Supplying domestic hot water to a building that rises one hundred meters or more is a mechanical problem long before it becomes a plumbing problem. The column of water alone loads the lowest floors with static pressure that a conventional low-rise distribution system was never designed to see, while the continuous hot service temperature silently attacks every joint, every elbow and every meter of pipe wall over a design life measured in decades rather than years. In this environment the pipe is not a passive conduit; it is a structural and hygienic component that must hold pressure, resist temperature, refuse to scale, and survive for fifty years without a single interruption. A three layer composite anti scaling PPR pipe extrusion equipment exists precisely because a single homogeneous pipe wall can no longer satisfy all of those duties at once.
The engineering answer is to stop asking one material to do everything and instead assign each function to a dedicated layer. A three-layer composite PPR pipe places an anti-scaling functional layer on the bore, a reinforcement or barrier layer in the middle, and a protective layer on the outside, co-extruding all three through one die in a single pass. The equipment that makes this pipe is therefore more than a pipe extrusion line with extra hoppers; it is a tightly synchronized co-extrusion system in which layer ratio, melt viscosity, die geometry and cooling rate must be controlled together. This guide explains the full picture for equipment buyers and project engineers: why high-rise hot water demands the composite structure, how the three layers function, which materials and standards apply, exactly how the production line is built, what the process window looks like, how anti-scaling performance is measured, how the pipe is integrated into a tall building, and which Faygo production lines deliver it.
Faygo, a Wanplas factory with twenty-two years of dedicated pipe and profile extrusion experience, operates three specialized factories and runs a 26,650 square metre pipe, profile and sheet plant in Zhangjiagang, only two hours from Shanghai airport. The factory holds thirteen national patents including eight invention patents, and every line leaves the workshop CE and ISO certified after seventy-two hours of continuous operation testing. As part of the Wanplas group, Faygo draws on a shared engineering and service backbone that has placed plastic machinery in more than one hundred exported regions. The three-layer PPR co-extrusion line described here is a direct application of that experience to the specific failure modes of high-rise domestic hot water.
1. Four Hardships Facing Acqua calda domestica Systems in High-Rise Buildings
A high-rise domestic hot water network is defined by four stresses that ordinary low-rise plumbing never experiences together. Each stress alone is manageable; the four acting simultaneously on a single pipe wall are what make the composite structure necessary. Understanding these four hardships is the first step in specifying the right extrusion equipment, because the equipment must be capable of producing a pipe that answers all four at once.
1.1 Static pressure at the base of a tall column
In a building one hundred meters tall, the static head of the water column at the lowest riser connection is close to one megapascal before any pump pressure is added. With distribution pumps and thermal expansion, the bottom-floor service pressure in a one-hundred-meter building commonly reaches 1.0 to 1.2 megapascal. A single-layer random copolymer pipe sized for low-rise duty would need a very thick wall to carry that pressure, which only worsens the next two problems. The composite structure lets the middle layer carry stiffness and the inner layer carry the bore condition independently, so the pressure requirement does not force an oversized, thermally sluggish wall.
1.2 Long-term continuous hot water temperature
Domestic hot water is not a gentle, intermittent service. Circulation systems hold the riser at a continuous 60 to 70 degrees Celsius so that a tap delivers hot water promptly, and safety events such as a failed mixing valve can push short-term peaks to 95 degrees Celsius. Polypropylene random copolymer tolerates this band, but sustained temperature accelerates creep, softens the wall, and accelerates every chemical reaction at the bore, including scale deposition. The equipment must therefore extrude a pipe whose long-term hoop stress rating remains adequate at elevated temperature, which is why PP-RCT with its raised minimum required strength is offered as an inner-layer option.
1.3 Scaling and biofilm formation on the bore
Hard water carrying dissolved calcium and magnesium bicarbonate deposits calcium carbonate on any surface where nucleation can start. A rough bore, a polar surface, and warm stagnant pockets are ideal nucleation sites. Over years the deposit narrows the bore, raises flow resistance, and provides a habitat for biofilm. The inner anti-scaling functional layer of the composite pipe attacks this at the source: a mirror-smooth, low-surface-energy, optionally antibacterial bore that gives calcium carbonate almost nowhere to begin. This is the single most important reason the pipe is composite rather than homogeneous, and it is the property that the extrusion equipment must hold to tight tolerance across the full length.
1.4 Fifty-year design life
I servizi di costruzione non vengono sostituiti a caso. Un riser sotterraneo in una scia di parete o un ascensore è previsto per funzionare per la vita dell'edificio, in genere cinquanta anni, senza accesso per l'ispezione e senza tolleranza per le perdite. Cinquanta anni di pressione, cicli di temperatura, movimento termico e chimica dell'acqua richiedono un tubo le cui proprietà non si alterino. Il composto a tre strati risponde a questo attraverso la selezione dei materiali, il controllo dell'espansione e una superficie esterna protetta, e l'attrezzatura di estrusione deve riprodurre questa struttura stratificata metro dopo metro senza delaminazione che potrebbe diventare un percorso di fallimento a lungo termine.
When all four hardships act on one wall at once, the only robust answer is to separate functions into layers. That separation is exactly what three-layer co-extrusion equipment is built to deliver.
2. Functional Layer Structure of the Three-Layer Composite Anti-Scaling PPR Pipe
The three-layer composite PPR pipe is engineered as three concentric functional zones, each optimized for one job and bonded to its neighbor by a compatible or tie-mediated interface. The layer ratio is deliberately imbalanced: the middle layer carries most of the wall because it carries most of the structural and barrier duty, while the inner and outer layers stay thin because they are functional skins rather than load-bearing members. The typical split is about 20 to 25 percent inner, 50 to 60 percent middle, and 20 to 25 percent outer by wall thickness.
2.1 Inner layer: the anti-scaling functional skin
The inner layer is the surface that touches the water, so its entire design goal is to make scale and biofilm unwelcome. Three mechanisms are combined. First, the bore is finished to a high smoothness with inner wall roughness Ra not more than 0.3 micrometer, compared with 0.8 to 1.5 micrometer for ordinary PPR, because fewer surface asperities means fewer nucleation sites for calcium carbonate crystals. Second, the polymer is modified for anti-fouling, either by an antibacterial additive package that suppresses microbial film or by a low-surface-energy modification that makes the water wet the wall uniformly instead of pinning droplets and deposits. Third, where temperature permits, the inner layer can be made from PP-RCT, the beta-crystal nucleated random copolymer, which raises the long-term temperature rating of the bore itself. Because this layer is thin, a premium modified compound can be used without making the whole pipe expensive.
2.2 Middle layer: reinforcement or barrier
The middle layer is the structural heart of the wall and the place where the designer chooses the dominant property the building needs. Two options dominate. The first is glass-fiber reinforced PP-R, loaded with 10 to 20 percent glass fiber, which cuts the linear expansion coefficient from about 0.15 to 0.03 to 0.05 millimeter per meter per Kelvin. For a vertical riser dozens of meters long, that reduction is decisive: it shrinks thermal movement, reduces the number and size of fixed supports and expansion compensators, and keeps the pipe from bowing in its chase. The second option is EVOH (ethylene vinyl alcohol copolymer), an oxygen barrier used when the line is part of a closed heating circuit and must prevent oxygen from diffusing through the wall and corroding metal pumps, valves and radiators. With EVOH the oxygen permeability stays below 0.1 gram per cubic meter per day, satisfying the DIN 4726 limit for oxygen-tight plastic pipes. The choice between glass fiber and EVOH is a design decision made before the line is configured, and the co-extrusion equipment supports either.
2.3 Outer layer: protection and identification
Il strato esterno è la pelle della tubazione verso il mondo. Contiene stabilizzante ultravioletto per garantire che la tubazione sopravviva al deposito sul sito e all'esposizione temporanea prima dell'incorporazione, resistenza all'abrasione per evitare che venga graffiata durante l'installazione, e identificazione tramite colore o strisce per permettere agli installatori di distinguere il composto anti-incrostazioni dal PPR ordinario a colpo d'occhio. Fornisce anche una superficie resistente all'usura per le parti della tubazione che potrebbero essere esposte nelle stanze delle centrali. Poiché è una sottile pellicola, può essere tinta o striata senza influire sulle strati strutturali o igienici, motivo per cui la tubazione composta è spesso visibilmente marcata come prodotto speciale.
2.4 Layer ratio and co-extrusion temperature matching
Holding the layer ratio constant along the full line is the central quality task of the equipment. The three melts have different viscosities and thermal sensitivities, so the co-extrusion temperatures must be matched so that no layer tries to dominate the interface. The table below shows the typical wall split and the temperature window in which the layers stay balanced. Getting this wrong is the root cause of most delamination and layer-thickness faults covered later.
| Layer | Funzione | Typical wall share | Co-extrusion temperature window | Key control point |
|---|---|---|---|---|
| Inner (functional) | Anti-scaling, smooth bore, optional PP-RCT | 20 to 25 percent | 200 to 225 degrees Celsius | Keep Ra low and layer centered on bore |
| Middle (structure) | Glass-fiber reinforced PP-R or EVOH barrier | 50 to 60 percent | 210 to 235 degrees Celsius (GF higher) | Carry hoop stress and expansion control |
| Outer (protection) | UV, abrasione, identificazione del colore | 20 to 25 percent | 195 to 220 degrees Celsius | Uniform skin, no streak or sink |
| Tie layer (where needed) | Bond PP to EVOH or GF-PP | 1 to 3 percent overall | 205 to 225 degrees Celsius | Adequate thermal match to both sides |
The art of three-layer pipe is not in the chemistry alone but in holding the layer ratio and the interface temperature steady for thousands of running hours. The equipment is judged by its consistency, not by a single good sample.
3. Material System and Standards for Three-Layer PPR Pipe
The composite pipe is only as good as the five materials that make up its layers and tie layers, and each material carries a specification that the raw-material system and the extrusion window must respect. The table below lists the core materials, their defining properties, and the roles they play. All values are typical engineering figures for pipe-grade compounds and should be confirmed against the specific compound certificate at procurement.
| Material | Defining property | Role in the composite pipe | Notes for the extrusion line |
|---|---|---|---|
| PP-R (Type 3 random copolymer) | Melt flow rate 0.25 to 0.5 gram per 10 minutes at 230 degrees Celsius and 2.16 kilogram | Base polymer for inner and outer layers | Stable barrel window 190 to 230 degrees Celsius |
| PP-RCT (beta-crystal nucleated) | Struttura minima richiesta raised to 11.2 megapascal | High-temperature inner layer option | Needs controlled cooling to develop beta crystals |
| PP-R GF (glass-fiber reinforced) | 10 to 20 percent glass fiber, lower expansion coefficient | Middle reinforcement layer | Abrasive; wear-resistant barrel and screw needed |
| EVOH (ethylene vinyl alcohol copolymer) | Ethylene content 32 to 44 mole percent, strong oxygen barrier | Middle barrier layer for heating circuits | Hygroscopic; requires dried feed and tie layer |
| Tie layer (PP-g-MAH) | Maleic anhydride grafted polypropylene | Bonds PP to EVOH or glass-fiber PP | Thin layer, tight temperature match |
3.1 Standards that govern the pipe
The finished pipe is judged against a stack of product and hygiene standards that the production line must be capable of satisfying. These are referenced as plain text only: ISO 15874 defines the PP piping system for hot and cold water installations; EN ISO 9080 governs the long-term hydrostatic strength extrapolation that sets the service life basis; DIN 8077 and DIN 8078 specify dimensions and the general quality requirements for PP pipes; GB/T 18742 is the Chinese national standard family for PP-R piping; ASTM F2389 covers PP pressure pipe for plumbing; NSF/ANSI 61 and NSF/ANSI 61-G certify the material for contact with drinking water; and EU 10/2011 regulates plastic food-contact materials, which for potable water means the additive package must stay within migration limits. The extrusion equipment does not itself certify the pipe, but it must be able to hold the dimensional and property consistency those standards demand.
3.2 SDR series and the pressure-temperature relationship
The standard dimension ratio, SDR, is the ratio of outside diameter to wall thickness and it sets the pressure class. For a given material the lower the SDR the thicker the wall and the higher the pressure rating. The table below shows common SDR values for PP-R composite pipe and the indicative pressure class at representative service temperatures. Pressure ratings decline with temperature because the polymer creeps faster when warm, which is exactly why the high-rise hot water duty must be read at 60 to 70 degrees Celsius, not at the 20-degree-Celsius catalog value.
| SDR. | Wall thickness ratio | Indicative PN at 20 degrees Celsius | Indicative PN at 60 degrees Celsius | Indicative PN at 70 degrees Celsius | Indicative PN at 80 degrees Celsius |
|---|---|---|---|---|---|
| SDR 6 | Thick wall | PN 20 | PN 10 to 12 | PN 8 to 10 | PN 6 to 8 |
| SDR 7.4 | Thick wall | PN 16 | PN 8 to 10 | PN 6 to 8 | PN 5 to 6 |
| SDR 9 | Medium wall | PN 12.5 | PN 6 to 8 | PN 5 to 6 | PN 4 |
| SDR 11 | Medium-thin wall | PN 10 | PN 5 to 6 | PN 4 | PN 3.2 |
I valori di pressione sopra sono indicativi per il piano, non un sostituto per il calcolo del carico di progetto da ISO 15874 utilizzando le proprietà a lungo termine dei composti. Illustrano il punto critico: un tubo che è PN 20 a temperatura ambiente può essere solo PN 8 a acqua calda continua a 70 gradi Celsius, e la struttura del composto è ciò che consente alla strato intermedio di recuperare il margine senza espandere la parete che restringe il diametro.
4. Three-Layer Co-Extrusion Line: Main Extruder and Co-Extruders
The heart of the production line is the extrusion group: one main extruder that delivers the bulk middle-layer melt, plus two co-extruders that lay down the thin inner and outer skins. Because the layers differ in volume by an order of magnitude, the machines are sized accordingly. The main extruder is a large single-screw unit; the skin extruders are small, precise single-screw units whose job is layer placement rather than bulk output.
4.1 Main extruder: single-screw with barrier screw
The main extruder uses a single screw of diameter 45 to 90 millimeter with an L/D ratio of 30 to 33 and a PP-specific barrier screw. The barrier section separates molten and solid polymer so that the melt delivered to the die is homogeneous and fully plasticized, which matters enormously for a glass-fiber or mineral-modified middle layer that must not contain unmelted agglomerates. Throughput scales with screw diameter and runs from about 120 kilogram per hour on the smallest main machine to about 800 kilogram per hour on the largest, which covers the full diameter range from 20 to 160 millimeter. The barrel is heated in independently controlled zones so the temperature profile can be tuned for PP-R, PP-RCT or the higher-temperature glass-fiber compound. For the glass-fiber middle layer the barrel and screw flight surfaces use wear-resistant treatment because glass fiber is abrasive and will otherwise erode the metering section within a season.
4.2 Two co-extruders for the functional skins
The inner anti-scaling layer and the outer protective layer are each fed by a dedicated co-extruder of 30 to 50 millimeter diameter. These machines run at low output but must be metered with high stability because a one-percent drift in skin throughput changes the layer ratio and can shift the smooth inner surface off-center. They use the same barrier-screw philosophy in miniature, with precise temperature control so the thin functional compounds, some of which contain heat-sensitive antibacterial additives, are not degraded. When the middle layer is EVOH, one of these co-extruders may instead feed the tie layer or the barrier itself, and the die distributes the layers accordingly.
4.3 Equipment specification table
The table below summarizes the extrusion group for a representative three-layer line. Exact values shift with diameter range and layer choice, but the architecture is constant across the Faygo family.
| Machine | Screw diameter | L/D ratio | Screw type | Throughput | Main duty |
|---|---|---|---|---|---|
| Main extruder | 45 to 90 millimeter | 30 to 33 | PP barrier screw | 120 to 800 kg/h | Middle structural layer |
| Co-extruder 1 | 30 to 50 millimeter | 28 to 33 | Barrier screw | 10 to 60 kg/h | Inner anti-scaling layer |
| Co-extruder 2 | 30 to 50 millimeter | 28 to 33 | Barrier screw | 10 to 80 kg/h | Outer protection or tie layer |
| Melt pump (optional) | Matched to output | n/a | Gear pump | Stabilizes pressure | Layer uniformity |
4.4 Common debugging points for the extrusion group
When the layers drift, the cause is almost always in this group. A wandering inner-layer percentage usually traces to co-extruder screw speed instability or a feed starvation in the small hopper, which is why gravimetric or loss-in-weight feeding is preferred over volumetric for the skin lines. A lumpy middle layer points to insufficient plasticizing in the main barrel, corrected by raising the rear or middle zone a few degrees or by checking the barrier flight clearance. Glass-fiber streaking in the middle layer signals fiber agglomeration and calls for a review of the concentrate letdown and the screw shear. Stabilizing the extrusion group is the first task at every commissioning because every downstream station assumes a steady, well-melted feed.
5. Spiral Mandrel Co-Extrusion Die e calibrazione al vuoto
The die is where three independent melts become one pipe. It is the most unforgiving component on the line, because any mismatch in layer flow shows up permanently in the finished wall. The three-layer co-extrusion die used for this pipe is a spiral mandrel die, chosen because the spiral distribution gives the most uniform circumferential layer thickness of any die geometry.
5.1 Spiral mandrel die and layer uniformity
A spiral mandrel die feeds each melt through a helical channel that wraps around the mandrel, merging the streams gradually so the layer arrives at the die land as a uniform annular sheet rather than as discrete feed points. For three layers the die stacks three such distribution systems around a common mandrel, each fed from its extruder. The design target is layer thickness uniformity within plus or minus 5 percent around the circumference, because a bore that is thin on one side loses its anti-scaling margin and a middle layer that is thin on one side loses pressure rating. The melt flow channels are shaped so that the interfaces stay flat and do not wave; interface waviness is a classic failure where the thin layer thickens and thins in a repeating pattern along the pipe and eventually breaks through. Temperature of the die body is held tightly, because a few degrees of gradient across the die land changes local viscosity and distorts the layer geometry.
5.2 Serbatoio di calibrazione a vuoto
Immediately after the die the pipe enters the vacuum calibration tank, where it is pulled onto a sizing sleeve under vacuum so that the outside diameter and roundness are set before the wall freezes. The calibration sleeve material is chosen for low friction and good heat extraction, often a treated aluminum or a sleeved steel, and its bore is the master dimension for the pipe. Vacuum is set in the range of minus 0.02 to minus 0.06 megapascal, enough to hold the soft pipe against the sleeve without collapsing it. Cooling water in the tank is kept at 12 to 18 degrees Celsius so that the outer surface sets quickly while the core stays workable long enough to avoid internal stress. Calibration is where ovality and outside diameter are locked in, so the tank length, water temperature and vacuum level are tuned together for each diameter and line speed.
5.3 Calibration and cooling parameter table
| Parametro | Typical setting | Effect if wrong |
|---|---|---|
| Calibration vacuum | minus 0.02 to minus 0.06 MPa | Too low: ovality; too high: collapse or sink |
| Calibration water temperature | 12 to 18 degrees Celsius | Too warm: poor set, large shrinkage |
| Sizing sleeve finish | Low-friction, polished bore | Rough sleeve scores the outer skin |
| First tank length | Matugato al diametro e alla velocità | Short tank: incomplete set before haul-off |
5.4 Debugging the die and calibration
The most common die fault is circumferential layer variation, corrected by balancing the spiral channel feeds and confirming that all three extruders deliver steady pressure. Interface waviness is fought by narrowing the temperature gap between adjacent layers and by slowing the line slightly so the melt relaxes before freezing. Ovality that calibration cannot remove usually means the vacuum is uneven around the sleeve or the pipe is pulled off-center; checking the centering of the die to the tank and the vacuum porting resolves most cases. Because the die and calibration together define the pipe shape, they are commissioned together and only then handed to the cooling and pull stations.
6. Downstream: Raffreddamento, trasporto, tagliatore planetario e controllo in linea
Once the pipe leaves calibration it must be cooled through its full wall, pulled at a perfectly steady speed, cut without burr, stacked, and measured continuously. The downstream group looks simple but it is where line-speed stability and final dimensional quality are decided.
6.1 Vasca di raffreddamento a spruzzo
Dopo il serbatoio di calibrazione il tubo passa attraverso un serbatoio di raffreddamento a spruzzo, solitamente costruito in più fasi in modo che il raffreddamento sia graduale piuttosto che shock. Il raffreddamento graduale è importante per il tubo composto perché la strato di fibra di vetro e le pellicole di PP si raffreddano e si restringono a velocità diverse; un quench troppo rapido bloca lo stress interno che si manifesta successivamente come ondulazione o, peggio, come un driver di delaminazione nascosto. La temperatura della parete di uscita viene mantenuta sotto i 40 gradi Celsius prima che il tubo raggiunga il trasporto, perché un tubo caldo si allunga sotto sforzo e perde il controllo del diametro. Il spruzzo a più fasi consente anche alla linea di funzionare a una velocità maggiore per un determinato lungo del serbatoio.
6.2 Haul-off with synchronized belts
The haul-off grips the pipe between belts and pulls it at the speed that sets the final wall thickness through the draw-down ratio. For composite pipe the haul-off uses double or triple belts so the grip is distributed and the thin outer skin is not crushed, and the traction force and line speed are held in synchronization to within plus or minus 0.5 percent. A drift in pull speed is the fastest way to make the wall thickness wander, because every percent of speed change is a percent of wall thickness change at the die. Belt pressure is tuned so the pipe is held without marking, and the drive is a closed-loop servo system referenced to an encoder on the belt.
6.3 Planetary cutter and collection
Il tagliatore planetario viaggia con il tubo mentre taglia, quindi il taglio viene fatto senza fermare la linea e senza burr. Un anello rotante di lame orbita il tubo alla velocità della linea, dando una faccenda tagliata quadrata e pulita. La squadratura del taglio è importante perché le estremità del tubo devono essere saldate a fusione, e un'estremità obliqua crea una connessione debole. Dopo il taglio, la lunghezza cade su un carrello di inclinazione o viene trasportata a una stazione di raccolta dove viene stoccata per la trasmissione alla zona di test e imballaggio. Perché il tubo composto è più pesante per metro rispetto a una parete a strato singolo dello stesso diametro, il sistema di raccolta è dimensionato per il peso effettivo finito, non per un tubo di riferimento leggero.
6.4 Online inspection
Modern lines carry continuous inspection rather than batch sampling alone. Ultrasonic thickness gauges scan the wall and can report each layer’s thickness if the layers have distinct acoustic properties, laser gauges measure the outside diameter with micrometer accuracy, and cameras or probes sample the inner wall smoothness to confirm the anti-scaling finish. A hydrostatic test bench sits at the end of the line or in the test bay to confirm pressure rating on a representative sample. The inspection data feeds a closed-loop wall-thickness control that nudges the haul-off speed or extruder outputs to hold the target wall, so the pipe stays in tolerance across the whole production run rather than only at the start.
| Downstream station | Key parameter | Accepted tolerance |
|---|---|---|
| Spray cooling | Outlet wall temperature | below 40 degrees Celsius |
| Haul-off | Speed and traction sync | within plus or minus 0.5 percent |
| Planetary cutter | Cut face squareness | perpendicular within 1 degree |
| Online gauge | Outside diameter and wall | continuous, closed-loop corrected |
7. Process Parameter Tables for Three-Layer Co-Extrusion
La finestra di processo è l'insieme di temperature, pressioni e velocità che mantiene tutte le tre strati nella loro giusta proporzione e il tubo nella sua giusta dimensione. I tabellini qui sotto sono la fonte di riferimento utilizzata al momento della messa in funzione e durante i cambi di produzione. Sono valori indicativi di ingegneria; i numeri esatti sono definiti su ogni linea contro i composti scelti.
7.1 Barrel and die temperature profile
The main PP-R layer runs about 190 to 230 degrees Celsius across the barrel zones, with the glass-fiber middle layer run somewhat higher to keep the filled compound fluid, and the EVOH or tie layer held in its own narrow band to protect its barrier properties. The die body sits at the top of the range so the melts stay uniform as they distribute. Too cold and the layers fail to fuse; too hot and the additives degrade and the interface smears.
| Zone | PP-R inner / outer | Glass-fiber middle | EVOH / tie middle |
|---|---|---|---|
| Feed zone | 190 to 200 degrees Celsius | 195 a 210 gradi Celsius | 195 to 205 degrees Celsius |
| Compression zone | 205 a 215 gradi Celsius | 210 to 225 degrees Celsius | 205 a 215 gradi Celsius |
| Metering zone | 210 to 225 degrees Celsius | 220 to 235 degrees Celsius | 210 to 220 degrees Celsius |
| Die body | 215 a 230 gradi Celsius | 220 to 235 degrees Celsius | 215 to 225 degrees Celsius |
7.2 Melt pressure, vacuum, cooling and speed matching
La pressione della fusione al matrone è mantenuta tra 15 e 30 megapascal in modo che le strati siano pressati in contatto stretto e la distribuzione spiraleggiante rimanga piena. Il vuoto, la temperatura dell'acqua e la velocità della linea sono abbinati al diametro come mostrato, e il spessore della parete è mantenuto da un circuito chiuso che collega la velocità di trasporto alla parete misurata. I diametri più piccoli funzionano rapidamente; i diametri più grandi funzionano lentamente perché la massa della parete per metro è molto maggiore.
| Nominal diameter | Melt pressure | Calibration vacuum | Cooling water | Line speed | Throughput |
|---|---|---|---|---|---|
| 20 millimeter | 15 to 22 MPa | minus 0.02 to 0.04 MPa | 12 to 18 degrees Celsius | 12 to 22 m/min | 120 to 180 kg/h |
| 32 millimeter | 16 to 24 MPa | minus 0.02 to 0.05 MPa | 12 to 18 degrees Celsius | 8 to 16 m/min | 150 to 240 kg/h |
| 63 millimeter | 18 to 26 MPa | minus 0.03 to 0.05 MPa | 12 to 18 degrees Celsius | 4 to 9 m/min | 180 to 320 kg/h |
| 110 millimeter | 20 to 28 MPa | minus 0.04 to 0.06 MPa | 12 to 18 degrees Celsius | 2 to 5 m/min | 300 to 600 kg/h |
| 160 millimeter | 22 to 30 MPa | minus 0.04 to 0.06 MPa | 12 to 18 degrees Celsius | 1.5 to 3.5 m/min | 380 to 800 kg/h |
7.3 Wall thickness closed-loop control
La parete non viene impostata una volta e poi dimenticata. Il dispositivo di misurazione in tempo reale riporta il diametro esterno e la parete, il sistema di controllo le confronta con il valore di riferimento per il SDR selezionato e regola la velocità di alimentazione e le uscite dell'estrusore per eliminare eventuali deviazioni. Questo circuito chiuso consente alla linea di mantenere la tolleranza durante tutta la giornata di lavoro, anziché solo sulla prima bobina. Protege anche il costoso composto interno, perché se la strato interno inizia a sottoporre a variazioni di spessore, il circuito può compensare prima che venga perso il margine di tolleranza anti-scaling.
8. Verifying and Quantifying Anti-Scaling Performance
La dichiarazione anti-scaling è credibile solo se viene misurata nello stesso modo ogni volta e confrontata con un tubo di riferimento. Il metodo di prova e il quadro di confronto qui sotto sono quelli utilizzati per quantificare le prestazioni del strato interno e esprimere l’ampliamento come un moltiplicatore relativo invece che una promessa assoluta.
8.1 Scaling test method
L’esemplare di tubo viene montato in un circuito attraverso il quale acqua dura circola a una concentrazione di carbonato di calcio di 300 a 500 milligrammi per litro, tenuta a circa 60 gradi Celsius e fatta funzionare per 500 a 2000 ore. Alla fine si misura il spessore della strato di incrostazioni e l’incremento di massa per unità di area, si rimaa la rugosità della parete interna per verificare quanto il foro sia diventato più rugoso e si calcola la velocità di decadimento del flusso a flusso costante in base alla differenza di pressione. Un controllo antibatterico separato utilizza il metodo ISO 22196, che conta la riduzione batterica sulla superficie rispetto a un controllo. La procedura completa viene ripetuta su un tubo di PPR a strato singolo di riferimento dello stesso diametro e SDR, per garantire una confronto equo.
8.2 Comparazione con il PPR ordinario
Poiché la superficie interna del tubo composto è più liscia e ha un minor consumo energetico, il carbonato di calcio si nuclea molto meno facilmente, con il risultato di una formazione di incrostazioni molto più lenta. Il tabellino esprime l’ampliamento come un moltiplicatore della velocità di formazione di incrostazioni del PPR ordinario, che è il modo onesto per esprimere il beneficio senza suggerire un numero di durata fissa che dipende dalla composizione dell’acqua locale.
| Metric | Ordinary PPR (reference) | Composite anti-scaling PPR | Improvement |
|---|---|---|---|
| Inner wall roughness Ra | 0.8 to 1.5 micrometer | not more than 0.3 micrometer | smoother bore |
| Scale mass increment | Reference value | lower multiple of reference | >scaling rate reduced severalfold |
| Flow decay after test | Reference value | lower multiple of reference | flow retained longer |
| Antibacterial activity | none | reduced count per ISO 22196 | biofilm suppressed |
The precise multiple depends on water hardness, temperature and flow velocity, so the equipment and the material are validated against the customer’s actual water where that data is available. What the extrusion line guarantees is the surface quality that makes the lower scaling rate possible: a bore that stays smooth and centered for the full length of every pipe.
9. System Design Support for High-Rise Applicazioni
Making the pipe is only half the job; the pipe must be installed so that its properties are used correctly. The composite PPR pipe changes several design rules compared with a single-layer wall, and the equipment supplier should be able to advise on these so the finished building performs.
9.1 Zoned supply and pressure reduction
Because the base of a tall building sees 1.0 to 1.2 megapascal, the distribution is split into pressure zones, each served by its own riser and each protected by pressure-reducing valves so that no branch sees more than its rated pressure. The pipe grade and SDR are chosen per zone: lower zones use thicker SDR or PP-RCT inner layers, upper zones can use thinner walls. The co-extrusion line’s ability to hold SDR tightly is what makes this zoned design safe, because a wall that wanders thin would break the zone calculation.
9.2 Hot water circulation return
To avoid drawing cold water at every distant tap, high-rise systems use a circulation loop with a return pipe so water is always moving and always warm. Moving water scales more slowly than stagnant water, which complements the anti-scaling bore. The return loop also limits the time the pipe spends at peak temperature, extending the effective life. The pipe’s fusion joints must be planned so the loop can be balanced, and the composite pipe’s consistent wall makes joint heating predictable.
9.3 Thermal expansion compensation
Even with the glass-fiber middle layer cutting expansion to 0.03 to 0.05 millimeter per meter per Kelvin, a long vertical riser still moves with temperature, and that movement must be absorbed by expansion joints and anchored by fixed supports at planned intervals. The table gives indicative fixed-support spacing for the glass-fiber composite riser; the plain PPR value would be much shorter and would require far more anchors. Proper spacing prevents the pipe from buckling in its chase and prevents the joints from being loaded in bending.
| Diameter | Fixed support spacing (GF composite) | Compensation method |
|---|---|---|
| 20 to 25 millimeter | about 2.5 to 3.0 meter | Expansion joint at riser base |
| 32 to 40 millimeter | about 3.0 to 3.5 meter | Joint plus guide supports |
| 50 to 63 millimeter | about 3.5 to 4.0 meter | Joint plus guide supports |
| 75 to 110 millimeter | about 4.0 to 5.0 meter | Larger joint, fewer anchors |
9.4 Insulation and fusion joint parameters
The riser is insulated to hold the service temperature and to protect any exposed portions from ultraviolet. Joints are made by hot-melt fusion, with a melt temperature of 260 plus or minus 10 degrees Celsius and heating and cooling times scaled to diameter. The table below gives the indicative heating and cooling times; these are planning values and the jointing tool’s own schedule should be followed on site. Consistent wall from the extrusion line makes these times reliable, because the heater encounters the same wall thickness at every joint.
| Diameter | Heating time | Cooling time | Temperatura della fusione |
|---|---|---|---|
| 20 millimeter | about 5 seconds | about 2 minutes | 260 plus or minus 10 degrees Celsius |
| 32 millimeter | about 8 seconds | about 4 minutes | 260 plus or minus 10 degrees Celsius |
| 63 millimeter | about 18 seconds | about 7 minutes | 260 plus or minus 10 degrees Celsius |
| 110 millimeter | about 35 seconds | about 12 minutes | 260 plus or minus 10 degrees Celsius |
10. Faygo Three-Layer PPR Co-Extrusion Linea di produziones
Faygo offers the three-layer composite PPR capability as configurations of its PP-R/PE-RT pipe extrusion line, the same product family that covers PP-R and PE-RT pipes from 16 to 160 millimeter. Two configurations cover the diameter bands most relevant to high-rise domestic hot water, and both are built on the extrusion group, spiral mandrel co-extrusion die, vacuum calibration, spray cooling, synchronized haul-off, planetary cutter and online inspection described above. The specifications below are representative; final values are confirmed against the chosen layer structure and compound.
10.1 Configurazione A: small-to-medium diameter 20 to 63 millimeter
This configuration targets the branch and riser diameters most common inside apartments and on the upper floors of a building. It pairs a mid-size main extruder with two skin co-extruders and a three-layer spiral mandrel die. The line is compact enough for a modest floor area yet covers the full range of apartment hot water piping. The smooth inner layer is produced from a dedicated hopper so the anti-scaling compound is never contaminated by the structural middle layer.
| Specification | Configurazione A (20 to 63 millimeter) |
|---|---|
| Pipe diameter range | 20 to 63 millimeter |
| Main extruder | Single-screw 60 millimeter, L/D 33, PP barrier screw |
| Co-extruder 1 (inner) | Single-screw 30 millimeter, L/D 30 |
| Co-extruder 2 (outer or tie) | Single-screw 45 millimeter, L/D 30 |
| Throughput | 120 to 260 kilogram per hour |
| Line speed | 4 to 22 meter per minute (by diameter) |
| Potenza installata | about 145 kilowatt |
| Line length | about 28 meter |
| Co-extrusion layers | 3 (inner functional, middle GF or EVOH, outer) |
| Calibration method | Manicotto di calibrazione al vuoto, water 12 to 18 degrees Celsius |
10.2 Configurazione B: large diameter 75 to 160 millimeter
This configuration serves the main risers and plant-room headers where wall mass and throughput are highest. It uses the largest main extruder in the family and the full three-layer die, and it is the line chosen when a project needs both the glass-fiber expansion control and the anti-scaling bore in one product at volume. The higher installed power and longer line reflect the greater cooling and pull load of the heavy large-diameter pipe.
| Specification | Configurazione B (75 to 160 millimeter) |
|---|---|
| Pipe diameter range | 75 to 160 millimeter |
| Main extruder | Single-screw 90 millimeter, L/D 33, PP barrier screw |
| Co-extruder 1 (inner) | Single-screw 40 millimeter, L/D 30 |
| Co-extruder 2 (outer or tie) | Single-screw 50 millimeter, L/D 30 |
| Throughput | 320 to 800 kilogram per hour |
| Line speed | 1.5 to 10 meter per minute (by diameter) |
| Potenza installata | about 280 kilowatt |
| Line length | about 36 meter |
| Co-extrusion layers | 3 (inner functional, middle GF or EVOH, outer) |
| Calibration method | Manicotto di calibrazione al vuoto, water 12 to 18 degrees Celsius |
Entrambi i configurazioni condividono il sistema di controllo intelligente di Faygo, che consente agli operatori di impostare i parametri liberamente e di regolarli in tempo reale, e entrambe utilizzano componenti elettrici di marca riconosciuti a livello internazionale per la affidabilità. Escono dalla fabbrica dopo il test di funzionamento continuo standard di settanta e due ore, che è dove la consistenza delle strati e il controllo della parete a circuito chiuso sono provate prima della spedizione.
11. Requirement-to-Model Selection Guide
The right configuration follows directly from the project’s diameter range, the required layer structure and the target output. The table below maps common high-rise hot water requirements to the Faygo PP-R/PE-RT pipe extrusion line configuration that satisfies them. Where the duty is a closed heating circuit rather than potable hot water, the EVOH barrier middle layer is selected instead of glass fiber.
| Diameter range | Layer structure | Target output | Recommended Faygo configuration |
|---|---|---|---|
| 20 to 32 millimeter | 2-layer anti-scaling (inner functional plus outer) | 120 to 180 kg/h | PP-R/PE-RT line, Configurazione A, 2-layer mode |
| 20 to 63 millimeter | 3-layer with glass-fiber middle | 180 to 260 kg/h | PP-R/PE-RT line, Configurazione A, 3-layer mode |
| 20 to 63 millimeter | 3-layer with EVOH barrier middle | 180 to 260 kg/h | PP-R/PE-RT line, Configurazione A, EVOH mode |
| 75 to 110 millimeter | 3-layer composite, GF or EVOH | 320 to 600 kg/h | PP-R/PE-RT line, Configurazione B |
| 110 to 160 millimeter | 3-layer composite, GF middle | 500 to 800 kg/h | PP-R/PE-RT line, Configurazione B, high-output |
| 20 to 110 millimeter | 3-layer with PP-RCT inner, high temp | 180 to 600 kg/h | PP-R/PE-RT line, Configurazione A or B with PP-RCT option |
For projects that also need other pipe families, the Wanplas group can supply adjacent extrusion lines so a single supplier covers the whole building services package, but on the faygo-china.com scope the recommendation stays within the Faygo pipe and profile extrusion product range.
12. Common Defects and Countermeasure Matrix
Even a well-designed line develops faults, and the composite structure has a few failure modes that single-layer pipe does not. The matrix below is the field reference used during commissioning and routine production. Each fault lists the likely cause and the corrective action, ordered so the operator can move from symptom to fix without guesswork.
| Defect | Likely cause | Countermeasure |
|---|---|---|
| Layer thickness uneven | Co-extruder speed drift, unbalanced spiral feed | Stabilize skin extruder with gravimetric feed; rebalance die channels |
| Inner layer delamination | Tie layer insufficient or temperature mismatch | Increase tie layer; narrow temperature gap between layers |
| Inner wall scratches | Calibration sleeve damage, foreign particles | Polish or replace sleeve; filter melt and clean feed |
| Outside diameter fluctuation | Haul-off speed drift, vacuum unstable | Recalibrate servo sync; check vacuum porting |
| Ovality over limit | Off-center die to tank, uneven vacuum | Center die; balance vacuum around sleeve |
| Inner shark skin | Inner melt too cold or too fast at die land | Raise inner layer die temperature slightly; reduce speed |
| Bubbles and water marks | Moisture in feed, especially EVOH | Dry EVOH and hygroscopic compounds; check hopper |
| Cut burr | Dull cutter blade, wrong tracking speed | Sharpen or replace blade; match cutter to line speed |
| Hydrostatic test failure | Wall below target, weak fusion, voids | Enforce closed-loop wall control; review joint quality |
Most of these faults trace back to the same two themes: unstable extruder metering and poor temperature matching at the interface. The Faygo line’s gravimetric feeding on the skin extruders and its tight die temperature control are the design features that prevent the majority of them before they start.
13. Assistenza e supporto From Faygo
A production line is a long-term asset, and the value of the supplier is measured over the years after commissioning as much as at the moment of purchase. Faygo, as a Wanplas factory, delivers the group’s shared service承诺 through a defined support program that begins before shipment and continues through the full operating life of the line.
13.1 Testing and commissioning
Every line is run for seventy-two hours of continuous operation at the factory before it is approved for shipment, so that layer consistency, wall control and line speed are proven under load rather than on paper. After arrival, Faygo engineers assist with installation and commissioning, bring the line to rated output, and run a trial production and sampling batch so the customer sees finished pipe before acceptance. The trial batch is also the moment to validate the anti-scaling bore finish and the hydrostatic sample against the project specification.
13.2 Spare parts, training and remote operation
The Wanplas group policy provides USD 500 free spare parts per year for the line, with warranty replacement for damaged parts inside the warranty period. Operators receive hands-on training in setup, changeover and routine maintenance, and the intelligent control system supports remote monitoring so Faygo engineers can read process data and help resolve faults without delay. Because the control platform stores recipes, a diameter or layer change can be repeated reliably once it has been tuned.
13.3 Open factory and project services
Faygo welcomes customer visits to its Zhangjiagang plant, where the 26,650 square metre facility, the three specialized factories and the running lines can be inspected directly. Beyond the machine itself, Faygo offers factory consulting covering water and electricity design, three-dimensional workshop layout, worker configuration and training, and new-factory or capacity-expansion projects. For customers who need a complete building-services pipe package, the Wanplas group can coordinate adjacent extrusion lines so the whole scope is sourced and supported under one engineering responsibility.
Domande frequenti
Perché utilizzare una struttura a tre strati in composito invece di un tubo PPR a strato unico per il caldo sanitario in edifici di altezza?
Un tubo PPR a una sola strato gestisce la pressione e la temperatura, ma non può controllare simultaneamente la formazione di incrostazioni, l'ingresso di ossigeno, l'espansione lineare e la contaminazione della superficie. Il composto a tre strati separa le funzioni: una strato funzionale interna anti-incrostazioni mantiene il foro lisso, una strato intermedia in fibra di vetro o EVOH controlla l'espansione o la permeabilità all'ossigeno, e una strato protettivo esterno resiste agli UV e ai danni meccanici. Questa divisione consente di ottimizzare ogni strato senza compromettere gli altri.
What is the difference between a glass-fiber middle layer and an EVOH middle layer?
Glass-fiber reinforced PP-R lowers the linear expansion coefficient from about 0.15 to 0.03 to 0.05 millimeter per meter per Kelvin, which stabilizes long vertical risers and reduces the number of fixed supports. EVOH (ethylene vinyl alcohol copolymer) is an oxygen barrier used in closed heating circuits to stop oxygen diffusing through the wall and corroding metal pumps and valves, keeping oxygen permeability below 0.1 gram per cubic meter per day per DIN 4726. Many domestic hot water lines choose the glass-fiber version; heating systems choose EVOH.
How is anti-scaling performance of the inner layer verified?
The standard approach circulates hard water with 300 to 500 milligram per liter calcium carbonate at about 60 degrees Celsius for 500 to 2000 hours, then measures scale layer thickness, mass increment, inner wall roughness and flow decay. Antibacterial function is checked by the ISO 22196 method. The result is compared against a reference single-layer PPR pipe to express scaling rate reduction as a relative multiple rather than an absolute figure.
What extruder configuration does a three-layer PPR co-extrusion line use?
La linea utilizza un unico estrusore singolo, solitamente di diametro 45 a 90 millimetri con L/D 30 a 33 e un tornello di barriera di PP, oltre a due co-estrusori di 30 a 50 millimetri per la strato funzionale interna e la strato o la strato esterna. Un matrone di estrusione a spirale combina i tre fusibili in un tubo con uniformità di strato entro plus o minus 5 percenti.
Which Faygo production line fits a given diameter and layer structure?
Per il tubo PPR a tre strati da 20 a 63 millimetri, la linea di estrusione Faygo PP-R/PE-RT nella configurazione di piccolo a medio diametro copre una produzione di 120 a 260 chilogrammi all'ora. Per il tubo a tre strati composto da 75 a 160 millimetri, la configurazione di grande diametro copre una produzione di 320 a 800 chilogrammi all'ora. Entrambe sono configurazioni della stessa famiglia di prodotti della linea di estrusione Faygo PP-R/PE-RT e condividono la calibrazione al vuoto, il taglio planetario e l'ispezione in linea.
Quali sono le temperature di fusione e le condizioni di calibrazione tipiche per il PPR a tre strati?
Le strati di base PP-R funzionano circa 190 a 230 gradi Celsius nelle zone del cilindro, con la strato di fibra di vetro o EVOH funzionando leggermente più alta per corrispondere alla viscosità. La pressione della fusione al matrone è di 15 a 30 megapascal, la calibrazione del vuoto è impostata tra minus 0,02 e minus 0,06 megapascal con l'acqua di raffreddamento a 12 a 18 gradi Celsius, e la temperatura della parete di uscita dal serbatoio a spruzzo rimane sotto i 40 gradi Celsius prima del trasporto.
Come Faygo supporta l'installazione e l'assistenza post-vendita per una linea completa?
Ogni linea viene testata per 72 ore di funzionamento continuo prima della consegna, poi gli ingegneri aiutano con l'installazione e la messa in servizio, la produzione di prova e lo smaltimento. La politica del gruppo Wanplas prevede 500 dollari di pezzi di ricambio gratuiti all'anno, oltre alla sostituzione garantita per i pezzi danneggiati durante il periodo di validità, il supporto tecnico 24 ore su 24, 7 giorni su 7, la formazione degli operatori e la benvenuta aperta della fabbrica per le visite dei clienti e gli audit.
Conclusione
The domestic hot water system of a one-hundred-meter building asks more of its pipe than any low-rise network: it demands pressure resistance at the base, temperature endurance at the top, a bore that refuses to scale for fifty years, and a wall that does not buckle as it heats and cools. A three-layer composite anti-scaling PPR pipe answers all four by assigning each duty to its own layer, and the extrusion equipment that makes it is a synchronized co-extrusion system built around a stable extrusion group, a spiral mandrel die, vacuum calibration, steady haul-off and continuous inspection.
Faygo, a Wanplas factory with twenty-two years of pipe and profile extrusion experience, builds this capability into its PP-R/PE-RT pipe extrusion line in configurations covering 20 to 160 millimeter, with the layer structure, throughput and control needed for genuine high-rise duty. Every line is proven over seventy-two hours before shipment, supported by the Wanplas group’s USD 500 free spare parts per year policy, remote operation assistance and open-factory access.
If you are specifying equipment for a high-rise domestic hot water project, send us your diameter range, target output, layer structure and local water chemistry. Our engineering team will return a tailored line configuration, arrange a trial production and sampling at our Zhangjiagang plant, and walk you through commissioning and operator training so the pipe you make meets the building’s fifty-year expectation from the first meter to the last.
