Improvements in Sewer and House Drain Traps.
Year: 1889

page_text: Date of Application, 11th Mar., 1889
Complete Specification Left, 8th Nov., 1889-Accepted, 14th Dec. 1839
PROVISIONAL SPECIFICATION.
Improvements in Sewer and House Drain Traps.
I, WILLIAM SMITH Civil Engineer St, Fountainhall Road, Aberdeen, N.B. do
hereby declare the nature of this invention to be as follows:-
The underflush trap is a water trap for sewer gas, which is cleared of humus or dirty
water by the scouring action of a jet of clean water applied directly by a pipe from an
overhead cistern to the bottom of the trap. The seal or head of water in the trap may
in consequence be increased up to 3, 4, or 5 inches as may be desired, without making
the trap liable to stoppage by choking or retaining the humus or dirty water in the
seal. In waterclosets the underflush trap may be used either in connection with a
valve trap or a wash out basin, in the latter case it renders the action less noisy. A
ventilating pipe is carried out to the main ventilator from the lower side of the trap
seal, the opening being placed where the underflush will not impinge upon it. The
principle of its action is the retention of the stream of water from the cistern at an
uniform bore or cross-sectional area to the point of application at the bottom of the
trap, thereby conserving the energy of the water for application within the trap. The
underflushing cistern for a watercloset trap may be a separate cistern attached to the
ordinary flushing cistern at the same level, and supplied with water from it by means
of an opening through the sides of the cisterns with a flap valve opening into the
underflushing cistern. The underflushing cistern is thus filled to the same level as
the flushing cistern and retains the water until the flushing cistern is emptied. A
floating weight in the flushing cistern then bears upon the end of the lever for opening
the underflushing valve, opening the valve automatically immediately before the
flushing cistern is empty and causing the under-flush of the trap. The two cisterns
may be combined in one box with a diaphragm dividing it carried up only to the
height of half an inch below the surface of the water when full, thereby dispensing
with the flap valve. The underflushing cistern is fitted with the usual after flow
chamber beneath the cistern to ensure the refilling of the trap with clean water up to
the height of the water seal after the trap has been underflushed. Or, alternatively an
additional valve may be placed in the bottom of the flushing cistern, opening into the
underflush pipe, the floating weight coming to bear upon the end of the valve lever
by a chain as the water is lowered in the cistern by the basin overflush.
The trap on the main drain connecting the house drains with the sewers may also be
fitted with a jet at the bottom of the trap to scour out the trap occasionally and
prevent stoppage of the drains by sediment in the trap. This arrangement allows the
water seal of the main trap to be increased up to 4 inches or any desirable head. The
jet would be supplied direct from an overhead underflushing cistern filled by a ball
cock off the water main. To economise water the water supply cistern for under-
flushing the outside trap may be filled from a high level bath or basin in frequent use.
The underflush jet may also be applied with advantage to traps on sinks, basins, &c. to
prevent choking with grease, soap or other solids.
3011
1000
COMPLETE SPECIFICATION.
Improvements in Sewer and House Drain Traps.
I, WILLIAM SMITH, Civil Engineer, 84 Fountainhall Road, Aberdeen, N.B. do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement :-
The underflush trap is a water trap for sewer gas, which is cleared of humus or dirty

page_text: water by the scouring action of a jet of clean water, applied directly by a pipe from
an overhead cistern to the bottom of the trap. The seal or head of water in the trap,
may in consequence he increased up to any depth that may be desired, without making
the trap liable to stoppage by choking, or retaining the humus or dirty water in the
trap. Fig. 1. represents a water closet having, in addition to the ordinary flushing rim
and pipe, a separate pipe A-A. carried down from a cistern, called the underflushing
cistern which may be either a separate cistern or a separate valve in the ordinary
flushing cistern, to the socket B in the bottom of the trap. The principle of its action
is the retention of the stream of water from the cistern at an uniform bore or cross-
sectional area in the pipe A-A. to the point of application B at the bottom of the
trap, thereby conserving the energy of the water for application within the trap
upwards from the bottom, in the direction of the arrow to sewer. The air-pipe C-
relieves any compressed air in the pipe A-A and is inserted immediately above the
surface of the water. The ventilating pipe D is inserted below the upper bend of the
trap where the underflush current will not impinge upon it. Fig. 2. represents
the underflush applied to the trap on a main house drain, A-A' is the underflush
pipe, B the socket in the bottom of the trap, the air-pipe. Fig. 3. represents the
combined flushing and under flushing cisterns, being a cistern divided into two com-
partments E, the flushing cistern, and E, the underflushing cistern by the diaphragm F.
G. is the syphon and H the lever for flushing the water-closet basin; G the valve
and H the lever for starting the underflush. The floating weight I sinks with the
emptying of the flushing compartment E. until near the bottom it bears upon the end
of the lever H by means of a chain which hangs loose while the weight I Hoats. The
rush of water through the valve G1 starts the syphon L, and the afterflow chambers K
insure the re-filling of the basin and trap with clean water after flushing and under-
flushing.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is-
The application of a jet of water directly by a pipe from an overhead cistern to the
bottom of a trap in the manner and for the purpose described above, namely, to clear
out humus or dirty water from a deep sealed trap.
That I disclaim the use of any closet or trap with apertures in any other position
than the bottom of the trap.
That I disclaim any mechanical arrangement of cistern or flushing apparatus herein
described.
Dated this Seventh day of November 1889
WM. SMITH.