JFD KI40018AA, Operation And Maintenance Manual, Page: 12 / 110

4
Chapter 1
KI-OM-6768 R0
1.3.2 Fluid System
The WHE-03 may function with either salt water or fresh water as the heating medium. The unit is
provided with two inlets for fluid, one for fresh water and one for seawater. The fresh water line is
typically used for flushing the system after use, and is fitted with a check valve to prevent salt water
contamination of the fresh water supply. The unit uses small immersion heater elements mounted in
the flange plates at either end of the stainless steel heater tank to heat the fluid. The flow rate of the
fluid through the heating tank is governed by the action of the bypass valve.
The flow rate of fluid from the heater tank to the divers is determined by the motor speed and the
ratio of the pulley set used to couple the motor to the pump. The pump is a positive displacement
pump and is supplied with a pulley arrangement to provide a flow rate of 45 litres/min.
The fluid to be heated enters the unit at the chosen inlet and flows through a manifold and a quarter-
turn hand valve. The manifold is equipped with analogue temperature and pressure gauges to
provide operator feedback on the fluid supply. The fluid is then piped to the fresh water inlet tee and
distributed to two separate inlet filters. The filters may be isolated using hand valves on the inlet and
outlet of each filter. These filters clean input water of particulate matter down to 50µm in order to
protect the piston pump and umbilical coupling from being damaged and prevent clogging of the
heating water tubes in the diver suits. The inlet filters are each fitted with pressure gauges in order
to monitor pressure drop across the filter and indicate the condition of the filter cartridge. A pressure
regulating valve fitted after each filter outlet ensures that fluid is supplied from filters to heater tank at
a consistent and safe pressure, (Factory setting is 2 bar).
The fluid flows through the heater tank which houses immersion heater elements where fluid is
heated. The heater tank is fitted with a pressure relief valve (PRV), set to 2.5 bar. A float switch
housed in the level control tank mounted on top of the heater tank is used to ensure the heater
elements and pump are not run without sufficient supply. If the level in the tank drops the level
switch shuts down the system. From the level control tank, the fluid is distributed to the temperature
control valve, manual temperature control valve and pump. The manual control valve controls the
process in the same way as automatic control valve and is provided to control the outlet temperature
if automatic control is inactive. The pump supply is directly coupled to the level control tank.
I
MPORTANT
The calculated required temperature rise may be indicated on the heater bank selection
table as a maximum for one configuration and a minimum on the subsequent selection of
heater banks. In this case practical application will dictate which configuration should be
used. The higher capacity configuration is usually used to allow for better control.
If the bypass dump valve remains fully open during normal operation, indicating heating
over-capacity then the lower kW heater configuration should be used to improve control
and unit performance.
If the bypass valve remains fully closed during normal operation, indicating heating
under-capacity or a possible heater bank fault then a higher kW configuration should be
used to improve control.
I
MPORTANT
Fluid supply to the unit by the vessel must be maintained above 45 litres/min at 3 bar for
correct operation.