Gas first enters inlet pipe _A_ (Fig. 3) passing along _A1_ into
covered valve chamber _B_ up through orifice _O_. It then passes down
through two of the valve ports at the same time, ports _C_ and _D1_
(Fig. 2). Before _C1_ (Fig. 3) has gotten to its extreme opening, the
valve on the opposite side has moved to allow gas to pass down port
_D_. On every quarter turn of tangent _P_, one port is opening to
receive gas which passes down through the valve ports into the chambers
below (see arrows on Fig. 2), which shows the gas passing into chamber
_F_. The pressure being greater on the outside of the diaphragm, forces
the diaphragm inward and expels the gas from the inside of _D2_ through
_D_ and passes over the cross-bar into the fork channel (see Fig.
1). On the other side gas is passing down through port _D1_ (Fig. 2)
entering diaphragm _D3_, the pressure being greater on the inside of
_D3_ therefore forces the diaphragm outward and expels the gas from
the outside of diaphragm _D3_; out through port _C1_ into fork channel
same as shown in (Fig. 1). All exhaust gas from the chambers below
is checked from entering the chamber _B_ by the slide valve _G_ and
_G1_ (Fig. 2). Instead of passing into chamber _B_ it passes over the
cross-bars between _D1E1_ and _C1E1_ into the fork channels, then to
outlet pipe _N_ (Fig. 3) to house pipe.