The following article was written by Franz Graf and originally appeared in the June 2012 issue of fluid magazine.
The family-owned Universal Hydraulik is a well-known company associated with heat exchangers. Until now, very little has been known about their expertise in building test stands. All this is about to change.
Let’s be honest. Would you be confident that a company that has primarily specialized in heat exchangers could build test stands? Internormen Technology, a company based in Altlussheim that has been part of the US industrial group Eaton for well over a year now, has no such concerns. On the contrary, Research and Development Manager Lothar Nagel is positively gushing: “We have been using the test stand in our production since 2005 and we need to be able to rely on a quick solution for any problem that may occur. And we have never been let down.”
The company that undertakes the development and production of heat exchangers, cooling filter systems, test stands, and much more besides, is not called Universal Hydraulik for nothing and has its head office in Neu-Anspach. However, it is important to remember that the Hessen-based company has been building test stands for the entire industry for a good 25 years. The management in Altlussheim and Lothar Nagel therefore had a very good idea of what they were letting themselves in for when the job was placed.
It all started at Internormen Technology because they were finding it difficult to cope with testing filters in the way they had been due to an ever growing product range and increased production volumes. Lothar Nagel remembers: “We had reached the limit of our capacity and therefore decided to go for a new test stand for hydraulic and lubricating oil filter, which we commissioned in 2005. We thus test all filter housings for tightness before we deliver them to the customers.”
Thesis as a basis for the performance specifications
What sounds so simple to start with is actually extremely complex. Let us look at a few facts and figures. Testing is done at 1.5 times the normal nominal pressure. The filter range covers operating pressures from 10 bar to 420 bar, in certain instances even up to 600 bar. The volumetric flow rates range from 30 l/min right up to several thousand liters per minute. These key figures alone are an indicator of just how difficult the task of building the new test stand was.
Nagel responded to the question of how the problem of testing filters had previously been resolved as follows: “Even before 2005 we used to work with a test stand, but a lot of manual work was involved. This test stand could perform no more than a third of the functions of the current system. This explains the vast amount of intervention required. We therefore had to automate the system, but with a high degree of flexibility in view of our extensive and diverse range of filters.”
The following procedure led to Universal Hydraulik being chosen by the filter specialists in Altlussheim to supply their test stand: “We set up a completely normal tendering process. Universal Hydraulik was ultimately awarded the job because they could offer the best price/performance ratio,” stresses Nagel, adding: “There were other companies who would have been technically capable of completing the project. The factor that swung the decision in favor of Universal Hydraulik was the fact that they were prepared to produce the test stand exactly as we wanted it.”
What might initially seem straightforward within the context of a customer/supplier relationship was not at all straightforward in this case. The R&D Manager of “Eaton’s Internormen Technology” explains: “It was comparatively difficult to define the brief so that we get a quotation for what we actually want. The preparatory work for building a test stand is significantly more complex than it is for a hydraulic cylinder, for example.”
The filter manufacturer chose a not altogether conventional route to fulfilling all the key specifications: a thesis was to point the way. Nagel again: “In the course of the thesis written in collaboration with HTW Dresden, we started by collating and evaluating all the requirements for the test stand. The first priority was the safety issues and then of course the purely technical specifications. At this point we didn’t even know what the test stand would look like. This thesis eventually formed the basis for the performance specifications to be produced. These specified many of the details of the test stand, but not the external appearance of the design. Finally, we used these requirements specifications as a basis for collecting the relevant quotations within the framework of an invitation to tender.”
High safety and ease of operation
While it has not been an issue thus far, cost naturally plays an important role in a major project of this kind. Lothar Nagel explains: “This kind of thesis offers enormous scope for maneuver, of course, and we could certainly have come in at the very high end in terms of cost. After the thesis had been submitted, a certain amount of tweaking was required in order to meet the budget set down by the management.” Apropos the budget, Nagel would not be drawn on an exact price for the test stand and gave a loose figure of several hundred thousand euros.
Universal Hydraulik thus set to work on the basis of the specifications given by Internormen Technology. The brief set down alone is indicative of the high degree of expertise required for this project. Karl Helmut Müller, Technical Manager for Plant Engineering, explained the approach adopted: “The external dimensions were derived from the filter geometries, filter throughput and a few other criteria. Specifically: cabin width 2.20 meters, depth 2 meters, height 2 meters, weight just under 12 tons.”
At this point we will confine ourselves to the following details: The tightness test stand primarily consists of a hydraulic unit, an electronic control unit and three test cabins. These walk-in cabins are classified according to test pressures: cabin 1 up to 630 bar, cabin 2 up to 300 bar and cabin 3 up to 100 bar. The parameters of the test piece are read in via a barcode and archived on completion of the test. A touch screen display is used as the man-machine interface. Control is performed via a soft SPC system with the corresponding visualization. For this test stand, the focus was placed on clear, easy operation and a high level of safety.
Universal Hydraulik and Eaton
Universal Hydraulik employs approximately 60 employees at its headquarters in Neu-Anspach. In addition to this there is a production site in Putim in the Czech Republic. This family business specializes in the design and manufacture of heat exchangers and cooling systems for fluids of all kinds. The company is also a systems supplier for hydraulic systems including pneumatics, lubrication, cooling, and electric control technology. Further information is available at www.universalhydraulik.de.
The roots of what is now Internormen Technology GmbH go back to 1972, when Helmut Franger founded Internormen Filter GmbH. The company has been part of the Eaton industrial group for well over a year. The product range of “Eaton’s Internormen Product Line” now extends far beyond the manufacture and sale of hydraulic and lubricating oil filters. This is supported by several areas of the company, including Contamination Monitoring, for example. Further details can be found at www.eaton.com/filtration or www.internormen.com.
Forward-looking strategy bearing fruit
As regards operation, there is one other important aspect to all this according to Lothar Nagel: “The test stand is not used in isolation in an ivory tower – it is working right in the midst of production. It therefore follows that this system is not operated by a specialist, but is often used by several people during a single shift and everyone must be able to handle the software. This fact posed a major challenge for the test stand designer.”
Even if the name Universal Hydraulik is largely associated with heat exchangers, the consideration that the company has already been producing customized test stands for 25 years is not unimportant to Managing Director Michael A. Uhl. Here is just a small selection of solutions already implemented: burst pressure test stands, analytical test stands for mechatronic systems, tire load test stands, differential pressure test stands and much more besides. This is what Uhl had to say: “The tightness test stand at Eaton in Altlussheim is a clear testament to our expertise. We have gathered expertise in this sector over a number of years, and because this is the case we will be pushing forward in this area and investing heavily in it in future. However, I admit that we are not as well known in this field as I would like. But we are working on that!”
That this forward-thinking strategy is already bearing fruit is borne out by the fact that another test stand is already in operation at another site of the Eaton Corporation. Lothar Nagel confirmed that “We have also put out an invitation to tender for the second test stand. Placing this contract was therefore not a foregone conclusion, notwithstanding the completely positive experience with the first test stand from Universal Hydraulik.” Michael A. Uhl also added: “As usual, the test stand will be accepted and dismantled on our premises and re-commissioned on the customer’s premises.”
With such complex and difficult designs, the question of the construction time inevitably arises. Karl Helmut Müller’s answer to this question is as follows: “In general, this takes around 12 o 16 weeks. It must not be forgotten that these are customized solutions. Or to put it another way, our test stands are not simply taken from the shelf.”
There are several reasons why the boss of Universal Hydraulic will be placing greater emphasis on building test stands in future. Uhl: “Particularly just recently, we have frequently received positive feedback from our customer. There are reasons for this: We are able to maintain a strong price/performance ratio, offer high quality and are also known for devising extremely customized solutions. This has of course given us an enormous incentive to continue expanding this area.” In view of this, it makes absolute sense for fluid to come back and take stock before too long.