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Pump NB/FB/WP/SM/F
Version: 27216 - E
Schmalenberger GmbH + Co. KG
D-72072 Tübingen / Germany
7.7
Sealing medium
The GLRDs require a sealing fluid to retain proper function. The purpose of the fluid is to
divert heat from friction and to prevent the product from entering into the sealing gap. The
sealing fluid fills up the space between the product side and atmosphere side GLRD.
Requirements for sealing fluid:
•
Compatibility with the medium being sealed off
•
Suitability in terms of corrosion resistance of all parts in contact
•
Free of solids
•
Must not tend to form accumulations
•
Good lubrication properties
•
High specific heat capacity
•
High evaporation temperature
•
Environmentally friendly
For SKS with sealing pressure we recommend:
Clean water with a low hardness rating in a closed circuit
For SKS without sealing pressure we recommend:
Low alloy mineral oils; i.e. without EP (high-pressure) additives that tend for form
accumulations, thin (max. rating 46 according to ISO VG viscosity class). For example
Total CIRKAN RO 32 or
•
Cool emulsion (coolant with at least 8% oil)
•
Water/glycol mixture
The sealing medium must not damage the sealing materials either chemically (for example
corrosion, embrittlement) or physically (accumulations, etc.).
7.8
GLRD Materials
The materials pairing of GLRD as a standard design (SiC/SiC + Viton ) may deviate from
what is delivered! Note your pump specification. Usually the pump-side GLRD is designed
medium-dependently.
7.9
Emissions, Personal Protection
A GLRD is a dynamic seal which cannot be leak-free for physical and technical reasons.
The seal design, manufacturing tolerances, operating states and how smoothly the
machine runs, etc. largely determine the leakage quantity. A GLRD has little leakage
compared to other dynamic sealing systems.
The leakage may be in the form of a liquid or gas. How aggressive the leak is depends on
the medium being sealed off.
If the seal fails, the medium being sealed off may spray out. The operator must arrange for
and monitor preventive measures to protect against personal injury and damage to the
environment such as putting spray protection in place, wearing safety goggles, etc., and
must properly dispose of leaked materials.
GLRD leak rates:
GLRD leakage must be selectively diverted and safely disposed of.
