Keeping propane flowing in cold temperatures

[bigjim]

11 hours ago, Ray,IN said:

Forktrucks run on liquid propane only. Appliances use vaporized propane, the cylinder/tank valving must be above the liquid level. High output appliance burners consume propane faster than it can vaporize in containers with a small diameter during cold weather.

Actually with the nudge for my memory I remember this to be true.  I can not remember if vehicle conversions to be able to use gasoline of propane utilizing a horizontal tank in the bed runs on liquid or gas.  Also propane powered farm tractors are they running liquid or vapor?

[Darryl&Rita]

27 minutes ago, bigjim said:

Actually with the nudge for my memory I remember this to be true.  I can not remember if vehicle conversions to be able to use gasoline of propane utilizing a horizontal tank in the bed runs on liquid or gas.  Also propane powered farm tractors are they running liquid or vapor?

Liquid fed. They have an atomizer to create vapour closer to the mixer (carburetor). The atomizer is heated by engine coolant, allowing for winter operation, without running lean due to tank pressure.

[noteven]

I ran a '77 GMC pickup with an Impco carburetion system on straight propane for 240,000 (trouble free) miles.  Clean oil and a non solvent fuel makes a difference. Automotive systems use liquid from the tank to engine for reason Darryl said.  Cars, trucks, forklifts, ag tractors etc

Stationary gas engines like generators, oil well pump engines, pipeline compressor engines -  can run on vapor supply due to more constant power settings...

Like a furnace... constant output

 

[Star Dreamer]

On 10/30/2020 at 7:22 PM, Ray,IN said:

The small surface area is the problem LP only vaporizes at the surface of the liquid form, which is why larger horizontal tanks are preferred.

But larger horizontal tanks have their issues. One is space for them usually have to be located under the floor in the frame area. 

Two, they add a lot of extra weight, but maybe not as much as having multiple vertical tanks.

Three, to refill, either we have to bring the trailer to a propane place or have them come out to a campground. With smaller tanks, 20# ones I can pick up at any gas station or Walmart and can carry spares. 30# ones fit it the back of the smart so I can run them to a local propane place. 

 

I will probably try a tank  heater next. I was surprised that they are set to go to 90-100 degrees F temperature so tanks must really like it warm.

[Ray,IN]

2 hours ago, Star Dreamer said:

But larger horizontal tanks have their issues. One is space for them usually have to be located under the floor in the frame area. 

Two, they add a lot of extra weight, but maybe not as much as having multiple vertical tanks.

Three, to refill, either we have to bring the trailer to a propane place or have them come out to a campground. With smaller tanks, 20# ones I can pick up at any gas station or Walmart and can carry spares. 30# ones fit it the back of the smart so I can run them to a local propane place. 

 

I will probably try a tank  heater next. I was surprised that they are set to go to 90-100 degrees F temperature so tanks must really like it warm.

The heat compensates for the lack of vaporization surface area. There is o right or wrong, it's simply a matter of physics.

I think I posted a link to the engineringtoolbox.com previously, here is the most relevant (Bottom)chart from that website:

[bigjim]

Thinking about this more the conversions I believe used liquid up to a regulator under the hood near the modified carb so it seems in my weak memory at that point it was operating off vapor.????

Where I did delivery in mostly rural areas being less than 600ft altitude a fair number of farmers used propane tractor in the mid to low size.  They were willing to sacrifice a smallish power loss for the longevity and some what less maint.  Most of the serious farmers had their own 250gal tank built as a trailer. (not on a trailer)  So at times I would do a delivery to whatever area they were working in.  As Ilved in a rural area there with closest neighbor 1/4 mile some would leave there tanks in my barnyard for me to fill as I often had the truck at home.  I really liked this job but the pay was just not enough with the size family and crazy wife I had.  Also even though I liked the people at the company and the company in general their training was minimal at best I came to realize their operation was frequently unsafe.  At first I was ignorant and did not know the difference.  My second week on the job I had a delivery truck catch fire under the hood at the edge of Terrell, Tx

[rynosback]

On 10/31/2020 at 8:23 AM, Dutch_12078 said:

Make sure it's a weatherproof heating pad unless your cylinders are enclosed.

I agree, my 2 x 40 lbs cylinders are in a compartment in the rig. 

[Wrknrvr]

   I am curious if at low temperatures, does the actual boiling of propane, make the liquid colder in the tank, than the outside air temperature.

 

 Just thinking,    Vern in a T-shirt 

Edited November 4, 2020 by Wrknrvr

[Dutch_12078]

3 minutes ago, Wrknrvr said:

   I am curious if at low temperatures, does the actual boiling of propane to make the liquid colder in the tank, than the outside air temperature.

 Just thinking,    Vern in a T-shirt 

Yes it does. At upper 30's F I often see frost or ice on the side of my active cylinder up to the liquid level. One of the low cost level gauges is a plastic strip with a temperature sensitive coating that's attached to the cylinder and uses the temperature difference between the liquid and gas to as the level indicator. The cylinder does have to be in active use for it to work though.