OSHA Extends Comment Period for Proposed Crane Operator Rule

Crusher Blockage Clearance Apparatus Speeds Up Process

Sat September 15, 2007 - National Edition
CEG



Screen Machine Industries Inc. has designed manufactured track mounted impact crushers that improve safety and productivity.

The new “Crusher Blockage Clearance Apparatus” feature has reduced the frequency for which laborers and machinery must clear bridged material in order to resume production. The multiple applications of oversize rock and c&d materials with which impact crushers have contended, have plagued job site production results since portable impact crushing began, according to Screen Machine.

The Problem

The wide range of wheel loaders and excavators that load material to all brands of tracked portable crushers routinely deliver oversized or non-aligned material that clogs or bridges the inlet entrance to the crushing chamber.

The Consequence

Job site crushing projects are brought to a halt due to material bridging within the crusher chamber inlet opening. Production stops while the crushing rotor and engine of the machinery are shut down so that personnel with tools can safely clear the bridged material.

Typically, pry bars, slings and hydraulic or pneumatic hammers are utilized to free the bridged material so that production may continue.

Common to this process is the loss of 30 to 90 minutes per episode along with the loss of hundreds of tons of productivity — depending upon the severity.

Safety of job site personnel also is a concern in this situation. Efforts to avoid the safety related concerns of manually clearing this bridging setback lead to further productivity woes.

Loader operators will either slow the feed of their crushers to 50 to 75 percent of their “rated capacity or spend an excessive amount of time pre-breaking the material into smaller sizes in an effort to avoid repeat bridging issues.

Both methods significantly slow production output.

The Solution

Screen Machine Industries Inc. has designed a remote controlled pivoting arrangement between the chamber lid and the chamber housing. With the push of a button, the lifting lid of the chamber will raise and lower vertically relative to the housing opening without having to shut-down the machine.

This cycle creates a temporary increase in height permitting material that has bridged or obstructed the crusher opening to pass freely through the chamber, preventing costly down time and lost productivity, according to the manufacturer.