Float type level transmitters represent one of the most reliable solutions for liquid level measurement in industrial applications. These devices offer continuous, dependable level measurement and enable remote monitoring capabilities. 

Working Principle of Float Type Level Transmitters

The transmitter’s operation is based on a simple yet effective mechanism. It consists of a float that moves along a guide tube containing a PCB strip. This PCB strip is embedded with a series of resistors and reed switches arranged in a chain formation, effectively creating a variable resistor system.

The PCB strip connects to a converter card housed within the transmitter’s enclosure. As liquid levels change, the float moves accordingly and activates reed switches inside the tube in a sequential manner. Each activated switch causes a precise change in resistance/voltage, which the converter card translates into a standard 4-20mA output signal that can be integrated with various control systems.

Understanding Accuracy in Float Type Transmitters

The accuracy of float type level transmitters depends primarily on their resolution capabilities. The transmitter operates in discrete steps determined by the spacing between consecutive reed switches. This spacing defines the resolution of the device. Techtrol transmitters are offered in two resolutions as:

1. Standard Resolution: Features 12 mm spacing between reed switches
2. High Resolution: Offers enhanced 6 mm spacing for more precise measurement

The smaller the spacing between reed switches, the higher the resolution and consequently, the greater the accuracy of level measurement. 

Maximum Measuring Range and Dead Band Concept

The float’s design is customised based on the specific gravity of the liquid being measured. For proper operation, the float must remain partially submerged, with a portion below and a portion above the liquid surface. The actual level measurement occurs at the float’s immersion point.

However, due to the physical dimensions of the float, there are areas at both the top and bottom of the guide tube where accurate level measurement is not possible. These areas are known as “dead bands”:

Measuring Range = Guide Tube Length – (Top Dead Band + Bottom Dead Band)

Understanding these dead bands is crucial for proper installation and configuration of the transmitter to ensure that critical level measurements fall within the effective measuring range (refer image below).

Advantages of Pune Techtrol Float Type Level Transmitters

Techtrol’s float type level transmitters offer several advantages that set them apart in industrial applications:

1. Customized Options: Offered in both standard (12 mm) and high-resolution (6 mm) configuration with customised lengths up to 4 metres
2. Plug & Play: Factory calibrated, ready to install
3. Reliability: Provides continuous and dependable level measurement even in challenging environments
4. Versatility: Suitable for various liquid specific gravities minimum upto 0.65 and liquid-liquid interface
5. Industry Standard Output: Delivers standard 4-20mA output and option of 4-20mA with HART or RS-485 RTU Modbus communication for seamless integration with existing systems
6. Low Maintenance: Simple mechanical design reduces maintenance requirements

Conclusion

Float type level transmitters from Techtrol provide reliable and accurate continuous level measurement for diverse industrial applications. When selecting a float type level transmitter, consider the required measurement precision to choose between standard or high-resolution models. Additionally, understanding the concept of dead bands and effective measuring range ensures optimal installation and performance tailored to specific process requirements.