Another Quincy Compressor Question?

How long should it take a 5hp, Quincy 325 2 stage pump to fill an 80 gallon tank. I'm trying to determine if the compressor is operating efficently.
Thanks.
Joe...
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4 minutes, 18.739 seconds... more or less

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Thanks Tom. I'll time her over the weekend. I'm thinking that it's taking longer than that :-(.

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I forgot to ask...pump rpm?

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On Mon, 16 May 2005 23:20:17 -0400, the inscrutable "JB"

I'll let you silly top-posters figure out what order those posts and replies go in...
Question that come to mind are "Why are you having to start from zero PSI? What leaks which would cause that? Why don't you fix THAT? And to what PSI are you pressurizing?"
------------------------------------------ Do the voices in my head bother you? ------------------------------------------ http://diversify.com Full-Service Web Development
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JB I would think that there are some variables here that you need to give up to the group so that an educated guesstimate at the answer can be made. Are you filling from 0psi to whenever the switch kicks out. What pressure are you filling to? How about you publish the time that it takes to fill the tank from kick on pressure to the kick off pressure, and what these pressures are. If your kicking out at near the max pressure of the pump then its going to take a lot longer to fill that if you lower max pressure. Max pressure is about 175psi ( I think) on a two stage and if your running to this pressure or above its going to take a long time. Also consider that the pressure switch may be going haywire and not shutting off reliably. If you google this newsgroup you will find this discussion has taken place in the last year or so. lg no neat sig line

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gallon
Mine turns on @ 150 PSI and off @ 175 PSI. It takes 1 minute 20 seconds. Don't have a clue how long it takes from 0 pressure, I rarely turn mine off. I have 3 phase delta service and an identical compressor.
Harold
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I have been tryi ng to figure out why my compressor leaks down and will eventually empty after about a week. I finally narrowed it down to the pressure switch. Anyway, it is currently set to turn on at 145lb and off at 175lb. Except for the slow leak, the pressure switck works fine. It is a square D brand. I am looking for a source to get a replacement.
Thanks afor all the help.
Joe...
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efficently.
seconds.
at
Interesting that it's the pressure switch leaking, although not much of a leak. Fittings tight? Soap might show where it's leaking. Graybar is a Square D dealer.
Harold
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You might have a very small leak around the edge of the pressure switch diaphram. See if there are screws in a circle around the section that sandwiches the diaphram to the bottom of the case. Just don't try to remove the screws while the tank is pressurized.
If you can snug the screws a bit, it may stop the slow leak. If it leaks after snugging the screws, you might need a new switch, although a good Square D product/parts distributor might be able to locate a new diaphram for your specific switch model.
WB ................

at
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Wild Bill,
Thanks for posting. I did snug up the screws around the edge of the pressure switch diaphram. They were in fact lose and tightening them dramatically slowed the leak. Unfortunately, it still leaks. I will probably have to replace the switch.
Thanks again for the help.
Joe...
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Why so much pressure?

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Ask Quincy. They come that way, likely because higher pressure is used to provide a larger supply of air (at lower pressure). These are compound compressors with a cooler between cylinders, and what I consider to be slow speed machines. They do not resemble the small high speed clatter boxes that are marketed as compressors. They're serious machines.
Harold
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on. I don't need higher pressure, it's safer and the Q's WILL last forever! Is there a cost advantage?
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PSI and off @ 150. I use a slightly modified auto air suspension compressor to fill the tank, which is quite large, but I can pre-fill it with the Quincy if I desire. Couldn't do that with the lower pressure.
Quincy makes more than one model compressor. Could be you have models different from the ones in question, or yours have been set with different operating pressures intentionally. Are they dual stage? Do they unload?
I went to the dealership where mine was purchased to buy a seal for the crank, which had started seeping oil----when the compressor was something like 20 years old. I inquired at that time what it would cost to replace the compressor and was shocked to find it was something like $3,000. I had paid about $1,000 when I purchased it, new. They had introduced a lesser expensive model that was being sold with similar specs. Can't help but wonder if maybe that's what you have. I've noticed that single stage compressors are operated at lower pressure than are the compound models. At any rate, the turn on and turn off pressures were factory preset and have never been altered. Did you buy yours new, and are the controls set as manufactured?
Considering mine is over 34 years old at this point, and is still pumping dry air (no trace of oil) and has had virtually no trouble (leaking gasket and leaking seal), I'm not convinced I should be worried about how long it will last. It has hydraulic unloading, so it starts load free. High pressure isn't an issue in that regard.
Harold
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I have two #325 and one #qr-25 I can't tell them apart and the parts all seem the same. They are all 2-stage and will do higher pressure. We bought just the pumps over the years and mated them into our existing system so nothing is factory OEM. Our back-up is a 10 hp "Hydrovane" that we run for a day every quarter to service the Quincys. They get fresh oil and a valve cleaning. We try to track-down leaks that will drain the two 80 gallon tanks in about 5 minutes after shut-down but seem to only find the most blatant. I'll bet I'm paying twice as much for air as I should.
PSI and off @

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bought
for
valve
That's a damned shame. I never turn mine off. I have a couple very old nozzles I use, one on the mill, one on the lathe. They're the type that aren't OSHA approved, with no safety vents. I really like them, so I use them, and I'm the only one that has access to them aside from Susan. OSHA isn't a factor. As long as they are well lubed, and the insert is properly tightened, they don't leak. Even with my compressor set @ 175 PSI, it will often not start once a day, so I'm obviously not losing much air.
I rebuilt all my Milton connectors (something like 20 of them), replacing the steel valves with stainless ones that I made, and made new gaskets (which I also made), so they do not leak. I imagine it's nearly impossible to have an air system totally air tight, but yours sure sounds like it's pretty porous. Imagine if you ran higher pressure!
I have a manifold system and ball valves on my setup so I can blow down easily. It discharges outside, so there's no mess. It's one of the best things I've ever done for my air system because I now blow down daily, and it takes but a few seconds.
Harold
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We used to have two taps at every drop, one would be 125 psi and the other regulated to 30 psi for blow guns. Each tap was a different style of connector so the people couldn't plug a blow gun into the High pressure. In those days there weren't safety blow guns. Somehow, we ended up with just the one style and of course, they are hard to find and expensive and there are well over 100 of them. Every six months or so, I try to get everybody to track down all the leaky fittings, We rebuild the fittings and make new rubber washers for them and it's better for a while. I do believe it would be cheaper to replace ALL the fittings with cheaper, more popular fittings, I'd say $600 P+L, than run 15 HP twice as long as I should have to, about 60 to 70% run time. I'll have to do the math and see when the pay-back is. But, I certainly love my Quincys!!! I wish I had other no-brainers.
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snip----

Yep! Of all the machinery I've ever owned, I can't think of one other that has been so reliable and trouble free. They truly are a nice piece of equipment. Here, in timber country, the skidders are pretty much all equipped with one of the 10 horse heads. If you've ever seen how such equipment is used, you'd likely understand that a piece of junk wouldn't last a day.
Mine has the old type oil pump, which apparently had given some trouble. I know that's one of the things they changed with later models. I've never had the slightest problem even with that.
I have a distinct advantage as compared to you. Regardless of the quality of employees, once you have a herd of people using equipment, things have a way of degrading. I'm not surprised you have so much leakage, and I'm not implying that it's intentional. When you're the only person using the service, it's immediately apparent when there's the slightest problem and you can deal with it.
I'm not convinced new fittings would solve the problem. Have you given any thought to changing the nature of the seals? Maybe something softer, so it takes less effort for them to seat? Also, are your lines iron? Rusty? I violated all the rules and installed 1/2" PVC pipe after experiencing rusty iron pipe, but before you jump to conclusions, understand that virtually 100% of them are cast in concrete, where they can't explode violently. The system has worked beautifully so far, to which I attribute my dry air. Any oil could change that in a hurry. I realize you can't use PVC, but getting away from iron is a great idea, assuming you're using it. Had I not been placing my pipe in concrete, I'd have used copper. I explored the ABS air lines but realized that I'd have to rob a couple banks to afford it. Nice stuff, but very pricey.
Harold
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I love: "herd" of people, on SO many levels. At least there are drip legs with valves and filters and oilers EVERYWHERE but the lines are all 3/4" black pipe. I may tirade about anything other than black pipe but the next leg we do will be in copper! Quick math: 40 amps, 9600 watts, 9.6kw/hr $.15/kwh = $1.44/hr $1.44/hr * 70% duty= $1.008/hr cost for air. Lets say I'm wasting $.40/hr. $600 = 1500 hours payback. Compressors run 2000 hrs/yr. Leaks cost $800/yr. Math sound fair if not conservative?
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