THE COLLIERY GUARDIAN

AND JOURNAL OF THE COAL AND IRON TRADES.

Vol. CV.

THURSDAY, MARCH 20, 1913.

No. 2725.

oxygen cylinders and regenerator and the back of the
wearer, which envelope is inflated to the required extent by
the pressure inside the apparatus, and remains inflated so
long as there is no leak on the apparatus. The moment that
a leak occurs, the envelope ceases to be inflated, and the
wearer is at once conscious that something has gone wrong.
In ordinary working, the air in the reservoir or bag main-
tains a plus pressure throughout the apparatus.

In connection with the question of injector versus non-
injector apparatus, the author referred to the first real
form of pneumataphor that was used on a practical scale,
the invention of Chevalier Walcher-Uysdal, of Teschen,
Austria. From this original type of pneumataphor those
of the present day have been evolved. The first improve-
ment was to put the oxygen cylinder on the back of the

MIDLAND INSTITUTE OF MINING, CIVIL,
AND MECHANICAL ENGINEERS.

Meeting at Barnsley*

A meeting of the Midland Institute of Mining, Civil
and Mechanical Engineers was held in the T.M.C.A.
hall, Barnsley, on March 12. The President (Prof.
F. W. Hardwick) occupied the chair, and there was a
large attendance.

The first business was the alteration of Rule 7, which
deals with the admission of new members. Hitherto it
has been provided that the nominations shall be made
at a general meeting, and shall then be hung up in the
room of the institute for one month, after which the
names of the proposed new members are submitted for
election. This practice, however, has not been strictly
adhered to, a somewhat better method having been
observed. The altered rule (which was adopted on the
motion of the president), provides that the nominations
shall first be submitted to the council (in order that
that body may see that the members are nominated for
their proper classes) and then sent on a printed paper
to all members of the institute, the election taking
place at the next general or special meeting.

The following elections were made:—Members: Mr.
John Dutson, Rotherwood, Handsworth, near Sheffield,
proposed by Mr. F. J. Jones, seconded by Mr. G. Blake
Walker; Mr. John Ensor, Tinsley Park, Sheffield,
proposed by Prof. L. T. O’Shea, seconded by J. H. W.
Laverick; Mr. Arthur Leonard Flint, H.M.I.M.,
25; Hilton-road, Harehills, Leeds, proposed by Mr.
James Mellors, seconded by Mr. Joseph Greensmith;
Mr. Tom Jefferson Fryer, Celtic Works, Savile-street
East, Sheffield, proposed by Mr. A. Blenk insop, seconded
by Mr. E. W. Thirkell; Mr. Charles Haswell, 135,
Machon-bank, Sheffield, proposed by Mr. A. J. Creswick,
seconded by Mr. J. Brass; Mr. John Edwin Tongue,
Poplars, Kimberworth, Rotherham, proposed by Mr. G.
Blake Walker, seconded by Mr. Harry Rhodes; Mr.
Robert Colin Snow, The Cedars, Victoria-road, Mexbro,’
Rotherham, proposed by Mr. Arthur T. Thomson,
seconded by Mr. Jonathan Wroe. Associate member :
Mr. Thomas Cardwell Wild, 9, Lismore-road, Sheffield,
proposed by Mr. Jonathan Wroe, seconded by Mr.
Joshua Rawlin. Student member: Mr. Charles Edward
Routh, 2, St. Sepulchre-gate, Doncaster, proposed by
Mr. H. St. J. Durnford, seconded by Prof. L. T. O’Shea.

The President announced that Mr. D. Bowen and
Dr. Coplans, of Leeds University, who had promised to
give a note on an electrolytical method of determining
the percentages of various gases in mine air, regretted
that they were unable to do so, as they had, unfortu-
nately, been prevented by lack of time from carrying
out some experiments which they wished to make in
order to confirm results previously obtained. Their
note would be given later on. He called upon Mr.
Harold 0. Jenkins to read his paper on “Some
Recent Experiments with Internal Pressures in
Pneumataphors.”

Internal Pressures in Resue Appliances.

Mr. Jenkins said:—

In a paper recently communicated to the members of the
South Staffordshire and Warwickshire Institute of Mining
Engineers,* Prof. John Cadman drew attention to a possible
source of danger in connection with pneumataphors to which
an injector was fitted—namely, that it was possible, in case

of an unsuspected leak, to draw poisonous gases into the
apparatus, which might cause fatal results.

The writer was at once struck with the point raised by
Prof. Cadman, and in conjunction with his firm has endea-
voured to meet it by a simple contrivance. The object
sought to be attained is the elimination of the zone of
negative pressure, and to accomplish this it seemed a simple
matter to provide a reservoir of air at plus pressure which
would more than balance the tendency to negative pressure
on the suction side of the injector. Such a reservoir is
easily obtained by inserting a sort of envelope between the

* “Mine-rescue Appliances: A Danger Occurring in the
Use of Apparatus in which an Injector is Employed,”
Trans, Inst.M.E., 1912, vol. xliv., page 463.

Fig. 1.—Section of “Meco” Reducing Valve
and Injector.

PRESSURE GAUGE

.INJECTOR Q

SAFETY VALVE P

S NOZZLE

■I

It’Wl

put the regenerator on the back in a metal case, and thus
the heat was prevented from coming into contact with the
body of the wearer. Cooling pipes were also fitted, so that
the air on the inhalation side of the apparatus was kept
relatively cool; and even after two hours’ very severe
work, the temperature did not reach more than about
88 degs. Fahr., with an average percentage of carbon dioxide
of 01. This result was obtained in an independent test
taken by a committee of coalowners some six to eight
months ago. At the same test a non-injector apparatus was
found to average, after only hours’ work, 22 per cent, of
carbon dioxide, with a temperature of inspired air of as
much as 122 degs. Fahr. This is sufficient indication that
there are serious practical reasons for not reverting to the
old non-injector type of apparatus to overcome the difficul-
ties pointed out in Prof. Cadman’s paper.

As practically the whole of the interest centres round the
injector and its behaviour, a short description of the Meco
injector (fig. 1) will not be out of place.

Referring to fig. 1, the oxygen enters the reducing valve M,
at the same time indicating the pressure on the gauge.
This reducing-valve makes a reduction in the pressure to
about 5 atmospheres. This reduced pressure passes through
the nozzle N, which allows a uniform flow of 2 litres o^
oxygen per minute to pass into the circulating tubes of the
apparatus. The reducing-valve is so arranged that even
with only a pressure in the cylinders of 8 atmospheres, the
pressure of 5 atmospheres is still maintained behind the
injector nozzle. The nozzle chamber is fitted with a safety
valve P in order to release any excess pressure which might
be formed due to any failure on the part of the reducing-
valve. The oxygen, passing through nozzle N, has a
considerable velocity, and therefore a suction nozzle is
placed round the jet itself to utilise this velocity in
promoting circulation through the apparatus. The suction
nozzle projects slightly into a trumpet Q, and in this
trumpet a further mixture of the oxygen with a purified
exhaled air takes place, and passes through tubes R, 8, and T
on fig. 2 to the lungs of the wearer. The action of the
lungs of the wearer first of all causes suction on inhalation
and pressure on exhalation in the apparatus. This variation
of pressure reacts on the whole circulation, and consequently
when deep inhalation is taking place the air is drawn from
the whole of the inhalation side of the apparatus, thus

Fig. 2.—Section of Apparatus.

0

H

£

6imniiiiiiiiiiti!iiiiiiiiiiinii n

niUliilniimiii^iiiiiiiiiiHiiiu K

wearer, and to fit a reducing valve, so as to give a constant
supply of oxygen ; but difficulties were encountered due to
having the regenerative substance in a rubber bag, which
lay on the abdomen of the wearer. The heat of regeneration
due to the absorption of the carbon dioxide could not get
away, and consequently considerable difficulty was expe-
rienced in breathing after the apparatus had been in use for
just a little over half-an-hour. To obviate this defect the
metal regenerator was introduced (the so-called Shamrock
type), and in order to promote the circulation through the
apparatus without putting undue strain on the wearer’s
lungs, it was necessary to produce an artificial circulation,
not dependent upon the wearer. To obtain this circulation
an injector jet was introduced. The next change was to

causing a suction to occur in pipe K. Upon exhalation,
there is immediately a back-pressure on the inhalation side
of the apparatus, and pipe K is at once restored to a condition
of positive pressure (fig. 2).

In order to ascertain exactly what happens, it was decided
to test the pressures through the whole apparatus so as to
find where any negative pressure started. After much
difficulty a fairly satisfactory case was obtained, and a large
number of readings was taken from the apparatus when
worn by him, of which the curves shown in fig. 3 are an
average. Maximum and minimum pressures were recorded,
as shown by the undulations of the water-gauge. The test
was first of all taken on a standard type of Meco apparatus,
fitted with a slightly larger breathing-bag, to see if thL