BATH & CHILLER RESOURCE GUIDE Questions to Ask When Buying a Bath or Chiller Water Bath Basics Features to Consider When Buying a Laboratory Water Bath Choosing the Right Fluid for Your Chiller Baths and Chillers: All Roads Lead to Efficiency Bath and Chiller Design Derives from Both Capacity and Utility Bath & Chiller Resource Guide ? What if I am dealing with non-routine samples Questions to Ask or analyses? For laboratories that have a wide variety of processes or When Buying a regularly run into non-routine samples or analyses, using a more robust system may help speed up preparation and downstream Bath or Chiller analysis. Many vendors offer advanced systems capable of highly precise temperature control, plus the ability to perform reciprocal or orbital agitation. Some systems also come with What type of bath or chiller is best suited to my the ability to pre-program temperature controlled shaking application? protocols, which can save money by freeing up technician time. There are many options for water- or bead-based baths, and it is important to select the one best suited to your application based on factors such as contamination, the ability to incubate samples Top 5 Questions You Should Ask on an angle, temperature ranges, and more. When Buying a Bath or Chiller 1. Does the product have any exclusive Similarly, there are many different types of chillers to choose from including air- and water-cooled designs, and selecting an features? What sets it apart from other appropriate chiller size is essential to ensure optimal cooling vendors’ chillers or baths? and efficiency. It is important to consider the heat load and heat 2. What is the warranty period? What does dissipation required for the intended application, among many it cover? other factors. 3. Are service plans available? If so, is there an on-site option? How can a bath or chiller accommodate 4. Does the unit have the appropriate cooling temperature-sensitive samples or processes? or heating capacity for the application? A wide variety of baths and chillers are available that can Is there enough reserve capacity to accommodate temperature sensitive samples. Most baths account for environmental cooling or are outfitted with heating and cooling capabilities, usually heating losses? controlled by either analog or digital means. For more precise 5. Does the manufacturer offer the necessary control on temperature sensitive samples, a circulating bath accessories for the application? (tubing, may be best. These baths can control temperature within fluid, adapters, electronic interfaces, etc.) ±0.1°C of the desired temperature. Lab Manager 2 Bath & Chiller Resource Guide The best choice is distilled or deionized water, which will Water Bath extend the life of a water bath and keep the surface intact. However, a commercial algicide or biocide should also be added Basics to completely avoid the lagoon syndrome. The need to clean Using the right kind of water makes a difference Even after taking these measures, a water bath must still be cleaned regularly. For full cleaning protocols, consult the manual By Mike May or manufacturer. Depending on the water bath, different Even though they are frequently used, water baths might be guidelines may be advised. the most neglected pieces of equipment in a lab. Their use involves heating water to about 98.6°F, placing containers in the Without specific instructions, a few general rules help. First, bath, taking them out, adding more containers, and on and on, no bleach! Like the wrong water, bleach can corrode stainless creating the perfect environment for growing algae, bacteria, steel. Next, no abrasives! Instead, stick with soapy water and a and fungus. Luckily a few easy steps can prevent your water soft cloth. If desired, a commercial product made specifically bath from becoming a lagoon. for cleaning water baths can be used. Scientists use water baths for a wide variety of applications. At Some labs clean their baths with hot water. For that, about 140°F St. Olaf College (Northfield, MN), assistant professor of biology water for 30 minutes or so should kill any living contaminants John L. Giannini uses a water bath to change the temperature in a water bath. Even after that, it’s still a good idea to empty the of enzyme reactions. “The most important thing is to keep your bath and manually clean out any lagoon leftovers. water clean by changing it often,” Giannini says. The question is: What’s the best way to do that? Take a bead break Pick the right water If keeping the water clean is just too much work, replacing the water with beads may be a good solution. For applications It turns out that using the right kind of water makes a difference where a bath doesn’t circulate or shake, the water can be in a water bath. Tap water contains dissolved ions and can swapped for beads. cause issues from scaly buildup to chlorine-driven corrosion. Therefore, it is not the ideal choice for water baths. Then, it all works the same, but the bath stays cleaner. However, even with beads, some cleaning is still required. Now and then Some scientists use water from a lab purification unit. However, – depending on how a bead bath is used – the beads must be even this water can corrode stainless steel. This is because some removed and cleaned using ethyl alcohol. lab purification units include a salt back flush that can leave corrosive sodium ions in the water. Water containing these ions The best approach to heating things in a lab depends on the lab can even put pits in a water bath’s surface. and, often, the existing equipment. No matter which method is selected—water or beads—the cleaning doesn’t go away. Lab Manager 3 GasBath Generator & Chiller ResourceResource GuideGuide and transparent covers allow the user to observe the procedure Features to without continually opening the bath. However, users have additional options when it comes to the material of construction. While stainless steel is the most common material, ceramic Consider interiors may be easier to keep clean. When Buying Regularly draining and replacing the fluid in the water bath is another key way to avoid contamination, and buyers should a Laboratory consider how easy that process is going to be. Whether the water bath has a drain built in, and whether the drain is a simple valve that can be easily opened or requires a screwdriver to open, can Water Bath make a big difference for the user. Two new water bath features From construction material to accessories, that have received positive feedback are an integrated drain hose numerous options are available that makes the bath cleaner and easier to empty, and removable hinge covers that allow one to retrieve samples without having to place the cover (likely to be dripping with condensation) on the By Erica Tennenhouse lab bench. Although typically used for heating and thawing in cell culture, Additional features that make a water bath simpler to use include water baths have a variety of applications in research labs, from digital controls, integrated timers, and the ability to operate in material characterization to histological studies. Whatever the both Fahrenheit and Celsius. Because baths are typically shared application, those thinking of purchasing a new water bath for within the lab, having presets can make it more convenient to their lab should consider the range of available features that can switch settings between users. A calibration feature can save facilitate safety, help avoid contamination, and make the unit the user time and money by removing reliance on a third-party flexible and easy to use. company to perform calibration. Water bath safety is all about having over-temperature limiters and A water bath must be flexible enough to accommodate the range audible alarms that warn the users of extreme temperatures. One of samples and devices that will be placed inside it, from test situation that is best avoided is having the heater remain on after tubes to test tube racks to flasks of all different sizes. For example, all the water in the bath has evaporated. It is therefore important if users want to incubate an Erlenmeyer flask that is taller than to have a safety mechanism in place that can automatically turn the depth of the bath, they require a lid that can be configured the system off when dry running is detected. Buyers concerned to allow the neck of the flask to stick out but still cover the rest with safety should seek out UL-listed water baths, and that CE and of the bath to minimize evaporation. Ring covers are available to CSA certifications can be helpful to have as well. enable such a setup. When using a water bath, contamination prevention is essential. Finally, a feature that should not be overlooked is the availability Toward that end, having a stainless-steel reservoir is a good start of technical support. Lab Manager 4 Bath & Chiller Resource Guide down to only approximately -20°C. These simple mixtures can Choosing the be adjusted for lower temperatures by increasing the ratio of antifreeze to water. In addition to being readily available and Right Fluid for inexpensive, a water-antifreeze mixture is not flammable. Your Chiller Two extremes Most chillers are compatible with both water-antifreeze Many labs use chillers to control the cooling combinations, or more sophisticated fluids such as silicone oils. In for various processes applications that require more cooling— in the -20°C to -80°C range, silicone oils are recommended. However, viscosity is an important consideration, and lower viscosities ensure that the oil By Mike May is effectively pumped through the chiller at low temperatures.