January 23, 1914..

THE COLLIERY GUARDIAN.

203

free as possible. The apparatus is very likely to be
needed for penetrating along roads wrecked by an
explosion, or injured by fire, water, or steam, or along
old roads. Anyone who is familiar with the conditions
often met with on such roads will realise how important
it is to see and avoid loose timber and stone projecting
from the roof. It may take very little to bring down a
mass of loose stone from the roof. Apart from this
danger, a man who cannot see properly is very likely to
injure either himself or his apparatus by violent contact
with the roof or sides. A helmet or. full mask greatly
limits the vision forwards and upwards when the head
is bent downwards, as is usually the case in a mine road.
The roof may not be visible at all. Hence helmets are
a great disadvantage, and, indeed, seem to me far from
safe under the conditions just referred to. With a
mouthpiece or half-mask, vision is left free. A half-
mask is more comfortable than a mouthpiece, and
permits the wearer to speak distinctly ; but the danger
of leakage far outweighs this advantage. With a good
and properly secured mouthpiece a tight joint is
obtained, and men soon accustom themselves to a
mouthpiece, and learn to make themselves understood
through it.

The same underground conditions as make a helmet
risky seem also to render it undesirable that any part
of a rescue apparatus should project from the head or
shoulders of the wearer. The “ Proto ” apparatus has a
distinct advantage over all the others in this respect, for
the head and shoulders are quite free, so that there is
less risk from an unsafe roof, and no risk of injuring
the apparatus against the roof.

In respect to freedom of movement of the head, the
“Weg” apparatus seems preferable to all the others.
It and the “Proto” are also more comfortably balanced
than the “ Draeger ” or “ Meco.”

All the forms of apparatus with oxygen cylinders can
be quickly brought into use or put temporarily out of
use when required. In this respect they are superior to
the liquid air apparatus, which takes some time to
charge, and when once charged cannot be prevented from
continuously wasting the liquid air. For charging or
re-charging with liquid air underground, cumbrous
vessels have also to be conveyed to the place and
properly manipulated. The reserve stock of liquid air is
also constantly wasting, and must be frequently renewed,
whereas oxygen in a cylinder keeps indefinitely. If a
purifier could be dispensed with, there would be some
counter-balancing convenience on the side of liquid air,
but to dispense with the purifier a very unwieldy charge
of liquid air would be needed. It is difficult to see how
the liquid air apparatus can compare with the others as
regards convenience.

In the “Draeger” apparatus the purifier cartridge
can be changed or placed in position more rapidly than
in any other apparatus, and the operation can be safely
performed with the apparatus in use, which is a con-
siderable advantage.

Before using any apparatus it is most essential to
test it for tightness and for the proper working of
essential parts. Tho “ Proto ” can easily be tested with
positive or negative pressure. The “Draeger” and
“ Meco,” with mouthpiece, can similarly be tested with
negative pressure, but the automatic blow-off valve
causes difficulty with positive pressure. With the half-
mask and helmet forms there is much difficulty in
testing satisfactorily for tightness. With the“ Draeger,”
“Meco,” and “Proto” it is also desirable to test the
delivery of the oxygen cylinder. With the “Draeger”
and “ Meco ” the air circulation must also be tested.
These tests can be quickly performed with the float air-
meter referred to above. In our experience the float
air-meter is very reliable. The gauge should also be
tested occasionally. It is specially important to see
that the gauge does not indicate too high when the
pressure is near zero. With the liquid air apparatus it
seems desirable to know how much liquid air actually
reaches the container in charging. For this weighing
is necessary.

My experience of the actual working of the different
apparatus underground and at experimental galleries, is
not sufficient to enable me to say how much difficulty is
found in keeping each apparatus fit for use and applying
the necessary tests, or to what extent proper precautions
are actually taken.

Liability to Mechanical Injury or Interference during
Use.—A mechanical injury to a rescue apparatus might
easily cause a fatal accident. Thus a joint loosened, or
a tube or purifier penetrated or torn by a blow might
easily cause dangerous leakage. Any part of the
apparatus carried on the shoulders is specially liable
to injury in a coalmine, and an injury at this part is
the more dangerous since the wearer cannot see the
injured place. In the “ Meco ” apparatus the parts
resting on the shoulders would be readily£injured,

and have no protection. The corresponding parts of
the “ Draeger ” apparatus are partly protected by
metal hoops, and are of somewhat stronger construc-
tion. It seems to me that in both apparatus, but
particularly the “ Meco,” the back parts, with their
rigid metal joints and thin-walled metal purifiers,
must be a source of anxiety in the absence of effective
protection from injury. The danger from a small
leak is, however, much less with positive pressure
in the purifier, as in the newer apparatus. In the
“Weg” the construction is much stronger, and a
leather cover protects the purifier. With the “ Proto ”
the shoulders are free, and nothing behind is readily
liable to injury, as only the cylinders are carried behind.
There is a vulnerable point at the side, however. A
“ Proto ” apparatus, which was not known to have
received any blow or injury, was left hanging in the
apparatus room with the oxygen tube touching the wall,
and bearing some considerable pressure. On the next
examination it was found that the brass end on the
oxygen tube had snapped across between the points at
which it is attached to the rubber tube and the valve
attached to the oxygen cylinder. Such a breakage in a
poisonous atmosphere would be very dangerous. The
part in question should be much stronger. It is in a
somewhat exposed position on the wearer’s side, and
might easily receive a blow against stone or timber. In
another apparatus it was easily broken by a blow from
a light hammer.

The breathing bags are well protected by aprons or
stout covers in all the apparatus. The recent fatal
accident to Capt. Hamsay, and experience at Norton
Colliery, as referred to in the report for 1912 of Mr. H.
Johnstone, H.M. inspector of mines, having shown the
absolute necessity of guarding against the main valve
of the oxygen cylinders becoming accidentally turned
off by contact with the sides or floor. Arrangements
for preventing this accident are now provided by
makers, and should be used in all apparatus.

Liability to Effects of Heat and Smoke.—The “ Proto ”
apparatus in its ordinary form is defective owing to the
fact that the inspired air is liable to become too hot to
breathe, except with much discomfort, after an hour or
more of work in a warm atmosphere. In very hot and
moist air, at gob fires, &c., it will probably be impossible
in any case for men to work for long while wearing
self-contained apparatus, and the “ Proto ” may give
cooler and drier air for a time than some of the other
apparatus with oxygen cylinders, since the purifier takes
longer to heat up to the surrounding temperature. In
fairly dry air, at temperatures of 90 degs. or more, the
defect in the “ Proto ” will be serious, and will prevent
work which might be possible with other apparatus. A
cooler submitted for trial by the makers was effective,
but was too liable to injury to be used safely. The
“ Aerophor ” is undoubtedly the most comfortable
apparatus for work in hot air, and but for its defects in
other respects we should have tried it in a hot place.

The whole question of the possibilities of work in hot
air with self-contained apparatus or smoke helmets, or
without apparatus, requires further investigation.

As regards smoke, the eyes are, of course, left unpro-
tected when a mouthpiece or half mask is used. Goggles
seem to be usually a sufficient protection for work in
mines. The helmet of the “ Draeger” or “ Meco ” gives
better protection, though even this is not sufficient in
dense fumes, as mentioned above. The mask of the fire
brigade pattern of “ Proto ” gives perfect protection, but
for ordinary mine work in moderately smoky places it
limits vision too much.

Resistance to Breathing.—This, of course, limits the
capacity for doing work, but it was only in the case of
the “ Weg ” and “ Aerophor ” apparatus that we
noticed resistance which would cause inconvenience in
such work as might be required in a mine. Undue
resistance can easily be got rid of.

Tightness of the Apparatus.—This is a matter of vital
importance in poisonous air, and of considerable
importance as regards risks of oxygen shortage in
atmospheres of firedamp or blackdamp. The “ Draeger ”
and “ Meco ” helmets and the “ Aerophor ” half-mask
were all leaky, and would be unsafe in poisonous air.
The “Weg” half-mask needed great precautions to
prevent leakage, and apparently it leaked inwards badly
in several experiments where these precautions were not
taken. An “ Aerophor ” blow-off valve also leaked
inwards badly, and we have occasionally noticed other
automatic blow-off valves leaking either inwards or
outwards when they ought to have been tight. A blow-
off valve, such as that in the “ Proto,” which does not
open automatically, is probably safer, though less
convenient.

It seems probable that a number of fatal accidents
with rescue apparatus have been caused, directly or
indirectly, by leakage. Every man who uses a rescue

apparatus ought to test the whole of it for leakage
before he goes into a dangerous atmosphere, and ought
to know how to make the test in a thorough manner.

Liability to Defects in Oxygen Supply.—Provided
there is no leakage, a supply at the rate of 2 litres a
minute suffices for ordinary exertions up to that of
walking at 3| to 4 miles an hour. With great exertion,
such as that of ascending an incline at a moderate speed,
more than 2 litres might be consumed, however, and
this ought to be well understood. With none of the
apparatus, provided they were used according to the
makers’ directions, and with no greater exertion than
walking at 31 to 4 miles an hour, did we abserve any
symptoms due to want of oxygen. In the “Weg”
apparatus, however, the oxygen supply sometimes ran
down very quickly, owing to leakage outwards through
the blow-off valve and half-mask. In the “ Aerophor ”
the wearer was once or twice stopped through the air
in the bag being blown off through the blow-off valve,
and the same thing occurred once with the “ Draeger”
through the blow-off valve sticking in an open position.
With the “ Aerophor” it would probably be necessary
to test each apparatus separately, so as to make sure
that the charge would last for two hours. The rate of
evaporation of the liquid air must depend on the degree
of heat-insulation of the container, and will probably
vary more or less in different containers. As there is
no means by which the wearer can ascertain how much
liquid air is left in the container, it is necessary to make
sure that the charge will last ovei’ two hours.

Liability to Defects in Removal of CO 2.—With ordinary
walking exertion the helmets of the “ Draeger ” or
“Meco” apparatus become so charged with CO2 as to
cause great distress in breathing, or even rapid disable-
ment if the apparatus is not working very well. The
current driven by the injector through the purifier is
quite insufficient to wash out the CO2 in the helmet.
With the “ Draeger ” or “Meco” mouthpiece the dis-
advantage of the limited air circulation is far less
marked, and if the injector is working well there is, with
ordinary exertion, no distress from CO2. The injector
is, however, very liable to get more or less out of order,
and is certainly a source of serious complication and
weakness. In the “ Proto ” the design is such that
there is no need for an injector, and this is, to my mind,
a great advantage, although it is partly neutralised by
the fact that the caustic soda in the breathing bag may
have to be shaken up every few minutes. The “ Proto, ’
particularly in the fire brigade form, permits of greater
exertion than any of the other apparatus. In the
“ Weg,” also, there is no injector, but the resistance in
the latter apparatus is certainly disadvantageous.

In the “ Draeger ” and “ Aerophor ” the purifiers
failed in lasting power, and such failure might have
serious consequences underground. The large-sized
“ Meco ” purifier, and the “ Proto ” and “ Weg ” purifiers,
were sufficient.

It is quite evident from the results of our experiments
that a number of serious and more or less dangerous
defects exist in rescue apparatus at present in use in
this country, and in the manner of using them. The
sooner these defects are recognised, the sooner will they
be remedied, or adequate means be taken to guard
against harm resulting from them.

At a meeting of the Cleveland Institution of Engineers,
held at Middlesbrough on Monday evening, Mr. D.
Neustadter, of London, gave a paper on “Application of
Clean Blastfurnace Gas?’ Mr. Edward Crowe, the
president, occupied the chair. Mr. Neustadter said blast-
furnace gas was calling more and more for their attention,
which was only natural, as this gas was an always present
by-product, and appeared in very large quantities. Cleaned
blastfurnace gas had been applied in some ironworks for a
considerable time to other purposes besides engines, boilers
and stoves. They saw lately blastfurnace gas introduced
for heating soaking pits, mixers, melting furnaces, push
furnaces, coke ovens, to an increased extent in foundries,
for briquetting iron ores, and further in cement plants and
other allied and attached manufacturing processes. It was
expected by one large and newly equipped iron and steel
works in Luxemburg, which, however, was not yet fully
working, that by means of highly cleansed blastfurnace
gas, all requirements on power and heat for the ironworks
and the very large rolling mills would be ultimately covered
and neither solid coal nor producer gas nor coke oven gas
would need to be employed. Extensive use was now made
of blastfurnace gas mixed with coke oven gas for open
hearth furnaces, which had proved very successful. Profit-
able use of blastfurnace gas was also made now for firing
coke ovens, through which the more valuable coke oven gas
is saved for other purposes such as lighting of towns, &c.
High cleanliness of the gas was now obtained cheaply and
conveniently by means of dry filtering, the cost of which,
including depreciation and interest, were in no case more
than one-thirtieth of a penny per 1,000 cubic feet of dry gag
cleaned.