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English
The current Service Manual can be found at www.medivance.com/manuals
Chapter 3 – Theory of Operation
Main Hydraulic Circuits
Circulation Circuit
– circulates temperature-controlled
water from the Circulation Tank through the ArcticGel™
Pads and returns to the inlet port of the Circulation Pump.
The speed of the Circulation Pump varies to maintain -7.0
PSI (0.5 bar) at the Pressure Sensor. Since water in the
ArcticGel™ Pads flows under negative pressure, a break in
the circuit, such as a pad being punctured or disconnected,
will result in air leaking into the system instead of water
leaking out. Air in the system is removed in the Circulation
Tank and exits through the tank vent. When warmer water
is required, the heaters located in the Circulation Tank
are energized. The heater power is dependent upon the
flow rate through the circulation tank and the difference
between the water temperature and the commanded
water temperature. The heater has four elements that are
cycled on sequentially to minimize power fluctuations in
the mains supply.
Chiller Circuit
– maintains the water in the Chiller Tank
at approximately 4°C. Water is gravity-fed into the
centrifugal Chiller Pump and is then pumped through the
chiller’s evaporator and returned to the Chiller Tank. The
refrigerant system’s cooling capacity is controlled by a
refrigerant valve. When the Chiller Circuit approaches 4°C,
the cycling of the valve can be heard.
Mixing Circuit
– when cold water is required to cool the
Circulation Circuit, the Mixing Pump pulls water from the
Circulation Tank and meters it into the Chiller Tank. Cold
water overflows from the Chiller Tank into the Circulation
Tank. The speed of the mixing pump is dependent
upon the flow rate through the circulation tank and
the difference between the water temperature and the
commanded water temperature.
Ancillary Hydraulic Circuits
Filling
– When filling, the Fill Valve is opened, and water
is drawn up through the valve by the Circulation Pump.
Water returns through the Circulation Tank to the Supply
Tank. Negative Pressure must be generated at the inlet
of the Inlet/Outlet Manifold for filling to occur, therefore
the Fluid Delivery Line must be attached. ArcticGel™ Pads
should not be attached to the Fluid Delivery Line during
filling.
Preconditioning
– The system can be programmed to
precondition water prior to initiating therapy. In this mode,
the Bypass Valve opens and allows temperature-controlled
water to circulate internally to bring the Circulation Tank
and Supply Tank water to a pre-programmed temperature.
Empty Pads
– To empty water from the ArcticGel™ Pads,
the Vent Valve is opened, which enables air to enter the
pads. Water is pulled from the pads by the Circulation
Pump and returned through the Circulation Tank to the
Supply Tank.
Fig 2-1 Hydraulic Schematic
MIXING
PUMP
CHILLER
PUMP
CHILLER
TANK
CIRCULATION TANK
CIRCU-
LATION
PUMP
EVAPORATOR
CHILLER
AIR FLOW
AIR FLOW
FLOW METER
SUPPLY TANK
CHILLER
CIRCUIT
CIRCULATING CIRCUIT
INLET/OUTLET
MANIFOLD
ATMOSPHERE
HEATER T2
T1
T4
DRAIN PORTS
VENT
FILL LINE
ARCTICGEL
PAD
BYPASS LINE
FV
T3
P1
BV
VV
KEY
VV Vent Valve
BV Bypass Valve
FV Fill Valve
P1 Pressure Sensor
T1 Outlet Monitor Temperature
T2 Outlet Control Temperature
T3 Inlet Temperature
T4 Chiller Temperature
VALVE
FLUID
DELIVEY
LINE
VALVE
FLUID
DELIVERY
LINE
