The float switches refer to the simple, widely used and most reliable type of switches. It is not some that have happened just by accident, float switches until recent days are still used widely in level monitoring. But, what is the mode of functioning of the float switch?
Float switches, designed in a simple way, for a long time they more than a century have been in use to adjust the flows of water in mills and fields. Though for centuries, a long time, they are still used currently with improved technology.
A float body with a hole in it rises and falls in respect to the amount of the liquid present. This is so because the float body has low density and buoyancy. If such movement is used through the use of the mechanical lever, such as those used in irrigation systems, then that type is called a mechanical float switch.
Recent float switches, actually, are designed to be used in an electric circuit and they are a little bit complex in design. The simplest design of the modern float switches consists of the float body with a hole embedded with a magnet in it, a guide tube to control the float body, controlling collars to adjust the movement of the float in the tube and a reed contact.
Mode of application of float switch.
If the magnetic field is applied, the electrical contacts of a float switch contain contact leaves enclosed in the airtight insulated glass body. These move at the same time towards or away each other once the magnetic field is released.
In the case of a float switch with a reed contact with a normally open function, on applying a magnetic field, the leaves are brought into contact. When the contact between the leaves is made, a current can flow via the closed leaves and a switching signal will be detected. If the float switch is operating in a normal fashion in such a way that it has a normal closing switching operation, then once you apply a magnetic field you will interfere with the contact or circuit. To have a normal closing and opening contact working at the same time at every operating time, you should choose a change-over contact which has three contact leaves.
To achieve a mono-stability which refers to the desired switching signal, you must apply a magnetic field to allow closing and opening the contact leaves keeping in mind that they are in a preload mechanically. The controlling collars fixed during manufacturing are used to position the float body at the proper location, this is very important to make sure that the generated switching signal reaches a required level.
How can you identify the float switch for your system?
You should look at the following features;
- First look at the number of switch contacts.
- The location and use of each switch contacts.
- The length covered by the guide tube.
- Types of electrical connection.
- The functioning mode
- The material used for manufacturing the switch float.