Suck It Up
Vacuum Systems Are Unsung Multi-Tools
By Bradley Kramer
If you read through past issues of Compact Equipment, you’ll undoubtedly find some reference to the skid steer being the Swiss Army knife of construction tools. It can assist on almost any jobsite. True as that may be, skid steers aren’t the only piece of equipment on the jobsite majoring in multitasking.
Consider vacuum systems. These skid-mounted or trailered tools were originally designed to assist in directional drilling projects to suck up mud slurry, that goo resembling a Wendy’s chocolate Frosty bubbling out of the drill entry and exit holes. Contractors soon discovered that vacuum units could also perform excavation, such as potholing and exposing utilities. And then they realized the tools could help with site cleanup. And landscaping work. And sewer jetting. And watch out for your Frosty.
“People buy a vacuum unit for either exposing a utility or sucking mud,” says Dave Gasmovic, president of McLaughlin in Greenville, S.C. “Those are the two primary roles. Once they have a vacuum, they start finding a lot of other applications where it’s easier to use the vacuum than labor.”
If skid steers are a Swiss Army knife, vacuum systems are a trusty lock-back pocket blade, which may have been designed to cut, but you can use it like a screwdriver, a shovel, a bookmark, a pry bar and so on. Skid-mounted and trailered vacuum systems combined with a pickup truck add a versatile tool to any jobsite that requires moving material like dirt, dust and debris, whether for digging or disposal.
Vacuum systems may have been designed for the specific use of sucking mud, but manufacturers like Ditch Witch, McLaughlin, Vacmasters, VacStar and Vac-Tron Equipment have seen their customers diversify vacuum applications. Mirroring that trend, the customer base has also grown from primarily construction contractors to utility owners, municipalities and landscapers.
Construction contractors still use vacuum systems for directional drilling projects, potholing and exposing utilities, but also for general cleanup of excess material. Municipalities have added vacs to city fleets for water and sewer work like cleaning valve boxes and sewer jetting, but also for sweeping parking decks. Landscapers have found vacuums useful for transporting material and installing underground sprinkler systems, which lie at similar depths as fiber-optic and copper wire lines.
Vacuum systems are well suited for individual construction or landscape crews because they can often be purchased so that the total weight of the unit, skid or trailer and truck all weigh less than 10,000 lbs GVWR, avoiding the necessity — and expense — of a commercial drivers license (CDL) to haul it from the storage garage to the jobsite.
Vacuum systems range in price from about $14,000 to $80,000, depending on size, options and any additional accessories. Units are typically sized by the capacity of the spoils tank and blower power, which creates the airflow needed for suction. Vacuum systems employ either high-pressure air or water to break up material before the vacuum sucks it into the spoils tank. However, McLaughlin recently released its first combined air and water vacuum system at ICUEE in October (See page 53).
In recent years, vacuum systems have become more popular rental items. Rental yards were a little slow on the uptake because the companies may not have seen the broad applications that vac units can perform, says Ditch Witch senior product manager Brent Bolay. Typical rental rates vary from $300 to $420 per day or $2,700 to $4,800 monthly, Bolay says. Rates will depend on the size and capabilities of the vacuum.
Selecting Your Suction
Purchasing or renting a vacuum system requires the operator to know what the project is. Choosing the right system depends on the type of material being vacuumed. Soils, for instance, can vary from dry and sandy to hard clay. Just knowing the material goes a long way in determining what size vacuum is needed.
The two biggest concerns when picking the right size vacuum unit are spoils tank size and blower power, followed by filtration, Gasmovic says. Standard spoils tank sizes are 100 gal, 250 gal, 800 gal and 1,200 gal. The 100-gal tank is small enough that it can fit in the bed of a pickup truck.
Jobs that require a tank larger than 1,200 gal usually require the large scale truck-mounted systems built by Vac-Con Inc., Vacutrux, Vacmasters and Vactor Mfg. Those vacuum systems cost as much as $400,000 and are almost exclusively used in sewer projects.
Blowers, which create the airflow necessary for vacuum, are the heart of the vacuum system. Blowers are measured by either horsepower or cubic feet per minute (cfm). McLaughlin offers two blowers: a 575-cfm unit and 1,025-cfm unit, both providing vacuum pressure rated at 15 in. of mercury, which is about 7.35 psi. However, the blowers push air at 130 mph through the vacuum hose, which Gasmovic says is the most important spec.
“People get confused with vacuums,” he says. “Because when you say the word vacuum, all the sudden you’re thinking, ‘How much suck pressure does it have?’ But for vacuuming solids, drilling mud or potholing utilities, anything with any bulk to it, you need airflow, not vacuum. [130 mph is] what the engineers have determined to be the proper volume to keep the spoil material in suspension through the hose, so it doesn’t lay down and plug the hose.”
Ditch Witch offers two models, the FX30 and FX60, which can be fitted to any of the company’s 500- and 800-gal tanks, Bolay says. The FX60 is also available with a 1,200-gal tank. The FX30 provides a 30-hp power pack (engine), whereas the FX60 provides 60 hp.
“You would choose more horsepower if you knew a job had longer suction [distance] or you had larger, tougher material,” Bolay says, “or if you’re going to be running [the system] all day, not intermittently.”
The hoses that stem from the blowers are usually 3 to 4 in. Basically, the difference between the 3- and 4-in. diameter hose with the different size blowers is that you’ll move about 70 percent more material with the 4-in. hose. After choosing the proper tank size and blower, filtration is the next biggest concern when considering a vac unit, Gasmovic says. Filters protect mechanical parts and influence the efficiency of the vacuum.
“If you think about your vacuum cleaner at home, it has a bag in it. When the bag gets full of lint or debris, the vacuum quits working properly,” Gasmovic says. “The more you get in the bag, the less efficient the vacuum becomes.”
And just like those domestic vacuums, skid-mounted and trailered vacuum systems come with a variety of filtration systems. Filters range from manufacturer to manufacturer. There are bag house filters, single element cloth or paper filters and cyclone filtration systems. Single element filters and filter bags can clog and require routine maintenance.
McLaughlin offers a three-stage, cyclone filtration system, which spins the dirt and debris out of the incoming airflow into a collection tank. The air then passes through a final, two-micron poly washable filter that cleans any other fine particles out of the air, which protects the blower from anything big getting into it. Ditch Witch uses the single element filter, which Bolay says is basically a large surface area polyester filter that can be removed to be cleaned, using low pressure air or washed with water and then dried.
“A real key to operation is to have a good filtration system,” Bolay says. “Because of the blower operations, it’s trying to pull fines and dust up into the blower, which over time will degrade the fans and bearings. It becomes a wear and tear issue.”
Knowing what kind of material the vacuum will be primarily used for will help determine one other main factor: whether to go with air or water. Vacuum systems employ high-pressure air or water to reduce or break up soil or other material so that the vacuum can suck it into the tank.
“You can’t just set the vacuum on the ground. You’re not going to move much material that way,” Gasmovic says. “The biggest advantage of air is that you have dry material when you’re exposing a utility so that you have dry material that you can put back in the hole. The biggest disadvantage to air is it doesn’t work with all soil.”
Air is not as effective at breaking up hard soil or clay, Gasmovic says. Water is more effective with denser materials.
“The advantage of water is that it will break up more soils,” he says. “It also will dig faster than air. The biggest disadvantage is that you have mud in the tank you have to dispose of.”
Haul that Sucker
The majority of vacuum systems sold in the United States are sold on trailers, Gasmovic says. However, skid-mounted units are available that can be moved from a flatbed truck to the ground or elsewhere if need be. Smaller units, such as a 100-gal unit can be fitted into the bed of 3/4-ton pickup.
Trailered vacuum systems can be purchased to weigh less than the 10,000-lb GVWR (with truck) CDL limit, but range up to 264,000 lbs of GVWR. The operator will need to size the trailer to the type of truck used. A unique aspect to towing a vacuum system is the tongue weight, Gasmovic says.
“One of the comments you hear out in the field is that it’s a little heavy tongue weight-wise,” he says. That’s because vacuums tend to be heavier at the trailer’s tongue when the system is empty. But you don’t want negative tongue weight. Once the vacuum starts to fill, the weight of the trailer evens out as the spoil deposits into the tank, which is usually at the rear of the trailer.
When operating a vacuum at a jobsite, Gasmovic suggests having a ready dump site for material like mud or drill slurry.
“It’s usually a good idea if you have a place on your yard where you can dump the material, let it dry out for a day or two and then be able to reuse it,” Gasmovic says. “You can get a cycle going where you dump the wet mud, take dry material to the site to backfill and then the wet mud dries and you’re able to use that another day. If you have that kind of cycle, it’s more cost-effective than trying to find a landfill to dispose of the material.”
More Ways to Play
Vacuum units typically come standard with a suction tool and spray wand. But if you really want to trick out your vacuum system, there are a number of accessories and features that can be fitted to the unit to boost its efficiency and versatility.
A reduction system lowers the psi of the water or air stream so that the vacuum breaks up soil more gently. Vacuum systems were originally devised as damage prevention tools, Gasmovic says. Most water systems run at about 3,000 psi, but you don’t want to go over about 1,500 psi or you risk damaging underground utilities in the area. A vacuum boom can help operators manage the suction tool more freely, Bolay says. An extension arm rises from the top of the unit and uses hydraulics to raise, lower, extend and retract, as well as allowing rotation around the vacuum.
A sewer jetter is a tool that hooks to the vacuum’s water hose and sprays water in multiple directions to break up a clog in a sewer pipe. A pavement sweeper attaches a squeegee-like tool to the system to help vacuum mud and other debris from streets, sidewalks and parking decks. A “two-in-one” tool is used for potholing work, Bolay says. The tool hooks the water stream and vacuum together, so that the operator can spray water and vacuum at the same time.
Suction Safety
Operating a vacuum unit is fairly straightforward and is spelled out in the accompanying owner’s manual. However, Bolay and Gasmovic emphasize that the key to proper use revolves around safety — safety for both the operator and the surrounding and subterranean environment.
“With more and more utilities in the ground, to work around them, even with landscaping, is becoming more of a challenge,” Gasmovic says. “These are damage prevention tools. You don’t want to make them the instrument that causes damage.”
Knowing what utilities are in the ground at a particular jobsite is critical, Bolay says. Both air and water have the potential to cause damage and special care should be taken when working around service lines. When reducing the soil for vacuuming, Gasmovic suggests reducing the water pressure to avoid damages. If the vacuum system uses air, he says, “Let the air do the work. Don’t use the air knife [a type of nozzle tool] as a pick by digging with it.”
Vacuum Upkeep
Like any piece of fleet equipment, vacuum units require some routine maintenance. Vacuums don’t have as many mechanical parts that require greasing because air is the primary force moving through the system. However, there are some parts in the blower that require a soothing oil bath and grease. Fuel — the majority of vacuum systems use diesel — and other engine fluids should be checked daily.
The primary maintenance point is the filtration system, Bolay says, particularly if the vacuum uses a single element or bag house filter. The filter should be checked daily at least and more often depending on the material being vacuumed.
Bradley Kramer is a contributing editor of Compact Equipment.
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