TwinRoll Press & Compact Press Maintenance

On-site maintenance and refurbishment for pulp washing and dewatering presses

Wash presses are critical components in modern pulp washing and dewatering processes. Continuous operation under high mechanical loads, moisture, chemicals and abrasive process conditions gradually affects drums, sealing surfaces and other mechanical components.

PR Rolls provides specialised on-site maintenance and refurbishment services for Valmet and Andritz presses.

Our services focus on restoring worn or damaged components directly at the pulp mill wherever technically appropriate, combining practical press maintenance expertise with PR Rolls' capabilities in:

• On-site machining
• Grinding and surface restoration
• Dimensional restoration
• Industrial coatings
• Measurement and inspection
• Alignment
• Mechanical maintenance
• Refurbishment of suitable components

The objective is to restore critical press components for reliable continued operation while reducing unnecessary dismantling, transportation and production downtime.

Inspect → Measure → Repair → Restore → Verify → Return to production

Maintenance of Pulp Wash Presses

Maintain the mechanical condition behind efficient washing and dewatering

Twin-roll and compact wash presses combine mechanical dewatering with pulp washing in demanding continuous-production environments.

Valmet presses use two press rolls and a variable nip as part of the washing and final dewatering process. Andritz  press equipment similarly combines washing and final pressing, using perforated drums as central process components.

Over time, wear and deterioration can affect the mechanical condition and geometry of critical press components.

Typical maintenance requirements can involve:

• Worn surfaces
• Corrosion
• Erosion
• Damaged or worn sealing areas
• Dimensional changes
• Drum surface damage
• Bearing-related wear
• Shaft and journal damage
• Misalignment
• Mechanical damage
• Localised wear or deformation

PR Rolls evaluates the actual condition of the equipment before determining the appropriate maintenance method.

The objective is not simply to replace worn parts – it is to understand why the component has deteriorated and restore the required mechanical and functional condition.

Press Maintenance

Independent maintenance services for press equipment

PR Rolls provides maintenance and refurbishment services for press equipment used in pulp washing and dewatering applications.

The press relies on the interaction between rotating press rolls, sealing systems, bearings and other mechanical components. Correct mechanical condition is therefore important for reliable press operation.

Depending on press generation, component condition and maintenance scope, PR Rolls can provide or support work involving:

• Press roll inspection
• Surface condition assessment
• Dimensional measurements
• Repair of worn surfaces
• On-site machining
• Grinding
• Shaft and journal restoration
• Sealing surface restoration
• Industrial coating
• Alignment
• Mechanical refurbishment
• Final inspection and verification

Where components can be repaired in place, PR Rolls' portable machining technologies allow corrective work to be performed directly at the mill.

For removable components requiring more extensive restoration, workshop refurbishment can complement the on-site service.

Depending on the equipment and identified maintenance requirement, PR Rolls' scope can include:

• Drum inspection
• Surface condition assessment
• Measurement
• Sealing surface inspection and restoration
• Repair of worn or damaged areas
• On-site machining
• Grinding
• Dimensional restoration
• Industrial coating
• Shaft and journal repair
• Mechanical maintenance
• Final verification

The maintenance method is selected according to the actual condition of the press and the affected component.

Press Roll & Drum Surface Restoration

Restore worn functional surfaces

Rolls and drums in pulp washing equipment operate continuously in an environment involving moisture, chemicals, pulp fibres and mechanical loading.

Over time, functional surfaces can become worn, corroded or damaged.

Where the underlying component remains mechanically suitable, PR Rolls can evaluate whether the existing surface can be restored instead of replacing the complete component.

Depending on the damage, restoration can include:

Inspection → Measurement → Machining or grinding → Surface preparation → Coating where required → Precision finishing → Verification

The objective is to restore the required geometry and surface condition while preserving the existing component wherever technically appropriate.

Sealing Surface Repair

Geometry and surface condition matter to sealing performance

A new seal cannot compensate indefinitely for a worn, damaged or dimensionally incorrect counter surface.

For this reason, press maintenance should consider both the sealing element and the surfaces against which it operates.

PR Rolls can inspect and restore suitable sealing and counter surfaces affected by:

• Wear
• Grooves
• Corrosion
• Local surface damage
• Dimensional changes
• Uneven surfaces

Depending on the application, restoration can involve machining, grinding, dimensional restoration or coating.

This creates a more complete maintenance approach:

Seal + Counter surface + Geometry + Alignment + Operating conditions

Rather than treating the seal as an isolated spare part, the complete sealing interface can be considered.

Shaft, Journal & Bearing Area Repair

Restore local wear without replacing the complete component

Press rolls, drums and other rotating assemblies depend on correctly dimensioned shafts, journals and bearing areas.

Bearing damage, corrosion, wear or previous mechanical problems can affect these precision surfaces.

PR Rolls can evaluate suitable areas for restoration using:

• On-site machining
• Grinding
• Dimensional restoration
• Metallic coating or plating
• Precision finishing

For localised dimensional damage, surface engineering technologies can provide an alternative to replacing an otherwise serviceable shaft or roll.

After restoration, the area can be machined or ground to the required final dimensions.

On-Site Machining of Wash Press Components

Bring the machining equipment to the press

Large pulp washing equipment can be difficult and time-consuming to dismantle.

PR Rolls specialises in portable machining technologies that allow suitable components to be repaired where the equipment is installed.

Depending on the component and repair requirement, on-site work can include:

• Turning
• Milling
• Grinding
• Drilling
• Line boring
• Honing and finishing
• Local dimensional restoration

On-site machining can reduce the need for:

• Extensive dismantling
• Heavy lifting
• Transportation of large components
• External workshop time
• Reinstallation work
• Extended shutdowns

Instead of bringing the component to the machine tool, PR Rolls brings the machine tool to the component.

Industrial Coatings & Surface Engineering

Protect restored surfaces against future wear and corrosion

Machining can restore dimensions and geometry, but in some applications the component also requires improved surface properties.

PR Rolls provides industrial coatings and surface engineering for requirements including:

• Wear resistance
• Corrosion resistance
• Erosion resistance
• Chemical resistance
• Dimensional restoration
• Reduced surface deterioration

Where appropriate, coating can be integrated into the repair process:

Damage assessment → Machining → Surface preparation → Functional coating → Precision finishing

The coating system is selected according to the component, substrate, wear mechanism and operating environment.

This allows the maintenance project to address not only the existing damage but also the requirements of the future operating surface.

Inspection & Condition Assessment

Determine the maintenance scope before corrective work begins

Effective press maintenance starts with understanding the actual condition of the equipment.

PR Rolls can inspect suitable press components to identify:

• Surface wear
• Corrosion
• Mechanical damage
• Dimensional deviations
• Damaged sealing areas
• Shaft or journal wear
• Geometry problems
• Other visible deterioration

Measurements can then be used to determine whether the appropriate action is:

Continue operation

Local repair

Machine or grind

Restore the surface

Recoat

Refurbish

or, where the component condition requires it,

Replace

This condition-based approach helps avoid both unnecessary replacement and insufficient repair.

Planned Shutdown Maintenance

Prepare critical press work before the shutdown begins

Wash presses are production-critical fiberline equipment. Maintenance work therefore needs to be coordinated carefully with the mill's available shutdown window.

PR Rolls can plan specialised on-site work in advance according to:

• Press type
• Identified maintenance requirements
• Component dimensions
• Damage or wear
• Required tolerances
• Site access
• Available working space
• Shutdown schedule

Equipment and personnel can then be prepared before the planned maintenance window.

Where several operations are required, PR Rolls can combine them into one coordinated project:

Inspection → Measurement → Mechanical repair → Machining → Grinding → Surface restoration → Verification

The objective is to complete the required specialist work efficiently within the available shutdown period.

Emergency Repair of Wash Press Components

Respond when unexpected damage threatens production

Not all press maintenance can be planned.

Unexpected bearing damage, surface deterioration, mechanical damage or dimensional problems can require rapid corrective action.

For suitable repairs, PR Rolls' mobile machining equipment can be transported to the mill so that the damaged component can be assessed and restored on-site.

The first step is to determine:

What has failed?

What secondary damage has occurred?

Can the existing component be safely and technically restored?

Which repair method provides the appropriate result?

Once the condition is understood, PR Rolls can determine the required machining, surface restoration or other corrective work.

The objective is not simply to perform the fastest possible repair, but to provide a repair suitable for continued operation.

Workshop Refurbishment When On-Site Repair Is Not the Best Option

Two complementary maintenance routes

Although PR Rolls specialises in on-site services, some components are better suited to workshop refurbishment.

Where a component can be efficiently removed and requires extensive mechanical work, PR Rolls' workshop capabilities can complement the field service.

Depending on the component, refurbishment can include:

• Inspection
• Measurement
• Mechanical repair
• Machining
• Grinding
• Surface restoration
• Industrial coating
• Precision finishing
• Dynamic balancing where applicable
• Final inspection

This gives the mill two alternatives:

Large or difficult-to-remove component → Repair on-site

Removable component requiring extensive refurbishment → Workshop service

The decision is based on the component and required repair – not on a predetermined service method.

TwinRoll Press & Compact Press Lifecycle Maintenance

Maintain existing equipment according to its actual condition

Pulp washing equipment represents a significant long-term production asset.

Individual components can pass through several maintenance cycles during the life of the press.

A typical lifecycle can include:

Production → Inspection → Preventive maintenance → Local repair → Continued production

As wear progresses:

Measurement → Machining → Surface restoration → Continued production

Where more extensive deterioration occurs:

Component refurbishment → Reinstallation → Continued production

Eventually, component condition may justify replacement.

The objective is to make each maintenance decision according to actual equipment condition, production requirements and technically appropriate repair options.

Independent Service for Press Equipment
PR Rolls provides independent maintenance and repair services for equipment manufactured by Valmet and Andritz.

Our services are based on PR Rolls' own expertise in industrial maintenance, on-site machining, grinding, surface engineering, measurement and component refurbishment.

PR Rolls is not the original equipment manufacturer of Valmet TwinRoll Press or Andritz Compact Press equipment, and references to these equipment names are used to identify the machinery for which PR Rolls provides maintenance services.

This independent position allows PR Rolls to approach each maintenance requirement from the actual condition of the component and the repair technologies available.

Why PR Rolls for Wash Press Maintenance?

Combine press maintenance with specialised on-site technologies

A worn press component does not always require only one type of repair.

Surface damage may also involve dimensional wear.

A sealing problem may involve a damaged counter surface.

Bearing damage may have affected a journal.

Corrosion may require both material restoration and a more suitable functional surface.

PR Rolls combines:

Inspection + Measurement + On-site machining + Grinding + Surface restoration + Industrial coating + Workshop refurbishment

This allows the repair to be built around the actual condition of the equipment.

Our broader experience in DD washer maintenance and other pulp mill equipment complements this expertise and gives PR Rolls a strong focus on critical pulp washing equipment.

The objective is not simply to replace worn parts – it is to restore the equipment for reliable continued production.

Frequently Asked Questions About TwinRoll & Compact Press Maintenance

Does PR Rolls service Valmet Presses?
Yes. PR Rolls provides independent maintenance and refurbishment services for Valmet Press equipment, including suitable on-site machining, grinding, surface restoration, measurement and component repair.

Does PR Rolls service Andritz Press equipment?
Yes. PR Rolls provides maintenance and repair services for suitable Andritz press components, including drum and surface inspection, machining, grinding, dimensional restoration and surface engineering.

Can components be repaired on-site?
Many large or difficult-to-remove components can potentially be repaired directly at the mill. Feasibility depends on the component, damage, required tolerances and available access.

Can worn sealing surfaces be repaired?
Yes, suitable sealing and counter surfaces can be inspected and evaluated for machining, grinding or other surface restoration. The correct repair depends on the type and extent of wear.

Can damaged shafts or journals be restored?
In many cases, suitable shafts, journals and bearing areas can be restored using machining and surface engineering rather than replacing the complete component. The component must first be inspected to determine whether repair is technically appropriate.

Can PR Rolls apply wear- or corrosion-resistant coatings?
Yes. Industrial coatings can be incorporated where appropriate to provide properties such as wear, corrosion or erosion resistance. Coating selection is based on the component and operating environment.

Does PR Rolls provide emergency repairs?
PR Rolls can evaluate urgent on-site repair requirements for suitable equipment. The repair method and feasibility depend on the damage, component and site conditions.

Can PR Rolls combine several operations during one shutdown?
Yes. Inspection, measurement, machining, grinding and surface restoration can be coordinated as one maintenance project where required.

Is PR Rolls an authorised Valmet or Andritz service provider?
PR Rolls provides independent maintenance services for press equipment. PR Rolls is not the OEM of these machines.

Restore Your Wash Press for Continued Production

Press equipment operates at a critical stage of pulp washing and dewatering.

When wear, corrosion, damaged sealing surfaces or dimensional changes begin to affect critical components, complete replacement is not necessarily the first solution.

PR Rolls combines on-site inspection, machining, grinding, dimensional restoration, industrial coatings and component refurbishment to restore suitable press components.

Our capabilities cover press equipment, complementing PR Rolls' broader expertise in DD washers and pulp mill maintenance.

Inspect → Identify → Repair → Restore → Verify → Return to production

Contact PR Rolls to discuss planned maintenance, refurbishment or an on-site repair requirement for your presses.