Proceq Equotip 550 Operating Instructions Manual page 12

3.3 Measuring Methods
Equotip 550 family of instruments is capable of accepting three diffrent
test methods using a single indicating unit.
3.3.1 Equotip Leeb
3.3.1.1 Test Principle
Connection cable – 4 pole
Sensor of impact device with
ID ROM
Support ring
Figure 10: Schematic View of a Leeb Impact Device
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During measurement with Equotip 550 impact devices (D, DL, DC, C,
G, S, and E); an impact body with a ball indenter is launched by spring
energy against the sample to be measured, and then rebounds. Before
and after the impact, a permanent magnet inside the impact body passes
through a coil in which a voltage signal is induced by the forwards and
backwards movement. This induction signal behaves proportionally to
the velocities. The ratio of the rebound velocity v
multiplied by 1000 yields the hardness value HL (Leeb hardness). HL is a
direct measure of the hardness. The third resp. fourth letter of the HL unit
Release button
refers to the impact device HLD  D impact device.
Loading tube
Equotip Leeb U
Although the Equotip Leeb Impact Device U is constructed differently to
simplify the measurement process, the underlying principle is the same.
Impact Spring
Catch chuck
Guide tube
Figure 11: Equotip Leeb U Impact Device
Existing Parotester impact devices type U are fully supported by the
Equotip 550. Typ P and PG impact devices can be still used, but the unit
Impact Body
is shown as HLU although it would be actually LP resp. LPG.
v
r
HL = ·1000
v
i
NOTE! HLU values can be directly compared to LU on exist-
ing Parotester instruments.
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Table of Contents
to the impact velocity v
i
r
© 2016 Proceq SA