JFD KI40018AA, Руководство по эксплуатации и обслуживанию

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3
KI-OM-6768 R0 Chapter 1
1.3 T
HEORY
O
F
O
PERATION
1.3.1 Basic Control
The temperature control system of the WHE-03 has been designed to be simple and effective. The
unit heats water in the heater tank using five banks of heater elements. These heater banks are
controlled with five switches, mounted on the electrical enclosure. The banks of heaters are
configured to deliver a variety of heating capacities depending on the combination of banks
selected. When all five heater circuits are on, the total rated heater output is approximately 180 kW.
The appropriate heater circuits must be selected manually according to the relative temperature rise
required. A schedule is attached to the front of the control panel door indicating the heater banks to
be used for the required temperature rise.
Example: Temperature rise through the WHE and heater bank selection
The above example shows that if a bottom temperature of 43ºC is required with a temperature drop
through the hose to the diver of 11ºC and an inlet water temperature of 5ºC. The temperature
required at the outlet of the WHE would be 54ºC. The Temperature rise through the unit would be
49ºC. The heater selection schedule shown in Table 3.1, indicates that heater banks 1 through to 5
should be used as this would provide a temperature rise of 47-50ºC through the unit.
Once the correct configuration of heater banks has been selected, the temperature controller
regulates the temperature of the outlet by adjusting the flow rate of water passing through the heater
tank. This is achieved by controlling the electric actuator on the bypass valve. The valve is
connected in such a way that it will dump water overboard to increase the flow rate through the
heater tank. A higher flow rate through the heater reduces effective temperature rise and maintains
the desired set point temperature. The temperature controller monitors temperature at the fluid
outlet manifold using a PT100 temperature sensor and adjusts the temperature control valve
position to achieve the set point temperature.
If applicable (when remote, control panel installed) switching the temperature controller input from
local to remote input allows fine control of the outlet temperature by adjustment of the potentiometer
on the remote control panel. Manipulation of the potentiometer will change the set point of the
temperature controller. Refer to the temperature controller manual in Appendix F for instructions
regarding switching between local and remote temperature set-point adjustment.
T
d
- Required outlet water temperature, at diver = 43ºC
T
∆ h
- Temperature drop (Hose from deck to diver) = 11ºC
T
i
- WHE Inlet water temperature is = 5ºC
T
o
- WHE desired outlet temperature = T
d
+T
∆ h
= (43 + 11)ºC
= 54ºC
∆ T - Temperature rise through the WHE = T
o
+T
i
= (54 – 5) ºC
= 49ºC
(Use heater banks 1, 2, 3, 4 and 5)