Frequently Asked Questions
This technology uses test heat exchangers to monitor the performance of the cooling water system on a continuous basis, real time and allows a visual inspection of the results of the program at skin temperature and velocity.
120volt AC 15-30amp power depending on the model and number of exchangers in the skid.
3 - Model B, C-1 and C-2. These range from single exchanger models (C-1) to 3 exchanger models. Air purge is provided as needed for an additional cost.
A corrosion coupon is not a heated surface and does not have heat transferring through the metal. The SENTINEL contains a single tube exchanger which transfers heat into the cooling water just like a typical exchanger in the process. It does this with a patented liquid-to-liquid design which insures uniform heat transfer and realistic results.
No, nothing will at this time. Coupons are a Standard Method established by NACE and a Best Practice for Cooling Water Monitoring. SENTINEL offers an online, heated corrosion coupon to supplement the use of coupons.
The 0.5" tube specimen inside the SENTINEL is pre-weighed before use and then cleaned by the NACE standard method and re-weighed to determine metal loss over the exposure period. Pit depths and other corrosion analysis is performed on the outside surface of the tube that has been exposed to the cooling water.
Not likely. Coupons are not a heated surface and are not transferring heat through the metal like the plant exchangers or the SENTINEL exchangers. Corrosion mechanisms change significantly when heat passes through the metal.
It will!! Unless the corrosion rate is pristine, the results from the SENTINEL will always be higher than the coupon. (see question #6)
Knew Value has presented field results to a sub-committee of NACE and they found the results to be "interesting". We are preparing another paper for consideration. Metallurgists are referring to the SENTINEL tube specimens as "heated corrosion coupons". The majority of the tube specimens removed during field studies were analyzed by one of the US leading metallurgists.
The DATS technology is only monitoring scale and is not visible online. No visual inspection is possible online, only data and there is no measurement of corrosion.
There is no attempt to measure deposition online. It is evaluated just like during a turnaround. By observation. Samples are then taken and sent to the lab for analysis. Because the tube specimen is pre-weighed before exposure to the cooling water, theoretically one could weigh the tube dirty and attempt to determine the accumulation of deposit. This has proven difficult due to the deposit drying out rapidly and falling off the tube after it is removed.
Yes. Bacteria can be observed online following an excursion or if treatment is insufficient for control. When the tube specimen is removed the tube can be swabbed and analyzed.
Depending on the cooling water performance, in as little as 30 days. The first field evaluation was terminated due to poor results in 46 days.
There is no set exposure time for the SENTINEL exchanger tubes. This is up to the plant and water treatment companies. Generally, it is based on seeing significant results that may need further analysis by removing the tube specimen.
Sensors and exchanger monitoring doesn't measure corrosion. Results cannot be visually observed online during the exposure period. The clear shell of the SENTINEL exchangers allows observations and photographs while in service. Online photography is being developed for the SENTINEL which will be transmitted to our online server via cell transmission.
Knew Value data logs the flows and temperatures of the exchangers and records the information locally on an SD card as well as transmitting it to our server where is can be reviewed by Knew Value or customer personnel. We are also able to receive text or emails notifying us of a performance issue in the skid.
Two ways, online or by copying the data from the internal SD card. No cable is required to connect your computer to the device in the field.
Yes. If your Sentinel is equipped with a SIM card the data can be downloaded and viewed online.
The exchanger flow and temperature data is averaged for a given exposure period and then converted to skin temperatures and velocities using a tool downloaded from the Knew Value website.
Case studies, CTI, NACE and IWC papers can be downloaded from the Knew Value.com website. There is also a "Voice of the Customer" video and other interviews with customers on the website.
No. The SENTINEL exchanger performance for skin temperature and velocity is specific to the design of the skid exchanger. Flows and temperatures of the cooling water are significantly different when comparing a single tube exchanger on the skid to the large bundles in the plant. The objective is to operate the test exchanger at the same skin temperature and velocity.
It is not our goal to reach the same outlet temperature in the SENTINEL, and the equipment is not designed to accomplish this temperature. Too little tube surface area (one 0.5" tube) and not enough process heat (1200watts per exchanger).
Knew Value has a number of videos on the website under the "Support" tab that will assist in the start-up and operation of the skid. There is also an Operating Manual for the skid that can be downloaded. In addition, Knew Value personnel will travel to your plant site for initial commissioning and training. Consulting and travel is charged for this onsite service.
The SENTINEL has a patented liquid to liquid heat transfer process that insures uniform heating of the specimen. It is the first heated corrosion coupon that most closely simulates the conditions inside the plant exchangers. The results can be observed online. It is affordable.
As results are observed changes to the chemical program and control can be implemented and results seen immediately. No plant shutdown is required for the removal of the tube specimens and their analysis. Chemical overlays or increased dosages can be evaluated by injecting product into the SENTINEL exchangers, minimizing cost and risk of this type of program change.
The original Sentinel, Model A, required the removal of air from the simulated process loop to insure proper operation of the skid's single heater and process pump. This has been removed in the Model B and replaced with immersion heaters that are more reliable. In all the models of the SENTINEL loss of cooling water flow will most significantly affect the results of the exposure period, not unlike the corrosion coupon rack.
