Valves, Actuators & Pump Control


Optimised pump ­performance

May 2018 Valves, Actuators & Pump Control

Ignoring pumps is a risk because when these components break down, or run below optimum efficiency, the whole process suffers. Manufacturing and process companies are always under cost pressure, making it vital to maximise assets and maintain uptime.

SKF has identified four different ways to optimise pump performance:

The right bearing

Bearings in centrifugal pumps support hydraulic loads imposed on the impeller, the mass of the impeller and shaft, as well as loads due to couplings and drive systems. They also keep the shaft axial and radial deflections within acceptable limits for the impeller and shaft seal. The bearings often will face high axial loads, marginal lubrication, and high operating temperatures and vibration, all while the bearings attempt to minimise friction, which, if uncontrolled, can result in power loss, excessive heat generation, increased noise or wear, and early bearing failure. So, first and foremost, evaluate bearings (types, designs and arrangements) in the context of their anticipated operating environment. Suitable bearings are available to satisfy even the most difficult conditions faced by centrifugal pumps.

Proper lubrication

Improper lubrication accounts for more than 30% of bearing failures. Good lubricants prevent metal-to-metal contact and undesired friction. The common methods for the effective lubrication of pump bearings include: grease, oil bath, oil ring, oil mist and air-oil.

Oil mist generates the least amount of friction (allowing rotational speed to be based on the bearing design instead of lubrication limitations) and creates a positive pressure within the bearing housing (fending off invasive contaminants). Regardless of lubrication method, always specify lubricant according to the demands on vertical shafts and resistance to solids, pressure, temperatures, loads and chemical attack.

Sealing the system

Bearing seals in centrifugal pumps handle four crucial tasks. They retain lubricants or liquids, exclude contaminants, separate fluids and confine pressure. The choice of seal for centrifugal pump bearings depends on the unique demands and operating conditions of the application. Keep in mind, though, that the bearing and sealing arrangement represent an integrated system. Dynamic radial seals generally are the best choice for centrifugal pumps. These seals create the barrier between surfaces in relative motion. Seal selection ultimately must be based on a thorough review of application parameters and environmental factors.

Particularly in pump applications, for example, seals will be exposed to relatively constant pressure differentials, making pressure seals (in which the seal cavity is pressurised) the preferred choice. Seals usually provide a much shorter life than the components they protect so don’t fall into the common habit of scheduling seal replacement only at intervals dictated by requirements of other components such as bearings.

Monitoring pump health

Regular measurement and analysis of key physical parameters, such as vibration and temperature, can detect pump system problems before they occur. Basic instruments can assess and report on vibration, temperature and other parameters. More advanced tools include online surveillance systems and software that can deliver real-time data. Many problems will manifest as vibration, which is widely considered the best operating parameter to judge pump train condition. Vibration can detect problems such as imbalance, misalignment, bearing oil-film instabilities, rolling bearing degradation, mechanical looseness, structural resonance and a soft foundation. Vibration measurements are quick and fairly non-intrusive because pump equipment remains undisturbed.

Operators can also play a pivotal part in proactive maintenance strategies by serving as the ‘eyes and ears’ to detect equipment faults before problems escalate and performing basic maintenance activities.

For more information contact Samantha Joubert, SKF South Africa, +27 (0)11 821 3500, samantha.joubert@skf.com, www.skf.co.za


Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

The evolution of partial stroke testing
April 2019, Valve & Automation , Valves, Actuators & Pump Control
The failure of these valves in crucial moments can be catastrophic, potentially rendering useless a Safety Instrumented System (SIS), put in place to reduce the possibility of an accident. Though static ...

Read more...
Stafsjö introduces Linak electric actuator
April 2019, Valve & Automation , Valves, Actuators & Pump Control
Linak’s electric actuator is a compact maintenance-free unit for on/off operations with a speed of 7-11 mm/sec. It is available as standard in a 24 V DC version but it can also work on 230 V AC or 120 ...

Read more...
SKF provides an air-tight solution
Technews Industry Guide: Maintenance, Reliability & Asset Optimisation 2019, SKF South Africa , Maintenance, Test & Measurement, Calibration
When a local vehicle manufacturer experienced air leaks in the pneumatically operated components and systems of the specialised vehicles they construct, the company turned to SKF for assistance. SKF offered ...

Read more...
SKF Test Centre wins design prize at the International Architecture Awards
March 2019, SKF South Africa , News
At The International Architecture Awards in Athens, SKF won a design award for its Sven Wingquist Test Centre. With over 1000 entries from across 31 countries, the awards are globally recognised as a ...

Read more...
SKF offers new metering device for lubrication systems
March 2019, SKF South Africa , Maintenance, Test & Measurement, Calibration
SKF has announced the introduction of its Lincoln SLC metering device for grease. Developed for use in single-line lubrication systems, this compact metering system boasts a modular design for less jointing ...

Read more...
Quarter-turn actuator for harsh conditions
February 2019, Festo , Valves, Actuators & Pump Control
Thanks to its versatility and flexibility, Festo’s quarter-turn actuator DFPD can be used in a variety of applications. Its modern, simple and compact design impresses whether it is used with ball valves, ...

Read more...
Operators step into the future
February 2019, SKF South Africa , IT in Manufacturing
Recognising the increasingly vital role that technology plays in business, SKF continues to move with the Industry 4.0 tide. In line with its ‘World Class Manufacturing’ initiative, SKF has implemented ...

Read more...
SKF runs on predictive maintenance
February 2019, SKF South Africa , Maintenance, Test & Measurement, Calibration
There is an ever-growing need for faster, more efficient production methods and manufacturers are striving to find the perfect balance between product quality and affordability and to deliver within the ...

Read more...
First Metso valves with 3D printed parts
February 2019, Metso South Africa , Valves, Actuators & Pump Control
Metso’s Helsinki plant has delivered the first valves with 3D printed parts. The units include 3D printed metal components that allow them to perform in a particularly demanding application, where they ...

Read more...
Richter’s PFA-lined ball valves
February 2019, Valve & Automation , Valves, Actuators & Pump Control
Richter, a leading supplier of PFA-lined pump and valve solutions, has a new size control ball for its KNR and KNAR valve series. Increasing production quantities in the chemical and petrochemical industries ...

Read more...