March 20, 1913.

THE COLLIERY GUARDIAN.

595

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Fig. 3.—Humphrey Pump : Combustion Chamber for the 40,000,000
GALLONS PER DAY PUMPS AT ChINGFOBD, PARTLY FITTED
with Exhaust Belt and Gas Belt.

ARRANGEMENT OF HUMPHREY PUMP

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Fig 4.

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Fig. 5.—Humphrey Pump : One of Two Suction Valve Box Sections for the
20,000,000 gallons per day Pump at Chingford. Valve Seatings
and Valves Partly Fitted.









resembling an ordinary engine indicator, which closes
the electric ignition circuit at the point of maximum
compression, and an ordinary small battery, trembler
coil, and sparking plug, as used in motor car work, are
employed.

It should be noticed that the only moving parts,

namely, the valves, open and shut under slight changes
! in pressure, and are all on their seats when explosion
occurs ; consequently there is no shock, and the pump
works quietly and smoothly.

In starting the pump for the first time, compressed
air is allowed to flow into the combustion chamber until

the volume of air introduced is rather larger than the
usual charge. The exhaust valve is then suddenly
1 opened by means of a hand lever, and the escape of the
compressed air permits a movement of the water column
which gives the cushion and suction strokes, and so
draws in a fresh combustible charge, which, on ignition,
starts the pump working regularly. If the pump is
stopped when in regular work it always stops with a
fresh charge of gas and air in the combustion chamber,
and then the re-starting of the pump is simply effected
; by switching on the ignition current. The pump can
. therefore be started and stopped from a switchboard.
1 At Chingford the large pumps are started by forcing
gas and air into the combustion chamber and then firing
the charge by the ignition circuit.

The Humphrey Pump at Chingford.—From the above
description of the mode of working of the internal
I combustion water pump in its simple form, it is easy to
1 pass to the form of pump installed at Chingford, which
| in fact differs in no respect in principle, and but little in
essential detail, from the simple type. The conditions
to be met are a total output of 180,000,000 gallons per
24 hours, and a lift of 25 to 30 feet. For this purpose
five pumps have been installed, four having each a
capacity of 40,000,000 gallons per day and one of
20,000,000 gallons per day. These pumps are arranged
as shown diagrammatically in fig. 4, which shows a
combustion chamber fitted with a gas belt for supplying
the producer gas, and an exhaust belt for collecting the
burnt products. Below the combustion chamber are
two water-inlet valve-boxes of cast iron, bolted to a cast
steel taper bend, connecting with the horizontal steel
play pipe. At the further end of the play pipe is a
cast iron bend supporting a conical water tower, with
an open top. This tower provides for the fluctuating
levels of water due to the to-and-fro movements of the
column of water in the play pipe, and maintains a
continuous discharge to the high level reservoir through
the discharge main shown on the extreme right of the
drawing. Various parts of the pumps are shown in the
photographs (figs. 3, 4, and 5), which are sufficiently
explained in the inscriptions. There is one difference in
detail from the simple form shown in fig. 1. In place of
the large single valves for admission and exhaust, a
number of smaller valves are used in the Chingford
pumps.

The dimensions of the pumps are as follow:—The
pump cylinders of the larger units are 7 ft. in diameter,
and of the smaller pump 5 ft. in diameter. The bend
which connects the bottom of the suction-box to the
play-pipe is a steel casting, with a bore tapering from
7 ft. to 6 ft. It serves to anchor the pump chamber to
the foundation against the up-lift due to the fact that
the full pressure of the explosion does not reach the
bottom of the bend, a part being absorbed in the mass
acceleration of the intervening fluid. The castings
constituting the combustion chamber, valve box and
bend weigh about 64 tons. The horizontal pipes are
6 ft. in diameter throughout. The water tower is 15 ft.
in diameter at the top, which is 9 ft. above the highest
water level of the reservoir, and »8 ft. from the bottom
of the tower. On each explosion 12 to 15 tons of water
are abstracted from the river and delivered into the
reservoir against a 30 ft. head.

The valves are simple flap-valves. It had been
originally intended to use Gutermuth valves, but these
were found to present certain difficulties. The valves
and valve seats are of gun metal.

The gas plant is Dowson producers, for anthracite
coal, of which one is capable of gasifying 138 lb. of coal
an hour, and three others are capable of gasifying
370 lb. each. The usual cooling plant, scrubbers and
producer-house are provided, and there is an electric
bucket elevator for lifting the coal to the stoking
platform.

The pumps are under perfect control, and can be
started or stopped instantaneously by means of a switch
on the electric ignition circuit. The pumps are placed
in five suction chambers, 32 ft. long by 18 ft. wide, upon
concrete foundations. The water reaches these chambers
from a sump measuring 134ft. by 12 ft. by 12 ft., the
supply being regulated by automatic float valves,
whereby it is maintained within fixed levels.

The guaranteed cost of pumping is 0’0196d. per
1,000 gallons delivered into the reservoir, with coal at
22s. per ton delivered; but the actual cost is expected
to be about 0 016d.

The Chingford pumps were designed by the inventor,
Mr. H. A. Humphrey, and the staff of the Pump and
Power Company Limited, of 38, Victoria-street, West-
minster. The contractors are Messrs. Siemens Brothers
Dynamo Works Limited, at whose works at Stafford
the parts were made. The contract price for the pumps,
producers, &e., is £19,388.

Large as these pumps are, they do not by any means