulp, chemical pulp, and paper-machine approach-flow applications. Correct slot selection should balance contaminant removal with fiber yield and stable production rather than focusing on screening accuracy alone.
Pressure screen slot size normally refers to the width of the narrow opening through which acceptable pulp passes in a slotted screen basket. The slots may be machined directly into a plate or formed using wedge-wire structures, depending on basket design. During operation, pulp flows across the screening surface while pressure difference drives acceptable fibers and water through these openings. Larger contaminants, shives, stickies, plastics, and other undesirable material are retained on the feed side and discharged through the reject system.
Sun Hong's Paper Pulp Screening Equipment Inflow Pressure Screen operates with either hole or slot baskets depending on the required screening duty. Its rotor foils generate hydraulic pulses around the basket surface, which help accepted stock pass through the apertures while periodically cleaning accumulated fibers away from the slots.
Slot width is generally much smaller than typical drilled-hole diameters used in coarse screening. Fine pressure screening may use slots in ranges such as 0.10, 0.15, 0.20, or 0.25 mm, while other applications can use wider openings. These numbers should not be treated as universal recommendations because two mills using the same nominal slot width can obtain different results if furnish, basket profile, rotor clearance, consistency, pressure, and contaminant loading are different.
An important point is that slot width is not a perfect particle-size cutoff. Flexible contaminants can deform or change orientation and pass through openings smaller than one of their dimensions. Fibers can also align with the slot and pass through even though their length is much greater than the nominal opening. Pressure screening therefore separates material according to a combination of geometry, flexibility, hydraulic behavior, and aperture size rather than simple particle diameter alone.
The main reason mills select a smaller slot is to increase screening selectivity. Narrower openings reduce the probability that larger shives, stickies, plastic fragments, fiber bundles, and other contaminants will enter the accepts stream. This is especially important in fine screening and approach-flow systems where contaminants that escape the screen can move directly toward the paper machine.
For example, changing from a relatively wide slot to a finer slot can improve removal of small deformable contaminants that would otherwise pass through the basket. This can help improve pulp cleanliness and reduce contaminant loading on downstream equipment. In recycled-fiber systems, where stock may contain adhesives, plastics, coatings, and mixed fiber bundles, fine slot screening can be particularly valuable.
However, screening efficiency is not determined by slot width alone. Rotor design, basket surface profile, approach velocity, differential pressure, reject rate, and furnish consistency all influence whether contaminants actually remain on the reject side. A narrow basket installed with an unsuitable rotor can perform worse than a slightly wider basket operating under optimized hydraulic conditions.
This relationship can be summarized as follows:
Slot Change | Likely Effect |
|---|---|
Smaller Slot | Better fine-contaminant rejection |
Smaller Slot | Lower hydraulic capacity |
Smaller Slot | Greater plugging sensitivity |
Smaller Slot | Potentially higher differential pressure |
Smaller Slot | Potentially higher fiber loss |
Larger Slot | Higher throughput |
Larger Slot | Lower plugging tendency |
Larger Slot | Lower screening selectivity |
Larger Slot | Greater risk of contaminant passage |
The correct slot is therefore a compromise between pulp cleanliness and process efficiency.
Screening capacity depends partly on how much open area is available for stock to pass through the basket. Narrower slots generally reduce effective open area, so less stock can pass through the same basket surface at the same hydraulic conditions.
Sun Hong's current Inflow Pressure Screen specifications illustrate this difference. For the same machine models, listed capacity with slotted baskets is generally lower than capacity with drilled-hole baskets. This does not mean the slotted basket is less effective; it means the machine is performing a more restrictive screening duty.
The same principle appears in Sun Hong's Paper Pulp Screening Middle Consistency MC Pressure Screen. Hole-screen capacity is higher than slot-screen capacity across the current model range because larger openings allow more hydraulic throughput.
If a mill changes from a relatively wide slot to a much finer slot without increasing screening area, several effects may appear:
Accept flow may decrease.
Differential pressure may increase.
Motor load may change.
Reject concentration may increase.
Basket plugging may become more likely.
Production bottlenecks can develop.
A mill therefore cannot simply install a finer basket and assume that the original tonnes-per-day capacity will remain unchanged. Screening area and hydraulic loading need to be recalculated.
For high-capacity paper machines, this may mean using a larger pressure screen or multiple screens in parallel when very fine screening is required.
Differential pressure is the pressure difference across the screen basket between the feed side and accepts side. It provides part of the driving force that pushes acceptable stock through the slots.
When slot width decreases, resistance to flow generally increases. If the system tries to maintain the same throughput through a more restrictive basket, differential pressure may rise. Increasing pressure can temporarily maintain capacity, but excessive differential pressure creates several problems.
Higher pressure can compact fibers against the screen surface and make plugging more severe. It can also increase hydraulic losses and place additional load on the rotor, pump, and screening system. In extreme cases, the screen becomes unstable because the machine is being forced to operate outside its intended hydraulic range.
Operators often monitor differential pressure as an indicator of basket condition. If the slots gradually become covered by fibers or contaminants, resistance increases and the pressure relationship changes. Sudden pressure changes can therefore indicate plugging, abnormal reject flow, changing furnish, or other process disturbances.
The correct slot size should allow the screen to achieve required capacity without depending on excessive pressure difference.
A fine slot gives contaminants and fibers less space to pass, which improves selectivity but also makes the opening easier to obstruct. Long fibers can bridge across narrow slots, while stickies and flexible plastic fragments may become caught at the basket surface. Once a small amount of material accumulates, additional fibers can attach to it and form a mat.
Sun Hong's own pressure-screen guidance notes practical slot examples such as 0.10, 0.15, 0.20, and 0.25 mm and identifies screen-basket blockage as a common operating issue when screening conditions are not properly controlled.
The rotor is designed to reduce this risk. As the rotor foil moves close to the screen basket, it generates alternating positive and negative hydraulic pulses. The negative-pressure portion helps pull accumulated fibers away from the slot surface, keeping the apertures open. Rotor clearance and foil geometry therefore become increasingly important as slot size decreases.
Plugging risk also depends on:
Pulp consistency
Fiber length
Stickies content
Contaminant loading
Rotor speed
Rotor-to-basket clearance
Differential pressure
Reject rate
Basket surface finish
A mill experiencing frequent plugging should not automatically increase rotor speed or pressure. The underlying problem may be a slot that is too fine for the furnish or a screening stage that is receiving contaminants that should have been removed earlier.
Pressure screening must remove contaminants without discarding excessive good fiber. Narrowing the slot can improve contaminant rejection, but it can also increase the amount of usable fiber carried into the reject stream.
Long fibers or fiber bundles may have difficulty passing through very narrow slots when stock conditions are unfavorable. As reject concentration increases, more usable fiber may leave the screen together with contaminants. This reduces pulp yield and increases raw-material cost.
The economic effect can be significant. A small percentage of additional fiber loss multiplied across hundreds of tonnes per day becomes a substantial annual cost. This is particularly important in recycled-paper mills, where fiber recovery is a major part of stock-preparation economics.
The optimum slot width therefore minimizes the total cost of:
Contaminants in Accepts + Good Fiber in Rejects + Energy + Downtime
A very fine basket may produce exceptionally clean accepts but poor economics if it rejects too much usable fiber. A wider basket may maximize yield but send unacceptable contaminants downstream. The best operating point lies between these extremes.
Secondary screening of rejects can also help recover good fiber. In multi-stage systems, the first pressure screen does not need to achieve perfect fiber recovery by itself because downstream reject screening can recover part of the usable material.
Pressure-screen baskets can use either slots or drilled holes. The best choice depends on the shape and size of contaminants being removed.
A drilled-hole basket provides circular openings and is often used in coarse or intermediate screening. Because the openings are usually larger than fine slots, hole baskets typically provide higher capacity and lower hydraulic resistance.
A slotted basket uses long, narrow openings. The narrow dimension provides greater selectivity against contaminants that cannot orient or deform sufficiently to pass through the slot. This makes slot screening especially useful for fine screening.
Factor | Slotted Basket | Drilled-Hole Basket |
|---|---|---|
Screening Precision | Higher | Lower to moderate |
Typical Duty | Fine screening | Coarse/intermediate screening |
Capacity | Lower for comparable area | Higher |
Plugging Sensitivity | Higher | Lower |
Manufacturing Precision | Higher | Moderate |
Contaminant Removal | Better for many small contaminants | Better for larger contaminants |
Energy / Pressure Demand | Can be higher | Generally lower |
Basket Cost | Often higher | Often lower |
Sun Hong's Stock Preparation Spare Parts range includes both drilled-hole and slotted screen baskets, reflecting the fact that paper mills normally need different aperture designs at different screening stages.
A typical system may use holes in an earlier coarse-screening stage and narrow slots later in fine screening. This staged design protects fine baskets from large debris and allows each machine to work more efficiently.
Not all slotted screen baskets are constructed in the same way. Two common designs are milled-slot baskets and wedge-wire baskets.
A milled-slot basket is manufactured by machining narrow slots into a metal screening surface. Sun Hong's Paper Mill Wood Pulp Milled Slot Screen Basket is intended for wood pulp, cotton pulp, hemp pulp, synthetic fiber, and mixed-pulp screening. The product is mechanically and electrochemically polished to create a smoother surface and reduce fiber catching.
Wedge-wire baskets use shaped wires assembled to create precise openings between adjacent profiles. The geometry can influence the hydraulic flow entering and leaving each slot and therefore affect pressure drop, contaminant rejection, and capacity.
The nominal slot width is important in both designs, but profile shape also matters. A 0.20 mm milled slot and a 0.20 mm wedge-wire slot do not necessarily produce identical hydraulic performance because their inlet edge, channel shape, open area, and surface profile can differ.
Buyers should therefore compare:
Nominal slot width
Slot tolerance
Open area
Surface profile
Basket diameter
Basket height
Material
Surface treatment
Wear resistance
Rotor compatibility
Quoting only “0.20 mm slot basket” does not define the entire component.
The correct slot width depends heavily on the type of pulp being screened. Virgin chemical pulp normally contains a different contaminant profile from OCC or mixed recovered paper. Mechanical pulp may contain shives and fiber bundles, while recycled furnish can contain stickies, plastic fragments, coatings, tape, and other deformable contaminants.
Recycled paper often requires more intensive screening because many contaminants are flexible and difficult to remove. A plastic flake can change orientation, while a soft adhesive particle can deform under pressure. For these contaminants, narrow slots combined with suitable rotor hydrodynamics can improve separation.
Virgin pulp may allow somewhat different basket selection because contaminant loading is lower and the objective may focus more on shive removal and stock uniformity.
Fiber length also matters. Very long fibers can bridge across narrow openings or form mats when consistency is too high. Shorter fibers can pass narrow slots more easily. Furnish composition should therefore be evaluated before reducing slot width.
A useful selection process begins by identifying:
What contaminants are present?
What contaminants must be removed?
What useful fibers must be retained?
What screening stage is being designed?
What capacity must be maintained?
Only then should the final slot width be selected.
Pressure screens can be installed at several locations in stock preparation, and the correct aperture changes with screening stage.
Coarse screening removes large contaminants early in the process. Larger holes are often more appropriate because the priority is high throughput and removal of large debris rather than extremely fine purification.
Fine screening removes smaller shives, stickies, plastics, and fiber bundles. Narrow slots become more important, but the stock entering this stage should already have been cleaned of large contaminants.
Approach-flow pressure screens operate close to the paper machine. Their purpose is to protect the headbox and forming section while maintaining stable hydraulic flow. Fine slotted baskets are commonly used when paper quality requires high pulp cleanliness.
The closer the screen is to the paper machine, the greater the consequence of contaminants passing into accepts. This is why the finest practical screening is often used later in the process rather than at the very beginning.
Using a very fine slot too early can overload the basket with material that should have been removed by coarse screens and cleaners first.
Not automatically.
Cleaner pulp can reduce defects and downstream contamination, but making the slot smaller than necessary can introduce new operating problems. Lower capacity, higher pressure drop, increased reject fiber loss, plugging, greater energy consumption, and unstable screen operation can eventually reduce mill efficiency.
Paper quality depends on many other factors as well, including furnish preparation, refining, cleaners, chemical additives, headbox operation, forming, pressing, drying, and machine clothing condition.
Fine screening therefore needs to remove contaminants to the level required by the paper grade without unnecessarily restricting useful fibers.
A mill producing high-quality printing or specialty paper may justify finer screening than a mill producing certain packaging grades from recycled fiber. However, even packaging-paper mills may need strong stickies removal because deposits can cause web breaks and machine contamination.
The correct slot size should be linked to actual paper-machine problems rather than an assumption that “smaller is better.”
Slot width can influence energy consumption in several ways. Narrower slots increase hydraulic resistance and may require a larger pressure difference to maintain flow. Rotor load can also increase if fibers accumulate on the basket and the foils must continuously clean the screening surface.
If capacity falls substantially, a mill may need additional screening area or parallel screens, which increases total installed power.
The screen basket and rotor must therefore be considered as a matched hydraulic system. Sun Hong's pressure-screen rotor designs generate pressure pulses that keep the basket surface open. The company also offers rotor configurations designed around reduced energy consumption and different screening positions.
Energy should be evaluated as:
kWh per tonne of acceptable pulp
rather than only motor size.
A 75 kW pressure screen processing several hundred tonnes per day may be more energy-efficient per tonne than a smaller unit operating near its maximum hydraulic load because the basket is too restrictive.
Selecting the correct slot size contributes to energy efficiency by allowing the screen to operate within a stable pressure and flow range.
The rotor operates very close to the screen basket. Clearance determines how strongly the rotor's pressure and suction pulses act on the screening surface.
If clearance is too large, cleaning pulses may be weak and fine slots can plug more easily. If clearance is too small, hydraulic forces, wear, power consumption, and mechanical risk may increase.
Rotor foil geometry matters as well. Different foil shapes produce different pulse intensity, shear, and flow characteristics. A basket with very narrow slots may require stronger or differently shaped pulses than a basket used for relatively coarse screening.
This is why changing only the basket without evaluating rotor condition can produce disappointing results. A mill installing a new finer basket should check:
Rotor wear
Foil geometry
Rotor speed
Rotor-to-basket clearance
Bearing condition
Differential pressure
Reject settings
The pressure screen should be treated as a complete screening system rather than a basket holder.
The nominal slot width is only useful if actual slot dimensions remain consistent across the basket.
Consider a basket specified at 0.15 mm. If some parts are significantly wider, contaminants may pass through those areas more easily. If other sections are significantly narrower, local flow resistance and plugging can increase.
This creates two problems at once: poor screening quality and unstable hydraulic loading.
Fine slot manufacturing therefore requires accurate machining, forming, welding, polishing, and inspection. This is one reason very fine slotted baskets generally require more manufacturing control than coarse drilled-hole baskets.
Surface quality matters as well. Burrs, rough welds, or damaged edges can catch fibers and become starting points for plugging. Smooth basket surfaces allow fibers to move across the screening zone more consistently.
For mills purchasing replacement baskets, dimensional accuracy should include:
Slot width
Slot uniformity
Basket roundness
Basket diameter
Overall height
Flange dimensions
Support-ring position
Surface finish
A basket that physically fits the pressure screen but has inconsistent slot geometry may still produce poor process performance.
Slot size does not remain perfectly constant throughout the basket's service life. Continuous pulp flow, abrasive contaminants, rotor interaction, chemicals, and cleaning can gradually wear the screening surface.
As slots become wider, the basket may continue providing normal capacity or even appear hydraulically easier to operate, but screening efficiency can deteriorate because contaminants that were previously rejected begin passing into the accepts.
This creates a maintenance challenge. Operators may not notice a worn basket immediately because there is no obvious blockage or capacity loss. Instead, downstream contamination slowly increases.
Potential warning signs include:
More contaminants in accepts
Increased deposits downstream
Paper defects
More frequent clothing cleaning
Unexpected stickies problems
Visible basket wear during inspection
Slot measurements should therefore form part of scheduled basket inspection.
Replacing a basket only when it cracks or becomes severely damaged can allow pulp quality to deteriorate long before mechanical failure occurs.
Pressure screening is upstream of the paper machine, but slot selection can directly influence how much contamination eventually reaches the forming section.
A finer, correctly selected pressure screen can reduce the amount of shives, plastics, stickies, and fiber bundles entering the approach-flow system. This helps protect paper machine clothing, particularly forming fabrics that are exposed directly to incoming stock.
Contaminants that reach the forming section can lodge in fabric openings, interfere with drainage, create sheet defects, and increase cleaning demand. A forming fabric cleaner can remove deposits that develop during normal machine operation, but cleaning showers cannot replace proper stock preparation.
The relationship can be viewed as a sequence:
Pulp Screening → Cleaner Stock → Lower Contaminant Load → Cleaner Forming Section → More Stable Paper Machine Clothing
An air bellow used in felt or forming-fabric guiding contributes to another part of this system by helping maintain clothing alignment. It does not affect stock purity, but stable clothing movement and clean stock both contribute to paper-machine runnability.
Slot selection should therefore consider not only accepts cleanliness in the stock-preparation department but also the downstream cost of contamination on the paper machine.
Selecting an unnecessarily fine slot commonly produces operational penalties before it produces additional useful paper-quality improvement.
Possible symptoms include:
Reduced accepts capacity
Rising differential pressure
Frequent basket plugging
Higher motor load
Increased reject volume
Greater fiber loss
Lower production
More cleaning shutdowns
Unstable screening operation
The mill may respond by increasing dilution water or opening the reject valve. Both can restore operation temporarily but may increase pumping demand or fiber loss.
If these symptoms begin after changing to a finer basket, the slot specification should be reviewed before assuming that the pressure screen itself is undersized.
The correct solution may be a slightly wider slot, greater basket area, improved upstream coarse screening, a different rotor, or lower inlet consistency.
An oversized slot usually creates the opposite problem. Capacity may be high and differential pressure low, but contaminants that should have been rejected can pass through the basket.
Possible consequences include:
Dirtier accepts
More stickies downstream
Shives in stock
Higher contaminant load on cleaners
Headbox contamination
Forming-fabric deposits
Sheet defects
Web breaks
Increased paper-machine cleaning
A wider basket may therefore appear highly productive while quietly reducing pulp quality.
This is why production capacity should never be the only performance indicator. Pressure screens need to be evaluated using both throughput and accepts cleanliness.
Slot selection should follow the process requirement rather than a standard catalog number.
Start with the furnish. Identify virgin or recycled fiber, fiber length, contaminants, and consistency. Then define the screening position: coarse, fine, or approach flow. Next, determine what contaminant size and type must be removed and how much pulp the machine needs to process.
A practical evaluation should include:
Selection Factor | Question to Answer |
|---|---|
Furnish | Virgin pulp, OCC, mixed waste, straw, other? |
Screening Stage | Coarse, fine, or approach flow? |
Capacity | Required T/D? |
Consistency | What % solids enter the screen? |
Contaminants | Stickies, shives, plastics, sand, fiber bundles? |
Current Slot | What slot is currently installed? |
Accept Quality | What downstream problem needs improvement? |
Reject Rate | How much fiber can be lost? |
Differential Pressure | What operating range is available? |
Basket Area | Is current area sufficient? |
Rotor | Is rotor geometry compatible? |
Paper Grade | Packaging, tissue, printing, specialty? |
Mills replacing an existing basket should also document current performance. If the existing 0.20 mm basket plugs frequently but already produces sufficiently clean pulp, moving automatically to 0.15 mm is unlikely to solve the problem. The root cause may instead be consistency, rotor wear, excessive contaminant loading, or insufficient screening area.
If pulp quality is poor while capacity and pressure are stable, a finer slot may be justified—but only after confirming that the rest of the system can handle the additional hydraulic resistance.
Purchase price should not be the only comparison criterion because the basket is the core separation component of the pressure screen.
Buyers should compare:
Specification | What to Confirm |
|---|---|
Nominal Slot Width | mm |
Slot Tolerance | Manufacturing consistency |
Basket Type | Milled / wedge wire |
Flow Direction | Inflow / outflow |
Screening Area | m² |
Open Area | % if available |
Material | Stainless steel grade |
Surface Treatment | Polishing / wear treatment |
Basket Diameter | Must match machine |
Basket Height | Must match machine |
Flange | Position and dimensions |
Rotor Clearance | Required operating gap |
Furnish | Intended pulp type |
Capacity | T/D |
Application | Coarse / fine / approach |
A lower-priced basket with poor slot uniformity or surface finish can increase plugging and reduce screening consistency. Conversely, a premium ultra-fine basket is unnecessary if the paper grade does not require that level of contaminant removal.
The objective is not the most expensive basket. It is the basket that gives the best combination of screening efficiency, capacity, fiber yield, energy consumption, and service life.
Sun Hong Group was established in 2010 in Xuzhou, Jiangsu Province and supplies equipment and spare parts for pulp and paper production. The company's original manufacturing work focused on forming fabric, press felt, and dryer fabric before its product range expanded into pressure screens, screen baskets, rotors, cleaners, spray systems, dewatering elements, doctor blades, rolls, rotary joints, and other paper-machine components.
For pressure-screen applications, Sun Hong supplies both complete screening machines and replacement basket and rotor components. Slotted, drilled-hole, plate-type, and wedge-wire basket structures can be selected according to furnish, screening stage, required capacity, and pulp-quality target.
This broader paper-machine product experience is useful because pressure screening should not be evaluated independently from downstream operation. Poor pulp cleanliness can increase contaminant loading on fabrics and cleaning systems, while incorrect screening can also increase fiber loss or energy consumption upstream.
For replacement baskets, mills can provide the existing pressure-screen model, basket dimensions, slot width, rotor data, and operating conditions. For new screening projects, furnish, capacity, consistency, screening position, contaminant profile, and paper grade provide the basis for selecting a suitable slot configuration.
Pressure screen slot size matters because it directly changes the balance between contaminant removal and hydraulic throughput.
A smaller slot generally improves fine-contaminant rejection, but it can reduce capacity, increase differential pressure, increase plugging risk, and send more good fiber into the reject stream. A larger slot provides easier flow and higher throughput but may allow more contaminants to pass into the accepts.
The best slot is therefore not the smallest possible opening.
Mills need to evaluate furnish → contaminant type → screening stage → required pulp cleanliness → capacity → consistency → basket area → rotor design → reject rate together.
Fine slot sizes such as 0.10, 0.15, 0.20, or 0.25 mm can be appropriate in different screening applications, but the correct value depends on the actual process. Slot geometry, manufacturing tolerance, surface profile, basket wear, rotor clearance, and differential pressure can be just as important as nominal slot width.
Sun Hong Group supplies complete pressure screen equipment together with slotted baskets, drilled-hole baskets, and rotors for different pulp-screening positions. For an accurate selection, provide the existing screen model, furnish, production capacity, consistency, current slot size, contaminant problem, reject rate, operating pressure, and required paper quality. This makes it possible to improve screening performance without sacrificing unnecessary capacity or fiber yield.
Pressure screen slot size is the width of the narrow opening in a slotted screen basket through which accepted pulp passes. It is normally specified in millimeters and is a major factor controlling screening selectivity.
Fine screening applications may use slot widths such as 0.10, 0.15, 0.20, or 0.25 mm, while other applications can use different values. The correct size depends on furnish, contaminants, capacity, and screening stage.
No. A smaller slot can improve contaminant removal but also reduces throughput and can increase differential pressure, plugging, energy use, and reject fiber loss.
Yes. Narrower slots generally reduce available flow area, so capacity is usually lower than with wider slots or drilled holes when the basket area and operating conditions are otherwise similar.
Fine slots can become blocked by long fibers, stickies, plastics, fiber bundles, or excessive contaminant loading. High consistency, incorrect rotor clearance, worn rotor foils, or poor reject control can increase the problem.
Slotted baskets provide narrower openings and are commonly used for fine screening. Drilled-hole baskets normally have larger circular openings and provide higher capacity for coarse or intermediate screening.
It can. Narrow slots create greater resistance to flow, especially when the basket begins to accumulate fibers or contaminants. Maintaining the same capacity may therefore require greater differential pressure.
Yes. If the slot is too fine for the furnish, more usable fibers can remain on the reject side and leave with contaminants. The correct setting balances pulp cleanliness and fiber yield.
Rotor foils create pressure and suction pulses that help keep the slots open. Rotor shape, speed, and clearance therefore strongly influence capacity, plugging resistance, and energy consumption when fine baskets are used.
A finer slot may be appropriate when accepts contain too many small shives, stickies, plastics, or fiber bundles and the current screen has sufficient hydraulic capacity to handle the additional restriction.
A wider slot may be appropriate when the current basket creates excessive plugging, pressure drop, or fiber loss and pulp quality remains acceptable with slightly lower screening selectivity.
Yes. Abrasive pulp and long-term operation can gradually widen slots. Capacity may remain acceptable while contaminant removal deteriorates, so basket condition should be inspected periodically.
Provide the furnish, pulp consistency, screening stage, capacity, current slot width, contaminant type, accepts quality, reject rate, pressure conditions, basket dimensions, rotor information, and downstream paper grade.