Insane Hydraulics
Bold and audacious blog about fluid power
As you might imagine, I've already reached the point where I can allow myself declarations of a certain level of "hydraulic authority", and can pull from under my belt hundreds of victorious battles against all sorts of hydraulic contraptions, such as presses, lifts, cranes, belts, winches, platforms, breakers, crushers, excavators, backhoes, handlers, graders, loaders, dumpers, haulers, tractors, foresters, core drilling rigs, raise boring rigs, ahh... you-name-them-rigs... - you get the picture, right? Furthermore, I'm in constant contact with numerous in-house maintenance crews of our clients, so you can trust me when I say I know a little something about how hydraulic troubleshooting is usually done, and a little something about how it should be done, too.
And this is why I feel pretty confident when I say that whenever you troubleshoot a piece of hydraulic equipment (after you've performed the 'preliminaries' and confirmed that the "simple stuff" is "in the green", and that this time it's not the operator leaning against an emergency stop button) - in 100 cases out of 100 you will need to measure one or several of the following parameters:
Pressure. And very often it is necessary to read pressures in multiple points at the same time.
Flow. When a system can't be diagnosed or adjusted with pressure readings alone, you'll need to take out the "big guns", and begin impressing the "audience" with your flow-measuring gear.
Current and Voltage. Because it's never "just the oil" these days. E.g. - when a solenoid current and/or voltage needs to be measured in order to confirm if a component is behaving properly, or an industrial analogue signal (e.g. 4...20 ma) must be checked to verify if an input is correct.
Temperature. This is an important one, because incorrect temperature is a sure sign of a malfunction in a hydraulic system.
Speed. Depending on the equipment it can be hydraulic motor or prime mover rotation speed, linear actuator speed, actual speed of a vehicle, also - unit-less values that define operation speed, like cycles per minute, tons per hour, etc...
I am lucky to have all sorts of test gear at my disposal - analogue pressure gauges, digital pressure gauges, several ranges of flow meters and pressure sensors combined with multi channel data loggers, infra-red and contact thermometers, optical and direct tachometers, surface-speed meters, multi-meters - the best stuff money can buy. You name it - we've got it!
Then - what is the problem?
Well, my two biggest issues, especially in the filed, have always been caused by the fact that whenever I use all these wonderful (and extremely expensive) instruments, I
a) am always tethered to an operating (and often moving) piece of hydraulic equipment, and
b) often have to look at several gauges at the same time, but can't physically place them next to each other.
Allow me to illustrate my point with an example of a forest forwarder closed loop transmission test. Why a forest crane? For no particular reason, although I do favor natural environment over industrial. There was a period several years ago when forest exploration was at its highest in Portugal, and I would see lots of these cranes, but I could tell you a similar story involving a fishing winch or an excavator.
If you've never been around forestry equipment before - take my word for it - these field tests are a beautiful exhibition of ingenuity combined with serious circus skills (at least around here - in Portuguese forests).
For starters - these machines don't work on normal roads - they navigate their way about narrow strips of loose soil across the hills that are too steep for a person to walk on, all while hauling a huge load of timber behind the cabin in a manner that seemingly defies physics laws and common sense. Then - when you chance to stand or walk next to one, it's not the "normal" ground underneath your feet - no sir! - it's the same loose soil, covered with bark, twigs, boughs, occasional logs and entire fallen trees, forming an intricate system of efficient leg traps - Saw style!
Naturally, when you want to verify closed loop transmission pressures, you have to put the machine in "combat conditions", which means loading it with timber "to the brim" and making it do several passes up and down the aforementioned "unwalkable" hill, while closely monitoring at least two pressure readings.
Taking into account these conditions, there are three ways of how this operation can be performed with conventional test gear:
Method one - "Walk with me, baby (classical)".
This method is as old as time - you connect a couple of test gauges with relatively long test hoses, and then run next to the machine, while holding the gauges in your hands. This is a very funny thing to look at. A lot of clients appreciate causal entertainment, when they see an adult male, tethered to a piece of heavy equipment, and forced to run up a steep hill in 40C (104F) Portuguese summer, while looking at two round objects that he's holding in his hands, and cursing every other step in his attempts to leap over the obstacles on the floor. It's like the classical movie interrogation technique, when a protagonist jams a suspect's tie in a car window and takes the poor fellow for a "motorized run". The situation becomes even more comical when the running is performed "sideways" - some techs seem to prefer this technique over the "straight running" - true masters of their trade!
Method two - "Walk with me, baby (extended)".
The second method is a natural evolution of the first one, and boils down to the ingenious application of zip-ties to secure pressure gauges in opportunistic places of the machine's frame, and then, basically doing the classical "Walk with me, baby" described above. This does free your hands, but doesn't relieve you of running after the machine uphill or downhill over the treacherous terrain. This is also an entertaining thing to look at - not as funny as a tethered tech hustling his way uphill, but amusing nonetheless, because the fact that you are running after a piece of equipment while gazing at its side with a serious face (presumably because you are performing mental calculations at the same time) - makes you kind of look like a "full moon enthusiast" who desperately needs help. It's also important to mention the fact that reading a gauge under these circumstances is not unlike attempting to read a watch on a hand of a jogging man while jogging next to him.
The extended method should be preferred over the classical, because your hands are free to protect your face when you trip and fall flat on it, in contrast to falling while still holding on to the pressure gauges, in which case you will either be forced to perform the "ditch the gauges" maneuver, or accept the fact that your face's landing will be cushioned by a pair of high precision instruments. Although geometrical shapes (possibly circular) on your forehead will be visible for but a couple of weeks, I would still advise against updating your LinkedIn profile picture during this period.
Method three - "Ride with me, baby".
This technique is state-of-the-art, because it cleverly by-passes the "running" part. In order to apply it you need to take all of your test gear and cram yourself into the tiny single-operator cabin of the tested vehicle (with the operator already inside) and do your best to avoid embarrassing body contact while concentrating on the readings. Since the cabins are expertly designed to leave you with no space to sit and not enough height to stand, being able to balance yourself in a semi-vertical position while the machine is negotiating a steep incline will require a lot of leg and core strength.
Let us not forget about common variations of this technique - such as riding on the outside while hanging on the cabin door (often referred to as "dooring" by experienced technicians), riding the top of the engine compartment, or any other "ride-able" external part of the vehicle in question. The fact that most of the currently existing roller coasters will loose their "wow" factor when you do this exercise on a regular basis is seen as a major turndown by some techs.
Occasionally the method delivers unforgettable memories - like the operator slamming the door over a test hose, or (my personal favorite) a signal wire getting caught by a wheel and the data logger being snatched from your hands and pulled under the 30 ton vehicle. Note that even if you scream to "f@#*ing stop!" the machine will always come to a halt with the logger directly under the wheel. One moment you're looking at a brand new eight channel data logger - and the next one - shh-e-e-ewt!!! - and you're looking at a pair of empty hands. Beat that, David Blane!
Now, all joking aside - I've done it all, and even more!
The two most annoying inconveniences have always been there - being somehow tethered to an installation, and having to look at several readings at the same time, without being able to place the gauges next to each other due to the location of test points. Now when a multi-meter or a tachometer would come into play, this whole "look at them readings" game would become even more awkward than before. And I don't even want to recall big industrial systems, when I simply couldn't be next to a test point because I had to take measurements in an electric board 30 meters away, and had to be able to see the pressure reading in real time... Walkie-talkie, say you? Cellphone? Skype? Video conference? Five guys in "key" places playing broken telephone? Tried it! Didn't work that good. Of course I always found a way, and of course there is always a way! Hell, you could even use a hand gun for data communication, for all I care - one shot - 10 bar, two shots - 20 bar..., 250 bar - call an ambulance!
Naturally I looked for a way to solve this - and I was surprised to find no solution that could satisfy all of my (truth be told - very nitpicky) demands. It turns out that although the market is full of offers of wireless gauges, wireless pressure sensors, and wireless test devices, especially for HVAC systems, these systems aren't suitable for our particular type of diagnostics. For example - the refresh rate of most Bluetooth pressure transducers in not acceptable for testing dynamic hydraulic systems, where a technician needs high refresh rates. HVAC testers don't work with pressures that we do, systems that only connect to a PC can't be used in the field, and also - no matter what system I considered - none were universal - a pressure gauge would only read pressure, and nothing else...
And wanted more - like a lot more, and also as universal as possible.
So I asked myself - what would be an ideal measuring system for what we do in the filed? And then I came up with the following list:
I would like to have a wireless system, that would fit in a palm of my hand, and would show me at least 4 readings on the same screen, maybe more if I need to.
I would like this system to be as universal as possible - meaning - I would like it to be able to display any physical reading that I need - be it pressure, flow, current, voltage, temperature, etc...
I would like this system to display the readings in units that I want, like for example when I measure pressure - I want to see a reading in bar, or psi, or both if I need to.
I would like to have high, preferably adjustable, refresh rate.
I would like to have high speed spike capture (something like 100 Hz sampling).
I would like to be able to perform real time math calculations with the readings, like for example delta P value from two pressure readings, or display power in kW calculated from pressure and flow readings, or maybe display power calculated from a pressure reading and a fixed flow value, or display efficiency in percent, calculated in relation to a given value... Ideally - I would choose a reading - and then apply an arbitrary math formula to be calculated and displayed in real time.
I would like to be able to log all the data, to be able to upload and store it online in a cloud account, and be able to print it out in a nice form for my clients from any computer connected to the internet.
I want this system to be modular and expandable.
Í want this system not to cost an arm and a leg.
So, me and a buddy of mine, who sells and services John Deere equipment, and knows first hand all the "nuances" of field assistance to complex hydraulic machinery, were talking about it the other day, and I was sharing my thoughts about how great it would be to get a system like this one, and he said something that really stuck with me - he said: "You know, they have apps for everything these days, they should have an app for this too, man! What a shame they don't. Hey, you fiddle with them computers and electronics all the time, can't you come up with something?"
And you know what? Seven months later, I can say that I did! Right now I have a working model of a two channel expandable smart industrial monitor (yes, the name is not very original) that can be connected to any industrial sensor with common analogue interface (e.g. 4...20 ma, 0...5V, 0...10V and more) and transmit the reading to an App via a long range Bluetooth module! AK-47 simple!
First - you can get industrial sensors with standard interfaces for almost anything these days! Pressure, flow, temperature, current, strain, weight, torque and what not!
Second - the monitor itself works as a multi-meter, and can measure (and wirelessly transmit) voltage and current, or even both at the same time, which allows it to be used for so much more than just wireless sensor data communication.
Third - since it has a built in DC source (most industrial sensors need to be powered with 10 to 25V), it allows me to use it as voltage source to test low powered stuff like relays and what not (the monitor can supply a regulated 5 to 25 VDC, actively limited to 60 ma).
And finally - the beauty of this system lies in the fact that the App that the transmitter connects to wirelessly delivers you all of the marvels described above. That's right! All of that wonderful stuff like arbitrary unit display, adjustable refresh rate, real time math on a single or multiple channel readings, data logging with online storage - all done in the App! And you know how much Apps cost these days (a hint - the price starts with "fr..." and ends with "...ee"), now do you know how much data loggers cost?
IT WORKS!!! I am only beginning, and a lot of people already expressed their interest in this system!
Right now it's all in super Beta stage, of course, and the next thing on the schedule - lots and lots of documented field tests! I guess I will have to learn how to make YouTube videos again...
Anyhow - this post is already too big as it is, so I will stop here for now. I will "show and tell" the transmitter in my next post, but the most important thing is - IT WORKS!!!
I haven't been this excited since the day my Dad bought me a battery powered helicopter toy when I was 6 years old!