Twin Screw pumping technology has been around for over 100 years. It was developed in the oil & gas industry as means for pumping multiphase products. It wasn’t until the end of the 20th century that Jung Process Systems help to develop the very first sanitary, twin screw positive displacement pump that could pass both EHEDG and 3A certification. Since then Jung Process and Axiflow Technologies have developed a wide range of solutions for the most difficult pumping applications.
Comparison of Positive Displacement Pumping Technologies
Why Twin Screw Technology is Making all other PD Pump Technologies Obsolete!
Lobe-style and circumferential piston pumps are the primary pumping means in today’s sanitary industry. They provide a relatively low cost means of pumping basic ingredients from point A to point B.
So what do you use if your process requires something other than simple product transfer? Let’s say your process requires gentle product handling, low pulsation delivery, or high suction capability without the disadvantages of a progressive cavity pump?
The Axiflow Sanitary, Twin Screw, Positive Displacement Pump is changing the way companies look at their process pumps. Here are some basic comparisons:
Twin Screw Pumps
Twin screw technology is the ONLY type positive displacement pump that has the ability to run up to 4,000 RPMs. Unlike any other PD pump, the same pump can perform both process and CIP. Imagine being able to eliminate additional CIP return pumps, bypass valves and all of the excess controls. On viscous products, Twin Screw pumps can run at a relatively low speed to be gentle and provide a very high suction capability. On thin, water-like products, the Axiflow pump can be sped up to overcome the slip to maintain high velocities to perform CIP and CIP return pump functions. This ability to change from very thin to very thick liquids with the same pump is a great way to reduce the number of pumps in any one plant.
As rotary lobe (RL) and circumferential piston (CP) pumps wear, the pump’s suction capability is greatly reduced, and the only way to achieve the same output is to increase speed. But speed increase is very limited. With the widest range of speeds, Twin Screw pumps are able to be sped up to overcome slip. This increase in speed does not diminish its ability to pull a good vacuum. Therefore, you get much more useful life out of a set of screws than you would out of a set of rotor.
Much like progressive cavity (PC) pumps, Twin Screw pumps have the same high suction capability, both are lower shear pumping devices, both are capable of handling large soft solids and both provide a smooth, virtually pulse free delivery of product. Where Twin Screw sets itself apart is in its ability to run dry for hours. In fact, Twin Screw pumps can pump up to 60% air and it will never air-lock. And unlike rotary lobe pumps, it will run as quiet as a mouse when running dry. The symmetrical screws do not require product to stabilize the rotor. This means there is no overhung load to cause contact between the rotor and the housing.
Twin Screw pumps also are incredibly versatile. By simply switching to a different screw pitch, you can change the entire flow curve on the pump. For instance, a tighter screw pitch is capable of higher pressures but lower flowrates. A larger screw pitch enables a pump to perform higher flowrates at lower pressures and much lower shear rates, while pumping larger soft solids.
Axiflow is the most successful Sanitary Twin Screw PD pump in North America. It sets itself apart from other twin screw pump offerings by providing a wet end and gearcase/bearing housing that is completely machined out of 316L billet stainless steel, straight through the entire bearing housing without being removed from the five axis machine. This ensures the most precise tolerances and the ability for the entire pump and bearing housing to expand and contract together at the most extreme of temperatures.
With high suction capability, the ability to run dry for hours, low shear pumping capability, delicate handling of soft solids up to 1-5/8” and the ability to deliver a smooth, non-pulsing, repeatable product flow, the Axiflow Pump is capable of pumping the widest range of product viscosities (1 to 1,000,000 cps), operating at the widest range of pump speeds (up to 4,000 RPMs), and operating at the widest range of product temperatures (up to 425°F) of any other PD pump (twin screw or otherwise) on the market! These capabilities greatly reduce the wear on the pump and cost/need of spare parts. This is why Axiflow pumps are proving to be the Lowest Total Cost of Ownership (TCO) for PD pumps.