Home

Foundations™ Learning Center

Foundations Learning Center

Below is a list of all the blog posts you are posting that your
visitors might be interested in...

Conveyor Belt Cleaner Tensioning Systems/Devices

Blade-to-belt cleaning pressure is maintained by a tensioning device. These tensioners range in sophistication from concrete block counterweights and locking collars to torque storage couplings and engineered air-spring systems plumbed to the plant’s preferences.

Spring tensioners extend from a head cute of belt conveyor.
More sophisticated tensioning systems include engineered air-spring systems plumbed to the plant's compressed-air supply.

All tensioning systems should be designed to allow passage of mechanical splices and other obstructions. Tensioners should be self-relieving to minimize risk of injury to personnel or equipment if the blades are “pulled through” by obstructions or holes in the belt.

A precleaner is shown on a head pulley.
Tensioning systems should allow the cleaning edge to relieve away from the belt in order to allow passage of mechanical spices and other obstructions.

A tensioning device should be designed to be compatible with the cleaner in order to provide a consistent blade-to-belt pressure throughout the life of the blade. When cleaner adjustment and re-tensioning are required, the tensioner should allow this maintenance to be performed simply, without requiring tools or more than one service worker.

Some cleaners use the resilience of a urethane blade, which compressed and locked into position, to supply the cleaning pressure. When installed, these blades are deflected by being forced against the belt. As the blade wears, it “stands taller” to maintain cleaning pressure. Because the blade itself supplies both cleaning pressure and shock-absorbing capacity, the cleaner does not need a conventional tensioner. Instead, the blade assembly is forced against the belt, and the mainframe is locked into position, slightly compressing the blades to set the initial blade-to-belt pressure.

A secondary cleaner is shown made of urethane.
Some cleaners use the resilience of a urethane balde to supply the cleaning pressure.

Linear or Radial Adjustment

There are competing theories for belt cleaner adjustment: there are linearly adjusted cleaners that are pushed up (in a line) against the belt, and radially-adjust cleaners that are installed with a mainframe as an axis and rotated into position.

A secondary cleaner is shown made of urethane.
Lineraly-adjusted cleaners are pushed up (in a line) against the belt; radially-adjusted cleaners are rotated into position with the mainframe as an axis.

Radially-adjusted cleaners have several practical advantages over the linear design. They are easier to install, can be adjusted from one side of the belt, and can more readily rotate away from the belt to absorb the shock inherent in belt motion and splice passage.

Linearly-adjusted cleaners generally required access to both sides to provide even adjustment. Because of this, the tensioners for these cleaners often have some form of powered adjustment, such as an air bag, that can be remotely controlled. Linear tensioners maintain a constant-cleaning angle as the blade wears and can be designed to allow for easy withdrawal of the cleaner for maintenance without removing the tensioner.

2 secondary cleaners are installed under the belt.
Linearly-adjusted cleaners generally require access to both sides of the belt to provide even adjustment.

In addition, some hybrid systems incorporate vertical tensioning with a radial relief mechanism. Maintaining the angle of the blades against the belt is important for ensuring effective cleaning. If the angle of contact is altered by blade wear, cleaner performance will similarly “decay.” A well-designed belt cleaner must control the cleaning angle across its wear-life.

A secondary cleaner with a spring-style tensioner.
Some hybrid systems incorporate vertical tensioning with a radial relief mechanism.

Cleaner Installation

A critical ingredient in the performance of any belt-cleaning system is its installation. Improper installation will have an adverse effect on how the cleaner performs; it will reduce blade-life and cleaning efficiency. The installation instructions from the manufacturer should be closely followed. Considerations affecting the installation position of a belt cleaner include:

  1. Cleaner design
  2. Tensioner and mounting requirements
  3. Bolting or welding the cleaner in place
  4. Installation on chutewall or hung from stringer
  5. Position of conveyor structural beams, bearings, and drives

Regardless of the brand of belt cleaner, the critical factor in cleaner installation is that the cleaner support frame be installed at the correct distance from the surface of the belt. Placing the cleaner at the proper distance from the belt helps avoid “pull through” problems, in which the belt pulls the cleaner into the belt and all the way around into an inverted position, which usually results in a bent mainframe. Maintaining the proper dimension places the blades at the correct angle of attack against the belt for the best cleaning, proper blade wear, and longest life. The correct distance will be different from cleaner style to cleaner style.

A tape measure is held to show the distance between the belt and the mainframe.
Placing the cleaner at the proper distance from the belt helps avoid “pull through,” in which the belt pulls the cleaner all the way around into an inverted position, which usually results in a bent mainframe.

It is strongly recommended that the manufacturer install and maintain the belt cleaners on both new and retrofit applications, because most performance problems with new belt-cleaner systems are due first to improper installation and second a lack of maintenance. Using the manufacturer (or manufacturer-approved contractors) for installation makes certain of proper installation and continued performance.

Topics: Material Carryback & Belt Cleaning

Leave Comment