Fp regulator mods

[Greg Hermann]

>At 03:21 PM 1/11/99 -0700, Greg wrote:
>(snip)
>>Another possibility, if you want REALLY accurate control, would be to
>>REDUCE the size of the port
>
>    Which port; return, input or valve?

The valve port.
>
>>in the Mallory valve down to about .060"

Maybe .125", tho.

>>diameter (with a bushing), get the control rate the way you want it as
>>discussed above, and then use the Mallory regulator as a PILOT valve to
>>operate an industrial grade control valve with a BALANCED port,

Basically, the valve is arranged so that motion of the valve's plug so as
to open or close its port is neither resisted not aided by the pressure
differential across the valve.
>
>    Please explain how a BALANCED port works.

What the above means is that it takes very little force to move the valve's
plug through its full range from open to closed.

>    Also, would the Mallory return port feed the IGCValve?  I am having
>trouble SEEING the final product; how would the fuel get back to the tank?
>

The output flow from the Mallory valve, acting as a pilot valve is what
would open the main valve against a fairly light spring. You would pipe the
output of the Mallory valve to the actuator port of the main valve.
Usually, the main valve will have an internal orifice which bleeds this
actuation pressure to the return line, but the bleed orifice can also be
piped external to the main valve. Basically, when the fuel pressure is high
enough to open the pilot valve, the relief flow through the pilot valve
acts to open the main valve. If the fuel pressure drops below the control
point, the main valve closes in response to the lack of relief flow from
the pilot valve.
>
>
>>and with said port sized correctly for your particular flow situation!! >Said
>>industrial valves in the size range we are talking about would prolly set
>>you back about one portrait of Ben (otherwise known as a "fun coupon"!!)
>
>    Where can I get a balanced port industrial valve and how do I explain
>to them what I want?

I think I would be inclined to pick one intended for use to control
refrigerant flow, since refrigeration systems very commonly use their own
refrigerant to operate the system's control valves--they do it this way in
order to minimize the number of packings, etc. which might leak refrigerant
to the atmosphere--which is just what you want with a fuel system. These
valves are even OK to use with propane (it is sometimes used as a
refrigerant, particularly in refineries, where it doesn't much matter if
there is one more thing around to go BOOM!!).

Manufacturers of sontrol valves intended for use with refrigerants include
Parker/Refrigerating Specialties, Alco, Sporlan, Hubbell, Hansen/Danfoss,
Phillips. The valves can generally be had in either brass or ductile iron
(iron only in sizes way bigger than we would be interested in.) Be happy to
try to pick out a couple of part numbers if numbers are available as to
fuel flow, pump size, etc. A typical  HVAC&R wholesaler would be an
appropriate place to order/buy one. Some of the mfgr's will sell direct.
Get hold off list, and I will see if I can dig up a copy of a sectional
view of a valve like I am talking about to clear up your picture.
>
>>Regards, Greg
>>
>>
>>