224

THE COLLIERY GUARDIAN.

January 29, 1915.

resulting from charging. In the case of a lead cell
installation, the effect of acid spray on instrument cases,
etc., is very marked; but as the Sherwood lamps are of
the Wolf alkaline type, the risk of damage is not so
great. Special precautions have, moreover, been taken
to obviate risk of damage by the adoption of porcelain
covered switchgear, the use of stove enamelled instru-
ment cases, and by the elimination of lacquer work. For
the Langwith Colliery and several other recent installa-
tions, side switchgear has been fitted to the same
general design of stand. Side .switchgear is probably
the most desirable of all, for it is fairly well out of the
way of spray, each set of switch and regulating gear is
in direct line with the circuit it controls, and it is very
readily accessible. The only objection, if it can fairly be
raised as an objection, is that a lamp room for charging
stands with side switchgear needs to be about a yard
wider than if overhead or detached switchgear is used.

Charging Stand for Rescue Stations.

A modification of the pedestal form of charging stand
has been designed for installations not exceeding 50
lamps. This design is intended to reduce the over-all
cost of a small equipment, without omitting any of the
essentials for efficient maintenance. It consists of a
steel work bench, the underside of which is fitted with
lamp racks, while above the table there is provision for
charging 12 lead and 12 alkaline cells, or 24 of either
type. By adopting a back-to-back arrangement, the
capacity of such a board can be doubled. Between the
charging frames is a lock-up cupboard to hold hydro-
meters, test glasses, and other accessories. The switch -
panel above contains an ammeter, regulating resistance,
switch, and fuses for each 12-cell circuit, and a volt-
meter with testing fork of the kind already described,
which is common to both circuits. On the left of the
work bench is a powerful electro-magnetic unlocker
operated by a foot switch. The equipment is very suit-
able for rescue stations, combining as it does everything
necessary for the proper management of electric lamps.

In passing, it may be observed that any of the
charging stands described can be, and have, in fact,
been, adapted for charging any description and any size
of storage cell.

Lamp Racks.

The introduction of electric lamps has tended to bring
into general use the Continental type of lamp rack, the
distinguishing feature of which is that the lamps are
suspended from hooks instead of resting upon shelves as
in British flame lamp practice. The great advantage of
shelving in an electric lamp room, however, is that it
provides a resting place for the shells whilst the
batteries are on charge. Further, an arrangement of
charging stands and lamp racks on what may be
described as an alternating system has been put into
operation, and under this system it is a distinct advan-
tage to have each cell directly opposite the fittings
belonging to it. In general, it is the writer’s practice to
provide standard charging units with standard lamp rack
units of the same capacity. Separate number plates are
provided for each lamp place, and group number plates
for each complete rack.

Work Benches.

Work benches for electric lamp rooms are of much the
same character and dimensions as those used in flame
lamp rooms, but the different nature of the work of
handling and maintaining the lamps necessitates the
addition of services not hitherto associated with lamp
rooms. Storage cells and containing vessels require
periodical washing out, and thus an adequate supply of
water (preferably both hot and cold) is required, and
troughs must be provided, either as 'integral parts of
the work benches or as separate fitments. in ]arge
installations it is always better to put in glazed stone-
ware troughs of ample dimensions. Again, the differ-
ence between the flame lamp practice of dismantling,
cleaning, and reassembling, all more or less on the same
table, and of the necessity for carrying away storage
cells to be charged, calls for transportation facilities
which may be very simple or highly developed, accord-
ing to local circumstances. The work bench shown in
fig. 1 is fitted with a simple conveyor system, which
serves to transport the accumulators from one end of
the lamp room to the other. Such an arrangement is
adopted, as a variant to the floor trolley method, where
the cells are charged in a separate room. On the far or
wall side of the bench referred to, iron guide rails are
fixed, and a miniature trolley is hauled to and fro
between these rails by an endless wire rope, this in turn
being rotated by means of the hand wheels and shafting
shown in the drawing. The trolley or transport tray
(shown on a much larger scale than that of the table) is
made to carry 40 cells, each set of 20 resting on a detach-
able tray provided with carrying handles at each end.
The details of this transport carriage are shown in fig. 2.
In more elaborate installations a small geared motor
drive is substituted, which can be started and stopped
by press-button switches arranged at suitable intervals
along the front of the work bench. In the Sherwood
lamp room a simple rope conveyor is used, while at
other collieries floor trolleys are made to serve the same
purpose.

The work bench itself is built of steel framing, with
a sheet iron top and raised ledge all round. Enamelled
iron washing tanks are fitted as shown, together with
lock-up steel tool drawers.

Cleaning Machines.

More or less, the type of cleaning machine used for
cleaning flame lamp gauzes and lamp glasses is suitable
for the cleaning of electric lamps. It should be borne
in mind that the shells of electric lamps are often wet
from acid, and are consequently troublesome to clean on
ordinary machines. Wet parts of lamps are best
handled at the washing sink and kept away from the
cleaning brushes and buffing discs used for cleaning
glasses, lamp cages, and so forth. An item in the main-

tenance of electric lamps which will be appreciated more
as time goes on is that of renewing lamp cases.

A typical example of a modern cleaning machine,
motor-driven, is shown in figs. 3 and 4. This cleaner
combines every movement which the work requires,
with a vacuum exhaust system to carry away all the
dust removed from the lamp parts during cleaning. The
motor is direct-coupled to a driving shaft carrying a fan,
the casing and suction hoods attached thereto being
arranged as shown in the figures. The moving parts
are all securely fenced, and there seems to be no pos-
sibility of any accident occurring to a workman using
the machine.

A simplified way of dealing with the cleaning problem
is to employ small motors having extended spindles, to
which suitable brushes are fitted, or a belt-driven cleaner
may be used.

In passing, brief reference may be made to the above-
mentioned table. It has been standardised for the use
of small lamp rooms, and is provided with a white
enamelled washing trough and lock-up tool drawer. Pro-
vision is also made for attaching to it a cleaning motor,
and electro-magnetic unlocker, and other accessories.
As the writer has developed a system of charging both
lead and alkaline cells without taking them out of their
containing shells, it became apparent that means must
be found of cleaning quickly the bottoms of the shells,
in order to prevent the rapid accumulation of dirt on the
glass trays. For this purpose table brushes—miniature

Front elevation.

lust Hood

Fan

Exhaust Outlet

Figs. 3 and 4.—Motor Cleaner with Vacuum Dust Exhaust.

End view,

S- TC

Electro magnet for lamp-cabin installations

2

To bolFcn any wt "tench

Rittrn

Fig. 5.—Electro-magnetic Unlockers.

door mats, as it were—have been made, and these are
screwed down to the work benches next to the lamp
receiving windows.

Unlocking Machines.

Electric lamps are locked either by lead rivets, as in
the earlier flame lamp practice, or they are provided
with plunger locks which can only be lifted magnetically
against the force of the spring which normally holds the
plunger down. The writer’s standard design is made
either for fitting to a bench or as a self-contained
pedestal. The switch used with these unlockers is of
special design—apart from the fact of its being arranged
to work by the foot SO’ as to leave both hands free.
When the foot lever is depressed, the double pool knife
edge switch is closed, and simultaneously a hardened
steel detent engages a suitably disposed pawl, and so
holds the switch contacts “ on.” When the foot lever
is released, the circuit remains closed, and does not open
until, after a momentary time interval, a trip bar on the
rocking shaft knocks off the detent. Both the pedestal
and bench forms of unlocker are illustrated in fig. 5.

(To be continued.)

A.t the general meeting of the graduate section of the
North-east Coast Institution of Engineers and Shipbuilders,
to be held in the institution library to-morrow (Saturday),
at 7.15 p.m., a lecture on “ Turbines ” will be delivered by
Mr. Gerald Stoney, F.R.S.

MIDLAND INSTITUTE OF MINING, CIVIL
AND MECHANICAL ENGINEERS.

SOME POWER COST COMPARISONS.

A general meeting of the members of the Midland
Institute of Mining, Civil and Mechanical Engineers
was held at the Danum Hotel, Doncaster, on Saturday,
January 23, Col. T. W. H. Mitchell being in the chair,
in the absence of the president, Mr. Walter Hargreaves,
through indisposition.

It was announced that the following new member
and associates had been proposed and approved by the
council :—Member : Mr. William Armley Wooler, New
Lodge, Wortley, near Sheffield. Associate members :
Mr. Fred Chambers, Wharncliffe-chambers, Bank-street,
Sheffield; Mr. Albert Frost, 3, Howard-street,
Sheffield.

Power Costs.

Mr. William B. Woodhouse then read a paper on
“ Power Costs,” an abstract of which appears on
p. 226.

In the course of the discussion on the paper, the
Chairman said he felt sure that in the coal trade they
would benefit very much, if they had time, or if their

managers had time, to devote to the more theoretical
working out of the cost and efficiency of their
machinery. Unfortunately, the Legislature did not give
the managers time to do their own work at present,
except sign their names.

Mr. G. Blake Walker thought that all of them would
be struck by one point perhaps more than any other in
Mr. Woodhouse's paper, and that was the low load
factor, which he mentioned as being characteristic of
colliery loads. Of course, the load factor depended on
the nature of the work and its regularity. It occurred
to him that some figures with regard to their gas plant
at Wharncliffe Silkstone might be interesting, because
they had a load factor there of over 60 per cent., and the
reason was that night and day they were working their
gas engines, sometimes up to their fullest capacity, or,
at any rate, to something very considerably over half
their capacity, and that was going on throughout the 24
hours. Mr. Woodhouse had confined himself to the
generation of power by steam engines or turbines, but
in the case of collieries which had by-product coke ovens,
the question of generating power by gas was also
deserving of attention. The cost should be estimated
as fairly as possible on units of similar power, so that a
comparison between gas and steam may be arrived at.
The main items in each case were :—(1) Cost of steam
or gas; (2) cost of running gas engines or steam tur-