In order to keep your scope up and running in excellent shape, some basic maintenance must be undertaken, this article focusses on the chilled water that cools your scope. The majority of TEM, SEM, and Dual Beam systems contain chillers that are used for cooling pumps or lenses. The water in the chillers must have the right temperature, chemistry, and cleanliness.
Here are some of the basics that you need to check twice a month, if you would like any more information or help on this matter please get in contact with TSS Microscopy.
The water must have the right pH. Highly acidic water can erode parts and adversely reduce the lifetime of customers’ scope. Standard pH paper can be used to check the pH level, which should range from 7.5 to 9. If the pH is lower, it means it is acidic and therefore some action has to be taken (if this is the case, customers can contact the company for more information). The following image shows the extent of damage caused to the SEM’s lens by highly acidic water. It can be disastrous.
Another important parameter is the temperature of the water that cools the customers’ scope. If a chiller is set very hot, it can lead to inadequate cooling, and as a result, drift and other bad effects will become apparent. If the chiller is too cold, it can cause condensation, which in turn can have detrimental effects. The temperature usually ranges between 17 and 21 °C (this slightly depends on the scope and the environment, so customers can contact the company for more information).
Some of the most difficult and service-intensive problems that are encountered are dirty water, clogs, and contaminated water. This can be both time- and cost-intensive for everyone involved. The water must be clean and free from algae because otherwise, the lenses can become clogged and other major parts of the scope can heat up! An opaque water tubing and 5 µm inline filter can help in reducing the chances of algae growth. In case these are not available on the system, customers can contact the company, which will then work with them to ensure that their system is best set up for long microscope life and clean water.
Specific recommendations are provided by each chiller manufacturer to preserve clean cooling water. Some of the main points are given below, but TSS can offer more details, as required.
- Distilled water is generally preferred because this water has been boiled and is free from microorganisms
- Lab-grade propylene glycol can be added to produce a 10% solution
- The fungicide, dichlorophene, can be added and sprinkled on the chiller’s top surface. A small amount should be used to cover the top surface of the water in the chiller tank.
- The blue or colorless versions of Koolance can be used
- Ethylene glycol mixtures or water are also acceptable
In summary, TSS recommends that the following items to be checked:
- Use a pH paper test to validate whether the pH of the cooling water is correct
- Validate that the chiller’s temperature is set correctly
- Check the cleanliness of the water by looking in the chiller and observing whether there are any floaters or algae. Cooling lines/tubing should also be checked. If customers observe something that concerns them, they can take a photo and contact TSS Microscopy. The company will make suggestions on what needs to be done.
- Check the chiller’s flow rate. Ensure that the water is flowing and at the correct specified values for the instrument. For more detailed information, customers can contact TSS on their specific scopes.
This information has been sourced, reviewed and adapted from materials provided by TSS Microscopy.
For more information on this source, please visit TSS Microscopy.