Bill,
¼” ball valve with a miniature geared motor directly driving the shaft. You
can cut down the supplied handle to use its stop tab to limit the turn to 90
deg. I’ve used that solution before a few times. It’s a CHAD solution but it
works (even to 1000psi and beyond) and won’t provide a significant mass
penalty. Miniature geared motors come in various gear ratios to provide
solutions of significant torque. You can simply mount the valve and geared
motor to a piece of 3mm ply or MDF via zip ties and voila…
BTW: yes the Chinese cheap ¼” ball valves are good for the job.
Regards,
Troy
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On ;
Behalf Of William Claybaugh
Sent: Friday, 9 October 2020 7:52 AM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Vibration Tolerant Pneumatic Valve
Wyatt:
This is a normally closed valve so only spring force is keeping it closed;
given the strong “organ pipe” longitudinal vibration in solids—which my vibe
table is not duplicating (it’s intended for vibrating mixed propellant under
vacuum)—I’m suspicious that spring force is simply not going to do the job.
A ball valve with a solenoid actuator (on a lever) seems a better bet for
staying closed but adds complexity and cost. I’ll have to chew on it; perhaps
a ball valve with pyro activation would be simpler?
Bill
On Thu, Oct 8, 2020 at 2:06 PM Wyatt Rehder <wyatt.rehder@xxxxxxxxx
<mailto:wyatt.rehder@xxxxxxxxx> > wrote:
A simple solution might be to use a NO solenoid, as you might be able to spice
up the actuator a bit and get the electric closure force stronger than the
spring return force. That might be enough to keep the leaks away. In a similar
vein, are you able to change the orientation of the solenoid to the vibration?
Or is the vibration axis pretty random.
Next option (which I haven't tried) they do make rotary solenoid actuators.
Which you could pair with a ball valve. That should be pretty immune to
vibration. But I can't attest to how reliable they are.
-Wyatt
On Thu, Oct 8, 2020 at 9:59 AM William Claybaugh <wclaybaugh2@xxxxxxxxx
<mailto:wclaybaugh2@xxxxxxxxx> > wrote:
Testing shows that the Lake Axial Solenoid valve in my pneumatic payload
separation system is leaking at 125 psia despite a 1000 psia rating (two
valves tested, both leaked); the leak is through the valve and caused the
latchup of the payload to the vehicle to fail within an average of four
minutes. Additional testing on my vibe table showed latch failure in less than
one minute in ten tests.
Can anyone suggest a solenoid valve good for at least 250 psia and unlikely to
leak under vibration?
Alternative suggestions to using a solenoid valve are welcome.
Thanks,
Bill
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