Alfa Laval DuraCirc Circumferential Piston Pump

Alfa Laval DuraCirc circumferential piston pump: scope of the range

The Alfa Laval DuraCirc is a hygienic circumferential piston pump (CPP), a positive displacement design in which two wing-shaped rotors turn inside a rotorcase. It is aimed at dairy, food, beverage, confectionery and home and personal care processes, where the pump has to be cleanable, efficient at moving viscous product and simple to service. Seven Star LLC supplies the DuraCirc range in Oman and the GCC as an independent supplier in Muscat. The range has 13 models, so the right model is selected from your duty data rather than from a single ordering code.

DuraCirc technical specifications

Maximum values are limits for the range. A small model will not reach the top flow, and not every model reaches the top pressure, so confirm the model against the duty point.

How the DuraCirc pump works

Two rotors sit in a pumping chamber called the rotorcase, each on its own shaft held rigidly in the gearcase. Timing gears keep the rotors synchronised, and together with the shimming they make sure the rotors never touch each other or the casing. A geared electric motor usually supplies the drive.

The clearances inside the chamber are small. As the rotors unmesh at the inlet, a partial vacuum forms and the pressure drops locally, so liquid is pushed into the pump. The rotor wings then carry the fluid around the channel, and when the wings mesh again at the discharge the fluid is forced out. Tight clearances give high volumetric efficiency, meaning little product slips back and the flow is predictable even against pressure.

Design features that reduce risk in the DuraCirc

The port and pump-head geometry is shaped to give a very low NPSHr, which lowers the risk of cavitation and allows the pump to work in difficult suction conditions. Large-diameter shafts sit in a solid stainless gearcase on heavy-duty, long-life bearings; the manufacturer quotes tens of thousands of hours. The stiffness of this arrangement is what allows close clearances without pump-head contact.

The seal is modular. If the process changes, it can be converted without re-machining or adding flush housings. The optional Uni-Fit retrofit port is intended for direct replacement of existing circumferential piston pumps, from Alfa Laval and other makes, without altering the pipework.

Hygienic design: what the DuraCirc offers

• Certified to EHEDG and 3-A hygienic design standards.
• Profiled product-wetted elastomers that are FDA-compliant and have a defined compression, so there are no crevices or dead zones.
• Seal faces fully immersed in the product, which improves cleaning.
• All-stainless-steel construction suitable for hygienic washdown.
• Long-life FDA-compliant gearbox lubricant.

The manufacturer points out that the pump combines cleanability with high volumetric efficiency, which some other circumferential piston pumps do not.

Where the DuraCirc fits and related pumps

A DuraCirc is normally chosen when the product is viscous, shear sensitive or needs to be metered at pressure: yoghurt and cream, sauces, fruit preparations, chocolate and confectionery masses, creams and lotions. It overlaps with rotary lobe pumps, so the alternatives in the same hygienic family are the OptiLobe, SRU and SX rotary lobe pumps, and the Twin Screw pump when one pump must handle both process and CIP duty. The DuraCirc stands out in the higher pressure end, with the range going to 40 bar, whereas the lobe pumps listed in this family stop at 8, 15 and 20 bar respectively.

Selecting a DuraCirc pump: ordering checklist

• Product name, viscosity range and temperature, and whether it contains particles or fibres.
• Required flow and discharge pressure, and suction conditions for NPSH.
• Seal arrangement: single, flushed or double, and the flush or barrier medium.
• Elastomer type compatible with the product and the CIP chemicals.
• Port connection standard, and whether a Uni-Fit retrofit port is needed to match an existing line.
• Whether the pump replaces an existing unit, in which case send the nameplate details.
• Drive: bare shaft or complete unit, and the speed control method.

Installation, commissioning and maintenance

As with all positive displacement pumps, fit a pressure relief device on the discharge side and never run the pump against a closed valve. Check rotation direction before first start and fill the gearcase with the specified lubricant to the proper level. During commissioning, run the pump with a cleaning solution first so that the seal faces are wetted before any product is pumped.

The design aims to make routine jobs short. The single mechanical seal is front-loading and self-setting, so it can be replaced in place without removing the pump from the line. Shimming is external, outside the rotorcase, so the gearbox does not need to be opened to adjust clearance. Rotors and the rotorcase can be replaced quickly, and spare parts are fully interchangeable. Service kits exist for single, flushed and double seals, for O-rings, flush O-rings and for the gearbox elastomers. For spares planning, hold at least one seal kit and one O-ring kit for each installed model, and record the oil change interval of 3,000 hours.

Typical applications in Oman and the GCC

Dairies, drinks and juice plants, bakery and confectionery producers, and personal care manufacturers across the Gulf are the natural users of this pump type. Ambient temperatures are high and plants are washed down frequently, so the stainless casing, FDA-grade lubricant and easy in-place seal change are practical benefits. In new plants it is common to install a CPP for viscous or pressure-demanding duties, while the same site uses centrifugal pumps for water-like fluids.

Information to send with an RFQ

• {pn} model size if known, or the nameplate data of an existing pump.
• Product, viscosity and temperature data, including CIP temperature.
• Flow, differential pressure and suction conditions.
• Seal type and elastomer preference.
• Port connections, and whether the pump must replace another make.
• Certificates or documentation required, and destination site.

Documents and quotation

We do not host a datasheet for the DuraCirc on this page. Send us the model size or the nameplate data and we will confirm which official documents are available for it.

Seven Star LLC is an independent supplier in Muscat. We quote on the data you provide and reply with availability and lead time.