Double-acting pumps

Druckpumpe/ doppeltwirkende Pumpe double-acting pump... 

Piston Pumps There are two ordinary types of piston pumps, simplex double-ac ting pumps and duplex double-acting pumps. 

Simplex Double-Acting Pumps These pumps may be direc t-acting (i.e., direct-connected to a steam cyhnder) or power-driven (through a crank and flywheel from the crosshead of a steam engine). 

FIG. 10-48 Double -acting steam-driven reciprocating pump. 

Dupl ex Double-Acting Pumps These pumps differ primarily from those of the simplex type in having two cyhnders whose operation is coordinated. They may be direct-acting, steam-driven, or power-driven with crank and flywheel. 

Occasionally phmger pumps are constructed with opposed cylinders and plungers connected by yokes and tie rods this arrangement, in effect, constitutes a double-acting unit. 

Figure 3-67. Duplex double-acting plunger pump, power driven. (Courtesy Worthington Corp.)...

For double acting pumps, single cylinder Q = (two times value for single acting) — 0.0204 d t,... 

For multiple cylinders, multiply the capacities just obtained by the number of cylinders. If the piston rod does not replace pumping volume as in some arrangements, the last term of the double acting capacity equation is omitted. 

Double-acting pumps are usually available with one or two pistons. 

A one-piston double-action pump is called a double-acting simplex (since there are older single-action steam and pneumatic driven simplex pumps). 

Figure 3-50. Schematic of valve operation of single and double-acting pumps [21].

Figure 3-51. Pressure-time curves for single-acting and double-acting pumps (one piston) [21].

Fig. 4.1-2. Principles of pressure generation A, Single-stage plunger pump B, Two-stage double-acting piston compressor (intercooling)...

Fig. 4.1-5. Time behaviour of the fluid flow. A Hydrodynamic pump/compressor. B Hydrostatic (double-acting) piston machine. Vm Average flow V(t) time volume flow...

Figure 9 is a schematic illustration of a double-acting PD piston pump. The volumetric capacity of this device per stroke of the piston is given by... 

FIGURE 9 Schematic illustration of double-acting piston pump. 

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