Insane Hydraulics
Bold and audacious blog about fluid power
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Three Relief-Valve-Related Tips. (Inlcudes an unsafe tip, that can only be used by skilled and experienced techs, and an example of surprisingly efficient "redneck engineering").
What is Happening With the Hands-on Workforce in the Fluid Power Industry?
Since probably not all hydraulic techs are used to working with drilling systems and rod-breaking arrangements, I thought it would be a nice story to share - Drilling Head Motor That Was Turning Only in One Direction. (This post includes a link to another troubleshooting story that you may find useful, if you repair and test bent-axis hydraulic motors - Rexroth A6VM355 - Bulgarian Ventures and Hydraulic Motor Tests).
A question: Barrels and Shafts - Do You Know What Drives What?
Two Main Limitations of An Infrared Thermometer.
Today I continue the "investigation" of the A10VO100 pump that dumps about 20 liters per minute into the casing even after the complete replacement of the rotary group - Leakage of Rexroth A10VO DFR Controller.
DIY Extractor For Pulling Bushings Out of Blind Bores
I wanted to find out how much the bias servo-cylinder, which is always connected to the pump outlet, adds to the case drain flow in a Rexroth A10VO100 hydraulic pump. I was also wondering if the noticeable wear mark on the sealing surface of the piston shoe would add much to the leakage. Surprisingly, the leakage is extremely small. Even for the heavily marked shoe. Details (and a video) can be found here - Evaluating Leakage of a Rexroth A10VO100 Bias Servo-Cylinder
I created this blog because I like hydraulics and because I believe that sharing knowledge is important. But after having run it for a while, I feel that it is almost like a journal for me. Looking through my older posts brings back memories and makes me realize how fast time flies. Today I am republishing a blog post that I wrote when I got back from my trip to Africa in 2011. I'm so glad I wrote it fresh off the plane - because it captured the state of the mind of a young tech returning from such an interesting adventure. I am sure that some things are different there now, and some are probably still the same. In any case - I enjoyed getting back to it, and I invite you to have a glimpse of what fixing hydraulic equipment in Africa was like eleven years ago - Hydraulic Battles in Guinea Bissau.
The First Three Things I Need to Know About a Hydraulic Shop to Tell if It's Any Good
Another timeless battlefield story today, with five valuable lessons at the end - Inventing A New Load Sensing Valve.
The Best Tool In The Arsenal Of a Hydraulic Technician
Three Common Filter-Related Misconceptions.
I have to admit that I got carried away with this one. I sat down to write a simple one-page post about the viscosity of hydraulic oil, then one thing lead to another and... well, let's say that if you do get to the end of it, you'll never have to ask how kinematic viscosity is different from absolute, and why air is more viscous than water, and what all these centistokes really mean. It's a lot of typing for a single evening, so you may find some errors or typos - I'll try to clear them out during the week. So, without further ado - I present to you - Absolute vs Kinematic Viscosity of Hydralic Oil.
About the o-ring leakage from last week. I tried cold contacting SUN folks, and I made a post on LinkedIn describing the failure and the test I ran to recreate it, and asking if anyone could explain the mechanics behind "o-rings working as pumps", but unfortunately I have zero news so far. I'll keep waiting... And today's post is about the time when a hydraulic tech wants to shoot the piece of machinery in front of him. Literally. An old troubleshooting story about an Inexplicable Malfunction of a 1210B Forwarder Hydrostatic Transmission.
Results of my attempts to recreate Interface Leakage Caused By O-rings Working as Pumps.
Two older articles get a "facelift" today (and the https): Evaluating Drain Flow With The Five Plus Five Rule and Quick Couplings in Hydraulic Motor Drain Lines. (Don't forget to press reload if you read them before).
A couple of days ago I was asked to troubleshoot a Danfoss PVG32 DCV that "wouldn't work for some reason", and boy did that bring back a lot of memories! "Dude, it won't work!" - is the key phrase of today's post about Getting Those Hydraulic Knowledge Nuggets.
If You Use O-rings Every Day...
The library is expanded with the Interactive Standard O-ring Size Table. I'll explain the motivation and talk on the subject of o-rings next week - putting all the data dogether took more than I expected...
An interesting pump control solution in Rexroth A7VO55LR3E Open Loop Pump
I've been working non-stop doing the annual maintenance at our mine for the last two weeks. Luckily the production is to start tomorrow, so I should be "officially free" pretty soon. I am writing this post as I am waiting for the green light for re-commissioning the stuff that I serviced, and I apologize if my latest posts sound like a rant of a person dead on his feet... I also wanted to share some pics from this stretch, so here it is: More On Pressure Filters and Hose Replacement.
Rant on Danfoss PVE Series 7 Electrohydraulic Actuators and Their Marking.
Danfoss PVEH Electrohydraulic Actuator - What's Inside? (Includes a free tip on how you can fix a "broken" actuator).
If you want to see what a blocked NFC pilot orifice looks like, check out today's post about A Common Malfunction of Negative Flow Control Systems