Home Research For Teachers HISTORY
Level 1
Level 2
Level 3
PRINCIPLES
Level 1
Level 2
Level 3
CAREER
Level 1
Level 2
Level 3
Search Hot Links What's New!
Gallery Feedback Admin/Tools

Please let me remind all of you--this material is copyrighted. Though partially funded by NASA, it is still a private site. Therefore, before using our materials in any form, electronic or otherwise, you need to ask permission.
There are two ways to browse the site: (1) use the search button above to find specific materials using keywords; or,
(2) go to specific headings like history, principles or careers at specific levels above and click on the button. 
Teachers may go directly to the Teachers' Guide from the For Teachers button above or site browse as in (1) and  (2).

FAQnewred.gif (906 bytes)          

Section 1.7 - Pressurized Reservoirs

hrule_bl.gif (260 bytes)

 

Douglas Pressurized Reservoirs

hydro008.gif (3872 bytes) hydro009.gif (3632 bytes)

Here are two examples of the Douglass Pressurized Reservoir. In (A), a low pressure is created by the Venturi action of flowing oil. This would cause air to come in through pipe (1) to relieve the low pressure; and a pressure head would be formed. The relief valve on the vent at the top of the tank would regulate the pressure. In (B), the spring load and piston keep oil under constant pressure. This type of design is bad because you couldn’t fill the reservoir with oil easily.

Boot Strap (self-pressurizing) Reservoirs

Boot Strap reservoirs are used in spacecraft and are used to maintain positive pressure in the hydraulic lines. Actually, there is some return line back pressure since P2 is greater than the return line pressure. For example, if the pressure line is at 500 psi and it acts on the 1 square inch piston surface (see figure below), the force generated would be 500 lb. Since the boot strap system incorporates piston 1 and piston 2 into a combined piston (see Pascal's Theory --Section 1.2), this force would be converted into a pressure, P2, of 5 psi acting on the 100 square inch surface of the piston, A2 .

hydro010.gif (5374 bytes)

This type of reservoir is very difficult to maintain. Also, bubbles trapped within this system cannot be removed very easily. Its good points are that it is foamless and has no air which can be trapped in the fluid due to its operation.


Send all comments to allstar@fiu.edu
1995-2017 ALLSTAR Network. All rights reserved worldwide.

Funded in part by

Updated: March 12, 2004