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Making a Better Circulator


When you consider product research and development, there is a tendency to focus on sophistication. In some cases this might be effective digital controls or aggressively engineered combustion solutions that dramatically increased efficiency. But sometimes, relatively simple engineering solutions can provide dramatic results.


One example of this was obvious at the NAOHSM Trade Show (now OESP), held at Hershey Lodge, Hershey PA, May 22-26, 2011 where Wilo USA, LLC was showcasing a new volute with a reengineered flange/volute solution for its Stratos ECO high-efficiency residential circulators. The high-efficiency part of the system, up to 80 percent energy savings, falls into the area noted earlier of sexy research and development. However, the new flange solution provided a dramatic increase in efficiency itself, where inventory management is concerned. The Stratos ECO had already made inroads in that area with its ability to dial in a range of capacity with Wilo noting that the previous version could potentially replaced 12 competitive pump options. The new flange (and check valve) solution allowed the company to up that claim to 34.


Basically, the rotating flange is a spinner flange that locks in at 90° points, allowing it to replace a two bolt flange where the bolt plane is either parallel to the pump shaft or perpendicular to the pump shaft.


‘The technology itself is relatively simple and we found the industry reaction overwhelming when we first came out with this new product at NAOHSM,” said Steve Thompson, vice president of Rosemont, Il-based Wilo USA in charge of the building services market segment products. ‘I think it really did catch everybody by surprise. People were looking at us for electronic solutions or more high efficiency pumps and we came up with a very simple, easy and very effective mechanical solution so was probably one of the more fun launches I’ve been a part of.”


The concept was originally developed nearly four years ago. As Thompson describes it, it was one of those things where a bunch of the pump guys were sitting around the table at lunch talking about things that could be done with the pump to make the whole ‘horror show” of two different pumps types easier. ‘We discussed perhaps using a union connection like they have over in Europe, but that probably wouldn’t fly here in the states,” he said. ‘And we talked about a flange and may be doing a four-bolt, but the problem is that if you run into issues where a pump is installed very close to a wall and there is not enough clearance and it is heavier and stuff like that. So we developed the first concept (with the rotating flange) and we’ve been working on it probably two years now.”


The development process was actually highly involved for what might seem to be a relatively simple piece of engineering. There was substantial retooling involved in making the move and the volute had to be redeveloped from the ground up. This process started with a computer drafted image of the volute and then a plastic version that was formed with lasers. The plastic component then received a range of hydraulic tests and once those tests were passed it is sent down to the casting department. The metal cast prototype then received additional tests.


Two preliminary prototypes went through this process on the way to the final design. Along the way, the various prototypes were distributed to the company’s distributor focus group where reps and installers worked with the different versions and provided feedback. As a result of this feedback Wilo came up with a third and final version that was placed into production.


Thompson noted that, interestingly, the new development actually increase the hydraulic performance by about 5 percent to 10 percent compared to the old Eco simply as a byproduct of the new development.


Wilo also took the opportunity to look at the check valve part of the solution.


‘We really went the whole 9 yards, not just on the rotating flange feature but on the check valve as well,” said Thompson. ‘We include the check valve in the package that the pump comes with, but we do not install it in the volute because in some applications the check valve is not required such as a retrofit job,” said Thompson. ‘We also went with a black high temperature check valve rated for 250°F whereas most other manufacturers are using a white check valve rated to 205°F. All that adds up, with the eco-and the variable speed drive smart pump technology we can replace 34 of the competitors pump models with one of the Eco. So the contractor does not have to worry about what kind of pump P or she has on the truck, the wholesale distributors love it because they’re inventory management has made much simpler and from our standpoint we are not in the business of keeping inventory on our shelves for five or 10 years so it makes our inventory management easier is as well.”


So far, the flange solution is limited to the company’s higher tier ECO series. The reason comes down to economics. The eco-technology pumps are more expensive than a standard pocket circulator or a more base-level single or three-speed pump, and in that market segment the added cost is easier to absorb and the benefit becomes a true value add to both the distributor and the installer. ‘If the cost of the pump is higher and our margin percentages is still the same, but we have more margin dollars in the equation, it is easier for us to add this benefit and not substantially increased the price of the pump,” said Thompson. ‘With the more commodity pumps, you get into the same issues the residential water heater guys face where there is very little margin in it and you have a bunch of manufacturers battling for that high-volume space. That makes it difficult to throw in this extra, really good feature. But we don’t have a lot of extra room in there to increase the value of the product.”


Thompson noted that the reaction since launch has been very strong. ‘Once we came out with a lot of people, contractors especially, looked at it and said why didn’t somebody come out with this before?”

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