Glencore’s Clermont mine and Custom Fluid Power show the safe testing of pumps through the application of HYDAC’s HMG 4000 handheld measuring unit at Clermont open-pit coal mine in Queensland in a YouTube video.
The HMG 4000 handheld measuring unit is a portable measuring and data logging device whose main applications are servicing, maintenance, or test rigs.
HYDAC mainly developed this tool for all values measured in relation to hydraulic systems such as pressure, temperature, flow rate, and position.
Clermont mine site testing
Clermont Coal Safety Training Manager Jon Noble and Digger and Drills Field Crew member Ben Ellis recount in a HYDAC YouTube video how a maintainer was required to undertake a hydraulic flow test on a Hitachi EX 5600-6’s main pumps.
In order to undertake this task, the machine was under live test, running at a low idle of approximately 980RPM.
In the webinar, Mr Noble and Mr Ellis recount how the maintainer was in the left-hand pump bay adjusting the flow meter load.
The side housing of the flow meter had failed, allowing the fitting and thread for the delivery line to blow out the side of the flow meter.
The consequence of this incident was an injury to an operator’s right leg, near the kneecap.
Images in the webinar reveal the 90 degrees fitting, where the fitting had broken away from the flow meter and the position of the maintainer at the time of the incident.
Old system manual flow test
The manual flow tester is the industry-standard flow tester historically used on-site.
The flow tester comprises a flow meter with an inline restriction valve that is attached to the pump outlet of whatever piece of equipment is being worked on.
Mr Noble and Mr Ellis explain that manual flow testing is not a “nice job” as everyone on-site knows.
Once the pumps are stroked to the highest flow rate it’s necessary for technicians to go down and manually check flows at the minimum pressure, they explain.
“And then to do your testing you would manually rewind this adjustment through the pressure range of the pumps, checking in five different spots.
“You've got your pressure going into the side and coming out the return or the other way in depending on what you’re testing.
“You can check your flows throughout the pressure and flow curve.”
The first check could be at 47 bar, they explain, with checks right up to 294 bar, which is about 4400 PSI.
“So after you've done your initial flow test to see where your pumps are, you come up to your regulators. You've unloaded the pump, you've taken all the pressure off the flow meter, you’ve adjusted your regulator to hopefully where the desired pressure and flow rate should be,” Mr Noble and Mr Ellis explain.
“Then you come back down and load the pump up-cycle through the test again. And you just keep repeating that until you get the desired pressure and flow rates that you need according to the specs.
“Initially, we designed the new proportional control flow unit so that we wouldn't have to use a manual meter. So we came up with a few different ideas on the control system and the relief valve system.”
Data logger capacity
Mr Noble and Mr Ellis highlight that once they discovered the data logger and the amount of information “they could actually record in one go” the proportional control idea “really took off”.
“We designed it so that we could have two remotely controlled flow meters mounted in the machine. We designed it so that we could fit the flow meters on the test day and hook up the hoses and data logging capabilities.
“It really gave us the opening to pick up a lot more information than we were usually getting.”
Images in the webinar show the manual valve to create restriction of flow and the new one controlled by a line relief valve.
“Ours is controlled by this line relief valve that is pre-set at the factory at 315 bar. We can proportionally control it even if anything doesn’t work out or for whatever reason plays up.
“The relief valve is the same style of safety relief valve that you put into a hydraulic system for protection."
On the electronic control, Mr Noble and Mr Ellis show a smooth ramp-up over 15 seconds.
“And just for safety reasons, as you pull that lever down, it ramps pressure off in one second.
“Once it's set up, we don't have to come back in here except to adjust the regulators.”
They point out that the line relief valve section of the flow meter is “basically” redesigned to take the place of the manual flow meter setup.
“So, the main relief valve and the proportional control and transducers check main pressures while you’re doing the testing.”
Images show the flow turbine that’s used to measure the flow rate of oil travelling through the system and the ability to read oil temperature and pressure.
Mr Noble and Mr Ellis explain that the pump control took the place of manual valves or repetitive changing of hoses.
“We can control pilot pressure proportionally to whatever we require, and we can turn on one pump, two or more, and the other valves can control other functions.”
Images show the data logger being used to grade all pressures, temperatures, and engine speed, automatically executing calculations for flow rate versus pump speed.
“This basically makes our life a lot easier than screwing up the manual valve; we just set it infinitely with our joystick. And benefits are that we pick up a lot more information with the new setup,” they say.
“It's all data logged, down to the millisecond. We found a lot of early preventable failures that could quite possibly have contaminated systems and downtime. It’s a lot quicker: we can wind pressure on and off the pump remotely far quicker than you can with a valve. You can zoom in and check different pressure ranges and different flow points on the graph.”
They say that often they can hear when a pump is not working correctly due to “possible internal failure”.
“You can hear it in the pump while you're in the area, but trying to explain that without some sort of logged representation is pretty hard. You can't pull an old pump because it sounded funny whereas with the data logger you can actually see the changes on the data logger on the graph under load the flow pattern changes.
“A good pump is easy to see compared to a pump that has a possible failure.”
They say that more often than not a teardown report corroborates their rejection of a pump, recording that internal failure was imminent.
“We don't have to access the engine bay while the engine’s running because the speed sensors are firmly mounted. And then we're not near the high-pressure hosing that's trying to undo itself off the flow meters and lift off the ground and we're not near any of that working pressure: we're hiding around the corner out of the way,” they conclude.
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