All About Float Level Switches – PSI Automation

All About Float Level Switches!

Simple and effective

All About Float Level Switches!

Simple and effective

What are Float Level Switches

Float Level Switches are handy little devices used to detect and control liquid levels for a variety of different applications. They are relatively simple and effective. They can be used to stop liquid in a tank or vessel from overflowing, or prevent it from emptying.

What are the different types of float level switches?

Float switches can come in an array of configurations, however they are typically catagorised into vertical and horizontal. Here we will be talking in detail about two basic examples of each.

Vertical Float Level Switches

Here we can see the switch is installed in the top of the tank, as the water level increases, the float rises and activates the switch. It can also be installed in the bottom to help detect when the tank level is too low. Below we will discuss how the switch is activated.

Horizontal Float Level Switches

Here we can see the switch is installed in the side of the tank, following the same principal as the vertical ones, as the float rises it activates the switch. These particular ones are sometimes referred to as finger level switches due to the float looking a bit like a finger moving up and down.

How does a float level switch work?

Float level switches commonly use reed switches and magnets to activate or deactivate the switch, aka open or close the circuit.

What is a reed switch?

Reed switches are fairly simple contraptions. They are usually very small glass capsules, inside containing two magnetised reeds from either side. When a magnet comes in proximity, the magnetic attraction forces the closure of the reeds. This allows a current to flow through the leads at either end of the reeds.

So how are they configured in a float level switch?

In a vertical float level switch, the reed switch is in the non-magnetic stem, while the magnet is in the float.

As you can see in the below demonstration, as the liquid level rises, the float rises with it, moving the magnet into position, causing the reed switch to close, allowing a current to flow through.

There are plenty of uses for vertical float level switches.

For example, in this instance the signal may be telling another device to stop filling up a tank, or alert an operator that the tank is full and needs emptying.

A vertical level switch can also be placed at the base of the tank, instead telling another device that it needs to start filling the tank again, or alert an operator that the tank is emptying.

Here we can see a horizontal level switch. It follows the same basic principals, just configured differently.

As you can see they are simple devices that are very effective for monitoring liquid levels.

Products

We stock a wide range of miniature float level switches, in a variety of configurations and materials.

BLS-02-PP – Vertical Float Level Switch Plastic

Level Switch consisting of a magnetic float unit stem with magnetic reed switch, the magnetic float moves with liquid level to actuate a hermetically sealed magnetic switch within the unit stem

Maximum Pressure: 8 bar
Temperature Range: -10 -to 70°C
Switch Voltage: 250VAC/200VDC
Switch Rating: 70VA
Set Point Accuracy: ±2mm in water
Thread: M8 or M10

BLS-02-SS – Vertical Float Level Switch Stainless Steel

Float level switch consists of a magnetic float unit stem with a magnetic reed switch. The magnetic float moves with liquid level to actuate a hermetically sealed magnetic switch within the unit stem.

Maximum Pressure: 20 bar
Temperature Range: -30 -to 125°C
Switch Voltage: 250VAC/200VDC
Switch Rating: 70VA
Set Point Accuracy: ±3mm in water

BLS-05-SS – Vertical Float Level Switch Side Entry – Bent Stem

Bent stem, made of stainless steel SUS304 or SUS316L, with G1/8″ threads.

Maximum Pressure: 8 bar
Temperature Range: -10 – 120°C
Mounting Thread: G1/8” Male
Switch Voltage: 250VAC/200VDC
Switch Current: 0.5A
Set Point Accuracy: ±2mm in water

BLS-06-E-PP – Horizontal Float Level Switch External Side Entry

Horizontal external mounting level switches, made of Plastic (PP), for lower cost, with 1/2” NPT mounting threads.

Maximum Pressure: 8 bar
Temperature Range: -20 – 70°C
Mounting Thread: 1/2” NPT
Switch Voltage: 250VAC, 200VDC
Switch Current: 0.5A
Power Rating: 50VA
Set Point Accuracy: ±2mm in water

BLS-06-E-SS – Horizontal Float Level Switch External Side Entry

Horizontal external mounting level switch, made of Stainless Steel, with 1/2″NPT mounting threads.

Maximum Pressure: 16 bar
Temperature Range: -10 – 120°C
Mounting Thread: 1/2” NPT
Switch Voltage: 250VAC, 200VDC
Switch Current: 0.5A
Power Rating: 50VA
Set Point Accuracy: ±2mm in water

BLS-06-I-PP – Horizontal Float Level Switch Internal Side Entry

Horizontal internal mounting level switches, made of Plastic (PP), for lower cost, with M16 mounting threads.

Maximum Pressure: 8 bar
Temperature Range: -20 – 70°C
Mounting Thread: M16
Switch Voltage: 250VAC, 200VDC
Switch Current: 0.5A
Power Rating: 50VA
Set Point Accuracy: ±2mm in water

BLS-06-I-SS – Horizontal Float Level Switch Internal Side Entry

Horizontal internal mounting, with M16 thread, made of Stainless Steel.

Maximum Pressure: 16 bar
Temperature Range: -10 – 120°C
Mounting Thread: M16 thread
Switch Voltage: 250VAC, 200VDC
Switch Current: 0.5A
Power Rating: 50VA
Set Point Accuracy: ±2mm in water