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Application of J-CONTROL microwave level switches in dry quenching of coke: The level of the dust removal bin is an important monitoring point in the dry quenching system. If this level is too high, coke powder from the dust removal bin will enter the nitrogen circulation channel; the high-speed airflow carried by this powder can scour the heat exchange tubes in the boiler, leading to tube failure and severely affecting the safe operation of the system. If the material level in the dual-fork ash hopper during dust removal is too low, the high-temperature coking powder will fall directly into the lower water-cooled sleeves, causing damage to these sleeves. The damaged areas will allow air to enter the nitrogen circulation circuit that operates under negative pressure, leading to the combustion of the coking powder and severely affecting the safe operation of the system. 1. Current status of material level detection in the double-fork ash hopper for primary dust removal. The temperature of the material being measured in this type of ash hopper is around 1000°C. Due to its special operating conditions, traditional contact-type capacitive level gauges are generally used for detection; however, in long-term practical use, various common problems have arisen. ①The insulator at the ends of the electrodes in capacitive level gauges is made of ceramic; as a result, the electrodes and insulator are prone to damage during handling, loading/unloading, installation, and maintenance, which imposes high requirements on all stages of the process ； ②During installation and maintenance, taking into account the material properties and the different expansion coefficients of various materials, it is not possible to insert or remove them quickly in order to avoid deformation of the materials caused by thermal shock resulting from sudden temperature changes (current operational guidelines specify that the speed at which electrodes should be inserted or removed is 10 cm/min). As a result, online replacement is essentially not feasible, and any damage to the equipment can pose challenges to continuous production ； ③During the long-term operation of the dry quenching system, coke dust adhering to the capacitive level gauge can cause false readings; it is necessary to manually remove this dust, which requires a lot of maintenance effort and interferes with normal production ； ④Since the ash bin operates under negative pressure, and the installation holes are connected to the interior of the ash bin, if the sealing at the installation flanges is not proper, air will be drawn in, which can ignite the coke powder and subsequently damage the capacitive level gauge. Level gauges designed for such extreme conditions are very expensive, and ordinary manufacturers cannot afford the cost of replacing them frequently ； 2. Detection principle and system composition of microwave level switches. A microwave level switch consists of a signal transmitter and a signal receiver, which are installed on either side of the silo at the same height and in corresponding positions. The signal emitted by the transmitter can pass through the silo via high-temperature mounting accessories and be received by the receiver. After receiving the signal, the receiver determines whether there is material in the bin based on the strength of the signal. The operation diagram of the receiver panel is shown below. By holding down the [DETECT LEVEL] button while rotating the [DETECT ADJ] button, it is possible to set the intensity of the receiver’s response. The intensity is indicated by the number of segments on the [RECEPTION LEVEL] display; there are 10 segments in total, and the higher the number of segments, the greater the intensity of the response. Once the desired intensity has been set, release the [DETECT LEVEL] button. The knobs [GAIN] and [SCALE] are used to adjust the gain and microwave sensitivity, respectively. When the number of grid points of the wave received by the receiver is less than the set threshold value, the receiver determines that the material is empty and outputs a signal ； When the number of grid points of the wave received by the receiver exceeds the set threshold value, the receiver determines that the container is full and outputs a signal. Additionally, 【ON/OFF DELAY】 is the key for setting the delay time, with a range of 0 to 10 seconds. Under normal operating conditions, turning the 【ON/OFF DELAY】 knob clockwise by five notches is sufficient to fully prevent false alarms during the material cutting process. 3. Installation: To obtain accurate measurement data and ensure that the signal emitted by the microwave transmitter can be clearly detected by the receiver, it is optimal to install the transmitter of the microwave level switch at the same location where the original capacitive level gauge was installed. This maintains the same detection position for the coke powder, with no impact on the production process. The microwave receiver should be installed directly opposite the microwave transmitter, at the same height as the latter’s location. To meet requirements such as level monitoring inside the double-branch hopper, an additional 80 mm hole is drilled at a position 90 degrees away at the same horizontal level as the microwave level switch; a welding fitting, flange, and blind plate are then used to form an observation hole. The location of the opening is indicated in the figure below. To ensure optimal performance of microwave level gauges and to prevent substances such as metal anchors that could be present in the filler material for double-fork hoppers and interfere with the detection by electromagnetic level switches, pre-fabricated steel pipe components are typically used, after which holes are drilled in the double-fork hopper to install high-temperature mounting accessories. 4. Performance: Microwave level switches excel in practical engineering applications due to their ease of replacement, high safety levels, lack of need for nitrogen purging, long service life, and minimal maintenance requirements. They have received high praise from users, providing a reliable guarantee for the safe and stable operation of dry quenching systems.