The KOBOLD DSV series is a high-quality, variable area flow switch specifically designed for accurate measurement and monitoring of liquid flows. Based on the well-known float-type flow meter principle, the DSV series features a patented design that replaces the conventional tapered measuring tube with a cylindrical flow tube equipped with conical slots around its periphery. This innovative design significantly reduces sensitivity to dirt and ensures stable float guidance, leading to reliable and repeatable switching performance.

Principle of Operation

The DSV flow switch operates on a simple yet effective magnetic principle. The device consists of a vertical cylindrical measuring tube with conical slots, a float containing a permanent magnet, and a bistable reed contact housed in an external, height-adjustable switch enclosure. As the measured liquid enters from the bottom and flows upward, it lifts the float. The float rises proportionally to the flow rate. When the magnetic field of the rising float reaches the tip of the reed contact, the switch closes. As the flow rate increases further, the float continues to rise until it hits an internal stop, which prevents the float from moving beyond the reed contact's operating range, ensuring bistable switching behavior.

Key Features

• Patented Measuring Tube: The cylindrical tube with conical slots eliminates issues associated with guiding a float inside a tapered tube, offering improved stability and dirt resistance.
• Hazardous Area Compatibility: The DSV series can be used in hazardous areas; the reed contact is suitable for temperature class T4 / T125°C.
• Bistable Switching: The switching behavior is maintained even with flow variations, ensuring the output state is stable and does not flutter.
• Hermetic Separation: The fluid is hermetically separated from the electrical contact, providing high safety and reliability.

Technical Specifications

• Measuring Range: The DSV series offers various ranges for water from 0.25-1.25 L/min up to 10-130 L/min.
• Accuracy: ±4% of full scale.
• Process Connection: Available with G ¼" to G 1¼" female threads or ¼" to 1¼" NPT female threads.
• Materials: Housing is made of aluminum (not media-contacted); process connections are available in nickel-plated brass (Ms 58) or stainless steel 1.4404; the measuring tube is borosilicate glass.
• Electrical Data: Reed switch contact (SPDT), maximum switching voltage 250V, maximum switching current 1A, maximum switching power 40W.
• Environmental: Operating temperature range from 0°C to +100°C (media), pressure rating up to 10 bar, protection class IP54 or IP65.

Applications

The DSV series is widely used in industrial automation, water treatment, pumping applications, cooling systems, and various process industries for monitoring flow of water, aqueous solutions, and other low-viscosity, clean liquids. It is also suitable for welding applications.