Float Switch Basics
The liquid level float switch is a liquid level control part with a simple structure and convenient use. It is equipped with a complex circuit and will not be disturbed. As long as the material is selected correctly, any liquid, pressure and temperature can be used. The float switch uses magnetic operation, no mechanical connection, simple and reliable operation. It has been widely used in the shipbuilding industry, generator equipment, petrochemical industry, food industry, water treatment equipment, dyeing and finishing industry, hydraulic machinery, etc. When the float switch is floated by the measured medium, the float drives the main body to move, and the magnet at the other end of the float will control the magnet on the switch action lever. The float switch does not contain components such as bellows, springs, seals, etc. that cause failures. Instead, a straight float is used to drive the internal magnet of the switch, and the simple lever of the float switch makes the switch act instantly. The float cantilever angle limit design prevents the float from being vertical.
Float switch working principle
The float switch does not contain components such as bellows, springs, seals, etc. that cause failures. Instead, a straight float is used to drive the internal magnet of the switch, and the simple lever of the float switch makes the switch act instantly. The float cantilever angle limit design prevents the float from being vertical.
In a closed metal or plastic tube, design one or more magnetic reed switches, and then pass the tube through one or more hollow floating rings with ring magnets inside, and use the fixed ring to control the floating ball and the magnetic reed. The switch is in the relevant position to make the float float up and down within a certain range. The magnet in the float ball is used to attract the contacts of the reed switch, and the action of opening and closing is generated to control or indicate the liquid level.
What are the types of float switches?
Stainless steel float switch
The universal stainless steel float level switch is available in two configurations, vertical and horizontal, with 1-way 30VA or 100VA reed switch output, which can reliably detect the level of relatively clean water, diluted chemicals and light oil. Suitable media include deionized hot water and cooking oil. Stainless steel level sensor can be installed vertically in the tank or horizontally on the tank wall for high or low level alarms.
Connecting rod float level switch
The connecting rod float level switch kit provides reliable multi-point level detection of relatively clean water, diluted chemical solvents, and light oils with a maximum range of 8' (2.44 m). 1-5 channels of reed switch output are adopted, and there are integrated wiring terminals in the integrated junction box. The float level switch is made of stainless steel and is suitable for liquid level measurement in high temperature or high pressure process storage tanks.
Magnetic float level switch
Float switches are often used in the control of liquid level in storage tanks. No external power supply, side or top mounting, wide temperature and pressure range, a variety of process connections, stainless steel wetted parts and explosion-proof design for a wide range of applications.
Side mounted float switch
Magnetic side-mounted float switches are often used in tank level control. The side mounted float switch has no external power supply, side or top mounting, wide temperature and pressure range, a variety of process connections, stainless steel wetted parts and explosion proof design make it a universally applicable float level switch.
Cable float level switch
The float level switch has two chambers, which are completely sealed using a special process when processing the cable float switch. Different switching points can be adjusted via the counterweight at the end of the cable. Non-toxic and mercury-free properties allow cable float level switches to be used in drinking water.
Multi-point stainless steel float switch
Float switches are used in FM and CSA certified explosion proof and general environment applications. The float switch provides up to 4 switch points, which can be used for PLC or SCADA remote equipment inspection. Multipoint stainless steel float switches are typically used in high temperature and/or high pressure process tanks where explosion proof certification is required.
What are the float switches used for?
The float liquid level sensor is specially used for liquid level detection of various medium and small atmospheric and pressurized liquid storage tanks, remote transmission of on-site indication signals, and liquid level alarms. It can be applied to various sanitary, toxic, corrosive media and explosive Gas Hazardous Locations. There are a variety of installation forms, suitable for various forms of containers.
The float level switch is suitable for controlling the operation of the pump to maintain the liquid level, controlling the automatic loading and unloading of the tank, controlling the liquid level or supply signal, such as oil tank, automatic cleaning system, hydraulic tank, low pressure boiler, sewage treatment system.
Relationship between the liquid medium and the floating ball
- When the specific gravity of the liquid is different, the action position of the floating ball will change. Generally, when the SG is smaller than the water, the part of the floating ball immersed in the liquid will be relatively increased.
- The reference specific gravity of the float switch product is water (SG=1), so the specific gravity SG of the liquid level must be considered when selecting the float ball, which must be larger than that indicated by the float specification, otherwise, the float switch cannot float.
- For liquids with high viscosity that will not dry up, float balls with larger outer diameters should generally be used.
- The float switch uses a magnet to sense the reed switch, so the liquid level to be measured should be free of iron filings, otherwise it will affect the action of the float on the switch.