There are four single acting outside packed plungers, which work into the ends of the water cylinders, the latter having central partitions; each individual valve has its own cover or bonnet. The arrangement of compound steam cylinders is shown. The water valves are easily accessible, and are contained in small chambers, capable of resisting very heavy pressures. The general arrangement shown in the engraving is subject to numerous alterations, according to various requirements, but the general characteristic of four outside packed plungers is in all cases preserved.

Fig. 306.

SPECIAL DUPLEX PUMP.
(Outside packed Plunger Pattern for High Pressure.)

Table.

Steam
Cylinders.
Water
Plungers.
Stroke.Capacity in Gallons,
per Stroke
each Plunger.
Strokes per
Minute,
each
Plunger.
Ins.Ins.Ins.
165121.0250 to 100
166121.4750 „ 100
167101.6650 „ 100
167183.0040 „ 80
168122.6150 „ 100
168183.9140 „ 80
169123.3050 „ 100
18127122.0050 „ 100
1812712122.3050 „ 100
18128183.9140 „ 80
18129184.9540 „ 80
181210124.0850 „ 100
181210186.1240 „ 80
208122.6150 „ 100
208183.9140 „ 80
209123.3050 „ 100
209184.9540 „ 80
2010124.0850 „ 100
2010186.1240 „ 80
Steam
Cylinders.
Water
Plungers.
Stroke.Capacity of
Both
Cylinders, in
Gallons,
per Minute.
Steam Pipe.
Ins.Ins.Ins.Ins.
16512102 to 204212
16612147 „ 294212
16710166 „ 332212
16718240 „ 480212
16812261 „ 522212
16818312 „ 625212
16912330 „ 660212
1812712200 „ 4003
181271212230 „ 4603
1812818312 „ 6253
1812918396 „ 7023
18121012408 „ 8163
18121018490 „ 9803
20812261 „ 5224
20818312 „ 6254
20912330 „ 6604
20918396 „ 7924
201012408 „ 8164
201018490 „ 9804
Steam
Cylinders.
Water
Plungers.
Stroke.Exhaust Pipe.Suction Pipe.
Ins.Ins.Ins.Ins.Ins.
1651234
1661235
1671036
1671837
1681237
1681838
1691238
18127123126
1812712123126
18128183128
18129183128
1812101231210
1812101831210
2081257
2081858
2091258
2091858
201012510
201018510
Steam
Cylinders.
Water
Plungers.
Stroke.Discharge Pipe.Water Press.
Pump End will
stand, in lbs., per
square inch.
Ins.Ins.Ins.Ins.
165123450
166124450
167105300
167186450
168126300
168187450
169127250
18127125250
1812712125300
18128187450
18129187250
181210128250
181210188250
208126450
208187450
209127250
209187250
2010128250
2010188250

A test of the superiority of this method of moving, and controlling long columns of fluids under extreme heavy pressures was made at the time of the introduction of long pipe lines for conveying oil from the wells to the seaboard.

Note.—After trying various kinds of pumps for forcing the oil through these long pipes, and after having a succession of disasters in the way of burst pipes, and leaking joints, it was decided to test the efficiency of the direct-acting duplex steam pump. These pumps were placed in the various stations along the pipe lines, and after a continued service of many years, have shown their perfect adaptation to that exceptionally hard service. These pumps convey the oil over mountains where at times the coupled lines have been over one hundred miles long between the pumps, and where the pressure on the plunger of the pump sometimes rises to 1,500 lbs. per square inch.