From the magazine, Microtunnelling, Tunnelling

Versatility of vacuum excavators

As “÷soft’ excavators, a vacuum excavator can dig small precisely-controlled potholes using pressurised water or air without the risk of damaging buried pipe and cable that is inherent with mechanical equipment and tools.

Although most drilling fluid additives are not harmful to the environment, project owners and municipalities began requiring that work areas be kept free of drilling fluids, and compact, maneuverable vacuum excavators could do the job faster and more efficiently than any other equipment available.

While new to many in utility construction, vacuum excavators have been around since the 1950s. The first machines were designed and built by specialty contractors for their own use and were not offered for sale.

“The needs of the directional drilling industry created a demand for vacuum excavators that had not been present in the past, and it wasn’t long before one or more units were found on almost every directional drilling site,” says Richard Levings, Product Manager at The Charles Machine Works, Inc., manufacturer of two vacuum excavator models: the FX30 and FX60. Both models are available as a trailer-mounted package or on skids for mounting on tracks.

While potholing and HDD fluid clean up may have led to the growth in popularity of vacuum excavators, their value extends far beyond supporting HDD activities.

“They can do so many different things, they are becoming known as the most versatile construction package to come along in years,” Levings says.

Vacuum excavators can make small, precisely-controlled excavations for virtually any purpose. Excavations made with vacuum excavation equipment usually cause less disruption to traffic and other surface activities.

Vacuum excavators are effective for digging holes to set utility and light poles and poles to support signs. They can be used to dig short segments of trench in areas where larger equipment can’t be used and in easements crowded with buried pipe and cable. They are used to make small excavations to repair pipe and pipe joints, to cut off service lines, to plug unused pipelines, and to attach anodes for cathodic corrosion protection systems. Small excavations made by the machines are easier and less expensive to fill and repair. Jetting attachments are useful in cleaning out conduit and sanitary and storm sewer lines.

In addition, vacuum excavators are versatile, all-purpose vacuums for cleaning out manholes, catch basins, conduit and pipe, vehicle wash pits, grease traps, and virtually any other clean-up job.

Productiveness of a vacuum excavator is related to a combination of factors, including horsepower and torque curve of the power unit, type of positive displacement pump or blower used to create vacuum, capacity of pump or blower stated in cf/m, speed of air flow through the system, filtering of air flow, pressure and gp/m of water pump in the reduction phase, nozzle configuration of the excavation tool, and amount of water and speed of air at the reduction head.

Other considerations for evaluating equipment include size and weight, capacity of the vacuum holding tank, weight of the unit when holding tank is full, capacity of water supply tank on water models, dust filtering systems on air units, and sound levels during operation.

Levings says the Ditch Witch FX30 and FX60 operate at lower noise levels than other models in their respective classes.

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