Search

Testing the XPert Weigh Box for Vibration

If you’re weighing potent fine powders using an analytical balance, the XPert Weigh Box offers a physical barrier to protect you. But how does it weigh in on keeping your analytical balance stable? Labconco put it to the test.

The built-in exhaust blower in the XPert Weigh Box creates vibration. Since analytical balancesmay be sensitive to motion disturbance, Labconco engineers tested various methods to dampening the vibration on the box’s work surface.
 
First, to establish a baseline, they measured the displacement level with the blower off. Five measurements were taken on the work surface and the average displacement was 1.4 micrometers. Next they took a baseline average when measured with the blower off and on a 2” thick marble slab supported by isolator pads. The average was a similar 1.3
micrometers.
 
With the blower at full speed, the average displacement level measured directly on the work surface was 5.3 micrometers. Yet, with the blower at full speed, the average displacement level measured on a marble slab supported by isolator pads was a mere 1.5 micrometers — very close to the same measurement with the blower off! When an analytical balance was added to the marble slab, readings remained stable to five decimal places.
 
Labconco engineers tested other four other anti-vibration materials besides marble. Plastic rubber and thermoplastic foam failed to lower the vibration levels significantly further than the marble slab. A chart summarizes the testing is shown below.
 
Conclusion: In this case, old “technology” (marble slabs) work best. XPert Weigh Boxes come standard with a Balance Vibration Isolator, which consists of a 2” marble Slab, four isolator pads and a stainless steel protector cover. This same Balance Vibration Isolator is available as an accessory, Catalog #5234600, for Precise and Protector Glove Boxes.