Pump parts are the components of pumps that move liquids and slurries from one point to another and that wear, deteriorate or fail. In mining and crushing and screening plants two groups of pumps are especially important: slurry pumps used in washing plants, hydrocyclone feed and thickeners, and the oil pumps of crushers, gearboxes and hydraulic systems. Slurry pumps wear continuously because of abrasive pulp, while oil pumps protect the crusher’s most critical parts from running dry.
For our range of pump spare parts see our pump spare parts page. In this guide we look in detail at the parts of a centrifugal pump, slurry pump wear parts, gland packing and mechanical seal options, the role and failure symptoms of an oil pump, pump maintenance and spare parts planning.
Parts of a Centrifugal Pump
| Part | Function | Wear / Failure |
|---|---|---|
| Impeller | Imparts energy to the liquid | Wear, cavitation, broken vanes |
| Casing (volute) | Collects the liquid and directs it to the discharge | Wear, holing |
| Casing liners (metal or rubber) | Protect the casing from wear | Loss of thickness |
| Throat bush / front liner | Sets the clearance between impeller and casing on the suction side | Wear, increased clearance, loss of efficiency |
| Frame plate liner (back liner) | Protects the back | Wear |
| Shaft and shaft sleeve | Transmits torque; the sleeve protects the shaft in the seal area | Sleeve wear |
| Gland packing or mechanical seal | Seals where the shaft exits | Leakage, wear |
| Bearing assembly | Supports the shaft | Temperature, vibration |
| Expeller (dynamic seal) | Provides sealing without packing on some slurry pumps | Wear |
Slurry Pump Wear Parts
Because slurry pumps carry abrasive pulp containing sand and fine stone, their wear parts are replaced continually. Material is selected according to the character of the pulp:
| Material | Suitable Conditions |
|---|---|
| High-chrome white iron | Coarse, sharp-grained, abrasive pulp |
| Natural rubber liners | Fine-grained pulp; rubber resists abrasion by fine particles very well |
| Polyurethane | Fine–medium pulp, some chemical environments |
| Synthetic rubbers | Chemical resistance or oil-bearing environments |
Rubber liners can be cut by coarse, sharp particles or at tip speeds high enough to damage the rubber; metal parts are preferred in that case. Choosing the right impeller and liner materials together significantly extends pump life.
Throat Bush Clearance and Efficiency
As the clearance between the impeller and throat bush grows with wear, some of the pumped pulp recirculates to the suction side. This reduces pump pressure and flow and accelerates wear further. On many slurry pumps this clearance can be adjusted by moving the bearing assembly axially. Regular clearance adjustment improves both efficiency and part life.
Shaft Sealing Options
| Type | Advantage | Caution |
|---|---|---|
| Gland packing (braided packing with gland follower) | Simple, economical, easy to maintain on site | Needs gland water; adjustment and sleeve wear must be monitored |
| Expeller (dynamic seal) | Reduces the need for gland water | Limitations depending on suction pressure |
| Mechanical seal | Low leakage and water consumption | Higher cost; sensitive to dry running and incorrect fitting |
Pump Failure Symptoms
| Symptom | Possible Cause |
|---|---|
| Drop in flow and pressure | Impeller and throat bush wear, increased clearance |
| Noise and vibration (gravel sound) | Cavitation; blocked suction line, low sump level |
| Excessive leakage from the gland | Packing wear, sleeve wear, insufficient gland water |
| Bearing overheating | Lubrication, misalignment, belt tension |
| Motor overload | Pulp density too high, impeller rubbing |
On pumps feeding hydrocyclones, a drop in flow and pressure directly impairs cyclone performance; for details see our hydrocyclone guide.
What Is an Oil Pump and What Does It Do?
An oil pump draws oil from the tank in a lubrication system and delivers it under pressure to bearings, bushings and gears. If the oil pump stops on a crusher, large gearbox, mill or engine, the oil film breaks down quickly and bushings, bearings and gears can be badly damaged. For this reason oil pressure and flow are monitored continuously on crusher lubrication units, and the crusher is stopped automatically if pressure falls.
- Types: Gear pumps (most common), screw pumps, vane pumps.
- Failure symptoms: Falling oil pressure, louder pump noise, changes in motor current, rising oil temperature.
- Failure causes: Dirty oil and wear, blocked suction strainer, cold and thick oil, air ingress, coupling and motor problems.
- Maintenance: Filter changes, suction line checks, oil analysis, pressure and flow records.
For maintenance of the pump, filters and cooler of a crusher lubrication unit see our crusher lubrication unit guide, and for hydraulic pumps see our hydraulic system maintenance guide.
Pump Maintenance Plan
| Frequency | Check |
|---|---|
| Daily | Noise, vibration, gland leakage, gland water, pressure |
| Weekly | Bearing temperature, belt tension, connections |
| Monthly | Throat bush clearance adjustment (slurry pumps), oil level |
| Periodic | Impeller and liner thickness measurement, bearing oil change |
| Overhaul | Wear parts, sleeve, seal, bearing assembly |
Spare Parts Planning
- For critical slurry pumps, keep an impeller, throat bush, casing liners and a seal set in stock.
- Holding a standby pump or spare bearing assembly on critical lines minimises downtime.
- Standardising pump models and sizes across the plant reduces stock variety.
- For the crusher lubrication unit, keep a spare oil pump or pump–motor set and filter elements.
Frequently Asked Questions
What are the parts of a pump?
The main parts of a centrifugal pump are the impeller, casing, liners, throat bush, shaft and sleeve, gland packing or mechanical seal, and bearing assembly.
How can you tell an oil pump is failing?
Falling oil pressure, a change in pump noise, rising oil temperature and pressure alarms are the main signs.
Rubber or metal for a slurry pump?
Rubber liners usually last longer with fine-grained pulp; high-chrome metal parts are preferred with coarse, sharp-grained pulp.
What is cavitation?
The collapse on the impeller of vapour bubbles formed when pressure drops at the pump suction; it causes noise, vibration and pitting of the impeller.
Points to Consider When Selecting a Slurry Pump
- Flow and head: Including process requirements such as hydrocyclone feed pressure.
- Pulp properties: Solids concentration, particle size distribution, solids density, abrasiveness.
- Chemical environment: pH and chemical content affect material selection.
- Suction conditions: Sump level and suction line design determine cavitation risk.
- Speed: A larger pump running at lower speed generally wears less.
- Drive: A belt drive gives flexibility in speed adjustment (belt guide).
Factors Affecting Pump Part Prices
| Factor | Effect |
|---|---|
| Pump size | Part weight and size |
| Material | High-chrome iron, rubber, polyurethane |
| Seal type | Mechanical seals cost more than gland packing |
| OEM or aftermarket | Aftermarket parts are usually more economical |
| Lead time | Stock availability and manufacturing time |
Glossary
- Impeller: The rotating element that imparts energy to the liquid.
- Throat bush: The wear part on the suction side.
- Gland packing: The sealing element where the shaft exits.
- Cavitation: Damage caused by the collapse of vapour bubbles.
- NPSH: Net positive suction head required for the pump to run without cavitation.
- Pulp: A mixture of water and solid particles.
More Questions
What happens if the oil pump fails?
Lubrication stops; bushings, bearings and gears heat up quickly and can be damaged. This is why crushers have automatic shutdown on low oil pressure.
What are the parts of a centrifugal pump?
The impeller, casing (volute), liners, throat bush, shaft, shaft sleeve, seal and bearing assembly are the main parts.
CSP Mühendislik Support
CSP Mühendislik supports the supply of impeller, liner and seal parts for washing plant slurry pumps, and pump, filter and cooler parts for crusher lubrication units. See our pump spare parts page for pump parts, our screw washer spare parts page for washing plant parts and our cone crusher spare parts page for crusher lubrication parts; for all products see our spare parts page.
