This entry describes the new solvent vapor annealing setup with active control of vapor pressure enabled by mass flow controllers.
The system is based on Mass Flow Controllers, Model 2620A (flow up to 1.00 SLPM standard liter per minute), from Omega engineering.
0. Plumbing (manual, p. 7) : Do not use pipe dope or sealants. Use PTFE tape, but do not wrap first two threads to prevent bits of tape from getting into flow stream. Use sintered filter on inputs (McMaster-Carr PN 98355K831 is 1/8 NPT male pipe fitting filter with 40 micron pores).
1. Communication is via 8-pin miniDIN port. Ray terminated cable with male DB-9 connector, according to pin-out on manual, p 8. For communication with asyn port, use RJ45-DB-9 adapter with all 9 pins connected straight-through at the port. For the connection to the MFC cable, use RJ-45 to DB-9 adapter that only connects pins needed for RS232 communication (manual p 10):
DB-9 8-Pin miniDIN
Pin 5 Ground Pin 8
Pin 3 Transmit/Receive Pin 3
Pin 2 Receive/Transmit Pin 5
2. Always connect gas flow to input of MFC BEFORE trying to turn on the flow of the MFC. MFC can overheat when you ask it to deliver flow when input gas is not present.
3. Set flow on MFC with commands/macros like these:
def dryflo '
local florate
florate=$1
flostr=sprintf("%s%2f1", "AS", florate )
eprint flostr
epics_put("8idg:asyn_11.AOUT", flostr)
'
def drymed '
epics_put("8idg:asyn_11.AOUT", "AS0.5")
'
* Note flow-rate between 0.0 and 1.0 slpm (standard liter per minute)
* Note usually configures Asyn 20 is wet loop, asyn 11 is dry loop
See ~8IDGUSER/local_macros/leal/rh_control.mac for more (similar) macros.
4. Gas washing bottle for wet loop is Fisher part number 03-0305, 250 mL polypropylene bottle with polyethylene fritted disk. Need ~ 50 mL solvent to cover the frit. (https://www.fishersci.ca/shop/products/bel-art-scienceware-gas-washing-bottle-fritware-dispersion-disc/03035)
Glass wash bottles also available.
Attachments:
1. Manual for FMA-2600A series Mass Flow Controllers (https://www.omega.com/manuals/manualpdf/M3791.pdf)
2. Configuring asyn ports for serial communications with MFCs |