DISCUSSION
We have conduct experiment on three type of valves, that is
linear valve, equal valve and quick valve. The experiment is
conducted to use the valve correctly. In this experiment, we will
identify the function of each component in the instrument and how
to operate the operation of control valve. In addition, in this
experiment we will know the classification of the valve. The
control valve characteristics refers to the relationship between
the volumetric flowrate F (Y-axis) through the valve and the valve
travel or opening position m (X axis), as the valve is opened from
its closed position to various degree of opening. (Note that the
symbol m or Z is used here to represent the valve travel or opening
position, in %). Trim design of the valve affects how the control
valve capacity changes as the valve moves through its complete
travel. Because of the variation in trim design, many valves are
not linear in nature. Valve trims are instead designed, or
characterized, in order to meet the large variety of control
application needs. Many control loops have inherent non
linearity's, which may be possible to compensate selecting
thecontrol valve trim. Based on the graph, we could see that the
data at both small pumps and big pumps are almost the same when has
been converted into a graph. When at linear valve the flow capacity
increases linearly. When at equal valve the flow capacity increases
exponentially with valve trim travel. Equal increments of valve
travel produce equal percentage changes. When at quick valve we can
see that it provides large changes in flow for very small changes
in lift. Valves of any size or inherent flow characteristic which
are subjected to the same volumetric flowrate and differential
pressure will have exactly the same orifice pass area. However,
different valve characteristics will give different 'valve
openings' for the same pass area. In water systems, the pump
characteristic curve means that as flow is reduced, the upstream
valve pressure is increased. The characteristic of the control
valve chosen for an application should result in a direct
relationship between valve opening and flow, over as much of the
travel of the valve as possible. This section will consider the
various options of valve characteristics for controlling water and
steam systems. In general, linear valves are used for water systems
whilst steam systems tend to operate better with equal percentage
valves.
DISCUSSION
We have conduct experiment on three type of valves, that
is linear valve, equal valve and
quick valve. The experiment is conducted to use the valve
correctly. In this experiment, we
will identify the function of each component in the instrument
and how to operate the
operation of control valve. In addition, in
this experiment we will know the classification of
the valve.
The control valve characteristics refers to the relationship
between the volumetric
flowrate
F (Y
-
axis) through the valve and
the valve travel or opening position m (X
axis), as
the valve is ope
ned from its closed position to various degree of opening. (Note
that the
symbol m or Z is used here to represent the valve travel or
opening position, in %).
Trim
design of the valve affects how the control valve capacity
changes as the valve moves
throug
h its complete travel. Because of the variation in trim design,
many valves are not
linear in nature. Valve trims are instead designed, or
characterized, in order to meet the large
variety of control application needs. Many control loops have
inherent non
linearity's, which
may be possible to compensate selecting the
control valve trim
.
Based on the graph, we could
see that the data at both small pumps and big pumps are almost
the same when has been
converted into a graph. W
hen at linear valve the flow capa
city increases linearly
. When at
equal valve the
flow capacity increases exponentially with valve trim travel.
Equal
increments of valve travel produce equal percentage changes
. When at quick valve we can
see that it
provides large changes in flow for very
small changes in lift
.
Valves of any size or
inherent flow characteristic which are subjected to the same
volumetric flowrate and
differential pressure will have exactly the same orifice pass
area. However, different valve
characteristics will give differ
ent 'valve openings' for the same pass area.
In water systems,
the pump characteristic curve means that as flow is reduced, the
upstream valve pressure is
i
ncreased.
The characteristic of the control valve chosen for an
application should result in a
direct relationship between valve opening and flow, over as much
of the travel of the valve as
possible.
This section will consider the various options of valve
characteristics for controlling
water and steam systems. In general, linear valves are used
for
water systems whilst steam
systems tend to operate better with equal percentage valves.
DISCUSSION
We have conduct experiment on three type of valves, that is
linear valve, equal valve and
quick valve. The experiment is conducted to use the valve
correctly. In this experiment, we
will identify the function of each component in the instrument
and how to operate the
operation of control valve. In addition, in this experiment we
will know the classification of
the valve. The control valve characteristics refers to the
relationship between the volumetric
flowrate F (Y-axis) through the valve and the valve travel or
opening position m (X axis), as
the valve is opened from its closed position to various degree
of opening. (Note that the
symbol m or Z is used here to represent the valve travel or
opening position, in %). Trim
design of the valve affects how the control valve capacity
changes as the valve moves
through its complete travel. Because of the variation in trim
design, many valves are not
linear in nature. Valve trims are instead designed, or
characterized, in order to meet the large
variety of control application needs. Many control loops have
inherent non linearity's, which
may be possible to compensate selecting the control valve trim.
Based on the graph, we could
see that the data at both small pumps and big pumps are almost
the same when has been
converted into a graph. When at linear valve the flow capacity
increases linearly. When at
equal valve the flow capacity increases exponentially with valve
trim travel. Equal
increments of valve travel produce equal percentage changes.
When at quick valve we can
see that it provides large changes in flow for very small
changes in lift. Valves of any size or
inherent flow characteristic which are subjected to the same
volumetric flowrate and
differential pressure will have exactly the same orifice pass
area. However, different valve
characteristics will give different 'valve openings' for the
same pass area. In water systems,
the pump characteristic curve means that as flow is reduced, the
upstream valve pressure is
increased. The characteristic of the control valve chosen for an
application should result in a
direct relationship between valve opening and flow, over as much
of the travel of the valve as
possible. This section will consider the various options of
valve characteristics for controlling
water and steam systems. In general, linear valves are used for
water systems whilst steam
systems tend to operate better with equal percentage valves.
