AquaMist pump (was: Re: Voltage controller)

[John Andrianakis]

Havent followed all the messages of this thread but I think you should know 
that erl does not alter the water output by changing the pump supply 
voltage. They use a solenoid valve controlled by their MF-2 injector 
controller. The pump is specialy designed magnetic piston unit and I could 
guess that it operates at a frequency of around 10Hz.
Regards,
John Andrianakis.

On Sunday, March 07, 1999 7:00 PM, rr [SMTP:RRauscher at nni.com] wrote:
> Now I got it!
>
> I think that you need to do some testing with this unit. If you
> modulate the control signal at about 4Hz, you can probably do
> what you want. The reason for this slow, is to still allow the
> pump to give full cycles.
>
> The PWM controller may work for this, it will need to be slowed
> down. The .1uf cap hangin off pin 2 will need to be made larger
> in value. Something between 1 & 3.3uf might be enough.
>
> As you mention below, you can try to vary the pump volts in
> order to slow the pump down. But this gets messy with all the
> heat build up and pump stalling at lower voltages.
>
> Let us know what you find...
>
> BobR.
>
>
> Daniel Houlton wrote:
> >
> > rr wrote:
> > >
> > > OK, finally got into this site (it can be reeeaaallll slow). This is
> > > an interesting pump. Basically, it is a solenoid driven pump. Figure
> > > a bicycle pump with a magnetic solenoid pulling back the rod, then a
> > > powerful spring returning the rod to the original position to pump.
> > > The pump stroke is run at about 50Hz.
> > >
> > > There are electronics built into the pump itself, no separate
> > > controller.
> > > According to the schematic, the input siganl is just an on/off as the
> > > water is required. They use a pressure switch.
> > >
> > > Bottom line,  Dan, I don't think that you need anything else to drive
> > > this pump. It's all self-contained...
> >
> > Yeah it looks that way, but it can still be controlled to vary the
> > amount of injection by controlling the pressure.  The basic system
> > comes with an on/of pressure switch which means you get all or none.
> >
> > Their upper-level kit includes their fuel injector control box which
> > also has an output for this pump.  It increases pump pressure and
> > therefor the amount of water injected as the boost pressure goes up.
> >
> > That's basically what I want to do.  Provide a variable voltage signal
> > (looks like 0 - 12V) to increase water pressure as boost goes up.  If
> > I could get this signal from the 0 - 5V a MAP sensor gives, I can get
> > a nice water injection curve instead of turning it on full blast at X
> > psi with a pressure switch.
> >
> > Use the pressure switch that comes with the pump to arm the system
> > and prevent injection before 3 psi say.  Then map the MAP output so
> > that the pump gets about 6V (half pressure) at say 3 psi and then ramps
> > up rapidly to deliver 12V (full pressure) by 8 or 9 psi.
> >
> > Someone mentioned an op-amp could do this.  Also a 555.  What is a
> > 555?  Is that a particular op-amp?  I remember it being referred to as
> > a timer someone used to drive and additional injector from the signal
> > to a stock one.
> >
> > For now I'll start studying op-amps.  Thanks for the help.
> >
> > --Dan