Installation
and adjustment
In
pursuit of optimal operation, during installation the control
lever for valve location should be installed on top (most ideal)
or side of the conveying line. The sealing of valve is realized
via the superimposition between valve disk and valve seat. Therefore,
the valve support should be independent of the conveying line
and not withstand force from pipeline devices. In addition, measures
should be taken to prevent the expansion of pipelines for heating
from applying force on the valve.
The installation of changeover valve should be able to prevent
air pressure in valve closing branch from
acting
on the sealing surface of valve disk, as shown in the figure.
Operation and application:
The
transposition of valve disk should be carried out on condition
that the system stops operation (no pressure), however, the valve
should not be manipulated as the system is conveying materials,
because:
（1）The valve disk is under pipeline pressure, the wear will accelerate
if the valve disk is moved under load;
（2）Movement of the valve disk under load will produce a load higher
than normal torque causing failure of the valve disk to operate
normally;
（3）If transposition of the valve disk is performed during conveyance
of materials by the system, the accumulation of materials will
be created due to loss of pressure in some pipeline of the valve.
As a result, abnormalities such as pipe jam, pressure fluctuation
and overload of air compressor, etc. will be caused when this
pipeline is enabled once more next time. Before transposition
of the valve disk the conveying pipe should be cleared up and
blown off. When transposition is made by manipulating the valve
after stop of the system, it is quite favorable to rotate the
control lever for valve location for several times first, and
then to transpose the valve disk to required position, in such
way the valve seat is cleaned and the life of valve is extended
as well.
During outage of conveying system, rotating the control lever
for valve location is in favor of removing accumulating contaminants
such as dust and condensed water, etc. so as to prolong the life
of valve seat. 。
Automatic opening and closing of the pneumatic changeover valve
are accomplished by valve used pneumatic device (cylinder). After
power source and air source are connected, the cylinder drives
transposition of valve core to make the valve stop at proper location.
