Don’t forget stuffing box maintenance

The Industrial Internet of Things (IIoT) empowered plants to implement condition monitoring more extensively with inexpensive sensors. The influx of stick-it-and-forget-it vibration sensors for pumps and motors alone has been monumental. However, you can’t use these sensors and other IIoT technology to monitor every possible fault and all types of equipment.

About the Author: Lori Ditoro

Lori Ditoro joined Sealing Equipment Products Company Inc. in November 2018 as content marketing manager. Before that, she was content marketing strategist for Fluke Accelix and editorial director of several industrial publications. In her roles, Ditoro learned about the process and manufacturing industries, and the equipment that keeps plants and other facilities operating. She also developed a passion for telling operators’ and technicians’ stories. She may be reached at [email protected].

COVID-19 and IIoT acceleration

In March 2020, the COVID-19 pandemic brought the globe to a standstill. While essential businesses and manufacturers continued to operate, many did so with smaller staffs, to ensure social distancing or because of infections among personnel. Outside consultants and vendors were prohibited, and teams had to maintain equipment without this support.

An April 2020 article from McKinsey & Company articulated the added demands for facilities as COVID-19 spread globally: “Companies are suddenly dealing with remote work on a large scale, as well as new concerns about protecting their remaining on-site employees, and have adapted their workforce organization in consequence.”

Among the challenges the authors discuss are:

limiting team members to allow for social distancing
changing shift times and breaks
reorganizing the workplace (again to allow for distancing).

In these situations, IIoT tools can help with these adjustments to staffing and remote work.

The need and desire to add condition monitoring sensors and digital access ramped up exponentially in the second quarter of 2020. However, for many reasons, including economic feasibility and asset criticality, visibility into every asset with condition monitoring sensors is not always reachable.

The difficult-to-monitor stuffing box

Sensor technology enables personnel safety, increased equipment uptime, and minimized personnel on the plant floor. However, some equipment may not be critical enough for sensors, and some simply cannot be monitored with this technology.

For example, you cannot readily monitor a stuffing box (also called a seal chamber) on a pump with available technology (see Figures 1 and 2). A recent presentation during the Leading Reliability virtual event in January reinforced this. When asked what sensor or IIoT technology could be used to remotely monitor a stuffing box, the experts presenting from Fluke Reliability said visual inspection and/or failure mode and effects analysis (FMEA) would be the ideal method. An FMEA of a stuffing box may reveal some of failure modes shown in Table 1. However, this analysis will be conducted after a failure, but the results could prevent a future failure if the team pinpoints the true root cause of the failure.

Your Space

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This area of a pump may fail in several different ways. The examples shown in Table 1 illustrate a few. Because teams often underestimate the stuffing box’s importance to the system, they fail to optimize the seal technology to ensure reliability. Many teams don’t prioritize the stuffing box until problems recur. Is a technology available to monitor this, if a pump is classified at critical? The short answer is: Not really.

Ultrasound: A possibility for condition monitoring

Ultrasound may be the most promising technology for monitoring this part of a pump. However, as a sensor technology today, it is not an option. Adrian Messer, director of U.S. Operations for UE Systems, discussed the use of ultrasound for this type of monitoring. Some people may use airborne ultrasound to detect seal leakage, and he could see where it might be possible to use it in this way. However, Messer has not conducted this type of monitoring inspection on seals or stuffing boxes.

Data collection with ultrasound is traditionally route-based using a handheld ultrasound device. However, according to Messer, the use of sensors is increasing, and two factors driving this upturn:

lack of manpower to do traditional route-based inspections
the need for the maintenance personnel to do more productive tasks instead of route-based data collection.

Most new plants being built have sensors/IIoT as the main focus. They want to be sensor- and data-driven, Messer indicated.

“We have really put a focus on asset condition monitoring applications like bearings and rotating equipment. We have recently released some new products and have more in the works, slated to be released over the next several months, that can fit into a lot of these IIoT initiatives,” Messer says.

Looking forward

The initial narrative (and honestly, fear) around IIoT technology was that sensors may replace the need for personnel in a plant. However, examples like stuffing box monitoring reinforce that personnel will continue to be needed on the plant floor. The future of maintenance and reliability continues to require human input on the floor.

“IIoT technology is wonderful and has a lot of upside for the future,” says Shon Isenhour, founding partner, Eruditio. “However, not every plant is ready for it quite yet. Additionally, we will not be able to have visibility into every asset or every critical failure mode for the foreseeable future with existing technology. We will still need to continue to use route-based maintenance and visual inspections to monitor some of our assets, likely including the stuffing boxes of our pumps.”