Asphalt Pump

Asphalt, bitumen and pitch are often treated as synonyms but require distinct pump configurations. CAP (Cimento Asfáltico de Petróleo) is classified by ANP into four standard penetrations: 30/45, 50/70, 85/100 and 150/200 — refined, clean product with Newtonian behavior between 150 °C and 180 °C, served by standard FBE with steam jacket. Blown (oxidized) bitumen undergoes controlled oxidation that raises viscosity three to five times over the original CAP. It requires higher torque, slightly enlarged clearances, and above 1,500 cSt sustained, switching to FBEI internal gear is technically more efficient. Polymer-modified asphalt (AMP with SBS or EVA) requires low shear to avoid degrading the polymer chain — typical FBEI application. Coal-tar pitch is a distinct product: distillation residue, thixotropic, abrasive, softening point between 40 °C and 120 °C. Requires reinforced casing, enlarged clearances and strict cold-start procedures. Asphalt emulsion (CAE) has acidic pH between 2 and 4 and mandates AISI 316 stainless casing — the only asphalt application where stainless is technically necessary.

• CAP 30/45 at 180 °C ≈ 230 cSt — jacketed FBE, cast iron
• CAP 50/70 at 165 °C ≈ 320 cSt — jacketed FBE, carbon steel or cast iron
• CAP 85/100 at 150 °C ≈ 380 cSt — jacketed FBE, cast iron
• Blown bitumen 85/25 at 150 °C ≈ 2,500 cSt — FBEI preferred
• Coal-tar pitch at 120 °C ≈ 1,500 cSt — FBEI with reinforced casing
• Asphalt emulsion (CAE) — FBEI in AISI 316 stainless, mandatory
• SBS/AMP modified CAP — FBEI to preserve polymer

An asphalt pump without integrated heating fails sooner or later. Heat from product passing through the casing is not enough to keep the entire metal mass above the critical pumping temperature, especially at the mechanical seal, bearings and end covers, which lose heat to the environment more rapidly. The FBE CA (With Heating Chamber) variant solves this: the casing is cast with an integral jacket that circulates saturated steam at 6-10 bar (150-180 °C) or thermal oil up to 300 °C. Steam jacket is the classic standard for conventional asphalt plants with own steam generation. Heating is uniform, response is rapid and there are no cold spots — casing temperature tracks steam temperature with lag under 10 °C in regime. Thermal oil replaces steam when the plant already operates a thermal fluid loop (typical in refineries producing CAP and waterproofing factories), offering more stable temperature and no condensate. Electrical tracing is acceptable only for small pumps (DN50 or smaller) or auxiliary lines. On the main transfer pump it fails to deliver uniform heating on the lower casing and fails repeatedly on cold starts.

Every cold start is a slow-motion destructive test. Most asphalt pump failures in Brazilian plants do not happen in continuous regime but in start-up attempts without sufficient warm-up. Minimum practical temperature to start an FBE pump with CAP 50/70 is 130 °C measured at the pump casing — not the tank, not the line, not the jacket outlet. Below that, CAP 50/70 viscosity exceeds 1,500 cSt and start torque breaks keys, deforms gear teeth or trips the motor breaker. A 20 °C drop typically doubles CAP viscosity, doubling the torque required at the shaft. A motor sized to run CAP 50/70 at 165 °C (320 cSt) and actually running at 145 °C (where viscosity exceeds 550 cSt) enters mechanical overload and trips the thermal — one of the most common failure modes in poorly instrumented plants. The mature start-up procedure follows four steps: heat the jacket for 45 to 60 minutes before energizing the motor, confirming via local thermocouple on the casing that the specified minimum was reached; confirm the discharge valve is open (starting positive displacement against a closed valve is a guaranteed catastrophic failure); energize and run at minimum flow for 2 to 3 minutes before loading the system; monitor vibration and bearing temperature during the first 5 minutes.

A conventional asphalt plant has between six and ten distinct pumping points. Truck unloading to the storage tank operates at ~150 °C with viscosity ~600 cSt, served by jacketed FBE 2" or 3". Tank-to-mixer transfer (drum mix) is the most critical point for continuity and operates at ~165 °C with ~320 cSt viscosity for CAP 50/70. Tank recirculation for homogenization can use standard FBE at 160 °C. Burner feed (when the plant uses asphalt itself as tank heater fuel) typically operates at 140 °C with viscosity ~800 cSt — a point where small FBE at 500 rpm is adequate. SBS-modified CAP blending at 175 °C (~1,200 cSt) and asphalt emulsion transfer at 60 °C (~200 cSt) are the two points where FBEI in 316 stainless becomes technically mandatory. Truck loading at the plant exit uses a pump identical to the unloading one — jacketed FBE 2" or 3". The unblocking return loop (line used to maintain minimum circulation when production pauses) operates on standard FBE. Properly sizing each point against actual process temperature is the difference between a plant running 7,000 hours/year and one stopping for maintenance every 90 days.

FB Bombas has manufactured gear pumps for asphalt transfer since the 1950s, when the first plants in inland São Paulo and Paraná began operation. Today the FBE line is supplied in twelve standard sizes from 1/8" to 6", with steam or thermal-fluid jacket option, in cast iron, carbon steel or 316 stainless — factory specification, not field adaptation. Served plants include federal highway concessionaires, CBIC System paving companies and asphalt emulsion manufacturers across the national territory. FB is registered in Petrobras CRCC Family 6 (Rotating Equipment), enabling direct supply to CAP-producing refineries and Petrobras asphalt terminals. Replacement of imported pumps (Viking, Netzsch, Maag, Edral) is done with direct dimensional compatibility and typical 20-35 calendar-day lead time against 4-8 months from foreign competitors. Spare parts — gears, shafts, bushings, seals, jacket covers — are manufactured in Cabreúva, Brazil, with standard stock available. For plants in critical production regime, FB offers field application-engineer technical support via +55 11 4898-9200.