The kink in the mercury thermometer prevents mercury from falling into the bulb from the capillary tube. It guarantees that the user takes the right temperature reading. The thermometer with a kinked stem is called a kinked-stem thermometer.
Its function is to ensure that no matter how long the stem is out of the liquid, the thermometer will still work properly. Without the kink, if the stem was ever completely removed from the fluid it would be impossible to read the temperature due to the presence of mercury in all thermometers.
Kinked-stem thermometers are useful in places where corrosion is an issue, such as hospitals and food processing facilities. The stem does not contact the liquid itself but instead is connected to a glass bulb that holds the mercury in suspension. This separation allows the mercury thermometer to work even if the stem is removed from the liquid.
There are two types of kinked stems: internal and external. An internal kink occurs on thermometers with plastic or rubber bulbs; this type of kink cannot be seen by outsiders. External kinks are found on thermometers with glass bulbs; these kinks can be seen easily by others.
The kink regulates the in and out flow of mercury from the bulb, causing the mercury level in the tube to climb and decrease slowly. As a result, the kink near the bulb in a clinical thermometer prevents the mercury level from decreasing when removed from the mouth. This keeps the temperature reading accurate even after the thermometer is removed from the patient's body.
In children, removing the thermometer from the mouth can cause the mercury level to drop too far, leading to an inaccurate reading. To prevent this from happening, pediatric thermometers have stems that are more rigid than those used with adults. The harder stem resists bending when removed from the child's mouth, so the thermometer stays in place even if pulled away.
Clinical thermometers need to be cleaned after each use to remove bacteria that may otherwise contaminate the next patient. In general, clean thermometers are less likely to give false readings.
However, some bacteria can grow inside the stem of the thermometer, which could lead to another type of error. These "bad" bacteria produce carbon dioxide as they metabolize food substances. This gas accumulates inside the stem and can cause it to inflate. When the thermometer is re-used, this increased pressure can cause the mercury to leak out through any holes in the stem. As a result, the temperature read on these thermometers is also inaccurate.
The kink in the thermometer prevents the mercury in the capillary tube within the bulb from falling. The kink makes it easier for the user to see the right thermometer reading. Before using the thermometer, the individual shakes it to bring the mercury level back to normal. Then, the person uses the kink to place the tip of the thermometer in their mouth and holds it there for at least one minute.
In conclusion, the role of kink in a clinical thermometer Class 6 is to prevent the mercury in the bulb of the thermometer from falling when the device is not in use. This helps the user to get an accurate reading the next time they use the thermometer.
Kink is a crucial factor in clinical thermometers. The kink prevents the mercury in the capillary from returning to the bulb. As a result, it separates the hot mercury from the cold mercury and allows the user to record the reading when the thermometer is removed. Without the kink, only a single temperature would be recorded when using this type of thermometer.
The traditional method for making a thermometer with a kink is to insert the stem of the thermometer into a hole in a piece of wood, then bend the tip of the thermometer down over the edge of that hole. This bends the tip of the thermometer back toward the bulb, creating a kink.
Today's thermometers are made from plastic rather than wood. They still have a kink, but one that can't be seen without opening the device up. The stem of the thermometer goes inside the body of the device, where it is protected from damage while still allowing the user to read the temperature when the device is removed.
A traditional glass thermometer has no kink because it uses a metal rod instead. The user reads the temperature by looking through a window on the side of the thermometer.
These days, most glass thermometers have a kink to protect the reader from touching the fluid-filled bulb.
Mercury is included in this glass bulb. (3) A tiny, gleaming thread of mercury may be seen in the thermometer tube outside the glass bulb. The kink prevents mercury from flowing back into the thermometer bulb when the thermometer bulb is withdrawn from a patient's mouth.
The thread of mercury becomes visible if you wrap aluminum foil around the neck of the bulb for about 30 minutes. Then remove the foil, blow out the mercury vapor, and wipe the bulb clean. You will see the thread hanging down inside the tube.
This metal coil keeps the mercury in the tube while allowing it to become liquid again if the bulb is left at low temperatures. If the mercury freezes, however, it cannot refreeze once it has frozen, so make sure your know how to use your thermometer before you put it in practice!
Digital thermometers use a microprocessor instead of an electromechanical sensor to measure temperature. These thermometers do not need to be read in daily use because they store the last reading automatically. They can also measure temperatures more accurately than other types of thermometers. However, these thermometers do require a battery that must be replaced periodically. In addition, there are no analog readings on digital thermometers so if you mix up batteries or lose yours then you will need to read the thermometer again.
The jerk to the thermometer will allow mercury to flow into the bulb, lowering the mercury level below the typical temperature. This allows accurate measurement of the patient's temperature.
At the end of the lesson, you will be asked to explain why we need to jerk a clinical thermometer before we measure the body temperature. You may use any example that comes to mind.
Here are some examples:
• The thermometer is used to check temperatures of patients in hospitals and other medical settings. It must be kept cold until just before use so that it does not cause injury by dropping to too low of a temperature. At that point, it should be warmed by jerking the handle up and down several times.
• Thermometers used in homes and businesses to measure body temperatures of animals, such as cows, pigs, and sheep, must be treated with caution because they can transmit diseases from one animal to another. So when taking an animal's temperature, it is important to follow proper hygiene procedures.
• Temperature measurements play an important role in laboratory studies too. Laboratory instruments require calibration using standards of known temperature. These standards are usually liquid gases such as nitrogen or oxygen gas at different temperatures.