Cla-Val 790-01 - Manual (Page 4)

Principle of Operation
Model 100-42 Valve
in Closed Position
Upstream pressure is introduced to the
control chamber (the chamber formed
behind the liner) of the Cla-Val Model
100-42 Roll Seal valve through the con-
trol 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
acting 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.
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
ROLL SEAL
700 SERIES
MODEL
• Compact Design, Proven Reliable
• Light Weight Materials
• High Pressure Rating Availability
• Easy Installation and Maintenance
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 constructed with internal ribs and
slots forming a grillwork which surrounds the liner to provide 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 operate the Model 100-42 valve consists
of a restriction and a suitable pilot connected to the valve.