Would you buy a used car from these folks?
There's been a lot of talk since the story about the defective MWI pumps broke on March 12. And while the media and the Corps have covered various aspects of the story around the pumps, no one has publicly looked at the system itself to figure out exactly what problems may still need to be addressed. Fortunately, nearly everything about the system is fully on display for anyone to walk up to and examine.
Over the next few posts, I'm going to be concentrating on specific deficiencies in the design of the pumping system. Some relate to fabrication, some relate to engineering design, and some relate to installation. This is nitty-gritty stuff that engineers love (or should love) to dig into. Keep in mind that engineering is not a static field - it is subject to opinion on how to do things the best way. These are my opinions, backed up with my experience as a mechanical engineer and consultations with others familiar with similar installations. Some of this may seem a bit didactic, but I'll always show that there's a point.
I'm going to start with the pump units themselves. As a refresher, you may wish to read my earlier post about the fundamentals of how the pumps and their drive units are set up.
Out at the Orleans canal floodgates, all ten pumps have been pulled in anticipation of refits by MWI. The five west pumps were pulled Wednesday, March 22. The five east pumps have been on the deck since last October. They're all up on the deck on the east (Marconi Drive) side, and anyone can go up and check them out. So I did so last Sunday. So did at least five other people while I was there, including two joggers with their dogs.
Frankly, the workmanship is ... not great. Let me lead off by showing you something that I had to laugh at to keep from crying:
Yes, that's duct tape wrapped around a hose meant to hold at least 1000 psi of hydraulic oil (I think - I'm not sure of the pressure on the outlet of the coolers). To top it all off, that particular fitting sits below the waterline when the pump is in the canal. Are they kidding us with this?
Allow me to further explain what you're looking at in that picture. The black piece is the fitting between the hydraulic hose coming out of the discharge of the Rineer hydraulic motor and the inlet of one of the two hydraulic coolers. The hose comes down from the top of the frame, and the duct tape is around the very section where the hose joins the fitting. I couldn't believe what I was seeing when I snapped this picture.
Let's step back a bit. Here's a picture of three of the five west pumps (the ones that were just pulled out of the canal last week):
I've noted the location of the typical waterline, which is based on the growth of those little barnicle things all over the pumps. As you can see, the fittings joining the hoses to the hydraulic cooler inlets on these pumps have all rusted. Here's a close-up of another cooler fitting from a west pump:
What is more surprising is that the fittings on the discharges of the coolers - which for most of the last year have been above the waterline, and thus only exposed to air and humidity - have also rusted. How could this happen? These pumps have only been in the canal since last June.
It's pretty simple. It appears that the manufacturer, MWI, skimped on the purchase of those fittings, buying carbon steel instead of stainless steel despite knowing they would be exposed to water all the time. Curiously, the Corps' specifications are oddly silent on the material of the hose fittings:
Considering the criticality of the installation (protection of life and property), use of stainless steel fittings in this application to prevent corrosion should have been a no-brainer.
You may be asking, why is the fitting in the duct tape photo not rusted? I believe that fitting is on one of the pumps which has been out of the canal since October (the ones from the east side of the project), so it was only in the water for a little over four months. The pumps shown in the other photos have been in the water for approximately ten months. This is troubling, since the expected service life of these pumps is about four years - the Corps has promised permanent pump stations at the lakefront by the end of 2010.
There is another possibility why the fittings on the east pumps don't show rust: they leak so much hydraulic oil that rust cannot form. There is some evidence for this. Below is a picture of one of the east pumps (which has been on the deck since October). I've highlighted the fitting on the discharge of the cooler.
Here's the highlighted area blown up:
I've noted the places where oil has apparently leaked.
This is not good manufacturing. Material selection is a pretty easy part of the engineering on this job, and it appears the ball was dropped. It certainly brings into question the quality of the work elsewhere on the job.
This part of the story may have a happy ending. As part of the refits the Corps and MWI are undertaking - apparently at the shop of Associated Pump & Supply in Houma, LA - all of the below-the-waterline connections which previously were between hose and pipe have been replaced with hard pipe, whioch hopefully won't leak. Now all the pumps have pieces of pipe sticking up out their sides, terminating with connection points which will be above the deck on the support platforms. Frankly, this should have been done in the first place by MWI, and if they knew there were going to be connections which remained underwater constantly (which they did, since the pumps are designed to be immersed in the canal), those fittings should have been corrosion-proof. That means using stainless steel, which is the industry standard. Keep in mind that none of this has ever been acknowledged as a problem by the Corps.
In future entries, I'll be looking at other problems with the pumping system. There are many, and none of them have been acknowledged by the Corps.
Over the next few posts, I'm going to be concentrating on specific deficiencies in the design of the pumping system. Some relate to fabrication, some relate to engineering design, and some relate to installation. This is nitty-gritty stuff that engineers love (or should love) to dig into. Keep in mind that engineering is not a static field - it is subject to opinion on how to do things the best way. These are my opinions, backed up with my experience as a mechanical engineer and consultations with others familiar with similar installations. Some of this may seem a bit didactic, but I'll always show that there's a point.
I'm going to start with the pump units themselves. As a refresher, you may wish to read my earlier post about the fundamentals of how the pumps and their drive units are set up.
Out at the Orleans canal floodgates, all ten pumps have been pulled in anticipation of refits by MWI. The five west pumps were pulled Wednesday, March 22. The five east pumps have been on the deck since last October. They're all up on the deck on the east (Marconi Drive) side, and anyone can go up and check them out. So I did so last Sunday. So did at least five other people while I was there, including two joggers with their dogs.
Frankly, the workmanship is ... not great. Let me lead off by showing you something that I had to laugh at to keep from crying:
Yes, that's duct tape wrapped around a hose meant to hold at least 1000 psi of hydraulic oil (I think - I'm not sure of the pressure on the outlet of the coolers). To top it all off, that particular fitting sits below the waterline when the pump is in the canal. Are they kidding us with this?
Allow me to further explain what you're looking at in that picture. The black piece is the fitting between the hydraulic hose coming out of the discharge of the Rineer hydraulic motor and the inlet of one of the two hydraulic coolers. The hose comes down from the top of the frame, and the duct tape is around the very section where the hose joins the fitting. I couldn't believe what I was seeing when I snapped this picture.
Let's step back a bit. Here's a picture of three of the five west pumps (the ones that were just pulled out of the canal last week):
I've noted the location of the typical waterline, which is based on the growth of those little barnicle things all over the pumps. As you can see, the fittings joining the hoses to the hydraulic cooler inlets on these pumps have all rusted. Here's a close-up of another cooler fitting from a west pump:
What is more surprising is that the fittings on the discharges of the coolers - which for most of the last year have been above the waterline, and thus only exposed to air and humidity - have also rusted. How could this happen? These pumps have only been in the canal since last June.
It's pretty simple. It appears that the manufacturer, MWI, skimped on the purchase of those fittings, buying carbon steel instead of stainless steel despite knowing they would be exposed to water all the time. Curiously, the Corps' specifications are oddly silent on the material of the hose fittings:
"2.4 Hydraulic Piping and Hose: ... All reinforced supply hose shall be double wire braid reinforcement and shall have minimum safe working pressure of 3,000 psi. All pipe fittings shall be socket weld type (with socket weld to thread fittings at conversion point of pipe to reinforced hose)..."
Considering the criticality of the installation (protection of life and property), use of stainless steel fittings in this application to prevent corrosion should have been a no-brainer.
You may be asking, why is the fitting in the duct tape photo not rusted? I believe that fitting is on one of the pumps which has been out of the canal since October (the ones from the east side of the project), so it was only in the water for a little over four months. The pumps shown in the other photos have been in the water for approximately ten months. This is troubling, since the expected service life of these pumps is about four years - the Corps has promised permanent pump stations at the lakefront by the end of 2010.
There is another possibility why the fittings on the east pumps don't show rust: they leak so much hydraulic oil that rust cannot form. There is some evidence for this. Below is a picture of one of the east pumps (which has been on the deck since October). I've highlighted the fitting on the discharge of the cooler.
Here's the highlighted area blown up:
I've noted the places where oil has apparently leaked.
This is not good manufacturing. Material selection is a pretty easy part of the engineering on this job, and it appears the ball was dropped. It certainly brings into question the quality of the work elsewhere on the job.
This part of the story may have a happy ending. As part of the refits the Corps and MWI are undertaking - apparently at the shop of Associated Pump & Supply in Houma, LA - all of the below-the-waterline connections which previously were between hose and pipe have been replaced with hard pipe, whioch hopefully won't leak. Now all the pumps have pieces of pipe sticking up out their sides, terminating with connection points which will be above the deck on the support platforms. Frankly, this should have been done in the first place by MWI, and if they knew there were going to be connections which remained underwater constantly (which they did, since the pumps are designed to be immersed in the canal), those fittings should have been corrosion-proof. That means using stainless steel, which is the industry standard. Keep in mind that none of this has ever been acknowledged as a problem by the Corps.
In future entries, I'll be looking at other problems with the pumping system. There are many, and none of them have been acknowledged by the Corps.
posted by mcbrid35 at
7:17 AM
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