Pumps and Hydraulics, Part 2 (of 2)

by N. Hawkins

For pumping sand or heavy material the speed of pump should be increased 25% more than for water.

Fig. 498.

The engraving Fig. [497] exhibits a steam-driven centrifugal pump of an approved design constructed by the Morris Machine Works.

This pump is directly connected to the engine and has a double suction. Pumps directly connected to engines are to be preferred over belt-driven pumps when conditions of elevation, etc., will allow, as they are self-contained, take up less space and are more economical.

The figure 498 shows a 20-inch hydraulic dredge, directly connected to a 450 horse-power triple-expansion engine. A hydraulic dredge consists mainly of a centrifugal pump with its driving engine and boiler, and hoisting machinery for handling suction pipe and boat; the pump in operation creates a strong suction flow in the suction pipe, sufficient to pick up the material and draw it into the pump, from which it is again delivered through the discharge pipe any distance to point of delivery, and can at same time be elevated to reasonable heights. Sand, mud, silt, etc., are readily picked up by the suction force only, but where material is packed it must first be agitated.

Table.

Diameter Discharge Opening	Capacity, Gallons per Minute	Elevations in Feet up to	Size Steam Cylinder		Size Steam Pipe, Inches	Size Exhaust Pipe, Inches
			Diameter	Stroke
2	120	25	3	3	3⁄4	1
21⁄2	180	25	3	3	3⁄4	1
3	260	25	3	3	3⁄4	1
4	470	25	4	4	3⁄4	1
5	735	25	5	5	1	11⁄4
6	1050	30	5	5	1	11⁄4
8	2000	30	8	8	11⁄2	21⁄2
10	3000	10	6	6	11⁄4	11⁄2
10#	3000	40	12	10	21⁄2	3
12	4200	20	9	9	2	3
12	4200	30	12	10	21⁄2	3
12#	4200	40	14	12	3	31⁄2
15	7000	30	14	14	3	4
15*	7000	22	12	10	21⁄2	3
18	10000	30	15	10	4	5
18*	10000	20	12	12		31⁄2
20	12000	20	14	14	3
* Low-Lift Pumps. # Special High-Lift Pumps.