/Inside the pump
3D render
Inside a VX pump, part by part
A VX 65-50-200 pump set shown apart in the order a fitter strips it, with each of its eleven parts explained.
Every pump
runs on our test loop before it ships
5
Five shops, one works
VX 65-50-200
Eleven parts, one pump
The pump comes apart, then each part is explained in turn.
Skip to the parts table
Exploded view of the VX 65-50-200, rendered from the site's own 3D model. Part numbers match the cards below.
VX 65-50-200
An end-suction pump set: casing, rotor, bearing frame, coupling and motor on one baseplate.
Duty
50 m³/h at 50 m
Speed
2,900 min⁻¹
Motor
11 kW, IE3
Parts
Eleven, numbered as on the assembly drawing
1
Volute casing
Catches water leaving the impeller and slows it in a widening spiral, so speed becomes pressure. Suction enters at the eye; discharge leaves tangentially at the top.
Material
Grey iron EN-GJL-250; ductile iron or stainless 1.4408 on request
In service
Stays on the pipework: the rest of the pump pulls out backwards
On this pump
DN65 suction · DN50 discharge · PN16
2
Casing wear ring
A renewable ring where the impeller eye runs inside the casing. It keeps the leak from discharge back to suction small.
Material
Grey iron EN-GJL-250; ductile iron or stainless 1.4408 on request
In service
Stays on the pipework: the rest of the pump pulls out backwards
On this pump
DN65 suction · DN50 discharge · PN16
3
Impeller nut
Clamps the impeller to the shaft against its key. The thread is cut so that normal rotation tightens it.
Material
Grey iron EN-GJL-250; ductile iron or stainless 1.4408 on request
In service
Stays on the pipework: the rest of the pump pulls out backwards
On this pump
DN65 suction · DN50 discharge · PN16
4
Impeller
Six backward-curved vanes between two shrouds fling the water outwards, adding speed and pressure. Shown with part of the front shroud cut away.
Material
Grey iron EN-GJL-250; ductile iron or stainless 1.4408 on request
In service
Stays on the pipework: the rest of the pump pulls out backwards
On this pump
DN65 suction · DN50 discharge · PN16
5
Casing cover
Closes the back of the volute and forms the seal chamber. It bolts to the bearing frame, so it leaves with the rotating unit.
Material
Grey iron EN-GJL-250; ductile iron or stainless 1.4408 on request
In service
Stays on the pipework: the rest of the pump pulls out backwards
On this pump
DN65 suction · DN50 discharge · PN16
6
Mechanical seal
Stops liquid escaping where the shaft leaves the casing. A spring presses a rotating face against a stationary one, with a liquid film thinner than a micron between them.
Material
Grey iron EN-GJL-250; ductile iron or stainless 1.4408 on request
In service
Stays on the pipework: the rest of the pump pulls out backwards
On this pump
DN65 suction · DN50 discharge · PN16
7
Bearing frame
Holds both bearings in line with the casing and carries the oil. Its foot takes pipe loads so the shaft stays straight.
Material
Grey iron EN-GJL-250; ductile iron or stainless 1.4408 on request
In service
Stays on the pipework: the rest of the pump pulls out backwards
On this pump
DN65 suction · DN50 discharge · PN16
8
Bearings
A deep-groove ball bearing near the impeller takes the radial load. A pair of angular-contact bearings at the drive end takes the axial thrust.
Material
Grey iron EN-GJL-250; ductile iron or stainless 1.4408 on request
In service
Stays on the pipework: the rest of the pump pulls out backwards
On this pump
DN65 suction · DN50 discharge · PN16
9
Shaft
Carries the impeller and passes the motor's torque along. It is kept short and stiff so it barely bends at the seal faces.
Material
Grey iron EN-GJL-250; ductile iron or stainless 1.4408 on request
In service
Stays on the pipework: the rest of the pump pulls out backwards
On this pump
DN65 suction · DN50 discharge · PN16
10
Coupling
Joins pump shaft to motor shaft. An elastomer spider between two jaw hubs absorbs small misalignment and shock loads.
Material
Grey iron EN-GJL-250; ductile iron or stainless 1.4408 on request
In service
Stays on the pipework: the rest of the pump pulls out backwards
On this pump
DN65 suction · DN50 discharge · PN16
11
Motor
A two-pole, fan-cooled induction motor turns the shaft at 2,900 revolutions a minute, sized with margin over the pump's power at the end of its curve.
Material
Grey iron EN-GJL-250; ductile iron or stainless 1.4408 on request
In service
Stays on the pipework: the rest of the pump pulls out backwards
On this pump
DN65 suction · DN50 discharge · PN16
Data shown for an example VX 65-50-200 configuration at 50 m³/h and 50 m head. The model is drawn for explanation and is not a dimensioned drawing.
Reference
Parts reference
The same eleven parts as a table, numbered as on the assembly drawing. Quote the casing number when ordering spares.
No.
Part
Function
Material
In service
1
Volute casing
Catches water leaving the impeller and slows it in a widening spiral, so speed becomes pressure. Suction enters at the eye; discharge leaves tangentially at the top.
Grey iron EN-GJL-250; ductile iron or stainless 1.4408 on request
Stays on the pipework: the rest of the pump pulls out backwards
2
Casing wear ring
A renewable ring where the impeller eye runs inside the casing. It keeps the leak from discharge back to suction small.
Bronze CuSn10
When the gap opens up, change the ring, not the casing
3
Impeller nut
Clamps the impeller to the shaft against its key. The thread is cut so that normal rotation tightens it.
Stainless 1.4021
Replace the lock washer every time it comes off
4
Impeller
Six backward-curved vanes between two shrouds fling the water outwards, adding speed and pressure. Shown with part of the front shroud cut away.
Bronze CuSn10; grey iron or stainless 1.4408
Trimmed to your duty; check vane tips for erosion at overhaul
5
Casing cover
Closes the back of the volute and forms the seal chamber. It bolts to the bearing frame, so it leaves with the rotating unit.
Grey iron EN-GJL-250
Its spigot locates the rotor; keep the faces clean on refit
6
Mechanical seal
Stops liquid escaping where the shaft leaves the casing. A spring presses a rotating face against a stationary one, with a liquid film thinner than a micron between them.
Carbon against silicon carbide, EPDM elastomers
Never run it dry; a seal that weeps steadily needs new faces
7
Bearing frame
Holds both bearings in line with the casing and carries the oil. Its foot takes pipe loads so the shaft stays straight.
Grey iron EN-GJL-250
Read the oil level in the sight glass weekly
8
Bearings
A deep-groove ball bearing near the impeller takes the radial load. A pair of angular-contact bearings at the drive end takes the axial thrust.
Bearing steel
Change on condition: listen, feel temperature, measure vibration
9
Shaft
Carries the impeller and passes the motor's torque along. It is kept short and stiff so it barely bends at the seal faces.
Steel C45; stainless 1.4021 for wetted service
Check runout at the seal seat after any heavy knock
10
Coupling
Joins pump shaft to motor shaft. An elastomer spider between two jaw hubs absorbs small misalignment and shock loads.
Grey iron hubs, polyurethane spider
Inspect the spider at every alignment check
11
Motor
A two-pole, fan-cooled induction motor turns the shaft at 2,900 revolutions a minute, sized with margin over the pump's power at the end of its curve.
Cast-iron frame, copper windings
Keep the fan cowl clear of dust and lagging
Need spares for a VX?
Seal, wear-ring and bearing kits are matched to your pump by its casing number.
Spares and kits
Got a duty point?
Let’s size your next pump.
Send flow, head and the liquid. An engineer replies with a selection, a curve and a price.
Stay connected
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Contact info
Working hours
Mon to Fri: 08:00 – 17:00
Test loop visits by appointment
Sat and Sun: closed
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