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SECTION 3 - SYSTEM COMPONENTS DESCRIPTION
The steam ring drain solenoid valve remains energized
(open) during the initial startup. The check valve in the
steam ring drain line prevents air from being drawn
into the turbine when the turbine steam ring drops be-
low atmospheric pressure during the initial evacuation
and while the turbine is slow rolling. When the inlet
steam valves open to begin slow roll and during the
ramp up to minimum speed, the steam ring will rise
above atmospheric pressure and any condensate will
be blown out of the turbine.
On older manually started chillers, the
steam ring drain is not automated. In this
case, the steam ring drain valve must be
manually opened at shutdown and closed
after the turbine is slow rolling at initial
start up.
On standard YST chillers with up-discharge turbine ex-
haust, an exhaust casing drain connection is supplied.
The turbine must be supplied with a means of draining
the casing during operation (while under vacuum). The
standard Factory supplied option is an automatic pres-
sure powered pump. Also available by special quota-
tion is a condensate drain tank (manual or automatic).
When either option is supplied, it is shipped loose for
installation at the job site.
On non-condensing turbines with side-discharge tur-
bine exhaust, there is no need for an exhaust casing
drain since condensate cannot collect in the turbine ex-
haust end.
On any application where the exhaust piping bends
upward after leaving the turbine, steam traps must be
provided to keep the exhaust line drained to prevent
water from building up in the exhaust pipe and turbine
casing.
Failure to keep the exhaust line drained
may result in a restriction in the exhaust
line, causing a loss of power and damage
to the turbine rotor.
Pressure Powered Condensate Drain Pump
A Factory supplied automatic pressure powered pump
is provided for draining condensate from the steam
turbine casing, during operation. The pressure power
pump is shipped loose and all piping and installation
is provided by others.
58
An automatic pressure powered pump is
supplied by Johnson Controls when the
Auto-Start option is ordered.
Liquid enters the pump body through the inlet check
valve causing the float to rise. As the chamber fills
the valve changeover linkage is engaged opening the
motive supply valve and closing the equalizing valve.
As motive pressure is above the total back pressure,
condensate is forced out through the outlet check valve
into the return system.
Motive pressure for automatic pressure
powered pumps cannot exceed a maxi-
mum of 200 PSIG (steam or air may be
used). Application with higher pressure
motive supply must use custom selected
condensate drain equipment suitable for
higher pressures.
As the liquid level falls within the pump, the float re-
engages the valve changeover linkage causing the mo-
tive supply valve to close and the equalizing valve to
open allowing condensate to re-enter through the inlet
check valve and the cycle is repeated. Refer to YORK
standard flow diagram for typical pressure pump pip-
ing installation.
All the piping associated with the installation of the
Automatic Pressure Powered Pump is field provided
and installed .
Condensate Drain Tank – Optional Supply by
Special Quotation
When ordered, a Factory supplied condensate drain
tank is provided for draining the condensate from the
exhaust end of the steam turbine during operation. The
tank is shipped loose and all piping and installation is
provided by others.
The tank is provided with a high level alarm switch
which is connected to the OptiView™ Control Center
to signal the operator that the tank must be manually
drained by closing and opening the appropriate valves
to isolate the tank from the turbine during the drain-
ing process and allow the condensate to drain into the
sewer. If the tank is automated, the tank is provided
with a self contained control panel, float switches, and
solenoid valves to control the draining isolation/drain-
ing process.
FORM 160.67-O2
ISSUE DATE: 10/9/2020
JOHNSON CONTROLS
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