ability to maintain velocity and airflow when in operation. A centrifugal blower typically uses rotating impellers or blades to increase the pressure or the air before discharging it. Volume of air: CFM stands for cubic feet per minute and is a measure of the volume of air being moved. For optimal performance, the CFM specification on a vacuum excavator must be in direct correlation to the diameter of the hose on the machine used. Optimal hose size will depend on the type of spoil most commonly being removed. Cobble, for example, will be easier to remove with a 4-inch (10-cm) or larger hose and will require a larger blower. Less challenging ground conditions might only require a 3-inch (7.6-cm) hose and less CFM. The key is having enough velocity so the spoils that enter the hose are suspended until they reach the tank – if the material settles in the hose, it could clog the system. Pressure: Inches of mercury (psi) is a unit of measurement for pressure. It is more or less a function of how much material the vacuum excavator can move, or lift, at a time. For example, 15 inches (38 cm) of mercury is the lift involved to be able to pull a column of water 17 feet (5 m) into the air. The industry standard for trailer-mounted units – and for potholing and most drill fluid cleanup applications – is 15 inches (38 cm) of mercury. More inches of mercury may be beneficial when dealing with heavy fluid or slurry.
Evaluating the dealer and their service and support when shopping for a vacuum excavator is also important. While vacuum excavators are not challenging to operate or much different from other machines to service, having a local dealer that is familiar with them will shorten the amount of time spent learning. Since vacuum excavators usually are not a mainline product for most equipment dealers, finding local support can be a challenge. Buyers should seek out reputable underground construction dealers with multiple locations, so help is never far away.
Vacuum excavators can be equipped with additional options and accessories to increase their versatility. The most popular ones include hydraulic booms to make handling the hose easier, a hot box that warms the water coming out of the high-pressure wand, a core saw for potholing through pavement and concrete, as well as a sewer jester for cleaning pipes. There is also a list of accessories that will increase the number of applications vacuum excavators can be used for including sweepers and cleaners, which can help clean up a jobsite after
an outdoor event, as well as a misting ring to help handle dry dust and debris during microtrenching applications. The use of vacuum excavators is on the rise not only out of necessity, but also viability. The ability to quickly and effectively remove dirt and debris is important to contractors and municipalities. However, before setting out, buyers should compare manufacturers and models to ensure they are getting exactly what they need. Cori Walsh is a marketing specialist for Vermeer MV Solutions.
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Choosing the right unit
There are a lot of different manufacturers and models of vacuum excavators in the market and buyers should weigh their options carefully. It is important to ensure they get the right unit for their needs, as well as the necessary service and support they will require in the future. Many manufacturers, including McLaughlin Underground, offer truck- and trailer-mounted vacuum excavators with a range of tanks sizes starting with 300 gallons (1,135 L). Models also vary in the amount of material they can displace, the volume of air being moved and suction pressure. According to Jeffords, vacuum excavators with a 3-inch (7.6-cm) diameter suction hose is the most popular size for utility potholing work. “Units with this size hose, tend to be on the smaller size of the vacuum excavator models but pack plenty of suction force,” he added. “Of course, one unit isn’t the right choice for everyone, which is why McLaughlin offers several different options in the 3-inch (7.6-cm) hose category. We carry gas and diesel trailer-mounted units, as well as fuel-efficient truck-mounted systems. Users can also choose between spoil tanks ranging from 300 to 3,000 gallons (1,135 to 11,356 L) in size.”
For more information call 800-558-7500 (outside the US call 805-739-0118) or go to melfredborzall.com Borzall, just doing our bit.
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