6 Commissioning/Start-up/Shutdown
38 of 80
Vitacast / Vitacast Bloc
CAUTION
Risk of freezing during prolonged pump shutdown periods
Damage to the pump!
▷
Drain the pump and the cooling/heating chambers (if any) or otherwise protect
them against freezing.
6.1.7 Seal supply system
6.1.7.1 Application
In order to function properly, the mechanical seals require a flushing liquid. The
flushing liquid completely fills the space between the inboard and the outboard
mechanical seal.
6.1.7.2 Requirements to be met by the seal supply system
Pipework routing
requirements
When routing pipework and flexible tubing, prevent any high points or ensure that
high points can be vented separately to prevent dry running of the mechanical seal.
The connecting pipes between the main pipe and the pump must be routed with a
continuously rising slope to assure self-venting of the pipe and the mechanical seal,
respectively.
6.1.7.3 Types of seal supply systems
Which of the two types of seal supply systems is used depends on the mechanical
seal:
6.1.7.3.1 Quench liquid
6.1.7.3.1.1 Applications
A quench liquid is used in the following cases:
▪
Where a single mechanical seal without supportive measures would not work at
all or unsatisfactorily.
▪
Where a double mechanical seal design with pressurised barrier fluid is not
required.
6.1.7.3.1.2 Quench liquid requirements
The quench liquid should preferably form a solution with the fluid handled and be
environmentally compatible.
Typical quench liquids
▪
Water with a conductivity of 100 - 800 µS/cm
▪
Water/glycol mixture
▪
Glycerine
8)
The quench liquid should be supplied to the mechanical seals unpressurised (at
atmospheric pressure), if possible. Positive pressures of up to 0.5 bar are acceptable.
The one-way quench supply should be adjusted to a constant flow ≥ 0.4 l/min.
Periodically check the quench liquid for contamination (replace quench liquid and
clean quench system if necessary).
6.1.7.3.1.3 Applications
For seal types T and H, operating mode BQ
8)
Make sure the circulation line diameter is ≥ ¼".
