Hey Guys how are you doing, for the past month we have focused on temperature measurement. Actually, a short while back, we introduced multipoint temperature assemblies. In this review, we’ll showcase two of the most broadly used technologies in the Oil&Gas industry.

Gayesco | Wika Flex-R vs Daily Thermetrics CatTracker

On one side we have the versatile CatTracker multipoint assembly produced by Daily Thermetrics. on the other side, we have the robust Flex-R from Gayesco|Wika

These products are designed to last for at least 6 years inside petrochemical units under the most extreme conditions, 450 degrees celsius at pressures that go up to 200 bar. Not your common temperature sensor.

This will be a battle of mythological proportions, So prepare yourself for what is coming!so let’s see what conclusions you will have after reading this article.

Full disclosure: This comparison focus on the value proposition from both companies and as well on the differences during installation and service activities, not the performance. If any community members have installed and used these devices, please comment below or send an email to hello@visayasolutions.com with your experiences,  so we all can learn more. Thanks!


The first thing you will notice when you arrive at the warehouse ready to unpack these devices is the size of the box.

Both the CatTracker and the Flex-R are assemblies with multiple temperature sensors that can be up to 20 meters long.

In a way, these products look a giant squid or the mythological Kraken.

The Kraken Vs The Giant Squid

Let’s point out the most significant differences you may see right out of the box.

The first thing you will notice is that CatTracker multipoint has less “limbs” if you compare it with the Gayesco Flex-R.

CatTracker is built with a proprietary sensor technology owned by Daily Thermetrics that allow having multiple thermocouple sensors in one unique sensor sheath. On the contrary, the Flex-R uses individual thermocouple sensors.

A 16 points multipoint, will have 16 individual thermocouple sensors if it built by Gayesco. on the other hand, CatTracker will be packed with 3 or 4 probes, depending on the desired position of the measuring points.

Multipoint Temperature Assembly CatTracker
Source: Wika

The CatTracker is a lighter and less bulky product, this reduces the installation time and the possibilities of channeling on the catalyst bed.

For this reason, the routing of the Flex-R has to be designed according to the reactor dimensions and the measuring point distribution.

Source Daily Thermetrics


Unfortunately, there is no so much information regarding the performance of the multipoint thermocouple sensors. but I will share with you some numbers that you will need when selecting a multipoint temperature assembly.

Measuring Tolerance

The tolerance requirements for thermocouples used in petrochemical reactors is the following; IEC584 Class 1  (± 1,5℃) or ANSI MC 96.1 Class Special (± 1,1℃). Daily Thermetrics offers an ultraprecise thermocouple sensor that has a tolerance of (± 1 ℃).

Daily Thermetrics state there is an Anti-Drift Technology™ in their sensors, but they don’t state what kind of technology it is or how this anti-drift is achieved.

For petrochemical processes, a tolerance below 2℃ is good

Response time

Source: Gayesco International, LP

Gayesco shares the difference between response time compared with traditional temperature measurement technologies. but they don’t state the medium or the sensor construction (grounded or ungrounded).

I would say that for ungrounded sensors the response time between the CatTraker and Flex-R should be quite similar.

Grounded thermocouple sensors should be used if a faster response time is required. Grounded thermocouples are susceptible to electrical noise and are not recommended for most of the petrochemical processes.

Leakage prevention and handling

Both Flex-R and CatTracker are equipped with secondary containment chambers that are able to contain leakage in case the primary welds on the process connection are compromised.

In case the surface of the sensors is compromised, The mineral insulated (MI) cable will lose its insulation, with time this will generate “phantom” hot junctions that will affect the temperature measurement of the sensor.

For this reason, MI cables are built with some of the most advanced metallic alloys available on the market.

Daily Thermetrics uses automatic welding technology that reduces the probability of failure. But you never know; I’ve seen people using these cables as climbing supports during service activities. Yeah, safety what?


As I have stated before, suppliers need the expertise to support end users and EPCs for the design, production, installation and commissioning of this kind of assemblies.

Both companies are equipped with design engineers and service engineers that are able to perform these complex and crucial activities.

Just make sure that during the offering from Daily Thermetrics or Gayesco includes the following test for your product:

  1. Have all retaining welds dye-tested, and test at least 20 percent of the chamber welds with a volumetric method, like X-ray or ultrasonic.
  2. On all thermocouples, inspect continuity and resistance insulation and do three-point calibration at the process temperature.
  3. To increase measurement reliability, inspect the hot joints of every sensor.
  4. Test the process connection and the secondary chamber for hydrostatic pressure around 1.5 times the process pressure.
  5. Use helium to test welds, checking for microcracks.


The higher number of probes of the Flex-R makes heavier and bulkier products since more cables are welded to the chamber and more sensors need to be handled.

The man-hours needed for the installation of a Flex-R will be slightly higher compared with a CatTracker especially for high number multipoint (above 12 points). This is not entirely true in cases where the routing of cables have a lot of bends and turns.

CatTracher thermocouple sensors have a diameter of half an inch (12.7mm) with heavy wall sheaths of 1,7mm, this is a stiffer cable compared with the 5/16″ (7.93mm) with a thickness of what I suppose should be  1.5 mm (20% of the diameter).

Source: ARi Industries, Inc

In any case, you should ask both companies to include a CAD drawing of the sensor installation and the supervision/installation package for your project.

This is a list of best practices taken into consideration when installing a multipoint temperature assembly.

  1. Avoid blocking manways and nozzles with the MI cables.
  2. Route the MI cable through the shadow of the internal structures to avoid condensate, especially near the distribution tray.
  3. For vertical sensors, add length to reduce stress from expansion during operation.
  4.  However, don’t add too much length to avoid channeling between the catalyst layers.
  5. Supporting frames need to follow the requirements of the process licensor.
  6. Install the sensor hot joint at least 200 mm away from the support structure to avoid thermal inertia.
  7. Use experienced installers to speed up installation and reduce potential over costs or damages.

Information and documentation

Here I have to say both Daily Thermetrics and Wika Gayesco can do a better job. I know for a fact that they have high-quality products that are recognized by licensors, EPCs and vessel builders.

But if I had to judge these products using only the information available on their websites I would honestly don’t know from where to start.

The Chinese website for Daily Thermetrics actually has a little more information and some nice pictures of recent projects so kudos to them.

On both websites, there are attached white papers and brochures that you may find useful but it still feels a little outdated.


Multipoint temperature assemblies are some of the most complex devices on the market. Both Daily Thermetrics and Gayesco|Wika are really good companies that are able to support you with your temperature measurement needs.

Make sure to share all your pains with the application engineers from these companies they will find a right solution for you.

If you’ve ever met one of these critters, leave a comment below or send a picture to hello@visayasolutions.com . I’d love to see the beast you have in your plant.

  • Daily Thermetrics
  • Endress+Hauser
  • Gayesco/Wika
  • Thermoelectra
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