Defueler?

[ajgiorgi]

I was at the SJC airport and they had a defueler at the station. I know what it does, but why would somebody use this? I'm curious.

[CNGfamily]

Re: Defueler?

I was at the SJC airport and they had a defueler at the station. I know what it does, but why would somebody use this? I'm curious.

Maybe to reduce the CNG pressure in a bi fuel system to allow work on the pressurized portion?

[Curtis]

Re: Defueler?

Could also be a remote fueling hose to transfer fuel from one cng vehicle to a stranded cng vehicle.

[RaulLasVegas]

Re: Defueler?

So bottles can be put on planes?

Do we win a prize if we guess right?

[cnghal]

Re: Defueler?

Most defueling stations are setup to depressurize/evacuate a high pressure cng system prior to service of the vehicle. Some repair facilities by code or by lack of a methane detection/evacuation system are not permitted to work on or store indoors, vehicles with pressurized systems. Most defueling systems capture the gas and feed it back into a blowdown tank for use by a compressor instead of venting into the atmosphere.

Another use/system that I have been approached to build, is a mobile defueling/fueling rig for ngvs for indoor exhibitions. Fire marshalls usually require a minimum of fuel in vehicles being displayed and stored indoors.
The alternative was to drive around the convention center for 3 hours to run down to an 1/8th of a tank and then hope you have enough fuel after the expo to make it to the closest station.

[provo19]

Re: Defueler?

Is there a way to release pressure from your tank into a stranded vehicles tank? i would like to have that ability in case my cng buddies find themselves empty.

[cnghal]

Re: Defueler?

Provo,
Sorry, I didn't finish the post (was rushing to get out the door).
For defueling an NGV, it must be plumbed for it, let me explain:
Most NGVs and those that conform to NFPA 52 are plumbed with two check valves, one in the fueling recepticle (usually the center), and another further downstream before the tanks. To defuel, you must have a seperate defueling recepticle on the mainline from the tanks or a bypass valve to bypass the second check valve.
A special defueling nozzle will, when attached, push in the center/check of the recepticle allowing fuel to pass.

I believe the question you asked was about emergency fueling. There are several ways to do this. Let me say first, the only legal way to transfer fuel from one vehicle to another is if the donor vehicle runs either dedicated or bi-fuel on CNG. You can not have an extra tank with a fueling hose and nozzle attached to it, that you just throw in the back when you need it. Now that that has been said, here's a couple of ways I have done emergency fueling in the past.

First Way - A Transfer Hose.
There are companies that sell a fueling rig (defueling nozzle, ground clip and wire, hose and fueling nozzle for transfering from one vehicle to another. You will still need to bypass the second check valve in your vehicle with 2 tees and a 1/4 turn valve or a 3 way valve (fuel, off, defuel).

Second Way - A Service Vehicle.
In my current work truck, a 95 Dodge 3500 Van, I installed, plumbed, shielded and vented 3 type 4 Lincoln Composites 12GGE cylinders inside the van giving me a total 53GGE storage at 3600psi and a highway range of 750-800 miles. After the last tank in series, I plumbed in a 1/4 turn valve for each tank, a tee with a pressure gauge, a 1/4 turn shutoff valve and a fueling hose and nozzle with breakaway. I installed a dummy recepticle to hang the nozzle from and plumbed the fueling vent line thru the floor a out the other side of the van. I also installed a grounding lug to the tank end of the fueling hose. From the grounding lug I ran a 4 guage stranded wire to a copper plate with spikes that I set on/in the ground to dissipate any static from fueling.
I pull up beside the vehicle needing fuel, turn on my hazards and amber rooftop strobes, open my side door and pull out and attach the nozzle and set out the ground plate. Open the 3 tank valves one at a time until I hear the fuel stop flowing then close that valve and open the next one.
I can give an 18GGE van about 15GGE this way.
BTW, I charge the same rates as a tow truck plus fuel and have yet to hear a complaint. I even fueled a van going cross country at the Clean Energy station in Tucson that was closed and awaiting repairs.
Selling fuel to customers at thier station, Ahhhhh good times!

[300mileclub]

The local community college automotive vocational school has a CNG big rig and a transfer hose. The hose couples to the truck s defuel port and has a NGV1 nozzle on the other. It is used to fuel a CNG vehicle that has been converted or serviced so it can drive to a nearby public fast-fill station. From time to time, the big rig is driven to the same public station to refill its twin saddle CNG tanks.

Hooking the two vehicles together is straightforward, and the pressure gage on the truck fueling panel is used to indicate when to stop the gas flow. At this point, the hose is still pressurized. A defuel port on the truck panel is then used to vent the transfer hose so it can be disconnected from the car or van. In this manner, an out-of-fuel car can be fueled without needing a CNG station.

Transfer hose, because of the truck defuel panel, no longer needs a vent lever on the hose nozzle. The transfer hose is normally sold with a delrin bushing that fits in the car nozzle end to keep it open when defueling the truck while the other end of the hose coupled to the defuel nozzle. Hose unit costs about $1200 from a truck CNG tank installer.

CNG_Defuel.jpg

[cnghal]

Wow, I've been selling these way too cheap.

[300mileclub]

NGV Journal February 27, 2018 - New WEH defueling nozzles available for discharging CNG tanks

The nozzles are equipped with push-pull actuation and the unique WEH® Jaw locking mechanism for extra-easy operation. The nozzle must be attached to the receptacle and the sliding sleeve must be pushed to the front to create a pressure-tight connection. Now the shutoff device needs to be opened behind the receptacle and defueling can begin. The plastic thermal covering protects service technicians hands against frostbite.

Moreover, the defueling nozzles TK6 CNG for passenger cars and TK21 CNG for buses and trucks are available for defueling CNG tanks within vehicles. Defueling takes place via the vehicle s fueling connection. The defueling nozzle is attached to the receptacle, the opening spindle is turned until it stops and the receptacle is pushed open. Now the fuel tanks can be emptied via the medium outlet at the side. For more information, please visit the company s website www.weh.com

http://www.ngvjournal.com/s1-news/c5-products/new-weh-defueling-nozzles-available-for-discharging-cng-tanks/?utm_source=emBlue&utm_medium=email&utm_campaign=INTEGRADOR&utm_content=NewsEN__201802271402--News%20of%20the%20day&utm_term=NewsEN--4--none--50-60--ENVIO%20SIMPLE

[johnm]

How does this work (defueling) when the vehicle has a check valve after the fueling connection..