The **KFS-04-R** is a specific model of a **water flow sensor** (often categorized under flow switches or flow meters) commonly used in water heaters, cooling systems, and industrial fluid control. Below is a detailed breakdown of its electronic components and specifications. --- ### 1. Core Operating Principle The KFS-04-R typically operates as a **Magnetic Reed Switch** flow sensor. * **Mechanical Action:** When water flows through the device, the pressure moves an internal piston or turbine equipped with a permanent magnet. * **Electronic Trigger:** As the magnet nears the external Reed Switch (the KFS-04-R unit), the magnetic field closes the circuit, sending an electrical signal to the controller. ### 2. Technical Specifications | Parameter | Typical Value | | :--- | :--- | | **Switch Type** | Normally Open (NO) | | **Max Contact Rating** | 10W / 70W (Model dependent) | | **Max Switching Voltage** | 100V DC / 220V AC | | **Max Switching Current** | 0.5 A | | **Pressure Rating** | $\leq$ 1.5 MPa | | **Operating Temperature** | -20°C to +80°C | | **Material** | PPS (Polyphenylene Sulfide) or Brass | ### 3. Key Electronic Parts The device is relatively simple but relies on high-quality passive components: * **Reed Switch Capsule:** A glass-encapsulated switch containing two ferrous reeds. This is the "brain" of the sensor. * **Internal Magnet:** Usually a Neodymium or Ferrite magnet seated on a spring-loaded plunger. * **Connecting Wires:** Typically UL1007 24AWG wires, often terminated with a JST or XH connector for PCB integration. * **Encapsulation Epoxy:** The electronic switch element is potted with epoxy resin to ensure it is 100% waterproof (IP67/IP68 rating). ### 4. Wiring Diagram Concept The KFS-04-R is a **two-wire** device. It does not require power to operate (passive switch). ```c [ Signal Source ] ---- (Wire 1) ---- [ KFS-04-R Switch ] ---- (Wire 2) ---- [ Ground/MCU Input ] ``` ### 5. Common Applications 1. **Gas/Electric Water Heaters:** To detect when a tap is turned on so the heating element can activate. 2. **Water Purifiers:** To measure flow or trigger UV sterilization. 3. **Laser Cooling Systems:** To ensure water is circulating before the laser fires (safety interlock). ---