4" Hose Support System 1

[jerfy]

Hello,

I am trying to replace a stiff arm we use to offload fuel from a truck with a hose system for flexibility reasons. The arm currently supports itself, meaning the drivers don't do much lifting of the arm, just swiveling. I expect this hose to be rather heavy at any given time and don't want drivers lifting it without support.

Is there a precedent for this already? Using Google I found a solution using a typical retractable hose reel but this doesn't help with attaching the heavy hose end to the truck.

Besides what Google said, my idea was to design some pulley-hangar system that is able to support the hose on a swivel similar to the arm we have now. The fixed pulley holds the end of the hose up and is able to swivel freely. I've only sketched some designs but am wondering if this is viable or if it already exists somewhere?

Thanks a bunch

 

[MikeHalloran]

The word you need to remember is 'festoon':

https://www.google.com/search?q=festooning+system+for+hose&ie=utf-8&oe=utf-8

Mike Halloran
Pembroke Pines, FL, USA

 

[tbuelna]

If the 4" fuel hose has a long length, and the nozzle must be positioned with some accuracy both horizontally and vertically when being attached to the mating tank receptacle, then you'll likely need both a swing arm support and a cable balance system (or something similar) at the hose end. A 4" fuel hose is stiffer than you would imagine, and would be very hard to handle. I think OSHA regulations limit the amount of physical effort required from a single worker to perform their job to less than 40lbs.

 

[MikeHalloran]

Tbuelna's excellent comments probably explain why the current boom is articulated/rigid.

Maybe you just need to rebuild the joints...

Mike Halloran
Pembroke Pines, FL, USA

 

[tbuelna]

Festooning!

I though MikeHalloran was having a bit of fun with his post so I did not bother to check the link. I was not familiar with that word in engineering terms, and had only heard it used to describe the extravagant floral decorations on hats my crazy aunt liked to wear. But by golly, it turns out "festooning" is a legitimate engineering term. So I learned something new from this thread!

Now if I can only find an excuse to use "festooning" in some technical document.

 

[jerfy]

Thanks a bunch,

I researched "festoons" and made a few calls to distributors who confirmed my initial suspicion that festoons won't support the size hose we need (4 inch diameter). As stated, it seems these are for more flexible hoses. So, I am back to the drawing board.

If a 4 inch hose is too large/stiff to handle, then how do other facilities offload trucks? From our research it seems as though many facilities use hoses to offload fuel and use stiff loading arms to load fuel. How do these places manage the hose weight?

 

[tbuelna]

jerfy- More details about your particular situation (such as a rough sketch with a couple dimensions) would be very helpful. Below is a picture of how bulk fuel is commonly offloaded from tanker trucks.

 

[MikeHalloran]

Ar The Skunk Works, we maintenance mechanics would check that the contents had been analyzed and approved, then hard plumb the tank car drains into the system with iron pipe. Then come back the next day to undo the pipe and get the next car moved into position. Trucks are smaller and take less time to unload.



Mike Halloran
Pembroke Pines, FL, USA

 

[jerfy]

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1438268897/tips/HoseDrawing_byaxly.pdf[/url]

Thanks again,

Here is the sketch. The issue lies in the 12' support system we want to bury in the ground. The only part moved by the driver is the hose-truck connection, which is where we place the hose saddle. We are worried this is too heavy and requires support from an above cable system. The festoon is too small for the 4" hose. Is there any other precedent for this besides a festooning system? We'd rather not reinvent the wheel.

Additionally, i'm fresh out of college and new to the community as a whole. Is my sketch appropriate? Am I providing the correct details?

 

[MikeHalloran]

How about letting the hose slide around on a big ol' steel-topped table?


Mike Halloran
Pembroke Pines, FL, USA

 

[tbuelna]

Thanks for the sketch. It helps clarify things.

First, it appears the primary reason for the rotating support boom is to stow the hose/nozzle assembly well clear of where the tanker trailer needs to travel when docking. I'd imagine the fixed vertical support post itself would need to be located a couple feet clear of the side of any passing tanker, and protected with some of curbing or barrier. The vertical position of the discharge valve on the tanker trailer should be consistent on each vehicle. But the longitudinal/lateral position of the tanker trailer discharge valve will vary based on how good a job the driver does with parking.

The typical 4" fuel transfer hose weighs around 2-3 lbs/ft empty, and based on your sketch I'm assuming the 12ft transfer hose length is mostly empty when being attached. However, you should also consider that attaching the fuel nozzle to the mating connection on the tanker requires the two fittings to be fairly accurately aligned. If you look at the picture I posted above, you'll note that due to the stiffness of the hose this requires a fair amount of slack in the hose length.

 

[jerfy]

Several distributors have also commented on the stiffness of the hose. As stated, we're replacing a pipe and need the flexibility for exactly the reason tbuelna mentions, for easily aligning the two fittings. Would there even be a noticeable difference in flexibility between the pipe and the 4" hose? How can I determine how much slack we would need to see flexibility improvements?

 

[jerfy]

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1438357735/tips/FaunaOffloadSketch_m9ms9d.pdf[/url]

I have uploaded 2 more sketches both from top down viewpoint. They are out of order but the 2nd sketch shows our current system with offloading arm. It is hard to connect to the truck unless they know exactly where to park. The first sketch shows my idea for hose with swivel boom support. It also shows 2 theoretical positions of the hose 1 and 2. 1 is the case of the hose offloading from a truck with slack in the hose to allow flexibility in where the truck parks to connect and offload. 2 is the case of the hose resting but pulled taut away from the pump so that fuel can drain into the offload pump by gravity. My underlying questions are if the 4" hose will be as much improvement as we think in flexibility and if there is something we can buy that accomplishes the job of the boom support.

Thanks again,
Jeremy

 

[MikeHalloran]

It's time to make a proper to-scale layout/drawing.
You will probably find that the hose is stiff enough that you will have to work hard to bend it 90 degrees over its 12 foot length, which is pretty much how I suggest you draw it.

Mike Halloran
Pembroke Pines, FL, USA

 

[tbuelna]

jerfy-

I looked at the Goodyear catalog specs for their 4" fuel transfer hose. The catalog listed a 10" min bend radius for this hose at RT, but did not provide any stiffness values. The most obvious way to resolve the hose stiffness issue would be to simply make the hose longer. Is there some reason your hose length is limited to 12ft? Is there a requirement for your support system to prevent the hose from contacting the ground?

 

[jerfy]

tbulena: We are not specifically limited but I had considered the longer hose, the more bend. My initial design was something 12-15 feet based on no hose stiffness data. We can extend the hose, but we are offloading biodiesel, and the biodiesel compatible Teflon hoses get expensive fast. Also, the hose must be short enough to be held upwards and taut within the skid, as the biodiesel must gravity drain out when not in use. So in that sense, it can touch the ground if it still drains out.

MikeHalloran: I have been interested in learning how to do PIDs but the mechanical drawings are not something I learned in college. Do you have any recommendations for resources to learn this? Are these typically done by hand or on the computer?

Thanks again

 

[MikeHalloran]

You can start with a sheet of quadrille paper and a pencil if you like.

I'd expect any local community college to offer a course in drafting, or at least blueprint reading. I guess engineering schools don't bother to teach our lingua franca anymore, since high schools started teaching CAD. Damn shame, that.


Mike Halloran
Pembroke Pines, FL, USA

 

[tbuelna]

jerfy-

OK, so based on your last sketch the transfer hose section must empty itself by gravity alone after the discharge valve at the tanker is closed. Your sketch shows a 14" drop over 12ft which will drain properly using gravity, assuming the hose is vented and there are no low points in the hose length where fuel can collect.

Here are a couple other things to consider:

In California where I live, there are very strict emissions regulations even for the tiny amount of fuel vapor that might be released into the atmosphere during tanker transfers. The storage tanks are sealed and vented thru a vapor collection system, and the tanker must connect to this sealed system during offloading. The tankers must use fluid-tight dry-break connections for both the transfer and vent hoses. The transfer hoses, vent hoses, and tanker valve connections must be capped when not in use. And no spillage of liquid fuel or significant release of fuel vapor is permitted during offloading.

Another problem is water contamination of the fuel. If your fuel transfer system is exposed to environmental conditions like snow/rain/humidity, does your design provide adequate protection from moisture intrusion?

Here is a link to a typical Goodyear fuel transfer hose product:

http://www.goodyearrubberproducts.c...odyearIndustrialHoseCatalog1.Page163gpage.asp