Diaphragm Pumps Wearing Fast
Diaphragm Pumps Wearing Fast
(OP)
I am an elcetrical guy so bear with me. We are a steel foundry that uses a Corewash paint made by Ashland Chemical Corp. The paint is Velaplast ZWTXB 8090 Coating. We are using a double diaphragm pump to transfer this liquid paint into a corewash station which has jets to spray and coat our cores.I have been told that this paint has abrasives in it, and we are experiencing short life out of our pumps.The pumps quit pumping about once a week. The diaprhagm pumps have two balls and seats for cycling, these are beaking down fast. Are there any suggestions on another type of pump to transfer the liquid, or what do other companies use for corewash? Oh, I forgot to mention the prime mover of the pump is compressed air.





RE: Diaphragm Pumps Wearing Fast
SS housing (liquid side), all plastic,alu,...
also the valves (the 4 balls): SS,plastic,...
you might want to try a SS pump with SS balls.
RE: Diaphragm Pumps Wearing Fast
Have attached a paper in which using an inlet stabilizer the pump life has increased from three weeks to one year.
RE: Diaphragm Pumps Wearing Fast
Hose (peristaltic) pumps are another option.
RE: Diaphragm Pumps Wearing Fast
We do have the better pump with replaceable seats. As I said before the paint we use has an abrasive quality to it. I have just found out two important facts: We have switched to a new paint, and we are buying our pumps and rebuild kits from Grainger. The signifigance of where we are buying our parts is that we are probably not using the appropriate internal pump materials for this process. The balls and seats are worn in about three days, when we used to get a month out of our pumps. I just found out that we used to get our pumps from someone else who had proprietary components inside to handle this process. The people who build the pump for our application won't disclose what the balls and seats are made of. I appreciate everyone's input, hope everyone has a wonderful holiday!
RE: Diaphragm Pumps Wearing Fast
RTFE (Reinforced PTFE) is filled with fiber glass filler to improve strength and resistance to abrasive wear. Not to be used in applications that attack glass, such as hydrofluoric acid and hot strong caustics.
Stainless Filled PTFE. It Offers excellent abrasion resistance with higher pressure and temperature ratings than RTFE.
PEEK (PolyEtherEtherKetone). Excellent choice for high pressure, high temperature service and excellent abrasion and corrosion resistance.
RE: Diaphragm Pumps Wearing Fast
We used Graco diaphram pumps for the large volume filling. They had the most experience with abrasive issues at the time. The White Dioxide paint had "Zeospheres" in it, and was horribly abrasive. However, the pumps held up very well. Usually it was only the check valves that had to be replaced periodically.
We used positive displacement pumps for the tinting machines. (The abrasive is in the tint) Hardened shafts with mechanical seals for larger pumps (3 gpm) and hardened shafts with three sets of Teflon lip seals for the smaller pumps.
None of these lasted forever, it was said that we were in the pump repair business instead of the paint dispensing business.
If you want to discuss the issue, feel free to EMail me. I can tell you what I remember, and maybe even give you a company to talk to.
Charlie
www.facsco.com
RE: Diaphragm Pumps Wearing Fast
RE: Diaphragm Pumps Wearing Fast
That is unacceptable and ridiculous as you are the purchaser and user. I would look elsewhere for a new supplier whoi is more forthcoming and helpful. There are a lot of hungry people out there now.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Diaphragm Pumps Wearing Fast
I think there is an issue that has not been considered yet. Most of the answers so far refer to the materials of ball and seats. But do the balls and/or seats wear out or are they chemically attacked? If they are chemically attacked,a change of materials will be the best option. But if they really wear, the velocity through the valves might be too high and that means the pump might just be too small.
RE: Diaphragm Pumps Wearing Fast
I also agree that it is completely unacceptable for a vendor to not disclose the material of construction. I would drop them like a bad habit.
I recommend contacting a pump distributor. That's why I don't buy from Grainger. Zero support.
RE: Diaphragm Pumps Wearing Fast