Omaha daily bee., 1909-05-10
AFFAIRS AT SOUTH OMAHA
Sewer Contractors Complete Com
pressed Air Locks on N Street.
WoRKMEN PROCEED IN COMFORT
How the Locks Are Constructed and
Method Of Navigating Interior
is Described in Some
Detail.

The contractors, Harmon & Craig, have
completed the work of installing the COM
pressed air locks in the tunnel Of the n
street gulch sewer and the men are work
ing in the tunnel in a comparatively dry
plaIe where before streams of running
water and muck made progress impossible,
The compressed air forces all water back
through the soil. 1t also serves to hold
up the loose clay and permit the men to
work without great danger of caving. The
system of locks consists simply Of an outer
and inner chamber. The outer chamber is
as small as possible for convenience, The
size of the inner chamber is limited only
by the length of the tunnel which is being
constructed, Air is pumped by a COM
pressor into the inner chamber until the
desired pressure is reached. The men
within can work then until it becomes
necessary to communicate with the outside.
In order to get into the tunnel one must
enter the outer chamber or lock. The lock
ter der then warns the novice to keep his
hands off his ears and to pinch his nose
The door communicating with the outer
world is closed and the tender opens the
valve connecting the outer and inner
chambers. A tremendous kissing follows
as the air within pours into the outer
chamber.
Pinch Nose and Blow.
Soon the change in pressure Is felt on the
drum of the ear and great pain follows UNI
less the man is prompt i'm pinching his nose
and blowing hard with his breath so as to
force air into the eustachean tubes of the
middle ear. If he follows directions and
blows vigorously suddenly the tubes of the
ear open and the air can be felt rushing
into the ear. Great relief follows. This
act must be repeated many times as the
pressure increases. Soon the kissing of
the valve ceases, which shows the pressure
in the lock and in the working chamber
is the same. The gatetendcr knocks on the
inner door and the workmen within open
il. The visitor is then able to walk into
the tunnel, lie feels no more the pain in
his ears and is entirely unconscious of the
extra atmosphere of pressure. The tun-
mel is seen to be dry. When he wishes TO
go out he goes into the lock again and
closes the door between IL and the work
ing chamber. Then the valve between the
two is closed and the valve between the
lock and the outer world is opened. At
once the chamber is filled with dense
steam due TO the condensation of watery
vapor as the pressure is rapidly dimin-
ished and the air expands, suddenly low
ering the temperature TO the condensing
point. The visitors ears feel
able again, but the pain is not severe, as
the compressed air OF the middle ear easily
forces its way out.
The soil through which the contractors
are attempting to lay the tunnel Is very
hard TO handle. 1t is made soil and is
mostly ~decuJuposed residue OF thousands
of loads Of debris and waste from the
Union stock yards. This manure was
dumped in the n street hollow many years
ago. The soil is therefore very treacherous
and progress is slow. This was the reason
! the water was so troublesome at this point
y. NJ. &. A.. Notes.
A called meeting will be held Monday