Twin Screw Pumps- What Are they and When Should You Use Them

upamfva · Anmeldungsdatum: 12.04.2022 Beiträge: 388

Twin Screw Pumps- What Are they and When Should You Use Them?

While many know SPXFlow/Waukesha Cherry Burrell for their industry leading line of external circumferential piston (ECP) Universal series pumps, did you know they also have another category leader with their Universal Twin Screw or UTS pump? In today’s post, we’re going to do an overview of Twin Screw pump technology and talk about a few applications we love them in and also some reasons you may want to stick with your existing ECP.To get more news about MONO pump Accessories, you can visit hw-screwpump.com official website.

Twin Screw Pumps- What are they?
First, let’s talk a little bit about Twin Screw pumps specifically for sanitary applications. About 10 years ago, Twin Screw pumps burst onto the scene in a big way in the sanitary space. Twin screw pumps, like traditional ECP or lobe pumps, are positive displacement type pumps. They give you a constant flow per revolution regardless of discharge pressure.
Twin screw pumps, as the name would imply, use a set of meshed screws to create sets of sealed cavities that moves the fluid being pumped along an axial path. The sealed cavities create a positive pressure that moves fluid from the pump inlet to the outlet in a smooth, consistent manner.

This creates gentle product handling and the ability to pump shear sensitive fluids with larger particulates in lower pressure applications. The axial flow path also allows us to handle higher discharge pressures than we typically can with an ECP pump.
Waukesha UTS screws are available in 3 different profiles including wide, medium, and narrow pitches to provide a wide range of pressure and flow capacities depending on application and product size. Wider pitch screws are used for lower pressure, higher flow applications, while narrow pitch rotors leverage their larger helical surface for high pressure, lower flow rate applications of where we need maximum suction at the pump inlet.

When should you use a Twin Screw Pump?

As we alluded to above, there are three applications we absolutely love to use the UTS in.

Because of the range of screw pitches available, pumping fluids with large solids is a great twin screw application. The wide pitches allow for whole solids handling that greatly reduces the damage we see in comparable products when running an ECP pump (even with single wing rotors). Think about applications like Greek Yogurts with whole fruits and apple pie filling.

We also love twin screw pumps for high pressure, low suction applications. We once supplied a customer who had been using a competitors ECP pump on his evaporator with a UTS and it was one of the few times anyone has ever thanked us for selling them a $30,000 pump assembly. Twin screw pumps are great for low suction applications like evaporators because of the sealed cavities the screws create. And the axial flow path (as opposed to the overhung radial motion of a ECP rotor on a shaft) also allows us to handle pressures up to 375 PSI!

Finally, and probably the best application, for a twin screw pump is dual-duty applications where we need to run both product and CIP. Because of the axial flow direction we talked about above, we’re able to run twin screw pumps at much higher speeds than we can run an ECP pump. While we can typically run ECPs up to about 500 RPM, with a twin screw, we can go all the way to 3500 RPM! This allows us to create the large amounts of turndown needed to run product at slower product flow rates and also create the 5-7 fps needed for turbulent flow during CIP, eliminating auxiliary CIP pumps and valving, greatly simplifying installation.