Cla-Val 750B-4KG - Manual (Page 7)

INSTALLATION / OPERATION / MAINTENANCE
Model 100-42 Valve
in Closed Position
Upstream pressure is introduced to the
control chamber (the chamber formed
behind the liner) through the control
piping and restrictor. When the pilot is
closed, full inlet pressure is supplied to
the control chamber, thus balancing the
force developed by inlet pressure act-
ing on the upstream face on the liner.
Under these conditions, the liner
remains in the fully closed position.
Since the operating pressure in the
control chamber is greater than the out-
let pressure, an additional closing force
is developed across the liner, pressing
the liner against the surrounding slotted
grillwork area and seating surface.
Model 100-42 Valve
in Partially Open Position
As loading pressure is lowered slightly
below inlet pressure, the central portion
of the liner is forced to invert and come
to rest against the tip of the control
chamber cavity. Reducing the loading
pressure further (but still higher than
outlet pressure) causes the liner to
drape over the cone shaped portion of
the control chamber cavity. This action
causes the outer section of the liner to
roll off the seating surface and a portion
of the grillwork to partially open the
valve.
Model 100-42 Valve
in Fully Open Position
The valve is fully opened when loading
pressure is sufficiently reduced to allow
the liner to roll back completely and
expose the full slot area. Restoring
loading pressure reverses the liner
rolling action to return the liner to the
fully closed position.
DESCRIPTION
PRINCIPLE OF OPERATION
PILOT
CONTROL
VALVE
RESTRICTOR
SEATING AREA
CONTROL CHAMBER
INLET
Pilot
Control
Valve
RESTRICTOR
SEATING AREA
CONTROL CHAMBER
INLET
PILOT
CONTROL
VALVE
RESTRICTOR
SEATING AREA
INLET
CONTROL CHAMBER
100-42
The Cla-Val Model 100-42 Roll Seal valve
is a hydraulically operated valve used to
control liquid flow by means of a flexible
control element, the liner.
The basic valve consists of only two parts:
a one piece, investment cast body and an
elastomeric liner. The valve body is con-
structed with internal ribs and slots forming
a grillwork which surrounds the liner to pro-
vide support. A normally closed type valve
is formed by the installed liner which covers
the grillwork and seats against the raised
seating surface in the valve body.
Upstream pressure actuates the valve to
produce valve opening by rolling the liner off
the seating surface and the slotted grillwork.
The valve is actuated by upstream pressure
as the loading pressure (pressure supplied
to the control chamber) is varied by an
external pilot control system.
A typical pilot control system used to oper-
ate the Model 100-42 valve consists of a
restriction and a suitable pilot connected to
the valve.
700 Series Roll Seal
SERIES