LR Rod-Connected Float Level Switch

Instrumentation and Meters

Home » LR Rod-Connected Float Level Switch

LR Rod-Type Float Level Switch

The working principle of the rod-type float level switch is direct and simple. Usually, one or more magnetic reed switches are installed at required positions inside a sealed non-magnetic metal or engineering plastic tube. A float with a built-in magnetic system is then fixed at the position corresponding to the magnetic reed switch inside the body tube, allowing the float to move up and down within a certain range. The magnetic system inside the float triggers the magnetic reed switch to close or open through the body tube, thereby generating a switching action to achieve liquid level control. This simple and proven working principle is suitable for liquid level measurement under various industrial conditions. Normally open (NO) and normally closed (NC) refer to the states when no liquid is injected. Rod-type float level switches are widely used for liquid level control and alarm in various industries such as electronics and electric power, chemical engineering, water treatment, and water supply and drainage. Rod-type float level switches are customized products. For the convenience of users, the float specifications, material properties, junction box specifications, connection specifications, and related component specifications are compiled into a table for correct model selection. The appropriate float specification should be selected according to the operating temperature, pressure, specific gravity, acid and alkali resistance, and other characteristics of the measured liquid. When purchasing, it is also necessary to determine the connection specification, the position of each action point, the action type (normally open or normally closed), and the total length.

Product Series

Product Features

The vacuum structure is suitable for various liquid level detection operations. The switch has no direct contact with the liquid, so there is no wear or tearing. The passive contact requires no power supply. Universal signal processing for voltage-free contacts, such as PLC detection, is independent of foam, conductivity, dielectric constant, pressure, vacuum, temperature, steam, condensate, bubbles, boiling effects, vibration, etc. Multiple switch points (1 to 8) can be set in a single unit to achieve multi-point control. The position of each control point can be customized according to customer requirements. All switch wires are centralized in the junction box. The ingress protection rating is IP65 or above. Construction is simple and convenient, reducing wiring costs. Installation and use are easy. The switch is calibrated once before use and requires no maintenance, ensuring reliable overall performance. Materials such as SUS304, SUS316L, PP, PVDF, and PTFE are available for selection.

Selection Table

Junction Box Selection Table

Magnetic Float Selection Table

Note

When ordering, users should also note the minimum distance between two floats and the minimum distance at the lowest point. If the spacing is insufficient, production cannot be carried out. When ordering, users can refer to the data in the table below to determine these relative dimensions. A = Minimum distance from the bottom face of the process connection B = Minimum distance between two adjacent floats C = Minimum distance from the end of the body tube D = Minimum distance between two liquid levels for one float

During model selection, users should also pay attention to the special relationship between the float and the liquid.

Select the corresponding float specification from the float selection table according to the operating temperature, pressure, specific gravity, acidity/alkalinity, and other characteristics of the measured liquid. Temperature: Maximum temperature for PVC is 80°C; maximum temperature for PP is 80°C; maximum temperature for PVDF is 150°C; maximum temperature for SUS304/316L floats is 200°C. Pressure: Maximum pressure resistance for plastic floats is 5 kg/cm²; maximum pressure resistance for SUS304/316L floatsis 40 kg/cm². Viscosity: For relatively viscous liquids, in principle, select a float with a large outer diameter and low specific gravity to overcome the surface tension of the liquid. Acidity/Alkalinity: Polypropylene is suitable for strong acid and alkali applications. For strong acid and alkali applications with temperatures above 80°C, PVDF should be selected. Alcohol, oils, etc.: Stainless steel SUS is recommended. For the food industry, food-grade SUS316L should be used. Specific Gravity: The specific gravity (S.G.) of the float must be less than the specific gravity of the measured liquid; otherwise, the float cannot float.

Note: Special customization is acceptable for this product.