Water Bath- Definition, Principle, Parts, Types, Procedure, Uses

Microbe Notes

A water bath is preferred over an open flame when heating flammable substances. It is employed to enable some chemical reactions at high temperatures.

A big container filled with warm water makes up a hot water bath. It has different design combinations, sizes, and proportions. A laboratory water bath’s container capacity ranges from 12 to 32 liters for a standard model and 50 to 100 liters for a large water bath. Most water baths feature a digital or analog interface that users may use to set the desired temperature. In contrast, some water baths include a reader that uses a current to regulate the temperature. A shaker is another feature of the water bath that is useful for homogenizing the test solution

Water Bath

Its mostly utilized in clinical and microbiology labs, university labs, environmental research, and even food technology for warming reagents, sample thawing, corrosion tests, and bacteriological investigations, among other applications. A water bath is a tool that needs additional supporting instruments to function. An incubator, a micropipette, a centrifuge, and a laboratory oven are typically used in tests involving a water bath.

Table of Contents

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Principle of Water Bath

The sensor converts the temperature of the water into a resistance value, which is then amplified and compared by an integrated amplifier. This produces the control signal, which effectively regulates the average heating power of the electric heating tube and keeps the water at a constant temperature.

Parts of Water Bath

A laboratory water bath’s container comprises an insulated metal, like stainless steel. Test samples are maintained in hot water for a lengthy time in a container.

It is mainly constructed of insulated metal or heat-resistant glass. The lid keeps the container covered, preventing water evaporation.

Temperature sensors are used as a heater in a laboratory water bath to help create heat.

It helps gauge the water bath’s temperature. It may be integrated or added on its own.

It aids in maintaining a steady temperature in a water bath.

It is found in circulating water baths which promotes water circulation inside it.

It aids in removing the water from the container.

It should be present in every water bath. The water bath is warming up while the light is on. The light will be turned off to maintain the desired temperature if the water bath achieves it.

Types of Water Bath

Shaking Water Bath

The water bath’s shaking characteristic is more precisely controlled for liquid flow. An on/off switch controls the shaking. In microbiological techniques, regular shaking allows liquid-grown cell cultures to mix continuously with the air. The features of the shaking water bath include high-precision temperature control, easy temperature adjustment, a precise and clear indication, and outstanding and dependable performance. For easier experimental observation, lighting equipment is provided in the workshop. The cabinet has a fan, and a forced-air convection unit fitted to disperse heat more evenly.

Some of the main benefits of this type of water bath include the user-friendly keypad operation, the straightforward bath drains, the programmable shaking frequencies, etc.

Circulating Water Bath

It is also known as a stirrer water bath. In the baths with circulating water, the water is properly circulating. Stirrers or circulating water baths may be useful for applications where the samples must have consistent or uniform temperatures. The circulating water bath uses continuously circulating water to efficiently and dependably obtain and maintain the desired water temperatures required for the cooling or heating of samples and reagents. It enables quick heating or cooling of samples across a wide temperature range. Enzymatic and serologic testing may be used for these purposes. It receives proper circulation, which leads to a more stable temperature.

Non-circulating Water Bath

Such laboratory water baths rely on the convection mechanism rather than heating the water uniformly. As a result, the water bath’s capacity to control temperature is less exact. We can also add accessories to stir the water bath to enhance heat transmission. Water baths are safe to use up to 99.9 °C. When the temperature is greater than 100 °C, substitutes may be used.

Polycarbonate Water Bath

Inside the bath, there is a controlled heating system. The container is made of transparent polycarbonate, and its temperature can reach 100 degrees Fahrenheit.

Analog and Digital water bath

Analog water bath

The most basic kind of water bath is an analog one. It is affordable and simple to use. However, it only has a few issues. The analog water bath’s accuracy is lower than the digital water bath’s, which is the first issue. There isn’t a display board in addition to that. The water’s true temperature won’t be visible as a result.

Working mechanism of analog water bath

When the machine is given a power supply, the main indicator will glow. Then the current will go to the thermostat. From the thermostat, the current will flow through the water immersion heater. The thermostat will permit current to pass through the heating rod if the water’s temperature is lower than the predetermined level. Consequently, the water will start to warm up. The thermostat will shut off when the water temperature reaches the predetermined level. The heating rod won’t, therefore, receive any current. The water’s temperature then starts to drop. The heating indicator will also stop glowing.

Digital water bath

An upgraded version of an analog water bath is a digital water bath. It’s extremely pricey. However, using it is simple. This version is more accurate. Similar to that, it has a display board that enables the user to view the real temperature of the bath’s water.

Working Mechanism of digital water bath

The solid-state relay (SSR) and PID controller work together to manage the water immersion heater. The controller will deliver a certain DC voltage to the relay if the water temperature is below the predetermined value. The relay will turn on, causing the AC to flow to the heating rod. As a result, the heater starts to warm the water. The PID controller will constantly activate and deactivate the relay when the actual temperature of the water approaches the desired value. Thus, the heating rod will continuously cycle ON and OFF. As a result, the water bath contributes to the maintenance of a nearly precise result with a variance of no more than 1°C. The sensor measures the water’s temperature using a resistance temperature detector (RTD). The temperature is then converted to a resistance value, which is supplied to the controller. This incoming signal will be compared to the preset value by the controller.

Controls of a Laboratory Water Bath

Temperature controller: A temperature controller, either digital or dial, is a standard feature of all water baths.

Safety controller: A safety controller is often found above the temperature controller or connected to the indicator light in most water baths. A safety controller aids in determining the highest temperature that the water bath should reach. The safety light will turn on if the water bath somehow manages to meet the temperature that the safety controller has established. Even with a higher temperature, a water bath cannot achieve a temperature greater than the safety settings.

Shaking controller: It may enable us to accelerate, decelerate, or activate the shaker.

Operating procedure of Water Bath

  1. Ensure the equipment is clean and the temperature indicator is calibrated by the due date.
  2. Plug in the power source.
  3. Make sure the water in the bath has enough depth for the heating element to be poured in.
  4. Turn “ON” the instrument’s main power source.
  5. In order to set the desired temperature, press the SET key. The temperature can be changed by pressing any or both of these buttons.
  6. Use a calibrated thermometer to confirm the temperature.
  7. The temperature sensor will retain the set temperature whenever a water bath is used.
  8. After use, turn “OFF” the main power source and the instrument’s mains.
  9. After usage, completely dry the instrument and then replace the lid.

Applications

Advantages

Limitations

Precautions

Examples of Water Bath

Laboratory water bath WTB11 (Manufacturer: Memmert GmbH + Co. KG)

Circulating water bath HBR 4 control (Manufacturer: IKA)

Shaking water bath SWB-110X series (Manufacturer: Biobase)

Circulating water bath MDBS series (Manufacturer: Medline Scientific)

Shaking water bath WB-S30 (Manufacturer: Bioevopeak)

References

  1. https://www.labkafe.com/blog/how-to-use-water-bath-in-laboratory-working-principal-types-maintenance
  2. https://www.pharmaguideline.com/2011/01/sop-for-operation-and-calibration-of_5.html
  3. https://www.munroscientific.co.uk/what-are-kinds-parts-of-water-baths
  4. https://antiteck.com/laboratory-water-bath-2/
  5. https://www.hope-academic.org.uk/HandS/Risk%20assessments/waterbaths.htm
  6. https://www.tec2med.com/water-bath-working-handling-maintenance/
  7. https://microbiologynote.com/laboratory-hot-water-bath-working-principle/
  8. https://www.directindustry.com/prod/memmert-gmbh-co-kg/product-28305-2379929.html
  9. https://www.medicalexpo.com/prod/ika/product-70924-724917.html
  10. https://www.medicalexpo.com/prod/biobase/product-84845-807555.html
  11. https://www.medicalexpo.com/prod/medline-scientific/product-76782-978624.html
  12. https://www.medicalexpo.com/prod/bioevopeak/product-301335-1056196.html

About Author

Prakriti Karki completed her B.Sc. in the field of Microbiology. She is interested in working in the interface of immunology, microbiology, synthetic biology, bioinformatics, and open science. She has worked as a project lead at Media Lab Nepal, as a research associate in the BMSIS program, and as an awareness community member at the iGEM WiSTEM initiative.

3 thoughts on “Water Bath- Definition, Principle, Parts, Types, Procedure, Uses”

budmiki talang how can i cite this paper Reply Sagar Aryal

You can cite as: Karki, P. (2022, October 13). Water Bath- Definition, principle, parts, types, procedure, uses. Retrieved from https://microbenotes.com/water-bath-definition-principle-parts-types-procedure-uses/ Reply

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