cptkent

Pneumatic hose maximum length

Recommended Posts

Posted (edited)

Hi,

Can someone please tell me if there is a practical maximum hose length for a Lego pneumatic system?

The application I have in mind is for ‘remote switching’ of a railway track point. The track point is ~1500mm from where I want the switch.

I presume I would be best to use 3rd party hose at these lengths.

I’ve tried to search for an answer, but nothing has turned up. Can anybody here help?

thanks

david

edit: ps, I am probably going electrical, but just thought I’d consider a pneumatic solution, though it appears in any case parts for that may be difficult to source.

Edited by cptkent
Addition

Share this post


Link to post
Share on other sites
Posted (edited)

There is probably a limit, but I don't think you'll be hitting it at 1.5 meters. Electrical should be easier to implement, though.

Edit: Tried it, had no problems.

Edited by Saberwing40k

Share this post


Link to post
Share on other sites
3 hours ago, cptkent said:

Hi,

Can someone please tell me if there is a practical maximum hose length for a Lego pneumatic system?

The application I have in mind is for ‘remote switching’ of a railway track point. The track point is ~1500mm from where I want the switch.

I presume I would be best to use 3rd party hose at these lengths.

I’ve tried to search for an answer, but nothing has turned up. Can anybody here help?

thanks

david

edit: ps, I am probably going electrical, but just thought I’d consider a pneumatic solution, though it appears in any case parts for that may be difficult to source.

 No problem. A long tube is just like an air tank. The only thing... the longer the tube the more air in the system, and less contol over the piston

 

Share this post


Link to post
Share on other sites
45 minutes ago, ben20 said:

No problem. A long tube is just like an air tank.

Exactly.

A longer tube only changes the dynamic behaviour of your system.

Waiting long enough, the pressure on your pistons is the same as with short tubes.

The main difference comes from the dynamic resistance a long tube has, so your system will react slower. Also, the elasticity of the tube means that you will need slightly more air for the same movement as the tube will expand with pressure.

 

If you switch early enough, you shouldn't have any problems :-)

Share this post


Link to post
Share on other sites

There have been alot of pneumatically powered cars out there in the past.  I also build and drove a pneumatically powered Unimog which required about 5 feet of hose (more or less the same amount you are proposing).  The hose was not an issue.  And whatever delay there was supposed to be was more or less negligible.....

Share this post


Link to post
Share on other sites
17 hours ago, ben20 said:

 No problem. A long tube is just like an air tank. The only thing... the longer the tube the more air in the system, and less control over the piston

+1

Share this post


Link to post
Share on other sites

A long electrical wire may also have its own issues. The wire gauge TLG uses is so small that voltage drop may result in less power for the motor as power is wasted through what is essentially a long, thin heating element. 

Share this post


Link to post
Share on other sites

Thanks to all those who replied.

I have a couple of 'electrical' solutions, but then started wondering about a pneumatic one. I may set up a testbed to evaluate it.

David

Share this post


Link to post
Share on other sites

I just tried the 10 foot piece of 3rd party tubing on my desk.  I used a small pump, and it was just like having a tank in the system.  Slow but worked perfectly.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.