Reciprocating Power Pumps

6.0 Scope

This Standard applies to reciprocating power pumps. It includes types and nomenclature; definitions; design and application; and installation, operation and maintenance.

6.1 Types and nomenclature

A reciprocating power pump is one driven by power from an outside source applied to the crankshaft of the pump. It consists of a liquid end and a power end.

6.1.1 Horizontal pump

The axial centerline of the cylinder is horizontal (see Figure 6.2).

6.1.2 Vertical pump

The axial centerline of the cylinder is vertical (see Figure 6.3).

6.1.3 Piston pump

The liquid end contains pistons (see Figure 6.4).

6.1.4 Plunger pump

The liquid end contains plungers (see Figures 6.2, 6.3 and 6.5).

6.1.5 Single-acting pump

Liquid is discharged only during the forward stroke of the plunger or piston, that is, during one half of the revolution of the crankshaft (see Figures 6.2 and 6.3).

6.1.6 Double-acting pump

Liquid is discharged during both the forward and return strokes of the piston or pair of opposed plungers. That is, discharge takes place during the entire revolution of the crankshaft (see Figures 6.4 and 6.5).

6.1.7 Simplex pump

Contains one piston or one plunger or a pair of opposed plungers driven by one connecting rod (see Figures 6.4 and 6.5).

6.1.8 Duplex pump

Contains two pistons or two plungers or two pair of opposed plungers driven by two connecting rods.

6.1.9 Multiplex pump

Contains more than two pistons or two single-acting or opposed plungers.

Number of Power Crossheads	Type pump
1	Simplex
2	Duplex
3	Triplex
5	Quintuplex
7	Septuplex
9	Nonuplex

6.1.10 Description of components

The nomenclature and definitions in these standards were prepared to provide a means for identifying the various pump components included in these Standards and also to serve as a common language for all who deal with this type of equipment. The following definitions and drawings illustrate typical construction of reciprocating power pump components but do not necessarily represent recommended designs. Variations in design may exist without violating the intent of these Standards.

6.1.10.1 Right and left hand shaft extension of power pumps

“Right” or “left hand” designates the side of the power pinion shaft extends. (It does not designate in which direction the shaft rotates.)

Horizontal power pumps are termed right hand or left hand as viewed when standing behind the power end with the liquid end being the most distant part. A left hand pump has the shaft extending out of the left side of the power end. A right hand pump has the shaft extending out of the right side of the power end (see Figure 6.6).

Vertical power pumps are termed right hand or left hand pumps as viewed when standing at and facing the suction manifold of the pump. A left hand pump has the shaft extending out of the left side of the power end. A right hand pump has the shaft extending out of the right side of the power end (see Figure 6.7).

6.1.11 Liquid end

That portion of the pump which handles the liquid. It consists of a liquid cylinder, valves and other components.

6.1.11.1 Liquid end parts

The following sections describe major liquid end components which are shown in Figures 6.24 through 6.27. A listing by part name is shown in Table 6.1, which also shows the standard abbreviation.

6.1.11.2 Liquid cylinder

A chamber(s) in which the motion of the plunger(s) or piston(s) is imparted to the liquid. The cylinder can be made integral with a suction and discharge manifold or can be made with separate manifolds (see Figure 6.8).

6.1.11.3 Cylinder liner

A replaceable liner which is placed in the cylinder of a piston pump. The piston reciprocates within the liner (see Figures 6.27 and 6.28).

6.1.11.4 Manifolds

A suction manifold is a chamber which accepts liquid from the suction port(s) and distributes it to the suction valves (see Figure 6.9).

A discharge manifold is a chamber which accepts liquid from the individual discharge valves and directs it to the discharge port(s) (see Figure 6.9).

6.1.11.5 Valve chest cover

A cover for the valves within the cylinder (see Figure 6.28).

6.1.11.6 Valve plate (valve deck)

A plate that contains the suction or discharge valves (see Figure 6.28).

6.1.11.7 Piston

A cylindrical body which is attachable to a rod and is capable of exerting pressure upon a liquid within the liquid cylinder. A piston usually has grooves for containing rings which seal against the cylinder or cylinder liner.end

A piston in a reciprocating pump can be double-acting. The pistons in Figures 6.10 and 6.11 have followers which retain the packing rings.

6.1.11.8 Plunger

A smooth rod which is attachable to a crosshead and is capable of exerting pressure upon a liquid within the liquid cylinder (see Figure 6.15). Sealing rings for a plunger are stationary, the plunger sliding within the rings.

A plunger is single-acting, requiring a double-acting pump to have two plungers on each crosshead axis (see Figure 6.6).

6.1.11.9 Stuffing box

A cylindrical cavity through which the plunger or piston rod reciprocates and in which liquid leakage is controlled by means of packing (see Figure 6.16).

A follower ring and throat bushing are used to guide the plunger or rod as it reciprocates. The throat bushing and follower ring contain the packing within the stuffing box.

6.1.11.10 Packing

A material used to provide a seal around the plunger, piston rod, or piston (see Figure 6.17).

6.1.11.11 Gland

A part which retains the packing in the stuffing box (see Figure 6.18).

6.1.11.12 Lantern ring (seal cage)

A ring located in the stuffing box to provide space for the introduction of a lubricant or a barrier liquid (see Figure 6.19).

6.1.11.13 Valve assembly

Usually consists of a seat, valve, spring and spring retainer. It allows liquid to enter and leave each pumping chamber of the cylinder. Each pumping chamber has one or more suction and discharge valve(s) (see Figures 6.20 through 6.23).

6.1.11.14 Upper crosshead

Used in vertical plunger pumps to transmit the reciprocating motion of the side rod to the plunger (see Figure 6.24).

6.1.12 Power end

That portion of the pump in which the rotating motion of the crankshaft is converted to a reciprocating motion through connecting rods and crossheads (see Figures 6.39, 6.40, 6.41).

6.1.12.1 Power end parts

The following sections describe major power frame components which are shown in Figures 6.38 through 6.40. A listing by part name is shown in Table 6.2 which also shows the standard abbreviation.

6.1.12.2 Power frame

That portion of the power end which contains the crankshaft, connecting rods, crosshead and bearings used to transmit power and motion to the liquid end. It may consist of one or two pieces (if two, there is one upper and one lower half) (see Figure 6.29).

6.1.12.3 Crankshaft

The stepped shaft which transmits power and motion to the connecting rods. Main bearings and connecting rods are fitted on this member (see Figure 6.30).

6.1.12.4 Main bearing

The bearing which supports the crankshaft. Main crankshaft bearings may be sleeve or rolling element type, mounted at each end of the shaft or located elsewhere to provide proper support. These bearings absorb the liquid and inertia loads that are developed by the plunger as it displaces the liquid (see Figures 6.31 and 6.32).

6.1.12.5 Connecting rod

Articulates the motion of the crankshaft to the crosshead. Power is transmitted through compression and/ or tension (see Figure 6.33).

6.1.12.6 Crankpin bearing

Transmits the oscillating reciprocating load transmitted by the connecting rod to the crankshaft (see Figure 6.34).

6.1.12.7 Power crosshead

Creates a linear reciprocating motion derived from the crankpin rotary motion through the connecting rod.

The reciprocating motion of the crosshead is applied to the plunger or piston via the side rods or crosshead extension (see Figure 6.35).

6.1.12.8 Wrist pin

Connects the connecting rod to the crosshead (see Figure 6.36).

6.1.12.9 Wrist pin bearing

Transmits the reciprocating load of the crosshead into the connecting rod (see Figure 6.36).

6.1.12.10 Crosshead extension (plunger extension)

Connects the crosshead to the plunger (see Figure 6.37).

6.1.12.11 Frame extension

Connects the liquid end to the power frame when the liquid end is not bolted directly to the frame. A horizontal extension is sometimes called a cradle (see Figure 6.38).

 

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