Aschematic diagram of the internal workings of a pod-type thermostat. This type is used in appliances that have a variable temperature control. It consists of an oil-filled pod connected to the switch by a capillary tube. When the oil in the pod is heated or cooled, it expands or contracts in the tube and operates a diaphragm. The diaphragm acts on the switchgear thus breaking the circuit and in this instance, ‘making’ the other. The cooling oil contracts, pulling the switch the opposite way — back to its original position; the process repeats if temperatures change. Read the rest of this entry »
The humble kettle has been given a new image in recent years. Simple versions consisting of only a container with a heating element fixed inside are still available, but for many years the trend has been towards the automatic kettle that turns off once the water has boiled.
Some more recent models have been further improved with high-speed elements and spout filling. The latest jug version combines all the features of a modern kettle with the added feature of the handle’s being positioned on the side, so that the user avoids the steam when pouring.
As with irons, cable damage through wear and tear and misuse tends to be a common fault. Cordless kettles and jugs preempt this problem. They are similar to cordless irons in that they require a power base that has its own mains lead. When the cordless kettle is placed on its base, electrical contact is made to its heating element. The operation from then on is like any other automatic kettle. Read the rest of this entry »
The toaster is another appliance that uses heating elements and, in most instances, a bi-metal strip thermostat to control the length of time the bread is exposed to them. This, in turn, relates to the degree of browning required by varying the position of the bi-metal contact points. When bread is inserted, a latched spring system is actuated to hold the bread carrier in place. At the same time, it makes a switch contact to supply power to the elements. The heat from the elements toasts the bread and also heats the bi-metal strip, causing it to bend. Read the rest of this entry »
