Improved System of Ventilating Sewers, and Apparatus therefor.
Year: 1899

page_text: Date of Application, 19th July, 1899
Complete Specification Left, 19th Apr.. 1900-Accepted, 19th May, 1900
PROVISIONAL SPECIFICATION.
Improved System of Ventilating Sewers, and Apparatus therefor.
We, GOMER SWEETING MORGAN, of Llantrisant Road, Pontyclun, Glamorgan,
Civil Engineer, and WILLIAM WILLIAMS, of Bryn-Derw, Plymouth Road,
Penarth, Glamorgan, Doctor of Medicine, do hereby declare the nature of this
invention to be as follows:-
This invention, which relates to ventilation of sewers, consists in an
improved system and apparatus therefor. It has for its object to supply fresh
air to sewers by means of shaft inlets and the prevention of escape of sewer gas
and foul air by way of such inlets.
According to this invention, ventilation is effected by means of specially
designed shafts or tubes erected at such distances apart as may be desirable or
necessary. Each ventilating shaft consists of an open-topped tube provided
for the outlet of sewer gas and foul air into the atmosphere from the open top,
and an outer fresh air inlet tube concentric with the outlet tube and extending
upwards from the base of the latter and terminating at a suitable height vary-
ing with circumstances, but always below the top of the sewer gas or foul air
outlet tube. At its top the fresh air inlet tube carries a bonnet, in the sides of
which are formed grids or gratings against the inner faces of which bear flap
valves or doors of mica or aluminium or other suitable substance. These flap
valves or doors are hung at the top on hinges or pivots and when in their normal
positions they close the grids or gratings.
Below the ground level the outlet tube communicates by a nozzle or branch
with the usual sewer man-hole in which latter is, as usual, a flap valve or door
to the sewer, which door, while opening to the flow of sewage, obstructs the
passage of gas and foul air to the section of sewer beyond it. On the opposite
or another side the fresh air inlet tube similarly communicates with the sewer
continued from the manhole.
While the pressure from without exceeds that within the fresh air inlet tube,
the mica or aluminium flap valves in the bonnet are open and the fresh air
passes down into the sewer, driving the sewer gas and foul air along a section
of the sewer and escaping at the open top of the outlet tube of the shaft next in
succession in the series.
On the occurrence of a down draught in the outlet tube of a shaft and the
creation of a preponderating pressure from within, the mica or aluminium doors
of the inlet tube of the shaft next in succession in the system of ventilation
close, and so prevent the escape, by way of the inlet grids or gratings which they
control, of the sewer gas and foul air driven back by such down draught.
Dated this 18th day of July 1899.
NICHOLAS WATTS,
Chartered Patent Agent Bristol.

page_text: Improved System of Ventilating Sewers, and Apparatus therefor.
We, GOMER SWEETING MORGAN, of Llantrisant Road, Pontyelun, Glamorgan,
Civil Engineer, and WILLIAM WILLIAMS, of Bryn-Derw, Plymouth Road,
Penarth, Glamorgan, Doctor of Medicine, 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:-
This invention consists in an improved system of ventilating sewers, and in
apparatus for practically carrying the system into effect.
Under the system of sewer ventilation as effected according to this invention,
sewers are divided into sections by swing doors or flap valves situated at arranged
distances apart at man-holes or "lamp" holes. The swing doors or flap valves
open in the direction of the flow of sewage and obstruct or partially obstruct
the passage of sewer gas and foul air from one section of a sewer into the section
beyond it. Each section is provided with a ventilating shaft constructed and
arranged according to our invention. The terminal sections of sewers have, as
hitherto, an ordinary foul air extract shaft and these terminal sections are sup-
plied with fresh air from one of our improved ventilating shafts. Our improved
shafts, which are of cast-iron or steel, are erected at such distances apart as may
be desirable or necessary. Each ventilating shaft consists of an internal tube
provided for the outlet of sewer gas and foul air, and an outer tube surrounding
and concentric with the internal tube. The outer tube is the fresh air inlet.
Both tubes extend upwards from a base-plate common to both which plate is
bolted or otherwise fixed on a suitable foundation situated below ground level.
The internal tube is extended to a greater height than the outer tube and is
open at top to the atmosphere. The outlet tube should be extended up con-
siderably higher than the inlet tube so as to discharge well clear of the inlet.
The inlet tube terminates in a bonnet which has no communication with the
internal tube. In the sides of the bonnet are fitted and secured grids or gratings.
and behind these grids are flap valves of mica, aluminium or other light and
suitable substance. Each flap valve is hinged or loosely suspended at top to
the frame of the grid to which it appertains. When the flap valves are in their
normal position they lie closely against the inner faces of the grids, blocking
outlet from the bonnet. Below the ground level the outer tube is branched and
so communicates with the sewer. The inner tube is also branched and so com-
municates with the manhole.
While the pressure of the atmosphere acting from without against the flap
valves in the bonnet of the inlet tube exceeds the pressure exerted upon them
from behind, the flap valves are tilted back to the open position, and thus the
fresh air passes down into the sewer, driving sewer gas and foul air along a
section of the sewer to the outlet tube of the shaft next in succession in the
series.
On the occurrence of a down draught in the outlet tube of a shaft and the
creation of a preponderating pressure from within, the flap valves or doors in the
bonnet of the inlet tube of the shaft next in succession in the system close upon
the inlet grids and thus prevent escape, by way of the said inlet grids, of the
sewer gas and foul air driven back by such down draught.
Referring to the accompanying sheet of drawings, Fig. 1 is an elevation of a
sewer ventilating shaft as constructed in accordance with this invention. It
is adapted for extracting sewer gas and foul air from one section of sewer and
supplying fresh aid to two sections of sewer. In the lower part of the fig. the

page_text: shaft is shown so as to bring the foul air outlet branch a¹ directly in front.
Fig. 2 is a vertical section, the upper part corresponding to the upper part of
Fig. 1, but the lower part turned so that the foul air outlet branch is at the
back. Fig. 3 is a plan of the top: Fig. 4 a transverse section on the line x, x,
Figs. 1 and 2. Fig. 5 is a transverse section on the line y, y Figs. 1 and 2.
Fig. 6 is a transverse section taken above the junction of the branches, a and b,
for connection of the shaft to the sewers. Fig. 7 is a diagrammatic plan showing
an arrangement of connection between a shaft and sewers. The work under-
ground is shown dotted. Fig. 8 is a diagrammatic vertical section on the
line z,, Fig. 7.
Our improved ventilating shaft, which is of cast-iron or steel, consists of an
internal tube a by which foul air and sewer gas are discharged into the atmos-
phere, and an external tube surrounding and concentric with the internal
tube a.
The tube is the outlet conduit by which sewer gas and foul gas pass
up from the sewer. The tubes a and b extend upwards from a common base-
plate bolted or otherwise fixed on a suitable foundation situated below ground
level. The foul air outlet tube a is continued up by extensions to a greater
height than the fresh air inlet tube b and is open at top to the atmosphere. The
tube a should be carried up considerably higher than the tube 6 so as to dis-
charge at a proper elevation above the fresh air inlets to the tube b. The tube b
is, in the example of shaft illustrated in the accompanying drawings, arranged
for supplying fresh air to two separate sections of sewer, as seen at Figs. 7 and 8
in which the direction of current of fresh air is indicated by the arrows A. The
arrows A indicate the direction taken by the sewer gas and foul air. The
arrows A2 indicate the direction of flow of sewage. For this purpose the shaft is
divided vertically by the partitions which extend throughout its length. The
tube terminates at top with a bonnet which has no communication with the
tube .
In the bonnet & are fitted gratings or grids e behind which are flap
valves or doors f of mica, aluminium or other suitable substance. Each valve f
is hinged or loosely suspended at top, as at to the frame of the grid to which
it appertains. When the valves f are in their normal positions, as shown in.
the drawings, they lie closely against the inner faces of the grids e, thus block-
ing outlet from the bonnet d.
Below ground level, which is indicated by the line G, G, Figs. 1, 2 and 8,
the tube has branches b' leading to two separate sections of sewer. The tube a
has a branch a¹ for connection of the shaft to the manhole. The branch a¹ is
carried through the wall of the tube b.
By the pressure of the atmosphere acting from without, the valves or swing
doors in the bonnet dare tilted back to the open position and the fresh air
thus admitted passes down the divided tube and is led off by the branches b¹
to the respective sections of sewer, driving the sewer gas and foul air in the
sections along such sections to the outlet tube of the ventilating shaft next in
succession in the system, or to a terminal shaft.
On the occurrence of a down draught in the outlet tube a of a shaft and the
creation of a preponderating pressure from within on the grid valves of the
bonnet of the inlet tube of the shaft next in succession in the system, the valves
of such next shaft close upon the inlet grids of the said bonnet and thus prevent
the escape, by way of the said grids, of the sewer gas and foul air driven back
by such down draught.
By further dividing the tube b into more divisions, fresh air can be supplied
from the tube to further sections of sewers.
Having now particularly described and ascertained the nature of our inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is:-
1. A system of sewer ventilation, according to which the sewer is divided by

page_text: .swing doors into sections and each section is furnished with a ventilating shaft;
the arrangement being such that the sewer gas and foul air in any one section
pass out through the shaft appertaining to such section and fresh air is admitted
to the sewer by the same shaft; but through a separate tube or conduit, the inlets
to which become closed on the creation in the sewer section of a back draught
and a preponderating pressure, substantially as hereinabove described.
2. A ventilating shaft for sewer ventilation, comprising an internal tube
such as a for discharge of sewer gas and foul air, and an outer tube such as b
for admittance of fresh air; the two tubes having no connection with each other
in the shaft and the said tube being fitted with a bonnet or head such as d
having grated inlets, or the like, behind which are swing valves or doors such
as f, which valves or doors open to admit air to the inlet tube so long as the
pressure from without exceeds that from within, but close the inlets when a back
draught of preponderating pressure is created behind them, substantially as
hereinabove described with reference to the accompanying drawings.
Dated this 18th day of April 1900.
NICHOLAS WATTS,
Chartered Patent Agent Bristol.