PROVEMENTS IN TRAPS FOR GULLIES, SINKS, AND OTHER PLACES
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by Richard Newman Somerville at the
Office of the Commissioners of Patents on the 7th July 1877.
RICHARD NEWMAN SOMERVILLE, of Galway, Ireland, Borough Surveyor.
PROVEMENTS IN TRAPS FOR GULLIES, SINKS, AND OTHER PLACES."
"IM-
The object of my Invention is to construct traps in such manner that while they
shall prevent the escape of all smell or gases from the sewer or drain, they shall
intercept all foreign matters which may pass through the grating; that they shall
prevent the passage into the sewer or drain of any water or liquid exceeding a
certain specific gravity, that is to say, holding more than a given amount of
dirt, grit, or other matter in suspension; that they shall readily show when a
quantity of mud or other too thick material has been passed through the grating,
or when there is much deposit in the trap; and that they can be readily cleaned
out.
My improved traps are constructed as follows:-Within a box or casing which
is covered by a grating I place a second or inner box open at the top. From an
opening in the centre of the bottom of this box I carry up a tube which is closed
at its upper end, but has holes near such upper end; over this end is fixed
a cap or hood, the sides of which extend downwards to, say, an inch below
the level of the said holes, and they do not touch the sides of the tube. This
tube fits over a corresponding tube carried up from an opening in the bottom
of the outer box, which opening leads to the sewer or drain. On the top of
the cap or hood is an eye or loop to receive the end of a lever, which has its
fulcrum on the side of the outer box, and which is weighted so as to balance
the weight of the inner box when filled up to the level of the holes in its tube with
liquid containing a maximum amount of material in suspension, that is to say, of
the maximum specific gravity.
In the normal position the inner box is raised so that the closed upper end of its
tube is clear of the upper end of the tube in the outer box, the weighted lever
retaining it in this position. The liquid which passes through the grating fills the
inner box up to the level of the holes in the tube, and then flows through the holes
. into the tube of the outer box, which conducts it to the sewer or drain; but when
the weight of the inner box and its contents exceeds that of the balance weight,
owing either to the accumulation of deposit, or to the liquid being too thick, such

page_text: as slush or mud, the box descends until the closed end of the tube of the inner box
rests on the top of the tube of the outer box, and the holes being thus covered,
nothing can pass through to the sewer. The fact that the inner box has descended
can be ascertained either by lifting the grating, or lifting a plate which covers the
lever. The inner box being at all times filled with liquid up to the level of the
holes, or nearly so, the sides of the cap before-mentioned dip into the liquid to about
the extent of an inch, so that a "seal" to prevent the escape of gases from the
sewer or drain is formed. There is also water between the boxes up to the level of
the holes, so that no escape of gas can take place through the space between the
boxes.
In order to clean out the trap the grating is raised, the lever is released from the
inner box, and the inner box lifted out and emptied. Any deposit in the bottom of
the outer box may then be removed.
Sometimes I place a tray between the inner and outer boxes to receive any
matter which would otherwise be deposited in the outer box, and this tray can
be lifted out and emptied when the inner box has been lifted out.
In some cases I substitute for the weighted lever weighted cords attached to
opposite sides of the inner box, and carried over pulleys at the sides of the outer
box.
The foregoing description applies more particularly to traps suitable for street or
road gullies, but obvious modifications will adapt such traps to sinks and other
places.