R-100
BALANCED PISTON FIRST STAGE REGULATOR
DESCRIPTION AND OPERATION
The piston will remain in the CLOSED position until the intermediate pressure in
the LP hose is lowered by the actuation of the demand lever in the second stage
regulator during inhalation. This lowering reduces the pneumatic force acting
against the front of the HP piston head which permits the combined force of the
HP spring and the ambient water pressure to move the HP piston to the OPEN
position allowing high pressure air to flow into the swivel chamber again.
The first stage piston is pneumatically “balanced” meaning that the high pressure
air surrounding it exerts no opening or closing force against the piston itself. The
advantage of a “balanced” piston is that the first stage regulator maintains a
stable intermediate pressures range of 128 to 150 psi over ambient pressure,
despite a continually decreasing supply pressure from the SCUBA cylinder. This
stabilization of intermediate air pressure in the first stage assures optimal second
stage performance as the air supply in the SCUBA cylinder is depleted.
The balanced piston first stage of the R-100 Regulator functions to deliver the
intermediate pressure at 135 to 145 psi above the depth related ambient
pressure. This depth compensation is achieved by allowing ambient water to
enter the main body and flood the HP spring area and act upon the back side of
the HP piston. As the diver descends the ambient water pressure becomes the
reference point from which the HP piston controls the intermediate pressure from
135 to 145 psi above ambient pressure. The balanced piston first stage
maintains a constant differential between surrounding ambient water pressure
and intermediate air pressure. This helps to assure that the effort to actuate the
second stage will remain relatively constant with changing depth.
Revised v1.0-2000
6
FIG. 2-b
FIG. 2-a
CLOSED POSITION
OPEN POSITION
