CR series heated-jacket gear pumps

Why a heated-jacket gear pump

Bitumen, pitch, hot-melt, waxes and many resins flow only when hot. The pump is the most exposed point of the line: a compact cast iron body with a shaft passing through it, which loses heat fast and, during a stop, becomes the first place where the product sets. Once the fluid has crystallised between the teeth, the motor cannot restart the pump.

The CR jacket solves this at the source. It wraps the whole pumping chamber, not just the flanges, so there is no cold spot where the product can solidify. The heating medium, thermal oil in most bitumen plants, steam or superheated water elsewhere, keeps the pump at the same temperature as the fluid. Underneath, the CR is a self-priming external gear pump: constant flow proportional to speed, no pulsation and a flow that does not depend on the pressure downstream.

CR series models and flow rates

Ten sizes cover transfer and dosing duties. Flow is given at 950 rpm; at other speeds it is proportional, and with an inverter the same pump is used for dosing.

Two operating modes: transfer at high flow, and dosing with an inverter on the motor. All models have a cast iron body and a jacket that wraps the whole pumping chamber.

Heating options: jacket, cartridges and hot spot

The standard CR jacket is connected to the plant thermal loop, with thermal oil, steam or superheated water. Where no central heater exists, or the pump is far from it, two alternatives are available:

• Electric cartridges: two to four cartridges inserted in the pump body, a probe, a solid-state relay and an electronic temperature controller. Up to temperature in about two minutes, on-off control in fractions of a second, heat produced where it is needed. Suited to bituminous mixes, cocoa mass and chocolate, plants without a thermal station and retrofits.
• Self-contained hot spot: the CR jacket is filled with thermal oil heated locally by up to three 300 W electric elements, 900 W in total, circulated by an 8 ZV auxiliary pump with a 6-pole motor, with precision thermostat and expansion tank. No boiler, no permits, no boiler maintenance; even, diffuse heating; a few hours of preheating; insulation of the pump is mandatory.

SEF version for filled bitumen and abrasive fluids

Modern road bitumen often carries a high percentage of filler, which makes it strongly abrasive: in a standard pump bearings and teeth wear quickly. The SEF version of the CR series answers with three design choices:

• support bearings housed outside the pump body, not in contact with the fluid;
• external timing gears running in an oil bath, so the internal teeth do not slide against each other;
• four gland packings, inexpensive and replaceable on site.

Protection is entrusted to an electronic torque limiter, a wattmetric relay on motor consumption; modified-geometry gears are optional for solid granules in suspension. Surface-hardening heat treatments are applied to the materials in contact with abrasive fluids. The SEF is the pump we recommend for filled bitumen plants and for any product carrying mineral loads.

Applications and how to request a CR pump

The CR series is used for bitumen transfer, recirculation and dosing in asphalt and membrane plants; for pitch and bituminous compounds; for hot-melt, polyurethane glue and synthetic adhesives; for waxes and paraffin; for heated molasses, fats and chocolate in cast iron executions; and alongside the SB series on bitumen distributors.

To size the pump we need the fluid, its working temperature, the flow in l/min or m³/h, the discharge pressure, the heating medium available and, for bitumen, the filler percentage. Write on WhatsApp or use the quote form: our Bologna factory, building self-priming external gear pumps since 1955, replies with the model, the drive and the heating system that fit your plant.