A Fair Shake

Engineered vibration technology makes its way into the sewer cleaning market
A Fair Shake
The Cougar vibrators reduce offloading and cleanup time, and also help workers avoid the temptation to intervene in an effort to extract the hopper’s entire contents. (Photo courtesy of Vactor Manufacturing)

Vibration technology, which is designed to loosen stubborn loads in the industrial loader market, is now being promoted as an effective tool for sewer trucks and catch basin cleaners. In the wake of re-engineered vibration modules offered specifically to the Vactor Manufacturing truck line-up, the company is actively promoting their use outside of the industrial-only market.

The technology is particularly effective at helping to dump dry loads, thick sludges, catch basin debris and hydroexcavated material from vehicle tanks without operator assistance. The vibration units are being built by Cougar Vibration, a Division of Martin Engineering, a long-time Vactor supplier.

“We’ve offered engineered vibration technology as an option for several years, but on an order-only basis for sewer cleaners — we weren’t heavily promoting it,” says Ben Schmitt, sales application engineer with Vactor.

“We’ve had perhaps a dozen orders over the past five or six years in that sector. Vibration technology has no affect on pure liquid loads. However, with the economic challenges faced by a lot of operators, they’re trying to get the most out of their equipment investment by expanding the range they’re expecting from their machines. We’re seeing a lot of operators multitasking by going into the hydroexcavation market, which has them dealing with large numbers of dry loads that they may not be accustomed to dealing with. They’re also venturing into new territory that may see operators willing to take on contracts involving drier loads that simply are not as easy to offload as what they’re used to.”

 

Vibration aids flow

A small but powerful vibrator motor mounted underneath the debris hopper or tank provides the vibration, which aids the flow of semi-solid and solid materials. The units are rigidly mounted on steel channels underneath the tanks and hoppers, so the vibration is carried throughout the load and can be distributed over the entire unit.

“Cougar patented the first truck vibrators in the 1960s, and vibration technology and material flow have been the sole focus of our company since then,” says David Ruggio, technical support manager with Cougar Vibration. “Whether it’s a vacuum tank, dump body, chute or a stationary hopper, the principles and application of vibration to induce material flow are the same. All rotary-type vibrators operate on the same principle of an off-center rotating mass — or simply, a wheel out of balance. It might be easier to think of the vibrator as mechanically reducing the coefficient of friction between the material and the tank wall.”

The small size of the units, however, is no indicator of potential output. A vibrator generating 1,000 pounds of force could be engineered to the same physical size as a unit generating 3,200 pounds of force — it’s the mass of the rotating wheel inside the vibrator that determines the vibration force output available. The output of the vibrator is selected according to the cubic yard capacity of the tank or dump body and the weight, consistency and moisture content of the material it may be carrying, whether it’s catch basin debris, sludge, sand, mud, rock or industrial products.

 

Vibration targets solids and sludge

“Vibration units are used less frequently in sewer-only applications,” says Brett Hart, product manager with Vactor. “When sewers are cleaned, the water in the load is often returned to the sewer by decanting, but the solids and sludge remain. Dewatered sewage or sludge can have a tendency to compact in truck tanks, making it difficult to dump. If pressurized body washout-jets are not utilized due to the nature of the dumping location or environment, vibration can assist the offloading of material by disturbing the surface to which the sludge is sticking. The vibrator will break the surface tension between the material and the hopper wall, breaking up that packed material and allowing gravity to take over and slide the material out.”

But operators with an eye for cost-efficiency are finding that they may opt to select vibration-only technology for specific applications, depending on their range of requirements.

“Typically, sewer cleaners are equipped with a high-pressure water capability that usually flushes away a slurry material that may not break free on its own,” notes Schmitt. “But operators are now being given the option of deciding between equipping their units with a debris body flushout or a vibrator unit, which could be better suited to their needs if they were typically offloading drier material.”

The vibration units may also prove effective for contractors operating the Vactor combination cleaner line, particularly if they’ve ordered a hydroexcavation kit to augment their equipment. Operators opting for vacuum-only units used as catch basin cleaners may also benefit from the vibration units, because of the relative dryness of these loads, which tend to compact significantly under vacuum pressure.

“The vacuum-only catch basin machines offer a small jet gun to wet things down and help with offloading, but a vibrator may actually do a better job of assisting operators in loosening those compacted materials,” says Schmitt.

 

Eliminating operator assistance

Hart notes that the vibrator can add another measure of operator safety to the Vactor units, since any temptation to provide human assistance in emptying loads, a dangerous temptation for operators on a tight schedule, is eliminated.

“All vacuum loaders must be enclosed to work … they can’t be open-top dump trucks,” he says. “The debris hoppers on Vactor hydroexcavators and vacuum loaders are activated by a dump mechanism that rises to a 50-degree angle for offloading, but often some of the contents stubbornly resist emptying. Without the vibrator, a worker may be tempted to climb into the unit or under the raised load to use hand tools to finish the job. This places the worker in an unsafe condition, which should always be avoided. The vibrator option allows the operator to flip a switch when the tank is raised and break the surface tension, quickly evacuating the material.”

A Vactor partner for two decades, Cougar is the exclusive supplier of the vibrator units for all Vactor models. Hart says the quality of the product and vendor support were the key factors in the decision.

“Vactor demands quality components and values good working relationships with vendors,” he says.

Ruggio says that open lines of communication are critical to developing such products for niche markets.

“The excellent communication between the two companies has been key to our mutual success,” he says. “It helps us better understand the specific applications and match the vibrator to the job, including the sewer and catch basin market.”

 

Engineering out redundant components

That relationship was critical to Vactor’s request to re-engineer the vibration units to eliminate any parts not critical to their operation on the Vactor line.

“We eliminated a mounting plate and some wiring that is normally already supplied with the Vactor units,” says Ruggio. “Because Vactor does its own mounting and wiring, we eliminated those parts and brought the cost per unit down.”

Vactor estimates the cost per unit savings realized by the re-engineering at about $40 per truck, one of the key factors in promoting the technology in the company’s current sewer truck line-up.

“Over time, that savings across the product line will be significant,” Hart says.

Each of Vactor’s industrial trucks are being fitted with a vibrator mounting plate, whether ordered with a vibrator or not, so a retrofit is reduced to an easy bolt-on installation. Sewer trucks require the mounting plate to be added, also a simple operation. The 12V electrical vibrator units have become standard equipment on all Vactor industrial vacuum loaders.

Vactor has specified four different Cougar Vibration vibrator models for various applications across its product line. The vibrators are available in electric models, or a hydraulic model specifically designed for intensive industrial applications.

The heavy-duty electric-powered units include the DC-3200. Suited for large spreaders and vacuum trucks, it delivers 4,000 vibration cycles per minute (vpm) with 3,200 pounds of force, while drawing 85 amps using the 12V model and 62 amps using the 24V model.

 

Hydraulics for continuous operation

The Cougar HA4-3300, a variable-speed hydraulic vibrator with adjustable eccentrics to control vibration, is designed for heavy industrial users. The motor is capable of a maximum output of 4,500 vpm with 3,278 pounds of force, and is designed for minimal power consumption and low maintenance.

“The hydraulic vibrator offers a longer duty cycle which is critical if it’s used heavily,” notes Hart. “That’s not usually the case for sewer and catch basin cleaners. The electric models will burn up if used for long periods of continuous duty, due to the amperage draw, while hydraulic units won’t. But electric vibration models are probably going to be sufficient for most sewer, catch basin and hydroexcavation applications.”

Hart says the company expects that the vibration units will likely increase both operator productivity and safety.

“Promoting an increase in the efficiency of material flow while eliminating operator intervention is a win-win,” he says.



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