ASTM D4179, ASTM D6175, ASTM D7084
The crush strength is the resistance of a solid to compression, a property of paramount importance not only for industrial catalysts, but also for ceramics, pharmaceutical tablets and many other solid materials. In the case of catalysts, it is noteworthy that many plant shutdowns occur due to mechanical failure of the catalyst (and not due to its loss of activity). The whole CRUSH series is compliant with CE specifications.
CRUSH-BK, compliant with ASTM standards ASTM D4179, ASTM D6175 and ASTM D7084 (on Crush-BK 500Kg), is an instrument for measuring the crush strength of solid materials which have a regular, or almost regular, geometrical shape (like spheres, cylinders, rings and similar). They can in range in size from 1 to 20mm.
- CRUSH-BK allows to make both single pellet (ASTM D4179 and ASTM D6175) and bulk measurements (ASTM D7084) with the same instrument and in its standard configurations features a maximum load.
- CRUSH-SP, applying much lower loads (30 kg max, different loads available on request), is recommended when bulk measurements are
not required and the pellets under examination are not very resistant.
The maximum load applicable of CRUSH-BK and CRUSH SP can vary according to customer’s requirements (specialists at MaTec can assist customers to select the most suitable instrument).
CRUSH-BK is based on a dynamometer which measures the force applied progressively to the solid sample during the advancement of a piston. The force applied increases until the solid breaks and collapses into small pieces and, eventually, turns to powder. The corresponding value of the collapsing force is defined as crush strength.
Touch screen display
Both CRUSH-BK and CRUSH-SP feature a touch screen display to operate the instrument and visualize the crush peak load (crush strength in Newton).
Built-in computer and Data-treatment software
CRUSH-BK/PC and CRUSH-SP/PC are the most advanced configurations of the Crush series instruments, featuring a built-in computer and data-treatment software.
CRUSH-BK and CRUSH-SP are dynamometers of general use for compression measurements. As far as catalysts are concerned, the ASTM standard methods ASTM D4179 and ASTM D6175 are recommended. ASTM D4179 refers to tableted pellets, which can be measured in either axial or radial way. As the axial crush strength is much higher, it is not representative of the catalyst behavior in the reactor, therefore the radial crush strength must be measured for industrial purposes (the type of crush strength measured must always be specified).
ASTM D6175 procedure refers to extrudates (the radial measurement can only be performed in this case). The radial crush strength is usually expressed in kg/mm or Newton/mm.
Bulk crush strength measurements are performed by standard method ASTM D7084. A faster and simplified procedure developed by MaTec is available to our customers.
The official text describing the methods can be found at www.astm.org
When the catalyst does not require activation, the crush test should be conducted on fresh dried samples.
When the catalyst has to be activated in the reactor, only measurements on activated samples are significant.
- Pressure drop increase in axial reactors.
- Bypass formation in radial reactors.
Single-pellet radial or, for irregularly shaped particles, bulk crush strength must be measured for any catalyst used in fixed-bed and trickle-bed reactors. The average value of the force required to break the pellets is usually specified for single-pellet crush strength.
For bulk crush strength, either the pressure giving 1% fines (ASTM D7084), or the percentage of fines formed under the pressure of 23 bar (MaTec procedure) are specified.
Alumina spheres | 7 kg min
LTS pellets* | 5 kg min
HTS pellets* | 10 kg min
Methanol pellets* | 8 kg min
Formaldehyde rings | 2 kg min
Hydrotreating extrudates | 3 kg/mm min
Styrene extrudates | 2 kg/mm min
Alumina spheres | 10% max
Hydrotreating extrudates | 5% max
Alumina extrudates | 15% max
Active carbon granules | 20% max
Ammonia (prereduced) granule | 1% max
**Ma Tec procedure
Size (W x H x D)
310 x 650 x 460 mm
White and black
Piston advancement rate
External display port
HDMI (CRUSH-BK/PC, CRUSH-SP/PC)
Particle size range
500 kg (different loads available on request)
30 kg (different loads available on request)
Speed of measurement
Bulk (CRUSH-BK only)
Single pellet (average of 50 pellets)
Bulk (average of 5 measurements)