FIGURE IT OUT
PUBLISHER Innovative Designs & Publishing, Inc. 3245 Freemansburg Avenue, Palmer, PA 18045-7118 Tel: 800-730-5904 or 610-923-0380 Fax: 610-923-0390 • Email: Art@FluidPowerJournal.com www.FluidPowerJournal.com Founders: Paul and Lisa Prass Associate Publisher: Bob McKinney Editor: Michael Degan Technical Editor: Dan Helgerson, CFPAI/AJPP, CFPS, CFPECS, CFPSD, CFPMT, CFPCC - CFPSOS LLC Director of Creative Services: Erica Montes Account Executive: Norma Abrunzo Accounting: Donna Bachman, Sarah Varano Circulation Manager: Andrea Karges INTERNATIONAL FLUID POWER SOCIETY 1930 East Marlton Pike, Suite A-2, Cherry Hill, NJ 08003-2141 Tel: 856-489-8983 • Fax: 856-424-9248 Email: AskUs@ifps.org • Web: www.ifps.org 2021 BOARD OF DIRECTORS President: Rocky Phoenix, CFPMMH - Open Loop Energy, Inc. Immediate Past President: Jeff Kenney, CFPMHM, CFPIHM, CFPMHT - Dover Hydraulics South First Vice President: Denis Poirier, Jr., CFPAI/AJPP, CFPHS, CFPIHM, CFPCC - Eaton Corporation Treasurer: Jeff Hodges, CFPAI/AJPP, CFPMHM - Altec Industries, Inc. Vice President Certification: James O’Halek, CFPAI/AJPP, CFPMIP, CMPMM - The Boeing Company Vice President Marketing: Scott Sardina, PE, CFPAI, CFPHS Waterclock Engineering Vice President Education: Randy Bobbitt, CFPAI, CFPHS Danfoss Power Solutions Vice President Membership: John Bibaeff, PE, CFPAI, CFPE, CFPS DIRECTORS-AT-LARGE Chauntelle Baughman, CFPHS - OneHydraulics, Inc. Stephen Blazer, CFPE, CFPS, CFPMHM, CFPIHT, CFPMHT Altec Industries, Inc. Randy Bobbitt, CFPAI, CFPHS - Danfoss Power Solutions Steve Bogush, CFPAI/AJPP, CFPHS, CFPIHM - Poclain Hydraulics Cary Boozer, PE, CFPE - Motion Industries, Inc. Lisa DeBenedetto, CFPS - GS Global Resources Daniel Fernandes, CFPECS, CFPS - Sun Hydraulics Brandon Gustafson, PE, CFPE, CFPS, CFPIHT, CFPMHM - Graco, Inc. Garrett Hoisington, CFPAI/AJPP, CFPS, CFPMHM Open Loop Energy Brian Kenoyer, CFPHS - Five Landis Corp. Jon Rhodes, CFPAI, CFPS, CFPECS - CFC Industrial Training Mohaned Shahin, CFPS - Parker Hannifin Randy Smith, CFPHS - Northrop Grumman Corp. EXECUTIVE DIRECTOR (EX-OFFICIO) Donna Pollander, ACA HONORARY DIRECTORS (EX-OFFICIO) Paul Prass, Fluid Power Journal Liz Rehfus, CFPE, CFPS Robert Sheaf, CFPAI/AJPP, CFC Industrial Training IFPS STAFF Executive Director: Donna Pollander, ACA Communications Director: Adele Kayser Technical Director: Thomas Blansett, CFPS, CFPAI Assistant Director: Stephanie Coleman Certification Coordinator: Kyle Pollander Bookkeeper: Diane McMahon Administrative Assistant: Beth Borodziuk
Fluid Power Journal (ISSN# 1073-7898) is the official publication of the International Fluid Power Society published monthly with four supplemental issues, including a Systems Integrator Directory, OffHighway Suppliers Directory, Tech Directory, and Manufacturers Directory, by Innovative Designs & Publishing, Inc., 3245 Freemansburg Avenue, Palmer, PA 18045-7118. All Rights Reserved. Reproduction in whole or in part of any material in this publication is acceptable with credit. Publishers assume no liability for any information published. We reserve the right to accept or reject all advertising material and will not guarantee the return or safety of unsolicited art, photographs, or manuscripts.
WWW.IFPS.ORG • WWW.FLUIDPOWERJOURNAL.COM
New Problem
Valve Flaw Leads to Faulty Pressures By Robert Sheaf, CFPAI/AJPP, CFPE, CFPS, CFPECS, CFPMT, CFPMIP, CFPMMH, CFPMIH, CFPMM CFC Industrial Training
»
THE CIRCUIT BELOW was working for several years when the pressure-reducing valve on the clamp cylinder started leaking oil into an assembly bolt cavity. It appeared that a casting flaw finally failed after thousands of pressure cycles. The company purchased and installed a new module. However, the cap end would see full system pressure crushing the product while the rod side pressure would see reduced pressure as designed. Maintenance returned the valve and replaced it with a new one, but it had the same problem. They examined the old valve and confirmed the new ones had the same model number as the failed one. What was the problem?
Solution to the September 2021 problem:
Regenerative Circuit Drops Out
The regen circuit that did not work properly until the hinged fixture arm was about halfway up was caused by the spring drain line connected internally. Any pressure in the spring chamber of pressure controls is additive to the valve’s pressure setting. The pressure needed to lift the hinged fixture continually decreased as the fixture was raised. Externally draining the rod side counterbalance valve solved the problem. To view previous problems, visit www. fluidpowerjournal.com/figure-it-out.
M
Robert Sheaf has more than 45 years troubleshooting, training, and consulting in the fluid power field. Email rjsheaf@cfc-solar.com or visit his website at www.cfcindustrialtraining.com.
OCTOBER 2021
5
