A thermowell is a device to reduce the risk of leaks while taking temperature readings. It is basically a long glass tube which is sealed on one end and partially filled with a fluid to transfer heat such as mineral oil. A thermometer is inserted into the tube and the sealed end would typically be immersed in the contents of a boiling flask or short path head which transfers heat to the thermometer and allows temperature readings to be taken. The opposite end has a female joint for an air tight and dependable seal.
Note: the length of the thermowell is fixed at 2" beyond the end of the joint grind. If you'd like us to make a custom thermowell for you, contact us with your preferred joint size and measurements.