Note that code 2, silicon carbide-on-silicon
carbide, seals are not recommended for
steam-purged applications as the seal faces
can bind together - see Cleaning and
Sterilizing.
Pumps fitted with single seals require no
special installation but pumps must never be
run completely dry for more than 30
seconds, as this will cause excessive
heating of the seal faces. Use flushed seals
in pumps that need to run dry.
The
Flushed Mechanical Seals
fitted to
Hy~Line
and Ultima pumps are run with a
low-pressure liquid flush between the
primary mechanical seal and a lip seal to
form a barrier between the pump and the
atmosphere. This allows the pump to be
used for applications where the single seal
is unsuitable.
Flushed seals are used when:
• Pumped fluid changes state in contact
with air, e.g. crystallises, forms a film,
dries out or precipitates solids. The flush
dissolves and rinses away the small
amount of reside which could build up on
the edges of the seal faces
• Pumped fluid is close to its boiling point
e.g. water over 80°C (175°F). The
flushing fluid is used to cool the seal
faces.
• Pumped fluid is temperature sensitive and
degrades when heated by the shearing
action of the seal faces. The flushing fluid
is used to cool the seal faces.
• Pump must run “dry”, i.e. no liquid in pump
chamber.
• Pump is under high vacuum.
• A low pressure sterile barrier is required.
A low-pressure flushing fluid system
must be installed as follows:-
• Liquid must be compatible with the
pumped fluid; water is the most commonly
used liquid.
• Pressure shall typically be 0.5 bar (7 psi)
gauge. Maximum of 1.0bar (14.5 psi)
gauge.
• Temperature shall be maximum of 70ºC
(160ºF) for water, less for volatile liquids
(maximum 20ºC (68ºF) below boiling point
of liquid).
• Flow rate shall preferably be 2 to 3
litres/min. (0.5 to 0.75 US gal/min) per
seal.
• Flush fluid should be connected to flow in
at the lowest point on the seal housing
and out at the highest point to vent air
pockets.
• Pipework should be as shown in the
diagram (see figure 4a).
Page 10
Hy~Line
and
Ultima
Lobe Pumps
07/03
Figure 4:
Flushed
Single Seal
Summary of Contents for Hy-Line
Page 41: ...07 03 Page 39 Hy Line and Ultima Lobe Pumps 7 00 MODEL NUMBER BUILD CODE...
Page 43: ...07 03 Page 41 Hy Line and Ultima Lobe Pumps 8 01 PARTS LIST...
Page 44: ...Page 42 Hy Line and Ultima Lobe Pumps 07 03 8 01 PARTS LIST CONTENTS OF KITS...
Page 45: ...Page 43 Hy Line and Ultima Lobe Pumps 07 03 8 02 Hy Line EXPLODED DIAGRAM...
Page 46: ...07 03 Page 44 Hy Line and Ultima Lobe Pumps 8 03 Ultima EXPLODED DIAGRAM...
Page 47: ...07 03 Page 45 Hy Line and Ultima Lobe Pumps 8 04 Hy Line 3 Size SECTIONAL VIEW...