Thermal Growth Monitoring | Using “CAD” for PERMALIGN Bracket Design and Installation

March 19, 2012

PERMALIGN is the world’s leading machinery positional change measurement system. Since 1986, it has proven itself as the most accurate and dependable solution for thermal growth measurement. PERMALIGN is a laser based system capable of detecting and accurately measuring both relative or absolute movement, depending on the prisms and setups selected. To this day, it remains unequalled in ease of use and precision of measurement.

A great majority of the PERMALIGN applications involve installing two roof prisms and two laser monitors on the inboard bearing housing of each machine.  By measuring the bearing housing movement, the alignment change can be determined from the relative movement of the machines.  The preferred method of installation is to drill and tap a 10-32 × ½” deep hole into some part of the machine that is directly connected to the bearing housing as shown below.

Permalign Monitoring Setup
Sometimes, this is not possible. The next solution is to construct a strong bracket (usually of 5/8″ thick steel plate) that can be physically attached to the bearing housing.  This usually involves temporarily replacing a housing bolt with a longer bolt that allows the bracket to be “sandwiched” to the machine as shown below.

Angle Bracket
Sometimes, the presence of obstructions (proximity probes, electrical conduit, piping) can interfere with the positioning of the brackets and the PERMALIGN components.  When designing brackets for these situations, the fastest and easiest method is to take advantage of CAD.  I am not referring to “Computer Aided Design”, but something far more effective in the field – “Cardboard Aided Design”!

Get a piece of cardboard, a pair of scissors and cut out a template for the bracket that you will need.  You can bend it in any shape you wish and mark your mounting points with a marker.  Need to make a design change?  Just cut it to change the dimension!  As shown below, this precision engineered template was crafted with a pocket knife.CAD Template

Below is the template next to the fabricated piece.  The template provides an easy to follow map for building the bracket.  PERMALIGN brackets are usually torch cut in the field, ground and welded together.  The design emphasis is for it to be STRONG, not pretty!
 
Angle Bracket - CADTemplate

Below is the final result.  The cardboard template allows the design to be checked prior to fabrication and installation. 
 Final Setup

 

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