Handling coupling complications in sliding vane pumps

PSG partners with NORD to deliver alignment-free, positive displacement pumping solutions

Sometimes it takes but one good idea to change everything. This was the case when Tom Koren, the director of engineering at NORD Gear Corporation in Waunakee, Wis., approached a potential customer with a way to greatly improve one of its product lines. He and the NORD sales team had been calling on them for years with little success, but so effective was the idea that the company – Blackmer, Grand Rapids, Mich., a product brand of PSG, Oakbrook Terrace, Ill., a Dover company — is now a business partner, and has made plans to incorporate NORD’s concept into all of its Blackmer brand of pumps.

Joining Forces
The idea? Eliminate the one component that causes the greatest amount of grief in a typical pump drive application — the coupling.

“For the previous five or six years, I’d been thinking about developing a hollow socket shaft design for our inline speed reducers,” Koren said. “So when we heard Blackmer was looking at a redesign on one of its sliding vane pump families, it was an opportunity for us to present the no-coupling concept of directly interfacing their pump with our speed reducer. They agreed to test it, and here we are today as their main gearbox supplier.”

PSG product manager Geoff VanLeeuwen said there were several good reasons to adopt the hollow socket design. “Anytime you have two mating shafts, they must be kept in alignment – if not, you end up with additional load and possibly vibration that will reduce the life of that product,” he explained. “The problem with a traditional pump and motor arrangement is that a coupling is used to join them. Even a skilled technician needs a fair amount of time to get the different pieces shimmed, tweaked and aligned properly. The effort is required not only during the initial installation, but also whenever routine maintenance is performed.”

Solving Problems
The industry has been living with this aligned coupling challenge for as long as there’ve been electric pumps, VanLeeuwen noted. But as competition grows and skilled technicians become increasingly scarce, those responsible for plant operations often settle for a quick “eyeball it as best you can” approach to shaft alignment, accepting the fact that pump life will suffer as a result.

“Companies need to make money,” he said. “In a typical chemical plant or rail terminal, for example, you could be facing hundreds of dollars per hour of lost productivity if a pump goes down, and possibly far more than that. So they’ll do whatever it takes to get up and running quickly. The problem of poor maintenance has a snowball effect. Instead of spending a couple hours to properly align a pump, suddenly you have a day or two of unexpected downtime when the coupling fails or the pump seizes, just because someone was rushed. Our new GNX alignment-free pumps eliminate all that.”

Blackmer also made installation much easier. Because the new design is basically plug and play, the amount of integration work required by the customer facility has pretty much dropped to zero, VanLeeuwensaid. “So instead of 15 percent of our pumps being sold as turnkey solutions, that figure increased to 72 percent last year.”

Blackmer is just getting started. The first phase of their GNX- and GNXH-series rollout – now complete – focused on its 2- and 2.5-inch flange pumps. Using a NORD SK 771.1 gear unit directly coupled to a Blackmer heavy-duty, self-adjusting sliding vane pumps, the self-contained units offer maximum flow capacities of 86 gpm (325 L/min) and 155 gpm (587 L/min) respectively. Phases II and III (which VanLeeuwen expects will be completed over the next six months) will extend to the Blackmer larger frame 3- and 4-inch pumps, boasting up to 50 hp and 500 gpm (1,893 L/min).

Building on Success
NORD is also busy rolling out new products. NORD’s single-stage in-line helical gear unit line (used with the Blackmer GNX- and GNXH-series pumps) will be expanded with three larger products – the SK 871.1, SK 971.1 and SK 1071.1. Each is available with NORD’s exclusive hollow-socket option.

The NORD gear unit series is ideal for virtually any high-speed pumping, mixing or conveying application. Unlike the aluminum alloy construction of the smaller single-stage products, the three new gear units feature cast iron housings.

The NORD output torque ranges from 3,540 to 8,850 lb-in with gear ratios from 1.4:1 to 8.1:1 and a power range of 1.5 to 60 hp.  Mounted by a choice of foot-mount, IEC flange-mount (B5 or B14), foot/flange mount and NEMA standard output flange and shaft, the gear units provide the flexibility for customers to specify these drive solutions for countless applications. These units replace NORD’s SK 41E and SK 51E. Plus, they’re interchangeable with other European-designed gear units.

Koren explained these and other NORD gear reducers offer a long list of standard features, including a robust one-piece UNICASE? housing, Autovent pressure regulation, and high-strength, high-precision carburized gearing and high-capacity bearings.

For extreme shaft and bearing loads, customers have the option of upgrading to twin-tapered roller bearings and a higher-strength alloy steel shaft. Plus, for corrosive environments or where routine wash-downs are needed, NORD’s exclusive NSD TUPH aluminum alloy surface conversion solution was developed as a cost-effective alternative to stainless steel gearmotors. (NSD TUPH is available for NORD’s single stage gear units through size 771.1)

“What differentiates NORD from the competition are high-quality products, short lead times, and excellent customer support,” said Koren. “We’re probably not the least expensive supplier. But as illustrated in our relationship with Blackmer, our solutions are extremely innovative and we’re a good business partner.”

VanLeeuwen agreed, summarizing the relationship like this: “NORD was willing to dedicate time and resources to solve a specific problem faced by everyone in this industry.” He laughed. “The ironic part is we didn’t really invent anything. People have been using motors, gearboxes and pumps for decades. What makes our solution so effective is the way we paired them together. It’s been so successful that we’ve decided to gradually phase out all of our own gear units in favor of NORD’s. As proven leaders, Blackmer and NORD offer the new industry standard for pump unit assemblies. It eliminates unexpected downtime, and simplifies installation and maintenance tasks. Plus, installations benefit from noticeable improvements in uptime and ease-of-use. Welcome to the new normal of pump reliability.”