Industry & Background

This case study features a major paper manufacturer, one of the largest in Japan. The company's manufacturing plant handles all processes from pulp processing to final product finishing in an integrated manner.

Paper manufacturing involves handling large volumes of diverse fluids including water, steam, chemicals, and pulp slurry. Thousands of valves are installed throughout the plant to control these fluids, and their proper operation forms the foundation of stable operations.

Steam is an indispensable utility for the drying process, with numerous large-diameter steam valves in use. Important valves are also positioned throughout chemical injection control and wastewater systems, creating an environment where fluid control reliability directly impacts production quality.

Over years of continuous operation, equipment aging has become an unavoidable challenge. In particular, confirming the internal condition of valves has been recognized as one of the most difficult issues in facility management.

Challenge

Many of the valves used in paper manufacturing plants are large-diameter and play critical roles in fluid control. However, corrosion and degradation from years of operation had progressed in these valves, with an ever-present risk of internal leaks (leakage through the valve seat).

The biggest problem was that virtually no means existed to directly confirm valve internal leaks. Most of the plant's valves were wrapped in insulation material, making it impossible to visually inspect the valve body from outside. Furthermore, corrosion on the piping surface made it difficult to infer the internal condition from the valve's external appearance.

On-site maintenance personnel could only rely on visual and auditory inspections even when internal valve leaks were suspected. While steam leak sounds could indicate anomalies, detection was difficult for minor leaks or in noisy environments, and oversights had become routine.

Accurately confirming internal leaks required disassembling the valves, but disassembling large-diameter valves required several days of line shutdown and substantial labor. Consequently, internal leak detection had effectively been an "abandoned challenge" left unaddressed for years.

Product Adopted

To solve this challenge, the valve internal leak inspection device "VALVE SENSE (LL-VS1)" was adopted. VALVE SENSE is a portable measurement instrument that detects internal valve leaks non-destructively by acoustically analyzing fluid behavior within piping.

For implementation, inspection ports (small-diameter measurement holes) were installed on the piping upstream and downstream of the valves. By connecting VALVE SENSE sensors to these inspection ports, the presence of fluid passing through the valve seat can be detected with high accuracy.

The greatest advantage of this approach is that internal leaks can be accurately determined even when valves are wrapped in insulation or when external corrosion has progressed. Information that previously could only be obtained through disassembly is now accessible through non-destructive inspection from outside the piping.

Inspection port installation is performed during scheduled maintenance, and once installed, repeated measurements are possible. Measurements themselves are completed in minutes, allowing integration into routine patrol activities. Measurement data is digitally recorded, enabling tracking of changes over time.

Results

The adoption of VALVE SENSE enabled early detection of previously undetectable internal leaks. During the initial survey immediately after deployment, multiple valves were found to have internal leaks greater than expected, revealing that energy had been wasted for years.

By implementing prioritized planned repairs for the detected internal leaks, waste of steam and hot water was significantly reduced, achieving visible energy cost reductions. The impact of steam system valve repairs was particularly significant, also contributing to reduced boiler loads.

Significant improvements were also seen in safety. Early detection of internal leaks in chemical system valves reduced the risk of unintended chemical contamination, improving operational safety. Environmental contamination risks from leaks were also mitigated.

Furthermore, the accumulation of regular measurement data now enables advance understanding of valve degradation trends. This has made preventive maintenance practical, dramatically reducing the frequency of unplanned shutdowns due to sudden valve failures. The company has simultaneously achieved improved equipment uptime and optimized maintenance costs.

  • Non-destructive detection of internal leaks even under insulation and corrosion
  • Significant reduction in steam and hot water energy losses
  • Improved safety of chemical systems and reduced environmental risk
  • Data-driven preventive maintenance reducing unplanned shutdowns
  • Overall equipment uptime and reliability improved