Year: 1888

page_text: GEORGE HENRY LOCK, No. 54 Richard's Terrace Roath Cardiff, Inspector of Works,
do hereby declare the nature of this invention to be as follows:―
To allow of the free access of fresh air into the drain, and the total prevention
of foul air escaping from the drain.
Fig. 1 is a Front Elevation, and Fig. 2 a Sectional Elevation. A and B is a movable
cap placed over the top of the box; the part A being perforated on two or more sides
to allow of the passage of air. The part C is of the same cross section as that of
the Ventilating pipe into which the Ventilator is fixed. D D is a tale valve fixed to
a horizontal brass rod P which does not pass through the centre of gravity of the
tale valve. N is a bracket in which the brass rod P is free to move. F is a plate
fixed to the back of the box, and it supports the valve when in the position shewn.
In this position it is open and allows the fresh air to pass freely into the drain in the
direction shewn by the arrows.
For the prevention of any back-draught a plate E is fixed to the back of the box
which reflects the foul air to the talc valve D. D. closing it against two pieces of
angle zinc G fixed to the sides of the box, and thus preventing any escape of
foul air.
The advantages claimed for this invention are:-
(a) The valve D D is always open for the admission of fresh air (except during a
back draught) this is not the case with valves hung vertically which during wet
weather are held by capillarity to the box.
(b) The valve D D being hung almost in the centre of the pipe, with one extremity
over the side of the pipe, is extremely sensitive to the pressure of any back draught,
the whole force of which is utilised in closing the valve by the arrangement of the
plate E.
1000

page_text: COMPLETE SPECIFICATION.
A Fresh Air Inlet and Back Draught Preventer for Ventilating
Drains.
I, GEORGE HENRY LOCK, of 54 Richards Terrace, Roath, Cardiff, in the county
of Glamorgan, Inspector of Works, 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 apparatus for admitting fresh air and preventing back draughts in the
ventilation of sewers to which this invention relates, consist in a chamber communi-
cating with the sewer and surmounted by a perforated cap.
Pivotted in the chamber is a valve which governs the communication with the
sewer and with the atmospheric air.
This valve is so balanced on its supports that it normally lies open admitting fresh
air to the sewer.
On the occurrence, however, of a back draught proceeding from the sewer the valve
tilts under the influence of such back draught and, closing the communication with
the sewer, prevents the escape, by the ventilator, of foul air or noxious gases.
Referring to the drawing left with my application with a Provisional Specification
for Letters Patent to this invention, Fig. 1 thereon represents a front elevation, and
Fig. 2 a vertical section of my improved apparatus for admitting fresh air to sewers
and for preventing the escape therefrom of back draughts.
Below the perforated cap A which surmounts the apparatus is a chamber in which
is a valve D, pivotted at P, the pivots being supported in brackets provided at both
sides of the chamber.
The valve D, which may be of talc or other suitable substance, is so balanced
that, it normally lies open, as shewn in the drawing, for the admission to the
sewer of the fresh air entering at the cap A.
In this position the upper end of the valve bears against the stop plate F fixed
to one side of the valve chamber. When a back draught occurs in the sewer with
which the ventilating pipe C communicates, the valve D which is of a light nature,
is tilted under the influence of such draught, which effect is assisted by the baffle.
plate E fixed to the wall of the valve chamber and extending upwards at an angle to
the under side of the valve D, as shewn.
The plate E deflects the upward current so as to bear more effectually on the valve
which now assumes the position shewn at D¹ and, bearing at each side against
overhanging side pieces or ledges G fixed to the wall of the chamber, closes
communication with the cap A and, therefore, with the outer air.
It will be seen, therefore, that in the absence of any back draught from the sewer
the valve D remains open for the admission of fresh air, but closes where an upward
current occurs and so prevents the emission of foul air and noxious gases.

page_text: Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. The use for controlling the communication between a sewer and the outer air,
of a valve such as D of a suitably light character pivotted in a chamber provided
below the fresh air inlet and so balanced that the valve is normally, and in the
absence of a back draught from the sewer, open for admitting air to the sewer, but
closes against the escape of a back draught, substantially as herein before
described.
2. The use, in combinativn with the overhanging valve D, of the stop plate F, and
baffle or deflecting plate E, and the ledges G, arranged substantially as herein before
described with reference to the accompanying drawing and for the purposes
specified.