DIY injector cleaning

[swagaero]

Bruce Bowling wrote:
> 
> >
> >  Andris,
> > i guess the answer was NO there isnt a GOOD way for the DIY to clean injectors other than a additive in
> > the tank.
> >
> > Jimm L.
> > the injector " guru"
> >
> >
> 
> A question:
> 
> Could one accomplish a sort of ultrasonic cleaning by simply driving the
> injector coil at a high frequency, like 10 - 30 Khz, while backflushing?
> Seems to me if one got the duty cycle right one could get the pintle to
> just open and close slightly, producing an active high-frequency "hammering"
> on the pintle. This, with the backflushed cleaning liquid under pressure,
> should help clean the unit.
> 
> So drive the injector with a 555 timer coupled to a driver transistor. The
> following circuit comes to mind:
> 
>   +12       +12                   +12
>    |         |                     |
>    |         |                     |
>    |     ----------             Injector
>   30K    |  4,8   |                |
>    |     |        |            b   |c
>    |-----|7 555  3|----330ohm--- TIP120
>  130K    |        |               NPN
>    |     |6,2 1  5|                |e
>    |     ----------                |
>    |      |   |  |                gnd
>    --------   |  |
>    |          | 0.01uf
>  470pf        |  |
>    |         gnd gnd
>   gnd
> 
> The 555 timer is running at 10 Khz, at about 55% duty cycle. The drive transistor
> is a TIP120 Darlington (NPN). Due to the duty cycle, the drive current should
> be fine for any injector 2 ohms and up.
> 
> All parts are stocked at Radio Shack, and the whole circuit will cost under $10.00,
> including perf board. This is as DIY as it gets.
> 
> - Bruce
> 
> --
> -----------------------------------------------------
> <<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> -----------------------------------------------------
>                  Bruce A. Bowling
>                  Staff Scientist
>    Thomas Jefferson National Accelerator Facility
>     12000 Jefferson Ave - Newport News, VA 23606
>                  (804) 249-7240
> bowling at cebaf.gov  http://devserve.cebaf.gov/~bowling
> -----------------------------------------------------
> <<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> -----------------------------------------------------


Circuit works good I made one to clean Injectors I bought a 20 gallon
barrel of ZEP Carb Cleaner worked good. I never had one come back or
fail on my projects.

Steve
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