Valve to fill additional compressed air tank

================= Check valve from compressor to primary tank, another from secondary to primary. Normally-closed solenoid valve from compressor to secondary, opens when primary >90PSI. Can be switched off. Primary feeds shop air line.
Compressor fills primary first to 90PSI, then solenoid valve to secondary opens, check valve into primary closes as compressor outlet pressure drops. Compressor brings up secondary.
If primary drops 90, compressor returns to filling secondary.
Normally secondary supplies airline via check valve into primary, is refilled through open solenoid valve.
When demand is too high and pressure drops below 90PSI, solenoid valve closes so compressor discharges into primary, as does secondary through the tank-tank check valve until the demand drops below compressor capacity. Then the compressor refills the primary, and then the secondary.
I think that covers everything. jsw
Reply to
Jim Wilkins
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That's a big "maybe". If you stanch all the leaks, tanks and lines will be full at startup, so where's the delay?
Reply to
Larry Jaques
Here is what I would use. The 60cfm model.
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It will open and allow flow to the secondary tank at 120psi and block the flow when the primary tank drops to 90psi. A parallel line with a check valve to allow flow from the secondary to the primary would allow both tanks to supply the system below 90psi.
Reply to
aasberry
With a little additional programming, the pressure transducer information could be used to get a little more run time at pressure. For example you could measure the rate of pressure change when the compressor is running but no air is being used. The rate of change for the compressor can be compared to current rate of change of air usage. If air is being used as fast as or faster than what the compressor can keep up, you can turn in on before 90 PSI to give you more run time at pressure than you'd get waiting until 90 PSI to turn it on. Not sure that it would help you much but set points that vary with demand can give you more air.
RogerN
Reply to
RogerN
Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:
For what it's worth, I ran through that about two years ago. It took a while to replace all the chuck o-rings, and find bubble-bleeds from a few threaded fittings. But now, when the compressor shuts off at night, it doesn't come on again until I use air the next day.
I still have to remember to remove TOOLS from any drop lines, because tools seem to almost always leak a little.
A good "Monday Morning valve" set for daily on/off will accomplish almost the same thing without quite as much fuss.
Lloyd
Lloyd
Reply to
Lloyd E. Sponenburgh
Sounds like you have a bad leak if the system won't hold air overnight.
Filling the extra tank through a throttle valve and delivering the stored air through a check valve will do what you want, but the energy efficiency will be around 50%. It's the same story as charging a battery through a resistor. A manually-operated valve would be better if its operation can be timed to miss the demand peaks.
If your peak loads are sufficiently infrequent (once in ten compressor cycles or some such) the resistive reservoir charging might be useful. For my part I'd try to make the system hold pressure when the shop's closed. Compresed air is basically money.
Hope this helps,
bob prohaska
Reply to
User Bp
I've had a Load Genie on my compressor since the 70's. It tends to jam from sideways loading on the inlet pipe, which expands when it heats up. Sometimes the Load Genie waits a minute or two after the compressor shuts off before unloading. jsw
Reply to
Jim Wilkins
Actually, if you think about it, the compressor will run continuously from the time the pressure hits 120, until such time the reserve tank is filled. All the while, the system pressure will never drop below 90.
During filling, no energy will be lost, unlike with restricted valves.
i
Reply to
Ignoramus31823
This is EXACTLY what I wanted to do, except the filling valve should open at 120 and close at 90. Thanks for explaining.
i
Reply to
Ignoramus31823
Over 2 years.
I have a lot of compressed air piping, a lot of it under the ceiling.
Reply to
Ignoramus3322
I do not think that I can get more run time with that, and I definitely do not see the benefit worth diong software, adding computer etc.
i
Reply to
Ignoramus3322
Interesting. There are several items listed. Do you mean item "NLG-1"?
i
Reply to
Ignoramus3322
Exactly. Like charging battery through a resistor.
A pressure controlled solenoid valve would be better.
I think that I should try to get my act together and find leaks. Plus the dryer dumps a bunch of air every 2 minutes, very annoying.
i
Reply to
Ignoramus3322
Shaving the gray hair off the Genie's inlet pipe should help the old guy.
Reply to
Larry Jaques
About the run time, let me see if I can explain it better. For example, let's say your sandblaster needs at least "X" psi to operate correctly. Now if your sand blaster drains your tanks at 15 PSI per minute, and your compressor adds 10 PSI per minute, then with the compressor on, you have a loss of 5 PSI per minute. So if you could detect usage rate > compressor rate, and turn on the compressor at 120 PSI instead of 90 PSI, you get 6 minutes of usage at a loss of 5 PSI per minute, from 120 to 90 PSI. With the compressor off, you get 2 minutes from 120 to 90 PSI.
I understand at this point the computer idea sounds too complicated / expensive but that's kind of like your EMC experience. Sounded like too much unfamiliar territory but you took it step by step, solved one problem at a time, and ended up with a system that you can repair without high $$ parts and labor. And you added a 4th axis + knee?, that may not have even been an option with the original control.
If anything like this ever seemed practical, options include a micro PLC with analog input or something like an Arduino board, $30, has analog inputs, free software, screw terminal add on for around $8. The 5V output from the microcontroller can be used on AC or DC solid state relays to control valves and/or magnetic contactors. So it's actually nothing like using a PC and trying to interface to a compressor. Or perhaps some of you scrap deals could have a controller in them that could be reprogrammed for other tasks.
RogerN
Reply to
RogerN
"Ignoramus31823" wrote in message news:0emdneOeB6GlDjnPnZ2dnUVZ snipped-for-privacy@giganews.com...
90PSI was a placeholder to simplify the explanation.
Your unloader may require another check valve going into the secondary tank. jsw
Reply to
Jim Wilkins
Right. I already found two 1/2 inch check valves, with manual valves on them also. If I do add a tank it should work out pretty good.
i
Reply to
Ignoramus3322
Yes, NLG-1. With this and the check valve, there is no need for electrical power to operate it.
I've had a larger model 140/175 on a service truck compressor for over 30 years. It is for constant running of the gas engine. When it builds to 175, the air is dumped overboard. It is loud. I put a lawn mower muffler on it. That is where you would connect to your secondary tank.
Reply to
aasberry
OK, thanks, this is cool if I can do it without electrical connections, much better. This is what I was sort of hoping that I could find. Thank you
i
Reply to
Ignoramus3322
OK, couple more question.
1. For my application, I need to simply connect my compressed air system to the inlet, cap the "outlet" connection, and connect tank to the muffler connection. Right?
2. Is it piloted or does it get pressure from the input line?
i
> I've had a larger model 140/175 on a service truck compressor for over > 30 years. It is for constant running of the gas engine. When it builds > to 175, the air is dumped overboard. It is loud. I put a lawn mower > muffler on it. That is where you would connect to your secondary tank.
Reply to
Ignoramus3322

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