Can vapor line on truck be used for filling?

• Sep 16, 2021

• #2

pierreick

Chemical

Nov 20, 2005

1,289

Hi,
Can you describe better your unloading process , transfer from truck to storage tank ! a sketch is welcome with the main equipment?
note : what is the material ?
Pierre

 

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• Sep 16, 2021

• #3

LittleInch

Petroleum

Mar 27, 2013

21,545

Do you not have sealing valves on the end of the hose?

I can't work out what you mean.

Needs a diagram and some more explanation.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

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• Sep 16, 2021

• #4

jari001

Chemical

Aug 9, 2013

478

I would also think you need the approval from the chemical supply company if you're going to do something non-standard activity with their truck?

 

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• Sep 16, 2021

• #5

Latexman

Chemical

Sep 24, 2003

6,928

Why does the hose still have some chemical in it? That's the problem; solve that. We need a dimensional drawing with elevations to help you. A picture or three might help. What's the chemical?

Good Luck,
Latexman

 

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• Sep 16, 2021

• Thread starter
• #6

molebleeze

Mechanical

Aug 25, 2015

8

Hi all, see attached picture, hopefully I make it reasonable.
The liquid needs constant temperature control, so the unloading pump is also used as circulation pump. We connect the hose to the truck liquid port and vapor hose to the vapor return port.
At the end of the unloading, the pump will not be able to suck completely dry the hose (it is a centrifugal pump). Therefore, the hose still has some liquid in it. We don't like the liquid stay in the hose. So would like to connect the hose to the vapor port of the truck and use the air blow to push the liquid in the hose back to the truck. [URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1631805434/tips/New_Bitmap_Image_2_nf23ia.bmp[/url]

 

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• Sep 16, 2021

• #7

Latexman

Chemical

Sep 24, 2003

6,928

I doubt the sketch represents elevations too accurately. Is the pump in a flooded suction or a suction lift situation (when the truck just runs dry)?

Good Luck,
Latexman

 

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• Sep 16, 2021

• Thread starter
• #8

molebleeze

Mechanical

Aug 25, 2015

8

It's a self priming centrifugal pump and is about 1 ft elevation below the truck. However, it just can't completely strip the hose and the unloading line.

 

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• Sep 16, 2021

• #9

Latexman

Chemical

Sep 24, 2003

6,928

Sounds like it's loosing prime when the head gets so low. Is the liquid at or near it's normal boiling point, or has some dissolved gases in it?

This would be easier if you'd tell us what the pumpage is.

As you can tell, I'm not inclined to pressure push anything until the problem is well understood.

Good Luck,
Latexman

 

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• Sep 16, 2021

• Thread starter
• #10

molebleeze

Mechanical

Aug 25, 2015

8

It is pumping liquid with properties close to water.

 

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• Sep 16, 2021

• #11

3DDave

Aerospace

May 23, 2013

10,767

If the tank is already vented then you have nearly 15 psi / 1bar to force liquid up. If that's not enough then how will adding more pressure help?

 

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• Sep 16, 2021

• #12

Latexman

Chemical

Sep 24, 2003

6,928

Could the vapor return line be too small, allowing some vacuum to build in the tanker and some pressure to build in the tank? That could explain the issue.

If this has been developing/getting worse over time, can the vapor return line be plugging?

Good Luck,
Latexman

 

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• Sep 16, 2021

• #13

pierreick

Chemical

Nov 20, 2005

1,289

Hi ,
Is it a new problem ?
Is the recirculation line in service during unloading?
You should talk to your chemical supplier about the best way to unload this type of chemical, they should have a lot of experience .
Is the technology of the pump the right one ? ,
You may lose the priming when the level is too low !
Do you have possibility to elevate the truck to add height to the suction , let say use a movable deck ?
Can you transfer under pressure instead of using a pump .

Again better to talk to someone familiar with your product and knowledgeable about unloading this chemical.
My view.
Pierre

 

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• Sep 16, 2021

• #14

Compositepro

Chemical

Oct 22, 2003

7,760

You can use a small pump of a different style to remove residual fluid from the lowest point at the hose. An air operated double-diaphragm pump (AODD) is very well suited to this type of use.

Using compressed air to blow liquid uphill into a truck involves a number of well-known serious hazards.

 

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