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Sunday, November 2, 2014

Flow and Pressure testing of Hydraulic Circuits

A few years ago we were asked by one of our clients  "Do you do Flow Testing?"
We said "not yet, but we will investigate and get back to you". 
We called our specialist hydraulics suppliers looking for a Hydraulic flow test kit and we were astounded at the prices of flow test kits.
Starting from $4400 and you still needed to supply your own hoses and adaptors to connect to the hydraulic circuit you wanted to test. So flow testing went on the back burner for a while.
Eventually with more and more clients requesting flow testing services we borrowed a flow tester from one of our trusted advisers, Charlie Gray.
Charlie had built his own from bits and pieces laying around his hydraulics workshop and had then mounted it all into an empty Bosch drill case.
The seed was planted and we then took Charlie's Idea a few steps further and designed and assembled our own flow test kit with the following capabilities. 
  • Measure Oil Flows up to 120 litres per minute or (32 gallons/Min).
  • Induce Pressures up to 350 Bar (5150 PSI) 
  • Measure Oil Tempetatures up to 110 Degrees Celsius.
Supplied with two 1.5 meter long  3/4" High Pressure Hoses  and a selection of 28 adaptors allows the user of this kit to virtually connect to any BSP, JIC or SAE Flanged equipment.

We have sold this Flow Test Kit (see picture below) all over Australia. 
Our Price as you see it Under $2000 inclusive of GST.

A flow test is the quickest and least invasive way to quickly check for internal leakage of a suspected component in a hydraulic circuit be it a valve, motor or pump.
A flow test can also be used to ascertain if the engine or motor powering the hydraulic system is in good condition and or even capable of powering the hydraulic system's requirements. 
Hydraulic pumps, directional control valves, relief valves and cylinders in a hydraulic circuit can be individually checked for internal leakage.
Principle of operation,
The flow test kit is added into the hydraulic circuit and is connected as close as possible before or after the suspected component.
Using a relatively easy process of recorded measurements, logic and simple elimination each component can be individually tested and results compared to the performance of the rest of the hydraulic circuit.

The process described below is used for testing a hydraulic pump. 
The flow test kit is installed as close as possible to the pump's pressure port.
The pump is started and allowed to free flow without load. Flow, and temperature are recorded at free flow.
The flow control valve is then slowly closed to induce a resistance to flow and any changes to flow, pressure and temperature are recorded (usually at 20 Bar or 250 PSI intervals) this test is usually carried out up to the pump's maximum manufacturers recommended pressure. 
Results are then compared to manufacturer's data to ascertain any loss in performance. 
As a rule: If a pump at 0 Bar pressure flows 100 Litres Per Min
and flows 75 litres per Minute at 210 bar or 3000 PSI Pressure (75%) it is considered OK.  

Saturday, September 13, 2014

Machines that mimic nature Pulverizer that totally looks like Tyrannosaurus Rex.

Our client calls it the "Pulverizer" and use it to crush, break up and remove the steel bars from large pieces of concrete. They then sell the steel to recyclers and crush the remaining concrete pieces into road base and other usefull building materials.

So what kinds of teeth do you need to chew concrete all day ?
Molybdenum alloy steel.

Interesting facts about the Pulverisers Bite force compared to a few other animals.
Human bite 80 Kg (175 pounds)
Lion 270 Kg (600 Pounds)
Bear 545 Kg (1200 Pounds
Gorilla 590 Kg (1300 Pounds)
Hippopotamus 820 Kg (1800 Pounds)
Salt water Crocodile 1680 Kg (3700 pounds)
Tyrannosaur's Bite force estimated at 2200 Kg (5000 pounds)
Pulverizer's Bite 60,000 Kg (130,000 pounds) 

We are currently rebuilding the big jaw muscle (hydraulic cylinder) that generates this supper bite. 
Next blog on Youtube The Pulverizer in Action.

Saturday, July 26, 2014

Hydraulics Apps that will save you Time, Money and give you more professional image.

Ever blown a hydraulic hose and lost most of the hydraulic oil in the tank and then wondered how much oil you are going to need to re fill it? 

Remember when you were in maths class at school and you learned the fomula for volume ?
No? You were sick that day , or you were busy drawing a caricature of the teacher or it was Friday and you were daydreaming of what you would do on the weekend when you eventually woke up or .... school ...!  Dude ! that was was like .... 25 years ago!
FYI the formula for Volume = Length x Width x Height. All you need is a tape measure and a calculator and then the skills to convert the cubic volume calculated into something usefull like litres or gallons. 

We have had a few training sessions on how to calulate volume of tanks and the more complicated hydraulic cylinders and circular tanks. With some ...... success. We had an incident earlier this month that required multiple trips back to the workshop to get more oil because the volume of the hydraulic tank was estimated rather than calculated.

Now there are apps that you can download for free direct to your smart phone, tablet, iPad or iPhone and all you have to do is enter some dimensions in metric or imperial and all is calculated into usefull and understandable numbers in a matter of seconds. Additionally the entire calculation can then be copied and attached to an email or text message and sent to anyone for their information and further analysis.

Both of the apps shown below are screen shots from free apps by Zanthic Innovations Inc.
First is from Hydraulic Power Unit Calculator this app it also includes a power and torque calculator.

The second screen shot is from Hydraulic Cylinder Calculator this app will also give you the extened and retract speed of a cylinder and the forces generated if you know the pressures and flow rates.

Have fun with these apps and we hope the new financial year is great one for you. 

Screen shot,  Hydraulic Power Unit  Calculator.

Screen Shot, Hydraulic Cylinder Calculator.

Thursday, April 17, 2014

What does a hydraulic cylinder from a 20 ton crane have in common with a hydraulic cylinder from a Mercedes Benz convertible?

They both require a 10 year inspection and rebuild.

With the crane it is mandatory and is required by Australian Law. 
Generally the size and design of these cylinders allow for dismantling cleaning and resealing with the use and application of specialist tools, skills and techniques.

The Mercedes Benz convertible cylinder as with most other makes of convertible car, the internal seals in the clylinder eventually deteriorate and fail causing the roof to malfunction, and worst of all
allowing the synthetic oil to leak out and stain the car's roof trim and leather seats.

Car manufactureres will advise you that the cylinders are not repairable and must be replaced with a new unit this includes their associated high pressure hoses. Generally this is not the case and Mobile HoseFixers & Hydraulics Gold Coast have successfully dismantled and resealed many of these cylinders at a fraction of the new replacement cost. They have also remanufactured many high pressure hoses for Astras, Saabs, VW, Audi and Mercedes Benz. 

Saturday, March 1, 2014

Rebuild Cab Tilt Cylinder Hino Prime Mover.

Most heavy duty Prime Movers utilise a hydraulically operated Cab tilt cylinder to raise and lower the cab for access to the engine for regular inspection and or maintenance. 
These cylinders eventually start to leak and are generally according to the manufacturer a throwaway replacement item ususally costing between $600 and in this case for Hino Prime Mover $3000.

The high cost of the Hino cab tilt cylinder comes from the fact that it is very well designed and built with wonderfull hydraulic and mechanical safety interlocks and electrical limit switches.

Mobile HoseFixers and Hydraulics Gold Coast removed striped cleaned, resealed, reassembled and reinstalled the cab tilt cylinder within 24 hours and they did it all for around 15% of the price of a new cylinder.

Thursday, January 16, 2014

What High Pressure Hydraulic Oil Can Do To Piston Seal

Yesterday we spent the best part of 3 hours trouble shooting the erratic operation of a quick hitch valve on a 30 ton Sumitomo excavator. 
After dismantling the valve and picking pieces of black rubber out of the spool and valve body and wondering where the rubber was comming from, we flushed the lines and let the machine get back to work, after operating for 15 minutes and changing from bucket to ripper and then back to bucket the spool jamed again, During the second clean out cycle we found a small orange piece of plastic and that gave us the strong suspicion that the piston seals in the quick hitch cylinder had failed. 
After we removed the quick hitch and dismantled the cylinder this is what we found.