Antique Engines and Old Iron
[Home] - [HELP] - [Forums] - [Library] - [Photo Gallery] - [Groups] - [Classified Ads] - [Subscribe] - [Links] - [Books] - [Sponsors] -

Go Back   SmokStak > SmokStak® Shop Equipment Tools and Techniques > Machine Shop and Tool Talk
Forgot Password? Join Us!

Notices

Machine Shop and Tool Talk Shop Equipment, fabrication, repairs, how to fix it, which tool to use for the job. Machinist shop talk, straight to the point.

Machine Shop and Tool Talk

DIY Waterjet Cutter


this thread has 16 replies and has been viewed 3267 times

Reply
 
Thread Tools Display Modes
  #11  
Old 06-02-2017, 04:40:29 AM
tdmidget tdmidget is offline
Registered-I
 
Join Date: Nov 2012
Location: Tucson, Arizona
Posts: 175
Thanks: 52
Thanked 57 Times in 47 Posts
Default Re: DIY Waterjet Cutter

Quote:
Originally Posted by I like oldstuff View Post
Dal, consider using a little pressure washer ~ 6-800 psi. Run that output into a strong cast iron gear pump and you'll have unlimited pressure. Relief valves definitely required!
Uh, no. The only pump that makes use of incoming pressure is the centrifugal pump. Positive pressure pumps cannot take advantage of incoming pressure. Ask a fire fighter engineer.
Reply With Quote
Sponsored Links
  #12  
Old 06-02-2017, 05:00:25 AM
Thaumaturge Thaumaturge is online now
Subscriber
 
Join Date: Mar 2014
Location: Beryl, Utah USA
Posts: 3,649
Thanks: 2,796
Thanked 3,673 Times in 1,542 Posts
Default Re: DIY Waterjet Cutter

Not so... the Cat high pressure pumps use staged pistons.
Doc
__________________
"The time has come," the Walrus said, "To talk of many things: Of shoes--and ships--and sealing-wax--Of cabbages--and kings"
Reply With Quote
  #13  
Old 06-02-2017, 08:53:47 AM
Odin Odin is offline
Subscriber
 
Join Date: Jun 2014
Location: Elmira, New York
Posts: 1,086
Thanks: 247
Thanked 805 Times in 435 Posts
Default Re: DIY Waterjet Cutter

Quote:
Originally Posted by tdmidget View Post
Uh, no. The only pump that makes use of incoming pressure is the centrifugal pump. Positive pressure pumps cannot take advantage of incoming pressure. Ask a fire fighter engineer.
I think it would depend on the geometries of the pump and what mechanism drives it.

A simple plunger pump will not pass on forward pressure, although said pressure will help it on the return stroke by making sure the check valves seal properly.

A balanced-pressure plunger pump, with water on both sides of the piston, will benefit from upstream pressure. The water behind the piston provides force to expel water as well as the pump rod pushing it along, and this can be achieved in both directions.


Gear type pumps probably can be constructed in a way that lets them boost pressure in stages, again by balancing the design so that the incoming pressure helps drive the output.

Which makes me wonder what kind of pump the fire department was using that couldn't boost pressure in this way. Probably a pump designed to operate with its intake at a vaccum lifting water from a pond into a truck.
Reply With Quote
  #14  
Old 06-02-2017, 08:58:20 AM
I like oldstuff I like oldstuff is offline
Subscriber
 
Join Date: Jan 2012
Location: Milwaukee, Wisconsin, USA
Posts: 5,141
Thanks: 1,140
Thanked 5,115 Times in 2,087 Posts
Default Re: DIY Waterjet Cutter

Quote:
Originally Posted by tdmidget View Post
Uh, no. The only pump that makes use of incoming pressure is the centrifugal pump. Positive pressure pumps cannot take advantage of incoming pressure. Ask a fire fighter engineer.
Good point. But an increase in input pressure even to a gear pump will help somewhat. Yeah technically a gear pump has losses from internal leaks therefore can't be considered positive displacement. +1 on the centrifugals benefiting from multiple stages such as a submersible well pump.
Reply With Quote
  #15  
Old 06-02-2017, 12:08:27 PM
akuna akuna is offline
Registered-III
 
Join Date: Jun 2012
Location: Central Oregon
Posts: 3,655
Thanks: 348
Thanked 1,311 Times in 982 Posts
Default Re: DIY Waterjet Cutter

All I know about pumps on fire fighting equipment is you do not want to pull a vacuum when connected to a hydrant.
Reply With Quote
  #16  
Old 06-02-2017, 12:25:57 PM
Power Power is offline
Registered-III
 
Join Date: Aug 2011
Location: New Jersey
Posts: 4,535
Thanks: 1,066
Thanked 2,595 Times in 1,529 Posts
Default Re: DIY Waterjet Cutter

That is to prevent damage to connected customer equipment.

Nearby municipalities do not have city water. Every residence has it's own well. When there is a fire, they come with a tanker truck, and then lay hoses to nearest pond or source of water. Often hundreds of feet away. I have seen inlet pressure gauges showing substantial vacuum.
Reply With Quote
  #17  
Old 07-04-2017, 12:23:42 AM
WidgetAU WidgetAU is offline
Registered
 
Join Date: Jul 2017
Location: Pearce, Australian Capital Territory, Australia
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Default Re: DIY Waterjet Cutter

Hi All

noob user questions on there way

watched the video and read the posts, and have been looking at a lot of waterjet sites and found that there is a lot our there for the pros, but not a lot for the low budget hobbyist

thinking

Pump

Will this have enough pressure/flow to be of any use?

Mach3 USB 3 Axis CNC Motion Control Card

Has anyone used Mach3 to control a waterjet?

if the pump is up to the task what nozzle (mixer?) would suit?

this is for "desktop" hobby use, so speed is less important than cheap

more questions to follow I am sure
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

F o r u m Jump

Similar Threads Chosen at Random
Thread Thread Starter F o r u m Replies Last Post
New Day Cutter 41Briggs Maytag Engine Collectibles 1 10-05-2014 11:25:06 PM
Sickle Bar Cutter IronworkerFXR Antique Farm Tractors 8 09-16-2014 12:11:15 AM
Bone Cutter oldironlindy Farm + Industrial Antiques and Collectibles 10 12-07-2011 06:16:16 PM
brush cutter keith york Antique Engine Archives 2 04-22-2003 08:18:45 AM


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 06:46:54 AM.

Smokstak and Enginads site search!


All use is subject to our TERMS OF SERVICE
SMOKSTAK® is a Registered Trade Mark - A Community of Antique Engine Enthusiasts
Copyright © 2000 - 2016 by Harry Matthews P.O. Box 5612 - Sarasota, FL 34277