Equipment Maintenance: Thermal Imaging Changes the Picture

Pharmaceutical plant benefits by taking a different look at equipment.

By Jeff Fleming, CMC icos Biologics, Inc.

2 of 3 1 | 2 | 3 View on one page

Steam traps. We scan our steam traps at least semi-annually. A well-functioning trap should have a high inlet temperature and a lower outlet temperature (Figure 2 at left — in this case, there’s a difference of 70°F). In Figure 2 at right the trap has failed open. There’s only a 20°F difference between the inlet and the outlet. A trap as large as this one holds a lot of heat and should show a significant difference.

Cold room. Here, product is stored near freezing but must not freeze. Sensors mounted throughout the room monitor it but we use the thermal imager, too. We were concerned about the floor as well as the product freezing, so we went through with the camera to get a complete picture. The thermal view was very useful for quality control and for ongoing evaluation. The thermals also served as a baseline on how the room was operating.

Hot room. We use the thermal imager in our server room to compare ambient air temperature against a wall-mounted sensor, as a quality control check.

Coping with stainless steel
Figure 3. Coping with stainless steel: Using a lattice
of tape on a stainless steel tank enables inspection
of its insulation.

Tanks. Our tanks are stainless steel, which makes monitoring their insulation difficult. Of the three kinds of energy that can be emitted from an object — reflected, transmitted and emitted — only emitted IR energy indicates the object’s surface temperature. Energy reflected from a shiny stainless steel tank recorded by a thermal imager doesn’t represent the true surface temperature. To compensate, we place paper tape in a lattice pattern on tanks to monitor soundness of interior insulation. The tape quickly reaches the temperature of the surface beneath, allowing us then to make a valid reading. Figure 3 shows an example of the lattice pattern. In this case we were inspecting for suspected bad insulation in the steam jacket. This image indicated the jacket was warm, not overly hot, disproving our theory.

Refrigeration units. We have multiple refrigerators, freezers and stability chambers (very precise temperature/humidity control devices). I need to verify their internal controls. Stability chambers in particular only should fluctuate within ½°C. We were having temperature control issues with a stability chamber. We inspected it and noticed the door was misaligned. I got the thermal imager, scanned the door, and saw the seam was cool instead of hot — it was leaking cold air. We now will scan all refrigeration units semi-annually to check for seal failures to preempt temperature control issues.

Heat exchangers. I regularly inspect the several heat exchangers on site with the thermal imager to ensure they’re operating efficiently and their insulation is sound. Before having the imager in house, I had to guess whether the exchangers needed repair or wait until problems arose.

Figure 4 illustrates both a well-insulated unit (left) and a unit with insulation problems. The left image shows hot going in and cold coming out, with very little leakage. I checked temperatures at the joint at the top left and to the heat exchanger at right, and I scanned the exchanger’s insulation.
 Heat exchanger insights Heat exchanger insights 
 Fig.4. Heat Exchanger Insights
 The heat exchanger on the left
2 of 3 1 | 2 | 3 View on one page
Show Comments
Hide Comments

Join the discussion

We welcome your thoughtful comments.
All comments will display your user name.

Want to participate in the discussion?

Register for free

Log in for complete access.


No one has commented on this page yet.

RSS feed for comments on this page | RSS feed for all comments