Technical data
ACT VS 3000 - 6000
EN - 21
11 Technical description
11.1 Control panel
The control panel explained below is the only dryer user interface.
PQ
S0
0
9
8
1
Main switch
2
Electronic instrument DMC50
11.2 Operation
Operating principle
- The dryer models described in this manual operate all on the same principle. The hot moisture
laden air enters an air to air heat exchanger. The air then goes through the evaporator, also known as the air to
refrigerant heat exchanger. The temperature of the air is reduced to approximately 2°C, causing water vapor to
condense to liquid. The liquid is continuously coalesced and collected in the separator for removal by the condensate
drain. The cool moisture free air then passes back through the air to air heat exchanger to be reheated to within 8
degrees lower than the incoming air to the dryer.
Refrigerant circuit
- Refrigerant gas is exhausted by the compressor and exits at high pressure towards a condenser
where heat is removed causing the refrigerant to condense to a high-pressure liquid state. The liquid is forced through
an electronic expansion valve (EEV) where the resulting pressure drop allows the refrigerant to boil off at a
predetermined temperature. Low-pressure liquid refrigerant enters the heat exchanger where heat from the incoming
air is transferred causing the refrigerant to boil; the resulting phase change produces a low pressure and low
temperature gas. Then the low-pressure gas goes back to the compressor, where it is re-compressed and begins the
cycle again.
Operation in eco mode (Variable Speed)
– The DMC50 electronic controller constantly monitors the evaporating
pressure (BLP), the condensing pressure (BHP) and the temperature of the DewPoint (BT1).
At each compressor start-up VS (Variable Speed) c
ompressor’s speed is forced to a fixed speed (approx. 40-50% of its
maximum speed) for approx. 3 minutes to allow a proper oil circulation in the refrigerant circuit. During this period, if the
evaporating pressure (BLP) falls too low, DMC50 will activate a solenoid valve EVB that will increase the evaporating
pressure above the freezing point.
Expired the first 3 minutes, DMC50
will adjust VS compressor’s speed in order to keep the evaporating pressure almost
constant, allowing a constant DewPoint even with dryer thermal load variation.
Having an higher load to the dryer, the capacity of the VS compressor to its maximum speed is insufficient, the
evaporation pressure tends to increase beyond the set-point, so the FIX speed (on-off) compressor is activated
increasing the system cooling capacity. At this point VS compressor speed is automatically adjusted to maintain the
evaporation pressure to the set-point.
In 5000-6000 VS an additional FIX speed (on-off) compressor is installed to increase the system cooling capacity.
When the load to the dryer decreases, with VS and FIX compressors turned on, the speed of the VS compressor is
decreased up to its minimum value; if the cooling capacity is still too high, the FIX compressor is switched off and VS
compressor speed is automatically adjusted to maintain the evaporation pressure to the set-point. In very low load
conditions (or no load), VS compressor will run at its lowest allowable speed.
Even if that speed is larger than load demand, the evaporating pressure will decrease from its setting point and when
the temperature of the DewPoint tends to fall close to the freezing point, the DMC50 controls the switching off of the VS
compressor.
The VS compressor will be started again when the DewPoint temperature and evaporating pressure rises above a
target value.
The VS compressor is always the first to start and is always the last to stop.
The check valve CHV in combination with the Electronic Expansion Valve (EEV) help to extend the off time of the
compressor and avoid the immediate balancing of high and low pressures of the refrigerant circuit.
The solenoid valve EVB is activated before the compressor start as long as refrigerant pressures (low and high) get
balanced.
Fan(s) speed will be controlled by the DMC50 in order to keep the condensing pressure measured by BHP almost
constant (air cooled).
With these dryers, the energy consumption will be adjusted closely proportional to the thermal load applied to the dryer
itself, allowing considerable energy savings in the majority of applications.
Содержание ACT VC 3000 - 6000
Страница 52: ...Attachments 52 EN ACT VS 3000 6000 ...
Страница 53: ...Attachments ACT VS 3000 6000 EN 53 ...