IMPROVEMENTS IN VENTILATING DRAINS AND SEWERS, AND IN THE MEANS OR APPARATUS EMPLOYED THEREFOR "
Year: 1877

page_text: LETTERS PATENT to Robert Meldrum, of Edinburgh, in the County of Mid
Lothian, North Britain, for the Invention of "IMPROVEMENTS IN VENTILATING
DRAINS AND SEWERS, AND IN THE MEANS OR APPARATUS EMPLOYED
THEREFOR
"
PROVISIONAL SPECIFICATION left by the said Robert Meldrum at the
Office of the Commissioners of Patents on the 24th October 1877.
ROBERT MELDRUM, of Edinburgh, in the County of Mid Lothian, North
Britain. "IMPROVEMENTS IN VENTILATING DRAINS AND SEWERS, AND IN THE
MEANS OR APPARATUS EMPLOYED THEREFOR."
This Invention has for its object the ventilating of drains and sewers in sections
by down-cast shafts or pipes, and hoods at top, for the purpose of diluting the gases
and forcing them up the ordinary ventilating pipes to the tops of houses, or by
utilizing the existing drain pipes and soil pipes for that purpose, carried up to the
top, either with or without discharge hoods, but fitted with proper luting or water
traps to prevent the escape of the gas into the houses.
And the nature and novelty of the Invention consist in fitting these down-cast
shafts at sufficient intervals along the main or feeding sewers from their higher
levels down to their outlet, and of sufficient size that the air passing down each
would dilute the gases and ventilate the whole section of the sewer by forcing them
up the said uptake shafts or pipes of the houses, backwards or upwards between it
and the next in succession, and so on throughout the whole system of sewerage to
the highest level.
Each down-cast shaft would preferably be formed of a short outer socket piece,
with a curved flange below for jointing over the drain pipe or sewer, and with a
flange or socket on top for securing the hood or inducing down-draught mouth-piece
by screw bolts or snugs; and these hoods might be so attached at the top of the
said short socket pieces, or to the top of pipes or shafts led up from these to any

page_text: height where the air is desired to be conducted down from, and they might be sur-
rounded by brick shafts led up to the surface of the ground, or the sides or walls
of buildings, and have gratings fitted above or in front of them, and which hoods
when fitted close to the drain would preferably have its lower end formed as a
spigot piece inserted down through the socket piece, and contracted at the lower
open mouth, either fitted with a hanging valve lid or not, which would divert the
current of fresh air backwards towards the next higher section up the said uptake
pipes, the socket piece having longitudinal recesses for receiving the projecting part
of the lower valve hinge when that is used. These hoods would each be formed
with an open mouth, projecting and widening out laterally at the top, or at any
desired angle, to its axis or centre line, to catch and direct the outer currents of air
down through the hood and the down-cast shaft into the drain, as herein-before
stated, in whichever position the hood is placed, and each open mouth would pre-
ferably be fitted with a hinged oscillating light valve or vane, which would allow
the entrance and passage of the air current down through the hood and down-cast
shaft, but which would close immediately any return or upward current of sewer
gases takes place; or other supplementary oscillating valves and vanes may be fitted
below the valve at the open mouth for the better directing and insuring of the down
current and prevention of any back current, these valves being preferably hung on
oscillating balance or scale-beam centres to ensure easy action and prevent their
becoming stiff by corrosion or dust.
-
These hoods and down-cast shafts are preferred to be made of light cast iron, but
they might be made of fire-clay, such as used for drains.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Meldrum in the Great Seal Patent Office on the 20th
April 1878.
ROBERT MELDRUM, of Edinburgh, in the County of Mid Lothian, North
Britain. "
IMPROVEMENTS IN VENTILATING DRAINS AND SEWERS, AND IN THE
MEANS OR APPARATUS EMPLOYED THEREFOR."
My said Invention has for its object the ventilating of drains and sewers in
sections by down-cast shafts or pipes 1 and hoods A at top for the purpose of
diluting the gases and forcing them up special or ordinary ventilating uptake
pipes 2 to the tops of or above the houses (or the existing vertical drain or soil
pipes 3 may be used and carried up for that purpose), either with or without
discharge hoods 31 on the top, but in all cases fitted with proper luting or water
traps C to prevent the escape of the gas back from the one section to the other, or
from the main drains or sewers into the houses.
And in order that the nature and novelty of my said Invention and the several
modifications for carrying out the improvements thereof may be properly under-
stood, I shall now proceed to describe the several Figures on the Sheet of Drawings
which I have hereunto appended, for the purpose of showing the best modes and
'means I am at present aware of for putting the Invention into effect or practice,
the same reference letters and numerals indicating the same or like parts in all the
Figures where shown.
Figures 1 and 2 are a sectional elevation and ground plan respectively of one
arrangement of my improvements as applied to one house main drain B¹¹ in contra-
distinction to a street drain or sewer, and two vertical soil or discharge pipes 3 from
the two sets of baths or waterclosets of a three-story double house or tenement, all
constructed in accordance with and illustrative of the improvements of my said
Invention as applied thereto.
Figure 3 is a sectional elevation of a main street drain or sewer B, all fitted in
accordance with and illustrative of one modification or arrangement of my improve-
ments for ventilating three drains or sewers in sectious; the drain B being broken
away at B' for want of room in the Sheet to show the full length of a single section,
which may be some hundreds of yards in length, as found most convenient.
Figures 4 to 9 show large detailed views of three different constructions of my
improved down-draft ventilating hood for fitting on the down-draft shafts or ducts
for my new system of ventilating the main street and house drains, all as will
herein-after be more fully described.
Figures 10 and 11 are a sectional elevation and a plan of a fire-clay faucet or
joint ring piece for jointing my improved down-draft shafts or improved hoods to
the main street or house drains B.
Referring to Figure 3, the nature and novelty of the first part of my said Inven-
tion consist in fitting the down-cast shafts 1 at suitable intervals along the main
street drains or sewers B as to form them into sections from the higher levels down
to the outlet discharge, and of sufficient size, that the air passing down each shaft 1
and hood A would dilute the gases and ventilate the whole section of the sewer B
by forcing them up the uptake shafts or pipes 2 fitted at the highest end of the
section, backwards and upwards between and throughout the whole section towards.
the next in succession, all as indicated by the arrows, and so on throughout the
whole system of sewerage so arranged to the highest level. Thus by this new
system of sectional ventilation and drainage each section B of the main street or
house drains is fitted with an ordinary water or dip trap C having a central close or
grated cleaning duct c, or it might be other water luted trap or screen at the lower
discharge part of the drain, separating and cutting off the section from the sewer
gases beyond, and having fitted close to and on the upper side of this trap C a down-
cast shaft 1 and hood A, Figures. 1, 2, and 3, and shown in sectional detail in

page_text: Figures 4 to 9, an uptake shaft or pipe 2 or 3 being fitted at the upper part of the
section of the main drain B, and led up so as to carry off the foul gases therefrom
above the houses; or in the case of the main drains, they might be led up into the
'stalks or chimneys of public works or others for the purpose, while for the house
drains the soil, or waste, or rain-water pipes 21 and 3, Figures 1 and 2, may be used
for this purpose when their joints are made fluid-tight, and either fitted with
ordinary discharge ventilating hood 3' or not, as desired.
In the case of main street drains the intermediate section, as shown in Figure 3,
would always be separate from the section above, and running into it by a water
trap or screen, as shown at C', to prevent the gases passing back from the one
section to the other, the arrows in these Figures indicating the current of the air
and gases, and the darts the flow of the liquids through the drains.
Referring particularly to Figures 1 and 2, which show my improvements as
applied to house drains; in this case it is a composite house or double three-story
tenement that is shown, with one main outlet drain B to both divisions of the
house, and their respective sets of waterclosets 5 and baths 6 erected over each
other in a separate division or tunnel 7 of each building. This main drain has a
water trap or screen, shown at C, which entirely cuts it off from the back flow of
the gases of the street drains, a hood A¹ being fitted close thereto, at the down
cast 1, near the side or front of the building, and an uptake shaft 21 at the back
end of the drain led up to the top of the house to ventilate this main part B₁ of
the drain, which has a trap C2 and hood A2 fitted on its two continuations' B² to
separate and ventilate the sections beyond, while another trap C¹¹, and hood A¹¹¹,
and C3, A3, are fitted on the sectional drains B1 and B³ leading from the soil or
waste-water pipes 3111 of the two sets of waterclosets and baths, which have each
their ordinary discharge pipes and U or dip traps 5 and 6" leading from them to
the discharge pipes 3111 and fitted with ventilating branches 411 leading from their
highest point to carry the gases from these direct to the discharge pipes 3111, which
are shown as carried up to the top of the roof outside the house to ventilate the
sections B, B³, and pipes leading thereto, all as seen and indicated by the arrows
and darts in these Figures.
Referring to the construction of the new down-draft hoods A for the new sectional
ventilation of drains, Figures 3 to 9, each downcast shaft 1 is by one arrangement
formed of a short outer socket piece a; when this and the hood A proper are formed
of iron, as shown in vertical, sectional, and front elevation in Figures 4 and 5, with
a curved flange a¹ below for jointing over the hole for the purpose formed in the
drain pipe or sewer B, with a flange a¹¹ on top (or it might be a socket), for securing
the hood or down-draught mouth-piece A by a flange and snugs, pins, or screw bolts
at a, and these hoods A might when desired be so attached to the top of the said
short socket pieces a, or direct to the top of pipes or shafts 1 led up from these to
any height where the air is desired to be conducted down from, and they might be
surrounded by brick shafts led up to the surface of the ground, or the sides of walls
of buildings, and have gratings fitted above or in front of their open mouths, as
at A¹; and these hoods when fitted close to the drains B would preferably have
their lower end formed as a spigot piece A" inserted down through the socket
piece a and contracted at the lower open mouth A", either fitted with a hanging
angled closing valve lid at A2 or not, and which would divert the current of fresh
air backwards (towards the next higher section), up the before-mentioned uptake
pipes 2 or 3, the socket piece a having longitudinal recesses at a² for receiving the
projecting part of the lower valve hinge when that is used.
The hoods A would each preferably be formed with an open mouth A', projecting
and widening out laterally at the top, or at any desired angle to its axis or centre
line, to catch and direct the outer currents of air down through the hood and the
down-cast shaft 1 into the drain B, as herein-before stated, in whichever position
the hood is placed.
Each open mouth or hood A would preferably be also fitted with a hinged
oscillating light valve or vane A³ hinged by steelyard, scale-beam, centres, or pivots

page_text: above, and which would allow the entrance and passage of the air current down
through the hood and down-cast shaft 1, but which would close immediately any
strong return or upward current of sewer gases or flow of the water rising in the
drains B took place, either with or without deflecting-angled flutes or surfaces A¹¹¹,
which would make the back current act more directly on the back of the valves A³
to close them.
Figures 6, 7, and 8 show a vertical section and a side elevation and plan of the
joint part of a slightly different construction from that shown in Figures 3 to 5
of my new sectional ventilating down-draught hood A for main drains. In this.
case the hood A is shown as formed with an extra closing back-current valve A*
or vane hinged horizontally, which would insure the down current of air from
the outside, but close by the up current against the lower end of the valve A³
and effectually close both, which when the back current ceases would fall to
their normal open position again against their stop pins A.
The hood is shown as jointed to a ring, socket, and snugs, a³ on the top flange
of the down-take shaft or pipe 1 by corresponding sungs a³ and pins ali at its
lower end, otherwise it is much of the same construction as that shown in Figures 4
and 5, all so far shown as made of light cast iron.
These improved down-cast hoods may also be made in a simple form, of metal or
fire-clay, of a plain round down-cast pipe or stem A, as shown in sectional elevation
in Figure 9, with a plain flange, or it might be spigot end at A* for being
inserted into an improved fire-clay faucet joint ring piece a*, shown in edge
section and plan detached in Figures 10 and 11.
The hood at the upper end would be fitted with a light india-rubber or
other ball valve A³ resting on cross arms a³, guided in the centre by four
vertical side feathers a so as to close up the inlet air hole formed in the
lower flange or socket part A of a perforated domed cowl A7 fitted and secured
by side pins on to the upper end of the hood shaft A; the outer air from
whatever direction it may be coming would enter these perforations in the
top A7 and pass down through the opening in the valve seat A6 into the drain
or sewer into which it was fitted, all as herein-before described, and indicated
by the arrows in the Figures. When the back current of water rises in the hood A
from any overflushing of the drains the ball valve A³ would float up and prevent its
escape, and fall back and open as soon as the water subsided.
It is to be understood that other forms or constructions of down-draught hoods
may be used for this sectional ventilation of drains, but these are the forms I have
found to answer the purpose best.
This sectional system of ventilating drains insures,-
1st. The complete severance of the house drains from their main drains and cess-
pools, and also from the street or public drains, by the use at each section of a trap
and down-cast ventilating hood with the soil and rain pipes used as up-cast venti-
lating shafts for the house drains, and new or special up-cast shafts for the street or
public drains quite separate and distinct from the house uptake ventilating pipes.
Special pipes D are preferred for conducting the fresh air to the new sectional
ventilating hoods placed in air wells or chambers E within the houses.
2nd. This sectional system insures the complete and separate through ventilation
of the main drains of houses, especially necessary for or in compound dwellings..
3rd. The complete and separate ventilation of each tier of soil pipes for the
different dwellings, each by its own trap and down-cast ventilating hood.
4th. The complete ventilation of the main street drains or public sewers in
sections separately from the house sewers.
Having now described the nature of my said Invention and the manner of
performing the same, I have to state that I do not confine myself to the precise
details herein described or delineated; but what I consider novel and original,
and therefore claim as the Invention secured to me by the herein-before in part
recited Letters Patent is,-
First. The general system or mode and means of ventilating public drains and

page_text: house drains in separate sections, distinct from each other, by the combination and
use of a water-luting trap, down-cast air hood, and up-cast shaft, for each section,
all substantially as herein described in reference to, and shown in the accompanying
Drawings, or any mere modification thereof.
Second. The severing of house and main drains into sections by the use of a
water-lute trap and down-cast air hood at the one end, and uptake air shaft at the
other end, all substantially as herein described in reference to, and shown in the
accompanying Drawings, or any mere modification thereof.
Third. The construction and use of new or improved down-cast air ventilating
hoods and their fittings for the sectional ventilating of main house drains, and street
or public drains, all substantially as herein described in reference to, and shown in
the accompanying Drawings, or any mere modification thereof.
In witness whereof, I, the said Robert Meldrum, have hereunto set my
hand and seal, this Seventeenth day of April, One thousand eight hundred
and seventy-eight.
ROBERT MELDRUM. (L.S.)