How Are Polymer and Additives Fed Into a Polymer Modified Bitumen Plant, and Is Dosing Linked to Bitumen Flow?

💡 Quick answer: In a well-designed polymer modified bitumen plant, solid polymer is fed by a screw feeding system and weighed, stabilizer is added through a separate dosing unit, and the base bitumen is metered on its own line. On the STOM/SINOTO STMB-10 and STMB-20, a PLC-based control system handles the coordination. The smallest model, the STMB-6, is manual-only. Buyers should confirm this before ordering.

If you are comparing polymer modified bitumen PMB production lines, the feeding system is the part most likely to decide product quality. Feed accuracy affects softening point, elastic recovery and storage stability. It also affects how much polymer you waste. This guide explains how an SBS modified bitumen plant handles solid polymer and stabilizers. It also covers whether the feed rates follow the bitumen flow, and what to ask any SBS bitumen plant manufacturer before you buy.

The technical details below come from the STMB series of PMB plant models made by HENAN SINOTO MACHINERY (STOM Global), which handles SBS, SIS, PE and EVA modifiers.

🔧 How Does an SBS Modified Bitumen Plant Feed Solid Polymer Into the System?

Solid polymer, usually SBS in pellet or crumb form, cannot simply be poured into hot bitumen. It has to go in at a controlled rate, be wetted evenly, and then be sheared down to fine particles. A modern SBS modified bitumen plant does this in stages:

1. Screw feeding. The main components of every STMB model include a screw feeding system. It moves polymer from the hopper into the mixing zone at a steady rate instead of in lumps.
2. Static weighing. The manufacturer states that the modifier uses static weighing measurement, which it says is more accurate than dynamic weighing. Static weighing measures a fixed quantity before it is released, so the weigh cell is not disturbed by material flowing over it.
3. Twin adding channels. The SBS modifier adding system is a dual-channel design: 2×2 tph on the STMB-6, 2×3 tph on the STMB-10 and 2×4 tph on the STMB-20. Two channels give more consistent feeding and more flexibility across formulations.
4. Rapid mixing and colloid milling. Once polymer meets hot base bitumen, a rapid mixing system pre-disperses it. The colloid mill then grinds it so that, according to the manufacturer, more than 85% of particles are under 10 microns.
5. Swelling and development. The blend moves to swelling and maturation tanks, where the polymer absorbs bitumen’s light fractions and develops its network.

📌 Why this matters: Fine particles only help if the dose is right. An excellent colloid mill cannot fix a plant that under-doses or over-doses polymer. Dosing accuracy comes first, and milling comes second.

Solid Polymer Feeding at a Glance

🧪 How Are Liquid Additives and Stabilizers Dosed in a PMB Plant?

Many buyers ask about sulfur or other stabilizers because they are what keeps a PMB from separating in storage. SBS is not naturally compatible with all bitumen sources. Without a stabilizing step, polymer-rich and bitumen-rich phases can separate in a tank or tanker.

The STMB range includes a dedicated stabilizer dosing system among its main components, separate from the polymer feed. That separation is good engineering practice. A stabilizer such as sulfur is used in far smaller quantities than polymer, so it needs its own metering hardware. Otherwise small errors become large percentage errors in the recipe.

For a modified bitumen plant, good stabilizer dosing usually means:

• A separate dosing point placed after polymer dispersion, where the mixture is homogeneous enough for the additive to react evenly.
• Small-quantity accuracy. For sulfur and similar additives, the dose is typically a fraction of one percent of the blend, so the metering device must resolve small amounts.
• Temperature awareness. Stabilizers work best within a window. Thermal oil heating and the PID temperature control described below keep the mix in range.
• Adjustable recipes. Different bitumen sources and polymer grades need different stabilizer levels, so operators need to change the dose without changing hardware.

The manufacturer says its plants are compatible with polymer brands such as Kraton, Dynasol and LG Chem, and that software presets can switch production modes, for example between high-elasticity and high-viscosity asphalt.

⚠️ Buyer tip: Ask any SBS modified bitumen plant manufacturer what the stabilizer dosing device is (pump, screw or manual addition), what its rated accuracy is, and whether it is logged in the recipe. If the supplier only says “we have a stabilizer system,” ask for details in writing.

🔗 Are Feed Rates Automatically Linked to Bitumen Flow in Polymer Modified Bitumen Production?

This is the core question. The short answer is that it depends on the model and the control mode you choose. For the STOM/SINOTO range, the published information supports the following.

What the manufacturer states:

• The base asphalt metering system is a listed main component on every model, so bitumen flow is measured.
• The control system combines a PLC and an industrial computer with automatic and manual modes.
• The asphalt pump is frequency-controlled, so bitumen flow can be adjusted electronically instead of only by valves.
• The FAQ describes a PLC-controlled automatic dosing system that weighs additives precisely and reduces human error.
• Software presets allow fast switching between production modes.

The important limitation: the technical table lists the STMB-6 as manual control, while the STMB-10 and STMB-20 offer manual or automatic control. If automatic dosing linked to flow matters to you, this affects which model you choose.

📌 What “linked” should mean: In a continuous line, the polymer and stabilizer targets are set as percentages of the bitumen throughput. If the bitumen pump speeds up or slows down, the feeders should adjust in proportion, so the final blend keeps the same ratio. This is called ratio control. Confirm with the supplier that the automatic mode actually works this way and that the polymer feeder follows the bitumen flow signal in real time.

Questions to Ask About Ratio Control

The manufacturer also states that thermal oil is regulated by dual control and that a PID loop with temperature sensors and a dedicated regulating valve controls asphalt temperature. This matters for feed-rate stability, because polymer swelling depends on temperature. If the temperature swings, an accurate dose can still produce inconsistent results.

🏭 Which PMB Plant Model Fits Your Output: 10 TPH PMB Plant or 20 TPH Polymer Modified Bitumen Plant?

The STMB series is built around three capacities. The table below is from the manufacturer’s technical parameters:

Choosing a 10 TPH PMB plant. The STMB-10 (8–10 t/h) suits contractors and regional producers who supply their own paving jobs, or who make PMB for several nearby projects. It is the smallest model with automatic control, which makes it a common starting point for buyers who want automated dosing.

Choosing a 20 TPH polymer modified bitumen plant. The STMB-20 (15–20 t/h) suits larger producers and centralized supply. Its two 75 kW colloid mills can run in series or in parallel, and a double spiral-plate heat exchanger supports continuous production. The manufacturer says it can operate 24 hours a day.

Other design points that matter for a modified bitumen plant:

• Modular, container-friendly design. The plant can start producing once the pipelines and power are connected, which helps on remote or international sites.
• Insulated pipework. Rock wool covers both the bitumen and thermal oil lines to cut heat loss.
• Closed, rapid heating. The manufacturer says this limits bitumen aging.
• Wear-resistant colloid mill. The stated design life is 100,000 tons of trouble-free operation.

Modifier compatibility is broad: SBS, SIS, SBR, PE, EVA and rubber powder. That lets one plant serve road surfacing, and the same modified bitumen can also serve waterproofing (basements, underground works and roofs).

💰 What Should Buyers Check Before Choosing a PMB Plant for Sale and Comparing PMB Plant Price?

Search results for a PMB plant for sale will show a wide range of quotes. A lower headline number often leaves things out. The site does not publish prices, so ask for a written quotation. When you compare polymer modified bitumen plant price or PMB plant price offers, put them side by side on the same basis.

Buyer Checklist

Factors that move the price of an SBS bitumen plant:

1. Capacity tier (5–6, 8–10 or 15–20 t/h)
2. Manual or automatic control
3. Number of colloid mills and their power
4. Heat exchanger and thermal oil furnace size
5. Freight, installation and training

A reliable SBS modified bitumen plant manufacturer should be able to explain each of these in plain terms and show reference installations. Ask for project cases and, if possible, a factory visit or a video of a live run.

💬 Final thought: A cheap PMB plant with weak dosing costs more over time, through wasted polymer, rejected batches and unstable storage. Accurate feeding is the difference between a plant that produces consistent polymer modified bitumen and one that needs constant operator correction.

📩 Ready to Discuss Your PMB Project?

Whether you need a 10 TPH PMB plant or a 20 TPH polymer modified bitumen plant, the STOM/SINOTO engineering team can review your capacity target, polymer type and dosing requirements, and quote a configuration to match.

👉 Send Your Inquiry Now and Get a Free Quote for Your Polymer Modified Bitumen Plant

📧 info@stomglobal.com | 📱 WhatsApp: +86 190 5958 1045

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