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Рис. 4.
TMP design
arrangement with a hybrid flow
channel
TMPs with a variable flow and
without stator wheels have been designed.
This allows pumping gases with solid
macro particles. It is very important
for various sputtering units. One of the
pump modifications is shown in Fig. 3,
b
.
A peculiar feature of this design is a
combination of rotor wheels with alternating
axial and radial gas flows in the pump flow
channel. As a result, the efficiency of each
stage is increased.
TMP dimensions can be reduced if the
rotor wheels with a radial gas flow are
positioned on the pressure side (Fig. 4).
The research demonstrates that this
design arrangement has significant possibilities, especially with the multi
parametric optimization of TMP main characteristics.
The pressures ratio can be increased without increasing the pump
dimensions, if TMP axial stages and a cylindrical molecular vacuum pump
(MVP) unit are coupled in the flow channel.
In Fig. 5 TMNG-500 (variant 1) and TMNG-450 (variant 2) are
presented in comparison. TMNG-500 flow channel contains a conventional
set of both the axial rotor and stator blade wheels; in TMNG-450 it contains
blocks of the axial blade wheels and a cylindrical molecular pump with
helical channels in the pump casing. The shaft of these pumps is mounted
onto two radial and one axial aerostatic bearings.
TMNG-500 development was determined by the need to verify the
data for the efficiency of the hybrid flow channel designs and to estimate
manufacturing hours compared to TMN-450 pump, the flow channel of
which contains both the axial stages and molecular stages unit.
After comparing the mass produced vehicles it was established that with
25% increase in the agility reference value, both the volume and mass of
TMNG-500 pump grow by 20% and 6%, correspondingly compared to
TMNG-450 pump. Apart from that, according to the Special Design and
Engineering bureau
Vector
the production costs of these models include 862
(TMNG-500) and 950 (TMNG-450) standard hours, correspondingly. All
of this testifies to the superiority of the hybrid flow channel pumps, as they
possess the improved dimensional characteristics accounting for a certain
complexity in manufacturing. This is also confirmed by the sustained trend
of the world’s leading manufacturers to increase the number of vacuum
TMP with the hybrid flow channel (with the axial and molecular stages)
[4–8].
6
ISSN 0236-3941. HERALD of the BMSTU. Series Mechanical Engineering. 2014. No. 5