An Apparatus for Testing the Efficiency of Ventilation.
Year: 1895

page_text: Date of Application, 3rd Jan., 1805
Complete Specification Left, 3rd Oct., 1895-Accepted, 28th Dec., 1895
PROVISIONAL SPECIFICATION.
An Apparatus for Testing the Efficiency of Ventilation.
I, HAROLD SCURFIELD, M.D. of 9 Rectory Terrace, Sunderland, in the County
of Durham, Practitioner of Medicine and Surgery, do hereby declare the nature
of this invention to be as follows:
A receptacle to contain water hereinafter called the aspirator, provided with a
handle; an opening at the top, and a tap near the bottom.
.. 10
the
A stopper perforated by a single opening, through which latter is pushed a short
piece of rigid tubing, fits closely the opening in the top of the aspirator. To
tap of the aspirator is fitted a piece of flexible tubing and to the latter a piece
of glass tubing of about the same length as the height of the aspirator.
Round the outside of the aspirator are attached holders to hold glasses.
A graduated scale, marked down the outside of the aspirator, indicates the
height reached by measured quantities of water inside the aspirator.
Holders are fixed alongside of the scale to hold the glass tubing connected with
the tap of the aspirator, when this glass tubing is inverted without disconnecting
it from the tap.
Glasses are made to fit the holders arranged round the aspirator, the said glasses
being intended to contain a certain quantity of an alkaline coloured liquid, whose
colour changes when it is neutralized by the passage through it of air.
any of the
A doubly-perforated stopper is made to fit closely the mouth of
glasses; through one perforation of this stopper a piece of glass tubing is pushed
so far that it reaches nearly to the bottom of the glass, while its upper end' is
projecting from the stopper and open to the air through the other perforation of
this stopper is pushed, a shorter piece of glass tubing, so that one end of the tubing
lies above the surface of the coloured liquid in the glass, when the latter has been
filled to the required' height, while the other end of the tubing is connected by a
piece of Hexible tubing with the upper end of the tubing pushed through the
stopper of the aspirator.
"To use the apparatus, the aspirator is filled with water and the glasses are filled
to the required height with the coloured alkaline liquid; the stoppers are inserted
into the opening of the aspirator and the mouth of one of the glasses respectively
the tap of the aspirator is then turned on and, as the water runs out, the air
bubbles through the coloured liquid.
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When the aspirator is empty, if the change of colour has not taken place, the
stopper is removed & it is refilled with water, the stopper is replaced and the
aspirator is donin emptied this filling and emptying is repeated until the change
of colour has taken place in the liquid in the glass. When this change of colour
Las taken place, the tap is turned off and the amount of water run off from the
aspirator is calculated, any residue of water remaining in the aspirator being
found by inverting the glass tubing connected with the tap of the aspirator &
placing it in the holders alongside of the scale, removing the stopper of the
aspirator, turning on the tap and noting the height on the scale reached by the
water in the tubing.
1226
The amount of water this calculated is the measure of the amount of air
that has been necessary to effect the required change of colour in the liquid in
44841882
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page_text: To ascertain the efficiency of the ventilation of a room or rooms, the glasses are
filled with the same quantity of the same coloured liquid: it is first noted, how
much of the outside air it takes to effect the change of colour in one of the glasses,
and afterwards, how much of the air of the room, whose ventilation it is desired to
test, it takes to effect a similar change of colour in one of the other glasses.
Dated this 2nd day of January 1895.
I, HAROLD SCURFIELD of 9. Rectory Terrace, Sunderland Physician, 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 object of my invention is to provide an apparatus by which a reliable
approximate estimate of the efficiency of the ventilation of any room may be readily
obtained.
It consists essentially in the measurement of the quantities of air inside and
outside the apartment to be examined, which are respectively necessary to decolorise
equal quantities of a solution which changes colour when ordinary air is passed
through it in proportion to the amount of carbonic acid or other gaseons impurity
contained in such air.
In order that my invention may be the better understood reference is made to
the accompanying drawing which represents a general view of my apparatus in the
form which I have found most convenient.
On this drawing A represents a cylindrical vessel or aspirator furnished with a
stoppered opening at top (not shewn on drawing) and with a plug B which fits into
a second opening at the top and is provided with a tube b by which air-tight
connection can be made between the aspirator and adjacent vessels.
The aspirator A is furnished with a number of holders C C, into which fit glass
tubes D, furnished with air-tight stoppers E, and with a single graduation towards
their upper end to indicate an equal capacity of liquid up to the graduation in all
of them. These stoppers are each fitted with two tubes, one of which F is straight
and extends nearly to the bottom of the tube D and projects into the open air, the
other G only projecting a little way into the tube and being furnished with a bend
for connection to the aspirator A by means of a piece of rubber-tubing, a plug, or
any other joint readily to be made or broken. The tubes F are preferably closed
at bottom and furnished with perforations of approximately equal area; or they
may be drawn down to a point to approximately the same diameter in each case.
A tap H is provided near the bottom of the aspirator, on the lower end of which
is fixed a piece of rubber tubing provided with a piece of glass tubing at its end.
A vertical graduated scale is marked down the outside of the aspirator at this
point. The aspirator is fitted with a handle and provided with a case, preferably
having a slotted cover through which the handle may project.
When it is desired to test the efficiency of ventilation of any room or number of
rooms, the necessary number of tubes D are filled up to the graduations with the
solution to be decolourised. The strength of this solution is immaterial, provided
the same is used for all the tubes. The aspirator A is filled with water and is
connected through the tube 6 with the tube Ġ of any of the tubes containing the
liquid. The cock H is then opened, and as the water flows out, air is drawn in
at F through the liquid in the tube; the opening of the tap and the approxi-
mately equal area of the perforations at the bottom of the tube ensuring that the
air will pass through the liquid at approximately a constant rate and in bubbles of

page_text: approximately the same size, whichever tube may be used. The water may for
convenience be allowed to fall into the case. If the liquid is not entirely
discoloured when the aspirator is empty, the water is put back into the aspirator
and drawn through again until discoloration is effected. When this has occurred,
the quantity of water left in the aspirator is measured by inverting the glass tube
and holding it against the scale on the outside of the aspirator; and the amount of
water which has passed through the aspirator becomes the measure of the quantity
of air which has been required to effect discoloration. The same process is then
gone through with other tubes in each of the rooms to be examined, and the
As these
quantity of water taken to effect the discoloration is noted in each case.
quantities correspond to the quantities of air which have respectively passed
through the tubes in the outer air and in the rooms, and therefore to the amount of
carbonic acid or other gaseous impurity which the air in these positions respectively
contained, the quantities of such carbonic acid or gaseous impurity will be inversely
proportionate to the quantities of water which have been employed.
The solution which I prefer in the case of carbonic acid, but to which I do not
necessarily restrict myself, is phenolpthalin clarified by the addition of alcohol
and rendered alkaline by a few drops of barium hydrate. The same liquid can
therefore be used over and over again. To make sure that the solution in the
tube under examination has been completely discoloured, I prefer to look at it.
lengthwise from time to time.
Instead of the scale of the aspirator being read by means of the glass tube
at the end of the rubber tube, I may fix a graduated gauge at the side of the
aspirator.
I am aware that the decolorisation of liquids has been used as a means of
estimating carbonic acid in gas analysis; but
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 apparatus for estimating the efficiency of ventilation by the comparison of
the proportion of carbonic acid or other gaseous impurity in the air examined to
that contained in the outer air as described.
Dated this Third day of October 1895.
Dated this Third day of October 10
For the Applicant,
GEDGE & FEENY,
Agents.