Preventing failure in wastewater inlet screws

Preventing failures in wastewater inlet screws holds significant importance on the agenda for water companies as it helps avert breakdowns and pollution events.

In this case study you will learn:

• How wastewater companies prevent inlet screw failures using SAM4 Health from Samotics
• How SAM4 Health catches the top three screw pump failure modes remotely and in advance
• How a typical SAM4 Health belt detection on wastewater inlet screws looks like

How wastewater companies prevent inlet screw failures using SAM4 Health from Samotics

1. SAM4 Health installs remotely inside the motor control cabinet or in the cabinet near the local motor starter.
2. SAM4 Health continuously monitors voltage and current to detect developing faults soon after they start. In particular, it will catch the top 3 screw failure modes well in advance: gearbox, belt and motor bearing problems.
3. SAM4 Health alerts the customer in the online dashboard and by email.
4. The customer schedules maintenance at a convenient time, after which SAM4 Health confirms the asset’s return to healthy behavior.

SAM4 Health catches the top three screw pump failure modes remotely and in advance

SAM4 Health works on the principle of electrical signature analysis (ESA). Subtle changes in a machine’s operation affect the motor’s magnetic field, which then affects the supply voltage and operating current. By analyzing these changes, SAM4 Health is able to detect all electrical and many mechanical faults much earlier than systems using vibration, temperature, or other indicators. In particular, SAM4 Health can catch the top three inlet screw failure modes up to five months in advance, all from the remote safety of the motor control cabinet. (Learn more about how ESA works in our technology explainer.)

For example, in the typical path to belt failure, early stress on the belt goes unnoticed by standard vibration and visual inspections. By the time these methods can pick up on the problem, the belt is near the end of its useful life. It’s often a matter of luck whether the issue will be caught in time to prevent total failure. Not so for SAM4 Health: it will see the problem when it starts, thanks to remote, continuous analysis of the current and voltage signals. With this amount of advance notice, you will be able to schedule a work order for belt tensioning or replacement at a convenient time well before the screw is in danger of failing.

Typical path to belt failure on inlet screws

1. Operational stress on the screw puts stress on the gearbox, which puts stress on the driven pulley, which puts torsional stress on the belt and, over time, causes it to degrade. Eventually the belt snaps and the screw fails, requiring significant repairs and emergency mitigation to avoid a pollution event.
2. SAM4 Health
   This torsional stress produces immediate changes in the screw pump’s electrical signals at belt-related frequencies. SAM4 Health’s algorithms flag this change and generate a notification.
3. SAM4 HEALTH
   This means you have plenty of time to schedule belt retensioning or replacement at a convenient time.
4. VIBRATION
   Vibration monitors typically won’t uncover the issue until the belt is so damaged it starts producing lateral and axial vibrations.
5. Which means there might not be enough time to schedule and conduct repairs before the belt ruptures.
6. INSPECTION
   Manual inspections typically won’t uncover the issue until the belt is so damaged it makes audible noise.

Inside a typical SAM4 Health belt detection on wastewater inlet screws

1. SAM4 Health’s machine learning algorithms detect rising energy in one of the belt pass scorers for the inlet screw pump. The customer is notified of the problem and its severity in the online dashboard and by email.
2. The customer schedules a work order to retension or replace the belt at a convenient time.
3. SAM4 Health continues to monitor the belt scorer (as well as all its other scorers for the inlet screw pump). The customer receives dashboard and email updates on the situation and any change in severity.
4. The customer performs maintenance and reports back to Samotics, by email or in the dashboard.
5. SAM4 Health confirms a return to normal behavior and notifies the customer that their actions have resolved the problem.

How SAM4 Health will change your screw pump maintenance

SAM4 Health starts improving your operations right away. Faults are now being caught early, when repairs are faster and cheaper and can be optimally scheduled into your maintenance agenda. This will quickly drive down the cost of repairs, inspections and emergency mitigation. Over time, as SAM4 Health accumulates vast amounts of screw performance and health data, the system will present you with long-term insight reports.

This will enable you to move from reactive to predictive maintenance — from scrambling to recover from failures to finally having the resources to find and fix the root cause of them. The potential savings from this change in approach are enormous — not only in terms of time and money, but also in long-term colleague satisfaction and public goodwill.