182
HYDRAULIC MACHINES—CENTRIFUGAL PUMPS.
[Class Y.
variable it may be; and that it does this, not for a singlestroke of the engine, or revolution of the wheel by whichthe machine is driven, but continuously, for a lengthenedperiod. The dynamometer was applied to a drum, astrap from which drove the pump. To ascertain thework yielded by the pump, the water, raised by it froma reservoir beneath the floor on which it stood, to a givenheight above it, was received into a reservoir on the floor,wherein was an aperture of a rectangular form throughwhich it could flow back into the reservoir, and whichcould be opened or closed to any extent by a slide. "Whenthe pump was set to work, the dimensions of the aperturewere so adjusted by means of the slide, that the water re-mained steadily at the same height in the reservoir. The
quantity of water which escaped by the aperture was thenobviously the same with that raised by the pump. Thedimensions of the aperture and the depth of the waterbeing known, the quantity of water which escaped couldbe calculated, and thus the water raised by the pump wasknown.
To ascertain the influence of the curved form of thevanes on the efficiency of the pump, straight vanes Mereapplied to a wheel of the same size, worked under thesame circumstances. The results are stated in the Table.
The pumps of Mr. Gwyxne (140, p. 1441) and Mr.Bessemer (421, p. 2-12), on which similar experimentswere made, the particulars of which are detailed in theTable, had straight vanes.
Carved Arms.
Number
of
Experiment.
Height
to which the Wateris raised.
Discharge perMinute.
Ratio
of Power toEffect.
Revolutionsof W'heet perMinute.
Remark?.
Feet.
Metres.
Gallons.
Litres.
1
S'2
2*59
2.100
9,540
0-583
828
All these experiments were made with
2
9-0
2-745
1,664
7,440
0-648
620
Poncelet and Morin’s dynamometer.
3
18-8
5-69
1,164
5,274
0-619
792
4
19*4
5-837
1,236
5,610
0-630
783
5
19*4
5-8 )7
1,248
5,676
0-650
800
6
20*2
7-97
432
1,962
0-398
843
7
27-6
8-235
631
3,030
0‘463
876
Straight Arms , inclined at 45°.
1
18-0
5-48
560
2,544
0-39S
694
2
18-0
5-43
736
3,343
0*434
690
Radial Arms.
1
18-0
5-48
369
1,674
0-2.32 |
624
2
18-0
5-48 j
474
2,148
0-243 i
1
720
Number
of
Experiment.
i
Height |
to which the Water ;is raised. j
Discharge perMinute.
Ratio
of Power toEffect.
Revolutionsof Wheel perMinute.
Remarks.
1
Feet.
13-8
Metres, i4-17 i
Gallons. Litres.290 1.320
0-19
675
Experiments made with dynamometer.
2
13-8
4-17 I
i
280 1,272
0-19
920
Experiments on Bessemer’s Centrifugal Pump . (Radial arms and conical sides. Experiments made with
McXaught’s Indicator.)
Number
of
Experiment.
Height
to which the Wateris raised.
Discharge perMinute.
Katio
of Power toEffect.
Revolutionsof Wheel perMinute.
Remarks.
i
Feet.
3-37
Metres.
1-027
Gallons.
832
Litres.
3,781
0-18
60
2
3-62
1-158
1,006
4,567
0-13
71
3
n-700
40-5
60
j No water thrown. The water just
4
3-427
1-100
896
4,067
( kept suspended up to the level of lip.
5
3-23
1-000
846
3,840
0-225
GO
Water Rams.
Honourable Mention is made of the following Ex-hibitors :—
F. Roe & Hanson, 70 Strand (462, p. 235. and Illus-trations). Hydraulic ram, for raising water to the topsof houses.
Easton, J. & Amos, C.E., Grove, ou hwark, part
Inventors and Manufacturers (408, p. 227). Improvedpatent hydraulic ram. The hydraulic ram* requires to be