Re: Tank air system
Posted: 09 Sep 2009 12:54
What did the stopwatch say?ChristoSlang wrote:Thanks gents!
I'll let SWAMBO operate the stopwatch while I test it on all four four tyres next week :idea:
Nissan Patrol 4x4 (Africa)
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Tank air system
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Re: Tank air system
Posted: 10 Sep 2009 19:01
Hmmm... I never deflated my tyres below about 1.9 bar whilst in Mozambique, so I don't have an answer for you guys yet 
I'll do a decent test this weekend and post the results!
What I can tell you is that the system inflates a double-bed camping mattress in about half a minute once it's fully primed
I'll do a decent test this weekend and post the results!What I can tell you is that the system inflates a double-bed camping mattress in about half a minute once it's fully primed
Re: Tank air system
Posted: 10 Sep 2009 19:30
Thanks Christo, sounds good so far
Re: Tank air system
Posted: 20 Sep 2009 23:26
I finally did some proper testing this afternoon. SWAMBO checked the tank pressure & operated the stop watch, while I did the inflating & monitoring of the tyre pressure gauge on the inflator. We performed three separate tests, each involving a single 33" x 12.5" x 15" BFG MT that had to be inflated from 150 kPa back up to 200 kPa. This is typical of my requirements, except that I did bother to inflate all four tyres.
To establish a base-line I started with the single-head compressor under the bonnet. It is of unknown make, but is sturdily built and looks like a full metal unit. The time taken for this test was 2 minutes and 5 seconds (125 seconds). Next step was to use the new dual-head, tank-equipped ccompressor to do the same. I started off with the tank empty to establish how much of a difference the reservoir would make. Much to my initial surprise the dual-head compressor took 2 minutes and 17 seconds (137 seconds) to perform the same task!
The answer is straightforward - when I connected the hose to the tyre to start inflating, some of the pressure in the tyre rushed out and "inflated" the tank until they both had the same pressure. Once that was done, the compressor had to pressurise both the tank & the tyre simultaneously! Not a very valid test after all? With this oddity explained, we moved on to the next test.
Emptying out the tank again, I started the pump to see how long it takes to pressurise the 8 liter tank from 0 kPa to 750 kPa (where the safety cut-off automatically stops the compressor). This took 2 minutes and 50 seconds (170 seconds), a rate of about 4.4 kPa per second. The compressor performed slightly better initially, slowing down a bit as it approached the 7.5 bar mark. Then for the third & definitive inflation test - and it took only 25 seconds!
Whilst inflating the pressure in the tank dropped from 750 kPa to 360 kPa (a 50% pressure loss), taking a minute and a half to fully pressurise itself again. I guess I'll have to do another test on all four tyres to see how this re-pressurising time balances out against the time it takes to remove the hose, put the valve cap back on, walk to the next tyre, take the valve cap off, attach the hose and start inflating...
To establish a base-line I started with the single-head compressor under the bonnet. It is of unknown make, but is sturdily built and looks like a full metal unit. The time taken for this test was 2 minutes and 5 seconds (125 seconds). Next step was to use the new dual-head, tank-equipped ccompressor to do the same. I started off with the tank empty to establish how much of a difference the reservoir would make. Much to my initial surprise the dual-head compressor took 2 minutes and 17 seconds (137 seconds) to perform the same task!
The answer is straightforward - when I connected the hose to the tyre to start inflating, some of the pressure in the tyre rushed out and "inflated" the tank until they both had the same pressure. Once that was done, the compressor had to pressurise both the tank & the tyre simultaneously! Not a very valid test after all? With this oddity explained, we moved on to the next test.
Emptying out the tank again, I started the pump to see how long it takes to pressurise the 8 liter tank from 0 kPa to 750 kPa (where the safety cut-off automatically stops the compressor). This took 2 minutes and 50 seconds (170 seconds), a rate of about 4.4 kPa per second. The compressor performed slightly better initially, slowing down a bit as it approached the 7.5 bar mark. Then for the third & definitive inflation test - and it took only 25 seconds!
Whilst inflating the pressure in the tank dropped from 750 kPa to 360 kPa (a 50% pressure loss), taking a minute and a half to fully pressurise itself again. I guess I'll have to do another test on all four tyres to see how this re-pressurising time balances out against the time it takes to remove the hose, put the valve cap back on, walk to the next tyre, take the valve cap off, attach the hose and start inflating...
Re: Tank air system
Posted: 26 Sep 2009 10:22
Thanks, Christo this is very usefull.
Re: Tank air system
Posted: 11 Oct 2009 16:40
Hallo Christo
Dit is baie goed gedoen en het self ook al gedink aan dit. As jy stadig genoeg stap van een wiel na die volgende sal die tenk mooi vol wees veral as jy die druk kontroleer, voor jy aan beweeg.
Ek sien jy sal dalk moet reg staan vir 'n paar van die instelasies.
Groete
Louis
Dit is baie goed gedoen en het self ook al gedink aan dit.
As jy stadig genoeg stap van een wiel na die volgende sal die tenk mooi vol wees veral as jy die druk kontroleer, voor jy aan beweeg.Ek sien jy sal dalk moet reg staan vir 'n paar van die instelasies.
Groete
Louis