Frequently asked questions
Ordering questions and technical selection questions, answered the way we would answer them on a call.
Ordering and supply
Do you manufacture to customer drawings?
Yes — that is most of what we do. Send a drawing, or a worn sample when the drawing no longer exists. We re-draw and get your approval before production.
What is your minimum order quantity?
One piece for most wear parts. We regularly ship single replacement rolls, blades and housings.
Can you supply parts for machines made by other manufacturers?
Yes. We work from the drawing or the physical part, not from the original builder's part number.
How long does production take?
It depends on the item — wear parts and small components move faster than cast rolls or complete sections. We give a firm lead time with the quotation rather than a general estimate.
Do you handle shipping and export documents?
Yes. We ship from Qingdao port and provide the commercial invoice, packing list and bill of lading, plus certificates where the destination requires them.
Can we inspect before shipment?
Yes, and we encourage it. Factory inspection and third-party pre-shipment inspection are both welcome.
What payment terms do you work on?
Terms are agreed per order and depend on the item and the relationship. Ask when you enquire.
Do you provide installation support?
For complete lines and larger rebuilds, yes — supervision and commissioning support can be included in the scope.
Technical questions by product
What is the difference between a D-type and a standard batch hydrapulper?
A standard batch pulper has a centred rotor under a round vat. A D-type moves the rotor to one side of a D-shaped vat, so stock travels a longer path with higher turbulence. That cuts pulping time and handles wet-strength or heavily inked waste better, but takes more floor space.
How do I size a hydrapulper for my mill?
Size to peak daily furnish, not the average. A common starting point is one batch per hour with 15-20% headroom, then extend the cycle rather than oversize the vat if your waste includes wet-strength grades.
Should I use a slot cylinder or a hole cylinder?
Slots (typically 0.15-0.35 mm) for fine contaminant removal on recycled furnish. Holes (1.2-3.0 mm) where capacity matters more than fine screening. Most recycled lines run a coarse hole screen first, then a fine slot screen.
How do I keep good fibre loss down?
Match the rotor to the furnish and hold reject rate at roughly 3-8% of feed. Pushing reject rate lower than that usually trades fibre loss for debris in the accepts.
Can you match an OEM disc pattern?
Yes. Send the mounting drawing, or a worn disc if drawings are lost. We map the bar profile, groove width, dam height and taper, then cut the pattern on CNC.
How long does a set of discs last?
Disc life tracks furnish abrasiveness, specific refining energy and bar clearance far more than calendar time. Mills on clean kraft see much longer life than mills on recycled furnish carrying mineral filler.
Where does a vibrating screen sit in the stock preparation line?
Normally directly after the pulper and ahead of the high-density cleaner and fine screens. Its job is protecting downstream equipment from large rejects rather than improving pulp quality.
How is hole size chosen?
Large enough to pass the accepted fibre without hydraulic restriction, small enough to catch the rejects you actually want out. It is usually set one step coarser than the fine screen downstream.
Why specify ceramic cones instead of steel?
Ceramic liners resist abrasion from sand and glass far longer than steel or polyurethane. Wear is fastest in the high-density stage, which is where the cost of a steel cone shows up first.
How many cleaning stages do I need?
Three or four stages is normal on recycled furnish — primary, secondary, tertiary and often a fourth to recover fibre from the final rejects. Virgin pulp lines usually need fewer.
How do I know when cones need replacing?
Rising sand count in the accepts, or visible wear at the apex. A worn apex widens and lets fibre escape with the rejects, which shows up as higher fibre loss rather than as dirt in the paper.
Ceramic or polyurethane?
Ceramic where abrasion is severe and the cleaner runs high density. Polyurethane where impact resistance matters and abrasion is moderate.
What actually decides roll quality on a rewinder?
Tension profile, nip pressure and slitting setup. A falling tension curve from core to surface is the usual starting point for preventing starring on most grades.
Can it be built to my web width?
Yes. Rewinders are built to your trim width rather than picked from a fixed catalogue.
Where should an arc roll be installed?
Immediately before a nip or a winder — the point where a wrinkle would otherwise be pressed in permanently.
How is bow height selected?
By web width and how much spread is needed. Wider webs and stretchy grades need more bow, but too much bow causes edge flutter and baggy centres.
Why does roll weight matter here?
A floating roll has to follow tension changes quickly. Excess inertia makes it lag, so the correction arrives after the disturbance has already passed into the sheet.
Can you manufacture to a drawing or sample?
Yes. Send a drawing, or a worn roll for reverse engineering when drawings were lost.
What is the advantage of two blades in one holder?
The second blade is already loaded and aligned. When the working edge wears, the change is a fraction of the downtime of a single-blade holder.
Which blade material suits a couch roll?
Usually a polyethylene or composite blade — hard enough to clean, soft enough not to mark the roll cover.
How is nozzle spacing decided?
By the overlap needed at your pipe-to-fabric distance. Spacing is set so adjacent fan patterns overlap slightly, avoiding streaking as the fabric oscillates.
What causes a web to wander?
Uneven tension across the width, a crowned or worn roll, or moisture profile variation. A guide roll corrects the symptom — if the web wanders consistently, check the rolls upstream first.
How often should ropes be replaced?
On condition, not on schedule. Check for glazing, diameter reduction and broken strands — a rope that has lost diameter slips in the carriers and the tail drops.
Pneumatic or spring tensioner?
Pneumatic holds tension far more consistently as rope length changes. Spring units are simpler and suit short circuits where stretch is minimal.
What stroke and speed should be used?
Enough stroke to move the blade past the width of any single defect, and slow enough that the blade does not skate. Faster is not better — it accelerates holder wear.
Why does CD uniformity matter so much on a size press?
Uneven pickup creates a moisture streak that the dryer section cannot fully remove, which then shows as curl, strength variation or a coating defect downstream.
What information do you need to quote a dryer cylinder?
Diameter, face length, design pressure, journal dimensions, gear or bearing arrangement, and whether the syphon is rotary or stationary.
Can a worn cylinder be refurbished instead of replaced?
Often yes, if the shell thickness is still above minimum and the journals are sound. A surface regrind and re-balance is far cheaper than a new casting.
Drilled or grooved shell?
Drilled shells for dewatering duty in the press section; grooved shells where you need to carry the web without marking it. Some positions use both.
What wears out first?
The suction box seals and the shell cover. Seals are a consumable; a worn shell shows up as uneven vacuum across the width.
Why use stone rather than rubber on a press roll?
Stone resists corrosion and holds a very consistent release surface over a long life. It is harder to damage than a rubber cover, but cannot be crowned as easily.
Can you manufacture from a drawing or a sample?
Both. Drawings are preferred for tolerance control; a worn housing can be measured and redrawn when the original is unavailable.
What pressure is typical?
Enough to penetrate the felt without disturbing the fibre structure — usually set by the felt supplier, and it falls as the felt ages and compacts.
Why do nozzles need replacing if they are not blocked?
Nozzle orifices wear and fan patterns distort, which causes streaking that looks like a felt problem. Replacing nozzles on condition restores an even pattern.
Which dandy roll wire structure should I choose?
Unperforated spiral suits smooth closed sheets; double diagonal perforated wires improve drainage on faster machines; the honeycomb-like structure gives the strongest marking action and the best two-sided improvement on heavier grades.
Can a dandy roll be retrofitted to an existing fourdrinier?
Yes. It mounts above the wire between two existing rolls, needs no drive of its own and is turned by the moving sheet. Installation is mainly a question of frame space and wire run geometry.
Cast or welded-plate Yankee cylinder — which one fits my machine?
Cast HT300 is the proven choice for higher steam pressures and longlife on conventional machines. A welded-plate shell is lighter and responds faster to steam changes, which suits tissue machines with frequent grade changes; it is supplied with ASME compliance.
What documentation comes with the cylinder?
Material certificate, inspection report and dynamic balance records are provided together with delivery, so the cylinder can be registered with your notified body and insurer.
What does multi-zone crown control change compared with a fixed crown roll?
A fixed crown is correct for one line load and one temperature. A multi-zone roll re-shapes the crown as grades, speeds and coats change, so caliper and gloss stay uniform edge to edge without regrinding the roll.
Is the thermal oil heating system included?
Yes. The package includes the thermo conductive oil heating system, the hydraulic station, the multi-zone hydraulic control cabinet and the operating panels, so the calender arrives as one integrated unit.
Send us your specification
Drawing, capacity, or just the problem you are trying to solve — we quote from that, not from a catalogue.