“\"Insertion depth\" – an issue worth noting and discussing
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This post was last edited by Yongshi on 2023-8-28 at 19:11. During the production process, it is often necessary to extend the measuring elements into the interior of the container pipes in order to ensure full contact with the medium, thereby obtaining accurate and representative data on parameters such as temperature, pressure, liquid level, density, pH value, and oxygen content. However, in actual design and installation processes, mistakes in reviewing drawings or during construction can lead to the neglect of this step, resulting in rework or modifications during operation. The following is a brief summary for reference and discussion: (1) Purpose of extending the measuring elements: 1. To measure the pressure and liquid level of media that tend to crystallize, solidify, or become viscous, thereby preventing measurement delays and errors caused by clogged nozzles； 2. Ensure that the top of the temperature measuring element reaches the actual temperature zone; otherwise, the measurement will be biased toward the ambient temperature (either higher or lower) ； 3. Ensure that the medium in contact with the sensor is flowing and representative. (II) Instruments involved: 1. Single and double flange melt pressure transmitters; 2. Thermometer casings; 3. Analytical instrument sensors, samplers. (III) Effects of insufficient insertion depth: 1. Pressure: Nozzle blockage, measurement lag, distortion ； 2. Temperature: The measured value tends to be close to the ambient temperature (either higher or lower) ； 3. Analysis: Poor fluidity of the sample can result in unchanged measurement values. (IV) Insertion depth: 1. Pressure: Ensure that the top of the diaphragm is at least 30 mm inside the inner wall of the container’s pipeline ； 2. Temperature: Insertion depth = 1/3 to 2/3 of DN + H = (50~100) + 120 = 170~220 ； When the diameter of the furnace chamber is large, it should not be too large either; otherwise, wear and breakage are likely to occur. 3. Analysis: It should be inserted at least 100 mm into the pipeline to ensure that the flow of the medium (such as pH meters, zirconia flow guides, etc.) is representative. (5) Process control measures: 1. Drawing review: Ensure that the insertion depth of the above three types of instruments meets the requirements ； 2. Ordering: Clarify the exact meaning of the insertion depth ； 3. Installation: For small-diameter pipelines, insert the top end at the centerline of the pipeline ； Make sure the nozzle size is consistent with the design: generally, a flange is sufficient as long as it is located outside the insulation layer, at 120~150 ； 4. Commissioning: Pay attention to the deviation between measured values and actual values. Monday, August 28, 2023
The issue of insertion depth is indeed a matter that deserves attention and discussion. During the production process, it is very important to increase the insertion depth of the measuring element, as it directly affects the accuracy of the measurement results. If the insertion depth is insufficient, it may lead to measurement lag, distortion, or a large deviation from the ambient temperature. If it is inserted too deep, it may also cause problems such as breakage or wear. For different measuring elements, the required insertion depth varies as well. For example, for pressure measuring elements, it is recommended that the top of the diaphragm extend at least 30 mm into the inner wall of the container pipeline ； For temperature sensing elements, it is recommended to insert them to a depth of 1/3 to 2/3 of the pipe’s inner diameter plus H (the length), which ensures the accuracy of temperature measurement ； For analytical instrument sensors, such as pH meters and zirconia electrodes, they should be inserted at least 100 mm into the pipeline to ensure proper flow of the medium and representative data. To avoid problems of insufficient or excessive insertion depth, we can take the following measures. First of all, special attention should be paid to this during the design review phase to ensure that the design meets the requirements. Secondly, specify the exact meaning of the insertion depth at the time of ordering to avoid misunderstandings. Then, during installation, for small-diameter pipelines, the tip of the measuring element should be inserted at the centerline of the pipe, and it is necessary to ensure that the nozzle size matches the design specifications. Finally, during the commissioning phase, it is necessary to monitor the deviation between the measured values and the actual values, and make timely adjustments and corrections. In summary, the issue of insertion depth is very important in the production process; it requires our full attention. Strict adherence to the specified requirements must be observed throughout the design, ordering, installation, and usage stages to ensure the accuracy and reliability of the measurement results. .
Whether in production or in daily life, penetration depth is an issue that deserves attention and discussion
Different thicknesses and lengths result in different effects
It’s unheard of and has never been seen before: the tops of single or double flanged diaphragms should extend at least 30 mm into the inner wall of the container pipe
In addition to preventing the medium from crystallizing inside the nozzles, plug flanges are sometimes used to prevent crystallization and scaling on the inner walls of the container; in such cases, they need to extend about 30 mm into the interior of the container, and flushing water must also be used, as is the case with ammonium sulfate crystallizers. For reference only
The melt pressure transmitter requires a mounting base specifically provided by the manufacturer； Meanwhile, TIG welding is used during the base welding process to prevent welding deformation ； Also, do not pre-install the sensor and weld it together with the base to avoid damage to the sensor due to high temperatures.
Thank you! I learned it; I hadn’t used it before!