HSO 2024 to HSO 2035 Installation, Operation and Maintenance Manual
Issue 1.2 : 03/10
Publication 2-119
Page 13 of 94
3.
General Description
The J & E Hall International HSO 2000 series of open drive compressors
form part of the HallScrew family of positive displacement, oil injected,
single screw compressors.
These compressors have been specially developed for refrigeration, air
conditioning and heat pump applications, and can be applied to single
stage and multi-stage systems using all normal refrigerants as well as
many other process gases.
3.1.
Main Features
•
For use with R717 (ammonia), R22, R404a, R507A, R134a,
R407c, R410a and R23.
•
Designed and tested to international standards.
•
Robust construction.
•
Improved machine clearance control for maximum efficiency.
•
Oil injected for maximum reliability.
•
Balanced loading on main bearings for maximum bearing
life.
•
Enhanced slide valve geometry for capacity modulation with
minimum loss of efficiency. Infinite adjustment between
maximum (100 %) and minimum load (nominal 10 %).
•
Economiser facility provided to improve operating efficiency,
especially at high compression ratios.
For further information refer to publication 2-129 Economiser
Facility For HallScrew Compressors.
•
Anti-clockwise rotation looking on the motor (driven) end.
Intermediate gearbox required for gas engine drive.
3.2.
Construction
The motion work, i.e. that part of the machine which performs the
compression function, consists of three rotating parts; there are no
eccentric or reciprocating motions. These fundamental components
comprise the cylindrical main rotor in which are formed six-start, helically
grooved screw threads with a spherical (hourglass) root form. The main
rotor meshes with two identical toothed wheels each having eleven teeth.
These wheels (or 'star rotors' as they are called owing to their shape), are
made from a special synthetic material. They are located in a single
plane diametrically opposite each other on either side of the main rotor
with their axes at right-angles to the main rotor axis. As the main rotor
turns, it imparts a freely rotating motion to the star rotors.
The star rotors are supported by metal backings which are cast in one-
piece with the star rotor shafts. Although they are located in place on
their backings, the stars are allowed to 'float' a small amount in a
rotational sense. This floating action, combined with the low inertia and
negligible power transmission between the main rotor and star rotors,
effectively absorbs any minute vibrations of the star/main rotor
combination. The star rotor shafts are supported at each end by taper
roller bearings.
The main rotor is a dynamically balanced component, manufactured from
cast-iron, keyed to the steel mainshaft which runs in rolling element main
bearings. Where the shaft emerges from the casing, leakage of oil or
refrigerant is effectively prevented by a specially designed mechanical
seal.
