Agitating action feedback
While I agree that air agitation as described in “Agitating action” ( Simple Solutions , PE , May 2001, p 12) is a good, effective means of agitating the contents of storage vessels, there are two points that should be noted.
Do not use the plant compressed air system as the source of the air. The high pressure system (90 psi or greater) is the most expensive utility in the plant, based on energy and maintenance. In this application, it is also unregulated as to pressure and volume in most cases. Instead, order a high volume, low pressure blower and dedicate it to the tanks or sumps. This works very well as the head of liquid involved is usually very low (typically less than 30 ft of water or 14.5 psi).
The holes in the sparger should be located on the bottom half of the horizontal section at about 45 deg from vertical on both sides of the center of the bottom of the pipe. This position forces the air to push the fluid out of the section first and then starts the bubbling evenly across the length of the pipe. Information from the suppliers would confirm this design.
I enjoy your magazine and appreciate the ideas and articles. — Donald W. Erskine, Manager, Facilities Engineering, EnerSys Inc., Reading, PA
Pushing tape a different way
I have a comment on “Pushing tape through conduit.” ( Simple Solutions , PE , April 2001, p 8) Although air may work in this situation, it would be easier and safer to use a vacuum on one end. Using air to push the nut, you may hit something — like live energized parts of panels — or someone — like the helper waiting at the other end. To use the vacuum method, you use a sponge product, sometimes referred to as a “sponge pig,” or a newer product that looks like a parachute, or I have even used a small piece of plastic page and sucked it through the pipe. — Daniel Linton, Industrial Maintenance Coordinator/Instructor, Garden City Community College, Garden City, KS
Positive vendor relationship pays off
Thanks for a great Editorial regarding the handling of subcontractors and various other vendors (“Lessons from a neophyte,” PE , May 2001, p 10).
I feel that a great vendor will save you more money that you ever know. He also will make you look good because he performs his job with great aplomb and apparent ease. My hazardous waste broker is just that type of vendor. When he is here on-the-job, I can literally walk out and not worry in the slightest. It would take at least a 10% decrease in costs just to get me to consider another vendor. I do about $150,000/yr with the firm.
The vendors that I do not have that relationship with, drive me wild! They do not show up when they are supposed to, overbill, and almost always are unwilling to correct anything. — John Atkins, CPE, Webcraft, a Vertis Direct Marketing Service, North Brunswick, NJ
“HowStuffWorks” in the May issue (p 80) contained an error. The text stated, “When the switch on the electromagnet is open, it attracts the armature (blue).”The text should have stated, “When the switch on the electromagnet is closed, it attracts the armature (blue).”