BITZER Kühlmaschinenbau GmbH
Hermetic Compact Screw Compressors
Hermetic Screw Compressors VSK31 / VSK41
The hermetic compact screws complete the compressor screw programme in the lower capacity spectrum. They are suited for insertion into factory finished air conditioning units, liquid chiller units and in particular also for the air conditioning of railway carriages.
The space saving design with integrated oil separator and reservoir enables the simplest installation. With their small height, low weight and very smooth running over a wide speed range, they already meet today the increasing demands of confined roof and under floor installations.
The deciding features:
- Simple and robust construction
- Hermetically sealed by welding
- Low weight
- Small space requirement
- Low noise and vibration levels
- Optimised design for R134a
- Ester oil change
- Generously dimensioned roller bearings, giving high reliability and long life
- Integrated oil separator / oil filter
- Build-in check valve (VSK41)
- Internal pressure relief valve
- Suction gas cooled motor – direct drive without gears
- Motor protection device with
- thermal PTC monitoring
- manual reset
- phase sequence monitoring
- High capacity and efficiency due t
- optimised rotor profile (5:6)
- high motor efficiency
- precise machining
- Capacity control
- stepless with variable speed (frequency converter)
- VSK41 and VSK3162 alternative with integrated mechanical regulator (capacity regulator)
- Terminal box IP66 (VSK31… with small terminal box IP65)
Design Safety
Approval according to the EC Pressure Equipment Directive 97/23/EC Maximum allowable pressure 25 bar.
Capacity Control and Start Unloading
For the series VSK41 a new form of regulating system has been developed (accessory). The basic principle corresponds to that of a control slide of industrial compressors. Thereby the displacement is reduced by moving the suction side sealing controur. The control unit is so designed that it does not reduce the stability of the compressor housing. The gaps between the rotors and the housing thus remain within tight tolerances, even with high temperatures. This measure is an important stage of development for a good overall efficiency of smaller screw compressors, due to the higher demands on precision.
