Innovative Roll Handling Equipment Can Boost Safety and Save Energy

Safety and energy savings are both critical topics when it comes to paper mill operations. First and most important is operator safety, as working with moving products and machinery can lead to potentially hazardous situations. Second, the product uptime in conjunction with machinery safety is very important to daily operations. Damaged equipment can cause production stops that lead to high costs. Moreover, damage to paper rolls can result in poor product performance and monetary losses. Energy savings have also become increasingly important to profitability, especially in the current global energy crisis.

moverolls horizontal conveyors are flat and modular
MoveRoll’s horizontal conveyors are flat and modular.

One company developing innovative roll handling solutions is Finnish company MoveRoll Oy. MoveRoll’s unique roll handling equipment offers several benefits for system integrators and paper mills.

Easily integrated into roll handling systems, MoveRoll’s products gently convey, kick, receive and slow down paper rolls to boost safety and save energy. Easy installation and maintenance result in savings for both system integrators and paper mills.

HOW DO THESE CONVEYORS INCREASE MILL SAFETY?

MoveRoll Conveyors are flat (40 mm) and have a modular build. It is easy to install them on a level factory floor. The conveyors use standard pressure elements to transport rolls using a rolling motion. Traditionally, ramps or sloped floors in the finishing area are a risk to operator safety when rolling paper or cardboard rolls move freely on them. The rolls can gain speed, move in an uncontrolled fashion, and bounce heavily when they hit the steel stops. Consequently, paper mill staff working on or near these ramps are at risk of being hit by paper rolls or crushed between them.

A MoveRoll conveyor does not require sloping ramps for moving rolls from point A to point B. Instead, compressed air in the pressure elements actuates the rolling motion and the pressure elements transport the rolls safely—and always at controlled speed. This method also avoids changes in rolling direction. MoveRoll horizontal conveyors use only 2.5 Bar compressed air to move rolls up to 10,000 kg. With low air consumption and no mechanical components, paper mills can significantly reduce energy costs in the roll handling section.

compressed air in the pressure elements actuates
Compressed air in the pressure elements actuates the rolling motion and rolls are transported at a controlled speed.

Plus, MoveRoll engineers its conveyors against power failure. If the compressed air supply should fail and the MoveRoll conveyor is mounted on level ground, the rolls stay where they are. In case they are rolling, rolls lose power and usually stop within less than half a meter.

EPIQ-AD, a MoveRoll premier roll handling technology partner based in Montreal, Quebec, has installed dozens of MoveRoll systems. “The MoveRoll technology is a game changer for roll handling safety,” comments EPIQ’s General Sales Manager Peter Hanna. “The most surprising thing for mill operations is that the horizontal pressure elements have ‘zero-energy safety’ built in. If you lose the air or the power, the roll stays stationary. When power and air return, it restarts without any headaches. Traditional roll handling machinery would need to include mechanical devices such as safety pins and toggles. Mechanical devices wear out; the MoveRoll conveyor has no mechanical devices.”

BRAKING PADS ADD SAFETY

More than 150 paper mills worldwide use MoveRoll Braking Pads in different applications to reduce roll speeds in the finishing line while maintaining maximum production rates. The braking pad is a simple, innovative solution based on the principle of reducing the kinetic energy of the incoming roll. The combination of soft material, air exhaustion, and absorption of kinetic energy can reduce roll speed up to 0.5 m/s or can—under certain circumstances—even stop rolls completely. Reduced roll speed means minimal roll bouncing and significantly shorter settling times. The product design and soft, special materials ensure gentle contact with the roll and no damages to the roll or the roll handling equipment.

the braking pad shown on a winder deck
The Braking Pad shown on a winder deck.

Reduced roll speed and decreased roll bouncing means a significant increase in operator safety as well as the minimization of manual roll pushing. Notably, in high-speed applications such as winder decks, a combination of the MoveRoll Zero Energy Receiver and the MoveRoll Braking Pad achieves the biggest increase in work safety.

Hanna can attest to this. “The winder deck remains the one place in the mill where operator intervention is common. Even with automated decks, there are certain instances where operators must inspect roll ends, perform hardness tests, and manage improperly wound rolls,” he says. “Many of these decks are made of poured or sloped concrete as old as the mill itself. Roll speed can be excessive, and machinery damage is common. When we engineer brake pads into our systems, they control these speeds to extend equipment life and settle rolls on conveyors more quickly.”

HOW DO MOVEROLL BRAKING PADS WORK?

Each braking pad is made of a number of thin cushions (depending on length) designed to be positioned on the rolling surface and to stay in place without any attachment. The kinetic energy is reduced by special soft material placed inside the braking pad and air that exhausts out of the braking pad as the roll weight squeezes.

Figure 1 (A) shows the braking pad placed on the floor, acting as a barrier to reduce the speed of the paper roll. When reaching the braking pad, the paper roll goes over, initially collecting air on the front end of the pad that later will be released from the exhaust ports on the back of the pad (B). The air leaving the pad causes counter pressure in back that reduces the speed or stops the roll. When the roll has left the surface of the pad, the interior material returns to its previous form (C) and is ready for the next roll.

a figure this series illustrates how the braking
Figure 1: This series illustrates how the Braking Pad operates before (A), during (B), and after (C) engagement with the roll.

The MoveRoll Braking Pad works in various roll handling applications. For example, paper mills can place braking pads in front of slat or chain conveyors to slow rolls and reduce settling time. Similarly, braking pads are useful on different sections of ramps to reduce roll speed before the rolls impact on the stoppers. In situations where the roll speed is high—e.g., on winder decks—the pads are most effective in two separate rows; for example, in front and behind separation stoppers.

With standard and custom lengths, MoveRoll Braking Pads are available in two different versions: magnetic and non-magnetic bottom. The magnetic braking pad has a very thin layer of strong magnetic mat and is suitable for applications where the roll handling surface is metallic. Paper mills have used the non-magnetic version.

a roll approaches the zero energy receiver
A roll approaches the Zero-Energy Receiver.

In some cases, heavy rolls must be stopped completely, which requires another product. A mechanical receiver has been the most typical solution; however, mechanical receivers are often costly, require continuous maintenance, and in some applications can even damage the paper roll. In more serious cases, operator safety has been a challenge due to rolls bouncing back.

To resolve these issues, MoveRoll has created another patented product called the MoveRoll Zero Energy Receiver. Meant for low-frequency roll handling applications, the Zero Energy Receiver is equipped with self-inflating roll handling cushions. The material of the cushions is flexible and prevents rolls from hitting against the metal frame of the Zero Energy Receiver, avoiding roll damages. Notably, the Zero Energy Receiver does not need an energy source to absorb the kinetic energy of paper or board rolls.

As mentioned, traditionally, paper mills use steel stops, pneumatic stoppers, or mechanical receivers to catch rolls that come down ramps or sloped floors. These rolls move in an uncontrolled fashion and gain speed before they hit these inflexible stops, causing heavy bounceback. This results in a dangerous work environment, easily damaged rolls, and longer roll settling times than necessary.

In contrast, the soft cushions of the patented Zero Energy Receiver reduce the kinetic energy by, on average, more than 75 percent. This significantly lowers the risk that paper mill staff will get hit by or crushed between paper rolls.

In a typical installation using both the MoveRoll Braking Pad and the Zero-Energy Receiver, the braking pad has two functions. First, it reduces the kinetic energy of the roll before hitting the receiver; second, it prevents the paper rolls from bouncing back to the winder deck area.

“The combination of the brake pads and the zero-energy plate stop take energy out of the rolls when you need to,” says Hanna. “Both are self-inflating, so compressed air usage is zero. These products are very versatile. All paper mills are different, and we use them strategically to solve our clients’ roll handling problems.”

Jonis Mahmutllari is sales manager, Europe, for MoveRoll Oy. He can be reached at .