The **WRPP-JKM-R** is a specific model of a **platinum-rhodium thermocouple**, primarily used for high-temperature measurements in industrial environments (such as furnaces, kilns, and smelting). Below is a breakdown of its electronic and physical components. --- ### 1. General Specifications | Feature | Details | | :--- | :--- | | **Graduation Mark** | S-type (Platinum Rhodium 10 - Platinum) | | **Temperature Range** | 0°C to 1300°C (Continuous), up to 1600°C (Short-term) | | **Accuracy Class** | Class I or Class II (Standard) | | **Material** | Noble metal (Platinum Rhodium) | --- ### 2. Core Electronic Parts The functionality of the WRPP-JKM-R relies on the **Seebeck Effect**. The electronic structure consists of the following: #### A. Thermode (The Sensing Wires) This is the heart of the device, consisting of two dissimilar metal wires: * **Positive Pole (+):** Platinum-Rhodium 10 (90% Platinum, 10% Rhodium). * **Negative Pole (-):** Pure Platinum. * **Function:** When the "hot junction" (tip) is heated, a small DC voltage (millivolts) is generated proportional to the temperature difference between the tip and the "cold junction." #### B. The Junctions * **Measuring Junction (Hot):** Where the two wires are welded together. This is placed in the heat source. * **Reference Junction (Cold):** Where the thermocouple connects to the measuring instrument (compensating wires). #### C. Insulation * **Ceramic Beads/Tubes:** High-purity alumina ($Al_2O_3$) sleeves are used to prevent the two wires from short-circuiting against each other or the outer protection tube. --- ### 3. Structural & Protective Components Since these sensors operate at extreme temperatures, the internal electronic parts are protected by: 1. **Outer Protection Tube:** Usually made of **Corundum** (Recrystallized Alumina). It protects the platinum wires from chemical erosion and physical damage. 2. **Junction Box (Terminal Head):** Often waterproof or explosion-proof, containing the **Terminal Block** where the thermocouple wires are screwed into the external lead wires. 3. **Process Connection:** Usually a fixed thread or flange (indicated by the "JKM" suffix in some manufacturer codes) for mounting. --- ### 4. Technical Comparison (S-Type Characteristics) The WRPP-JKM-R belongs to the S-type family, which is preferred for high-precision industrial use. | Parameter | S-Type (WRPP) | | :--- | :--- | | **Stability** | Excellent (Resistance to oxidation) | | **Output Signal** | Low (approx. 10 $\mu V/^\circ C$) | | **Precision** | Highest among standard thermocouples | | **Cost** | High (due to Platinum content) | ---