Seeing hydraulic equipment on job sites is commonplace so it’s easy to overlook some accessories that may be needed. When looking to raise a heavy load while maintaining level and control, rams are an easy option. Knowing what else to include in your bid not only helps you stay on budget, but also ensures the project runs smoothly.
The first step in determining what to include on a hydraulic bid is to analyze how tight the tolerances are. Do you need the load to lift completely even with minimal variance between the leading and lagging cylinders? If so, you may need to consider synchronous options. If tolerances allow for minor variation, the available pumps expand considerably, as do the methods of controlling the lifting speed. Let’s break this down briefly:
- Structures requiring near-perfect synchronization from leading to lagging – frequently across several lift points – are best suited for a synchronous pump. For example, Enerpac’s EVO-series computer moderated lift system achieves accuracy down to 0.040” between the leading and lagging cylinders. One typical application for this type of unit would be bridge maintenance.
- For less stringent applications, a split-flow pump allows for a high-degree of accuracy without the computer aid. A 40-gallon split-flow pump would be suitable for applications where synchronization of up to 4% is acceptable. Typical applications for this include some bridge bearing maintenance, stage lifting in shipbuilding, skidding, or leveling large structures like wind turbines.
- On non-critical lifts where relative accuracy will suffice, there’s always the manual option, incorporating a pump(s), manifolds and pressure gauges. This setup allows the user – or users on dual pump lifts – to manually adjust flow rate based on the pressures measured at each ram.
Once you have determined which pump works best for your lift, the rest of the components fall in place rather quickly. This includes everything from adding needle or check valves to the selection of the most suitable style of ram.
Let’s say, for example, you will need to have long periods of prolonged suspension. In that case, a locknut ram is the best option with its locking collar that operates independent of hydraulic fluid once extended. In theory, check valves prevent the reverse flow of fluid after removing the hose, but this isn’t the safest option.
If your main concern is controlling the flow of fluid while extending and retracting, a needle valve can help moderate. Modern gas and electric pumps frequently come equipped with vacu-valves that actively pull fluid back into the pump. While immensely beneficial in the right application, paired with a flat jack or pancake ram, this can cause the plunger to rapidly slam back down, potentially damaging both the ram and the load you are lifting.
Manifolds and pressure gauges, referenced above, also play pivotal roles in safe and efficient jacking. Manifolds can be used independently or joined together to form a complex system, depending on your specific application. Having individual ports with shut-off valves allows for manual control over where the flow of oil runs. Pressure gauges would pair up with the manifold to measure actual pressure to each ram and ensure that no cylinder sees a disproportionate load share.
Other pieces of equipment to consider, when applicable, would include spreader jacks or hydraulic or rachet jacks. Depending on the space available, you may need additional height below the load to set the ram in place. While not needed on every project, it’s important to consider whether adding some of these on your project is necessary. As always, proper preparation before beginning any lift is the most important factor in avoiding unnecessary downtime.
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