Controlled Crown Roll
Controlled Crown Roll
Symbol Description
AF1 Air Filter
The element will remove particles of contamination from the air prior
to being directed to the AR1 and IP1 air regulators. The filter should
be changed on a regularly scheduled basis.
AR1 Air Regulator
This regulator is used to reduce the air pressure to the IP1 electrically
controlled regulator.
FCV1 Air Operated Flow Control
This valve is used to determine the nip pressure in the crown roll.
When there is no air pressure at the pilot port the valve will be fully
open. The nip pressure pump volume will flow through the valve and
back to tank. Once the pumps have started, a signal will be applied to
the IP1 valve coil directing air pressure to the pilot port of the valve.
The higher the air pressure, the more the valve will close. This will
permit a high pressure to be built up in the roll. When the air pressure
is lowered the hydraulic pressure in the roll will drop and more oil will
be ported back to the tank through this valve.
FCV1 Valve
Troubleshooting Papermill Hydraulics
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Controlled Crown Roll
F1 Filter
The online scavenger pump volume is ported through the element
prior to being directed through the heat exchanger and to the tank. If
the element becomes contaminated, red will show in the visual
indicator on top of the filter. To change the filter, the NC bypass
should be opened and the NO valves at the inlet and out ports should
be closed. Although not shown on the schematic, the filter may
contain an internal bypass check valve. The filter should be changed
regularly to keep contaminants in the roll from entering the reservoir.
Once the pressure at the filter inlet reaches 50 PSI, the pump volume
will flow through the PCV3 relief valve.
F1 Filter
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Controlled Crown Roll
F2 Filter
The lubrication flow is first ported through this filter before being
directed to the roll. Although not shown on the schematic the filter
may contain an internal bypass check valve. If this is the case then
the oil will bypass the element when it becomes contaminated. Red
will be shown in the visual indicator on top of the filter housing when
the element is contaminated. If no check valve is contained in the
filter then the oil will flow through the PCV4 relief valve once the
setting of the spring is reached. The element should be checked and
changed regularly.
FS1 Flow Meter and Switch
The meter will provide a visual indication of the lube pump flow to the
roll. The lube pump is rated for 12.8 GPM. If the flow drops below the
setting of the switch an electrical signal will be sent. A warning or
shutdown condition will occur, depending on the electrical
programming.
FS1 Flow Switch
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Controlled Crown Roll
GA1-GA5 Gauges
The gauges indicate the hydraulic pressure in the specific line.
These pressures should be recorded for future troubleshooting
purposes.
GA1 Gauge
HE1 Heat Exchanger
The oil that is ported out of the online Scavenger pump is directed
through this water cooler prior to returning back to the tank. The water
flow is ported through the tubes in the opposite direction. The heat in
the oil is transferred from the oil to the water. To achieve the most
efficient heat transfer the water flow should be 25% of the oil flow.
The water flow is controlled by the WM1 water modulating valve. The
valve will open a small amount when the oil temperature in the
lubrication line reaches the setting of the valve. The higher the oil
temperature, the more the modulating valve will open and a higher
flow of oil will be directed through the tubes. There should be a
noticeable temperature difference in the water lines when water is
flowing through the internal tubes.
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Controlled Crown Roll
For cleaning the cooler, circulate hot wash oil or light distillate
through the tube side or shell side. This will usually effectively
remove sludge or similar soft deposits. Soft salt deposits may be
washed out by circulating hot fresh water. Some cleaning
compounds such as “Oakite” or “Dowell” may be effective in
removing more stubborn deposits.
HE1 Heat Exchanger
HP1 and HP2 Nip Pressure Pumps
These pumps supply a constant volume, 4.78 GPM, to the roll for
pressurizing the nip. The pump is located on the back side of the lube
pump. Only one pump runs at a time. The other pump is used as a
back up or spare pump. The temperature of the pump housing and
suction line can be checked to determine pump wear. If possible
make this test when the pump is relatively new to establish a
reference. The more the pump bypasses internally, the higher the
temperature of the housing. The oil not used to maintain pressure on
the nip piston in the roll will return to the tank through the FCV1 valve.
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Controlled Crown Roll
IP1 Air Regulator
This valve is used to control the pilot pressure to the FCV1 valve. The
valve operates off of a 4-20 milliamp signal. The air pressure ported
out of the valve is directly proportional to the applied milliamp signal.
The pressure in the crown roll is fedback to the PLC by the PT1
pressure transducer. If the pressure is above or below the desired
setpoint pressure the electrical signal will be increased or decreased
to this valve. When a higher signal is applied, the air pressure is
increased to the FCV1 pilot port. This permits the FCV1 valve to shift
more closed restricting the flow back to the tank. This causes the
pressure to increase in the roll.
LP1 and LP2 Lubrication Pumps
These fixed displacement, 12.8 GPM pumps deliver a constant
volume of oil at all times. Only one pump runs at a time therefore the
other pump is used as a back up or spare. The oil is ported through
the F2 filter and FS1 flow switch then into the roll for lubrication
purposes. The volume that the pump is delivering will be indicated on
the FS1 flow switch. The PCV2 relief valve limits the maximum
pressure downstream of the pump. During normal operation no oil
should flow through this relief valve.
NO Manual Valves
All valves labeled on the schematic with an “NO” designation are
normally open during the operation of the machine.
OFDV Oil Fill Directional Valve
When the oil level in the reservoir drops to a certain level, this valve’s
solenoid is energized. Oil can then flow from the oil storage tank to fill
the tank. When the desired level is reached, the solenoid is
de-energized. The valve is a normally closed, two position, two way,
single solenoid, spring return, directional valve.
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Troubleshooting Papermill Hydraulics
Controlled Crown Roll
PCV1 Relief Valve
This valve will limit the maximum pressure immediately downstream
of the operating nip pressure pump. The recommended setting of the
valve is 225 PSI. During normal operation, this relief valve should not
open therefore the tank line should be cool. If all the pump volume
can not flow through the FCV1 valve, pressure will build until the
spring setting is reached. The valve will open and dump the excess
oil not used to maintain the pressure in the roll back to the tank. If this
valve were to fail open then a lower nip pressure could result.
PCV1
PCV2 Relief Valve
This valve is used to limit the maximum pressure in the lubrication
circuit. During normal operation this valve should not open. If a
blockage occurs and the lube system requires less than the
lubrication pump volume, 12 GPM, the valve will open directing the
excess oil back to the tank. This valve should not be set above the
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Controlled Crown Roll
maximum pressure rating of the F2 filter. The recommended setting
is 100 PSI. If this valve were to fail in the open position, then the flow
switch would indicate a low lubrication flow condition. The valve can
be taken apart and inspected for contamination or broken springs if
this were to occur.
PCV3 Relief Valve
This valve is used to limit the maximum pressure at the outlet port of
the online scavenger pump. Under normal conditions this relief valve
should remain closed at all times. Therefore the tank line of the valve
should be cool. If the filter or heat exchanger were to plug up with
contamination and the pressure builds to 50 PSI, the valve will shift
open. The Scavenger pump volume would then flow through the
valve and back to the tank. The recommended setting of the valve is
50 PSI. To set the valve, close the NO valve at the inlet of the F1 filter.
Adjust the relief valve until 50 PSI is read on the gauge.
PCV3 Relief Valve
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Troubleshooting Papermill Hydraulics
Controlled Crown Roll
PCV4 Filter Bypass Valve
This valve is used to allow the oil to bypass the filter when the element
is contaminated. The filter has a visual, color coded indicator on the
housing. When the indicator is green, the element is clean. When red
is shown, the filter is contaminated and the oil will bypass through the
relief valve providing there is no bypass check valve located inside
the filter housing.
PS1 Pressure Switch
This switch is used to electrically indicate when the pressure at the
HP1 pump outlet drops below 15 PSI. The HP2 pump will then be
started.
PS1 & PS2 Presure Switches
PS2 Pressure Switch
This switch is used to electrically indicate when the pressure at the
HP2 pump outlet drops below 15 PSI. The HP1 pump will then be
started.
Troubleshooting Papermill Hydraulics
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Controlled Crown Roll
PT1 Pressure Transducer
This transducer converts the pressure downstream of the online nip
pressure pump into a proportional milliamp signal. The pressure will
be sent to the machine controller. The signal to the IP1 transducer will
then be maintained, increased or decreased as necessary to
generate the desired nip force in the roll.
PT1
SP1 and SP2 Scavenger Pumps
These fixed displacement, 19.4 GPM pumps are used to remove the
oil from the roll. The system is designed to run only one pump at a
time. The online pump will create a vacuum to pull the oil out of the
roll. The oil is then directed for through the F1 filter and HE1 heat
exchanger before returning to the tank.
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Controlled Crown Roll
SP1 & SP2 Pumps
VT Volume Tank
This tank stores pressurized air so that when the signal to the IP1
regulator is changed, the response time to raise the nip pressure will
be quicker.
WM1 Water Modulating Valve
The oil temperature in the lubrication line is sensed to the valve
through a capillary tube. Once the initial temperature setting of the
spring is reached, the valve will shift open a small amount. This ports
a low flow of water through the cooler. As the oil temperature rises,
the valve will shift more to the open position. This permits a higher
flow of water through the cooler.
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Controlled Crown Roll
WM1 Valve
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Controlled Crown Roll
Lube & Nip Pressure Pumps
Lube Filter & Relief Valves
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Controlled Crown Roll
Gauges at Roll
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