Mechanism Ideas for: Rotary Action-input Pump?

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Discussion Overview

The discussion revolves around designing a handheld pump intended to extract diesel from a car's fuel tank, focusing on mechanisms that convert rotary action into suction force. Participants explore various design ideas, existing solutions, and challenges related to the operation and efficiency of such pumps.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant expresses uncertainty about how to create a mechanism that transforms rotary action into suction force, mentioning elements like shafts, cams, and gears.
  • Another participant suggests looking at existing hand pump designs instead of creating a new one from scratch.
  • A participant identifies the application as a diesel lift pump and describes how it typically converts rotary motion into reciprocal motion.
  • One participant highlights the importance of priming the pump and suggests that a peristaltic pump might be an easier design to implement.
  • Links to various resources and existing pump designs are provided for further exploration.
  • Another participant notes the challenges of designing a pump compared to purchasing existing models, emphasizing the complexities of sealing and priming.
  • A separate inquiry about modern hand water pump designs and their components is introduced, seeking online resources for detailed specifications.

Areas of Agreement / Disagreement

Participants do not reach a consensus on a specific design approach, with multiple competing views on whether to create a new pump or utilize existing designs. The discussion remains unresolved regarding the optimal mechanism for achieving the desired suction force.

Contextual Notes

Participants express varying levels of understanding regarding the mechanics involved, and there are references to specific challenges such as air bleeding in pumps and the need for effective sealing. The discussion also touches on the economic considerations of designing versus purchasing a pump.

Who May Find This Useful

This discussion may be useful for individuals interested in mechanical design, pump mechanisms, and those exploring DIY solutions for fuel extraction systems.

Al-Layth
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TL;DR
Problem:
Converting Rotary motion -> Suction force

For the objective of pulling up liquid through a pipe
I'm trying to come up with a design for a handheld pump that will be used to suck diesel from a car's fuel tank. There's definitely going to be a pipe dipping into the fuel tank, and there's definitely going to be a human manually operating the pump.

I'm trying to think of a mechanism that would transform rotary action input, (like a rotatable lever) into suction force that would pull the diesel in the fuel tank into the pipe. But I can't think of anything lol. The main problem is I don't understand what kind of motion is needed to provide a suction force through the pipe so right now I am just thinking through mechanism elements like shafts, cams and gears with no end goal in sight

Any ideas? TYSM
 
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No need to reinvent the wheel. There are many, many, many hand pumps in existence. Take a look at a few designs.
 
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Al-Layth said:
I'm trying to think of a mechanism that would transform rotary action input
Why?
 
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The application you described is called a diesel lift pump. There are may designs, some mechanical, some electrical. You can almost visualize how it converts rotary motion into reciprocal motion in the picture below. It has a lever attached to a wire used to manually operate the pump. That is used to purge air from the pipes before cranking the engine.

1663416176764.png
 
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Al-Layth said:
... I'm trying to think of a mechanism that would transform rotary action input, (like a rotatable lever) into suction force that would pull the diesel in the fuel tank into the pipe. But I can't think of anything lol. The main problem is I don't understand what kind of motion is needed to provide a suction force through the pipe ...
Welcome!
First, the air contained in the pipe must be sucked by the pump, then the liquid will be pushed up by the atmospheric pressure.
I recommend you researching positive displacement rotary pumps.

Please, see:
https://en.m.wikipedia.org/wiki/Pump#Positive-displacement_pumps

 
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Priming the pump will be the difficult part, because gear and vane pumps may bleed too much air through the sliding clearances, or shaft seals. The easiest rotary hand pump to make yourself would probably be a peristaltic pump using a single long silicone or rubber tube that starts in the tank, pumps, and delivers the fuel to its destination.
https://en.m.wikipedia.org/wiki/Peristaltic_pump
 
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Al-Layth said:
I'm trying to come up with a design for a handheld pump that will be used to suck diesel from a car's fuel tank.
In the US, it's common to see pickup trucks with fuel tanks in the box. Those tanks have hand pumps mounted that look like some of the pumps linked in Post #7. Those pumps cost less than it would cost to design and build your own pump. And the manufacturers of those pumps have solved the problems of priming and sealing that make designing your own pump a far more challenging project than you would expect.

I know that diesel fuel in, say London, is about $8.00 US per gallon vs "only" $5.00 US in the US, but I really hope that you are not planning to suck expensive fuel from other people's fuel tanks to put in your fuel tank. :smile:
 
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Two thread starts merged into one
I am looking for the designs of various models of modern hand water pumps, specifically the parts used and the dimensions of those parts. Manufacturing and assembly processes are welcome too. Does anyone know of such an online resource. I tried googling but did not find anything so I beseech thee.
 
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Al-Layth said:
Summary: Is there an online archive of modern hand water pump models and their parts

I tried googling but did not find anything
Did you already read through the Wikipedia article and its References/Links?

https://en.wikipedia.org/wiki/Hand_pump
 
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