The news scimitar. (Memphis, Tenn.) 1907-1926, 1920-04-03
Copyright, 1920, by the International
CyndfnafaN


The accompanying diagram shows a
typical form of vacuum tank-one OF
several designs in common use. Here
A is the suction or pumping compart-
ment, which communicates with the
gravity feed compartment by means
of the. passage C, the lower end of which
may be closed or opened to B by the
swinging plate or "flapper" valve, ID.
e is the gasoline connection from B
to the carburetor, f the gasoline con-
nection from A to the main tank, G
the suction connection from A to the
intake manifold of the engine and Fl
is tube through which air. can enter
A, when it is required and through
which air is always free to enter B,
to take the place of gasoline that goes
which ridAs upon the surface Of the
gasoline Id A, the movement OF which
is guided by the stem l., the lower end
of which fits loosely in passage c.
The upper end of the float stem is
pivoted to one end of the jointed lever
M, the other end of which is mounted
on stationary pivot at n. One end
of the link o is pivoted to M, nearly
at its middle point and its other end is
pivoted to another lever p at a point
the other end of p being held upon a
stationary pivot II in the head of the
tank. AS the float X falls in compart-
ment A. because of the lowering OF
the gasoline level therein, it swings
lever NJ gradually downward and
through the action of link o, also
swings lever so that its free end
Is moved downward.
When the float rises, under an in
crease of gasoline in A, these actions
are reversed and the effect of the float
motion is gradually to raise and lower
the free end r of lever P, as it rises
and falls. Another lever S is pivoted
at r and operates. two valves one OF
which w, closes the passage between
suction pipe G and compartment A,
when 1t Is moved upward and the other
of which X opens the connection
through air-vent II from the outside air
to tank A when it is moved upward
the valves actions being reversed when
Grated directly by the float, but by the
tension spring V, the action of which
as here shown with the float up is
to raise lever S. 40
When, however, the float rails 10 JUS
lower position, spring passes below
the fulcrum point T. through the lower
ing of r and its pull then acts to sud
denly snap lever s down. opening the
suction and closing the air vent valves:
Lever thus moves positively ana
quickly from one extreme positloR 10
the other In obedience to float position,
whenever spring V is moved past the
fulcrum point T.
In the position here shown gasoline
is flowing by its own weight from COM
partment A to compartment B. flapper
valve ID, opening under its pressure
suction valve w being closed and air
vent valve X being open, so that there
shall be atmospheric pressure in ana
thus no interference to the flow of gaso- |
line into B. AS gasoline thus escapes
from A, the float falls and r moves |
downward until spring V acts to throw
S into it's reverse position and 10 close
air valve Y and open suction valve w,
when there is Immediately a reduction
of pressure in A. due to the tendency
for air to be drawn from 1t into the
intake manifold through w and G.
the entrance of outside air being pre-
vented by the closing of X.
AS there is always air pressure on
the fuel in B and this is greater than
tho pressure now acting on the gaso-
line in A flapper valve D is torceu
closed, so that no liquid can return from
to A. There being a partial vacuum
thus acting in A and fun atmospheric
pressure acting in the main tank, gaso-
line is forced through the delivery tube
z into A, which, Of course, causes the
float to rise. spring V to pass the full;
crum center, valve w to close ana
valve Y to open. when pumping ceases,
the initial conditions are restored, nap |
rer D opens and compartment b is
replenished .,..-..,-. -
These actions repeat themselves IN
definitely, while the engine is running,
some gasoline always being present IN
both 4 and b. and the fuel level in A 4
alternating in height between an uppeS !
limit, which brings the. float hign
enough to raise r sufficiently so that
the spring snaps S into its upper po- |
sition and a lower level which causes 5 4
TO assume its lower position.