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Testing Principle
The device is loaded by gently pressing the tip of the impact plunger against a solid surface, it then slides out of the
housing until it is fully extended. The plunger is then pressed against the surface to be tested, this fires a percussion
weight against the rear of the plunger and rebounds.
The rebound is dependant upon the the hardness of the surface under test, the harder the surface the higher the
rebound and visa versa. The maximum height of rebound is recoreded on a scale which represents the rebound as a
percentage of the forward movement of the percussion weight. The rebound number obtained with the HT 225A
can be converted to a compressive strength value via conversion tables contained in the user manual. The conversion varies with the angle of test, therefor values must be corrected for those other than the standard horizontal
direction. The various angular corrections are also shown in a table in the user manual.
Specifications for HT225A
| 1. |
Normal Kinetic Energy : |
2.207J (0.225kgf.m) |
| 2. |
Flip tension spring rigidity: |
7.84N (0.80kgf)/cm |
| 3. |
Punch advance for imapact hammer: |
75mm |
| 4. |
Impact surface hardness value between impact hammer and rod: |
HRC59-63 |
| 5. |
Maximum breakout friction of pointer system: |
0.49 - 0.78N (50-80g) |
| 6. |
Meanvalue of steel-anvil rating of concrete test hammer: |
80+-2 |
| 7. |
Dimension: |
60x280mm |
| 8. |
Weight: |
1kg |
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