Synchronous jacking is a relatively simple concept in nature – raising an object or structure at the same time to avoid causing damage or failure. There are several methods to achieve varying levels of synchronization, the key is determining the degree of precision necessitated by the project.
Many projects where synchronous lifting is requested can be completed with a setup as simple as utilizing a large enough hydraulic pump, pressure gauges and manifolds assembled to accommodate the appropriate number of rams. In that setup, one person stands back at the pump and manually adjusts the flow to each ram based on the readings taken from the pressure gauges. While this method will keep the load relatively level, the margin of error is considerably higher than other methods.
For projects requiring greater precision, Enerpac has created a split-flow pump that provides lifting accuracy of 4% as stated in their product release. Split-flow pumps provide a better alternative for projects such as bridge lifting for bearing replacement, wherein the accuracy of the lift is paramount to maintaining the integrity of the bridge. The electric pump can be used to advance, hold or retract (for double acting cylinders) the load using either a joystick or pendant and can even operate the rams individually when needed. Split-flow pumps act as an intermediary between manually operated manifolds and the next option, the synchronous lifting system, also referred to as an EVO system.
The EVO system is a computer controlled system that gives the user the most precise lifting option, with tolerances as tight as 0.04” between the leading and lagging cylinders. While the tolerances make the EVO synchronous lifting system the best option for projects where precision is key, the software system is fairly complex and would generally require a representative from Enerpac to be brought out to the site.