For municipalities and contractors who clean endless miles of sewer lines, the goal is always to clean more with less effort and fewer resources.

Making that goal attainable is innovation in lightweight skid nozzle stabilizing attachments, enabling cleaning crews to move through lines more easily than ever without getting caught on obstructions such as protruding taps, offsets and deflections.

Today’s advancements in skid design can substantially improve the balance and maneuverability of nozzles and hoses to speed up sewer cleaning. When used in conjunction with high-performance nozzles, the combination provides faster cleaning that uses less power, pressure and water. The approach not only eases operator workloads but also reduces the cost of vacuum truck fuel, water use and mechanical wear and tear.

Less flow, same power

To maintain stability with high-volume jetting, operators typically use nozzle skid attachments to keep the nozzle and hose centered within the sewer pipe. Today, some designs go far beyond this basic function and can significantly improve safety and performance.

“More advanced skids with holes are designed to balance the nozzle inside the pipe and prevent the nozzle from becoming airborne and coming out of the manhole,” says Dan Story, operations manager at KEG Technologies, a manufacturer of sewer products including Tier 1 to Tier 3 nozzles, chain cutters, floor cleaners and camera nozzle systems. “Providing additional holes allows the user to secure the nozzle on the skid while inside the pipe.”

The challenge is that traditional skids are often constructed of steel, which adds weight and reduces maneuverability within the sewer line.

In response to these challenges, Story says he sought to ease cleaning sewer lines. Through testing and experimentation, he discovered a specific technology that could have major implications for municipalities and contractors tasked with cleaning more lines with fewer resources.

“I discovered that if I used a high-performance aluminum nozzle with an aluminum skid, I could gain approximately 30% more power than typically available through conventional options,” he says. “That meant I could lower the nozzle flow and pressure and still have all the cleaning power I had before.”

Additional design tweaks

Story has further refined the skid design after doing additional research, development and testing. The new skid design uses a lightweight aluminum pipe core with protruding plastic fins to provide nozzle stability without the weight of heavier steel skids. The skid design resembles the shape of a football to reduce the risk of snagging on sewer pipe obstructions.

“The design lowers the weight and drag of the skid and nozzle in the pipe. The lighter the weight, the easier it is to propel up the line,” Story says. “The football shape and the slick plastic fins also reduce friction, allowing the skid to pass over common sewer pipe obstructions, such as protruding taps, offsets and deflections. If it hits a deflection in a pipe, for instance, it will climb on top of the next step and keep on going.”

The approach enables superior sewer line cleaning with significantly less power, psi and water, which translates into important advantages in the field.

Staying centered

Cleaning sewer lines at lower pressure reduces the load on vacuum trucks. Toward this end, using a lightweight aluminum skid improves nozzle maneuverability to keep the jetted water stream centered within the pipe and focused where it needs to clean.

When used with a high-performance aluminum nozzle, the combination can produce at least 30% more cleaning power than traditional options because it keeps the jetted water stream centered within the pipe and focused where it needs to clean. This reduces pressure and water use while still achieving efficient cleaning. Just as important, it allows the operator to lower the vacuum truck’s rpm, allowing for better conservation of the vehicle’s fuel use as well as decreased mechanical wear and tear. 

“Operators can essentially run the vacuum truck at idle if they are using an aluminum skid and nozzle. They do not have to crank up the truck’s rpm,” Story says. “Instead, they can effectively clean sewers with as little as 1,000 psi at 35 gallons a minute. It’s a game-changer for cities.”

Another benefit of sewer cleaning at lower psi is reducing the risk of blown toilets, which can leave sewer material on the floor and toilet seat, upsetting homeowners. A blown toilet typically occurs when an operator rushes up the sewer line with minimal cleaning on the first pass. This results in excessive debris on the return trip through the same stretch of sewer line. Airflow from the nozzle then compresses between the nozzle and the debris, creating significant positive pressure. When the debris passes by a home’s service line, the pressurized air blasts up and out of the service line, causing a blown toilet. 

“When sewer cleaning, lowering the pressure involved reduces the risk of a blown toilet, and can be particularly effective when cleaning shallow manholes, which are more prone to the issue,” Story says.

According to Story, he was able to demonstrate the effectiveness of this technique when a West Coast city invited him to do a demonstration for them. 

“Previously, the city was challenged with a blown toilet problem at a home that occurred virtually every time they cleaned a certain line,” Story says. “They asked, ‘How can we fix this?’ We went in at 1,000 psi with an aluminum nozzle and skid and cleaned the entire sewer line without blowing the person’s toilet.”

Alternatively, the approach can provide more cleaning power on tough jobs such as accumulated grease at restaurants.

“The sewer line on a street with a fast food restaurant was full of grease,” Story recalls. “A municipal supervisor doubted the cleaning effectiveness of using an aluminum skid and nozzle. He couldn’t believe his eyes when the technique quickly liquified the grease.”

A range of options

To accommodate the range of sewer pipes in the field, KEG Technologies offers aluminum skids in 6-, 8-, 10- and 12-inch sizes for use with aluminum Tier 3 nozzles. There are several tiers of nozzles, rated for water efficiency — Tier 1 (about 30% efficient), Tier 2 (50-60% efficient) and Tier 3 (75-98% efficient). 

What sets the most efficient Tier 3 nozzles apart from others in the category is fluid mechanics engineering on a par with the aerodynamics of race cars or fighter jets. In the case of KEG’s aluminum Tier 3 nozzles, such as the Royal, Cleaning Torpedo and Aluminum Traction, the high-performance fluid mechanics design leaves little room for power losses and excessive turbulence, says Story.

“By more effectively containing, controlling and directing high-pressure water with less turbulence, an aluminum Tier 3 nozzle can deliver more cleaning power at lower psi,” Story says. “This eliminates the need for operators to compensate for the lack of power from Tier 1 or 2 nozzles by increasing the pressure to higher psi on the way back through the line. Ultimately, less psi — with a better, faster result — facilitates safer, more efficient sewer cleaning that complements the use of an aluminum skid.”