Instruction manual

High Throughput Diffusion Pumps
16
DRAFT 12/23/04
Quick Cool Coil Connection
The Quick Cool coil at the boiler plate must be con-
nected to an open drain and the feed line must be con-
trolled by a separate water 3-way valve: open, closed,
and vented to the atmosphere. The drain must be below
the boiler level so that it is drained completely when the
Quick Cool coil water supply is shut off and the pump is
operating.
Obtaining High Vacuum on the NHS-35
When operating at low pressures (below 1x10
−
6
Torr), the
ultimate pressure can be lowered by bypassing the por-
tion of the cooling coils located at the bend of the foreline
as shown in Figure 9 on page 12. This procedure raises
the temperature of the foreline and provides additional
degassing of the fluid returning to the boiler, thus making
lower pressures possible.
NOTE This configuration decreases the
maximum throughput capacity of
the pump. Use this cooling
configuration only if the pump is
not meant to operate near the high
pressure end of its operating range.