Parallel Compounding With Oil Level Controllers - Bitzer KT-600-4 Manual Del Usuario

4.3 Parallel compounding with oil level controllers

Oil level controllers (with oil separator and oil reservoir) are for universal use. They should be given preference in
the following applications:
• Parallel connection of > 3 compressors
• Compressors of different capacities and / or with capacity control (including speed-controlled compressors)
• Parallel connection of compressors operated at different suction pressures
• Systems which tend to migrate large amounts of oil to the low pressure side (e.g. low flow velocity at part load;
critical limit depends on the operating conditions and the refrigerant)
• Branched systems with long lines and large amounts of refrigerant
• Compressors of different capacities and / or different lubrication systems (centrifugal lubrication / pump lubrica-
tion)
• R744 compressors (sub- and transcritical applications, systems with parallel compression)
The oil level in the compressor is actively monitored and topped up when required. There are different designs:
• Mechanical oil level controllers with a combination of float and valve systems
• Electronic oil level controllers with float or sensor technology (e.g.: see chapter Oil level controller OLM-IQ, page
46 ). The oil supply is controlled indirectly via an integrated or external solenoid valve. This version simultan-
eously allows minimum level monitoring of the oil level and should therefore be given preference.
Oil level controllers are mounted along with the relevant adaptors directly on the sight glass connection; in doing
so, the available sight glass is removed ( see page 44 ).
General requirements and recommendations
Systems equipped with oil level controllers require an oil separator that provides the oil to be distributed. In general,
a common oil separator is used ( see page 40 ).
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