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  #16   Spotlight this post!  
Unread 02-16-2005, 03:36 PM
scifi3018 scifi3018 is offline
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Re: PRESSURE SWITCH

That is also a reason why not to have to large an accumulator (not legal anyways)
but last year after our season, i wasnt at the meeting the night before an exibitoin we were going to, so the mechanical fools deicided that since our robot was pneumatics heavy (used a lot) that a larger accumulator would be a great idea. So they installed a 10lb 4ga Air tank on our bot. They experimented with it, and since the compressor had to work a lot more, is started to overheat, instead of realizing that they messed something up, they instead put 2 120mm fans near the compressor to cool it down.

When i got back, i was astonished at what the gigantic growth was, and asked about it, and got the answer.

Unfotunatley they didnt understand that 1unit of air at 60lbs provides the smae force as 4ga or air at 60lbs and that the compressor had to work x times harder to fill the large tank, draining our batter (exibition, not 2min mathces)
...
sigh
...
But its all better now, i tok the monstrosity out.
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Unread 08-30-2005, 04:01 PM
KevinCarlson KevinCarlson is offline
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Re: PRESSURE SWITCH

[quote=Mr. Steve]Quoted from the FIRST Pneumatics Manual:


Hello everyone,

I'm doing some research on the internet and happening to into this msg forum. I see you guys are discussing something about pressure switch & control system. Maybe you can help me out. I'm looking at someone's patent and one of the independent claim that person makes is that he uses a pressure switch to turn on a PWM circuit/controller when the liquid pressure is low enough to trigger the switch. The exact claim is " Pressure switch can sense the output pressure, said pressure switch activating said pulse width modulating circuit when output pressure is less than a threshold value". I believe the claim is too broad. I meant people have been using pressure switch and pwm for decades. I'm looking at some proof to invalidate that claim. If you guys happen to know any product or publication out there prior to 2001, please let me know.

Thanks,
Kevin
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Unread 08-30-2005, 05:14 PM
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Mike Betts Mike Betts is offline
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Re: PRESSURE SWITCH

Quote:
Originally Posted by KevinCarlson
Hello everyone,

I'm doing some research on the internet and happening to into this msg forum. I see you guys are discussing something about pressure switch & control system. Maybe you can help me out. I'm looking at someone's patent and one of the independent claim that person makes is that he uses a pressure switch to turn on a PWM circuit/controller when the liquid pressure is low enough to trigger the switch. The exact claim is " Pressure switch can sense the output pressure, said pressure switch activating said pulse width modulating circuit when output pressure is less than a threshold value". I believe the claim is too broad. I meant people have been using pressure switch and pwm for decades. I'm looking at some proof to invalidate that claim. If you guys happen to know any product or publication out there prior to 2001, please let me know.

Thanks,
Kevin
Kevin,

First of all, this forum is for high school students and their mentors who build robots as part of an educational endeavour. As such, your query is not quite appropriate.

Second, I suggest that you contact a competent patent attorney regarding patents. Anything can be patented if it is used in a unique or novel manner or for a unique or novel purpose. I have seen patents awarded for off the shelf bevel washers simply because of where they were used.

Patents are an issue of law which, alas, has little to do with engineering or common sense.

Regards,

Mike
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Unread 10-01-2005, 12:23 AM
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Re: PRESSURE SWITCH

If you fire a large cylinder a few times rapidl, you will notice how quickly the system pressure (at the tanks) drops below 60 PSI, even when you started at 95 - 115 psi. It takes a long time for the compressor to recover and your cylinders may move slower while the compressor is trying to catch up.

If you limited your reservior pressure to 60 psi, the system might never recover during a match if you were trying to operate pneumatics.
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Unread 11-28-2005, 04:00 PM
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Re: PRESSURE SWITCH

[quote=Paul Copioli]If the pressure of the tank is only 60psi, then when I fire the cylinder once I expel all of the air in the tanks. If the pressure in the tanks is 120psi, then I have double the available air to use at 60psi./QUOTE]

If we assume the volume used by the cylinder equals that of the tank, then the amount of air you can get from the tank is one half of what is there - the system will equalize at 30 PSI. That is why you use 120 PSI, so your cylinder can be sure to see the full 60 PSI, just as you stated.

You see, while the compressor can keep up pressure, it is limited in volume (Cubic Feet per Minute). The tanks act like 'pressure inductors', allowing brief periods of high flow volume despite a lower volume compressor.

Besides, isn't more better?

Don
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Unread 12-01-2005, 09:20 AM
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Re: PRESSURE SWITCH

Quote:
Originally Posted by Don Rotolo

If we assume the volume used by the cylinder equals that of the tank, then the amount of air you can get from the tank is one half of what is there - the system will equalize at 30 PSI. That is why you use 120 PSI, so your cylinder can be sure to see the full 60 PSI, just as you stated.

You see, while the compressor can keep up pressure, it is limited in volume (Cubic Feet per Minute). The tanks act like 'pressure inductors', allowing brief periods of high flow volume despite a lower volume compressor.

Besides, isn't more better?

Don
Capacitor, not inductor, and yes, of course more is better
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