What does the '1.75 inch OD' in the name mean?

1.75 inch OD is the outer diameter of the piston cup; the depth is about 1.00 in.

What is the cross-reference for this piston cup?

It is an aftermarket replacement for FMC Bean part 5259944; the brand and part number are listed only for identification and cross-reference, not to claim factory manufacture.

5259944 Piston Cup 1.75 Inch OD

5259944 Piston Cup 1.75 Inch OD — Piston Cup aftermarket replacement part

The 5259944 is a 1.75-inch OD piston cup for reciprocating pumps. As a piston cup, it is the flexible sealing element fitted to the piston in the fluid end, maintaining the seal against the cylinder liner bore as the piston reciprocates; wear here directly affects volumetric efficiency, making it a routine wear part. It is an aftermarket replacement for FMC Bean part 5259944, with a 1.75-inch outer diameter and a depth of about 1.00 in.

What it is

A piston cup is the flexible sealing element fitted to the piston in the fluid end. It maintains the seal against the cylinder liner bore as the piston reciprocates, so wear here directly affects volumetric efficiency.

Specifications

Property	Value
Weight	0.03 lb (≈ 0.01 kg, converted)
Width	1.75 in / 4.5 cm
Height	1.75 in / 4.5 cm
Depth	1.00 in / 2.5 cm

Manufacturer technical notes

Piston Cup 1.75 OD CXV-BN (SKU:5259944) HNBR/NBR composite rubber (hardness Shore A 70±5) with vulcanization molding (crosslinking ≥90%), compatible with API 7K mud pumps (pressure differential resistance ≥50MPa), temperature range -35℃~150℃, fits FMC Bean high-pressure systems.

Verbatim from the Dongli product page on dlhddrilling.com.

Replacement / interchange

Aftermarket replacement cross-referencing FMC Bean 5259944.

FAQ

What does the '1.75 inch OD' in the name mean?: 1.75 inch OD is the outer diameter of the piston cup; the depth is about 1.00 in.
What does this piston cup do?: It is the flexible sealing element on the piston in the fluid end. It maintains the seal against the cylinder liner bore as the piston reciprocates, so wear at the cup directly affects volumetric efficiency.
What is the cross-reference for this piston cup?: It is an aftermarket replacement for FMC Bean part 5259944; the brand and part number are listed only for identification and cross-reference, not to claim factory manufacture.

Related parts

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All brand names, model numbers and part numbers are used for identification and cross-reference only and do not imply original-equipment manufacture. This is an aftermarket replacement part.

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