ACCESSORIES
The Marathon
®
CP-8 Cryopump has been designed to allow its utility ports to be reconfigured in
the field by the installation of various accessory options. All CP-8 pumps have three 1.33" O.D.
metal seal utility ports in the base of the vacuum enclosure as shown in Figure 3. Each of these
ports can be adapted to a specific function by attaching the appropriate accessory. Any
accessory may be mounted to any utility port. The accessory must be properly oriented to avoid
interference. The available accessories are:
Part Number
Rupture disc, 124 kPa (18 psia) 260022A2
Rupture disc, elbow 262900B1
Blank for 1.33" O.D. accessory port 260021A2
Pumpout/nitrogen purge adapter 266708A01
Standard single silicon diode temperature sensor,
4 pin
253995C2
Optional dual silicon diode temperature sensor, 10
pin, for use with Marathon
®
Cryopump Controller
(MCC)
266686A1
Hydrogen vapor bulb temperature sensor
(bottom mount)
263387C
Relief valve, elbow 262889A2
Blanket heater, 250 watts, 208 V, 1~, insulated,
130° thermostat, with mounting springs
267358C
HIGH PRESSURE GAS HAZARD. A relief valve or a rupture disc must always
be installed on a cryopump.
The cryopump will be preconfigured at the factory to customer’s requirements so no assembly
of components is necessary prior to installation. However, it is easy to rearrange accessories in
the utility ports or to install additional accessories at a later date.
Installation
All accessories mount to the 1.33" utility ports. However, specific mounting instructions follow
for installing the Pumpout/Nitrogen Purge Adapter, the Silicon Diode and the Hydrogen Vapor
Bulb Temperature Sensors.
To mount an accessory to a utility port, use a 9/64" hex key wrench. Hold the accessory and a
new copper gasket in place on the utility port. Fasten the flange to the tapped port with six flat
washers, lock washers, and #8-32UNC x 5/8" long hex socket head cap screws. Tighten the
screws with the wrench.
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