The Rho-meter system is recommended for either hard paper rolls, or for use on films and plastics. It will not do damage to a wound roll and has a preset amount of impact.


The Rho-Meter measures the peak force generated by contact of a striker moving at a known velocity against a surface of unknown hardness. During a collision between two objects, both experience a common and opposite force. This reactive force, or "impulse force", rises from zero to a maximum value then returns to zero. The area under a plotted force-time curve is called "impulse" and is measured in units of pound-seconds. This "impulse" determines the "magnitude of the blow" and is exactly equal to the net change in momentum of either body. Dividing the impulse by the contact time results in an average force during collision. Peak forces are measured by a high accuracy accelerometer capable of withstanding severe shocks and adverse enviroments. The accelerometer is rigidly mounted on the striker to measure the peak acceleration at collision. A cantilever spring system with a straight line motion accelerates the striker mass to the desired constant velocity. The mechanical components of the Rho-Meter are adjusted to deliver an impulse of approximately 0.06 pound-second on impact. The peak force measured by the accelerometer is transfered to a holding circuit and displayed on the digital display. Greater hardness of the test object results in larger peak force and more peak acceleration.






Rho-Meter: (2) Sealed Lead Acid rechargeable batteries,
24 volt (25v nominal) D.C.
Recharger Power: 115 volt A.C. 50/60 cycle (230 volt A.C. 50/60 cycle is available)
Recharger Output: 3-stage constant voltage 28 volt D.C.
Reading Accuracy: Repetitive ± 1 digit (± 1 Rho) to within ± 1 division of hardness standard (2 Rhos)
Weights: Rho-Meter 7.5 lbs (3.40 KG)
Carrying Case 7.8 lbs (3.54 KG)
Hardness Standard 9.5 lbs. (4.31 KG)
Dimensions: Recharger 1.25 lbs. (0.57 KG)




Technical Help

Welcome to the Tech support Page for the Bel-2000 and Rhometer.
Check out our FAQ page for questions about our units.

You may also email our BEL-2000 Department with questions not found on our FAQ page.
If you are looking for accessories, you'll find them HERE.