Guidelines for care & Use of Dry Solvent Stills [Example]

cylinder valve, inlet fitting, high pressure gauge, or regulator seat. If the high
pressure gauge does drop, retighten the regulator-to-cylinder connection and
repeat Step 1. Should the high pressure gauge continue to drop after retightening
the regulator-to-cylinder connection, the regulator must be removed and returned
for service.
“Never attempt to tighten a cylinder valve or any parts of the valve. If the cylinder
valve is leaking, place the cylinder outdoors and notify the cylinder supplier
immediately.
3. Keep the cylinder valve closed at all times, except when the regulator is in use.
Adjusting Regulator
Delivery Pressure and Flow
1. After the regulator has been securely attached to the cylinder and no leaks exist
(see previous sections), adjust the delivery pressure to the desired pressure setting
by turning the adjusting knob in a clockwise (increasing) direction until the
desired pressure is reached.
2. If the regulator is equipped with an outlet valve (or needle valve), flow can be
regulated by proper adjustment of the valve.
Turning Off Cylinder Valve
“When you have finished using the regulator, close the cylinder by turning the handle
in a clockwise direction and allow all pressure to drain from the regulator. Gas will
cease to flow and the pointers on both pressure gauges will indicate “0” when all
pressure has been drained from the regulator. After all pressure has been drained,
release all tension on the pressure adjusting knob by turning it counterclockwise
(decreasing) until the knob turns freely. Turn the outlet valve, if so equipped, in a
clockwise direction to turn off valve.
Removing Regulator
1. “It is not necessary to remove the regulator unless the cylinder is being moved or
an empty cylinder is being exchanged for a full one.
2. NEVER attempt to remove the regulator if any pressure is showing on either
pressure gauge. Turn the cylinder valve handle clockwise and allow all pressure
to drain from regulator. Gas will cease to flow and the pointers on both pressure
gauges will indicate “0” when all pressure has been drained from the regulator.
After all pressure has been drained, release the tension on the pressure adjusting
knob by turning it counterclockwise (decreasing) until the knob turns freely.
3. Remove the regulator from the cylinder and replace the protective cap on the
cylinder.”
Information on Aldrich regulators can be obtained at:
https://www.sigma-aldrich.com/aldrich/bulletin/al_techbull_al151.pdf
Again, remember that specific regulators are made for each gas used in the lab, and that some
regulator inlet CGA fittings employ left-handed thread rather than right-handed thread. You will see a "V"
notch on the outlet nut fitting for left-handed thread.
If the thread is right-handed, the hexagonal outlet nut fitting will not be so notched, and you can
remove the regulator using a wrench by loosening the fitting in a normal counterclockwise direction
(meaning toward the left as one faces the outlet), or as one anonymous graduate student put it, "Rightie
tightie, lefty, loosie".
DO NOT OVERTIGHTEN regulator fittings while installing them onto the tanks. This may
damage the thread. Slightly more than a good hand-tightening is really all they need. The “ball and socket”
fitting is constructed so as to compress and automatically seal when the tank valve is opened so that the gas
pressure actually tightens the seal, since the metal surfaces at the point of contact are made of malleable
brass or chrome-plated brass. Even if you did not tighten it enough, nothing worse than a loud hiss of
escaping gas would occur - after all, you would not expect the regulator to dislodge itself, like an unwinding
propeller, would you? Most people overtighten regulators, making removal difficult and dangerous.
Pounding on a wrench handle to remove regulators is unwise.
Again, in reference to the “ball and socket” joint connection between the regulator inlet shaft and
the cylinder outlet stem - After the male-threaded regulator and female-threaded cylinder fittings are
connected, this is the airtight seal between the two pieces of equipment. This is the area which requires the
most cleaning. Sometimes microscratches develop in the “ball and socket” area, resulting in slow gas leaks.
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