RH CGS-240, Manual

Page: 62 / 148

Subsystems
CGS-240 Manual 6/15/2021
Page 62 of 148
6.2.8 VENT VALVE, SOL 2
The vent valve, SOL 2, is used to vent pressure from the saturator
during shutdown and whenever the system is not generating
humidity. It is configured as a normally-open valve, meaning that it
vents whenever it is de-energized (whenever there is no power
applied).
When the humidity generator is generating humidity, SOL 2 is
energized to allow the saturator to pressurize normally. When the
humidity generator is generating, the ECB’s DC CONTROL – RLY 13
sources 24 VDC to energize the vent solenoid causing it to stop
venting. An LED on RLY 13 also indicates the relay status. When the
LED is on, the solenoid coil is energized and the valve is not venting.
Note that during normal operation of the humidity generator, the coil
is energized and the valve will be hot to the touch.
6.2.9 DRYER BLEED, SOL 10 (OPTIONAL)
The air dryer operates by continuously bleeding a small flow of air past a water permeable membrane. The air
dryer may optionally be equipped with a dryer bleed valve. When the system is running, the bleed valve energizes
to activate the drying operation. While drying, a few liter/min of air bleeds from the dryer. When the system is
shut down and dry air is no longer required, the valve deactivates, preventing air from bleeding unnecessarily. If no
bleed valve is installed, the dryer bleeds continuously regardless of system run status or dry air demand.
6.3 FLUID SYSTEM
There are several separate and distinct fluid systems in the humidity generator. The saturator fluid circulation
system, utilizing a 30-50% mixture of propylene glycol and water, is used to control the temperature of the
saturator. The fluid in this system, while thermally coupled to the saturator, never comes in direct contact with the
gas stream.
The chamber fluid circulation system, utilizing a 30-50% mixture of propylene glycol and water, is used to control
the temperature of the chamber and window. The saturator and chamber fluid circulation systems, while
independently controlled, utilize a common fluid expansion tank and therefore share a common fluid source.
A separate fluid system, utilizing distilled water only, is used to humidify the incoming gas, and is the main source
of humidity in the system’s outgoing gas stream. Humidification is accomplished by maintaining a set water level
within the presaturator. This liquid level control system requires sufficient distilled water supply level be
maintained by the operator. A distilled water reservoir tank is located within the lower cabinet.
6.3.1 DISTILLED WATER SUPPLY
Distilled water is required and must be maintained at a sufficient level in the distilled water reservoir tank in the
lower cabinet. This tank is connected via a suction tube to the presaturator via the preset fill pump.
The operator is responsible for maintaining distilled water in this tank, filling it when required.
SOL 2
Figure 6.15