2.5
ALIGNMENT
Alignment of the pump and driver is of extreme
importance for trouble-free mechanical operation.
EBSRAY mounted pumpsets are accurately aligned at
the factory. To ensure this has been maintained during
transit, alignment MUST BE checked once before startup
and again after the pumpset has been run under actual
operating conditions. NOTE: The following procedures
are typical only and reference should be made to data for
specific coupling types.
ANGULAR MISALIGNMENT as shown in Fig.1 should
be corrected before eccentricity. Refer Fig.3; Use feeler
gauge reading at 90o intervals, the amount of correction
necessary can be easily determined to bring shaft axes
in line.
Misalignment due to ECCENTRICITY as shown in Fig 2
can now be corrected. Refer Fig 4, adjustment by use of
shims under the driver or pump will effectively correct
error in the vertical plane. Movement of Pump or Driver
horizontally will correct error in the horizontal plane.
Note:
If both coupling halves are of identical diameter
concentricity may be checked with a straight edge at 90
o
intervals.
SECTION 3 - OPERATION
3.1
DESCRIPTION
The EBSRAY Internal Gear principle is based upon the
use of an Outer Rotor 'A', idler gear, termed Inner Rotor
'B' and a crescent shaped spacer 'C' which is cast
integral with the Cover. Thus only two moving parts fulfil
this efficient displacement cycle. Power is applied to the
Outer Rotor 'A' and transmitted to the meshing idler or
Inner Rotor 'B'. The rotor teeth cells which are not
involved in the meshing cycle are sealed by the crescent
'C', Body and Cover. (Refer Fig.5)
3.2
PUMPING PRINCIPLE
When rotation is started there is an increase in cell
volume as the teeth come out of mesh. This creates a
partial vacuum and the pressure differential thus created
initiates movement of the liquid through the inlet port 'D',
filling the teeth cells of the two displacement rotors.
When the tooth meshing withdrawal cycle is complete
and the tooth cell volume is filled with liquid, transfer to
the pressure or discharge side is effected as the liquid is
carried past the crescent sealing member 'C'. This
sealing crescent establishes a labyrinth between the high
and low pressure sides, minimising fluid slip. When the
teeth mesh on the pressure side, the liquid is forced from
the teeth cells and flows through the discharge port 'E'.
A noteworthy feature of this simple pump principle is the
absence of high tooth contact pressures when compared
with conventional gear pumps, many of which employ
costly external timing gears to minimise tooth wear. The
Inner Rotor 'B', or idler remains in almost hydraulic
balance requiring only minimal torsional load to
effectively follow the driving Outer Rotor.
Figure 5
3.3
APPLICATIONS
The field of applications for Internal Gear rotary positive
displacement pumps is extensive. These pumps are
used to handle many kinds of liquids over a wide range
of capacities and pressures, associated with viscous or
non-viscous, hot or cold and corrosive or non-corrosive
conditions. Accordingly material, speed and power
specifications vary and it is important to use such
equipment strictly adhering to the manufacturers'
recommendations
3
Summary of Contents for MD Series
Page 12: ...12 NOTES...
