Leslie Controls CONTROL VALVES SINGLE PORTED DOS - Manual (Page 3)

3
INSTALLATION
Valve Position
(see Fig. 1)
Install control valve in the highest horizontal line
of piping, in an accessible location and with
arrow on side of valve body in direction of fluid
flow. Control valve may be placed in any
position, but upright is preferable for ease of
maintenance.
Figure 1 - Typical Installation
Problem Preventing Procedures
1.
Provide removal space above, below
and around control valve for easy
removal of parts during maintenance.
See proper drawing for dimensions.
2.
Blow or flush out pipelines thoroughly
before installing control valve.
3.
Protect control valve and the following
equipment with a self-cleaning strainer.
4.
Install stop valves and gauges in inlet
and outlet lines to provide means for
checking adjustment and operation of
equipment.
5.
Provide proper inlet and outlet drainage
in steam service to prevent water
hammer
or possible erosion of
equipment.
6.
Adhere to good piping practice. Install
a bypass around the control valve.
Connect operating medium tubing from control
pilot instrument or loading device to diaphragm
chamber connection of control valve or to valve
positioner, if one is in use.
Important: If control valve is fitted with a
Thermo-Isolating bonnet, do not lag or insulate
bonnet or paint it other than dull black, otherwise
its heat emitting efficiency will be impaired and
packing will be submitted to excessive
temperature.
RECOMMENDED PIPING FOR CONTROL
OF COMPRESSIBLE FLUIDS AT VALUES
OF 25% OR LESS OF INLET PRESSURE.
1.
Expand outlet pipe to twice control
valve inlet pipe size. Use tapered
expander.
2.
Connect control pipe for control pilot
ahead of outlet stop valve and at least 2’
to 3’ downstream from end of expander.
3.
Make control pipe connection at least
18” to 24’’ from outlet stop valve, any
elbow or other flow direction out
changing fitting. (see Fig. 2)
Figure 2 - Typical Control Valve Station for
Control of Compressible Fluids at 25% or
Less of Inlet Pressure
NOTE: Where sensing impulse is taken 2’ to 3’
downstream from control valve (expander),
dimension “A” minimum of 6’ to 10’ will
provide lowest noise and velocity factors,
accurate pressure sensing and reasonable bypass
length.
OPERATION
1.
Close inlet and outlet stop valves.
2.
Check that control valve responds
properly through rated travel in relation
to changes in operating pressure on the
CAUTION!
The piping system must be adequately
designed and supported to prevent
extraordinary loads to the pressure