Hydrogen Supply System - UAlberta-EcoCar/wiki GitHub Wiki
This page is for providing details on how hydrogen gets from the cylinder to the fuel cell. Diagrams and specifications like tubing materials and valve part numbers are to be detailed here. Note, info given is for Sophie, but Alice/urban concept vehicles use the same parts, and would follow a similar logic, principle differences might be whether purge valve is outside the enclosure, and placement of flowmeter.
In Canada and USA, the common fitting is CGA 350, including at SEMA. In Europe, a different standard was used.
There are 3 principal types of fittings used in the hydrogen system:
Tube fittings are the standard/default swagelok fitting/thread type, and are used whenever a tube fitting is "Swaged" onto a some tubing. Overtightening will eventually damage tubing, so tighten lightly after initial swaging. No teflon tape is required.
NPT aka "ISO tapered thread" is a type of thread that is tapered, and is designed for metal on metal connections. Sometimes, the taper means that the threads are basically crushed to form the gas tight seal, this varies though. Thus, pay attention to types of materials used. A brass on steel connection is preferred, the brass piece will be the "sacrificial" component and the steel component will be minimally damaged. For these connections, try to minimise number of connection cycles, as they're prone to wear. Teflon tape will be required.
G fittings, aka "ISO parallel thread". These fittings have the same nominal diameter and thread spacing as NPT, but are parallel threads rather than tapered, thus no damaging of mating components is required. To form seal, a washer or as single layer of teflon tape can be used. At SEM, only a washer is allowed for flowmeter (no PTFE tape).
[Tank]
{350 CGA - to - 1/4in NPT union}
[Regulator]
{1/4in NPT-to-1/4in tube union}
{1/4in Tubing}(Approx 1", Note: S.Valve as close as possible to Regulator according to SEM rules)
{1/4in - to - 10-32 UNF Union}
[S_Valve]
{1/4in - to - 10-32 UNF Union} (note: unable to find 10-32 to 5/16in union, or 5/16in to 1/4in bulkhead union...would simplify things if we could find. FC stack inlet and outlet are 5/16in tubing.)
{1/4in tubing}
{1/4in - to - 5/16 in union}
{5/16in tubing}
{5/16in Elbow}
{5/16in tubing}(approx 1 in)
{5/16in Bulkhead union}
[FC-Enclosure]
{5/16in Bulkhead union}
{5/16in tubing}(approx 10 in)
[Exit]
[Tank]
{350 CGA - to - 1/4in NPT union}
[Regulator]
{1/4in NPT-to-1/4in tube union}
{1/4in Tubing}(Approx 1", Note: S.Valve as close as possible to Regulator according to SEM rules)
{1/4in - to - 10-32 UNF Union}
[S_Valve]
{1/4in - to - 10-32 UNF Union}
{1/4in tubing} (approx 6")
{1/4in - to - G-1/4 union}
[Flowmeter]
{1/4in - to - G-1/4 union}
{1/4in tubing}
{1/4in - to - 5/16 in union}
{5/16in tubing}
{5/16in Elbow}
{5/16in tubing}(approx 1 in)
{5/16in Bulkhead union}
[FC-Enclosure]
{5/16in Bulkhead union}
{5/16in tubing}(approx 10 in)
[Exit]
| Common Name | Manufacturer Name | Part Number |
|---|---|---|
| 5/16in Tubing | CrackResistant Teflon® PFA SemiClear Tube for Chemicals, Flexible | McMaster-Carr 51805K87 |
| S.Valve and P.Valve | 411 Series 2-Way Miniature Solenoid Valve | ASCO 411L3112HVS |
| Backup Valve (Manifold mount) | 411 Series 2-Way Miniature Solenoid Valve | ASCO 411M3112HVS |
| Manifold for backup valve | STANDARD GENERAL SERVICE MANIFOLD ASSEMBLIES | ASCO 51140001-01 |
| Pressure Sensor | INDUSTRIAL OEM Pressure Transducer AST4000 | AST4000-A-V0025-P-3-A-1-000 |
| Swagelok fittings | Many many, see packing slips inside the fittings box | Too many |