Might help to keep the housing filled with water during the offseason - if that is possible. Oil would work better - however this is drinking water.
I had a similar problem with a pool pump that only runs occasionally to power a fountian. The iron outlet pipe will oxidize to the point that it restricts flow.
Seems like continuis running pumps suffer less corrosion due to a lack of oxygen and wet/dry cycles.
In this case it is a matter of more expensive stainless steel, zinc, or aluminum housings, or perhaps plastics such as PVC or Nylon
Or the iron housing, with a constant battle against corrosion...
I didn't install the original pump so I assume the pipe was carbon steel. I know it wasn't stainless steel. The pump body was cast iron and we run polyethylene pipe down to the lake. We thoroughly drained the pipes and the pump at the end of the summer. Perhaps the pipe-joint compound used by the installer dried up and let water into the pipe-to-pump threads, which caused the rust over the years. --Jon
I have seen similar failures due to conditions we can't easily test for. Your sink drain provides a good example, although I'd think the manufacturer--knowing the use conditions--would have tested drains under different water conditions. Maybe a cheap knock-off manufacturer went for low cost instead of quality. --Jon
Was the pipe carbon steel or stainless steel? I wouldn't expect a galvanic couple between carbon steel and cast iron, but depending on the type of stainless, there could be a significant galvanic couple between stainless and cast iron. A plastic or rubber isolator between the two could help prevent this.
Jon, I understand the difference between vibration, temperature, and corrosion tests, and know there are standards for each.
Applying the results of a vibration and temperature tests are MUCH easier to deciding the life of a component than it is to using the corrosion results.
The specifications for a component will say "up to 50g, 155deg F". It may even say something about the 20% salt bath immersion for 20 days.
I saw a new sink fixture component corrode away in 5 years on city water when I was a kid. I think it would be difficult to relate the corrosion test results to city water to come up with an expected lifetime.
People would run special corrosion tests, which many commercial test labs know how to perform. The "shake-and-bake" tests look for structural weaknesses at various frequencies and g levels, while the environmental temperature tests look for premature electrical and electronic failures as well as failures induced by the stresses and strains created by heating and cooling. --Jon Titus
On a related subject, the US National Institute of Science and Technology (NIST) recently published information about the failures of carbon nanotubes used as electrical conductors in microcircuits. Tests showed failures of the nanotubes after only 40 hours. Although many researchers have touted the capabilities of these carbon structures to carry high currents, they seem to have problems that deserve more research before companies use them in integrated circuits. You can read the complete article at: http://www.nist.gov/public_affairs/tech-beat/tb20110816.cfm#cnt. --Jon Titus
Wouldn't it be difficult to determine the life of a component against corrosion in a "shake & bake" test? How would you accelerate corrosion and still get a meaningful result for component life-time?
Those types of tests should be part of a comprehensive testing program, but many small companies lack a strong background in testing or they lack the time and money to have a contract company run them. Also, when a company custom builds mechatronic equipment, they might not think such tests deserve attention for one-off designs. Also, I doubt many colleges or universities teach engineers about real-world product or system tests. --Jon
Sorry to hear about your pump, Jon. Aren't the so-called "shake and bake" tests a standard best practice for mechanical parts and assemblies or is that just another example of a no-brainer routine falling through the cracks due to engineering short cuts?
As energy efficiency becomes more and more a concern for makers of electronics devices, researchers are coming up with new ways to harvest energy from sound vibration, footsteps, and even electromagnetic fields in the air.
The government wants to study your brain, and DARPA wants to use similar information to give robots true autonomy beyond any artificial intelligence developed to date. Sound like science fiction? It's not.
From Dell / Intel® New Paradigms in Design Work Scott Hamilton, vertical market strategist for Dell Precision workstations, 5/2/2013 3
Early in my career, I worked as a draftsman and remember the days of drawing on vellum with numbered pencils and Mylar with plastic lead. This was a fun experience in the sense that I ...
I've been using workstations for more than 10 years and love finding ways to get more performance from my system. With demanding professional applications that require more power each ...
A lasting memory from my first job as an engineer in an auto assembly plant is standing on hard concrete at six in the morning, vending-machine coffee clutched in hand, listening to ...
A quick look into the merger of two powerhouse 3D printing OEMs and the new leader in rapid prototyping solutions, Stratasys. The industrial revolution is now led by 3D printing and engineers are given the opportunity to fully maximize their design capabilities, reduce their time-to-market and functionally test prototypes cheaper, faster and easier. Bruce Bradshaw, Director of Marketing in North America, will explore the large product offering and variety of materials that will help CAD designers articulate their product design with actual, physical prototypes. This broadcast will dive deep into technical information including application specific stories from real world customers and their experiences with 3D printing. 3D Printing is
To save this item to your list of favorite Design News content so you can find it later in your Profile page, click the "Save It" button next to the item.
If you found this interesting or useful, please use the links to the services below to share it with other readers. You will need a free account with each service to share an item via that service.
Tweet This
0 
