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Open Impeller

No shroud at all — vanes on a hub, clear through from both sides.

Open Impeller

No shroud at all — vanes on a hub, clear through from both sides.

The construction for fluids that would wrap or bridge anywhere else: stringy solids, fibre, rag. There is nothing for material to catch on, and anything that enters the eye goes out of the periphery.

Efficiency is the lowest of the three constructions, and it falls further as the clearance to the casing opens up. That is understood when this impeller is specified — it is chosen because the pump keeps running, not because it runs efficiently.

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 · vane tip diameter · 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.

Vanes are cantilevered

With no shroud on either side the vanes carry their own load. Section at the root is generous and the fillet is large.

Simplest mould, thinnest sections

Nothing enclosed, but nowhere for heat to go either. Pouring temperature does more work here than the gating layout.

Balance matters more, not less

Less material means a given imbalance is a larger fraction of the mass. Every one is dynamically balanced.

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
What is in the fluid	Fibre, rag or stringy solids — it is why you are choosing open
Shaft diameter and key size	Bore and keyway
Casing clearance available	Sets the vane width you can run