Danfoss PCV-VFQ 21, Инструкция по эксплуатации

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Pilot controller AVP-F
(Flow Rate) Adjusting throttle
Throttling element DE
Valve unit PCV-VFQ 21
Throttling valve
Throttling valve
only by DN150-250
2 VI.JA.G2.02
© Danfoss 11/2006 DH-SMT/SI
Instructions Pilot-controlled PCVQ DN 100 - DN 250 (PN 16, PN 25)
1 Safety Notes To avoid injury of persons
and damages to the device,
it is absolutely necessary to
carefully read and observe
these Instructions.
Necessary assembly, start-up, and maintenance
work may be performed only by qualified and
authorized personnel.
Please comply with the instructions of the
system manufacturer or system operator.
2 Definition of
Application
The controller is used for flow rate limitation of
water for heating, district heating and cooling
systems.
The admissible medium temperatures depend
on the design and comprise 5 to 140 °C,
5 to 150 °C, 5 to 200 °C.
The technical data on the rating plates
determine the use.
3 Description
3.2 Mode of Operation
The control unit consists of the PCV-VFQ21
valve unit, installed in the main pipe and AVP-F
installed as pilot controllers in the bypass. In the
bypass line, a throttle element is installed in front
of the pilot controller.
The controller keeps the differential pressure
across the main valve flow restrictor on a
constant level and restricts the flow rate to the
adjusted setpoints.
The valve and the pilot valves are pressure-
balanced.
The setpoint for the flow rate limitation is
adjusted at the adjusting throttle of the valve
unit.
The valve unit in the main pipe is opening on
rising pressure. The pilot controller in the bypass
line is closing on rising pressure.
3.1 Construction
Flow Rate Limitation
If the flow rate reaches the adjusted setpoint, the
differential pressure increases at the adjusting
throttle. This differential pressure acts on the
actuator AVP-F via the impulse tubes and the
valve AVP-F closes. Consequently, the valve of
the valve unit is throttled, too, and the flow rate
is restricted.