Hydraulic drive pumps for insitu line boring and surface facing have historically been heavy for operators to handle and lacked control and power at low cutting speeds. AVS Engineering, in Bellevue WA, has recently released a brand new innovation in this area – a DC servo controlled hydraulic pump.
The new pump is the result of extensive design, development and testing in WA and is based on AVS’s need for more consistency and control in their own jobs on mine sites across the state. The product they have developed is now available for sale to other onsite machining companies.
Conventional hydraulic pump controllers for these applications regulate cutting speed by restricting the flow of fluid to the pump. This creates two problems, the first is that heat is generated and that requires a large reservoir of fluid to be taken to site in order to have enough volume and tank surface area to cool that fluid during the machining process. The second problem is that reducing the flow of fluid to the pump significantly reduces the amount of power it can produce at lower rotating speeds. This is not ideal if more power is needed to cut through harder material.
Faced with the ‘that’s how it’s always been done’ mentality, AVS decided to come up with a better option on their own. They enlisted the help of electronics experts and applied their own knowledge from decades in the field carrying out onsite machining on every possible piece of equipment. The end result is a revolutionary, DC servo controlled hydraulic pump that can electronically manage any hydraulic cutter or mill.
Three-phase AC power is supplied to the control box, which is converted to DC, which supplies the DC servo motor that drives the hydraulic pump. The fully intelligent control system is making hundreds of calculations a second and measures load on the pump, inertia and also calculates and compensates for the length of hose connecting the pump to the borer and allows for the internal losses from that hose.
Because the speed of the pump is being controlled by a DC electric servo, full flow, and therefore power, is still available to the cutter even at low speeds. Thus, the cutter will not bog or stall at the slow speeds required to cut harder materials, resulting in a perfect finish and much less operator stress. An added bonus is the reduction of heat imparted into the hydraulic fluid during operation. This reduces the volume of fluid required, which makes the entire unit even more mobile. Note that the fluid reservoir sits neatly under the DC motor and pump – only 20l are required.
What’s more, the intelligent control box can instantly compensate for variances in the hardness of the material being machined. If the cutting tip suddenly encounters a harder material, the controller instantly responds by applying more load to give an even cut. Conversely, if the material is soft and consistent, the controller with reduce the load to provide consistent machining.
The photos show the controller, pump, hoses and all necessary equipment housed in a purpose-built trailer. It is possible, if required, to remove the DC motor and pump and move it closer to the job if required. It is light enough to be easily handled and can be taken up scaffolds or in a lift on site.
The remote controller for the unit is housed in an aluminium case, not a plastic one. AVS know how hard some of this equipment works on site, so they have made their controller tough enough to take the knocks but still light enough to use all day without undue operator fatigue. The controller is also fully earthed and the system continuously checks the status of that earth for complete operator safety.
In-house and Onsite Machining
Apart from designing, building and now selling revolutionary electronically controlled hydraulic pumps, AVS Engineering has full in-house and onsite machining capabilities with all the equipment needed for minesite maintenance, refurbishment and repairs.
Line boring has been their mainstay for many years and their capabilities in this area are second to none. AVS can deliver accuracy within 0.002-inch over a span of 12m to ensure even the widest spaced pin bores run perfectly true, centre to centre. Their equipment allows them to handle bores from a tiny 35mm to a massive 1200mm in diameter, which caters for everything from the smallest PTO link to the largest excavator arm.
They regularly take on the large jobs or the tricky jobs that require out of the box thinking and the fabrication of custom tools. One recent example was the repair of the rails on a 50t crane fork. Bearing failure had caused significant damage to the inner and outer runners on the lift, so AVS built an automated surface grinding rig to run up and down the inside of the rails to machine them back to a flat surface after reclamation welding had been completed.
AVS’s founders, father and son team Vaughan and Adrian South, have decades of experience working on mine sites across the country and all that expertise is passed on to each and every client. This is what enables them to solve difficult engineering problems and come up with innovative solutions.
A major part of their business is in line boring and surface machining and that has led them to design and build the new DC controlled pump, which is now available for other machinists to purchase. Australian know-how and expertise applied to Australian industry – a cutting edge success story.