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Double-Suction Impeller

Flow enters from both sides, so the axial thrust largely cancels itself.

Double-Suction Impeller

Flow enters from both sides, so the axial thrust largely cancels itself.

Two mirrored sets of vanes share one hub. Each half takes roughly half the flow, and because they face opposite directions the axial loads they generate pull against each other instead of into the thrust bearing.

The catch is that the two halves have to match. If one side is cast fuller than the other the thrust does not cancel — and an imbalance that a single-suction pump would carry on its thrust bearing becomes a load nobody designed for.

Casting process	Vertical-line sand moulding on two lines (national patent)
Materials	Grey iron · ductile iron · WCB carbon steel · CF8M stainless
Machined features	Bore and keyway · hub faces · both eye diameters · balance correction
Minimum order	100 pieces
Certification	EN 10204 3.1 per heat, spectrometer results
Source of geometry	Your drawing, 3D file or a worn sample

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Casting Notes

What Is Difficult About This One

Every casting has one or two features that decide whether the batch repeats. On this part they are these.

Two halves have to match

Symmetry between the mirrored passages is the whole point of the construction. Core location is held tighter here than on any other impeller we run.

Two enclosed passages, one core assembly

Both sides are cored and both have to break out after shakeout, from a part with no external access to either.

Balanced, and the residual recorded

Dynamically balanced to ISO 1940 with the grade stated on the report. On a double-suction wheel the balance report is also the evidence that the halves matched.

Materials

Alloy Options

The same geometry is a different part in three different plants. Chloride content, abrasion and temperature drive the choice — not the name of the fluid.

Alloy	Grade	When it is the right choice
Grey iron	HT200 / HT250	Default for water duty. Damps vibration, machines easily, lowest cost.
Ductile iron	QT450 / QT500	When the duty is cyclic or the part takes shock. Tougher than grey.
WCB carbon steel	ASTM A216 WCB	Higher strength, weldable. For pressure-bearing bodies.
CF8M stainless	ASTM A743 CF8M	Chloride and corrosion duty — the cast equivalent of 316.

Enquiry

What to Send Us

These are the ones specific to this part. A drawing, a 3D file or the worn original covers all of them at once.

Item	Why it matters
Shaft diameter and key size	Bore and keyway
Vane count and outlet angle	Or the worn impeller — we reconstruct from it
Direction of rotation	From the drive end
Balance grade	ISO 1940 G6.3 unless you specify finer